1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ADXL345 3-Axis Digital Accelerometer IIO core driver 4 * 5 * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com> 6 * 7 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf 8 */ 9 10 #include <linux/module.h> 11 #include <linux/property.h> 12 #include <linux/regmap.h> 13 #include <linux/units.h> 14 15 #include <linux/iio/iio.h> 16 #include <linux/iio/sysfs.h> 17 18 #include "adxl345.h" 19 20 #define ADXL345_REG_DEVID 0x00 21 #define ADXL345_REG_OFSX 0x1e 22 #define ADXL345_REG_OFSY 0x1f 23 #define ADXL345_REG_OFSZ 0x20 24 #define ADXL345_REG_OFS_AXIS(index) (ADXL345_REG_OFSX + (index)) 25 #define ADXL345_REG_BW_RATE 0x2C 26 #define ADXL345_REG_POWER_CTL 0x2D 27 #define ADXL345_REG_DATA_FORMAT 0x31 28 #define ADXL345_REG_DATAX0 0x32 29 #define ADXL345_REG_DATAY0 0x34 30 #define ADXL345_REG_DATAZ0 0x36 31 #define ADXL345_REG_DATA_AXIS(index) \ 32 (ADXL345_REG_DATAX0 + (index) * sizeof(__le16)) 33 34 #define ADXL345_BW_RATE GENMASK(3, 0) 35 #define ADXL345_BASE_RATE_NANO_HZ 97656250LL 36 37 #define ADXL345_POWER_CTL_MEASURE BIT(3) 38 #define ADXL345_POWER_CTL_STANDBY 0x00 39 40 #define ADXL345_DATA_FORMAT_FULL_RES BIT(3) /* Up to 13-bits resolution */ 41 #define ADXL345_DATA_FORMAT_2G 0 42 #define ADXL345_DATA_FORMAT_4G 1 43 #define ADXL345_DATA_FORMAT_8G 2 44 #define ADXL345_DATA_FORMAT_16G 3 45 46 #define ADXL345_DEVID 0xE5 47 48 /* 49 * In full-resolution mode, scale factor is maintained at ~4 mg/LSB 50 * in all g ranges. 51 * 52 * At +/- 16g with 13-bit resolution, scale is computed as: 53 * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383 54 */ 55 static const int adxl345_uscale = 38300; 56 57 /* 58 * The Datasheet lists a resolution of Resolution is ~49 mg per LSB. That's 59 * ~480mm/s**2 per LSB. 60 */ 61 static const int adxl375_uscale = 480000; 62 63 struct adxl345_data { 64 struct regmap *regmap; 65 u8 data_range; 66 enum adxl345_device_type type; 67 }; 68 69 #define ADXL345_CHANNEL(index, axis) { \ 70 .type = IIO_ACCEL, \ 71 .modified = 1, \ 72 .channel2 = IIO_MOD_##axis, \ 73 .address = index, \ 74 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 75 BIT(IIO_CHAN_INFO_CALIBBIAS), \ 76 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 77 BIT(IIO_CHAN_INFO_SAMP_FREQ), \ 78 } 79 80 static const struct iio_chan_spec adxl345_channels[] = { 81 ADXL345_CHANNEL(0, X), 82 ADXL345_CHANNEL(1, Y), 83 ADXL345_CHANNEL(2, Z), 84 }; 85 86 static int adxl345_read_raw(struct iio_dev *indio_dev, 87 struct iio_chan_spec const *chan, 88 int *val, int *val2, long mask) 89 { 90 struct adxl345_data *data = iio_priv(indio_dev); 91 __le16 accel; 92 long long samp_freq_nhz; 93 unsigned int regval; 94 int ret; 95 96 switch (mask) { 97 case IIO_CHAN_INFO_RAW: 98 /* 99 * Data is stored in adjacent registers: 100 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte 101 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte 102 */ 103 ret = regmap_bulk_read(data->regmap, 104 ADXL345_REG_DATA_AXIS(chan->address), 105 &accel, sizeof(accel)); 106 if (ret < 0) 107 return ret; 108 109 *val = sign_extend32(le16_to_cpu(accel), 12); 110 return IIO_VAL_INT; 111 case IIO_CHAN_INFO_SCALE: 112 *val = 0; 113 switch (data->type) { 114 case ADXL345: 115 *val2 = adxl345_uscale; 116 break; 117 case ADXL375: 118 *val2 = adxl375_uscale; 119 break; 120 } 121 122 return IIO_VAL_INT_PLUS_MICRO; 123 case IIO_CHAN_INFO_CALIBBIAS: 124 ret = regmap_read(data->regmap, 125 ADXL345_REG_OFS_AXIS(chan->address), ®val); 126 if (ret < 0) 127 return ret; 128 /* 129 * 8-bit resolution at +/- 2g, that is 4x accel data scale 130 * factor 131 */ 132 *val = sign_extend32(regval, 7) * 4; 133 134 return IIO_VAL_INT; 135 case IIO_CHAN_INFO_SAMP_FREQ: 136 ret = regmap_read(data->regmap, ADXL345_REG_BW_RATE, ®val); 137 if (ret < 0) 138 return ret; 139 140 samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ << 141 (regval & ADXL345_BW_RATE); 142 *val = div_s64_rem(samp_freq_nhz, NANOHZ_PER_HZ, val2); 