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>

diff --git a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
index d59d252..89abecd 100644 (file)
--- a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
@@ -9,8 +9,20 @@ Required properties:
  - #thermal-sensor-cells: shall be 0
 
 Optional properties:
- - allwinner,ts-attached: boolean indicating that an actual touchscreen is
-                         attached to the controller
+ - allwinner,ts-attached        : boolean indicating that an actual touchscreen
+                                  is attached to the controller
+ - allwinner,tp-sensitive-adjust : integer (4 bits)
+                                  adjust sensitivity of pen down detection
+                                  between 0 (least sensitive) and 15
+                                  (defaults to 15)
+ - allwinner,filter-type        : integer (2 bits)
+                                  select median and averaging filter
+                                  samples used for median / averaging filter
+                                  0: 4/2
+                                  1: 5/3
+                                  2: 8/4
+                                  3: 16/8
+                                  (defaults to 1)
 
 Example:
 
@@ -20,4 +32,7 @@ Example:
                interrupts = <29>;
                allwinner,ts-attached;
                #thermal-sensor-cells = <0>;
+               /* sensitive/noisy touch panel */
+               allwinner,tp-sensitive-adjust = <0>;
+               allwinner,filter-type = <3>;
        };

diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
index 178d2ef..c011699 100644 (file)
--- 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);