1 /* 2 * Copyright (c) 2016 Marek Vasut <marex@denx.de> 3 * 4 * Driver for Hope RF HP03 digital temperature and pressure sensor. 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 11 #define pr_fmt(fmt) "hp03: " fmt 12 13 #include <linux/module.h> 14 #include <linux/delay.h> 15 #include <linux/gpio/consumer.h> 16 #include <linux/i2c.h> 17 #include <linux/regmap.h> 18 #include <linux/iio/iio.h> 19 #include <linux/iio/sysfs.h> 20 21 /* 22 * The HP03 sensor occupies two fixed I2C addresses: 23 * 0x50 ... read-only EEPROM with calibration data 24 * 0x77 ... read-write ADC for pressure and temperature 25 */ 26 #define HP03_EEPROM_ADDR 0x50 27 #define HP03_ADC_ADDR 0x77 28 29 #define HP03_EEPROM_CX_OFFSET 0x10 30 #define HP03_EEPROM_AB_OFFSET 0x1e 31 #define HP03_EEPROM_CD_OFFSET 0x20 32 33 #define HP03_ADC_WRITE_REG 0xff 34 #define HP03_ADC_READ_REG 0xfd 35 #define HP03_ADC_READ_PRESSURE 0xf0 /* D1 in datasheet */ 36 #define HP03_ADC_READ_TEMP 0xe8 /* D2 in datasheet */ 37 38 struct hp03_priv { 39 struct i2c_client *client; 40 struct mutex lock; 41 struct gpio_desc *xclr_gpio; 42 43 struct i2c_client *eeprom_client; 44 struct regmap *eeprom_regmap; 45 46 s32 pressure; /* kPa */ 47 s32 temp; /* Deg. C */ 48 }; 49 50 static const struct iio_chan_spec hp03_channels[] = { 51 { 52 .type = IIO_PRESSURE, 53 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 54 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 55 }, 56 { 57 .type = IIO_TEMP, 58 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 59 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 60 }, 61 }; 62 63 static bool hp03_is_writeable_reg(struct device *dev, unsigned int reg) 64 { 65 return false; 66 } 67 68 static bool hp03_is_volatile_reg(struct device *dev, unsigned int reg) 69 { 70 return false; 71 } 72 73 static const struct regmap_config hp03_regmap_config = { 74 .reg_bits = 8, 75 .val_bits = 8, 76 77 .max_register = HP03_EEPROM_CD_OFFSET + 1, 78 .cache_type = REGCACHE_RBTREE, 79 80 .writeable_reg = hp03_is_writeable_reg, 81 .volatile_reg = hp03_is_volatile_reg, 82 }; 83 84 static int hp03_get_temp_pressure(struct hp03_priv *priv, const u8 reg) 85 { 86 int ret; 87 88 ret = i2c_smbus_write_byte_data(priv->client, HP03_ADC_WRITE_REG, reg); 89 if (ret < 0) 90 return ret; 91 92 msleep(50); /* Wait for conversion to finish */ 93 94 return i2c_smbus_read_word_data(priv->client, HP03_ADC_READ_REG); 95 } 96 97 static int hp03_update_temp_pressure(struct hp03_priv *priv) 98 { 99 struct device *dev = &priv->client->dev; 100 u8 coefs[18]; 101 u16 cx_val[7]; 102 int ab_val, d1_val, d2_val, diff_val, dut, off, sens, x; 103 int i, ret; 104 105 /* Sample coefficients from EEPROM */ 106 ret = regmap_bulk_read(priv->eeprom_regmap, HP03_EEPROM_CX_OFFSET, 107 coefs, sizeof(coefs)); 108 if (ret < 0) { 109 dev_err(dev, "Failed to read EEPROM (reg=%02x)\n", 110 HP03_EEPROM_CX_OFFSET); 111 return ret; 112 } 113 114 /* Sample Temperature and Pressure */ 115 gpiod_set_value_cansleep(priv->xclr_gpio, 1); 116 117 ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_PRESSURE); 118 if (ret < 0) { 119 dev_err(dev, "Failed to read pressure\n"); 120 goto err_adc; 121 } 122 d1_val = ret; 123 124 ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_TEMP); 125 if (ret < 0) { 126 dev_err(dev, "Failed to read temperature\n"); 127 goto err_adc; 128 } 129 d2_val = ret; 130 131 gpiod_set_value_cansleep(priv->xclr_gpio, 0); 132 133 /* The Cx coefficients and Temp/Pressure values are MSB first. */ 134 for (i = 0; i < 7; i++) 135 cx_val[i] = (coefs[2 * i] << 8) | (coefs[(2 * i) + 1] << 0); 136 d1_val = ((d1_val >> 8) & 0xff) | ((d1_val & 0xff) << 8); 137 d2_val = ((d2_val >> 8) & 0xff) | ((d2_val & 0xff) << 8); 138 139 /* Coefficient voodoo from the HP03 datasheet. */ 140 if (d2_val >= cx_val[4]) 141 ab_val = coefs[14]; /* A-value */ 142 else 143 ab_val = coefs[15]; /* B-value */ 144 145 diff_val = d2_val - cx_val[4]; 146 dut = (ab_val * (diff_val >> 7) * (diff_val >> 7)) >> coefs[16]; 147 dut = diff_val - dut; 148 149 off = (cx_val[1] + (((cx_val[3] - 1024) * dut) >> 14)) * 4; 150 sens = cx_val[0] + ((cx_val[2] * dut) >> 