Input: imx6ul_tsc - generalize the averaging property

Make the avarage-samples property a general touchscreen property
rather than imx6ul device specific.

Signed-off-by: Guy Shapiro <guy.shapiro@mobi-wize.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 33 insertions, 19 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt b/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
index a66069f6db66..d4927c202aef 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
@@ -17,13 +17,8 @@ Optional properties:
   This value depends on the touch screen.
 - pre-charge-time: the touch screen need some time to precharge.
   This value depends on the touch screen.
-- average-samples: Number of data samples which are averaged for each read.
-        Valid values 0-4
-        0 =  1 sample
-        1 =  4 samples
-        2 =  8 samples
-        3 = 16 samples
-        4 = 32 samples
+- touchscreen-average-samples: Number of data samples which are averaged for
+  each read. Valid values are 1, 4, 8, 16 and 32.
 
 Example:
         tsc: tsc@02040000 {
@@ -39,6 +34,6 @@ Example:
                 xnur-gpio = <&gpio1 3 GPIO_ACTIVE_LOW>;
                 measure-delay-time = <0xfff>;
                 pre-charge-time = <0xffff>;
-                average-samples = <4>;
+                touchscreen-average-samples = <32>;
                 status = "okay";
         };
diff --git a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
index bccaa4e73045..537643e86f61 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
@@ -14,6 +14,9 @@ Optional properties for Touchscreens:
  - touchscreen-fuzz-pressure    : pressure noise value of the absolute input
                                   device (arbitrary range dependent on the
                                   controller)
+ - touchscreen-average-samples : Number of data samples which are averaged
+                                  for each read (valid values dependent on the
+                                  controller)
  - touchscreen-inverted-x       : X axis is inverted (boolean)
  - touchscreen-inverted-y       : Y axis is inverted (boolean)
  - touchscreen-swapped-x-y      : X and Y axis are swapped (boolean)
diff --git a/drivers/input/touchscreen/imx6ul_tsc.c b/drivers/input/touchscreen/imx6ul_tsc.c
index d2a39120f37f..7098e0a47019 100644
--- a/drivers/input/touchscreen/imx6ul_tsc.c
+++ b/drivers/input/touchscreen/imx6ul_tsc.c
@@ -21,6 +21,7 @@
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/log2.h>
 
 /* ADC configuration registers field define */
 #define ADC_AIEN                (0x1 << 7)
@@ -93,7 +94,8 @@ struct imx6ul_tsc {
 
         u32 measure_delay_time;
         u32 pre_charge_time;
-        u32 average_samples;
+        bool average_enable;
+        u32 average_select;
 
         struct completion completion;
 };
@@ -117,9 +119,9 @@ static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
         adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
         adc_cfg &= ~(ADC_CLK_DIV_MASK | ADC_SAMPLE_MODE_MASK);
         adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
-        if (tsc->average_samples) {
+        if (tsc->average_enable) {
                 adc_cfg &= ~ADC_AVGS_MASK;
-                adc_cfg |= (tsc->average_samples - 1) << ADC_AVGS_SHIFT;
+                adc_cfg |= (tsc->average_select) << ADC_AVGS_SHIFT;
         }
         adc_cfg &= ~ADC_HARDWARE_TRIGGER;
         writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
@@ -132,7 +134,7 @@ 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)
+        if (tsc->average_enable)
                 adc_gc |= ADC_AVGE;
         writel(adc_gc, tsc->adc_regs + REG_ADC_GC);
 
@@ -362,6 +364,7 @@ static int imx6ul_tsc_probe(struct platform_device *pdev)
         int err;
         int tsc_irq;
         int adc_irq;
+        u32 average_samples;
 
         tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
         if (!tsc)
@@ -466,14 +469,27 @@ 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);
+        err = of_property_read_u32(np, "touchscreen-average-samples",
+                                   &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);
+                average_samples = 1;
+
+        switch (average_samples) {
+        case 1:
+                tsc->average_enable = false;
+                tsc->average_select = 0; /* value unused; initialize anyway */
+                break;
+        case 4:
+        case 8:
+        case 16:
+        case 32:
+                tsc->average_enable = true;
+                tsc->average_select = ilog2(average_samples) - 2;
+                break;
+        default:
+                dev_err(&pdev->dev,
+                        "touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
+                        average_samples);
                 return -EINVAL;
         }