[media] mt9t001: Add clock support

The sensor needs a master clock, handle it explictly in the driver.

Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/i2c/mt9t001.c

···
  * published by the Free Software Foundation.
  */
 
+#include <linux/clk.h>
 #include <linux/i2c.h>
 #include <linux/log2.h>
 #include <linux/module.h>
···
 	struct v4l2_subdev subdev;
 	struct media_pad pad;
 
+	struct clk *clk;
 	struct regulator_bulk_data regulators[2];
 
 	struct mutex power_lock; /* lock to protect power_count */
···
 
 static int mt9t001_power_on(struct mt9t001 *mt9t001)
 {
+	int ret;
+
 	/* Bring up the supplies */
-	return regulator_bulk_enable(ARRAY_SIZE(mt9t001->regulators),
-				     mt9t001->regulators);
+	ret = regulator_bulk_enable(ARRAY_SIZE(mt9t001->regulators),
+				   mt9t001->regulators);
+	if (ret < 0)
+		return ret;
+
+	/* Enable clock */
+	ret = clk_prepare_enable(mt9t001->clk);
+	if (ret < 0)
+		regulator_bulk_disable(ARRAY_SIZE(mt9t001->regulators),
+				       mt9t001->regulators);
+
+	return ret;
 }
 
 static void mt9t001_power_off(struct mt9t001 *mt9t001)
 {
 	regulator_bulk_disable(ARRAY_SIZE(mt9t001->regulators),
 			       mt9t001->regulators);
+
+	clk_disable_unprepare(mt9t001->clk);
+}
 
 static int __mt9t001_set_power(struct mt9t001 *mt9t001, bool on)
 {
···
 	if (ret < 0) {
 		dev_err(&client->dev, "Unable to get regulators\n");
 		return ret;
+	}
+
+	mt9t001->clk = devm_clk_get(&client->dev, NULL);
+	if (IS_ERR(mt9t001->clk)) {
+		dev_err(&client->dev, "Unable to get clock\n");
+		return PTR_ERR(mt9t001->clk);
 	}
 
 	v4l2_ctrl_handler_init(&mt9t001->ctrls, ARRAY_SIZE(mt9t001_ctrls) +