Re: [PATCH v3 6/8] drivers:input:ads7846(+tsc2046): add new common binding names, pre-calibration and flipping

[Rob Herring <robh@kernel.org>]

On Fri, Sep 23, 2016 at 02:41:14PM +0200, H. Nikolaus Schaller wrote:
> commit b98abe52fa8e ("Input: add common DT binding for touchscreens")
> introduced common DT bindings for touchscreens [1] and a helper function to
> parse the DT.
> 
> commit ed7c9870c9bc ("Input: of_touchscreen - add support for inverted / swapped axes")
> added another helper for parsing axis inversion and swapping
> and applying them to x and y coordinates.
> 
> Both helpers have been integrated to accommodate any orientation of the
> touch panel in relation to the LCD.
> 
> A new feature is to introduce scaling the min/max ADC values to the screen
> size.
> 
> This makes it possible to pre-calibrate the touch so that is (almost)
> exactly matches the LCD pixel coordinates it is glued onto. This allows to
> well enough operate the touch before a user space calibration step can
> improve the precision.

This appears to be the prior patch's commit msg, or you don't need ADC 
values in DT for this one?

> 
> [1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
> 
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
>  .../devicetree/bindings/input/ads7846.txt          |  9 +++-
>  drivers/input/touchscreen/ads7846.c                | 60 ++++++++++++++++++----
>  2 files changed, 57 insertions(+), 12 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/input/ads7846.txt b/Documentation/devicetree/bindings/input/ads7846.txt
> index 9fc47b0..29f91ed 100644
> --- a/Documentation/devicetree/bindings/input/ads7846.txt
> +++ b/Documentation/devicetree/bindings/input/ads7846.txt
> @@ -26,6 +26,12 @@ Additional required properties:
>  
>  Optional properties:
>  
> +You can optionally specify any of the touchscreen parameters described in
> +
> +	Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
> +
> +This allows to scale, invert or swap coordinates and define the fuzz factors.
> +
>  	ti,vref-delay-usecs		vref supply delay in usecs, 0 for
>  					external vref (u16).
>  	ti,vref-mv			The VREF voltage, in millivolts (u16).
> @@ -33,7 +39,7 @@ Optional properties:
>  					(ADS7846).
>  	ti,keep-vref-on			set to keep vref on for differential
>  					measurements as well
> -	ti,swap-xy			swap x and y axis
> +	ti,swap-xy			deprecated name for touchscreen-swapped-x-y
>  	ti,settle-delay-usec		Settling time of the analog signals;
>  					a function of Vcc and the capacitance
>  					on the X/Y drivers.  If set to non-zero,
> @@ -82,6 +88,7 @@ Example for a TSC2046 chip connected to an McSPI controller of an OMAP SoC::
>  			pendown-gpio = <&gpio1 8 0>;
>  			vcc-supply = <&reg_vcc3>;
>  
> +			touchscreen-swapped-x-y;
>  			ti,x-min = /bits/ 16 <0>;
>  			ti,x-max = /bits/ 16 <8000>;
>  			ti,y-min = /bits/ 16 <0>;
> diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
> index 1ce3ecb..400e421 100644
> --- a/drivers/input/touchscreen/ads7846.c
> +++ b/drivers/input/touchscreen/ads7846.c
> @@ -34,6 +34,7 @@
>  #include <linux/spi/ads7846.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/module.h>
> +#include <linux/input/touchscreen.h>
>  #include <asm/irq.h>
>  
>  /*
> @@ -109,8 +110,13 @@ struct ads7846 {
>  	u16			vref_delay_usecs;
>  	u16			x_plate_ohms;
>  	u16			pressure_max;
> +	u16			x_min;
> +	u16			x_max;
