diff mbox

[2/2] input: touchscreen: sample averaging for imx6ul_tsc

Message ID 1480232698-23075-2-git-send-email-guy.shapiro@mobi-wize.com (mailing list archive)
State New, archived
Headers show

Commit Message

Guy Shapiro Nov. 27, 2016, 7:44 a.m. UTC 
The i.MX6UL internal touchscreen controller contains an option to
average upon samples. This feature reduces noise from the produced
touch locations.

This patch adds sample averaging support to the imx6ul_tsc device
driver.

Signed-off-by: Guy Shapiro <guy.shapiro@mobi-wize.com>
---
 drivers/input/touchscreen/imx6ul_tsc.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Fabio Estevam Nov. 27, 2016, 12:39 p.m. UTC | #1 
On Sun, Nov 27, 2016 at 5:44 AM, Guy Shapiro <guy.shapiro@mobi-wize.com> wrote:
> The i.MX6UL internal touchscreen controller contains an option to
> average upon samples. This feature reduces noise from the produced
> touch locations.
>
> This patch adds sample averaging support to the imx6ul_tsc device
> driver.
>
> Signed-off-by: Guy Shapiro <guy.shapiro@mobi-wize.com>

Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Dmitry Torokhov Nov. 28, 2016, 4:46 a.m. UTC | #2 
On Sun, Nov 27, 2016 at 10:39:10AM -0200, Fabio Estevam wrote:
> On Sun, Nov 27, 2016 at 5:44 AM, Guy Shapiro <guy.shapiro@mobi-wize.com> wrote:
> > The i.MX6UL internal touchscreen controller contains an option to
> > average upon samples. This feature reduces noise from the produced
> > touch locations.
> >
> > This patch adds sample averaging support to the imx6ul_tsc device
> > driver.
> >
> > Signed-off-by: Guy Shapiro <guy.shapiro@mobi-wize.com>
> 
> Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>

Folded the binding patch into this one and applied, thank you.
diff mbox

Patch

diff --git a/drivers/input/touchscreen/imx6ul_tsc.c b/drivers/input/touchscreen/imx6ul_tsc.c
index 8275267..31724d9 100644
--- a/drivers/input/touchscreen/imx6ul_tsc.c
+++ b/drivers/input/touchscreen/imx6ul_tsc.c
@@ -25,6 +25,7 @@ 
 /* ADC configuration registers field define */
 #define ADC_AIEN		(0x1 << 7)
 #define ADC_CONV_DISABLE	0x1F
+#define ADC_AVGE		(0x1 << 5)
 #define ADC_CAL			(0x1 << 7)
 #define ADC_CALF		0x2
 #define ADC_12BIT_MODE		(0x2 << 2)
@@ -32,6 +33,7 @@ 
 #define ADC_CLK_DIV_8		(0x03 << 5)
 #define ADC_SHORT_SAMPLE_MODE	(0x0 << 4)
 #define ADC_HARDWARE_TRIGGER	(0x1 << 13)
+#define ADC_AVGS_SHIFT		14
 #define SELECT_CHANNEL_4	0x04
 #define SELECT_CHANNEL_1	0x01
 #define DISABLE_CONVERSION_INT	(0x0 << 7)
@@ -86,6 +88,7 @@  struct imx6ul_tsc {
 
 	int measure_delay_time;
 	int pre_charge_time;
+	int average_samples;
 
 	struct completion completion;
 };
@@ -107,6 +110,8 @@  static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
 	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
 	adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
 	adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
+	if (tsc->average_samples)
+		adc_cfg |= (tsc->average_samples - 1) << ADC_AVGS_SHIFT;
 	adc_cfg &= ~ADC_HARDWARE_TRIGGER;
 	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
 
@@ -118,6 +123,8 @@  static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
 	/* start ADC calibration */
 	adc_gc = readl(tsc->adc_regs + REG_ADC_GC);
 	adc_gc |= ADC_CAL;
+	if (tsc->average_samples)
+		adc_gc |= ADC_AVGE;
 	writel(adc_gc, tsc->adc_regs + REG_ADC_GC);
 
 	timeout = wait_for_completion_timeout
@@ -450,6 +457,16 @@  static int imx6ul_tsc_probe(struct platform_device *pdev)
 	if (err)
 		tsc->pre_charge_time = 0xfff;
 
+	err = of_property_read_u32(np, "average-samples",
+				   &tsc->average_samples);
+	if (err)
+		tsc->average_samples = 0;
+	if (tsc->average_samples > 4) {
+		dev_err(&pdev->dev, "average-samples (%u) must be [0-4]\n",
+			tsc->average_samples);
+		return -EINVAL;
+	}
+
 	err = input_register_device(tsc->input);
 	if (err) {
 		dev_err(&pdev->dev,