media: ov2640: add device tree support

Add device tree support for ov2640.

Cc [email protected]

Signed-off-by Josh Wu <[email protected]>

---
 drivers/media/i2c/soc_camera/ov2640.c | 95 +++++++++++++++++++++++++++++---
 1 file changed, 89 insertions(+), 6 deletions(-)

(quoted diff) +0 -0

b/drivers/media/i2c/soc_camera/ov2640.c index 9ee910d..6506126 100644

drivers/media/i2c/soc_camera/ov2640.c +7 -0

@@ -18,6 +18,8 @@
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
 #include <linux/v4l2-mediabus.h>
 #include <linux/videodev2.h>
 

@@ -283,6 +285,10 @@ struct ov2640_priv {
 	u32	cfmt_code;
 	struct v4l2_clk			*clk;
 	const struct ov2640_win_size	*win;
+
+	struct soc_camera_subdev_desc	ssdd_dt;
+	int reset_pin;
+	int pwr_down_pin;
 };
 
 /*

@@ -1047,6 +1053,70 @@ static struct v4l2_subdev_ops ov2640_subdev_ops = {
 	.video	= &ov2640_subdev_video_ops,
 };
 
+/* OF probe functions */

drivers/media/i2c/soc_camera/ov2640.c +20 -0

+
+	return 0;
+}
+
+static int ov2640_probe_dt(struct i2c_client *client,
+		struct ov2640_priv *priv)
+{
+	struct device_node *np = client->dev.of_node;
+	int ret;
+
+	priv->reset_pin = of_get_named_gpio(np, "reset-gpio", 0);
+	priv->pwr_down_pin = of_get_named_gpio(np, "power-down-gpio", 0);
+	if (!gpio_is_valid(priv->reset_pin) ||
+			!gpio_is_valid(priv->pwr_down_pin))
+		return -EINVAL;
+
+	ret = devm_gpio_request(&client->dev, priv->pwr_down_pin,
+			"power-down-pin");
+	if (ret < 0) {
+		dev_err(&client->dev, "request gpio pin %d failed\n",

drivers/media/i2c/soc_camera/ov2640.c +28 -6

+
+	/* Initialize the soc_camera_subdev_desc */
+	priv->ssdd_dt.power = ov2640_hw_power;
+	priv->ssdd_dt.reset = ov2640_hw_reset;
+	client->dev.platform_data = &priv->ssdd_dt;
+
+	return 0;
+}
+
 /*
  * i2c_driver functions
  */

@@ -1058,12 +1128,6 @@ static int ov2640_probe(struct i2c_client *client,
 	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
 	int			ret;
 
-	if (!ssdd) {
-		dev_err(&adapter->dev,
-			"OV2640: Missing platform_data for driver\n");
-		return -EINVAL;
-	}
-
 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
 		dev_err(&adapter->dev,
 			"OV2640: I2C-Adapter doesn't support SMBUS\n");

@@ -1077,6 +1141,18 @@ static int ov2640_probe(struct i2c_client *client,
 		return -ENOMEM;
 	}
 
+	if (!ssdd) {
+		if (client->dev.of_node) {
+			ret = ov2640_probe_dt(client, priv);
+			if (ret)
+				return ret;
+		} else {
+			dev_err(&client->dev,
+				"Missing platform_data for driver\n");
+			return  -EINVAL;
+		}
+	}
+
 	v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops);
 	v4l2_ctrl_handler_init(&priv->hdl, 2);
 	v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,

@@ -1123,9 +1199,16 @@ static const struct i2c_device_id ov2640_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, ov2640_id);
 
+static const struct of_device_id ov2640_of_match[] = {
+	{.compatible = "omnivision,ov2640", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ov2640_of_match);
+
 static struct i2c_driver ov2640_i2c_driver = {
 	.driver = {
 		.name = "ov2640",
+		.of_match_table = of_match_ptr(ov2640_of_match),
 	},
 	.probe    = ov2640_probe,
 	.remove   = ov2640_remove,

Hi Josh,

Thank you for the patch.

Quoted 36 lines · On Friday 28 November 2014 18:28:25 Josh Wu wrote:

Add device tree support for ov2640.

