Re: [RFC 8/8] staging:iio:dac:ad5791: Convert to extended channel attributes

[Jonathan Cameron <jic23@kernel.org>]

On 05/11/2012 04:53 PM, Lars-Peter Clausen wrote:
> Use extended channel attributes instead of raw sysfs files for the additional
> channel attributes. This allows us to remove some boilerplate code.

A nice patch set.  I do wonder if we ultimately need to find common
ground for these power down commands with other subsystems.  I have a
vague feeling that the pinmux stuff will overlap with this at somepoint.
Afterall it's not uncommon to have these sorts of controls on gpio's
or other pins on a SoC.  Probably just a question of keeping an eye
on progress elsewhere for now...
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
>  drivers/staging/iio/dac/ad5791.c |  122 +++++++++++++++++---------------------
>  1 file changed, 53 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/staging/iio/dac/ad5791.c b/drivers/staging/iio/dac/ad5791.c
> index 8628964..4e955ed 100644
> --- a/drivers/staging/iio/dac/ad5791.c
> +++ b/drivers/staging/iio/dac/ad5791.c
> @@ -72,71 +72,50 @@ static int ad5791_spi_read(struct spi_device *spi, u8 addr, u32 *val)
>  	return ret;
>  }
>  
> -#define AD5791_CHAN(bits, shift) {			\
> -	.type = IIO_VOLTAGE,				\
> -	.output = 1,					\
> -	.indexed = 1,					\
> -	.address = AD5791_ADDR_DAC0,			\
> -	.channel = 0,					\
> -	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |	\
> -		IIO_CHAN_INFO_SCALE_SHARED_BIT |	\
> -		IIO_CHAN_INFO_OFFSET_SHARED_BIT,	\
> -	.scan_type = IIO_ST('u', bits, 24, shift)	\
> -}
> -
> -static const struct iio_chan_spec ad5791_channels[] = {
> -	[ID_AD5760] = AD5791_CHAN(16, 4),
> -	[ID_AD5780] = AD5791_CHAN(18, 2),
> -	[ID_AD5781] = AD5791_CHAN(18, 2),
> -	[ID_AD5791] = AD5791_CHAN(20, 0)
> +static const char * const ad5791_powerdown_modes[] = {
> +	"6kohm_to_gnd",
> +	"three_state",
>  };
>  
> -static ssize_t ad5791_read_powerdown_mode(struct device *dev,
> -				      struct device_attribute *attr, char *buf)
> +static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
> +	const struct iio_chan_spec *chan)
>  {
> -	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct ad5791_state *st = iio_priv(indio_dev);
>  
> -	const char mode[][14] = {"6kohm_to_gnd", "three_state"};
> -
> -	return sprintf(buf, "%s\n", mode[st->pwr_down_mode]);
> +	return st->pwr_down_mode;
>  }
>  
> -static ssize_t ad5791_write_powerdown_mode(struct device *dev,
> -				       struct device_attribute *attr,
> -				       const char *buf, size_t len)
> +static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
> +	const struct iio_chan_spec *chan, unsigned int mode)
>  {
> -	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct ad5791_state *st = iio_priv(indio_dev);
> -	int ret;
>  
> -	if (sysfs_streq(buf, "6kohm_to_gnd"))
> -		st->pwr_down_mode = AD5791_DAC_PWRDN_6K;
> -	else if (sysfs_streq(buf, "three_state"))
> -		st->pwr_down_mode = AD5791_DAC_PWRDN_3STATE;
> -	else
> -		ret = -EINVAL;
> +	st->pwr_down_mode = mode;
>  
> -	return ret ? ret : len;
> +	return 0;
>  }
>  
> -static ssize_t ad5791_read_dac_powerdown(struct device *dev,
> -					   struct device_attribute *attr,
> -					   char *buf)
> +static const struct iio_enum ad5791_powerdown_mode_enum = {
> +	.items = ad5791_powerdown_modes,
> +	.num_items = ARRAY_SIZE(ad5791_powerdown_modes),
> +	.get = ad5791_get_powerdown_mode,
