293 lines
6.9 KiB
C
293 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2016 Marek Vasut <marex@denx.de>
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*
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* Driver for Hope RF HP03 digital temperature and pressure sensor.
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*/
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#define pr_fmt(fmt) "hp03: " fmt
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/i2c.h>
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#include <linux/regmap.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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/*
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* The HP03 sensor occupies two fixed I2C addresses:
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* 0x50 ... read-only EEPROM with calibration data
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* 0x77 ... read-write ADC for pressure and temperature
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*/
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#define HP03_EEPROM_ADDR 0x50
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#define HP03_ADC_ADDR 0x77
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#define HP03_EEPROM_CX_OFFSET 0x10
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#define HP03_EEPROM_AB_OFFSET 0x1e
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#define HP03_EEPROM_CD_OFFSET 0x20
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#define HP03_ADC_WRITE_REG 0xff
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#define HP03_ADC_READ_REG 0xfd
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#define HP03_ADC_READ_PRESSURE 0xf0 /* D1 in datasheet */
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#define HP03_ADC_READ_TEMP 0xe8 /* D2 in datasheet */
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struct hp03_priv {
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struct i2c_client *client;
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struct mutex lock;
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struct gpio_desc *xclr_gpio;
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struct i2c_client *eeprom_client;
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struct regmap *eeprom_regmap;
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s32 pressure; /* kPa */
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s32 temp; /* Deg. C */
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};
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static const struct iio_chan_spec hp03_channels[] = {
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{
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.type = IIO_PRESSURE,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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},
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{
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.type = IIO_TEMP,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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},
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};
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static bool hp03_is_writeable_reg(struct device *dev, unsigned int reg)
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{
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return false;
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}
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static bool hp03_is_volatile_reg(struct device *dev, unsigned int reg)
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{
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return false;
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}
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static const struct regmap_config hp03_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = HP03_EEPROM_CD_OFFSET + 1,
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.cache_type = REGCACHE_RBTREE,
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.writeable_reg = hp03_is_writeable_reg,
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.volatile_reg = hp03_is_volatile_reg,
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};
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static int hp03_get_temp_pressure(struct hp03_priv *priv, const u8 reg)
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{
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int ret;
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ret = i2c_smbus_write_byte_data(priv->client, HP03_ADC_WRITE_REG, reg);
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if (ret < 0)
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return ret;
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msleep(50); /* Wait for conversion to finish */
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return i2c_smbus_read_word_data(priv->client, HP03_ADC_READ_REG);
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}
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static int hp03_update_temp_pressure(struct hp03_priv *priv)
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{
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struct device *dev = &priv->client->dev;
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u8 coefs[18];
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u16 cx_val[7];
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int ab_val, d1_val, d2_val, diff_val, dut, off, sens, x;
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int i, ret;
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/* Sample coefficients from EEPROM */
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ret = regmap_bulk_read(priv->eeprom_regmap, HP03_EEPROM_CX_OFFSET,
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coefs, sizeof(coefs));
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if (ret < 0) {
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dev_err(dev, "Failed to read EEPROM (reg=%02x)\n",
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HP03_EEPROM_CX_OFFSET);
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return ret;
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}
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/* Sample Temperature and Pressure */
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gpiod_set_value_cansleep(priv->xclr_gpio, 1);
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ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_PRESSURE);
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if (ret < 0) {
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dev_err(dev, "Failed to read pressure\n");
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goto err_adc;
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}
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d1_val = ret;
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ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_TEMP);
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if (ret < 0) {
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dev_err(dev, "Failed to read temperature\n");
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goto err_adc;
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}
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d2_val = ret;
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gpiod_set_value_cansleep(priv->xclr_gpio, 0);
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/* The Cx coefficients and Temp/Pressure values are MSB first. */
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for (i = 0; i < 7; i++)
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cx_val[i] = (coefs[2 * i] << 8) | (coefs[(2 * i) + 1] << 0);
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d1_val = ((d1_val >> 8) & 0xff) | ((d1_val & 0xff) << 8);
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d2_val = ((d2_val >> 8) & 0xff) | ((d2_val & 0xff) << 8);
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/* Coefficient voodoo from the HP03 datasheet. */
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if (d2_val >= cx_val[4])
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ab_val = coefs[14]; /* A-value */
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else
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ab_val = coefs[15]; /* B-value */
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diff_val = d2_val - cx_val[4];
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dut = (ab_val * (diff_val >> 7) * (diff_val >> 7)) >> coefs[16];
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dut = diff_val - dut;
