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2024-09-09 08:52:07 +00:00
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98
kernel/drivers/misc/eeprom/Kconfig Normal file
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menu "EEPROM support"
config EEPROM_AT24
tristate "I2C EEPROMs from most vendors"
depends on I2C && SYSFS
help
Enable this driver to get read/write support to most I2C EEPROMs,
after you configure the driver to know about each EEPROM on
your target board. Use these generic chip names, instead of
vendor-specific ones like at24c64 or 24lc02:
24c00, 24c01, 24c02, spd (readonly 24c02), 24c04, 24c08,
24c16, 24c32, 24c64, 24c128, 24c256, 24c512, 24c1024
Unless you like data loss puzzles, always be sure that any chip
you configure as a 24c32 (32 kbit) or larger is NOT really a
24c16 (16 kbit) or smaller, and vice versa. Marking the chip
as read-only won't help recover from this. Also, if your chip
has any software write-protect mechanism you may want to review the
code to make sure this driver won't turn it on by accident.
If you use this with an SMBus adapter instead of an I2C adapter,
full functionality is not available. Only smaller devices are
supported (24c16 and below, max 4 kByte).
This driver can also be built as a module. If so, the module
will be called at24.
config EEPROM_AT25
tristate "SPI EEPROMs from most vendors"
depends on SPI && SYSFS
help
Enable this driver to get read/write support to most SPI EEPROMs,
after you configure the board init code to know about each eeprom
on your target board.
This driver can also be built as a module. If so, the module
will be called at25.
config EEPROM_LEGACY
tristate "Old I2C EEPROM reader"
depends on I2C && SYSFS
help
If you say yes here you get read-only access to the EEPROM data
available on modern memory DIMMs and Sony Vaio laptops via I2C. Such
EEPROMs could theoretically be available on other devices as well.
This driver can also be built as a module. If so, the module
will be called eeprom.
config EEPROM_MAX6875
tristate "Maxim MAX6874/5 power supply supervisor"
depends on I2C && EXPERIMENTAL
help
If you say yes here you get read-only support for the user EEPROM of
the Maxim MAX6874/5 EEPROM-programmable, quad power-supply
sequencer/supervisor.
All other features of this chip should be accessed via i2c-dev.
This driver can also be built as a module. If so, the module
will be called max6875.
config EEPROM_93CX6
tristate "EEPROM 93CX6 support"
help
This is a driver for the EEPROM chipsets 93c46 and 93c66.
The driver supports both read as well as write commands.
If unsure, say N.
config EEPROM_93XX46
tristate "Microwire EEPROM 93XX46 support"
depends on SPI && SYSFS
help
Driver for the microwire EEPROM chipsets 93xx46x. The driver
supports both read and write commands and also the command to
erase the whole EEPROM.
This driver can also be built as a module. If so, the module
will be called eeprom_93xx46.
If unsure, say N.
config EEPROM_DIGSY_MTC_CFG
bool "DigsyMTC display configuration EEPROMs device"
depends on GPIO_MPC5200 && SPI_GPIO
help
This option enables access to display configuration EEPROMs
on digsy_mtc board. You have to additionally select Microwire
EEPROM 93XX46 driver. sysfs entries will be created for that
EEPROM allowing to read/write the configuration data or to
erase the whole EEPROM.
If unsure, say N.
endmenu

7
kernel/drivers/misc/eeprom/Makefile Normal file
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obj-$(CONFIG_EEPROM_AT24) += at24.o
obj-$(CONFIG_EEPROM_AT25) += at25.o
obj-$(CONFIG_EEPROM_LEGACY) += eeprom.o
obj-$(CONFIG_EEPROM_MAX6875) += max6875.o
obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o
obj-$(CONFIG_EEPROM_93XX46) += eeprom_93xx46.o
obj-$(CONFIG_EEPROM_DIGSY_MTC_CFG) += digsy_mtc_eeprom.o

707
kernel/drivers/misc/eeprom/at24.c Normal file
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/*
* at24.c - handle most I2C EEPROMs
*
* Copyright (C) 2005-2007 David Brownell
* Copyright (C) 2008 Wolfram Sang, Pengutronix
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/mod_devicetable.h>
#include <linux/log2.h>
#include <linux/bitops.h>
#include <linux/jiffies.h>
#include <linux/of.h>
#include <linux/i2c.h>
#include <linux/i2c/at24.h>
/*
* I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
* Differences between different vendor product lines (like Atmel AT24C or
* MicroChip 24LC, etc) won't much matter for typical read/write access.
* There are also I2C RAM chips, likewise interchangeable. One example
* would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes).
*
* However, misconfiguration can lose data. "Set 16-bit memory address"
* to a part with 8-bit addressing will overwrite data. Writing with too
* big a page size also loses data. And it's not safe to assume that the
* conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC
* uses 0x51, for just one example.
*
* Accordingly, explicit board-specific configuration data should be used
* in almost all cases. (One partial exception is an SMBus used to access
* "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.)
*
* So this driver uses "new style" I2C driver binding, expecting to be
* told what devices exist. That may be in arch/X/mach-Y/board-Z.c or
* similar kernel-resident tables; or, configuration data coming from
* a bootloader.
*
* Other than binding model, current differences from "eeprom" driver are
* that this one handles write access and isn't restricted to 24c02 devices.
* It also handles larger devices (32 kbit and up) with two-byte addresses,
* which won't work on pure SMBus systems.
*/
struct at24_data {
struct at24_platform_data chip;
struct memory_accessor macc;
int use_smbus;
/*
* Lock protects against activities from other Linux tasks,
* but not from changes by other I2C masters.
*/
struct mutex lock;
struct bin_attribute bin;
u8 *writebuf;
unsigned write_max;
unsigned num_addresses;
/*
* Some chips tie up multiple I2C addresses; dummy devices reserve
* them for us, and we'll use them with SMBus calls.
*/
struct i2c_client *client[];
};
/*
* This parameter is to help this driver avoid blocking other drivers out
* of I2C for potentially troublesome amounts of time. With a 100 kHz I2C
* clock, one 256 byte read takes about 1/43 second which is excessive;
* but the 1/170 second it takes at 400 kHz may be quite reasonable; and
* at 1 MHz (Fm+) a 1/430 second delay could easily be invisible.
*
* This value is forced to be a power of two so that writes align on pages.
*/
static unsigned io_limit = 128;
module_param(io_limit, uint, 0);
MODULE_PARM_DESC(io_limit, "Maximum bytes per I/O (default 128)");
/*
* Specs often allow 5 msec for a page write, sometimes 20 msec;
* it's important to recover from write timeouts.
