On Wed, Aug 12, 2015 at 11:56:36AM +0530, Vignesh R wrote:
> 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.
Do you see any reason why you would want a different delay for each step of
the conversion on the same touchscreen?
The user would need to know the number of steps what each of the steps do.
>
> > - 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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