427 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			427 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * hp206c.c - HOPERF HP206C precision barometer and altimeter sensor
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|  *
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|  * Copyright (c) 2016, Intel Corporation.
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|  *
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|  * This file is subject to the terms and conditions of version 2 of
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|  * the GNU General Public License.  See the file COPYING in the main
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|  * directory of this archive for more details.
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|  *
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|  * (7-bit I2C slave address 0x76)
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|  *
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|  * Datasheet:
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|  *  http://www.hoperf.com/upload/sensor/HP206C_DataSheet_EN_V2.0.pdf
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|  */
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| 
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| #include <linux/module.h>
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| #include <linux/i2c.h>
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| #include <linux/iio/iio.h>
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| #include <linux/iio/sysfs.h>
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| #include <linux/delay.h>
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| #include <linux/util_macros.h>
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| #include <linux/acpi.h>
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| 
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| /* I2C commands: */
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| #define HP206C_CMD_SOFT_RST	0x06
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| 
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| #define HP206C_CMD_ADC_CVT	0x40
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| 
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| #define HP206C_CMD_ADC_CVT_OSR_4096	0x00
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| #define HP206C_CMD_ADC_CVT_OSR_2048	0x04
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| #define HP206C_CMD_ADC_CVT_OSR_1024	0x08
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| #define HP206C_CMD_ADC_CVT_OSR_512	0x0c
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| #define HP206C_CMD_ADC_CVT_OSR_256	0x10
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| #define HP206C_CMD_ADC_CVT_OSR_128	0x14
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| 
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| #define HP206C_CMD_ADC_CVT_CHNL_PT	0x00
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| #define HP206C_CMD_ADC_CVT_CHNL_T	0x02
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| 
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| #define HP206C_CMD_READ_P	0x30
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| #define HP206C_CMD_READ_T	0x32
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| 
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| #define HP206C_CMD_READ_REG	0x80
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| #define HP206C_CMD_WRITE_REG	0xc0
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| 
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| #define HP206C_REG_INT_EN	0x0b
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| #define HP206C_REG_INT_CFG	0x0c
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| 
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| #define HP206C_REG_INT_SRC	0x0d
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| #define HP206C_FLAG_DEV_RDY	0x40
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| 
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| #define HP206C_REG_PARA		0x0f
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| #define HP206C_FLAG_CMPS_EN	0x80
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| 
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| /* Maximum spin for DEV_RDY */
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| #define HP206C_MAX_DEV_RDY_WAIT_COUNT 20
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| #define HP206C_DEV_RDY_WAIT_US    20000
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| 
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| struct hp206c_data {
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| 	struct mutex mutex;
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| 	struct i2c_client *client;
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| 	int temp_osr_index;
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| 	int pres_osr_index;
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| };
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| 
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| struct hp206c_osr_setting {
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| 	u8 osr_mask;
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| 	unsigned int temp_conv_time_us;
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| 	unsigned int pres_conv_time_us;
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| };
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| 
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| /* Data from Table 5 in datasheet. */
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| static const struct hp206c_osr_setting hp206c_osr_settings[] = {
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| 	{ HP206C_CMD_ADC_CVT_OSR_4096,	65600,	131100	},
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| 	{ HP206C_CMD_ADC_CVT_OSR_2048,	32800,	65600	},
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| 	{ HP206C_CMD_ADC_CVT_OSR_1024,	16400,	32800	},
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| 	{ HP206C_CMD_ADC_CVT_OSR_512,	8200,	16400	},
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| 	{ HP206C_CMD_ADC_CVT_OSR_256,	4100,	8200	},
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| 	{ HP206C_CMD_ADC_CVT_OSR_128,	2100,	4100	},
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| };
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| static const int hp206c_osr_rates[] = { 4096, 2048, 1024, 512, 256, 128 };
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| static const char hp206c_osr_rates_str[] = "4096 2048 1024 512 256 128";
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| 
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| static inline int hp206c_read_reg(struct i2c_client *client, u8 reg)
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| {
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| 	return i2c_smbus_read_byte_data(client, HP206C_CMD_READ_REG | reg);
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| }
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| 
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| static inline int hp206c_write_reg(struct i2c_client *client, u8 reg, u8 val)
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| {
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| 	return i2c_smbus_write_byte_data(client,
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| 			HP206C_CMD_WRITE_REG | reg, val);
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| }
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| 
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| static int hp206c_read_20bit(struct i2c_client *client, u8 cmd)
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| {
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| 	int ret;
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| 	u8 values[3];
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| 
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| 	ret = i2c_smbus_read_i2c_block_data(client, cmd, 3, values);
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| 	if (ret < 0)
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| 		return ret;
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| 	if (ret != 3)