*/
static unsigned write_timeout = 25;
module_param(write_timeout, uint, 0);
MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
#define AT24_SIZE_BYTELEN 5
#define AT24_SIZE_FLAGS 8
#define AT24_BITMASK(x) (BIT(x) - 1)
/* create non-zero magic value for given eeprom parameters */
#define AT24_DEVICE_MAGIC(_len, _flags) \
((1 << AT24_SIZE_FLAGS | (_flags)) \
<< AT24_SIZE_BYTELEN | ilog2(_len))
static const struct i2c_device_id at24_ids[] = {
/* needs 8 addresses as A0-A2 are ignored */
{ "24c00", AT24_DEVICE_MAGIC(128 / 8, AT24_FLAG_TAKE8ADDR) },
/* old variants can't be handled with this generic entry! */
{ "24c01", AT24_DEVICE_MAGIC(1024 / 8, 0) },
{ "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) },
/* spd is a 24c02 in memory DIMMs */
{ "spd", AT24_DEVICE_MAGIC(2048 / 8,
AT24_FLAG_READONLY | AT24_FLAG_IRUGO) },
{ "24c04", AT24_DEVICE_MAGIC(4096 / 8, 0) },
/* 24rf08 quirk is handled at i2c-core */
{ "24c08", AT24_DEVICE_MAGIC(8192 / 8, 0) },
{ "24c16", AT24_DEVICE_MAGIC(16384 / 8, 0) },
{ "24c32", AT24_DEVICE_MAGIC(32768 / 8, AT24_FLAG_ADDR16) },
{ "24c64", AT24_DEVICE_MAGIC(65536 / 8, AT24_FLAG_ADDR16) },
{ "24c128", AT24_DEVICE_MAGIC(131072 / 8, AT24_FLAG_ADDR16) },
{ "24c256", AT24_DEVICE_MAGIC(262144 / 8, AT24_FLAG_ADDR16) },
{ "24c512", AT24_DEVICE_MAGIC(524288 / 8, AT24_FLAG_ADDR16) },
{ "24c1024", AT24_DEVICE_MAGIC(1048576 / 8, AT24_FLAG_ADDR16) },
{ "at24", 0 },
{ /* END OF LIST */ }
};
MODULE_DEVICE_TABLE(i2c, at24_ids);
/*-------------------------------------------------------------------------*/
/*
* This routine supports chips which consume multiple I2C addresses. It
* computes the addressing information to be used for a given r/w request.
* Assumes that sanity checks for offset happened at sysfs-layer.
*/
static struct i2c_client *at24_translate_offset(struct at24_data *at24,
unsigned *offset)
{
unsigned i;
if (at24->chip.flags & AT24_FLAG_ADDR16) {
i = *offset >> 16;
*offset &= 0xffff;
} else {
i = *offset >> 8;
*offset &= 0xff;
}
return at24->client[i];
}
static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
unsigned offset, size_t count)
{
struct i2c_msg msg[2];
u8 msgbuf[2];
struct i2c_client *client;
unsigned long timeout, read_time;
int status, i;
memset(msg, 0, sizeof(msg));
/*
* REVISIT some multi-address chips don't rollover page reads to
* the next slave address, so we may need to truncate the count.
* Those chips might need another quirk flag.
*
* If the real hardware used four adjacent 24c02 chips and that
* were misconfigured as one 24c08, that would be a similar effect:
* one "eeprom" file not four, but larger reads would fail when
* they crossed certain pages.
*/
/*
* Slave address and byte offset derive from the offset. Always
* set the byte address; on a multi-master board, another master
* may have changed the chip's "current" address pointer.
*/
client = at24_translate_offset(at24, &offset);
if (count > io_limit)
count = io_limit;
switch (at24->use_smbus) {
case I2C_SMBUS_I2C_BLOCK_DATA:
/* Smaller eeproms can work given some SMBus extension calls */
if (count > I2C_SMBUS_BLOCK_MAX)
count = I2C_SMBUS_BLOCK_MAX;
break;
case I2C_SMBUS_WORD_DATA:
count = 2;
break;
case I2C_SMBUS_BYTE_DATA:
count = 1;
break;
default:
/*
* When we have a better choice than SMBus calls, use a
* combined I2C message. Write address; then read up to
* io_limit data bytes. Note that read page rollover helps us
* here (unlike writes). msgbuf is u8 and will cast to our
* needs.
*/
i = 0;
if (at24->chip.flags & AT24_FLAG_ADDR16)
msgbuf[i++] = offset >> 8;
msgbuf[i++] = offset;
msg[0].addr = client->addr;
msg[0].buf = msgbuf;
msg[0].len = i;
msg[1].addr = client->addr;
msg[1].flags = I2C_M_RD;
msg[1].buf = buf;
msg[1].len = count;
}
/*
* Reads fail if the previous write didn't complete yet. We may
* loop a few times until this one succeeds, waiting at least
* long enough for one entire page write to work.
*/
timeout = jiffies + msecs_to_jiffies(write_timeout);
do {
read_time = jiffies;
switch (at24->use_smbus) {
case I2C_SMBUS_I2C_BLOCK_DATA:
status = i2c_smbus_read_i2c_block_data(client, offset,
count, buf);
break;
case I2C_SMBUS_WORD_DATA:
status = i2c_smbus_read_word_data(client, offset);
if (status >= 0) {
buf[0] = status & 0xff;
buf[1] = status >> 8;
status = count;
}
break;
case I2C_SMBUS_BYTE_DATA:
status = i2c_smbus_read_byte_data(client, offset);
if (status >= 0) {
buf[0] = status;
status = count;
}
break;
default:
status = i2c_transfer(client->adapter, msg, 2);
if (status == 2)
status = count;
}
dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
count, offset, status, jiffies);
if (status == count)
return count;
/* REVISIT: at HZ=100, this is sloooow */
msleep(1);
} while (time_before(read_time, timeout));
return -ETIMEDOUT;
}
static ssize_t at24_read(struct at24_data *at24,
char *buf, loff_t off, size_t count)
{
ssize_t retval = 0;
if (unlikely(!count))
return count;
/*
* Read data from chip, protecting against concurrent updates
* from this host, but not from other I2C masters.
*/
mutex_lock(&at24->lock);
while (count) {
ssize_t status;
status = at24_eeprom_read(at24, buf, off, count);
if (status <= 0) {
if (retval == 0)
retval = status;
break;
}
buf += status;
off += status;
count -= status;
retval += status;
}
mutex_unlock(&at24->lock);
return retval;
}
static ssize_t at24_bin_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct at24_data *at24;
at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
return at24_read(at24, buf, off, count);
}
/*
* Note that if the hardware write-protect pin is pulled high, the whole
* chip is normally write protected. But there are plenty of product
* variants here, including OTP fuses and partial chip protect.
*
* We only use page mode writes; the alternative is sloooow. This routine
* writes at most one page.
*/
static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
unsigned offset, size_t count)
{
struct i2c_client *client;
struct i2c_msg msg;
ssize_t status;
unsigned long timeout, write_time;
unsigned next_page;
/* Get corresponding I2C address and adjust offset */
client = at24_translate_offset(at24, &offset);
/* write_max is at most a page */
if (count > at24->write_max)
count = at24->write_max;
/* Never roll over backwards, to the start of this page */
next_page = roundup(offset + 1, at24->chip.page_size);
if (offset + count > next_page)
count = next_page - offset;
/* If we'll use I2C calls for I/O, set up the message */
if (!at24->use_smbus) {
int i = 0;
msg.addr = client->addr;
msg.flags = 0;
/* msg.buf is u8 and casts will mask the values */
msg.buf = at24->writebuf;
if (at24->chip.flags & AT24_FLAG_ADDR16)
msg.buf[i++] = offset >> 8;
msg.buf[i++] = offset;
memcpy(&msg.buf[i], buf, count);
msg.len = i + count;
}
/*
* Writes fail if the previous one didn't complete yet. We may
* loop a few times until this one succeeds, waiting at least
* long enough for one entire page write to work.
*/
timeout = jiffies + msecs_to_jiffies(write_timeout);
do {
write_time = jiffies;
if (at24->use_smbus) {
status = i2c_smbus_write_i2c_block_data(client,
offset, count, buf);
if (status == 0)
status = count;
} else {
status = i2c_transfer(client->adapter, &msg, 1);
if (status == 1)
status = count;
}
dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",
count, offset, status, jiffies);
if (status == count)
return count;
/* REVISIT: at HZ=100, this is sloooow */
msleep(1);
} while (time_before(write_time, timeout));
return -ETIMEDOUT;
}
static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off,
size_t count)
{
ssize_t retval = 0;
if (unlikely(!count))
return count;
/*
* Write data to chip, protecting against concurrent updates
* from this host, but not from other I2C masters.
