On Thu, Aug 20, 2015 at 05:41:30PM +0530, Vignesh R wrote: > > > On 08/19/2015 11:38 PM, Michael Welling wrote: > > On Wed, Aug 12, 2015 at 01:44:22PM -0500, Michael Welling wrote: > >> 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? > > > Sorry for the delay, > > I haven't seen different delays being used for different channels on > 4-wire TSC ( not sure of 5-wire or 8 wire designs). Since this is DT > change, I just wanted to make sure more flexibility is provided. > > >> > >> The user would need to know the number of steps what each of the steps do. > >> > > > What I was thinking was making open-delay configurable per channel (one > entry for X+, X-, Y+, Y-). > > For example, for a 4-wire TSC: > ti,chan-open-delay = <0x30 0x100 0x20 0x10>; /* for X+, X-, Y+, Y- */ > What about the readings for the pressure? > > >>> > >>>> - 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 > > -- > Regards > Vignesh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html