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Release 4.7 drivers/iio/pressure/hp03.c

/*
 * 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; }

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static bool hp03_is_volatile_reg(struct device *dev, unsigned int reg) { return false; }

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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); }

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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; }

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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; }

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static const struct iio_info hp03_info = { .driver_module = THIS_MODULE, .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(dev, "Failed to register IIO device\n"); goto err_cleanup_eeprom_regmap; } i2c_set_clientdata(client, indio_dev); return 0; err_cleanup_eeprom_regmap: regmap_exit(priv->eeprom_regmap); err_cleanup_eeprom_client: i2c_unregister_device(priv->eeprom_client); return ret; }

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static int hp03_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); struct hp03_priv *priv = iio_priv(indio_dev); iio_device_unregister(indio_dev); regmap_exit(priv->eeprom_regmap); i2c_unregister_device(priv->eeprom_client); return 0; }

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static const struct i2c_device_id hp03_id[] = { { "hp03", 0 }, { }, }; MODULE_DEVICE_TABLE(i2c, hp03_id); static struct i2c_driver hp03_driver = { .driver = { .name = "hp03", }, .probe = hp03_probe, .remove = hp03_remove, .id_table = hp03_id, }; module_i2c_driver(hp03_driver); MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); MODULE_DESCRIPTION("Driver for Hope RF HP03 pressure and temperature sensor"); MODULE_LICENSE("GPL v2");

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