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/*
* Copyright (c) 2016 Marek Vasut <marex@denx.de>
*
* Driver for Hope RF HP03 digital temperature and pressure sensor.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) "hp03: " fmt
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
/*
* The HP03 sensor occupies two fixed I2C addresses:
* 0x50 ... read-only EEPROM with calibration data
* 0x77 ... read-write ADC for pressure and temperature
*/
#define HP03_EEPROM_ADDR 0x50
#define HP03_ADC_ADDR 0x77
#define HP03_EEPROM_CX_OFFSET 0x10
#define HP03_EEPROM_AB_OFFSET 0x1e
#define HP03_EEPROM_CD_OFFSET 0x20
#define HP03_ADC_WRITE_REG 0xff
#define HP03_ADC_READ_REG 0xfd
#define HP03_ADC_READ_PRESSURE 0xf0 /* D1 in datasheet */
#define HP03_ADC_READ_TEMP 0xe8 /* D2 in datasheet */
struct hp03_priv {
struct i2c_client *client;
struct mutex lock;
struct gpio_desc *xclr_gpio;
struct i2c_client *eeprom_client;
struct regmap *eeprom_regmap;
s32 pressure; /* kPa */
s32 temp; /* Deg. C */
};
static const struct iio_chan_spec hp03_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
},
};
static bool hp03_is_writeable_reg(struct device *dev, unsigned int reg)
{
return false;
}
static bool hp03_is_volatile_reg(struct device *dev, unsigned int reg)
{
return false;
}
static const struct regmap_config hp03_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = HP03_EEPROM_CD_OFFSET + 1,
.cache_type = REGCACHE_RBTREE,
.writeable_reg = hp03_is_writeable_reg,
.volatile_reg = hp03_is_volatile_reg,
};
static int hp03_get_temp_pressure(struct hp03_priv *priv, const u8 reg)
{
int ret;
ret = i2c_smbus_write_byte_data(priv->client, HP03_ADC_WRITE_REG, reg);
if (ret < 0)
return ret;
msleep(50); /* Wait for conversion to finish */
return i2c_smbus_read_word_data(priv->client, HP03_ADC_READ_REG);
}
static int hp03_update_temp_pressure(struct hp03_priv *priv)
{
struct device *dev = &priv->client->dev;
u8 coefs[18];
u16 cx_val[7];
int ab_val, d1_val, d2_val, diff_val, dut, off, sens, x;
int i, ret;
/* Sample coefficients from EEPROM */
ret = regmap_bulk_read(priv->eeprom_regmap, HP03_EEPROM_CX_OFFSET,
coefs, sizeof(coefs));
if (ret < 0) {
dev_err(dev, "Failed to read EEPROM (reg=%02x)\n",
HP03_EEPROM_CX_OFFSET);
return ret;
}
/* Sample Temperature and Pressure */
gpiod_set_value_cansleep(priv->xclr_gpio, 1);
ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_PRESSURE);
if (ret < 0) {
dev_err(dev, "Failed to read pressure\n");
goto err_adc;
}
d1_val = ret;
ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_TEMP);
if (ret < 0) {
dev_err(dev, "Failed to read temperature\n");
goto err_adc;
}
d2_val = ret;
gpiod_set_value_cansleep(priv->xclr_gpio, 0);
/* The Cx coefficients and Temp/Pressure values are MSB first. */
for (i = 0; i < 7; i++)
cx_val[i] = (coefs[2 * i] << 8) | (coefs[(2 * i) + 1] << 0);
d1_val = ((d1_val >> 8) & 0xff) | ((d1_val & 0xff) << 8);
d2_val = ((d2_val >> 8) & 0xff) | ((d2_val & 0xff) << 8);
/* Coefficient voodoo from the HP03 datasheet. */
if (d2_val >= cx_val[4])
ab_val = coefs[14]; /* A-value */
else
ab_val = coefs[15]; /* B-value */
diff_val = d2_val - cx_val[4];
dut = (ab_val * (diff_val >> 7) * (diff_val >> 7)) >> coefs[16];
dut = diff_val - dut;
off = (cx_val[1] + (((cx_val[3] - 1024) * dut) >> 14)) * 4;
sens = cx_val[0] + ((cx_val[2] * dut) >> 10);
x = ((sens * (d1_val - 7168)) >> 14) - off;
priv->pressure = ((x * 100) >> 5) + (cx_val[6] * 10);
priv->temp = 250 + ((dut * cx_val[5]) >> 16) - (dut >> coefs[17]);
return 0;
err_adc:
gpiod_set_value_cansleep(priv->xclr_gpio, 0);
return ret;
}
static int hp03_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct hp03_priv *priv = iio_priv(indio_dev);
int ret;
mutex_lock(&priv->lock);
ret = hp03_update_temp_pressure(priv);
mutex_unlock(&priv->lock);
if (ret)
return ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
switch (chan->type) {
case IIO_PRESSURE:
*val = priv->pressure;
return IIO_VAL_INT;
case IIO_TEMP:
*val = priv->temp;
return IIO_VAL_INT;
default:
return -EINVAL;
}
break;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_PRESSURE:
*val = 0;
*val2 = 1000;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_TEMP:
*val = 10;
return IIO_VAL_INT;
default:
return -EINVAL;
}
break;
default:
return -EINVAL;
}
return -EINVAL;
}
static const struct iio_info hp03_info = {
.read_raw = &hp03_read_raw,
};
static int hp03_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct iio_dev *indio_dev;
struct hp03_priv *priv;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
if (!indio_dev)
return -ENOMEM;
priv = iio_priv(indio_dev);
priv->client = client;
mutex_init(&priv->lock);
indio_dev->dev.parent = dev;
indio_dev->name = id->name;
indio_dev->channels = hp03_channels;
indio_dev->num_channels = ARRAY_SIZE(hp03_channels);
indio_dev->info = &hp03_info;
indio_dev->modes = INDIO_DIRECT_MODE;
priv->xclr_gpio = devm_gpiod_get_index(dev, "xclr", 0, GPIOD_OUT_HIGH);
if (IS_ERR(priv->xclr_gpio)) {
dev_err(dev, "Failed to claim XCLR GPIO\n");
ret = PTR_ERR(priv->xclr_gpio);
return ret;
}
/*
* Allocate another device for the on-sensor EEPROM,
* which has it's dedicated I2C address and contains
* the calibration constants for the sensor.
*/
priv->eeprom_client = i2c_new_dummy(client->adapter, HP03_EEPROM_ADDR);
if (!priv->eeprom_client) {
dev_err(dev, "New EEPROM I2C device failed\n");
return -ENODEV;
}
priv->eeprom_regmap = regmap_init_i2c(priv->eeprom_client,
&hp03_regmap_config);
if (IS_ERR(priv->eeprom_regmap)) {
dev_err(dev, "Failed to allocate EEPROM regmap\n");
ret = PTR_ERR(priv->eeprom_regmap);
goto err_cleanup_eeprom_client;
}
ret = iio_device_register(indio_dev);
if (ret) {
dev_err
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