233 lines
6.1 KiB
C
233 lines
6.1 KiB
C
/*
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* An I2C driver for the NXP PCF2127 RTC
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* Copyright 2013 Til-Technologies
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*
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* Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
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*
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* based on the other drivers in this same directory.
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*
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* http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#define DRV_VERSION "0.0.1"
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#define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */
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#define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */
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#define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */
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#define PCF2127_REG_SC (0x03) /* datetime */
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#define PCF2127_REG_MN (0x04)
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#define PCF2127_REG_HR (0x05)
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#define PCF2127_REG_DM (0x06)
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#define PCF2127_REG_DW (0x07)
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#define PCF2127_REG_MO (0x08)
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#define PCF2127_REG_YR (0x09)
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static struct i2c_driver pcf2127_driver;
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struct pcf2127 {
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struct rtc_device *rtc;
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int voltage_low; /* indicates if a low_voltage was detected */
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};
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/*
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* In the routines that deal directly with the pcf2127 hardware, we use
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* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
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*/
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static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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struct pcf2127 *pcf2127 = i2c_get_clientdata(client);
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unsigned char buf[10] = { PCF2127_REG_CTRL1 };
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/* read registers */
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if (i2c_master_send(client, buf, 1) != 1 ||
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i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) {
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dev_err(&client->dev, "%s: read error\n", __func__);
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return -EIO;
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}
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if (buf[PCF2127_REG_CTRL3] & 0x04) {
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pcf2127->voltage_low = 1;
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dev_info(&client->dev,
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"low voltage detected, date/time is not reliable.\n");
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}
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dev_dbg(&client->dev,
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"%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
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"sec=%02x, min=%02x, hr=%02x, "
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"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
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__func__,
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buf[0], buf[1], buf[2],
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buf[3], buf[4], buf[5],
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buf[6], buf[7], buf[8], buf[9]);
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tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
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tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
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tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
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tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
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tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
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tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
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tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
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if (tm->tm_year < 70)
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tm->tm_year += 100; /* assume we are in 1970...2069 */
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dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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/* the clock can give out invalid datetime, but we cannot return
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* -EINVAL otherwise hwclock will refuse to set the time on bootup.
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*/
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if (rtc_valid_tm(tm) < 0)
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dev_err(&client->dev, "retrieved date/time is not valid.\n");
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return 0;
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}
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static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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unsigned char buf[8];
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int i = 0, err;
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dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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/* start register address */
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buf[i++] = PCF2127_REG_SC;
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/* hours, minutes and seconds */
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buf[i++] = bin2bcd(tm->tm_sec);
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buf[i++] = bin2bcd(tm->tm_min);
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buf[i++] = bin2bcd(tm->tm_hour);
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buf[i++] = bin2bcd(tm->tm_mday);
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buf[i++] = tm->tm_wday & 0x07;
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/* month, 1 - 12 */
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buf[i++] = bin2bcd(tm->tm_mon + 1);
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/* year */
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buf[i++] = bin2bcd(tm->tm_year % 100);
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/* write register's data */
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err = i2c_master_send(client, buf, i);
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if (err != i) {
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dev_err(&client->dev,
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"%s: err=%d", __func__, err);
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return -EIO;
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}
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return 0;
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}
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#ifdef CONFIG_RTC_INTF_DEV
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static int pcf2127_rtc_ioctl(struct device *dev,
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unsigned int cmd, unsigned long arg)
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{
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struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev));
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switch (cmd) {
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case RTC_VL_READ:
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if (pcf2127->voltage_low)
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dev_info(dev, "low voltage detected, date/time is not reliable.\n");
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if (copy_to_user((void __user *)arg, &pcf2127->voltage_low,
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sizeof(int)))
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return -EFAULT;
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return 0;
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default:
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return -ENOIOCTLCMD;
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}
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}
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#else
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#define pcf2127_rtc_ioctl NULL
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#endif
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static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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return pcf2127_get_datetime(to_i2c_client(dev), tm);
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}
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static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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return pcf2127_set_datetime(to_i2c_client(dev), tm);
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}
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static const struct rtc_class_ops pcf2127_rtc_ops = {
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.ioctl = pcf2127_rtc_ioctl,
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.read_time = pcf2127_rtc_read_time,
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.set_time = pcf2127_rtc_set_time,
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};
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static int pcf2127_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct pcf2127 *pcf2127;
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dev_dbg(&client->dev, "%s\n", __func__);
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127),
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GFP_KERNEL);
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if (!pcf2127)
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return -ENOMEM;
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dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
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i2c_set_clientdata(client, pcf2127);
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pcf2127->rtc = devm_rtc_device_register(&client->dev,
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pcf2127_driver.driver.name,
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&pcf2127_rtc_ops, THIS_MODULE);
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return PTR_ERR_OR_ZERO(pcf2127->rtc);
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}
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static const struct i2c_device_id pcf2127_id[] = {
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{ "pcf2127", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, pcf2127_id);
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#ifdef CONFIG_OF
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static const struct of_device_id pcf2127_of_match[] = {
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{ .compatible = "nxp,pcf2127" },
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{}
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};
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MODULE_DEVICE_TABLE(of, pcf2127_of_match);
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#endif
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static struct i2c_driver pcf2127_driver = {
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.driver = {
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.name = "rtc-pcf2127",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(pcf2127_of_match),
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},
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.probe = pcf2127_probe,
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.id_table = pcf2127_id,
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};
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module_i2c_driver(pcf2127_driver);
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MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
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MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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