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| 		return -EIO;
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| 	return ((values[0] & 0xF) << 16) | (values[1] << 8) | (values[2]);
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| }
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| 
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| /* Spin for max 160ms until DEV_RDY is 1, or return error. */
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| static int hp206c_wait_dev_rdy(struct iio_dev *indio_dev)
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| {
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| 	int ret;
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| 	int count = 0;
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| 	struct hp206c_data *data = iio_priv(indio_dev);
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| 	struct i2c_client *client = data->client;
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| 
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| 	while (++count <= HP206C_MAX_DEV_RDY_WAIT_COUNT) {
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| 		ret = hp206c_read_reg(client, HP206C_REG_INT_SRC);
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| 		if (ret < 0) {
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| 			dev_err(&indio_dev->dev, "Failed READ_REG INT_SRC: %d\n", ret);
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| 			return ret;
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| 		}
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| 		if (ret & HP206C_FLAG_DEV_RDY)
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| 			return 0;
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| 		usleep_range(HP206C_DEV_RDY_WAIT_US, HP206C_DEV_RDY_WAIT_US * 3 / 2);
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| 	}
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| 	return -ETIMEDOUT;
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| }
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| 
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| static int hp206c_set_compensation(struct i2c_client *client, bool enabled)
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| {
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| 	int val;
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| 
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| 	val = hp206c_read_reg(client, HP206C_REG_PARA);
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| 	if (val < 0)
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| 		return val;
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| 	if (enabled)
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| 		val |= HP206C_FLAG_CMPS_EN;
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| 	else
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| 		val &= ~HP206C_FLAG_CMPS_EN;
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| 
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| 	return hp206c_write_reg(client, HP206C_REG_PARA, val);
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| }
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| 
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| /* Do a soft reset */
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| static int hp206c_soft_reset(struct iio_dev *indio_dev)
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| {
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| 	int ret;
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| 	struct hp206c_data *data = iio_priv(indio_dev);
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| 	struct i2c_client *client = data->client;
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| 
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| 	ret = i2c_smbus_write_byte(client, HP206C_CMD_SOFT_RST);
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| 	if (ret) {
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| 		dev_err(&client->dev, "Failed to reset device: %d\n", ret);
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| 		return ret;
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| 	}
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| 
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| 	usleep_range(400, 600);
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| 
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| 	ret = hp206c_wait_dev_rdy(indio_dev);
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| 	if (ret) {
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| 		dev_err(&client->dev, "Device not ready after soft reset: %d\n", ret);
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| 		return ret;
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| 	}
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| 
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| 	ret = hp206c_set_compensation(client, true);
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| 	if (ret)
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| 		dev_err(&client->dev, "Failed to enable compensation: %d\n", ret);
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| 	return ret;
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| }
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| 
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| static int hp206c_conv_and_read(struct iio_dev *indio_dev,
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| 				u8 conv_cmd, u8 read_cmd,
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| 				unsigned int sleep_us)
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| {
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| 	int ret;
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| 	struct hp206c_data *data = iio_priv(indio_dev);
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| 	struct i2c_client *client = data->client;
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| 
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| 	ret = hp206c_wait_dev_rdy(indio_dev);
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| 	if (ret < 0) {
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| 		dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
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| 		return ret;
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| 	}
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| 
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| 	ret = i2c_smbus_write_byte(client, conv_cmd);
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| 	if (ret < 0) {
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| 		dev_err(&indio_dev->dev, "Failed convert: %d\n", ret);
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| 		return ret;
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| 	}
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| 
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| 	usleep_range(sleep_us, sleep_us * 3 / 2);
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| 
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| 	ret = hp206c_wait_dev_rdy(indio_dev);
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| 	if (ret < 0) {
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| 		dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
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| 		return ret;
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| 	}
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| 
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| 	ret = hp206c_read_20bit(client, read_cmd);
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| 	if (ret < 0)
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| 		dev_err(&indio_dev->dev, "Failed read: %d\n", ret);
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| 
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| 	return ret;
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| }
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| 
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| static int hp206c_read_raw(struct iio_dev *indio_dev,
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| 			   struct iio_chan_spec const *chan, int *val,
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| 			   int *val2, long mask)
