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. - 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)); } -- 2.1.4 -- 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