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Commit 6ba5dee9 authored by Brian Masney's avatar Brian Masney Committed by Jonathan Cameron
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staging: iio: tsl2583: i2c_smbus_write_byte() / i2c_smbus_read_byte() migration 



There were several places where the driver would first call
i2c_smbus_write_byte() to select the register on the device, and then
call i2c_smbus_read_byte() to get the contents of that register. The
code would look roughly like:

/* Select register */
i2c_smbus_write_byte(client, REGISTER);

/* Read the the last register that was written to */
int data = i2c_smbus_read_byte(client);

Rewrite this to use i2c_smbus_read_byte_data() to combine the two
calls into one:

int data = i2c_smbus_read_byte_data(chip->client, REGISTER);

Verified that the driver still functions correctly using a TSL2581
hooked up to a Raspberry Pi 2.

This fixes the following warnings that were found by the
kbuild test robot that were introduced by commit 8ba355cce3c6 ("staging:
iio: tsl2583: check for error code from i2c_smbus_read_byte()").

drivers/staging/iio/light/tsl2583.c:365:5-12: WARNING: Unsigned
expression compared with zero: reg_val < 0

drivers/staging/iio/light/tsl2583.c:388:5-12: WARNING: Unsigned
expression compared with zero: reg_val < 0

This also removes the need for the taos_i2c_read() function since all
callers were only calling the function with a length of 1.

Signed-off-by: default avatarBrian Masney <masneyb@onstation.org>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 25acb398

drivers/staging/iio/light/tsl2583.c

+16 −69
Original line number Diff line number Diff line
@@ -154,39 +154,6 @@ static void taos_defaults(struct tsl2583_chip *chip) 
	/* Known external ALS reading used for calibration */

}



/*

 * Read a number of bytes starting at register (reg) location.

 * Return 0, or i2c_smbus_write_byte ERROR code.

 */

static int

taos_i2c_read(struct i2c_client *client, u8 reg, u8 *val, unsigned int len)

{

	int i, ret;



	for (i = 0; i < len; i++) {

		/* select register to write */

		ret = i2c_smbus_write_byte(client, (TSL258X_CMD_REG | reg));

		if (ret < 0) {

			dev_err(&client->dev,

				"taos_i2c_read failed to write register %x\n",

				reg);

			return ret;

		}

		/* read the data */

		ret = i2c_smbus_read_byte(client);

		if (ret < 0) {

			dev_err(&client->dev,

				"%s failed to read byte after writing to register %x\n",

				__func__, reg);

			return ret;

		}

		*val = ret;

		val++;

		reg++;

	}

	return 0;

}



/*

 * Reads and calculates current lux value.

 * The raw ch0 and ch1 values of the ambient light sensed in the last
@@ -220,13 +187,14 @@ static int taos_get_lux(struct iio_dev *indio_dev) 
		goto done;

	}



	ret = taos_i2c_read(chip->client, (TSL258X_CMD_REG), &buf[0], 1);

	ret = i2c_smbus_read_byte_data(chip->client, TSL258X_CMD_REG);

	if (ret < 0) {

		dev_err(&chip->client->dev, "taos_get_lux failed to read CMD_REG\n");

		goto done;

	}



	/* is data new & valid */

	if (!(buf[0] & TSL258X_STA_ADC_INTR)) {

	if (!(ret & TSL258X_STA_ADC_INTR)) {

		dev_err(&chip->client->dev, "taos_get_lux data not valid\n");

		ret = chip->als_cur_info.lux; /* return LAST VALUE */

		goto done;
@@ -235,13 +203,14 @@ static int taos_get_lux(struct iio_dev *indio_dev) 
	for (i = 0; i < 4; i++) {

		int reg = TSL258X_CMD_REG | (TSL258X_ALS_CHAN0LO + i);



		ret = taos_i2c_read(chip->client, reg, &buf[i], 1);

		ret = i2c_smbus_read_byte_data(chip->client, reg);

		if (ret < 0) {

			dev_err(&chip->client->dev,

				"taos_get_lux failed to read register %x\n",

				reg);

			goto done;

