[PATCH v6 3/3] media: ov7670: Add the ov7670_s_power function

[Wenyou Yang]

Add the ov7670_s_power function which is responsible for
manipulating the power dowm mode through the PWDN pin and the reset
operation through the RESET pin, and keep it powered at all times.

Signed-off-by: Wenyou Yang <wenyou.yang at microchip.com>
---

Changes in v6:
 - Remove .s_power callback to keep the ov7670 powered at all times.
 - Update the commit log accordingly.

Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2:
 - Add the patch to support the get_fmt ops.
 - Remove the redundant invoking ov7670_init_gpio().

 drivers/media/i2c/ov7670.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
index 73ceec63a8ca..35a30605d6e3 100644
--- a/drivers/media/i2c/ov7670.c
+++ b/drivers/media/i2c/ov7670.c
@@ -1544,6 +1544,22 @@ static int ov7670_s_register(struct v4l2_subdev *sd, const struct v4l2_dbg_regis
 }
 #endif
 
+static int ov7670_s_power(struct v4l2_subdev *sd, int on)
+{
+	struct ov7670_info *info = to_state(sd);
+
+	if (info->pwdn_gpio)
+		gpiod_direction_output(info->pwdn_gpio, !on);
+	if (on && info->resetb_gpio) {
+		gpiod_set_value(info->resetb_gpio, 1);
+		usleep_range(500, 1000);
+		gpiod_set_value(info->resetb_gpio, 0);
+		usleep_range(3000, 5000);
+	}
+
+	return 0;
+}
+
 static void ov7670_get_default_format(struct v4l2_subdev *sd,
 				      struct v4l2_mbus_framefmt *format)
 {
@@ -1694,23 +1710,25 @@ static int ov7670_probe(struct i2c_client *client,
 	if (ret)
 		return ret;
 
-	ret = ov7670_init_gpio(client, info);
-	if (ret)
-		goto clk_disable;
-
 	info->clock_speed = clk_get_rate(info->clk) / 1000000;
 	if (info->clock_speed < 10 || info->clock_speed > 48) {
 		ret = -EINVAL;
 		goto clk_disable;
 	}
 
+	ret = ov7670_init_gpio(client, info);
+	if (ret)
+		goto clk_disable;
+
+	ov7670_s_power(sd, 1);
+
 	/* Make sure it's an ov7670 */
 	ret = ov7670_detect(sd);
 	if (ret) {
 		v4l_dbg(1, debug, client,
 			"chip found @ 0x%x (%s) is not an ov7670 chip.\n",
 			client->addr << 1, client->adapter->name);
-		goto clk_disable;
+		goto power_off;
 	}
 	v4l_info(client, "chip found @ 0x%02x (%s)\n",
 			client->addr << 1, client->adapter->name);
@@ -1789,6 +1807,8 @@ static int ov7670_probe(struct i2c_client *client,
 #endif
 hdl_free:
 	v4l2_ctrl_handler_free(&info->hdl);
+power_off:
+	ov7670_s_power(sd, 0);
 clk_disable:
 	clk_disable_unprepare(info->clk);
 	return ret;
@@ -1806,6 +1826,7 @@ static int ov7670_remove(struct i2c_client *client)
 #if defined(CONFIG_MEDIA_CONTROLLER)
 	media_entity_cleanup(&info->sd.entity);
 #endif
+	ov7670_s_power(sd, 0);
 	return 0;
 }
 
-- 
2.13.0