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off = (cx_val[1] + (((cx_val[3] - 1024) * dut) >> 14)) * 4;
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sens = cx_val[0] + ((cx_val[2] * dut) >> 10);
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x = ((sens * (d1_val - 7168)) >> 14) - off;
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priv->pressure = ((x * 100) >> 5) + (cx_val[6] * 10);
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priv->temp = 250 + ((dut * cx_val[5]) >> 16) - (dut >> coefs[17]);
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return 0;
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err_adc:
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gpiod_set_value_cansleep(priv->xclr_gpio, 0);
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return ret;
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}
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static int hp03_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct hp03_priv *priv = iio_priv(indio_dev);
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int ret;
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mutex_lock(&priv->lock);
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ret = hp03_update_temp_pressure(priv);
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mutex_unlock(&priv->lock);
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if (ret)
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return ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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switch (chan->type) {
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case IIO_PRESSURE:
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*val = priv->pressure;
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return IIO_VAL_INT;
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case IIO_TEMP:
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*val = priv->temp;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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break;
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case IIO_CHAN_INFO_SCALE:
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switch (chan->type) {
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case IIO_PRESSURE:
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*val = 0;
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*val2 = 1000;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_TEMP:
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*val = 10;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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break;
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default:
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return -EINVAL;
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}
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return -EINVAL;
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}
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static const struct iio_info hp03_info = {
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.read_raw = &hp03_read_raw,
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};
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static int hp03_probe(struct i2c_client *client)
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{
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const struct i2c_device_id *id = i2c_client_get_device_id(client);
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struct device *dev = &client->dev;
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struct iio_dev *indio_dev;
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struct hp03_priv *priv;
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int ret;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
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if (!indio_dev)
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return -ENOMEM;
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priv = iio_priv(indio_dev);
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priv->client = client;
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mutex_init(&priv->lock);
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indio_dev->name = id->name;
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indio_dev->channels = hp03_channels;
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indio_dev->num_channels = ARRAY_SIZE(hp03_channels);
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indio_dev->info = &hp03_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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priv->xclr_gpio = devm_gpiod_get_index(dev, "xclr", 0, GPIOD_OUT_HIGH);
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if (IS_ERR(priv->xclr_gpio)) {
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dev_err(dev, "Failed to claim XCLR GPIO\n");
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ret = PTR_ERR(priv->xclr_gpio);
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return ret;
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}
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/*
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* Allocate another device for the on-sensor EEPROM,
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* which has it's dedicated I2C address and contains
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* the calibration constants for the sensor.
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*/
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priv->eeprom_client = devm_i2c_new_dummy_device(dev, client->adapter,
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HP03_EEPROM_ADDR);
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if (IS_ERR(priv->eeprom_client)) {
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dev_err(dev, "New EEPROM I2C device failed\n");
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return PTR_ERR(priv->eeprom_client);
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}
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priv->eeprom_regmap = devm_regmap_init_i2c(priv->eeprom_client,
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&hp03_regmap_config);
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if (IS_ERR(priv->eeprom_regmap)) {
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dev_err(dev, "Failed to allocate EEPROM regmap\n");
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return PTR_ERR(priv->eeprom_regmap);
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}
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ret = devm_iio_device_register(dev, indio_dev);
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if (ret) {
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dev_err(dev, "Failed to register IIO device\n");
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return ret;
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}
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return 0;
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}
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static const struct i2c_device_id hp03_id[] = {
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{ "hp03", 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, hp03_id);
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static const struct of_device_id hp03_of_match[] = {
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{ .compatible = "hoperf,hp03" },
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{ },
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};
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MODULE_DEVICE_TABLE(of, hp03_of_match);
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static struct i2c_driver hp03_driver = {
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.driver = {
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.name = "hp03",
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.of_match_table = hp03_of_match,
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},
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.probe = hp03_probe,
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.id_table = hp03_id,
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};
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module_i2c_driver(hp03_driver);
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MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
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MODULE_DESCRIPTION("Driver for Hope RF HP03 pressure and temperature sensor");
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MODULE_LICENSE("GPL v2");
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