drivers/macintosh/ams/ams-i2c.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Apple Motion Sensor driver (I2C variant)
   4  *
   5  * Copyright (C) 2005 Stelian Pop (stelian@popies.net)
   6  * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
   7  *
   8  * Clean room implementation based on the reverse engineered Mac OS X driver by
   9  * Johannes Berg <johannes@sipsolutions.net>, documentation available at
  10  * http://johannes.sipsolutions.net/PowerBook/Apple_Motion_Sensor_Specification
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/types.h>
  15 #include <linux/errno.h>
  16 #include <linux/init.h>
  17 #include <linux/delay.h>
  18
  19 #include "ams.h"
  20
  21 /* AMS registers */
  22 #define AMS_COMMAND     0x00    /* command register */
  23 #define AMS_STATUS      0x01    /* status register */
  24 #define AMS_CTRL1       0x02    /* read control 1 (number of values) */
  25 #define AMS_CTRL2       0x03    /* read control 2 (offset?) */
  26 #define AMS_CTRL3       0x04    /* read control 3 (size of each value?) */
  27 #define AMS_DATA1       0x05    /* read data 1 */
  28 #define AMS_DATA2       0x06    /* read data 2 */
  29 #define AMS_DATA3       0x07    /* read data 3 */
  30 #define AMS_DATA4       0x08    /* read data 4 */
  31 #define AMS_DATAX       0x20    /* data X */
  32 #define AMS_DATAY       0x21    /* data Y */
  33 #define AMS_DATAZ       0x22    /* data Z */
  34 #define AMS_FREEFALL    0x24    /* freefall int control */
  35 #define AMS_SHOCK       0x25    /* shock int control */
  36 #define AMS_SENSLOW     0x26    /* sensitivity low limit */
  37 #define AMS_SENSHIGH    0x27    /* sensitivity high limit */
  38 #define AMS_CTRLX       0x28    /* control X */
  39 #define AMS_CTRLY       0x29    /* control Y */
  40 #define AMS_CTRLZ       0x2A    /* control Z */
  41 #define AMS_UNKNOWN1    0x2B    /* unknown 1 */
  42 #define AMS_UNKNOWN2    0x2C    /* unknown 2 */
  43 #define AMS_UNKNOWN3    0x2D    /* unknown 3 */
  44 #define AMS_VENDOR      0x2E    /* vendor */
  45
  46 /* AMS commands - use with the AMS_COMMAND register */
  47 enum ams_i2c_cmd {
  48         AMS_CMD_NOOP = 0,
  49         AMS_CMD_VERSION,
  50         AMS_CMD_READMEM,
  51         AMS_CMD_WRITEMEM,
  52         AMS_CMD_ERASEMEM,
  53         AMS_CMD_READEE,
  54         AMS_CMD_WRITEEE,
  55         AMS_CMD_RESET,
  56         AMS_CMD_START,
  57 };
  58
  59 static int ams_i2c_probe(struct i2c_client *client);
  60 static void ams_i2c_remove(struct i2c_client *client);
  61
  62 static const struct i2c_device_id ams_id[] = {
  63         { "MAC,accelerometer_1" },
  64         { }
  65 };
  66 MODULE_DEVICE_TABLE(i2c, ams_id);
  67
  68 static struct i2c_driver ams_i2c_driver = {
  69         .driver = {
  70                 .name   = "ams",
  71         },
  72         .probe          = ams_i2c_probe,
  73         .remove         = ams_i2c_remove,
  74         .id_table       = ams_id,
  75 };
  76
  77 static s32 ams_i2c_read(u8 reg)
  78 {
  79         return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
  80 }
  81
  82 static int ams_i2c_write(u8 reg, u8 value)
  83 {
  84         return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
  85 }
  86
  87 static int ams_i2c_cmd(enum ams_i2c_cmd cmd)
  88 {
  89         s32 result;
  90         int count = 3;
  91
  92         ams_i2c_write(AMS_COMMAND, cmd);
  93         msleep(5);
  94
  95         while (count--) {
  96                 result = ams_i2c_read(AMS_COMMAND);
  97                 if (result == 0 || result & 0x80)
  98                         return 0;
  99
 100                 schedule_timeout_uninterruptible(HZ / 20);
 101         }
 102
 103         return -1;
 104 }
 105
 106 static void ams_i2c_set_irq(enum ams_irq reg, char enable)
 107 {
 108         if (reg & AMS_IRQ_FREEFALL) {
 109                 u8 val = ams_i2c_read(AMS_CTRLX);
 110                 if (enable)
 111                         val |= 0x80;
 112                 else
 113                         val &= ~0x80;
 114                 ams_i2c_write(AMS_CTRLX, val);
 115         }
 116
 117         if (reg & AMS_IRQ_SHOCK) {
 118                 u8 val = ams_i2c_read(AMS_CTRLY);
 119                 if (enable)
 120                         val |= 0x80;
 121                 else
 122                         val &= ~0x80;
 123                 ams_i2c_write(AMS_CTRLY, val);