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| {
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| 	int ret;
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| 	struct hp206c_data *data = iio_priv(indio_dev);
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| 	const struct hp206c_osr_setting *osr_setting;
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| 	u8 conv_cmd;
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| 
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| 	mutex_lock(&data->mutex);
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| 
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| 	switch (mask) {
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| 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
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| 		switch (chan->type) {
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| 		case IIO_TEMP:
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| 			*val = hp206c_osr_rates[data->temp_osr_index];
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| 			ret = IIO_VAL_INT;
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| 			break;
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| 
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| 		case IIO_PRESSURE:
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| 			*val = hp206c_osr_rates[data->pres_osr_index];
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| 			ret = IIO_VAL_INT;
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| 			break;
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| 		default:
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| 			ret = -EINVAL;
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| 		}
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| 		break;
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| 
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| 	case IIO_CHAN_INFO_RAW:
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| 		switch (chan->type) {
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| 		case IIO_TEMP:
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| 			osr_setting = &hp206c_osr_settings[data->temp_osr_index];
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| 			conv_cmd = HP206C_CMD_ADC_CVT |
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| 					osr_setting->osr_mask |
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| 					HP206C_CMD_ADC_CVT_CHNL_T;
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| 			ret = hp206c_conv_and_read(indio_dev,
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| 					conv_cmd,
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| 					HP206C_CMD_READ_T,
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| 					osr_setting->temp_conv_time_us);
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| 			if (ret >= 0) {
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| 				/* 20 significant bits are provided.
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| 				 * Extend sign over the rest.
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| 				 */
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| 				*val = sign_extend32(ret, 19);
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| 				ret = IIO_VAL_INT;
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| 			}
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| 			break;
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| 
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| 		case IIO_PRESSURE:
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| 			osr_setting = &hp206c_osr_settings[data->pres_osr_index];
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| 			conv_cmd = HP206C_CMD_ADC_CVT |
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| 					osr_setting->osr_mask |
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| 					HP206C_CMD_ADC_CVT_CHNL_PT;
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| 			ret = hp206c_conv_and_read(indio_dev,
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| 					conv_cmd,
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| 					HP206C_CMD_READ_P,
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| 					osr_setting->pres_conv_time_us);
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| 			if (ret >= 0) {
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| 				*val = ret;
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| 				ret = IIO_VAL_INT;
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| 			}
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| 			break;
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| 		default:
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| 			ret = -EINVAL;
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| 		}
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| 		break;
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| 
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| 	case IIO_CHAN_INFO_SCALE:
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| 		switch (chan->type) {
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| 		case IIO_TEMP:
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| 			*val = 0;
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| 			*val2 = 10000;
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| 			ret = IIO_VAL_INT_PLUS_MICRO;
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| 			break;
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| 
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| 		case IIO_PRESSURE:
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| 			*val = 0;
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| 			*val2 = 1000;
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| 			ret = IIO_VAL_INT_PLUS_MICRO;
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| 			break;
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| 		default:
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| 			ret = -EINVAL;
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| 		}
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| 		break;
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| 
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| 	default:
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| 		ret = -EINVAL;
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| 	}
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| 
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| 	mutex_unlock(&data->mutex);
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| 	return ret;
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| }
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| 
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| static int hp206c_write_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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| 	int ret = 0;
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| 	struct hp206c_data *data = iio_priv(indio_dev);
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| 
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| 	if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
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| 		return -EINVAL;
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| 	mutex_lock(&data->mutex);
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| 	switch (chan->type) {
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| 	case IIO_TEMP:
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| 		data->temp_osr_index = find_closest_descending(val,
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| 			hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
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| 		break;
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| 	case IIO_PRESSURE:
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| 		data->pres_osr_index = find_closest_descending(val,
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| 			hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
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| 		break;
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| 	default:
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| 		ret = -EINVAL;