10); 151 x = ((sens * (d1_val - 7168)) >> 14) - off; 152 153 priv->pressure = ((x * 100) >> 5) + (cx_val[6] * 10); 154 priv->temp = 250 + ((dut * cx_val[5]) >> 16) - (dut >> coefs[17]); 155 156 return 0; 157 158 err_adc: 159 gpiod_set_value_cansleep(priv->xclr_gpio, 0); 160 return ret; 161 } 162 163 static int hp03_read_raw(struct iio_dev *indio_dev, 164 struct iio_chan_spec const *chan, 165 int *val, int *val2, long mask) 166 { 167 struct hp03_priv *priv = iio_priv(indio_dev); 168 int ret; 169 170 mutex_lock(&priv->lock); 171 ret = hp03_update_temp_pressure(priv); 172 mutex_unlock(&priv->lock); 173 174 if (ret) 175 return ret; 176 177 switch (mask) { 178 case IIO_CHAN_INFO_RAW: 179 switch (chan->type) { 180 case IIO_PRESSURE: 181 *val = priv->pressure; 182 return IIO_VAL_INT; 183 case IIO_TEMP: 184 *val = priv->temp; 185 return IIO_VAL_INT; 186 default: 187 return -EINVAL; 188 } 189 break; 190 case IIO_CHAN_INFO_SCALE: 191 switch (chan->type) { 192 case IIO_PRESSURE: 193 *val = 0; 194 *val2 = 1000; 195 return IIO_VAL_INT_PLUS_MICRO; 196 case IIO_TEMP: 197 *val = 10; 198 return IIO_VAL_INT; 199 default: 200 return -EINVAL; 201 } 202 break; 203 default: 204 return -EINVAL; 205 } 206 207 return -EINVAL; 208 } 209 210 static const struct iio_info hp03_info = { 211 .driver_module = THIS_MODULE, 212 .read_raw = &hp03_read_raw, 213 }; 214 215 static int hp03_probe(struct i2c_client *client, 216 const struct i2c_device_id *id) 217 { 218 struct device *dev = &client->dev; 219 struct iio_dev *indio_dev; 220 struct hp03_priv *priv; 221 int ret; 222 223 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); 224 if (!indio_dev) 225 return -ENOMEM; 226 227 priv = iio_priv(indio_dev); 228 priv->client = client; 229 mutex_init(&priv->lock); 230 231 indio_dev->dev.parent = dev; 232 indio_dev->name = id->name; 233 indio_dev->channels = hp03_channels; 234 indio_dev->num_channels = ARRAY_SIZE(hp03_channels); 235 indio_dev->info = &hp03_info; 236 indio_dev->modes = INDIO_DIRECT_MODE; 237 238 priv->xclr_gpio = devm_gpiod_get_index(dev, "xclr", 0, GPIOD_OUT_HIGH); 239 if (IS_ERR(priv->xclr_gpio)) { 240 dev_err(dev, "Failed to claim XCLR GPIO\n"); 241 ret = PTR_ERR(priv->xclr_gpio); 242 return ret; 243 } 244 245 /* 246 * Allocate another device for the on-sensor EEPROM, 247 * which has it's dedicated I2C address and contains 248 * the calibration constants for the sensor. 249 */ 250 priv->eeprom_client = i2c_new_dummy(client->adapter, HP03_EEPROM_ADDR); 251 if (!priv->eeprom_client) { 252 dev_err(dev, "New EEPROM I2C device failed\n"); 253 return -ENODEV; 254 } 255 256 priv->eeprom_regmap = regmap_init_i2c(priv->eeprom_client, 257 &hp03_regmap_config); 258 if (IS_ERR(priv->eeprom_regmap)) { 259 dev_err(dev, "Failed to allocate EEPROM regmap\n"); 260 ret = PTR_ERR(priv->eeprom_regmap); 261 goto err_cleanup_eeprom_client; 262 } 263 264 ret = iio_device_register(indio_dev); 265 if (ret) { 266 dev_err(dev, "Failed to register IIO device\n"); 267 goto err_cleanup_eeprom_regmap; 268 } 269 270 i2c_set_clientdata(client, indio_dev); 271 272 return 0; 273 274 err_cleanup_eeprom_regmap: 275 regmap_exit(priv->eeprom_regmap); 276 277 err_cleanup_eeprom_client: 278 i2c_unregister_device(priv->eeprom_client); 279 return ret; 280 } 281 282 static int hp03_remove(struct i2c_client *client) 283 { 284 struct iio_dev *indio_dev = i2c_get_clientdata(client); 285 struct hp03_priv *priv = iio_priv(indio_dev); 286 287 iio_device_unregister(indio_dev); 288 regmap_exit(priv->eeprom_regmap); 289 i2c_unregister_device(priv->eeprom_client); 290 291 return 0; 292 } 293 294 static const struct i2c_device_id hp03_id[] = { 295 { "hp03", 0 }, 296 { }, 297 }; 298 MODULE_DEVICE_TABLE(i2c, hp03_id); 299 300 static struct i2c_driver hp03_driver = { 301 .driver = { 302 .name = "hp03", 303 }, 304 .probe = hp03_probe, 305 .remove = hp03_remove, 306 .id_table = hp03_id, 307 }; 308 module_i2c_driver(hp03_driver); 309 310 MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); 311 MODULE_DESCRIPTION("Driver for Hope RF HP03 pressure and temperature sensor"); 312 MODULE_LICENSE("GPL v2"); 313