Re: [PATCH 4/5] iio/ti_am335x_adc: Allow to specify input line

[Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On 05/29/2013 06:09 PM, Sebastian Andrzej Siewior wrote:
> The TSC part allows to specify the input lines. The IIO part assumes
> that it usues always the last few, that means if IIO has adc-channels
> set to 2 it will use channel 6 and 7. However it might make sense to use
> only 6.
> This patch changes the device property (which was introduced recently
> and was never in an official release) in a way that the user can specify
> which of the AIN lines should be used. In Addition to this, the name is
> now AINx where x is the channel number i.e. for AIN6 we would have 6.
> Prior this, it always started counting at 0 which is confusing. In
> addition to this, it also checks for correct step number during reading
> and does not rely on proper FIFO depth.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
One nit pick below.
> ---
>  .../bindings/input/touchscreen/ti-tsc-adc.txt      |    5 +-
>  arch/arm/boot/dts/am335x-evm.dts                   |    2 +-
>  drivers/iio/adc/ti_am335x_adc.c                    |   59 +++++++++++++-------
>  drivers/mfd/ti_am335x_tscadc.c                     |   20 ++++++-
>  4 files changed, 60 insertions(+), 26 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> index 80e04e3..204c9cc 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> @@ -25,7 +25,8 @@
>  			AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
>  			XP  = 0, XN = 1, YP = 2, YN = 3.
>  - child "adc"
> -	ti,adc-channels: Number of analog inputs available for ADC
> +	ti,adc-channels: List of analog inputs available for ADC.
> +			 AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
>
>  Example:
>  	tscadc: tscadc@44e0d000 {
> @@ -38,6 +39,6 @@
>  		};
>
>  		adc {
> -			ti,adc-channels = <4>;
> +			ti,adc-channels = <4 5 6 7>;
>  		};
>  	}
> diff --git a/arch/arm/boot/dts/am335x-evm.dts b/arch/arm/boot/dts/am335x-evm.dts
> index 26fea97..0fa4c7f 100644
> --- a/arch/arm/boot/dts/am335x-evm.dts
> +++ b/arch/arm/boot/dts/am335x-evm.dts
> @@ -255,6 +255,6 @@
>  	};
>
>  	adc {
> -		ti,adc-channels = <4>;
> +		ti,adc-channels = <4 5 6 7>;
>  	};
>  };
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index 2988840..df2de4c 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -33,6 +33,8 @@
>  struct tiadc_device {
>  	struct ti_tscadc_dev *mfd_tscadc;
>  	int channels;
> +	u8 channel_line[8];
> +	u8 channel_step[8];
>  	char *buf;
>  	struct iio_map *map;
>  };
> @@ -55,7 +57,7 @@ static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
>  static void tiadc_step_config(struct tiadc_device *adc_dev)
>  {
>  	unsigned int stepconfig;
> -	int i, channels = 0, steps;
> +	int i, steps;
>
>  	/*
>  	 * There are 16 configurable steps and 8 analog input
> @@ -68,16 +70,18 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)
>  	 */
>
>  	steps = TOTAL_STEPS - adc_dev->channels;
> -	channels = TOTAL_CHANNELS - adc_dev->channels;
> -
>  	stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
>
> -	for (i = steps; i < TOTAL_STEPS; i++) {
> -		tiadc_writel(adc_dev, REG_STEPCONFIG(i),
> -				stepconfig | STEPCONFIG_INP(channels));
> -		tiadc_writel(adc_dev, REG_STEPDELAY(i),
> +	for (i = 0; i < adc_dev->channels; i++) {
> +		int chan;
> +
> +		chan = adc_dev->channel_line[i];
> +		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
> +				stepconfig | STEPCONFIG_INP(chan));
> +		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
>  				STEPCONFIG_OPENDLY);
> -		channels++;
> +		adc_dev->channel_step[i] = steps;
> +		steps++;
>  	}
>  	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
>  }
> @@ -101,11 +105,11 @@ static int tiadc_channel_init(struct iio_dev *indio_dev,
>  	chan = chan_array;
>  	for (i = 0; i < channels; i++, chan++, s += len + 1) {
>
> -		len = sprintf(s, "AIN%d", i);
> +		len = sprintf(s, "AIN%d", adc_dev->channel_line[i]);
>
>  		chan->type = IIO_VOLTAGE;
>  		chan->indexed = 1;
> -		chan->channel = i;
> +		chan->channel = adc_dev->channel_line[i];
>  		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>  		chan->datasheet_name = s;
>  		chan->scan_type.sign = 'u';
> @@ -155,7 +159,8 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
>  {
>  	struct tiadc_device *adc_dev = iio_priv(indio_dev);
>  	int i;
> -	unsigned int fifo1count, readx1;
> +	unsigned int fifo1count, read;
> +	u32 step = UINT_MAX;
>
>  	/*
>  	 * When the sub-system is first enabled,
> @@ -168,11 +173,20 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
>  	 * Hence we need to flush out this data.
