Re: [PATCHv5 RESEND 2/4] iio: mxs-lradc: add scale_available file to channels

[Jonathan Cameron <jic23@kernel.org>]

On 23/12/13 17:48, Alexandre Belloni wrote:
> From: Hector Palacios <hector.palacios@digi.com>
>
> Adds in_voltageX_scale_available file for every channel to read
> the different available scales.
> There are two scales per channel:
>   [0] = divider_by_two disabled (default)
>   [1] = divider_by_two enabled
> The scale is a struct made of integer and nano parts to build
> a long decimal number.
>
> Signed-off-by: Hector Palacios <hector.palacios@digi.com>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> Acked-by: Marek Vasut <marex@denx.de>
Applied to the togreg branch of iio.git (pushed out as testing for now)

Thanks
>
> ---
>   drivers/staging/iio/adc/mxs-lradc.c | 106 +++++++++++++++++++++++++++++++++++-
>   1 file changed, 105 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index 22fef0a408db..c63b312e54fd 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -38,6 +38,7 @@
>   #include <linux/clk.h>
>
>   #include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
>   #include <linux/iio/buffer.h>
>   #include <linux/iio/trigger.h>
>   #include <linux/iio/trigger_consumer.h>
> @@ -184,6 +185,11 @@ enum lradc_ts_plate {
>   	LRADC_SAMPLE_VALID,
>   };
>
> +struct mxs_lradc_scale {
> +	unsigned int		integer;
> +	unsigned int		nano;
> +};
> +
>   struct mxs_lradc {
>   	struct device		*dev;
>   	void __iomem		*base;
> @@ -199,6 +205,7 @@ struct mxs_lradc {
>   	struct completion	completion;
>
>   	const uint32_t		*vref_mv;
> +	struct mxs_lradc_scale	scale_avail[LRADC_MAX_TOTAL_CHANS][2];
>
>   	/*
>   	 * Touchscreen LRADC channels receives a private slot in the CTRL4
> @@ -929,9 +936,84 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
>   	return -EINVAL;
>   }
>
> +static ssize_t mxs_lradc_show_scale_available_ch(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf,
> +		int ch)
> +{
> +	struct iio_dev *iio = dev_to_iio_dev(dev);
> +	struct mxs_lradc *lradc = iio_priv(iio);
> +	int i, len = 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(lradc->scale_avail[ch]); i++)
> +		len += sprintf(buf + len, "%d.%09u ",
> +			       lradc->scale_avail[ch][i].integer,
> +			       lradc->scale_avail[ch][i].nano);
> +
> +	len += sprintf(buf + len, "\n");
> +
> +	return len;
> +}
> +
> +static ssize_t mxs_lradc_show_scale_available(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	struct iio_dev_attr *iio_attr = to_iio_dev_attr(attr);
> +
> +	return mxs_lradc_show_scale_available_ch(dev, attr, buf,
> +						 iio_attr->address);
> +}
> +
> +#define SHOW_SCALE_AVAILABLE_ATTR(ch)					\
> +static IIO_DEVICE_ATTR(in_voltage##ch##_scale_available, S_IRUGO,	\
> +		       mxs_lradc_show_scale_available, NULL, ch)
> +
> +SHOW_SCALE_AVAILABLE_ATTR(0);
> +SHOW_SCALE_AVAILABLE_ATTR(1);
> +SHOW_SCALE_AVAILABLE_ATTR(2);
> +SHOW_SCALE_AVAILABLE_ATTR(3);
> +SHOW_SCALE_AVAILABLE_ATTR(4);
> +SHOW_SCALE_AVAILABLE_ATTR(5);
> +SHOW_SCALE_AVAILABLE_ATTR(6);
> +SHOW_SCALE_AVAILABLE_ATTR(7);
> +SHOW_SCALE_AVAILABLE_ATTR(8);
> +SHOW_SCALE_AVAILABLE_ATTR(9);
> +SHOW_SCALE_AVAILABLE_ATTR(10);
> +SHOW_SCALE_AVAILABLE_ATTR(11);
> +SHOW_SCALE_AVAILABLE_ATTR(12);
> +SHOW_SCALE_AVAILABLE_ATTR(13);
> +SHOW_SCALE_AVAILABLE_ATTR(14);
> +SHOW_SCALE_AVAILABLE_ATTR(15);
> +
> +static struct attribute *mxs_lradc_attributes[] = {
> +	&iio_dev_attr_in_voltage0_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage1_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage2_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage3_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage4_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage5_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage6_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage7_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage8_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage9_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage10_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage11_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage12_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage13_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage14_scale_available.dev_attr.attr,
> +	&iio_dev_attr_in_voltage15_scale_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group mxs_lradc_attribute_group = {
> +	.attrs = mxs_lradc_attributes,
> +};
> +
>   static const struct iio_info mxs_lradc_iio_info = {
>   	.driver_module		= THIS_MODULE,
>   	.read_raw		= mxs_lradc_read_raw,
> +	.attrs			= &mxs_lradc_attribute_group,
>   };
>
>   static int mxs_lradc_ts_open(struct input_dev *dev)
> @@ -1241,6 +1323,7 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
>   	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
>   			      BIT(IIO_CHAN_INFO_SCALE),		\
>   	.channel = (idx),					\
> +	.address = (idx),					\
>   	.scan_type = {						\
>   		.sign = 'u',					\
>   		.realbits = LRADC_RESOLUTION,			\
> @@ -1386,7 +1469,8 @@ static int mxs_lradc_probe(struct platform_device *pdev)
>   	struct iio_dev *iio;
>   	struct resource *iores;
>   	int ret = 0, touch_ret;
> -	int i;
> +	int i, s;
> +	unsigned int scale_uv;
>
>   	/* Allocate the IIO device. */
>   	iio = devm_iio_device_alloc(dev, sizeof(*lradc));
> @@ -1456,6 +1540,26 @@ static int mxs_lradc_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto err_trig;
>
> +	/* Populate available ADC input ranges */
> +	for (i = 0; i < LRADC_MAX_TOTAL_CHANS; i++) {
> +		for (s = 0; s < ARRAY_SIZE(lradc->scale_avail[i]); s++) {
> +			/*
> +			 * [s=0] = optional divider by two disabled (default)
> +			 * [s=1] = optional divider by two enabled
> +			 *
> +			 * The scale is calculated by doing:
> +			 *   Vref >> (realbits - s)
> +			 * which multiplies by two on the second component
> +			 * of the array.
> +			 */
> +			scale_uv = ((u64)lradc->vref_mv[i] * 100000000) >>
> +				   (iio->channels[i].scan_type.realbits - s);
> +			lradc->scale_avail[i][s].nano =
> +					do_div(scale_uv, 100000000) * 10;
> +			lradc->scale_avail[i][s].integer = scale_uv;
> +		}
> +	}
> +
>   	/* Configure the hardware. */
>   	ret = mxs_lradc_hw_init(lradc);
>   	if (ret)
>