*/
mutex_lock(&at24->lock);
while (count) {
ssize_t status;
status = at24_eeprom_write(at24, buf, off, count);
if (status <= 0) {
if (retval == 0)
retval = status;
break;
}
buf += status;
off += status;
count -= status;
retval += status;
}
mutex_unlock(&at24->lock);
return retval;
}
static ssize_t at24_bin_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct at24_data *at24;
at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
return at24_write(at24, buf, off, count);
}
/*-------------------------------------------------------------------------*/
/*
* This lets other kernel code access the eeprom data. For example, it
* might hold a board's Ethernet address, or board-specific calibration
* data generated on the manufacturing floor.
*/
static ssize_t at24_macc_read(struct memory_accessor *macc, char *buf,
off_t offset, size_t count)
{
struct at24_data *at24 = container_of(macc, struct at24_data, macc);
return at24_read(at24, buf, offset, count);
}
static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf,
off_t offset, size_t count)
{
struct at24_data *at24 = container_of(macc, struct at24_data, macc);
return at24_write(at24, buf, offset, count);
}
/*-------------------------------------------------------------------------*/
#ifdef CONFIG_OF
static void at24_get_ofdata(struct i2c_client *client,
struct at24_platform_data *chip)
{
const __be32 *val;
struct device_node *node = client->dev.of_node;
if (node) {
if (of_get_property(node, "read-only", NULL))
chip->flags |= AT24_FLAG_READONLY;
val = of_get_property(node, "pagesize", NULL);
if (val)
chip->page_size = be32_to_cpup(val);
}
}
#else
static void at24_get_ofdata(struct i2c_client *client,
struct at24_platform_data *chip)
{ }
#endif /* CONFIG_OF */
static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct at24_platform_data chip;
bool writable;
int use_smbus = 0;
struct at24_data *at24;
int err;
unsigned i, num_addresses;
kernel_ulong_t magic;
if (client->dev.platform_data) {
chip = *(struct at24_platform_data *)client->dev.platform_data;
} else {
if (!id->driver_data) {
err = -ENODEV;
goto err_out;
}
magic = id->driver_data;
chip.byte_len = BIT(magic & AT24_BITMASK(AT24_SIZE_BYTELEN));
magic >>= AT24_SIZE_BYTELEN;
chip.flags = magic & AT24_BITMASK(AT24_SIZE_FLAGS);
/*
* This is slow, but we can't know all eeproms, so we better
* play safe. Specifying custom eeprom-types via platform_data
* is recommended anyhow.
*/
chip.page_size = 1;
/* update chipdata if OF is present */
at24_get_ofdata(client, &chip);
chip.setup = NULL;
chip.context = NULL;
}
if (!is_power_of_2(chip.byte_len))
dev_warn(&client->dev,
"byte_len looks suspicious (no power of 2)!\n");
if (!chip.page_size) {
dev_err(&client->dev, "page_size must not be 0!\n");
err = -EINVAL;
goto err_out;
}
if (!is_power_of_2(chip.page_size))
dev_warn(&client->dev,
"page_size looks suspicious (no power of 2)!\n");
/* Use I2C operations unless we're stuck with SMBus extensions. */
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
if (chip.flags & AT24_FLAG_ADDR16) {
err = -EPFNOSUPPORT;
goto err_out;
}
if (i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
use_smbus = I2C_SMBUS_I2C_BLOCK_DATA;
} else if (i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_WORD_DATA)) {
use_smbus = I2C_SMBUS_WORD_DATA;
} else if (i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
use_smbus = I2C_SMBUS_BYTE_DATA;
} else {
err = -EPFNOSUPPORT;
goto err_out;
}
}
if (chip.flags & AT24_FLAG_TAKE8ADDR)
num_addresses = 8;
else
num_addresses = DIV_ROUND_UP(chip.byte_len,
(chip.flags & AT24_FLAG_ADDR16) ? 65536 : 256);
at24 = kzalloc(sizeof(struct at24_data) +
num_addresses * sizeof(struct i2c_client *), GFP_KERNEL);
if (!at24) {
err = -ENOMEM;
goto err_out;
}
mutex_init(&at24->lock);
at24->use_smbus = use_smbus;
at24->chip = chip;
at24->num_addresses = num_addresses;
/*
* Export the EEPROM bytes through sysfs, since that's convenient.
* By default, only root should see the data (maybe passwords etc)
*/
sysfs_bin_attr_init(&at24->bin);
at24->bin.attr.name = "eeprom";
at24->bin.attr.mode = chip.flags & AT24_FLAG_IRUGO ? S_IRUGO : S_IRUSR;
at24->bin.read = at24_bin_read;
at24->bin.size = chip.byte_len;
at24->macc.read = at24_macc_read;
writable = !(chip.flags & AT24_FLAG_READONLY);
if (writable) {
if (!use_smbus || i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
unsigned write_max = chip.page_size;
at24->macc.write = at24_macc_write;
at24->bin.write = at24_bin_write;
at24->bin.attr.mode |= S_IWUSR;
if (write_max > io_limit)
write_max = io_limit;
if (use_smbus && write_max > I2C_SMBUS_BLOCK_MAX)
write_max = I2C_SMBUS_BLOCK_MAX;
at24->write_max = write_max;
/* buffer (data + address at the beginning) */
at24->writebuf = kmalloc(write_max + 2, GFP_KERNEL);
if (!at24->writebuf) {
err = -ENOMEM;
goto err_struct;
}
} else {
dev_warn(&client->dev,
"cannot write due to controller restrictions.");
}
}
at24->client[0] = client;
/* use dummy devices for multiple-address chips */
for (i = 1; i < num_addresses; i++) {
at24->client[i] = i2c_new_dummy(client->adapter,
client->addr + i);
if (!at24->client[i]) {
dev_err(&client->dev, "address 0x%02x unavailable\n",
client->addr + i);
err = -EADDRINUSE;
goto err_clients;
}
}
err = sysfs_create_bin_file(&client->dev.kobj, &at24->bin);
if (err)
goto err_clients;
i2c_set_clientdata(client, at24);
dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
at24->bin.size, client->name,
writable ? "writable" : "read-only", at24->write_max);
if (use_smbus == I2C_SMBUS_WORD_DATA ||
use_smbus == I2C_SMBUS_BYTE_DATA) {
dev_notice(&client->dev, "Falling back to %s reads, "
"performance will suffer\n", use_smbus ==
I2C_SMBUS_WORD_DATA ? "word" : "byte");
}
/* export data to kernel code */
if (chip.setup)
chip.setup(&at24->macc, chip.context);
return 0;
err_clients:
for (i = 1; i < num_addresses; i++)
if (at24->client[i])
i2c_unregister_device(at24->client[i]);
kfree(at24->writebuf);
err_struct:
kfree(at24);
err_out:
dev_dbg(&client->dev, "probe error %d\n", err);
return err;
}
static int __devexit at24_remove(struct i2c_client *client)
{
struct at24_data *at24;
int i;
at24 = i2c_get_clientdata(client);
sysfs_remove_bin_file(&client->dev.kobj, &at24->bin);
for (i = 1; i < at24->num_addresses; i++)
i2c_unregister_device(at24->client[i]);
kfree(at24->writebuf);
kfree(at24);
return 0;
}
/*-------------------------------------------------------------------------*/
static struct i2c_driver at24_driver = {
.driver = {
.name = "at24",
.owner = THIS_MODULE,
},
.probe = at24_probe,
.remove = __devexit_p(at24_remove),
.id_table = at24_ids,
};
static int __init at24_init(void)
{
if (!io_limit) {
pr_err("at24: io_limit must not be 0!\n");
return -EINVAL;
}
io_limit = rounddown_pow_of_two(io_limit);
return i2c_add_driver(&at24_driver);
}
module_init(at24_init);
static void __exit at24_exit(void)
{
i2c_del_driver(&at24_driver);
}
module_exit(at24_exit);
MODULE_DESCRIPTION("Driver for most I2C EEPROMs");
MODULE_AUTHOR("David Brownell and Wolfram Sang");
MODULE_LICENSE("GPL");

413
kernel/drivers/misc/eeprom/at25.c Normal file
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@ -0,0 +1,413 @@
/*
* at25.c -- support most SPI EEPROMs, such as Atmel AT25 models
*
* Copyright (C) 2006 David Brownell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/sched.h>
#include <linux/spi/spi.h>
#include <linux/spi/eeprom.h>
/*
* NOTE: this is an *EEPROM* driver. The vagaries of product naming
* mean that some AT25 products are EEPROMs, and others are FLASH.
