Re: [PATCH V3 1/2] tps6507x-ts: Add DT support

[Dmitry Torokhov]

Hi Manish,

On Tue, May 21, 2013 at 02:24:17PM +0530, Vishwanathrao Badarkhe, Manish wrote:
> Add device tree based support for TI's tps6507x touchscreen.
> 
> Tested on da850-evm.
> 
> Signed-off-by: Vishwanathrao Badarkhe, Manish <manishv.b@xxxxxx>
> ---
> Changes since V2:
>  - Removed unnecessary code.
>  - Updated Documentation to provide proper names of
>    devicetree properties.
> 
> Changes since V1:
>  - Updated documentation to specify tps6507x as multifunctional
>    device.
>  - return proper error value in absence of platform and DT
>    data for touchscreen.
>  - Updated commit message.
> 
> :100755 100755 8fffa3c... 65ee2cd... M	Documentation/devicetree/bindings/mfd/tps6507x.txt
> :100644 100644 65e0f9a... 89232ee... M	drivers/input/touchscreen/tps6507x-ts.c
>  Documentation/devicetree/bindings/mfd/tps6507x.txt |   28 ++++++-
>  drivers/input/touchscreen/tps6507x-ts.c            |   98 ++++++++++++++------
>  2 files changed, 95 insertions(+), 31 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/tps6507x.txt b/Documentation/devicetree/bindings/mfd/tps6507x.txt
> index 8fffa3c..65ee2cd 100755
> --- a/Documentation/devicetree/bindings/mfd/tps6507x.txt
> +++ b/Documentation/devicetree/bindings/mfd/tps6507x.txt
> @@ -1,4 +1,8 @@
> -TPS6507x Power Management Integrated Circuit
> +TPS6507x Multifunctional Device.
> +
> +Features provided by TPS6507x:
> +        1.Power Management Integrated Circuit.
> +        2.Touch-Screen.
>  
>  Required properties:
>  - compatible: "ti,tps6507x"
> @@ -23,6 +27,12 @@ Required properties:
>         vindcdc1_2-supply: VDCDC1 and VDCDC2 input.
>         vindcdc3-supply  : VDCDC3 input.
>         vldo1_2-supply   : VLDO1 and VLDO2 input.
> +- tsc: This node specifies touch screen data.
> +	ti,poll-period : Time at which touch input is getting sampled in ms.
> +	ti,min-pressure: Minimum pressure value to trigger touch.
> +	ti,vref	       : voltage reference for ADC.
> +		      0: Reference voltage for ADC is disabled.
> +		      1: Reference voltage for ADC is enabled.
>  
>  Regulator Optional properties:
>  - defdcdc_default: It's property of DCDC2 and DCDC3 regulators.
> @@ -30,6 +40,14 @@ Regulator Optional properties:
>  			1: If defdcdc pin of DCDC2/DCDC3 is driven HIGH.
>    If this property is not defined, it defaults to 0 (not enabled).
>  
> +Touchscreen Optional properties:
> +- ti,vendor : Touchscreen vendor id to populate
> +	      in sysclass interface.
> +- ti,product: Touchscreen product id to populate
> +	      in sysclass interface.
> +- ti,version: Touchscreen version id to populate
> +	      in sysclass interface.
> +
>  Example:
>  
>  	pmu: tps6507x@48 {
> @@ -88,4 +106,12 @@ Example:
>  			};
>  		};
>  
> +		tsc {
> +			ti,poll-period = <30>;
> +			ti,min-pressure = <0x30>;
> +			ti,vref = <0>;
> +			ti,vendor = <0>;
> +			ti,product = <65070>;
> +			ti,version = <0x100>;
> +		};
>  	};
> diff --git a/drivers/input/touchscreen/tps6507x-ts.c b/drivers/input/touchscreen/tps6507x-ts.c
> index 65e0f9a..89232ee 100644
> --- a/drivers/input/touchscreen/tps6507x-ts.c
> +++ b/drivers/input/touchscreen/tps6507x-ts.c
> @@ -21,6 +21,8 @@
>  #include <linux/mfd/tps6507x.h>
>  #include <linux/input/tps6507x-ts.h>
>  #include <linux/delay.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  
>  #define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
>  #define TPS_DEFAULT_MIN_PRESSURE 0x30
> @@ -231,36 +233,76 @@ done:
>  	ret = tps6507x_adc_standby(tsc);
>  }
>  
> +static int tsc_init_data(struct tps6507x_dev *tps6507x_dev,
> +		struct input_dev *input_dev)
> +{
> +	struct device_node *node = tps6507x_dev->dev->of_node;
> +	struct tps6507x_board *tps_board =
> +		(struct tps6507x_board *)tps6507x_dev->dev->platform_data;


Please make tps_board const pointer and use dev_get_platdata() to fetch
it.

