diff options
Diffstat (limited to 'drivers/hwmon/ams/ams-i2c.c')
| -rw-r--r-- | drivers/hwmon/ams/ams-i2c.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/drivers/hwmon/ams/ams-i2c.c b/drivers/hwmon/ams/ams-i2c.c new file mode 100644 index 0000000..2cbf8a6 --- /dev/null +++ b/drivers/hwmon/ams/ams-i2c.c @@ -0,0 +1,275 @@ +/* + * 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[] = { + { "ams", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ams_id); + +static struct i2c_driver ams_i2c_driver = { + .driver = { + .name = "ams", + .owner = THIS_MODULE, + }, + .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) { + /* 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; +} |