* Handle FLASH chips with the drivers/mtd/devices/m25p80.c driver,
* not this one!
*/
struct at25_data {
struct spi_device *spi;
struct memory_accessor mem;
struct mutex lock;
struct spi_eeprom chip;
struct bin_attribute bin;
unsigned addrlen;
};
#define AT25_WREN 0x06 /* latch the write enable */
#define AT25_WRDI 0x04 /* reset the write enable */
#define AT25_RDSR 0x05 /* read status register */
#define AT25_WRSR 0x01 /* write status register */
#define AT25_READ 0x03 /* read byte(s) */
#define AT25_WRITE 0x02 /* write byte(s)/sector */
#define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */
#define AT25_SR_WEN 0x02 /* write enable (latched) */
#define AT25_SR_BP0 0x04 /* BP for software writeprotect */
#define AT25_SR_BP1 0x08
#define AT25_SR_WPEN 0x80 /* writeprotect enable */
#define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */
/* Specs often allow 5 msec for a page write, sometimes 20 msec;
* it's important to recover from write timeouts.
*/
#define EE_TIMEOUT 25
/*-------------------------------------------------------------------------*/
#define io_limit PAGE_SIZE /* bytes */
static ssize_t
at25_ee_read(
struct at25_data *at25,
char *buf,
unsigned offset,
size_t count
)
{
u8 command[EE_MAXADDRLEN + 1];
u8 *cp;
ssize_t status;
struct spi_transfer t[2];
struct spi_message m;
if (unlikely(offset >= at25->bin.size))
return 0;
if ((offset + count) > at25->bin.size)
count = at25->bin.size - offset;
if (unlikely(!count))
return count;
cp = command;
*cp++ = AT25_READ;
/* 8/16/24-bit address is written MSB first */
switch (at25->addrlen) {
default: /* case 3 */
*cp++ = offset >> 16;
case 2:
*cp++ = offset >> 8;
case 1:
case 0: /* can't happen: for better codegen */
*cp++ = offset >> 0;
}
spi_message_init(&m);
memset(t, 0, sizeof t);
t[0].tx_buf = command;
t[0].len = at25->addrlen + 1;
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = count;
spi_message_add_tail(&t[1], &m);
mutex_lock(&at25->lock);
/* Read it all at once.
*
* REVISIT that's potentially a problem with large chips, if
* other devices on the bus need to be accessed regularly or
* this chip is clocked very slowly
*/
status = spi_sync(at25->spi, &m);
dev_dbg(&at25->spi->dev,
"read %Zd bytes at %d --> %d\n",
count, offset, (int) status);
mutex_unlock(&at25->lock);
return status ? status : count;
}
static ssize_t
at25_bin_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct device *dev;
struct at25_data *at25;
dev = container_of(kobj, struct device, kobj);
at25 = dev_get_drvdata(dev);
return at25_ee_read(at25, buf, off, count);
}
static ssize_t
at25_ee_write(struct at25_data *at25, const char *buf, loff_t off,
size_t count)
{
ssize_t status = 0;
unsigned written = 0;
unsigned buf_size;
u8 *bounce;
if (unlikely(off >= at25->bin.size))
return -EFBIG;
if ((off + count) > at25->bin.size)
count = at25->bin.size - off;
if (unlikely(!count))
return count;
/* Temp buffer starts with command and address */
buf_size = at25->chip.page_size;
if (buf_size > io_limit)
buf_size = io_limit;
bounce = kmalloc(buf_size + at25->addrlen + 1, GFP_KERNEL);
if (!bounce)
return -ENOMEM;
/* For write, rollover is within the page ... so we write at
* most one page, then manually roll over to the next page.
*/
bounce[0] = AT25_WRITE;
mutex_lock(&at25->lock);
do {
unsigned long timeout, retries;
unsigned segment;
unsigned offset = (unsigned) off;
u8 *cp = bounce + 1;
int sr;
*cp = AT25_WREN;
status = spi_write(at25->spi, cp, 1);
if (status < 0) {
dev_dbg(&at25->spi->dev, "WREN --> %d\n",
(int) status);
break;
}
/* 8/16/24-bit address is written MSB first */
switch (at25->addrlen) {
default: /* case 3 */
*cp++ = offset >> 16;
case 2:
*cp++ = offset >> 8;
case 1:
case 0: /* can't happen: for better codegen */
*cp++ = offset >> 0;
}
/* Write as much of a page as we can */
segment = buf_size - (offset % buf_size);
if (segment > count)
segment = count;
memcpy(cp, buf, segment);
status = spi_write(at25->spi, bounce,
segment + at25->addrlen + 1);
dev_dbg(&at25->spi->dev,
"write %u bytes at %u --> %d\n",
segment, offset, (int) status);
if (status < 0)
break;
/* REVISIT this should detect (or prevent) failed writes
* to readonly sections of the EEPROM...
*/
/* Wait for non-busy status */
timeout = jiffies + msecs_to_jiffies(EE_TIMEOUT);
retries = 0;
do {
sr = spi_w8r8(at25->spi, AT25_RDSR);
if (sr < 0 || (sr & AT25_SR_nRDY)) {
dev_dbg(&at25->spi->dev,
"rdsr --> %d (%02x)\n", sr, sr);
/* at HZ=100, this is sloooow */
msleep(1);
continue;
}
if (!(sr & AT25_SR_nRDY))
break;
} while (retries++ < 3 || time_before_eq(jiffies, timeout));
if ((sr < 0) || (sr & AT25_SR_nRDY)) {
dev_err(&at25->spi->dev,
"write %d bytes offset %d, "
"timeout after %u msecs\n",
segment, offset,
jiffies_to_msecs(jiffies -
(timeout - EE_TIMEOUT)));
status = -ETIMEDOUT;
break;
}
off += segment;
buf += segment;
count -= segment;
written += segment;
} while (count > 0);
mutex_unlock(&at25->lock);
kfree(bounce);
return written ? written : status;
}
static ssize_t
at25_bin_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct device *dev;
struct at25_data *at25;
dev = container_of(kobj, struct device, kobj);
at25 = dev_get_drvdata(dev);
return at25_ee_write(at25, buf, off, count);
}
/*-------------------------------------------------------------------------*/
/* Let in-kernel code access the eeprom data. */
static ssize_t at25_mem_read(struct memory_accessor *mem, char *buf,
off_t offset, size_t count)
{
struct at25_data *at25 = container_of(mem, struct at25_data, mem);
return at25_ee_read(at25, buf, offset, count);
}
static ssize_t at25_mem_write(struct memory_accessor *mem, const char *buf,
off_t offset, size_t count)
{
struct at25_data *at25 = container_of(mem, struct at25_data, mem);
return at25_ee_write(at25, buf, offset, count);
}
/*-------------------------------------------------------------------------*/
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
const struct spi_eeprom *chip;
int err;
int sr;
int addrlen;
/* Chip description */
chip = spi->dev.platform_data;
if (!chip) {
dev_dbg(&spi->dev, "no chip description\n");
err = -ENODEV;
goto fail;
}
/* For now we only support 8/16/24 bit addressing */
if (chip->flags & EE_ADDR1)
addrlen = 1;
else if (chip->flags & EE_ADDR2)
addrlen = 2;
else if (chip->flags & EE_ADDR3)
addrlen = 3;
else {
dev_dbg(&spi->dev, "unsupported address type\n");
err = -EINVAL;
goto fail;
}
/* Ping the chip ... the status register is pretty portable,
* unlike probing manufacturer IDs. We do expect that system
* firmware didn't write it in the past few milliseconds!
