1 /* 2 * ADXL345 3-Axis Digital Accelerometer IIO core driver 3 * 4 * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com> 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 * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf 11 */ 12 13 #include <linux/module.h> 14 #include <linux/regmap.h> 15 16 #include <linux/iio/iio.h> 17 #include <linux/iio/sysfs.h> 18 19 #include "adxl345.h" 20 21 #define ADXL345_REG_DEVID 0x00 22 #define ADXL345_REG_OFSX 0x1e 23 #define ADXL345_REG_OFSY 0x1f 24 #define ADXL345_REG_OFSZ 0x20 25 #define ADXL345_REG_OFS_AXIS(index) (ADXL345_REG_OFSX + (index)) 26 #define ADXL345_REG_BW_RATE 0x2C 27 #define ADXL345_REG_POWER_CTL 0x2D 28 #define ADXL345_REG_DATA_FORMAT 0x31 29 #define ADXL345_REG_DATAX0 0x32 30 #define ADXL345_REG_DATAY0 0x34 31 #define ADXL345_REG_DATAZ0 0x36 32 #define ADXL345_REG_DATA_AXIS(index) \ 33 (ADXL345_REG_DATAX0 + (index) * sizeof(__le16)) 34 35 #define ADXL345_BW_RATE GENMASK(3, 0) 36 #define ADXL345_BASE_RATE_NANO_HZ 97656250LL 37 #define NHZ_PER_HZ 1000000000LL 38 39 #define ADXL345_POWER_CTL_MEASURE BIT(3) 40 #define ADXL345_POWER_CTL_STANDBY 0x00 41 42 #define ADXL345_DATA_FORMAT_FULL_RES BIT(3) /* Up to 13-bits resolution */ 43 #define ADXL345_DATA_FORMAT_2G 0 44 #define ADXL345_DATA_FORMAT_4G 1 45 #define ADXL345_DATA_FORMAT_8G 2 46 #define ADXL345_DATA_FORMAT_16G 3 47 48 #define ADXL345_DEVID 0xE5 49 50 /* 51 * In full-resolution mode, scale factor is maintained at ~4 mg/LSB 52 * in all g ranges. 53 * 54 * At +/- 16g with 13-bit resolution, scale is computed as: 55 * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383 56 */ 57 static const int adxl345_uscale = 38300; 58 59 /* 60 * The Datasheet lists a resolution of Resolution is ~49 mg per LSB. That's 61 * ~480mm/s**2 per LSB. 62 */ 63 static const int adxl375_uscale = 480000; 64 65 struct adxl345_data { 66 struct regmap *regmap; 67 u8 data_range; 68 enum adxl345_device_type type; 69 }; 70 71 #define ADXL345_CHANNEL(index, axis) { \ 72 .type = IIO_ACCEL, \ 73 .modified = 1, \ 74 .channel2 = IIO_MOD_##axis, \ 75 .address = index, \ 76 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 77 BIT(IIO_CHAN_INFO_CALIBBIAS), \ 78 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 79 BIT(IIO_CHAN_INFO_SAMP_FREQ), \ 80 } 81 82 static const struct iio_chan_spec adxl345_channels[] = { 83 ADXL345_CHANNEL(0, X), 84 ADXL345_CHANNEL(1, Y), 85 ADXL345_CHANNEL(2, Z), 86 }; 87 88 static int adxl345_read_raw(struct iio_dev *indio_dev, 89 struct iio_chan_spec const *chan, 90 int *val, int *val2, long mask) 91 { 92 struct adxl345_data *data = iio_priv(indio_dev); 93 __le16 accel; 94 long long samp_freq_nhz; 95 unsigned int regval; 96 int ret; 97 98 switch (mask) { 99 case IIO_CHAN_INFO_RAW: 100 /* 101 * Data is stored in adjacent registers: 102 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte 103 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte 104 */ 105 ret = regmap_bulk_read(data->regmap, 106 ADXL345_REG_DATA_AXIS(chan->address), 107 &accel, sizeof(accel)); 108 if (ret < 0) 109 return ret; 110 111 *val = sign_extend32(le16_to_cpu(accel), 12); 112 return IIO_VAL_INT; 113 case IIO_CHAN_INFO_SCALE: 114 *val = 0; 115 switch (data->type) { 116 case ADXL345: 117 *val2 = adxl345_uscale; 118 break; 119 case ADXL375: 120 *val2 = adxl375_uscale; 121 break; 122 } 123 124 return IIO_VAL_INT_PLUS_MICRO; 125 case IIO_CHAN_INFO_CALIBBIAS: 126 ret = regmap_read(data->regmap, 127 ADXL345_REG_OFS_AXIS(chan->address), ®val); 128 if (ret < 0) 129 return ret; 130 /* 131 * 8-bit resolution at +/- 2g, that is 4x accel data scale 132 * factor 133 */ 134 *val = sign_extend32(regval, 7) * 4; 135 136 return IIO_VAL_INT; 137 case IIO_CHAN_INFO_SAMP_FREQ: 138 ret = regmap_read(data->regmap, ADXL345_REG_BW_RATE, ®val); 139 if (ret < 0) 140 return ret; 141 142 samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ << 143 (regval & ADXL345_BW_RATE); 144 *val = div_s64_rem(samp_freq_nhz, NHZ_PER_HZ, val2); 145 146 return IIO_VAL_INT_PLUS_NANO; 