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