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| 	}
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| 	mutex_unlock(&data->mutex);
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| 	return ret;
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| }
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| 
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| static const struct iio_chan_spec hp206c_channels[] = {
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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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| 				      BIT(IIO_CHAN_INFO_SCALE) |
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| 				      BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
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| 	},
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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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| 				      BIT(IIO_CHAN_INFO_SCALE) |
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| 				      BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
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| 	}
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| };
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| 
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| static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(hp206c_osr_rates_str);
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| 
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| static struct attribute *hp206c_attributes[] = {
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| 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
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| 	NULL,
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| };
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| 
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| static const struct attribute_group hp206c_attribute_group = {
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| 	.attrs = hp206c_attributes,
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| };
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| 
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| static const struct iio_info hp206c_info = {
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| 	.attrs = &hp206c_attribute_group,
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| 	.read_raw = hp206c_read_raw,
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| 	.write_raw = hp206c_write_raw,
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| };
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| 
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| static int hp206c_probe(struct i2c_client *client,
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| 			const struct i2c_device_id *id)
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| {
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| 	struct iio_dev *indio_dev;
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| 	struct hp206c_data *data;
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| 	int ret;
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| 
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| 	if (!i2c_check_functionality(client->adapter,
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| 				     I2C_FUNC_SMBUS_BYTE |
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| 				     I2C_FUNC_SMBUS_BYTE_DATA |
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| 				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
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| 		dev_err(&client->dev, "Adapter does not support "
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| 				"all required i2c functionality\n");
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| 		return -ENODEV;
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| 	}
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| 
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| 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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| 	if (!indio_dev)
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| 		return -ENOMEM;
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| 
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| 	data = iio_priv(indio_dev);
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| 	data->client = client;
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| 	mutex_init(&data->mutex);
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| 
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| 	indio_dev->info = &hp206c_info;
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| 	indio_dev->name = id->name;
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| 	indio_dev->dev.parent = &client->dev;
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| 	indio_dev->modes = INDIO_DIRECT_MODE;
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| 	indio_dev->channels = hp206c_channels;
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| 	indio_dev->num_channels = ARRAY_SIZE(hp206c_channels);
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| 
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| 	i2c_set_clientdata(client, indio_dev);
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| 
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| 	/* Do a soft reset on probe */
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| 	ret = hp206c_soft_reset(indio_dev);
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| 	if (ret) {
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| 		dev_err(&client->dev, "Failed to reset on startup: %d\n", ret);
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| 		return -ENODEV;
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| 	}
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| 
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| 	return devm_iio_device_register(&client->dev, indio_dev);
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| }
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| 
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| static const struct i2c_device_id hp206c_id[] = {
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| 	{"hp206c"},
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| 	{}
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| };
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| MODULE_DEVICE_TABLE(i2c, hp206c_id);
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| 
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| #ifdef CONFIG_ACPI
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| static const struct acpi_device_id hp206c_acpi_match[] = {
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| 	{"HOP206C", 0},
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| 	{ },
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| };
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| MODULE_DEVICE_TABLE(acpi, hp206c_acpi_match);
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| #endif
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| 
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| static struct i2c_driver hp206c_driver = {
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| 	.probe = hp206c_probe,
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| 	.id_table = hp206c_id,
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| 	.driver = {
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| 		.name = "hp206c",
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| 		.acpi_match_table = ACPI_PTR(hp206c_acpi_match),
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| 	},
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| };
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| 
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| module_i2c_driver(hp206c_driver);
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| 
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| MODULE_DESCRIPTION("HOPERF HP206C precision barometer and altimeter sensor");
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| MODULE_AUTHOR("Leonard Crestez <leonard.crestez@intel.com>");
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| MODULE_LICENSE("GPL v2");
 | 
