Input: zforce - add regulator handling

It's possible that the controller has an individually switchable power supply.
Therefore add support to control a supplying regulator.

As this is not always the case, the regulator is requested as optional.

Signed-off-by: Heiko Stuebner <heiko.stuebner@bq.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

2 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/zforce_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/zforce_ts.txt
index 2faf1f1fa39e..80c37df940a7 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/zforce_ts.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/zforce_ts.txt
@@ -9,6 +9,9 @@ Required properties:
 - x-size: horizontal resolution of touchscreen
 - y-size: vertical resolution of touchscreen
 
+Optional properties:
+- vdd-supply: Regulator controlling the controller supply
+
 Example:
 
         i2c@00000000 {
@@ -18,6 +21,7 @@ Example:
                         compatible = "neonode,zforce";
                         reg = <0x50>;
                         interrupts = <2 0>;
+                        vdd-supply = <&reg_zforce_vdd>;
 
                         gpios = <&gpio5 6 0>, /* INT */
                                 <&gpio5 9 0>; /* RST */
diff --git a/drivers/input/touchscreen/zforce_ts.c b/drivers/input/touchscreen/zforce_ts.c
index feea85b52fa8..8ba48f5eff7b 100644
--- a/drivers/input/touchscreen/zforce_ts.c
+++ b/drivers/input/touchscreen/zforce_ts.c
@@ -29,6 +29,8 @@
 #include <linux/sysfs.h>
 #include <linux/input/mt.h>
 #include <linux/platform_data/zforce_ts.h>
+#include <linux/regulator/consumer.h>
+#include <linux/delay.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 
@@ -117,6 +119,8 @@ struct zforce_ts {
         const struct zforce_ts_platdata *pdata;
         char                    phys[32];
 
+        struct regulator        *reg_vdd;
+
         bool                    suspending;
         bool                    suspended;
         bool                    boot_complete;
@@ -690,6 +694,11 @@ static void zforce_reset(void *data)
         struct zforce_ts *ts = data;
 
         gpio_set_value(ts->pdata->gpio_rst, 0);
+
+        udelay(10);
+
+        if (!IS_ERR(ts->reg_vdd))
+                regulator_disable(ts->reg_vdd);
 }
 
 static struct zforce_ts_platdata *zforce_parse_dt(struct device *dev)
@@ -765,10 +774,32 @@ static int zforce_probe(struct i2c_client *client,
                 return ret;
         }
 
+        ts->reg_vdd = devm_regulator_get_optional(&client->dev, "vdd");
+        if (IS_ERR(ts->reg_vdd)) {
+                ret = PTR_ERR(ts->reg_vdd);
+                if (ret == -EPROBE_DEFER)
+                        return ret;
+        } else {
+                ret = regulator_enable(ts->reg_vdd);
+                if (ret)
+                        return ret;
+
+                /*
+                 * according to datasheet add 100us grace time after regular
+                 * regulator enable delay.
+                 */
+                udelay(100);
+        }
+
         ret = devm_add_action(&client->dev, zforce_reset, ts);
         if (ret) {
                 dev_err(&client->dev, "failed to register reset action, %d\n",
                         ret);
+
+                /* hereafter the regulator will be disabled by the action */
+                if (!IS_ERR(ts->reg_vdd))
+                        regulator_disable(ts->reg_vdd);
+
                 return ret;
         }