Re: [PATCH v2 1/3] light sensor: Add SMBUS support to the tsl2563driver.

[Jonathan Cameron]

On 06/24/11 00:12, Bryan Freed wrote:
> This is so we can support it on x86 SMBUS adapters.
> 
> Since i2c adapters which do not provide an smbus_xfer interface fall
> back to using their I2C master_xfer interface, all the i2c_master_send()
> calls in this driver are changed to i2c_smbus_*() calls.
> This will fail on an i2c adapter that implements a proper subset of
> (SMBUS_BYTE | SMBUS_BYTE_DATA | SMBUS_WORD_DATA), but I do not see that
> in any of our adapters today.
Hi Brian,

Principal looking good.

You've been careful to minimize apparent changes, but as a result
we now have some really short and largely pointless wrappers.  Please
squash them into the calling locations.  That way we get a cleaner
result (which makes me happy ;)  Given all call sites are changing
anyway, such a patch will only be marginally more invasive.

Jonathan
> 
> Signed-off-by: Bryan Freed <bfreed@xxxxxxxxxxxx>
> ---
>  drivers/staging/iio/light/tsl2563.c |   62 +++++++++++++++++------------------
>  1 files changed, 30 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/staging/iio/light/tsl2563.c b/drivers/staging/iio/light/tsl2563.c
> index 9cffa2e..14fc337 100644
> --- a/drivers/staging/iio/light/tsl2563.c
> +++ b/drivers/staging/iio/light/tsl2563.c
> @@ -139,26 +139,33 @@ struct tsl2563_chip {
>  
>  static int tsl2563_write(struct i2c_client *client, u8 reg, u8 value)
>  {
> -	int ret;
> -	u8 buf[2];
> -
> -	buf[0] = TSL2563_CMD | reg;
> -	buf[1] = value;
> +	return i2c_smbus_write_byte_data(client, TSL2563_CMD | reg, value);
> +}
Please just get rid of this fucntion enirely. It can be trivially made inline
for all users.
>  
> -	ret = i2c_master_send(client, buf, sizeof(buf));
> -	return (ret == sizeof(buf)) ? 0 : ret;
> +static int tsl2563_write_quick(struct i2c_client *client, u8 reg)
> +{
> +	return i2c_smbus_write_byte(client, TSL2563_CMD | reg);
>  }
Same here. This sort of short inline just makes the code harder to read.

