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 { "MAC,accelerometer_1", 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 } 278