Input: sun4i-ts - allow controlling filter and sensitivity via DT

This commit introduces two new optional device-tree properties:
"tp-sensitive-adjust": adjust sensitivity of pen down detection
"filter-type": select median and averaging filter

The previous fixed defaults, didn't work well for the Olimex
A13-LCD10TS (I have).

Signed-off-by: Jens Thiele <karme@karme.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
index 178d2efb8353..c0116994067d 100644
--- a/drivers/input/touchscreen/sun4i-ts.c
+++ b/drivers/input/touchscreen/sun4i-ts.c
@@ -30,6 +30,10 @@
  * These kinds of heuristics are just asking for trouble (and don't belong
  * in the kernel). So this driver offers straight forward, reliable single
  * touch functionality only.
+ *
+ * s.a. A20 User Manual "1.15 TP" (Documentation/arm/sunxi/README)
+ * (looks like the description in the A20 User Manual v1.3 is better
+ * than the one in the A10 User Manual v.1.5)
  */
 
 #include <linux/err.h>
@@ -246,6 +250,8 @@ static int sun4i_ts_probe(struct platform_device *pdev)
         int error;
         u32 reg;
         bool ts_attached;
+        u32 tp_sensitive_adjust = 15;
+        u32 filter_type = 1;
 
         ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
         if (!ts)
@@ -322,14 +328,20 @@ static int sun4i_ts_probe(struct platform_device *pdev)
                ts->base + TP_CTRL0);
 
         /*
-         * sensitive_adjust = 15 : max, which is not all that sensitive,
+         * tp_sensitive_adjust is an optional property
          * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
          */
-        writel(TP_SENSITIVE_ADJUST(15) | TP_MODE_SELECT(0),
+        of_property_read_u32(np, "allwinner,tp-sensitive-adjust",
+                             &tp_sensitive_adjust);
+        writel(TP_SENSITIVE_ADJUST(tp_sensitive_adjust) | TP_MODE_SELECT(0),
                ts->base + TP_CTRL2);
 
-        /* Enable median filter, type 1 : 5/3 */
-        writel(FILTER_EN(1) | FILTER_TYPE(1), ts->base + TP_CTRL3);
+        /*
+         * Enable median and averaging filter, optional property for
+         * filter type.
+         */
+        of_property_read_u32(np, "allwinner,filter-type", &filter_type);
+        writel(FILTER_EN(1) | FILTER_TYPE(filter_type), ts->base + TP_CTRL3);
 
         /* Enable temperature measurement, period 1953 (2 seconds) */
         writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);