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 14 #include <linux/iio/iio.h> 15 #include <linux/iio/sysfs.h> 16 17 #include "adxl345.h" 18 19 #define ADXL345_REG_DEVID 0x00 20 #define ADXL345_REG_OFSX 0x1e 21 #define ADXL345_REG_OFSY 0x1f 22 #define ADXL345_REG_OFSZ 0x20 23 #define ADXL345_REG_OFS_AXIS(index) (ADXL345_REG_OFSX + (index)) 24 #define ADXL345_REG_BW_RATE 0x2C 25 #define ADXL345_REG_POWER_CTL 0x2D 26 #define ADXL345_REG_DATA_FORMAT 0x31 27 #define ADXL345_REG_DATAX0 0x32 28 #define ADXL345_REG_DATAY0 0x34 29 #define ADXL345_REG_DATAZ0 0x36 30 #define ADXL345_REG_DATA_AXIS(index) \ 31 (ADXL345_REG_DATAX0 + (index) * sizeof(__le16)) 32 33 #define ADXL345_BW_RATE GENMASK(3, 0) 34 #define ADXL345_BASE_RATE_NANO_HZ 97656250LL 35 #define NHZ_PER_HZ 1000000000LL 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, NHZ_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 * NHZ_PER_HZ + val2, ADXL345_BASE_RATE_NANO_HZ); 168 169 return regmap_update_bits(data->regmap, ADXL345_REG_BW_RATE, 170 ADXL345_BW_RATE, 171 clamp_val(ilog2(n), 0, 172 ADXL345_BW_RATE)); 173 } 174 175 return -EINVAL; 176 } 177 178 static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev, 179 struct iio_chan_spec const *chan, 180 long mask) 181 { 182 switch (mask) { 183 case IIO_CHAN_INFO_CALIBBIAS: 184 return IIO_VAL_INT; 185 case IIO_CHAN_INFO_SAMP_FREQ: 186 return IIO_VAL_INT_PLUS_NANO; 187 default: 188 return -EINVAL; 189 } 190 } 191 192 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL( 193 "0.09765625 0.1953125 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200" 194 ); 195 196 static struct attribute *adxl345_attrs[] = { 197 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 198 NULL 199 }; 200 201 static const struct attribute_group adxl345_attrs_group = { 202 .attrs = adxl345_attrs, 203 }; 204 205 static const struct iio_info adxl345_info = { 206 .attrs = &adxl345_attrs_group, 207 .read_raw = adxl345_read_raw, 208 .write_raw = adxl345_write_raw, 209 .write_raw_get_fmt = adxl345_write_raw_get_fmt, 210 }; 211 212 static int adxl345_powerup(void *regmap) 213 { 214 return regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_MEASURE); 215 } 216 217 static void adxl345_powerdown(void *regmap) 218 { 219 regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY); 220 } 221 222 int adxl345_core_probe(struct device *dev, struct regmap *regmap) 223 { 224 enum adxl345_device_type type; 225 struct adxl345_data *data; 226 struct iio_dev *indio_dev; 227 const char *name; 228 u32 regval; 229 int ret; 230 231 type = (uintptr_t)device_get_match_data(dev); 232 switch (type) { 233 case ADXL345: 234 name = "adxl345"; 235 break; 236 case ADXL375: 237 name = "adxl375"; 238 break; 239 default: 240 return -EINVAL; 241 } 242 243 ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val); 244 if (ret < 0) 245 return dev_err_probe(dev, ret, "Error reading device ID\n"); 246 247 if (regval != ADXL345_DEVID) 248 return dev_err_probe(dev, -ENODEV, "Invalid device ID: %x, expected %x\n", 249 regval, ADXL345_DEVID); 250 251 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 252 if (!indio_dev) 253 return -ENOMEM; 254 255 data = iio_priv(indio_dev); 256 data->regmap = regmap; 257 data->type = type; 258 /* Enable full-resolution mode */ 259 data->data_range = ADXL345_DATA_FORMAT_FULL_RES; 260 261 ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT, 262 data->data_range); 263 if (ret < 0) 264 return dev_err_probe(dev, ret, "Failed to set data range\n"); 265 266 indio_dev->name = name; 267 indio_dev->info = &adxl345_info; 268 indio_dev->modes = INDIO_DIRECT_MODE; 269 indio_dev->channels = adxl345_channels; 270 indio_dev->num_channels = ARRAY_SIZE(adxl345_channels); 271 272 /* Enable measurement mode */ 273 ret = adxl345_powerup(data->regmap); 274 if (ret < 0) 275 return dev_err_probe(dev, ret, "Failed to enable measurement mode\n"); 276 277 ret = devm_add_action_or_reset(dev, adxl345_powerdown, data->regmap); 278 if (ret < 0) 279 return ret; 280 281 return devm_iio_device_register(dev, indio_dev); 282 } 283 EXPORT_SYMBOL_NS_GPL(adxl345_core_probe, IIO_ADXL345); 284 285 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>"); 286 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver"); 287 MODULE_LICENSE("GPL v2"); 288