> +	.set = ad5791_set_powerdown_mode,
> +};
> +
> +static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
> +	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
>  {
> -	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct ad5791_state *st = iio_priv(indio_dev);
>  
>  	return sprintf(buf, "%d\n", st->pwr_down);
>  }
>  
> -static ssize_t ad5791_write_dac_powerdown(struct device *dev,
> -					    struct device_attribute *attr,
> -					    const char *buf, size_t len)
> +static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
> +	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
> +	 size_t len)
>  {
>  	long readin;
>  	int ret;
> -	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct ad5791_state *st = iio_priv(indio_dev);
>  
>  	ret = strict_strtol(buf, 10, &readin);
> @@ -160,31 +139,6 @@ static ssize_t ad5791_write_dac_powerdown(struct device *dev,
>  	return ret ? ret : len;
>  }
>  
> -static IIO_DEVICE_ATTR(out_voltage_powerdown_mode, S_IRUGO |
> -			S_IWUSR, ad5791_read_powerdown_mode,
> -			ad5791_write_powerdown_mode, 0);
> -
> -static IIO_CONST_ATTR(out_voltage_powerdown_mode_available,
> -			"6kohm_to_gnd three_state");
> -
> -#define IIO_DEV_ATTR_DAC_POWERDOWN(_num, _show, _store, _addr)		\
> -	IIO_DEVICE_ATTR(out_voltage##_num##_powerdown,			\
> -			S_IRUGO | S_IWUSR, _show, _store, _addr)
> -
> -static IIO_DEV_ATTR_DAC_POWERDOWN(0, ad5791_read_dac_powerdown,
> -				   ad5791_write_dac_powerdown, 0);
> -
> -static struct attribute *ad5791_attributes[] = {
> -	&iio_dev_attr_out_voltage0_powerdown.dev_attr.attr,
> -	&iio_dev_attr_out_voltage_powerdown_mode.dev_attr.attr,
> -	&iio_const_attr_out_voltage_powerdown_mode_available.dev_attr.attr,
> -	NULL,
> -};
> -
> -static const struct attribute_group ad5791_attribute_group = {
> -	.attrs = ad5791_attributes,
> -};
> -
>  static int ad5791_get_lin_comp(unsigned int span)
>  {
>  	if (span <= 10000)
> @@ -254,6 +208,37 @@ static int ad5791_read_raw(struct iio_dev *indio_dev,
>  
>  };
>  
> +static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
> +	{
> +		.name = "powerdown",
> +		.shared = true,
> +		.read = ad5791_read_dac_powerdown,
> +		.write = ad5791_write_dac_powerdown,
> +	},
> +	IIO_ENUM("powerdown_mode", true, &ad5791_powerdown_mode_enum),
> +	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5791_powerdown_mode_enum),
> +	{ },
> +};
> +
> +#define AD5791_CHAN(bits, shift) {			\
> +	.type = IIO_VOLTAGE,				\
> +	.output = 1,					\
> +	.indexed = 1,					\
> +	.address = AD5791_ADDR_DAC0,			\
> +	.channel = 0,					\
> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |	\
> +		IIO_CHAN_INFO_SCALE_SHARED_BIT |	\
> +		IIO_CHAN_INFO_OFFSET_SHARED_BIT,	\
> +	.scan_type = IIO_ST('u', bits, 24, shift),	\
> +	.ext_info = ad5791_ext_info,			\
> +}
> +
> +static const struct iio_chan_spec ad5791_channels[] = {
> +	[ID_AD5760] = AD5791_CHAN(16, 4),
> +	[ID_AD5780] = AD5791_CHAN(18, 2),
> +	[ID_AD5781] = AD5791_CHAN(18, 2),
> +	[ID_AD5791] = AD5791_CHAN(20, 0)
> +};
>  
>  static int ad5791_write_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan,
> @@ -278,7 +263,6 @@ static int ad5791_write_raw(struct iio_dev *indio_dev,
>  static const struct iio_info ad5791_info = {
>  	.read_raw = &ad5791_read_raw,
>  	.write_raw = &ad5791_write_raw,
> -	.attrs = &ad5791_attribute_group,
>  	.driver_module = THIS_MODULE,
>  };
>