input: ft5x06: Add support for clocks for secure touch on 8937 QRD

Because of a change in the underlying bus driver, the secure touch
layer in the input drivers is now required to control directly the
clocks which are needed during the touch sessions. The clocks which
are associated with the underlying I2C bus are clk_gcc_blsp1_ahb_clk
and clk_gcc_blsp1_qup3_i2c_apps_clk. These clocks are turned on/off
when the secure touch session is started/ended.

Change-Id: If5abca579e264cc7799310628c4e379ac4368e7e
Signed-off-by: Abinaya P <abinayap@codeaurora.org>

Documentation/devicetree/bindings/input/touchscreen/ft5x06-ts.txt

@@ -72,6 +72,9 @@ Optional properties:
  - focaltech,psensor-support	: specify whether support the proximity sensor
  - focaltech,gesture-support	: specify whether support gesture feature
  - focaltech,resume-in-workqueue : specifiy whether to defer the resume to workqueue
+ - clock-names:               : Clock names used for secure touch. They are: "iface_clk", "core_clk"
+ - clocks                        : Defined if 'clock-names' DT property is defined. These clocks
+				   are associated with the underlying I2C bus.
 
 Example:
 	i2c@f9923000{
@@ -109,5 +112,9 @@ Example:
 			focaltech,fw-auto-cal;
 			focaltech,psensor-support;
 			focaltech,gesture-support;
+			/* Underlying clocks used by secure touch */
+			clock-names = "iface_clk", "core_clk";
+			clocks = <&clock_gcc clk_gcc_blsp1_ahb_clk>,
+			<&clock_gcc clk_gcc_blsp1_qup3_i2c_apps_clk>;
 		};
 	};

drivers/input/touchscreen/ft5x06_ts.c

@@ -50,7 +50,9 @@
 #if defined(CONFIG_FT_SECURE_TOUCH)
 #include <linux/completion.h>
 #include <linux/atomic.h>
+#include <linux/clk.h>
 #include <linux/pm_runtime.h>
+static irqreturn_t ft5x06_ts_interrupt(int irq, void *data);
 #endif
 
 #define FT_DRIVER_VERSION	0x02
@@ -276,6 +278,9 @@ struct ft5x06_ts_data {
 	atomic_t st_pending_irqs;
 	struct completion st_powerdown;
 	struct completion st_irq_processed;
+	bool st_initialized;
+	struct clk *core_clk;
+	struct clk *iface_clk;
 #endif
 };
 
@@ -285,8 +290,26 @@ static int ft5x06_ts_stop(struct device *dev);
 #if defined(CONFIG_FT_SECURE_TOUCH)
 static void ft5x06_secure_touch_init(struct ft5x06_ts_data *data)
 {
+	data->st_initialized = 0;
+
 	init_completion(&data->st_powerdown);
 	init_completion(&data->st_irq_processed);
+
+	/* Get clocks */
+	data->core_clk = devm_clk_get(&data->client->dev, "core_clk");
+	if (IS_ERR(data->core_clk)) {
+		data->core_clk = NULL;
+		dev_warn(&data->client->dev,
+			"%s: core_clk is not defined\n", __func__);
+	}
+
+	data->iface_clk = devm_clk_get(&data->client->dev, "iface_clk");
+	if (IS_ERR(data->iface_clk)) {
+		data->iface_clk = NULL;
+		dev_warn(&data->client->dev,
+			"%s: iface_clk is not defined", __func__);
+	}
+	data->st_initialized = 1;
 }
 
 static void ft5x06_secure_touch_notify(struct ft5x06_ts_data *data)
@@ -324,12 +347,43 @@ static void ft5x06_secure_touch_stop(struct ft5x06_ts_data *data, bool blocking)
 	}
 }
 
+static int ft5x06_clk_prepare_enable(struct ft5x06_ts_data *data)
+{
+	int ret;
+
+	ret = clk_prepare_enable(data->iface_clk);
+	if (ret) {
+		dev_err(&data->client->dev,
+			"error on clk_prepare_enable(iface_clk):%d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(data->core_clk);
+	if (ret) {
+		clk_disable_unprepare(data->iface_clk);
+		dev_err(&data->client->dev,
+			"error clk_prepare_enable(core_clk):%d\n", ret);
+	}
+	return ret;
+}
+
+static void ft5x06_clk_disable_unprepare(struct ft5x06_ts_data *data)
+{
+	clk_disable_unprepare(data->core_clk);
+	clk_disable_unprepare(data->iface_clk);
+}
+
 static int ft5x06_bus_get(struct ft5x06_ts_data *data)
 {
 	int retval;
 
 	mutex_lock(&data->ft_clk_io_ctrl_mutex);
 	retval = pm_runtime_get_sync(data->client->adapter->dev.parent);
+	if (retval >= 0 &&  data->core_clk != NULL && data->iface_clk != NULL) {
+		retval = ft5x06_clk_prepare_enable(data);
+		if (retval)
+			pm_runtime_put_sync(data->client->adapter->dev.parent);
+	}
 	mutex_unlock(&data->ft_clk_io_ctrl_mutex);
 	return retval;
 }
@@ -337,6 +391,8 @@ static int ft5x06_bus_get(struct ft5x06_ts_data *data)
 static void ft5x06_bus_put(struct ft5x06_ts_data *data)
 {
 	mutex_lock(&data->ft_clk_io_ctrl_mutex);
+	if (data->core_clk != NULL && data->iface_clk != NULL)
+		ft5x06_clk_disable_unprepare(data);
 	pm_runtime_put_sync(data->client->adapter->dev.parent);
 	mutex_unlock(&data->ft_clk_io_ctrl_mutex);
 }
@@ -374,6 +430,9 @@ static ssize_t ft5x06_secure_touch_enable_store(struct device *dev,
 	if (err != 0)
 		return err;
 
+	if (!data->st_initialized)
+		return -EIO;
+
 	err = count;
 	switch (value) {
 	case 0:
@@ -394,8 +453,7 @@ static ssize_t ft5x06_secure_touch_enable_store(struct device *dev,
 		}
 		synchronize_irq(data->client->irq);
 		if (ft5x06_bus_get(data) < 0) {
-			dev_err(data->client->dev.parent,
-					"focalTech_bus_get failed\n");
+			dev_err(&data->client->dev, "ft5x06_bus_get failed\n");
 			err = -EIO;
 			break;
 		}
@@ -406,8 +464,7 @@ static ssize_t ft5x06_secure_touch_enable_store(struct device *dev,
 		break;
 
 	default:
-		dev_err(data->client->dev.parent,
-				"unsupported value: %lu\n", value);
+		dev_err(&data->client->dev, "unsupported value: %lu\n", value);
 		err = -EINVAL;
 		break;
 	}