> +	u16			y_min;
> +	u16			y_max;
> +
> +	struct touchscreen_properties prop;
>  
> -	bool			swap_xy;
>  	bool			use_internal;
>  
>  	struct ads7846_packet	*packet;
> @@ -825,22 +831,36 @@ static void ads7846_report_state(struct ads7846 *ts)
>  	 */
>  	if (Rt) {
>  		struct input_dev *input = ts->input;
> +		int sx, sy;
> +
> +		dev_dbg(&ts->spi->dev,
> +			"Raw point(%4d,%4d), pressure (%4u)\n",
> +				x, y, Rt);
> +
> +		/* scale ADC values to desired output range */
> +		sx = (ts->prop.max_x * (x - ts->x_min))
> +			/ (ts->x_max - ts->x_min);
> +		sy = (ts->prop.max_y * (y - ts->y_min))
> +			/ (ts->y_max - ts->y_min);
>  
> -		if (ts->swap_xy)
> -			swap(x, y);
> +		dev_dbg(&ts->spi->dev,
> +			"Scaled point(%4d,%4d), pressure (%4u)\n",
> +				sx, sy, Rt);
>  
> +		/* report event */
>  		if (!ts->pendown) {
>  			input_report_key(input, BTN_TOUCH, 1);
>  			ts->pendown = true;
>  			dev_vdbg(&ts->spi->dev, "DOWN\n");
>  		}
>  
> -		input_report_abs(input, ABS_X, x);
> -		input_report_abs(input, ABS_Y, y);
> +		touchscreen_report_pos(ts->input, &ts->prop,
> +				       (unsigned int) sx, (unsigned int) sy,
> +				       false);
>  		input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
>  
>  		input_sync(input);
> -		dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
> +		dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", sx, sy, Rt);
>  	}
>  }
>  
> @@ -1212,6 +1232,8 @@ static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
>  	pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
>  
>  	pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
> +	if (pdata->swap_xy)
> +		dev_notice(dev, "please update device tree to use touchscreen-swapped-x-y");
>  
>  	of_property_read_u16(node, "ti,settle-delay-usec",
>  			     &pdata->settle_delay_usecs);
> @@ -1315,7 +1337,6 @@ static int ads7846_probe(struct spi_device *spi)
>  	ts->pressure_max = pdata->pressure_max ? : ~0;
>  
>  	ts->vref_mv = pdata->vref_mv;
> -	ts->swap_xy = pdata->swap_xy;
>  
>  	if (pdata->filter != NULL) {
>  		if (pdata->filter_init != NULL) {
> @@ -1355,18 +1376,35 @@ static int ads7846_probe(struct spi_device *spi)
>  	input_dev->dev.parent = &spi->dev;
>  
>  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> +	input_dev->absbit[0] = BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
> +				BIT_MASK(ABS_PRESSURE);
>  	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> +
> +	ts->x_min = pdata->x_min ? : 0;
> +	ts->x_max = pdata->x_max ? : MAX_12BIT;
> +	ts->y_min = pdata->y_min ? : 0;
> +	ts->y_max = pdata->y_max ? : MAX_12BIT;
> +
>  	input_set_abs_params(input_dev, ABS_X,
> -			pdata->x_min ? : 0,
> -			pdata->x_max ? : MAX_12BIT,
> +			ts->x_min,
> +			ts->x_max,
>  			0, 0);
>  	input_set_abs_params(input_dev, ABS_Y,
> -			pdata->y_min ? : 0,
> -			pdata->y_max ? : MAX_12BIT,
> +			ts->y_min,
> +			ts->y_max,
>  			0, 0);
>  	input_set_abs_params(input_dev, ABS_PRESSURE,
>  			pdata->pressure_min, pdata->pressure_max, 0, 0);
>  
> +	if (spi->dev.of_node) {
> +		input_abs_set_min(input_dev, ABS_X, 0);
> +		input_abs_set_min(input_dev, ABS_Y, 0);
> +
> +		touchscreen_parse_properties(ts->input, false, &ts->prop);
> +	}
> +
> +	ts->prop.swap_x_y |= pdata->swap_xy;
> +
>  	ads7846_setup_spi_msg(ts, pdata);
>  
>  	ts->reg = regulator_get(&spi->dev, "vcc");
> -- 
> 2.7.3
> 
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