Hi Michael,
+ Dmitry
On 08/12/2015 12:15 AM, Michael Welling wrote:
> Adds a device tree parameter to set the open delay on the touchscreen
> conversion steps. Increasing this parameter helps the touch accuracy on
> some screens.
>
> Signed-off-by: Michael Welling <mwelling@xxxxxxxx>
> ---
> .../bindings/input/touchscreen/ti-tsc-adc.txt | 5 +++++
> drivers/input/touchscreen/ti_am335x_tsc.c | 18 ++++++++++++++----
> 2 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> index b1163bf..cb11fda 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> @@ -41,6 +41,11 @@ Optional properties:
> charge step, so this does in fact function as a
> hardware knob for adjusting the amount of "settling
> time".
> + ti,open-delay: Open delay applied to all touchscreen conversion steps.
> + The value corresponds to the number of ADC clock
> + cycles to wait after applying the step configuration
> + registers and before sending the start of ADC
> + conversion. Maximum value is 0x3FFFF.
>
Since open-delay is per step, is it not better to allow specifying
open-delay per step like ti,chan-step-opendelay of adc? This will help
control open-delay for all the four wires.
> - child "adc"
> ti,chan-step-opendelay: List of open delays for each channel of
> diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
> index 191a1b8..37a9729 100644
> --- a/drivers/input/touchscreen/ti_am335x_tsc.c
> +++ b/drivers/input/touchscreen/ti_am335x_tsc.c
> @@ -54,6 +54,7 @@ struct titsc {
> u32 inp_xp, inp_xn, inp_yp, inp_yn;
> u32 step_mask;
> u32 charge_delay;
> + u32 open_delay;
> };
>
> static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
> @@ -148,7 +149,7 @@ static void titsc_step_config(struct titsc *ts_dev)
> end_step = first_step + tsc_steps;
> for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
> titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
> - titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
> + titsc_writel(ts_dev, REG_STEPDELAY(i), ts_dev->open_delay);
> }
>
> config = 0;
> @@ -172,7 +173,7 @@ static void titsc_step_config(struct titsc *ts_dev)
> end_step = first_step + ts_dev->coordinate_readouts;
> for (i = first_step; i < end_step; i++) {
> titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
> - titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
> + titsc_writel(ts_dev, REG_STEPDELAY(i), ts_dev->open_delay);
> }
>
> /* Make CHARGECONFIG same as IDLECONFIG */
> @@ -188,13 +189,13 @@ static void titsc_step_config(struct titsc *ts_dev)
> STEPCONFIG_INP(ts_dev->inp_xp);
> titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
> titsc_writel(ts_dev, REG_STEPDELAY(end_step),
> - STEPCONFIG_OPENDLY);
> + ts_dev->open_delay);
>
> end_step++;
> config |= STEPCONFIG_INP(ts_dev->inp_yn);
> titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
> titsc_writel(ts_dev, REG_STEPDELAY(end_step),
> - STEPCONFIG_OPENDLY);
> + ts_dev->open_delay);
>
> /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
> stepenable = 1;
> @@ -392,6 +393,15 @@ static int titsc_parse_dt(struct platform_device *pdev,
> dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
> }
>
> + err = of_property_read_u32(node, "ti,open-delay",
> + &ts_dev->open_delay);
> + /*
> + * If ti,open-delay value is not specified, then use
> + * STEPCONFIG_OPENDLY as the default value.
> + */
> + if (err < 0)
> + ts_dev->open_delay = STEPCONFIG_OPENDLY;
> +
> return of_property_read_u32_array(node, "ti,wire-config",
> ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
> }
>
--
Regards
Vignesh
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