*/
sr = spi_w8r8(spi, AT25_RDSR);
if (sr < 0 || sr & AT25_SR_nRDY) {
dev_dbg(&spi->dev, "rdsr --> %d (%02x)\n", sr, sr);
err = -ENXIO;
goto fail;
}
if (!(at25 = kzalloc(sizeof *at25, GFP_KERNEL))) {
err = -ENOMEM;
goto fail;
}
mutex_init(&at25->lock);
at25->chip = *chip;
at25->spi = spi_dev_get(spi);
dev_set_drvdata(&spi->dev, at25);
at25->addrlen = addrlen;
/* Export the EEPROM bytes through sysfs, since that's convenient.
* And maybe to other kernel code; it might hold a board's Ethernet
* address, or board-specific calibration data generated on the
* manufacturing floor.
*
* Default to root-only access to the data; EEPROMs often hold data
* that's sensitive for read and/or write, like ethernet addresses,
* security codes, board-specific manufacturing calibrations, etc.
*/
sysfs_bin_attr_init(&at25->bin);
at25->bin.attr.name = "eeprom";
at25->bin.attr.mode = S_IRUSR;
at25->bin.read = at25_bin_read;
at25->mem.read = at25_mem_read;
at25->bin.size = at25->chip.byte_len;
if (!(chip->flags & EE_READONLY)) {
at25->bin.write = at25_bin_write;
at25->bin.attr.mode |= S_IWUSR;
at25->mem.write = at25_mem_write;
}
err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);
if (err)
goto fail;
if (chip->setup)
chip->setup(&at25->mem, chip->context);
dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
(at25->bin.size < 1024)
? at25->bin.size
: (at25->bin.size / 1024),
(at25->bin.size < 1024) ? "Byte" : "KByte",
at25->chip.name,
(chip->flags & EE_READONLY) ? " (readonly)" : "",
at25->chip.page_size);
return 0;
fail:
dev_dbg(&spi->dev, "probe err %d\n", err);
kfree(at25);
return err;
}
static int __devexit at25_remove(struct spi_device *spi)
{
struct at25_data *at25;
at25 = dev_get_drvdata(&spi->dev);
sysfs_remove_bin_file(&spi->dev.kobj, &at25->bin);
kfree(at25);
return 0;
}
/*-------------------------------------------------------------------------*/
static struct spi_driver at25_driver = {
.driver = {
.name = "at25",
.owner = THIS_MODULE,
},
.probe = at25_probe,
.remove = __devexit_p(at25_remove),
};
module_spi_driver(at25_driver);
MODULE_DESCRIPTION("Driver for most SPI EEPROMs");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:at25");

85
kernel/drivers/misc/eeprom/digsy_mtc_eeprom.c Normal file
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@ -0,0 +1,85 @@
/*
* EEPROMs access control driver for display configuration EEPROMs
* on DigsyMTC board.
*
* (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_gpio.h>
#include <linux/eeprom_93xx46.h>
#define GPIO_EEPROM_CLK 216
#define GPIO_EEPROM_CS 210
#define GPIO_EEPROM_DI 217
#define GPIO_EEPROM_DO 249
#define GPIO_EEPROM_OE 255
#define EE_SPI_BUS_NUM 1
static void digsy_mtc_op_prepare(void *p)
{
/* enable */
gpio_set_value(GPIO_EEPROM_OE, 0);
}
static void digsy_mtc_op_finish(void *p)
{
/* disable */
gpio_set_value(GPIO_EEPROM_OE, 1);
}
struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
.flags = EE_ADDR8,
.prepare = digsy_mtc_op_prepare,
.finish = digsy_mtc_op_finish,
};
static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
.sck = GPIO_EEPROM_CLK,
.mosi = GPIO_EEPROM_DI,
.miso = GPIO_EEPROM_DO,
.num_chipselect = 1,
};
static struct platform_device digsy_mtc_eeprom = {
.name = "spi_gpio",
.id = EE_SPI_BUS_NUM,
.dev = {
.platform_data = &eeprom_spi_gpio_data,
},
};
static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
{
.modalias = "93xx46",
.max_speed_hz = 1000000,
.bus_num = EE_SPI_BUS_NUM,
.chip_select = 0,
.mode = SPI_MODE_0,
.controller_data = (void *)GPIO_EEPROM_CS,
.platform_data = &digsy_mtc_eeprom_data,
},
};
static int __init digsy_mtc_eeprom_devices_init(void)
{
int ret;
ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
"93xx46 EEPROMs OE");
if (ret) {
pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
return ret;
}
spi_register_board_info(digsy_mtc_eeprom_info,
ARRAY_SIZE(digsy_mtc_eeprom_info));
return platform_device_register(&digsy_mtc_eeprom);
}
device_initcall(digsy_mtc_eeprom_devices_init);

238
kernel/drivers/misc/eeprom/eeprom.c Normal file
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@ -0,0 +1,238 @@
/*
* Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
* Philip Edelbrock <phil@netroedge.com>
* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2003 IBM Corp.
* Copyright (C) 2004 Jean Delvare <khali@linux-fr.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
0x55, 0x56, 0x57, I2C_CLIENT_END };
/* Size of EEPROM in bytes */
#define EEPROM_SIZE 256
/* possible types of eeprom devices */
enum eeprom_nature {
UNKNOWN,
VAIO,
};
/* Each client has this additional data */
struct eeprom_data {
struct mutex update_lock;
u8 valid; /* bitfield, bit!=0 if slice is valid */
unsigned long last_updated[8]; /* In jiffies, 8 slices */
u8 data[EEPROM_SIZE]; /* Register values */
enum eeprom_nature nature;
};
static void eeprom_update_client(struct i2c_client *client, u8 slice)
{
struct eeprom_data *data = i2c_get_clientdata(client);
int i;
mutex_lock(&data->update_lock);
if (!(data->valid & (1 << slice)) ||
time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
for (i = slice << 5; i < (slice + 1) << 5; i += 32)
if (i2c_smbus_read_i2c_block_data(client, i,
32, data->data + i)
!= 32)
goto exit;
} else {
for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
int word = i2c_smbus_read_word_data(client, i);
if (word < 0)
goto exit;
data->data[i] = word & 0xff;
data->data[i + 1] = word >> 8;
}
}
data->last_updated[slice] = jiffies;
data->valid |= (1 << slice);
}
exit:
mutex_unlock(&data->update_lock);
}
static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
struct eeprom_data *data = i2c_get_clientdata(client);
u8 slice;
if (off > EEPROM_SIZE)
return 0;
if (off + count > EEPROM_SIZE)
count = EEPROM_SIZE - off;
/* Only refresh slices which contain requested bytes */
for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
eeprom_update_client(client, slice);
/* Hide Vaio private settings to regular users:
- BIOS passwords: bytes 0x00 to 0x0f
- UUID: bytes 0x10 to 0x1f
- Serial number: 0xc0 to 0xdf */
if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
int i;
for (i = 0; i < count; i++) {
if ((off + i <= 0x1f) ||
(off + i >= 0xc0 && off + i <= 0xdf))
buf[i] = 0;
else
buf[i] = data->data[off + i];
}
} else {
memcpy(buf, &data->data[off], count);
}
return count;
}
static struct bin_attribute eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO,
},
.size = EEPROM_SIZE,
.read = eeprom_read,
};
/* Return 0 if detection is successful, -ENODEV otherwise */
static int eeprom_detect(struct i2c_client *client, struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
addresses 0x50-0x57, but we only care about 0x50. So decline
attaching to addresses >= 0x51 on DDC buses */
if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
return -ENODEV;
/* There are four ways we can read the EEPROM data:
(1) I2C block reads (faster, but unsupported by most adapters)
(2) Word reads (128% overhead)
(3) Consecutive byte reads (88% overhead, unsafe)
(4) Regular byte data reads (265% overhead)
The third and fourth methods are not implemented by this driver
because all known adapters support one of the first two. */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -ENODEV;
strlcpy(info->type, "eeprom", I2C_NAME_SIZE);
return 0;
}
static int eeprom_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct eeprom_data *data;
int err;
if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
memset(data->data, 0xff, EEPROM_SIZE);
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
data->nature = UNKNOWN;
/* Detect the Vaio nature of EEPROMs.
