drivers/hwmon/ams/ams-i2c.c

   1 /*
   2  * Apple Motion Sensor driver (I2C variant)
   3  *
   4  * Copyright (C) 2005 Stelian Pop (stelian@popies.net)
   5  * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
   6  *
   7  * Clean room implementation based on the reverse engineered Mac OS X driver by
   8  * Johannes Berg <johannes@sipsolutions.net>, documentation available at
   9  * http://johannes.sipsolutions.net/PowerBook/Apple_Motion_Sensor_Specification
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/errno.h>
  20 #include <linux/init.h>
  21 #include <linux/delay.h>
  22
  23 #include "ams.h"
  24
  25 /* AMS registers */
  26 #define AMS_COMMAND     0x00    /* command register */
  27 #define AMS_STATUS      0x01    /* status register */
  28 #define AMS_CTRL1       0x02    /* read control 1 (number of values) */
  29 #define AMS_CTRL2       0x03    /* read control 2 (offset?) */
  30 #define AMS_CTRL3       0x04    /* read control 3 (size of each value?) */
  31 #define AMS_DATA1       0x05    /* read data 1 */
  32 #define AMS_DATA2       0x06    /* read data 2 */
  33 #define AMS_DATA3       0x07    /* read data 3 */
  34 #define AMS_DATA4       0x08    /* read data 4 */
  35 #define AMS_DATAX       0x20    /* data X */
  36 #define AMS_DATAY       0x21    /* data Y */
  37 #define AMS_DATAZ       0x22    /* data Z */
  38 #define AMS_FREEFALL    0x24    /* freefall int control */
  39 #define AMS_SHOCK       0x25    /* shock int control */
  40 #define AMS_SENSLOW     0x26    /* sensitivity low limit */
  41 #define AMS_SENSHIGH    0x27    /* sensitivity high limit */
  42 #define AMS_CTRLX       0x28    /* control X */
  43 #define AMS_CTRLY       0x29    /* control Y */
  44 #define AMS_CTRLZ       0x2A    /* control Z */
  45 #define AMS_UNKNOWN1    0x2B    /* unknown 1 */
  46 #define AMS_UNKNOWN2    0x2C    /* unknown 2 */
  47 #define AMS_UNKNOWN3    0x2D    /* unknown 3 */
  48 #define AMS_VENDOR      0x2E    /* vendor */
  49
  50 /* AMS commands - use with the AMS_COMMAND register */
  51 enum ams_i2c_cmd {
  52         AMS_CMD_NOOP = 0,
  53         AMS_CMD_VERSION,
  54         AMS_CMD_READMEM,
  55         AMS_CMD_WRITEMEM,
  56         AMS_CMD_ERASEMEM,
  57         AMS_CMD_READEE,
  58         AMS_CMD_WRITEEE,
  59         AMS_CMD_RESET,
  60         AMS_CMD_START,
  61 };
  62
  63 static int ams_i2c_probe(struct i2c_client *client,
  64                          const struct i2c_device_id *id);
  65 static int ams_i2c_remove(struct i2c_client *client);
  66
  67 static const struct i2c_device_id ams_id[] = {
  68         { "ams", 0 },
  69         { }
  70 };
  71 MODULE_DEVICE_TABLE(i2c, ams_id);
  72
  73 static struct i2c_driver ams_i2c_driver = {
  74         .driver = {
  75                 .name   = "ams",
  76                 .owner  = THIS_MODULE,
  77         },
  78         .probe          = ams_i2c_probe,
  79         .remove         = ams_i2c_remove,
  80         .id_table       = ams_id,
  81 };
  82
  83 static s32 ams_i2c_read(u8 reg)
  84 {
  85         return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
  86 }
  87
  88 static int ams_i2c_write(u8 reg, u8 value)
  89 {
  90         return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
  91 }
  92
  93 static int ams_i2c_cmd(enum ams_i2c_cmd cmd)
  94 {
  95         s32 result;
  96         int count = 3;
  97
  98         ams_i2c_write(AMS_COMMAND, cmd);
  99         msleep(5);
 100
 101         while (count--) {
 102                 result = ams_i2c_read(AMS_COMMAND);
 103                 if (result == 0 || result & 0x80)
 104                         return 0;
 105
 106                 schedule_timeout_uninterruptible(HZ / 20);
 107         }
 108
 109         return -1;
 110 }
 111
 112 static void ams_i2c_set_irq(enum ams_irq reg, char enable)
 113 {
 114         if (reg & AMS_IRQ_FREEFALL) {
 115                 u8 val = ams_i2c_read(AMS_CTRLX);
 116                 if (enable)
 117                         val |= 0x80;
 118                 else
 119                         val &= ~0x80;
 120                 ams_i2c_write(AMS_CTRLX, val);
 121         }
 122
 123         if (reg & AMS_IRQ_SHOCK) {
 124                 u8 val = ams_i2c_read(AMS_CTRLY);
 125                 if (enable)
 126                         val |= 0x80;
 127                 else
 128                         val &= ~0x80;
 129                 ams_i2c_write(AMS_CTRLY, val);
 130         }
 131
