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 const struct i2c_device_id *id); 61 static int ams_i2c_remove(struct i2c_client *client); 62 63 static const struct i2c_device_id ams_id[] = { 64 { "MAC,accelerometer_1", 0 }, 65 { } 66 }; 67 MODULE_DEVICE_TABLE(i2c, ams_id); 68 69 static struct i2c_driver ams_i2c_driver = { 70 .driver = { 71 .name = "ams", 72 }, 73 .probe = ams_i2c_probe, 74 .remove = ams_i2c_remove, 75 .id_table = ams_id, 76 }; 77 78 static s32 ams_i2c_read(u8 reg) 79 { 80 return i2c_smbus_read_byte_data(ams_info.i2c_client, reg); 81 } 82 83 static int ams_i2c_write(u8 reg, u8 value) 84 { 85 return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value); 86 } 87 88 static int ams_i2c_cmd(enum ams_i2c_cmd cmd) 89 { 90 s32 result; 91 int count = 3; 92 93 ams_i2c_write(AMS_COMMAND, cmd); 94 msleep(5); 95 96 while (count--) { 97 result = ams_i2c_read(AMS_COMMAND); 98 if (result == 0 || result & 0x80) 99 return 0; 100 101 schedule_timeout_uninterruptible(HZ / 20); 102 } 103 104 return -1; 105 } 106 107 static void ams_i2c_set_irq(enum ams_irq reg, char enable) 108 { 109 if (reg & AMS_IRQ_FREEFALL) { 110 u8 val = ams_i2c_read(AMS_CTRLX); 111 if (enable) 112 val |= 0x80; 113 else 114 val &= ~0x80; 115 ams_i2c_write(AMS_CTRLX, val); 116 } 117 118 if (reg & AMS_IRQ_SHOCK) { 119 u8 val = ams_i2c_read(AMS_CTRLY); 120 if (enable) 121 val |= 0x80; 122 else 123 val &= ~0x80; 124 ams_i2c_write(AMS_CTRLY, val); 125 } 126 127 if (reg & AMS_IRQ_GLOBAL) { 128 u8 val = ams_i2c_read(AMS_CTRLZ); 129 if (enable) 130 val |= 0x80; 131 else 132 val &= ~0x80; 133 ams_i2c_write(AMS_CTRLZ, val); 134 } 135 } 136 137 static void ams_i2c_clear_irq(enum ams_irq reg) 138 { 139 if (reg & AMS_IRQ_FREEFALL) 140 ams_i2c_write(AMS_FREEFALL, 0); 141 142 if (reg & AMS_IRQ_SHOCK) 143 ams_i2c_write(AMS_SHOCK, 0); 144 } 145 146 static u8 ams_i2c_get_vendor(void) 147 { 148 return ams_i2c_read(AMS_VENDOR); 149 } 150 151 static void ams_i2c_get_xyz(s8 *x, s8 *y, s8 *z) 152 { 153 *x = ams_i2c_read(AMS_DATAX); 154 *y = ams_i2c_read(AMS_DATAY); 155 *z = ams_i2c_read(AMS_DATAZ); 156 } 157 158 static int ams_i2c_probe(struct i2c_client *client, 159 const struct i2c_device_id *id) 160 { 161 int vmaj, vmin; 162 int result; 163 164 /* There can be only one */ 165 if (unlikely(ams_info.has_device)) 166 return -ENODEV; 167 168 ams_info.i2c_client = client; 169 170 if (ams_i2c_cmd(AMS_CMD_RESET)) { 171 printk(KERN_INFO "ams: Failed to reset the device\n"); 172 return -ENODEV; 173 } 174 175 if (ams_i2c_cmd(AMS_CMD_START)) { 176 printk(KERN_INFO "ams: Failed to start the device\n"); 177 return -ENODEV; 178 } 179 180 /* get version/vendor information */ 181 ams_i2c_write(AMS_CTRL1, 0x02); 182 ams_i2c_write(AMS_CTRL2, 0x85); 183 ams_i2c_write(AMS_CTRL3, 0x01); 184 185 ams_i2c_cmd(AMS_CMD_READMEM); 186 187 vmaj = ams_i2c_read(AMS_DATA1); 188 vmin = ams_i2c_read(AMS_DATA2); 189 if (vmaj != 1 || vmin != 52) { 190 printk(KERN_INFO "ams: Incorrect device version (%d.%d)\n", 191 vmaj, vmin); 192 return -ENODEV; 193 } 194 195 ams_i2c_cmd(AMS_CMD_VERSION); 196 197 vmaj = ams_i2c_read(AMS_DATA1); 198 vmin = ams_i2c_read(AMS_DATA2); 199 if (vmaj != 0 || vmin != 1) { 200 printk(KERN_INFO "ams: Incorrect firmware version (%d.%d)\n", 201 vmaj, vmin); 202 return -ENODEV; 203 } 204 205 /* Disable interrupts */ 206 ams_i2c_set_irq(AMS_IRQ_ALL, 0); 207 208 result = ams_sensor_attach(); 209 if (result < 0) 210 return result; 211 212 /* Set default values */ 213 ams_i2c_write(AMS_SENSLOW, 0x15); 214 ams_i2c_write(AMS_SENSHIGH, 0x60); 215 ams_i2c_write(AMS_CTRLX, 0x08); 216 ams_i2c_write(AMS_CTRLY, 0x0F); 217 ams_i2c_write(AMS_CTRLZ, 0x4F); 218 ams_i2c_write(AMS_UNKNOWN1, 0x14); 219 220 /* Clear interrupts */ 221 ams_i2c_clear_irq(AMS_IRQ_ALL); 222 223 ams_info.has_device = 1; 224 225 /* Enable interrupts */ 226 ams_i2c_set_irq(AMS_IRQ_ALL, 1); 227 228 printk(KERN_INFO "ams: Found I2C based motion sensor\n"); 229 230 return 0; 231 } 232 233 static int ams_i2c_remove(struct i2c_client *client) 234 { 235 if (ams_info.has_device) { 236 ams_sensor_detach(); 237 238 /* Disable interrupts */ 239 ams_i2c_set_irq(AMS_IRQ_ALL, 0); 240 241 /* Clear interrupts */ 242 ams_i2c_clear_irq(AMS_IRQ_ALL); 243 244 printk(KERN_INFO "ams: Unloading\n"); 245 246 ams_info.has_device = 0; 247 } 248 249 return 0; 250 } 251 252 static void ams_i2c_exit(void) 253 { 254 i2c_del_driver(&ams_i2c_driver); 255 } 256 257 int __init ams_i2c_init(struct device_node *np) 258 { 259 int result; 260 261 /* Set implementation stuff */ 262 ams_info.of_node = np; 263 ams_info.exit = ams_i2c_exit; 264 ams_info.get_vendor = ams_i2c_get_vendor; 265 ams_info.get_xyz = ams_i2c_get_xyz; 266 ams_info.clear_irq = ams_i2c_clear_irq; 267 ams_info.bustype = BUS_I2C; 268 269 result = i2c_add_driver(&ams_i2c_driver); 270 271 return result; 272 } 273