 124         }
 125
 126         if (reg & AMS_IRQ_GLOBAL) {
 127                 u8 val = ams_i2c_read(AMS_CTRLZ);
 128                 if (enable)
 129                         val |= 0x80;
 130                 else
 131                         val &= ~0x80;
 132                 ams_i2c_write(AMS_CTRLZ, val);
 133         }
 134 }
 135
 136 static void ams_i2c_clear_irq(enum ams_irq reg)
 137 {
 138         if (reg & AMS_IRQ_FREEFALL)
 139                 ams_i2c_write(AMS_FREEFALL, 0);
 140
 141         if (reg & AMS_IRQ_SHOCK)
 142                 ams_i2c_write(AMS_SHOCK, 0);
 143 }
 144
 145 static u8 ams_i2c_get_vendor(void)
 146 {
 147         return ams_i2c_read(AMS_VENDOR);
 148 }
 149
 150 static void ams_i2c_get_xyz(s8 *x, s8 *y, s8 *z)
 151 {
 152         *x = ams_i2c_read(AMS_DATAX);
 153         *y = ams_i2c_read(AMS_DATAY);
 154         *z = ams_i2c_read(AMS_DATAZ);
 155 }
 156
 157 static int ams_i2c_probe(struct i2c_client *client)
 158 {
 159         int vmaj, vmin;
 160         int result;
 161
 162         /* There can be only one */
 163         if (unlikely(ams_info.has_device))
 164                 return -ENODEV;
 165
 166         ams_info.i2c_client = client;
 167
 168         if (ams_i2c_cmd(AMS_CMD_RESET)) {
 169                 printk(KERN_INFO "ams: Failed to reset the device\n");
 170                 return -ENODEV;
 171         }
 172
 173         if (ams_i2c_cmd(AMS_CMD_START)) {
 174                 printk(KERN_INFO "ams: Failed to start the device\n");
 175                 return -ENODEV;
 176         }
 177
 178         /* get version/vendor information */
 179         ams_i2c_write(AMS_CTRL1, 0x02);
 180         ams_i2c_write(AMS_CTRL2, 0x85);
 181         ams_i2c_write(AMS_CTRL3, 0x01);
 182
 183         ams_i2c_cmd(AMS_CMD_READMEM);
 184
 185         vmaj = ams_i2c_read(AMS_DATA1);
 186         vmin = ams_i2c_read(AMS_DATA2);
 187         if (vmaj != 1 || vmin != 52) {
 188                 printk(KERN_INFO "ams: Incorrect device version (%d.%d)\n",
 189                         vmaj, vmin);
 190                 return -ENODEV;
 191         }
 192
 193         ams_i2c_cmd(AMS_CMD_VERSION);
 194
 195         vmaj = ams_i2c_read(AMS_DATA1);
 196         vmin = ams_i2c_read(AMS_DATA2);
 197         if (vmaj != 0 || vmin != 1) {
 198                 printk(KERN_INFO "ams: Incorrect firmware version (%d.%d)\n",
 199                         vmaj, vmin);
 200                 return -ENODEV;
 201         }
 202
 203         /* Disable interrupts */
 204         ams_i2c_set_irq(AMS_IRQ_ALL, 0);
 205
 206         result = ams_sensor_attach();
 207         if (result < 0)
 208                 return result;
 209
 210         /* Set default values */
 211         ams_i2c_write(AMS_SENSLOW, 0x15);
 212         ams_i2c_write(AMS_SENSHIGH, 0x60);
 213         ams_i2c_write(AMS_CTRLX, 0x08);
 214         ams_i2c_write(AMS_CTRLY, 0x0F);
 215         ams_i2c_write(AMS_CTRLZ, 0x4F);
 216         ams_i2c_write(AMS_UNKNOWN1, 0x14);
 217
 218         /* Clear interrupts */
 219         ams_i2c_clear_irq(AMS_IRQ_ALL);
 220
 221         ams_info.has_device = 1;
 222
 223         /* Enable interrupts */
 224         ams_i2c_set_irq(AMS_IRQ_ALL, 1);
 225
 226         printk(KERN_INFO "ams: Found I2C based motion sensor\n");
 227
 228         return 0;
 229 }
 230
 231 static void ams_i2c_remove(struct i2c_client *client)
 232 {
 233         if (ams_info.has_device) {
 234                 ams_sensor_detach();
 235
 236                 /* Disable interrupts */
 237                 ams_i2c_set_irq(AMS_IRQ_ALL, 0);
 238
 239                 /* Clear interrupts */
 240                 ams_i2c_clear_irq(AMS_IRQ_ALL);
 241
 242                 printk(KERN_INFO "ams: Unloading\n");
 243
 244                 ams_info.has_device = 0;
 245         }
 246 }
 247
 248 static void ams_i2c_exit(void)
 249 {
 250         i2c_del_driver(&ams_i2c_driver);
 251 }
 252
 253 int __init ams_i2c_init(struct device_node *np)
 254 {
 255         /* Set implementation stuff */
 256         ams_info.of_node = np;
 257         ams_info.exit = ams_i2c_exit;
 258         ams_info.get_vendor = ams_i2c_get_vendor;
 259         ams_info.get_xyz = ams_i2c_get_xyz;
 260         ams_info.clear_irq = ams_i2c_clear_irq;
 261         ams_info.bustype = BUS_I2C;
 262
 263         return i2c_add_driver(&ams_i2c_driver);
 264 }