>  	 */
>
> +	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
> +		if (chan->channel == adc_dev->channel_line[i]) {
> +			step = adc_dev->channel_step[i];
> +			break;
> +		}
> +	}
> +	if (WARN_ON_ONCE(step == UINT_MAX))
> +		return -EINVAL;
> +
>  	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
>  	for (i = 0; i < fifo1count; i++) {
> -		readx1 = tiadc_readl(adc_dev, REG_FIFO1);
> -		if (i == chan->channel)
> -			*val = readx1 & 0xfff;
> +		read = tiadc_readl(adc_dev, REG_FIFO1);
> +		if (read >> 16 == step)
> +			*val = read & 0xfff;
>  	}
>  	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
>
> @@ -189,8 +203,11 @@ static int tiadc_probe(struct platform_device *pdev)
>  	struct tiadc_device	*adc_dev;
>  	struct ti_tscadc_dev	*tscadc_dev = pdev->dev.platform_data;
>  	struct device_node	*node = tscadc_dev->dev->of_node;
> +	struct property		*prop;
> +	const __be32		*cur;
>  	int			err;
> -	u32			val32;
> +	u32			val;
> +	int channels		= 0;
>
>  	if (!node) {
>  		dev_err(&pdev->dev, "Could not find valid DT data.\n");
> @@ -212,11 +229,13 @@ static int tiadc_probe(struct platform_device *pdev)
>  		err = -EINVAL;
>  		goto err_free_device;
>  	}
> -	err = of_property_read_u32(node,
> -			"ti,adc-channels", &val32);
> -	if (err < 0)
> -		goto err_free_device;
> -	adc_dev->channels = val32;
> +
> +	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
> +
> +		adc_dev->channel_line[channels] = val;
> +		channels++;
> +	}
> +	adc_dev->channels = channels;
>
>  	indio_dev->dev.parent = &pdev->dev;
>  	indio_dev->name = dev_name(&pdev->dev);
> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
> index 5e4076f..b228c41 100644
> --- a/drivers/mfd/ti_am335x_tscadc.c
> +++ b/drivers/mfd/ti_am335x_tscadc.c
> @@ -66,9 +66,13 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	struct clk		*clk;
>  	struct device_node	*node = pdev->dev.of_node;
>  	struct mfd_cell		*cell;
> +	struct property         *prop;
> +	const __be32            *cur;
> +	u32			val;
>  	int			err, ctrl;
>  	int			clk_value, clock_rate;
>  	int			tsc_wires = 0, adc_channels = 0, total_channels;
> +	int			readouts = 0;
>
>  	if (!pdev->dev.of_node) {
>  		dev_err(&pdev->dev, "Could not find valid DT data.\n");
> @@ -77,16 +81,26 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>
>  	node = of_get_child_by_name(pdev->dev.of_node, "tsc");
>  	of_property_read_u32(node, "ti,wires", &tsc_wires);
> +	of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
>
>  	node = of_get_child_by_name(pdev->dev.of_node, "adc");
> -	of_property_read_u32(node, "ti,adc-channels", &adc_channels);
> -
> +	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
> +		adc_channels++;
> +		if (val > 7) {
> +			dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
> +					val);
> +			return -EINVAL;
> +		}
> +	}
>  	total_channels = tsc_wires + adc_channels;
> -
Should not change this whitespace in this sort of patch.
>  	if (total_channels > 8) {
>  		dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
>  		return -EINVAL;
>  	}
> +	if (readouts * 2 + 2 + adc_channels > 16) {
> +		dev_err(&pdev->dev, "Too many step configurations requested\n");
> +		return -EINVAL;
> +	}
>
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	if (!res) {
>