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SubjectRe: [PATCH 1/9] staging: iio: tsl2583: i2c_smbus_write_byte() / i2c_smbus_read_byte() migration
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On 03/11/16 12:56, Brian Masney wrote:
> 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: Brian Masney <masneyb@onstation.org>
> Cc: Julia Lawall <julia.lawall@lip6.fr>
Forgot to say - applied to the togreg branch of iio.git and pushed
out as testing to see what we've missed!

Jonathan
> ---
> drivers/staging/iio/light/tsl2583.c | 85 +++++++------------------------------
> 1 file changed, 16 insertions(+), 69 deletions(-)
>
> diff --git a/drivers/staging/iio/light/tsl2583.c b/drivers/staging/iio/light/tsl2583.c
> index 49b19f5..a3a9095 100644
> --- a/drivers/staging/iio/light/tsl2583.c
> +++ b/drivers/staging/iio/light/tsl2583.c
> @@ -155,39 +155,6 @@ static void taos_defaults(struct tsl2583_chip *chip)
> }
>
> /*
> - * 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
> * integration cycle are read from the device.
> @@ -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",
>

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