147 } 148 149 return -EINVAL; 150 } 151 152 static int adxl345_write_raw(struct iio_dev *indio_dev, 153 struct iio_chan_spec const *chan, 154 int val, int val2, long mask) 155 { 156 struct adxl345_data *data = iio_priv(indio_dev); 157 s64 n; 158 159 switch (mask) { 160 case IIO_CHAN_INFO_CALIBBIAS: 161 /* 162 * 8-bit resolution at +/- 2g, that is 4x accel data scale 163 * factor 164 */ 165 return regmap_write(data->regmap, 166 ADXL345_REG_OFS_AXIS(chan->address), 167 val / 4); 168 case IIO_CHAN_INFO_SAMP_FREQ: 169 n = div_s64(val * NHZ_PER_HZ + val2, ADXL345_BASE_RATE_NANO_HZ); 170 171 return regmap_update_bits(data->regmap, ADXL345_REG_BW_RATE, 172 ADXL345_BW_RATE, 173 clamp_val(ilog2(n), 0, 174 ADXL345_BW_RATE)); 175 } 176 177 return -EINVAL; 178 } 179 180 static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev, 181 struct iio_chan_spec const *chan, 182 long mask) 183 { 184 switch (mask) { 185 case IIO_CHAN_INFO_CALIBBIAS: 186 return IIO_VAL_INT; 187 case IIO_CHAN_INFO_SAMP_FREQ: 188 return IIO_VAL_INT_PLUS_NANO; 189 default: 190 return -EINVAL; 191 } 192 } 193 194 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL( 195 "0.09765625 0.1953125 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200" 196 ); 197 198 static struct attribute *adxl345_attrs[] = { 199 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 200 NULL, 201 }; 202 203 static const struct attribute_group adxl345_attrs_group = { 204 .attrs = adxl345_attrs, 205 }; 206 207 static const struct iio_info adxl345_info = { 208 .attrs = &adxl345_attrs_group, 209 .read_raw = adxl345_read_raw, 210 .write_raw = adxl345_write_raw, 211 .write_raw_get_fmt = adxl345_write_raw_get_fmt, 212 }; 213 214 int adxl345_core_probe(struct device *dev, struct regmap *regmap, 215 enum adxl345_device_type type, const char *name) 216 { 217 struct adxl345_data *data; 218 struct iio_dev *indio_dev; 219 u32 regval; 220 int ret; 221 222 ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val); 223 if (ret < 0) { 224 dev_err(dev, "Error reading device ID: %d\n", ret); 225 return ret; 226 } 227 228 if (regval != ADXL345_DEVID) { 229 dev_err(dev, "Invalid device ID: %x, expected %x\n", 230 regval, ADXL345_DEVID); 231 return -ENODEV; 232 } 233 234 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 235 if (!indio_dev) 236 return -ENOMEM; 237 238 data = iio_priv(indio_dev); 239 dev_set_drvdata(dev, indio_dev); 240 data->regmap = regmap; 241 data->type = type; 242 /* Enable full-resolution mode */ 243 data->data_range = ADXL345_DATA_FORMAT_FULL_RES; 244 245 ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT, 246 data->data_range); 247 if (ret < 0) { 248 dev_err(dev, "Failed to set data range: %d\n", ret); 249 return ret; 250 } 251 252 indio_dev->dev.parent = dev; 253 indio_dev->name = name; 254 indio_dev->info = &adxl345_info; 255 indio_dev->modes = INDIO_DIRECT_MODE; 256 indio_dev->channels = adxl345_channels; 257 indio_dev->num_channels = ARRAY_SIZE(adxl345_channels); 258 259 /* Enable measurement mode */ 260 ret = regmap_write(data->regmap, ADXL345_REG_POWER_CTL, 261 ADXL345_POWER_CTL_MEASURE); 262 if (ret < 0) { 263 dev_err(dev, "Failed to enable measurement mode: %d\n", ret); 264 return ret; 265 } 266 267 ret = iio_device_register(indio_dev); 268 if (ret < 0) { 269 dev_err(dev, "iio_device_register failed: %d\n", ret); 270 regmap_write(data->regmap, ADXL345_REG_POWER_CTL, 271 ADXL345_POWER_CTL_STANDBY); 272 } 273 274 return ret; 275 } 276 EXPORT_SYMBOL_GPL(adxl345_core_probe); 277 278 int adxl345_core_remove(struct device *dev) 279 { 280 struct iio_dev *indio_dev = dev_get_drvdata(dev); 281 struct adxl345_data *data = iio_priv(indio_dev); 282 283 iio_device_unregister(indio_dev); 284 285 return regmap_write(data->regmap, ADXL345_REG_POWER_CTL, 286 ADXL345_POWER_CTL_STANDBY); 287 } 288 EXPORT_SYMBOL_GPL(adxl345_core_remove); 289 290 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>"); 291 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver"); 292 MODULE_LICENSE("GPL v2"); 293