We use the "PCG-" or "VGN-" prefix as the signature. */
if (client->addr == 0x57
&& i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
char name[4];
name[0] = i2c_smbus_read_byte_data(client, 0x80);
name[1] = i2c_smbus_read_byte_data(client, 0x81);
name[2] = i2c_smbus_read_byte_data(client, 0x82);
name[3] = i2c_smbus_read_byte_data(client, 0x83);
if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
dev_info(&client->dev, "Vaio EEPROM detected, "
"enabling privacy protection\n");
data->nature = VAIO;
}
}
/* create the sysfs eeprom file */
err = sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
if (err)
goto exit_kfree;
return 0;
exit_kfree:
kfree(data);
exit:
return err;
}
static int eeprom_remove(struct i2c_client *client)
{
sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
kfree(i2c_get_clientdata(client));
return 0;
}
static const struct i2c_device_id eeprom_id[] = {
{ "eeprom", 0 },
{ }
};
static struct i2c_driver eeprom_driver = {
.driver = {
.name = "eeprom",
},
.probe = eeprom_probe,
.remove = eeprom_remove,
.id_table = eeprom_id,
.class = I2C_CLASS_DDC | I2C_CLASS_SPD,
.detect = eeprom_detect,
.address_list = normal_i2c,
};
module_i2c_driver(eeprom_driver);
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
"Philip Edelbrock <phil@netroedge.com> and "
"Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");

321
kernel/drivers/misc/eeprom/eeprom_93cx6.c Normal file
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@ -0,0 +1,321 @@
/*
* Copyright (C) 2004 - 2006 rt2x00 SourceForge Project
* <http://rt2x00.serialmonkey.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Module: eeprom_93cx6
* Abstract: EEPROM reader routines for 93cx6 chipsets.
* Supported chipsets: 93c46 & 93c66.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/eeprom_93cx6.h>
MODULE_AUTHOR("http://rt2x00.serialmonkey.com");
MODULE_VERSION("1.0");
MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");
MODULE_LICENSE("GPL");
static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)
{
eeprom->reg_data_clock = 1;
eeprom->register_write(eeprom);
/*
* Add a short delay for the pulse to work.
* According to the specifications the "maximum minimum"
* time should be 450ns.
*/
ndelay(450);
}
static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)
{
eeprom->reg_data_clock = 0;
eeprom->register_write(eeprom);
/*
* Add a short delay for the pulse to work.
* According to the specifications the "maximum minimum"
* time should be 450ns.
*/
ndelay(450);
}
static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)
{
/*
* Clear all flags, and enable chip select.
*/
eeprom->register_read(eeprom);
eeprom->reg_data_in = 0;
eeprom->reg_data_out = 0;
eeprom->reg_data_clock = 0;
eeprom->reg_chip_select = 1;
eeprom->drive_data = 1;
eeprom->register_write(eeprom);
/*
* kick a pulse.
*/
eeprom_93cx6_pulse_high(eeprom);
eeprom_93cx6_pulse_low(eeprom);
}
static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)
{
/*
* Clear chip_select and data_in flags.
*/
eeprom->register_read(eeprom);
eeprom->reg_data_in = 0;
eeprom->reg_chip_select = 0;
eeprom->register_write(eeprom);
/*
* kick a pulse.
*/
eeprom_93cx6_pulse_high(eeprom);
eeprom_93cx6_pulse_low(eeprom);
}
static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,
const u16 data, const u16 count)
{
unsigned int i;
eeprom->register_read(eeprom);
/*
* Clear data flags.
*/
eeprom->reg_data_in = 0;
eeprom->reg_data_out = 0;
eeprom->drive_data = 1;
/*
* Start writing all bits.
*/
for (i = count; i > 0; i--) {
/*
* Check if this bit needs to be set.
*/
eeprom->reg_data_in = !!(data & (1 << (i - 1)));
/*
* Write the bit to the eeprom register.
*/
eeprom->register_write(eeprom);
/*
* Kick a pulse.
*/
eeprom_93cx6_pulse_high(eeprom);
eeprom_93cx6_pulse_low(eeprom);
}
eeprom->reg_data_in = 0;
eeprom->register_write(eeprom);
}
static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
u16 *data, const u16 count)
{
unsigned int i;
u16 buf = 0;
eeprom->register_read(eeprom);
/*
* Clear data flags.
*/
eeprom->reg_data_in = 0;
eeprom->reg_data_out = 0;
eeprom->drive_data = 0;
/*
* Start reading all bits.
*/
for (i = count; i > 0; i--) {
eeprom_93cx6_pulse_high(eeprom);
eeprom->register_read(eeprom);
/*
* Clear data_in flag.
*/
eeprom->reg_data_in = 0;
/*
* Read if the bit has been set.
*/
if (eeprom->reg_data_out)
buf |= (1 << (i - 1));
eeprom_93cx6_pulse_low(eeprom);
}
*data = buf;
}
/**
* eeprom_93cx6_read - Read multiple words from eeprom
* @eeprom: Pointer to eeprom structure
* @word: Word index from where we should start reading
* @data: target pointer where the information will have to be stored
*
* This function will read the eeprom data as host-endian word
* into the given data pointer.
*/
void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,
u16 *data)
{
u16 command;
/*
* Initialize the eeprom register
*/
eeprom_93cx6_startup(eeprom);
/*
* Select the read opcode and the word to be read.
*/
command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word;
eeprom_93cx6_write_bits(eeprom, command,
PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
/*
* Read the requested 16 bits.
*/
eeprom_93cx6_read_bits(eeprom, data, 16);
/*
* Cleanup eeprom register.
*/
eeprom_93cx6_cleanup(eeprom);
}
EXPORT_SYMBOL_GPL(eeprom_93cx6_read);
/**
* eeprom_93cx6_multiread - Read multiple words from eeprom
* @eeprom: Pointer to eeprom structure
* @word: Word index from where we should start reading
* @data: target pointer where the information will have to be stored
* @words: Number of words that should be read.
*
* This function will read all requested words from the eeprom,
* this is done by calling eeprom_93cx6_read() multiple times.
* But with the additional change that while the eeprom_93cx6_read
* will return host ordered bytes, this method will return little
* endian words.
*/
void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
__le16 *data, const u16 words)
{
unsigned int i;
u16 tmp;
for (i = 0; i < words; i++) {
tmp = 0;
eeprom_93cx6_read(eeprom, word + i, &tmp);
data[i] = cpu_to_le16(tmp);
}
}
EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);
/**
* eeprom_93cx6_wren - set the write enable state
* @eeprom: Pointer to eeprom structure
* @enable: true to enable writes, otherwise disable writes
*
* Set the EEPROM write enable state to either allow or deny
* writes depending on the @enable value.