 132         if (reg & AMS_IRQ_GLOBAL) {
 133                 u8 val = ams_i2c_read(AMS_CTRLZ);
 134                 if (enable)
 135                         val |= 0x80;
 136                 else
 137                         val &= ~0x80;
 138                 ams_i2c_write(AMS_CTRLZ, val);
 139         }
 140 }
 141
 142 static void ams_i2c_clear_irq(enum ams_irq reg)
 143 {
 144         if (reg & AMS_IRQ_FREEFALL)
 145                 ams_i2c_write(AMS_FREEFALL, 0);
 146
 147         if (reg & AMS_IRQ_SHOCK)
 148                 ams_i2c_write(AMS_SHOCK, 0);
 149 }
 150
 151 static u8 ams_i2c_get_vendor(void)
 152 {
 153         return ams_i2c_read(AMS_VENDOR);
 154 }
 155
 156 static void ams_i2c_get_xyz(s8 *x, s8 *y, s8 *z)
 157 {
 158         *x = ams_i2c_read(AMS_DATAX);
 159         *y = ams_i2c_read(AMS_DATAY);
 160         *z = ams_i2c_read(AMS_DATAZ);
 161 }
 162
 163 static int ams_i2c_probe(struct i2c_client *client,
 164                          const struct i2c_device_id *id)
 165 {
 166         int vmaj, vmin;
 167         int result;
 168
 169         /* There can be only one */
 170         if (unlikely(ams_info.has_device))
 171                 return -ENODEV;
 172
 173         ams_info.i2c_client = client;
 174
 175         if (ams_i2c_cmd(AMS_CMD_RESET)) {
 176                 printk(KERN_INFO "ams: Failed to reset the device\n");
 177                 return -ENODEV;
 178         }
 179
 180         if (ams_i2c_cmd(AMS_CMD_START)) {
 181                 printk(KERN_INFO "ams: Failed to start the device\n");
 182                 return -ENODEV;
 183         }
 184
 185         /* get version/vendor information */
 186         ams_i2c_write(AMS_CTRL1, 0x02);
 187         ams_i2c_write(AMS_CTRL2, 0x85);
 188         ams_i2c_write(AMS_CTRL3, 0x01);
 189
 190         ams_i2c_cmd(AMS_CMD_READMEM);
 191
 192         vmaj = ams_i2c_read(AMS_DATA1);
 193         vmin = ams_i2c_read(AMS_DATA2);
 194         if (vmaj != 1 || vmin != 52) {
 195                 printk(KERN_INFO "ams: Incorrect device version (%d.%d)\n",
 196                         vmaj, vmin);
 197                 return -ENODEV;
 198         }
 199
 200         ams_i2c_cmd(AMS_CMD_VERSION);
 201
 202         vmaj = ams_i2c_read(AMS_DATA1);
 203         vmin = ams_i2c_read(AMS_DATA2);
 204         if (vmaj != 0 || vmin != 1) {
 205                 printk(KERN_INFO "ams: Incorrect firmware version (%d.%d)\n",
 206                         vmaj, vmin);
 207                 return -ENODEV;
 208         }
 209
 210         /* Disable interrupts */
 211         ams_i2c_set_irq(AMS_IRQ_ALL, 0);
 212
 213         result = ams_sensor_attach();
 214         if (result < 0)
 215                 return result;
 216
 217         /* Set default values */
 218         ams_i2c_write(AMS_SENSLOW, 0x15);
 219         ams_i2c_write(AMS_SENSHIGH, 0x60);
 220         ams_i2c_write(AMS_CTRLX, 0x08);
 221         ams_i2c_write(AMS_CTRLY, 0x0F);
 222         ams_i2c_write(AMS_CTRLZ, 0x4F);
 223         ams_i2c_write(AMS_UNKNOWN1, 0x14);
 224
 225         /* Clear interrupts */
 226         ams_i2c_clear_irq(AMS_IRQ_ALL);
 227
 228         ams_info.has_device = 1;
 229
 230         /* Enable interrupts */
 231         ams_i2c_set_irq(AMS_IRQ_ALL, 1);
 232
 233         printk(KERN_INFO "ams: Found I2C based motion sensor\n");
 234
 235         return 0;
 236 }
 237
 238 static int ams_i2c_remove(struct i2c_client *client)
 239 {
 240         if (ams_info.has_device) {
 241                 ams_sensor_detach();
 242
 243                 /* Disable interrupts */
 244                 ams_i2c_set_irq(AMS_IRQ_ALL, 0);
 245
 246                 /* Clear interrupts */
 247                 ams_i2c_clear_irq(AMS_IRQ_ALL);
 248
 249                 printk(KERN_INFO "ams: Unloading\n");
 250
 251                 ams_info.has_device = 0;
 252         }
 253
 254         return 0;
 255 }
 256
 257 static void ams_i2c_exit(void)
 258 {
 259         i2c_del_driver(&ams_i2c_driver);
 260 }
 261
 262 int __init ams_i2c_init(struct device_node *np)
 263 {
 264         int result;
 265
 266         /* Set implementation stuff */
 267         ams_info.of_node = np;
 268         ams_info.exit = ams_i2c_exit;
 269         ams_info.get_vendor = ams_i2c_get_vendor;
 270         ams_info.get_xyz = ams_i2c_get_xyz;
 271         ams_info.clear_irq = ams_i2c_clear_irq;
 272         ams_info.bustype = BUS_I2C;
 273
 274         result = i2c_add_driver(&ams_i2c_driver);
 275
 276         return result;
 277 }