1 /** 2 * Sensortek STK8BA50 3-Axis Accelerometer 3 * 4 * Copyright (c) 2015, Intel Corporation. 5 * 6 * This file is subject to the terms and conditions of version 2 of 7 * the GNU General Public License. See the file COPYING in the main 8 * directory of this archive for more details. 9 * 10 * STK8BA50 7-bit I2C address: 0x18. 11 */ 12 13 #include <linux/acpi.h> 14 #include <linux/i2c.h> 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/iio/iio.h> 18 #include <linux/iio/sysfs.h> 19 20 #define STK8BA50_REG_XOUT 0x02 21 #define STK8BA50_REG_YOUT 0x04 22 #define STK8BA50_REG_ZOUT 0x06 23 #define STK8BA50_REG_RANGE 0x0F 24 #define STK8BA50_REG_POWMODE 0x11 25 #define STK8BA50_REG_SWRST 0x14 26 27 #define STK8BA50_MODE_NORMAL 0 28 #define STK8BA50_MODE_SUSPEND 1 29 #define STK8BA50_MODE_POWERBIT BIT(7) 30 #define STK8BA50_DATA_SHIFT 6 31 #define STK8BA50_RESET_CMD 0xB6 32 33 #define STK8BA50_DRIVER_NAME "stk8ba50" 34 35 #define STK8BA50_SCALE_AVAIL "0.0384 0.0767 0.1534 0.3069" 36 37 /* 38 * The accelerometer has four measurement ranges: 39 * +/-2g; +/-4g; +/-8g; +/-16g 40 * 41 * Acceleration values are 10-bit, 2's complement. 42 * Scales are calculated as following: 43 * 44 * scale1 = (2 + 2) * 9.81 / (2^10 - 1) = 0.0384 45 * scale2 = (4 + 4) * 9.81 / (2^10 - 1) = 0.0767 46 * etc. 47 * 48 * Scales are stored in this format: 49 * { <register value>, <scale value> } 50 * 51 * Locally, the range is stored as a table index. 52 */ 53 static const int stk8ba50_scale_table[][2] = { 54 {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900} 55 }; 56 57 struct stk8ba50_data { 58 struct i2c_client *client; 59 struct mutex lock; 60 int range; 61 }; 62 63 #define STK8BA50_ACCEL_CHANNEL(reg, axis) { \ 64 .type = IIO_ACCEL, \ 65 .address = reg, \ 66 .modified = 1, \ 67 .channel2 = IIO_MOD_##axis, \ 68 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 69 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 70 } 71 72 static const struct iio_chan_spec stk8ba50_channels[] = { 73 STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_XOUT, X), 74 STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_YOUT, Y), 75 STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_ZOUT, Z), 76 }; 77 78 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL); 79 80 static struct attribute *stk8ba50_attributes[] = { 81 &iio_const_attr_in_accel_scale_available.dev_attr.attr, 82 NULL, 83 }; 84 85 static const struct attribute_group stk8ba50_attribute_group = { 86 .attrs = stk8ba50_attributes 87 }; 88 89 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg) 90 { 91 int ret; 92 struct i2c_client *client = data->client; 93 94 ret = i2c_smbus_read_word_data(client, reg); 95 if (ret < 0) { 96 dev_err(&client->dev, "register read failed\n"); 97 return ret; 98 } 99 100 return sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9); 101 } 102 103 static int stk8ba50_read_raw(struct iio_dev *indio_dev, 104 struct iio_chan_spec const *chan, 105 int *val, int *val2, long mask) 106 { 107 struct stk8ba50_data *data = iio_priv(indio_dev); 108 109 switch (mask) { 110 case IIO_CHAN_INFO_RAW: 111 mutex_lock(&data->lock); 112 *val = stk8ba50_read_accel(data, chan->address); 113 mutex_unlock(&data->lock); 114 return IIO_VAL_INT; 115 case IIO_CHAN_INFO_SCALE: 116 *val = 0; 117 *val2 = stk8ba50_scale_table[data->range][1]; 118 return IIO_VAL_INT_PLUS_MICRO; 119 } 120 121 return -EINVAL; 122 } 123 124 static int stk8ba50_write_raw(struct iio_dev *indio_dev, 125 struct iio_chan_spec const *chan, 126 int val, int val2, long mask) 127 { 128 int ret; 129 int i; 130 int index = -1; 131 struct stk8ba50_data *data = iio_priv(indio_dev); 132 133 switch (mask) { 134 case IIO_CHAN_INFO_SCALE: 135 if (val != 0) 136 return -EINVAL; 137 138 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++) 139 if (val2 == stk8ba50_scale_table[i][1]) { 140 index = i; 141 break; 142 } 143 if (index < 0) 144 return -EINVAL; 145 146 ret = i2c_smbus_write_byte_data(data->client, 147 