*/
void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable)
{
u16 command;
/* start the command */
eeprom_93cx6_startup(eeprom);
/* create command to enable/disable */
command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE;
command <<= (eeprom->width - 2);
eeprom_93cx6_write_bits(eeprom, command,
PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
eeprom_93cx6_cleanup(eeprom);
}
EXPORT_SYMBOL_GPL(eeprom_93cx6_wren);
/**
* eeprom_93cx6_write - write data to the EEPROM
* @eeprom: Pointer to eeprom structure
* @addr: Address to write data to.
* @data: The data to write to address @addr.
*
* Write the @data to the specified @addr in the EEPROM and
* waiting for the device to finish writing.
*
* Note, since we do not expect large number of write operations
* we delay in between parts of the operation to avoid using excessive
* amounts of CPU time busy waiting.
*/
void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data)
{
int timeout = 100;
u16 command;
/* start the command */
eeprom_93cx6_startup(eeprom);
command = PCI_EEPROM_WRITE_OPCODE << eeprom->width;
command |= addr;
/* send write command */
eeprom_93cx6_write_bits(eeprom, command,
PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
/* send data */
eeprom_93cx6_write_bits(eeprom, data, 16);
/* get ready to check for busy */
eeprom->drive_data = 0;
eeprom->reg_chip_select = 1;
eeprom->register_write(eeprom);
/* wait at-least 250ns to get DO to be the busy signal */
usleep_range(1000, 2000);
/* wait for DO to go high to signify finish */
while (true) {
eeprom->register_read(eeprom);
if (eeprom->reg_data_out)
break;
usleep_range(1000, 2000);
if (--timeout <= 0) {
printk(KERN_ERR "%s: timeout\n", __func__);
break;
}
}
eeprom_93cx6_cleanup(eeprom);
}
EXPORT_SYMBOL_GPL(eeprom_93cx6_write);

400
kernel/drivers/misc/eeprom/eeprom_93xx46.c Normal file
View File

@ -0,0 +1,400 @@
/*
* Driver for 93xx46 EEPROMs
*
* (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/eeprom_93xx46.h>
#define OP_START 0x4
#define OP_WRITE (OP_START | 0x1)
#define OP_READ (OP_START | 0x2)
#define ADDR_EWDS 0x00
#define ADDR_ERAL 0x20
#define ADDR_EWEN 0x30
struct eeprom_93xx46_dev {
struct spi_device *spi;
struct eeprom_93xx46_platform_data *pdata;
struct bin_attribute bin;
struct mutex lock;
int addrlen;
};
static ssize_t
eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct eeprom_93xx46_dev *edev;
struct device *dev;
struct spi_message m;
struct spi_transfer t[2];
int bits, ret;
u16 cmd_addr;
dev = container_of(kobj, struct device, kobj);
edev = dev_get_drvdata(dev);
if (unlikely(off >= edev->bin.size))
return 0;
if ((off + count) > edev->bin.size)
count = edev->bin.size - off;
if (unlikely(!count))
return count;
cmd_addr = OP_READ << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= off & 0x7f;
bits = 10;
} else {
cmd_addr |= off & 0x3f;
bits = 9;
}
dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
cmd_addr, edev->spi->max_speed_hz);
spi_message_init(&m);
memset(t, 0, sizeof(t));
t[0].tx_buf = (char *)&cmd_addr;
t[0].len = 2;
t[0].bits_per_word = bits;
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = count;
t[1].bits_per_word = 8;
spi_message_add_tail(&t[1], &m);
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
ret = spi_sync(edev->spi, &m);
/* have to wait at least Tcsl ns */
ndelay(250);
if (ret) {
dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
count, (int)off, ret);
}
if (edev->pdata->finish)
edev->pdata->finish(edev);
mutex_unlock(&edev->lock);
return ret ? : count;
}
static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
{
struct spi_message m;
struct spi_transfer t;
int bits, ret;
u16 cmd_addr;
cmd_addr = OP_START << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
bits = 10;
} else {
cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
bits = 9;
}
dev_dbg(&edev->spi->dev, "ew cmd 0x%04x\n", cmd_addr);
spi_message_init(&m);
memset(&t, 0, sizeof(t));
t.tx_buf = &cmd_addr;
t.len = 2;
t.bits_per_word = bits;
spi_message_add_tail(&t, &m);
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
ret = spi_sync(edev->spi, &m);
/* have to wait at least Tcsl ns */
ndelay(250);
if (ret)
dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
is_on ? "en" : "dis", ret);
if (edev->pdata->finish)
edev->pdata->finish(edev);
mutex_unlock(&edev->lock);
return ret;
}
static ssize_t
eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
const char *buf, unsigned off)
{
struct spi_message m;
struct spi_transfer t[2];
int bits, data_len, ret;
u16 cmd_addr;
cmd_addr = OP_WRITE << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= off & 0x7f;
bits = 10;
data_len = 1;
} else {
cmd_addr |= off & 0x3f;
bits = 9;
data_len = 2;
}
dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
spi_message_init(&m);
memset(t, 0, sizeof(t));
t[0].tx_buf = (char *)&cmd_addr;
t[0].len = 2;
t[0].bits_per_word = bits;
spi_message_add_tail(&t[0], &m);
t[1].tx_buf = buf;
t[1].len = data_len;
t[1].bits_per_word = 8;
spi_message_add_tail(&t[1], &m);
ret = spi_sync(edev->spi, &m);
/* have to wait program cycle time Twc ms */
mdelay(6);
return ret;
}
static ssize_t
eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct eeprom_93xx46_dev *edev;
struct device *dev;
int i, ret, step = 1;
dev = container_of(kobj, struct device, kobj);
edev = dev_get_drvdata(dev);
if (unlikely(off >= edev->bin.size))
return 0;
if ((off + count) > edev->bin.size)
count = edev->bin.size - off;
if (unlikely(!count))
return count;
/* only write even number of bytes on 16-bit devices */
if (edev->addrlen == 6) {
step = 2;
count &= ~1;
}
/* erase/write enable */
ret = eeprom_93xx46_ew(edev, 1);
if (ret)
return ret;
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
for (i = 0; i < count; i += step) {
ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
if (ret) {
dev_err(&edev->spi->dev, "write failed at %d: %d\n",
(int)off + i, ret);
break;
}
}
if (edev->pdata->finish)
edev->pdata->finish(edev);
mutex_unlock(&edev->lock);
/* erase/write disable */
eeprom_93xx46_ew(edev, 0);
return ret ? : count;
}
static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
{
struct eeprom_93xx46_platform_data *pd = edev->pdata;
struct spi_message m;
struct spi_transfer t;
int bits, ret;
u16 cmd_addr;
cmd_addr = OP_START << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= ADDR_ERAL << 1;
bits = 10;
} else {
cmd_addr |= ADDR_ERAL;
bits = 9;
}
spi_message_init(&m);
memset(&t, 0, sizeof(t));
t.tx_buf = &cmd_addr;
t.len = 2;
t.bits_per_word = bits;
spi_message_add_tail(&t, &m);
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
ret = spi_sync(edev->spi, &m);
if (ret)
dev_err(&edev->spi->dev, "erase error %d\n", ret);
/* have to wait erase cycle time Tec ms */
mdelay(6);
if (pd->finish)
pd->finish(edev);
mutex_unlock(&edev->lock);
return ret;
}