		}

		buf[i] = ret;

	}



	/*
@@ -343,52 +312,36 @@ static int taos_get_lux(struct iio_dev *indio_dev) 
static int taos_als_calibrate(struct iio_dev *indio_dev)

{

	struct tsl2583_chip *chip = iio_priv(indio_dev);

	u8 reg_val;

	unsigned int gain_trim_val;

	int ret;

	int lux_val;



	ret = i2c_smbus_write_byte(chip->client,

				   (TSL258X_CMD_REG | TSL258X_CNTRL));

	ret = i2c_smbus_read_byte_data(chip->client,

				       TSL258X_CMD_REG | TSL258X_CNTRL);

	if (ret < 0) {

		dev_err(&chip->client->dev,

			"taos_als_calibrate failed to reach the CNTRL register, ret=%d\n",

			ret);

		return ret;

	}



	reg_val = i2c_smbus_read_byte(chip->client);

	if (reg_val < 0) {

		dev_err(&chip->client->dev,

			"%s failed to read after writing to the CNTRL register\n",

			"%s failed to read from the CNTRL register\n",

			__func__);

		return ret;

	}



	if ((reg_val & (TSL258X_CNTL_ADC_ENBL | TSL258X_CNTL_PWR_ON))

	if ((ret & (TSL258X_CNTL_ADC_ENBL | TSL258X_CNTL_PWR_ON))

			!= (TSL258X_CNTL_ADC_ENBL | TSL258X_CNTL_PWR_ON)) {

		dev_err(&chip->client->dev,

			"taos_als_calibrate failed: device not powered on with ADC enabled\n");

		return -EINVAL;

	}



	ret = i2c_smbus_write_byte(chip->client,

				   (TSL258X_CMD_REG | TSL258X_CNTRL));

	ret = i2c_smbus_read_byte_data(chip->client,

				       TSL258X_CMD_REG | TSL258X_CNTRL);

	if (ret < 0) {

		dev_err(&chip->client->dev,

			"taos_als_calibrate failed to reach the STATUS register, ret=%d\n",

			ret);

		return ret;

	}

	reg_val = i2c_smbus_read_byte(chip->client);

	if (reg_val < 0) {

		dev_err(&chip->client->dev,

			"%s failed to read after writing to the STATUS register\n",

			"%s failed to read from the CNTRL register\n",

			__func__);

		return ret;

	}



	if ((reg_val & TSL258X_STA_ADC_VALID) != TSL258X_STA_ADC_VALID) {

	if ((ret & TSL258X_STA_ADC_VALID) != TSL258X_STA_ADC_VALID) {

		dev_err(&chip->client->dev,

			"taos_als_calibrate failed: STATUS - ADC not valid.\n");

		return -ENODATA;
@@ -847,15 +800,9 @@ static int taos_probe(struct i2c_client *clientp, 
	memcpy(chip->taos_config, taos_config, sizeof(chip->taos_config));



	for (i = 0; i < TSL258X_MAX_DEVICE_REGS; i++) {

		ret = i2c_smbus_write_byte(clientp,

				(TSL258X_CMD_REG | (TSL258X_CNTRL + i)));

		if (ret < 0) {

			dev_err(&clientp->dev,

				"i2c_smbus_write_byte to cmd reg failed in taos_probe(), err = %d\n",

				ret);

			return ret;

		}

		ret = i2c_smbus_read_byte(clientp);

		ret = i2c_smbus_read_byte_data(clientp,

					       (TSL258X_CMD_REG |

						(TSL258X_CNTRL + i)));

		if (ret < 0) {

			dev_err(&clientp->dev,

				"i2c_smbus_read_byte from reg failed in taos_probe(), err = %d\n",