278 lines
6.3 KiB
C
278 lines
6.3 KiB
C
/*
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* Apple Motion Sensor driver (I2C variant)
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*
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* Copyright (C) 2005 Stelian Pop (stelian@popies.net)
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* Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
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*
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* Clean room implementation based on the reverse engineered Mac OS X driver by
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* Johannes Berg <johannes@sipsolutions.net>, documentation available at
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* http://johannes.sipsolutions.net/PowerBook/Apple_Motion_Sensor_Specification
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include "ams.h"
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/* AMS registers */
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#define AMS_COMMAND 0x00 /* command register */
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#define AMS_STATUS 0x01 /* status register */
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#define AMS_CTRL1 0x02 /* read control 1 (number of values) */
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#define AMS_CTRL2 0x03 /* read control 2 (offset?) */
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#define AMS_CTRL3 0x04 /* read control 3 (size of each value?) */
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#define AMS_DATA1 0x05 /* read data 1 */
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#define AMS_DATA2 0x06 /* read data 2 */
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#define AMS_DATA3 0x07 /* read data 3 */
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#define AMS_DATA4 0x08 /* read data 4 */
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#define AMS_DATAX 0x20 /* data X */
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#define AMS_DATAY 0x21 /* data Y */
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#define AMS_DATAZ 0x22 /* data Z */
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#define AMS_FREEFALL 0x24 /* freefall int control */
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#define AMS_SHOCK 0x25 /* shock int control */
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#define AMS_SENSLOW 0x26 /* sensitivity low limit */
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#define AMS_SENSHIGH 0x27 /* sensitivity high limit */
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#define AMS_CTRLX 0x28 /* control X */
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#define AMS_CTRLY 0x29 /* control Y */
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#define AMS_CTRLZ 0x2A /* control Z */
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#define AMS_UNKNOWN1 0x2B /* unknown 1 */
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#define AMS_UNKNOWN2 0x2C /* unknown 2 */
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#define AMS_UNKNOWN3 0x2D /* unknown 3 */
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#define AMS_VENDOR 0x2E /* vendor */
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/* AMS commands - use with the AMS_COMMAND register */
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enum ams_i2c_cmd {
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AMS_CMD_NOOP = 0,
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AMS_CMD_VERSION,
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AMS_CMD_READMEM,
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AMS_CMD_WRITEMEM,
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AMS_CMD_ERASEMEM,
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AMS_CMD_READEE,
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AMS_CMD_WRITEEE,
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AMS_CMD_RESET,
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AMS_CMD_START,
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};
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static int ams_i2c_probe(struct i2c_client *client,
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const struct i2c_device_id *id);
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static int ams_i2c_remove(struct i2c_client *client);
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static const struct i2c_device_id ams_id[] = {
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{ "MAC,accelerometer_1", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ams_id);
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static struct i2c_driver ams_i2c_driver = {
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.driver = {
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.name = "ams",
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.owner = THIS_MODULE,
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},
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.probe = ams_i2c_probe,
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.remove = ams_i2c_remove,
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.id_table = ams_id,
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};
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static s32 ams_i2c_read(u8 reg)
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{
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return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
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}
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static int ams_i2c_write(u8 reg, u8 value)
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{
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return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
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}
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static int ams_i2c_cmd(enum ams_i2c_cmd cmd)
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{
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s32 result;
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int count = 3;
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ams_i2c_write(AMS_COMMAND, cmd);
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msleep(5);
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while (count--) {
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result = ams_i2c_read(AMS_COMMAND);
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if (result == 0 || result & 0x80)
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return 0;
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schedule_timeout_uninterruptible(HZ / 20);
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}
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return -1;
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}
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static void ams_i2c_set_irq(enum ams_irq reg, char enable)
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{
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if (reg & AMS_IRQ_FREEFALL) {
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u8 val = ams_i2c_read(AMS_CTRLX);
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if (enable)
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val |= 0x80;
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else
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val &= ~0x80;
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ams_i2c_write(AMS_CTRLX, val);
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}
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if (reg & AMS_IRQ_SHOCK) {
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u8 val = ams_i2c_read(AMS_CTRLY);
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if (enable)
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val |= 0x80;
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else
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val &= ~0x80;
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ams_i2c_write(AMS_CTRLY, val);
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}
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if (reg & AMS_IRQ_GLOBAL) {
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u8 val = ams_i2c_read(AMS_CTRLZ);
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if (enable)