static ssize_t eeprom_93xx46_store_erase(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
int erase = 0, ret;
sscanf(buf, "%d", &erase);
if (erase) {
ret = eeprom_93xx46_ew(edev, 1);
if (ret)
return ret;
ret = eeprom_93xx46_eral(edev);
if (ret)
return ret;
ret = eeprom_93xx46_ew(edev, 0);
if (ret)
return ret;
}
return count;
}
static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
static int __devinit eeprom_93xx46_probe(struct spi_device *spi)
{
struct eeprom_93xx46_platform_data *pd;
struct eeprom_93xx46_dev *edev;
int err;
pd = spi->dev.platform_data;
if (!pd) {
dev_err(&spi->dev, "missing platform data\n");
return -ENODEV;
}
edev = kzalloc(sizeof(*edev), GFP_KERNEL);
if (!edev)
return -ENOMEM;
if (pd->flags & EE_ADDR8)
edev->addrlen = 7;
else if (pd->flags & EE_ADDR16)
edev->addrlen = 6;
else {
dev_err(&spi->dev, "unspecified address type\n");
err = -EINVAL;
goto fail;
}
mutex_init(&edev->lock);
edev->spi = spi_dev_get(spi);
edev->pdata = pd;
sysfs_bin_attr_init(&edev->bin);
edev->bin.attr.name = "eeprom";
edev->bin.attr.mode = S_IRUSR;
edev->bin.read = eeprom_93xx46_bin_read;
edev->bin.size = 128;
if (!(pd->flags & EE_READONLY)) {
edev->bin.write = eeprom_93xx46_bin_write;
edev->bin.attr.mode |= S_IWUSR;
}
err = sysfs_create_bin_file(&spi->dev.kobj, &edev->bin);
if (err)
goto fail;
dev_info(&spi->dev, "%d-bit eeprom %s\n",
(pd->flags & EE_ADDR8) ? 8 : 16,
(pd->flags & EE_READONLY) ? "(readonly)" : "");
if (!(pd->flags & EE_READONLY)) {
if (device_create_file(&spi->dev, &dev_attr_erase))
dev_err(&spi->dev, "can't create erase interface\n");
}
dev_set_drvdata(&spi->dev, edev);
return 0;
fail:
kfree(edev);
return err;
}
static int __devexit eeprom_93xx46_remove(struct spi_device *spi)
{
struct eeprom_93xx46_dev *edev = dev_get_drvdata(&spi->dev);
if (!(edev->pdata->flags & EE_READONLY))
device_remove_file(&spi->dev, &dev_attr_erase);
sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin);
dev_set_drvdata(&spi->dev, NULL);
kfree(edev);
return 0;
}
static struct spi_driver eeprom_93xx46_driver = {
.driver = {
.name = "93xx46",
.owner = THIS_MODULE,
},
.probe = eeprom_93xx46_probe,
.remove = __devexit_p(eeprom_93xx46_remove),
};
module_spi_driver(eeprom_93xx46_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
MODULE_ALIAS("spi:93xx46");

215
kernel/drivers/misc/eeprom/max6875.c Normal file
View File

@ -0,0 +1,215 @@
/*
* max6875.c - driver for MAX6874/MAX6875
*
* Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
*
* Based on eeprom.c
*
* The MAX6875 has a bank of registers and two banks of EEPROM.
* Address ranges are defined as follows:
* * 0x0000 - 0x0046 = configuration registers
* * 0x8000 - 0x8046 = configuration EEPROM
* * 0x8100 - 0x82FF = user EEPROM
*
* This driver makes the user EEPROM available for read.
*
* The registers & config EEPROM should be accessed via i2c-dev.
*
* The MAX6875 ignores the lowest address bit, so each chip responds to
* two addresses - 0x50/0x51 and 0x52/0x53.
*
* Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read
* address, so this driver is destructive if loaded for the wrong EEPROM chip.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
/* The MAX6875 can only read/write 16 bytes at a time */
#define SLICE_SIZE 16
#define SLICE_BITS 4
/* USER EEPROM is at addresses 0x8100 - 0x82FF */
#define USER_EEPROM_BASE 0x8100
#define USER_EEPROM_SIZE 0x0200
#define USER_EEPROM_SLICES 32
/* MAX6875 commands */
#define MAX6875_CMD_BLK_READ 0x84
/* Each client has this additional data */
struct max6875_data {
struct i2c_client *fake_client;
struct mutex update_lock;
u32 valid;
u8 data[USER_EEPROM_SIZE];
unsigned long last_updated[USER_EEPROM_SLICES];
};
static void max6875_update_slice(struct i2c_client *client, int slice)
{
struct max6875_data *data = i2c_get_clientdata(client);
int i, j, addr;
u8 *buf;
if (slice >= USER_EEPROM_SLICES)
return;
mutex_lock(&data->update_lock);
buf = &data->data[slice << SLICE_BITS];
if (!(data->valid & (1 << slice)) ||
time_after(jiffies, data->last_updated[slice])) {
dev_dbg(&client->dev, "Starting update of slice %u\n", slice);
data->valid &= ~(1 << slice);
addr = USER_EEPROM_BASE + (slice << SLICE_BITS);
/* select the eeprom address */
if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) {
dev_err(&client->dev, "address set failed\n");
goto exit_up;
}
if (i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
if (i2c_smbus_read_i2c_block_data(client,
MAX6875_CMD_BLK_READ,
SLICE_SIZE,
buf) != SLICE_SIZE) {
goto exit_up;
}
} else {
for (i = 0; i < SLICE_SIZE; i++) {
j = i2c_smbus_read_byte(client);
if (j < 0) {
goto exit_up;
}
buf[i] = j;
}
}
data->last_updated[slice] = jiffies;
data->valid |= (1 << slice);
}
exit_up:
mutex_unlock(&data->update_lock);
}
static ssize_t max6875_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client = kobj_to_i2c_client(kobj);
struct max6875_data *data = i2c_get_clientdata(client);
int slice, max_slice;
if (off > USER_EEPROM_SIZE)
return 0;
if (off + count > USER_EEPROM_SIZE)
count = USER_EEPROM_SIZE - off;
/* refresh slices which contain requested bytes */
max_slice = (off + count - 1) >> SLICE_BITS;
for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++)
max6875_update_slice(client, slice);
memcpy(buf, &data->data[off], count);
return count;
}
static struct bin_attribute user_eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO,
},
.size = USER_EEPROM_SIZE,
.read = max6875_read,
};
static int max6875_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct max6875_data *data;
int err;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA
| I2C_FUNC_SMBUS_READ_BYTE))
return -ENODEV;
/* Only bind to even addresses */
if (client->addr & 1)
return -ENODEV;
if (!(data = kzalloc(sizeof(struct max6875_data), GFP_KERNEL)))
return -ENOMEM;
/* A fake client is created on the odd address */
data->fake_client = i2c_new_dummy(client->adapter, client->addr + 1);
if (!data->fake_client) {
err = -ENOMEM;
goto exit_kfree;
}
/* Init real i2c_client */
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
err = sysfs_create_bin_file(&client->dev.kobj, &user_eeprom_attr);
if (err)
goto exit_remove_fake;
return 0;
exit_remove_fake:
i2c_unregister_device(data->fake_client);
exit_kfree:
kfree(data);
return err;
}
static int max6875_remove(struct i2c_client *client)
{
struct max6875_data *data = i2c_get_clientdata(client);
i2c_unregister_device(data->fake_client);
sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr);
kfree(data);
return 0;
}
static const struct i2c_device_id max6875_id[] = {
{ "max6875", 0 },
{ }
};
static struct i2c_driver max6875_driver = {
.driver = {
.name = "max6875",
},
.probe = max6875_probe,
.remove = max6875_remove,
.id_table = max6875_id,
};
module_i2c_driver(max6875_driver);
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("MAX6875 driver");
MODULE_LICENSE("GPL");