143 144 return IIO_VAL_INT_PLUS_NANO; 145 } 146 147 return -EINVAL; 148 } 149 150 static int adxl345_write_raw(struct iio_dev *indio_dev, 151 struct iio_chan_spec const *chan, 152 int val, int val2, long mask) 153 { 154 struct adxl345_data *data = iio_priv(indio_dev); 155 s64 n; 156 157 switch (mask) { 158 case IIO_CHAN_INFO_CALIBBIAS: 159 /* 160 * 8-bit resolution at +/- 2g, that is 4x accel data scale 161 * factor 162 */ 163 return regmap_write(data->regmap, 164 ADXL345_REG_OFS_AXIS(chan->address), 165 val / 4); 166 case IIO_CHAN_INFO_SAMP_FREQ: 167 n = div_s64(val * NANOHZ_PER_HZ + val2, 168 ADXL345_BASE_RATE_NANO_HZ); 169 170 return regmap_update_bits(data->regmap, ADXL345_REG_BW_RATE, 171 ADXL345_BW_RATE, 172 clamp_val(ilog2(n), 0, 173 ADXL345_BW_RATE)); 174 } 175 176 return -EINVAL; 177 } 178 179 static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev, 180 struct iio_chan_spec const *chan, 181 long mask) 182 { 183 switch (mask) { 184 case IIO_CHAN_INFO_CALIBBIAS: 185 return IIO_VAL_INT; 186 case IIO_CHAN_INFO_SAMP_FREQ: 187 return IIO_VAL_INT_PLUS_NANO; 188 default: 189 return -EINVAL; 190 } 191 } 192 193 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL( 194 "0.09765625 0.1953125 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200" 195 ); 196 197 static struct attribute *adxl345_attrs[] = { 198 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 199 NULL 200 }; 201 202 static const struct attribute_group adxl345_attrs_group = { 203 .attrs = adxl345_attrs, 204 }; 205 206 static const struct iio_info adxl345_info = { 207 .attrs = &adxl345_attrs_group, 208 .read_raw = adxl345_read_raw, 209 .write_raw = adxl345_write_raw, 210 .write_raw_get_fmt = adxl345_write_raw_get_fmt, 211 }; 212 213 static int adxl345_powerup(void *regmap) 214 { 215 return regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_MEASURE); 216 } 217 218 static void adxl345_powerdown(void *regmap) 219 { 220 regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY); 221 } 222 223 int adxl345_core_probe(struct device *dev, struct regmap *regmap) 224 { 225 enum adxl345_device_type type; 226 struct adxl345_data *data; 227 struct iio_dev *indio_dev; 228 const char *name; 229 u32 regval; 230 int ret; 231 232 type = (uintptr_t)device_get_match_data(dev); 233 switch (type) { 234 case ADXL345: 235 name = "adxl345"; 236 break; 237 case ADXL375: 238 name = "adxl375"; 239 break; 240 default: 241 return -EINVAL; 242 } 243 244 ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val); 245 if (ret < 0) 246 return dev_err_probe(dev, ret, "Error reading device ID\n"); 247 248 if (regval != ADXL345_DEVID) 249 return dev_err_probe(dev, -ENODEV, "Invalid device ID: %x, expected %x\n", 250 regval, ADXL345_DEVID); 251 252 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 253 if (!indio_dev) 254 return -ENOMEM; 255 256 data = iio_priv(indio_dev); 257 data->regmap = regmap; 258 data->type = type; 259 /* Enable full-resolution mode */ 260 data->data_range = ADXL345_DATA_FORMAT_FULL_RES; 261 262 ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT, 263 data->data_range); 264 if (ret < 0) 265 return dev_err_probe(dev, ret, "Failed to set data range\n"); 266 267 indio_dev->name = name; 268 indio_dev->info = &adxl345_info; 269 indio_dev->modes = INDIO_DIRECT_MODE; 270 indio_dev->channels = adxl345_channels; 271 indio_dev->num_channels = ARRAY_SIZE(adxl345_channels); 272 273 /* Enable measurement mode */ 274 ret = adxl345_powerup(data->regmap); 275 if (ret < 0) 276 return dev_err_probe(dev, ret, "Failed to enable measurement mode\n"); 277 278 ret = devm_add_action_or_reset(dev, adxl345_powerdown, data->regmap); 279 if (ret < 0) 280 return ret; 281 282 return devm_iio_device_register(dev, indio_dev); 283 } 284 EXPORT_SYMBOL_NS_GPL(adxl345_core_probe, IIO_ADXL345); 285 286 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>"); 287 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver"); 288 MODULE_LICENSE("GPL v2"); 289