>  
> -static int tsl2563_read(struct i2c_client *client, u8 reg, void *buf, int len)
> +static int tsl2563_read8(struct i2c_client *client, u8 reg, u8 *buf)
>  {
>  	int ret;
> -	u8 cmd = TSL2563_CMD | reg;
>  
> -	ret = i2c_master_send(client, &cmd, sizeof(cmd));
> -	if (ret != sizeof(cmd))
> +	ret = i2c_smbus_read_byte_data(client, TSL2563_CMD | reg);
> +	if (ret < 0)
>  		return ret;
> +	*buf = ret & 0xff;
mask isn't needed as you are copying a guaranteeded 8 bit unsigned value
from an int to a u8.  Hence, this function should go away and the
i2c_smbus_read_byte_data call used directly for all call sites.
> +	return 0;
> +}
> +
> +static int tsl2563_read16(struct i2c_client *client, u8 reg, u16 *buf)
> +{
> +	int ret;
>  
> -	return i2c_master_recv(client, buf, len);
> +	ret = i2c_smbus_read_word_data(client, TSL2563_CMD | reg);
> +	if (ret < 0)
> +		return ret;
> +	*buf = ret & 0xffff;
Same for this one as the read8. Better to handle the data storage in
the callers.
>  }
>  
>  static int tsl2563_set_power(struct tsl2563_chip *chip, int on)
> @@ -180,8 +187,8 @@ static int tsl2563_get_power(struct tsl2563_chip *chip)
>  	int ret;
>  	u8 val;
>  
> -	ret = tsl2563_read(client, TSL2563_REG_CTRL, &val, sizeof(val));
> -	if (ret != sizeof(val))
> +	ret = tsl2563_read8(client, TSL2563_REG_CTRL, &val);
> +	if (ret)
>  		return ret;
>  
>  	return (val & TSL2563_CTRL_POWER_MASK) == TSL2563_CMD_POWER_ON;
> @@ -242,8 +249,8 @@ static int tsl2563_read_id(struct tsl2563_chip *chip, u8 *id)
>  	struct i2c_client *client = chip->client;
>  	int ret;
>  
> -	ret = tsl2563_read(client, TSL2563_REG_ID, id, sizeof(*id));
> -	if (ret != sizeof(*id))
> +	ret = tsl2563_read8(client, TSL2563_REG_ID, id);
> +	if (ret)
>  		return ret;
>  
>  	return 0;
> @@ -327,7 +334,6 @@ static int tsl2563_adjust_gainlevel(struct tsl2563_chip *chip, u16 adc)
>  static int tsl2563_get_adc(struct tsl2563_chip *chip)
>  {
>  	struct i2c_client *client = chip->client;
> -	u8 buf0[2], buf1[2];
>  	u16 adc0, adc1;
>  	int retry = 1;
>  	int ret = 0;
> @@ -350,20 +356,14 @@ static int tsl2563_get_adc(struct tsl2563_chip *chip)
>  	}
>  
>  	while (retry) {
> -		ret = tsl2563_read(client,
> -				   TSL2563_REG_DATA0LOW,
> -				   buf0, sizeof(buf0));
> -		if (ret != sizeof(buf0))
> +		ret = tsl2563_read16(client, TSL2563_REG_DATA0LOW, &adc0);
> +		if (ret)
>  			goto out;
>  
> -		ret = tsl2563_read(client, TSL2563_REG_DATA1LOW,
> -				   buf1, sizeof(buf1));
> -		if (ret != sizeof(buf1))
> +		ret = tsl2563_read16(client, TSL2563_REG_DATA1LOW, &adc1);
> +		if (ret)
>  			goto out;
>  
> -		adc0 = (buf0[1] << 8) + buf0[0];
> -		adc1 = (buf1[1] << 8) + buf1[0];
> -
>  		retry = tsl2563_adjust_gainlevel(chip, adc0);
>  	}
>  
> @@ -612,7 +612,6 @@ static irqreturn_t tsl2563_event_handler(int irq, void *private)
>  {
>  	struct iio_dev *dev_info = private;
>  	struct tsl2563_chip *chip = iio_priv(dev_info);
> -	u8 cmd = TSL2563_CMD | TSL2563_CLEARINT;
>  
>  	iio_push_event(dev_info, 0,
>  		       IIO_UNMOD_EVENT_CODE(IIO_EV_CLASS_LIGHT,
> @@ -622,7 +621,7 @@ static irqreturn_t tsl2563_event_handler(int irq, void *private)
>  		       iio_get_time_ns());
>  
>  	/* clear the interrupt and push the event */
> -	i2c_master_send(chip->client, &cmd, sizeof(cmd));
> +	tsl2563_write_quick(chip->client, TSL2563_CLEARINT);
>  	return IRQ_HANDLED;
>  }
>  
> @@ -672,10 +671,9 @@ static int tsl2563_read_interrupt_config(struct iio_dev *indio_dev,
>  	int ret;
>  
>  	mutex_lock(&chip->lock);
> -	ret = tsl2563_read(chip->client, TSL2563_REG_INT,
> -			   &rxbuf, sizeof(rxbuf));
> +	ret = tsl2563_read8(chip->client, TSL2563_REG_INT, &rxbuf);
>  	mutex_unlock(&chip->lock);
> -	if (ret < 0)
> +	if (ret)
>  		goto error_ret;
>  	ret = !!(rxbuf & 0x30);
>  error_ret:

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