STK8BA50_REG_RANGE, 148 stk8ba50_scale_table[index][0]); 149 if (ret < 0) 150 dev_err(&data->client->dev, 151 "failed to set measurement range\n"); 152 else 153 data->range = index; 154 155 return ret; 156 } 157 158 return -EINVAL; 159 } 160 161 static const struct iio_info stk8ba50_info = { 162 .driver_module = THIS_MODULE, 163 .read_raw = stk8ba50_read_raw, 164 .write_raw = stk8ba50_write_raw, 165 .attrs = &stk8ba50_attribute_group, 166 }; 167 168 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode) 169 { 170 int ret; 171 u8 masked_reg; 172 struct i2c_client *client = data->client; 173 174 ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE); 175 if (ret < 0) 176 goto exit_err; 177 178 if (mode) 179 masked_reg = ret | STK8BA50_MODE_POWERBIT; 180 else 181 masked_reg = ret & (~STK8BA50_MODE_POWERBIT); 182 183 ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE, 184 masked_reg); 185 if (ret < 0) 186 goto exit_err; 187 188 return ret; 189 190 exit_err: 191 dev_err(&client->dev, "failed to change sensor mode\n"); 192 return ret; 193 } 194 195 static int stk8ba50_probe(struct i2c_client *client, 196 const struct i2c_device_id *id) 197 { 198 int ret; 199 struct iio_dev *indio_dev; 200 struct stk8ba50_data *data; 201 202 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 203 if (!indio_dev) { 204 dev_err(&client->dev, "iio allocation failed!\n"); 205 return -ENOMEM; 206 } 207 208 data = iio_priv(indio_dev); 209 data->client = client; 210 i2c_set_clientdata(client, indio_dev); 211 mutex_init(&data->lock); 212 213 indio_dev->dev.parent = &client->dev; 214 indio_dev->info = &stk8ba50_info; 215 indio_dev->name = STK8BA50_DRIVER_NAME; 216 indio_dev->modes = INDIO_DIRECT_MODE; 217 indio_dev->channels = stk8ba50_channels; 218 indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels); 219 220 /* Reset all registers on startup */ 221 ret = i2c_smbus_write_byte_data(client, 222 STK8BA50_REG_SWRST, STK8BA50_RESET_CMD); 223 if (ret < 0) { 224 dev_err(&client->dev, "failed to reset sensor\n"); 225 return ret; 226 } 227 228 /* The default range is +/-2g */ 229 data->range = 0; 230 231 ret = iio_device_register(indio_dev); 232 if (ret < 0) { 233 dev_err(&client->dev, "device_register failed\n"); 234 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND); 235 } 236 237 return ret; 238 } 239 240 static int stk8ba50_remove(struct i2c_client *client) 241 { 242 struct iio_dev *indio_dev = i2c_get_clientdata(client); 243 244 iio_device_unregister(indio_dev); 245 246 return stk8ba50_set_power(iio_priv(indio_dev), STK8BA50_MODE_SUSPEND); 247 } 248 249 #ifdef CONFIG_PM_SLEEP 250 static int stk8ba50_suspend(struct device *dev) 251 { 252 struct stk8ba50_data *data; 253 254 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); 255 256 return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND); 257 } 258 259 static int stk8ba50_resume(struct device *dev) 260 { 261 struct stk8ba50_data *data; 262 263 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); 264 265 return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL); 266 } 267 268 static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume); 269 270 #define STK8BA50_PM_OPS (&stk8ba50_pm_ops) 271 #else 272 #define STK8BA50_PM_OPS NULL 273 #endif 274 275 static const struct i2c_device_id stk8ba50_i2c_id[] = { 276 {"stk8ba50", 0}, 277 {} 278 }; 279 280 static const struct acpi_device_id stk8ba50_acpi_id[] = { 281 {"STK8BA50", 0}, 282 {} 283 }; 284 285 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id); 286 287 static struct i2c_driver stk8ba50_driver = { 288 .driver = { 289 .name = "stk8ba50", 290 .pm = STK8BA50_PM_OPS, 291 .acpi_match_table = ACPI_PTR(stk8ba50_acpi_id), 292 }, 293 .probe = stk8ba50_probe, 294 .remove = stk8ba50_remove, 295 .id_table = stk8ba50_i2c_id, 296 }; 297 298 module_i2c_driver(stk8ba50_driver); 299 300 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>"); 301 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver"); 302 MODULE_LICENSE("GPL v2"); 303