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val |= 0x80;
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else
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val &= ~0x80;
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ams_i2c_write(AMS_CTRLZ, val);
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}
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}
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static void ams_i2c_clear_irq(enum ams_irq reg)
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{
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if (reg & AMS_IRQ_FREEFALL)
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ams_i2c_write(AMS_FREEFALL, 0);
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if (reg & AMS_IRQ_SHOCK)
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ams_i2c_write(AMS_SHOCK, 0);
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}
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static u8 ams_i2c_get_vendor(void)
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{
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return ams_i2c_read(AMS_VENDOR);
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}
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static void ams_i2c_get_xyz(s8 *x, s8 *y, s8 *z)
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{
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*x = ams_i2c_read(AMS_DATAX);
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*y = ams_i2c_read(AMS_DATAY);
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*z = ams_i2c_read(AMS_DATAZ);
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}
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static int ams_i2c_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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int vmaj, vmin;
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int result;
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/* There can be only one */
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if (unlikely(ams_info.has_device))
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return -ENODEV;
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ams_info.i2c_client = client;
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if (ams_i2c_cmd(AMS_CMD_RESET)) {
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printk(KERN_INFO "ams: Failed to reset the device\n");
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return -ENODEV;
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}
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if (ams_i2c_cmd(AMS_CMD_START)) {
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printk(KERN_INFO "ams: Failed to start the device\n");
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return -ENODEV;
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}
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/* get version/vendor information */
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ams_i2c_write(AMS_CTRL1, 0x02);
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ams_i2c_write(AMS_CTRL2, 0x85);
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ams_i2c_write(AMS_CTRL3, 0x01);
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ams_i2c_cmd(AMS_CMD_READMEM);
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vmaj = ams_i2c_read(AMS_DATA1);
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vmin = ams_i2c_read(AMS_DATA2);
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if (vmaj != 1 || vmin != 52) {
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printk(KERN_INFO "ams: Incorrect device version (%d.%d)\n",
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vmaj, vmin);
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return -ENODEV;
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}
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ams_i2c_cmd(AMS_CMD_VERSION);
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vmaj = ams_i2c_read(AMS_DATA1);
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vmin = ams_i2c_read(AMS_DATA2);
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if (vmaj != 0 || vmin != 1) {
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printk(KERN_INFO "ams: Incorrect firmware version (%d.%d)\n",
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vmaj, vmin);
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return -ENODEV;
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}
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/* Disable interrupts */
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ams_i2c_set_irq(AMS_IRQ_ALL, 0);
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result = ams_sensor_attach();
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if (result < 0)
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return result;
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/* Set default values */
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ams_i2c_write(AMS_SENSLOW, 0x15);
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ams_i2c_write(AMS_SENSHIGH, 0x60);
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ams_i2c_write(AMS_CTRLX, 0x08);
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ams_i2c_write(AMS_CTRLY, 0x0F);
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ams_i2c_write(AMS_CTRLZ, 0x4F);
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ams_i2c_write(AMS_UNKNOWN1, 0x14);
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/* Clear interrupts */
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ams_i2c_clear_irq(AMS_IRQ_ALL);
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ams_info.has_device = 1;
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/* Enable interrupts */
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ams_i2c_set_irq(AMS_IRQ_ALL, 1);
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printk(KERN_INFO "ams: Found I2C based motion sensor\n");
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return 0;
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}
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static int ams_i2c_remove(struct i2c_client *client)
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{
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if (ams_info.has_device) {
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ams_sensor_detach();
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/* Disable interrupts */
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ams_i2c_set_irq(AMS_IRQ_ALL, 0);
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/* Clear interrupts */
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ams_i2c_clear_irq(AMS_IRQ_ALL);
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printk(KERN_INFO "ams: Unloading\n");
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ams_info.has_device = 0;
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}
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return 0;
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}
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static void ams_i2c_exit(void)
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{
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i2c_del_driver(&ams_i2c_driver);
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}
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int __init ams_i2c_init(struct device_node *np)
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{
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int result;
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/* Set implementation stuff */
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ams_info.of_node = np;
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ams_info.exit = ams_i2c_exit;
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ams_info.get_vendor = ams_i2c_get_vendor;
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ams_info.get_xyz = ams_i2c_get_xyz;
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ams_info.clear_irq = ams_i2c_clear_irq;
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ams_info.bustype = BUS_I2C;
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result = i2c_add_driver(&ams_i2c_driver);
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return result;
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}
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