> +	struct touchscreen_init_data *init_data = NULL;
> +	int err;
> +
> +	if (node)
> +		node = of_find_node_by_name(node, "tsc");

Why do you have to locate OF node manually instead of already having it
attached to the device stucture?

> +	if (tps_board)
> +		init_data = tps_board->tps6507x_ts_init_data;
> +
> +	if (node == NULL || init_data == NULL) {
> +		err = -EINVAL;
> +		goto error_ret;
> +	} else if (init_data) {
> +		tps6507x_dev->ts->poll_period = init_data->poll_period;
> +		tps6507x_dev->ts->min_pressure = init_data->min_pressure;
> +		tps6507x_dev->ts->vref = init_data->vref;
> +		input_dev->id.vendor = init_data->vendor;
> +		input_dev->id.product = init_data->product;
> +		input_dev->id.version = init_data->version;
> +	} else if (node) {
> +		err = of_property_read_u32(node, "ti,poll-period",
> +					(u32 *)&tps6507x_dev->ts->poll_period);
> +		if (err < 0)
> +			goto error_ret;
> +
> +		err = of_property_read_u16(node, "ti,min-pressure",
> +					&tps6507x_dev->ts->min_pressure);
> +		if (err < 0)
> +			goto error_ret;
> +
> +		err = of_property_read_u32(node, "ti,vref",
> +					&tps6507x_dev->ts->vref);

I do not think it is used anywhere, see a patch I just sent out.

> +		if (err < 0)
> +			goto error_ret;
> +
> +		err = of_property_read_u16(node, "ti,vendor",
> +					&input_dev->id.vendor);
> +		if (err < 0)
> +			goto error_ret;
> +
> +		err = of_property_read_u16(node, "ti,product",
> +					&input_dev->id.product);
> +		if (err < 0)
> +			goto error_ret;
> +
> +		err = of_property_read_u16(node, "ti,version",
> +					&input_dev->id.version);

You say these 3 properties are optional, so why do you err out if you
fail to read them?

> +		if (err < 0)
> +			goto error_ret;
> +	}
> +
> +	return 0;
> +
> +error_ret:
> +	return err;
> +}
> +
>  static int tps6507x_ts_probe(struct platform_device *pdev)
>  {
>  	int error;
>  	struct tps6507x_ts *tsc;
>  	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
> -	struct touchscreen_init_data *init_data;
>  	struct input_dev *input_dev;
> -	struct tps6507x_board *tps_board;
>  	int schd;
>  
> -	/**
> -	 * tps_board points to pmic related constants
> -	 * coming from the board-evm file.
> -	 */
> -
> -	tps_board = (struct tps6507x_board *)tps6507x_dev->dev->platform_data;
> -
> -	if (!tps_board) {
> -		dev_err(tps6507x_dev->dev,
> -			"Could not find tps6507x platform data\n");
> -		return -EIO;
> -	}
> -
> -	/**
> -	 * init_data points to array of regulator_init structures
> -	 * coming from the board-evm file.
> -	 */
> -
> -	init_data = tps_board->tps6507x_ts_init_data;
> -
>  	tsc = devm_kzalloc(&pdev->dev, sizeof(struct tps6507x_ts), GFP_KERNEL);
>  	if (!tsc) {
>  		dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
> @@ -301,14 +343,10 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
>  
>  	INIT_DELAYED_WORK(&tsc->work, tps6507x_ts_handler);
>  
> -	if (init_data) {
> -		tsc->poll_period = init_data->poll_period;
> -		tsc->vref = init_data->vref;
> -		tsc->min_pressure = init_data->min_pressure;
> -		input_dev->id.vendor = init_data->vendor;
> -		input_dev->id.product = init_data->product;
> -		input_dev->id.version = init_data->version;
> -	} else {
> +	error = tsc_init_data(tps6507x_dev, input_dev);
> +
> +	if (error) {
> +		dev_warn(&pdev->dev, "Use default platform data\n");

Why do we have to warn here?

Also, this is not reqlly equivalent transformation of the old code,
which allowed to partially specify init data and would substitute some
of it with defaults.

>  		tsc->poll_period = TSC_DEFAULT_POLL_PERIOD;
>  		tsc->min_pressure = TPS_DEFAULT_MIN_PRESSURE;
>  	}
> -- 
> 1.7.4.1
> 

Thanks.

-- 
Dmitry
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