1 /* 2 * MS5611 pressure and temperature sensor driver 3 * 4 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Data sheet: 11 * http://www.meas-spec.com/downloads/MS5611-01BA03.pdf 12 * http://www.meas-spec.com/downloads/MS5607-02BA03.pdf 13 * 14 */ 15 16 #include <linux/module.h> 17 #include <linux/iio/iio.h> 18 #include <linux/delay.h> 19 20 #include "ms5611.h" 21 22 static bool ms5611_prom_is_valid(u16 *prom, size_t len) 23 { 24 int i, j; 25 uint16_t crc = 0, crc_orig = prom[7] & 0x000F; 26 27 prom[7] &= 0xFF00; 28 29 for (i = 0; i < len * 2; i++) { 30 if (i % 2 == 1) 31 crc ^= prom[i >> 1] & 0x00FF; 32 else 33 crc ^= prom[i >> 1] >> 8; 34 35 for (j = 0; j < 8; j++) { 36 if (crc & 0x8000) 37 crc = (crc << 1) ^ 0x3000; 38 else 39 crc <<= 1; 40 } 41 } 42 43 crc = (crc >> 12) & 0x000F; 44 45 return crc_orig != 0x0000 && crc == crc_orig; 46 } 47 48 static int ms5611_read_prom(struct iio_dev *indio_dev) 49 { 50 int ret, i; 51 struct ms5611_state *st = iio_priv(indio_dev); 52 53 for (i = 0; i < MS5611_PROM_WORDS_NB; i++) { 54 ret = st->read_prom_word(&indio_dev->dev, 55 i, &st->chip_info->prom[i]); 56 if (ret < 0) { 57 dev_err(&indio_dev->dev, 58 "failed to read prom at %d\n", i); 59 return ret; 60 } 61 } 62 63 if (!ms5611_prom_is_valid(st->chip_info->prom, MS5611_PROM_WORDS_NB)) { 64 dev_err(&indio_dev->dev, "PROM integrity check failed\n"); 65 return -ENODEV; 66 } 67 68 return 0; 69 } 70 71 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev, 72 s32 *temp, s32 *pressure) 73 { 74 int ret; 75 struct ms5611_state *st = iio_priv(indio_dev); 76 77 ret = st->read_adc_temp_and_pressure(&indio_dev->dev, temp, pressure); 78 if (ret < 0) { 79 dev_err(&indio_dev->dev, 80 "failed to read temperature and pressure\n"); 81 return ret; 82 } 83 84 return st->chip_info->temp_and_pressure_compensate(st->chip_info, 85 temp, pressure); 86 } 87 88 static int ms5611_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info, 89 s32 *temp, s32 *pressure) 90 { 91 s32 t = *temp, p = *pressure; 92 s64 off, sens, dt; 93 94 dt = t - (chip_info->prom[5] << 8); 95 off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7); 96 sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8); 97 98 t = 2000 + ((chip_info->prom[6] * dt) >> 23); 99 if (t < 2000) { 100 s64 off2, sens2, t2; 101 102 t2 = (dt * dt) >> 31; 103 off2 = (5 * (t - 2000) * (t - 2000)) >> 1; 104 sens2 = off2 >> 1; 105 106 if (t < -1500) { 107 s64 tmp = (t + 1500) * (t + 1500); 108 109 off2 += 7 * tmp; 110 sens2 += (11 * tmp) >> 1; 111 } 112 113 t -= t2; 114 off -= off2; 115 sens -= sens2; 116 } 117 118 *temp = t; 119 *pressure = (((p * sens) >> 21) - off) >> 15; 120 121 return 0; 122 } 123 124 static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info, 125 s32 *temp, s32 *pressure) 126 { 127 s32 t = *temp, p = *pressure; 128 s64 off, sens, dt; 129 130 dt = t - (chip_info->prom[5] << 8); 131 off = ((s64)chip_info->prom[2] << 17) + ((chip_info->prom[4] * dt) >> 6); 132 sens = ((s64)chip_info->prom[1] << 16) + ((chip_info->prom[3] * dt) >> 7); 133 134 t = 2000 + ((chip_info->prom[6] * dt) >> 23); 135 if (t < 2000) { 136 s64 off2, sens2, t2; 137 138 t2 = (dt * dt) >> 31; 139 off2 = (61 * (t - 2000) * (t - 2000)) >> 4; 140 sens2 = off2 << 1; 141 142 if (t < -1500) { 143 s64 tmp = (t + 1500) * (t + 1500); 144 145 off2 += 15 * tmp; 146 sens2 += (8 * tmp); 147 } 148 149 t -= t2; 150 off -= off2; 151 sens -= sens2; 152 } 153 154 *temp = t; 155 *pressure = (((p * sens) >> 21) - off) >> 15; 156 157 return 0; 158 } 159 160 static int ms5611_reset(struct iio_dev *indio_dev) 161 { 162 int ret; 163 struct ms5611_state *st = iio_priv(indio_dev); 164 165 ret = st->reset(&indio_dev->dev); 166 if (ret < 0) { 167 dev_err(&indio_dev->dev, "failed to reset device\n"); 168 return ret; 169 } 170 171 usleep_range(3000, 4000); 172 173 return 0; 174 } 175 176 static int ms5611_read_raw(struct iio_dev *indio_dev, 177 struct iio_chan_spec const *chan, 178 int *val, int *val2, long mask) 179 { 180 int ret; 181 s32 temp, pressure; 182 struct ms5611_state *st = iio_priv(indio_dev); 183 184 switch (mask) { 185 case IIO_CHAN_INFO_PROCESSED: 186 mutex_lock(&st->lock); 187 ret = ms5611_read_temp_and_pressure(indio_dev, 188 &temp, &pressure); 189 mutex_unlock(&st->lock); 190 if (ret < 0) 191 return ret; 192 193 switch (chan->type) { 194 case IIO_TEMP: 195 *val = temp * 10; 196 return IIO_VAL_INT; 197 case IIO_PRESSURE: 198 *val = pressure / 1000; 199 *val2 = (pressure % 1000) * 1000; 200 return IIO_VAL_INT_PLUS_MICRO; 201 default: 202 return -EINVAL; 203 } 204 } 205 206 return -EINVAL; 207 } 208 209 static struct ms5611_chip_info chip_info_tbl[] = { 210 [MS5611] = { 211 .temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate, 212 }, 213 [MS5607] = { 214 .temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate, 215 } 216 }; 217 218 static const struct iio_chan_spec ms5611_channels[] = { 219 { 220 .type = IIO_PRESSURE, 221 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), 222 }, 223 { 224 .type = IIO_TEMP, 225 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), 226 } 227 }; 228 229 static const struct iio_info ms5611_info = { 230 .read_raw = &ms5611_read_raw, 231 .driver_module = THIS_MODULE, 232 }; 233 234 static int ms5611_init(struct iio_dev *indio_dev) 235 { 236 int ret; 237 238 ret = ms5611_reset(indio_dev); 239 if (ret < 0) 240 return ret; 241 242 return ms5611_read_prom(indio_dev); 243 } 244 245 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev, int type) 246 { 247 int ret; 248 struct ms5611_state *st = iio_priv(indio_dev); 249 250 mutex_init(&st->lock); 251 st->chip_info = &chip_info_tbl[type]; 252 indio_dev->dev.parent = dev; 253 indio_dev->name = dev->driver->name; 254 indio_dev->info = &ms5611_info; 255 indio_dev->channels = ms5611_channels; 256 indio_dev->num_channels = ARRAY_SIZE(ms5611_channels); 257 indio_dev->modes = INDIO_DIRECT_MODE; 258 259 ret = ms5611_init(indio_dev); 260 if (ret < 0) 261 return ret; 262 263 return devm_iio_device_register(dev, indio_dev); 264 } 265 EXPORT_SYMBOL(ms5611_probe); 266 267 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>"); 268 MODULE_DESCRIPTION("MS5611 core driver"); 269 MODULE_LICENSE("GPL v2"); 270