Cc devicetree at vger.kernel.org

Signed-off-by Josh Wu<[email protected]>

---
  drivers/media/i2c/soc_camera/ov2640.c | 95 +++++++++++++++++++++++++++++---
  1 file changed, 89 insertions(+), 6 deletions(-)

(quoted diff) +0 -0

b/drivers/media/i2c/soc_camera/ov2640.c index 9ee910d..6506126 100644

drivers/media/i2c/soc_camera/ov2640.c +6 -0

@@ -18,6 +18,8 @@
  #include <linux/i2c.h>
  #include <linux/slab.h>
  #include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
  #include <linux/v4l2-mediabus.h>
  #include <linux/videodev2.h>
 

@@ -283,6 +285,10 @@ struct ov2640_priv {
  	u32	cfmt_code;
  	struct v4l2_clk			*clk;
  	const struct ov2640_win_size	*win;
+
+	struct soc_camera_subdev_desc	ssdd_dt;
+	int reset_pin;
+	int pwr_down_pin;
  };
 
  /*

@@ -1047,6 +1053,70 @@ static struct v4l2_subdev_ops ov2640_subdev_ops = {
  	.video	= &ov2640_subdev_video_ops,
  };
 

drivers/media/i2c/soc_camera/ov2640.c static struct v4l2_subdev_ops ov2640_subdev_ops = { · line 1066

Quoted 11 lines

drivers/media/i2c/soc_camera/ov2640.c +11 -0

+/* OF probe functions */
+static int ov2640_hw_power(struct device *dev, int on)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ov2640_priv *priv = to_ov2640(client);
+
+	dev_dbg(&client->dev, "%s: %s the camera\n",
+			__func__, on ? "ENABLE" : "DISABLE");
+
+	/* enable or disable the camera */
+	gpio_direction_output(priv->pwr_down_pin, !on);

Isn't there a delay required to wake the chip up ?

drivers/media/i2c/soc_camera/ov2640.c static struct v4l2_subdev_ops ov2640_subdev_ops = { · line 1075

Quoted 10 lines

drivers/media/i2c/soc_camera/ov2640.c +9 -0

+
+	return 0;
+}
+
+static int ov2640_hw_reset(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ov2640_priv *priv = to_ov2640(client);
+

If the reset GPIO isn't specified you should return immediately without waiting 120ms.

drivers/media/i2c/soc_camera/ov2640.c static struct v4l2_subdev_ops ov2640_subdev_ops = { · line 1078

Quoted 4 lines

drivers/media/i2c/soc_camera/ov2640.c +3 -0

+	/* If enabled, give a reset impulse */
+	gpio_direction_output(priv->reset_pin, 0);
+	msleep(20);

Please use usleep_range().

drivers/media/i2c/soc_camera/ov2640.c static struct v4l2_subdev_ops ov2640_subdev_ops = { · line 1080

Quoted 3 lines

drivers/media/i2c/soc_camera/ov2640.c +2 -0

+	gpio_direction_output(priv->reset_pin, 1);
+	msleep(100);

Is the reset delay documented somewhere ? 100ms seems pretty large to me.

Quoted 25 lines

drivers/media/i2c/soc_camera/ov2640.c +25 -0

+
+	return 0;
+}
+
+static int ov2640_probe_dt(struct i2c_client *client,
+		struct ov2640_priv *priv)
+{
+	struct device_node *np = client->dev.of_node;
+	int ret;
+
+	priv->reset_pin = of_get_named_gpio(np, "reset-gpio", 0);
+	priv->pwr_down_pin = of_get_named_gpio(np, "power-down-gpio", 0);
+	if (!gpio_is_valid(priv->reset_pin) ||
+			!gpio_is_valid(priv->pwr_down_pin))
+		return -EINVAL;
+
+	ret = devm_gpio_request(&client->dev, priv->pwr_down_pin,
+			"power-down-pin");
+	if (ret < 0) {
+		dev_err(&client->dev, "request gpio pin %d failed\n",
+				priv->pwr_down_pin);
+		return ret;
+	}
+
+	ret = devm_gpio_request(&client->dev, priv->reset_pin, "reset_pin");

drivers/media/i2c/soc_camera/ov2640.c static struct v4l2_subdev_ops ov2640_subdev_ops = { · line 1110

Quoted 5 lines

drivers/media/i2c/soc_camera/ov2640.c +5 -0

+	if (ret < 0) {
+		dev_err(&client->dev, "request gpio pin %d failed\n",
+				priv->reset_pin);
+		return ret;
+	}

Please use the gpiod API with the devm_gpiod_get_index_optional() function, it will simply your code and take care about GPIO polarity automatically. Don't forget to specify the default state using the GPIOD_* flags.

Quoted 62 lines

drivers/media/i2c/soc_camera/ov2640.c +28 -6

+
+	/* Initialize the soc_camera_subdev_desc */
+	priv->ssdd_dt.power = ov2640_hw_power;
+	priv->ssdd_dt.reset = ov2640_hw_reset;
+	client->dev.platform_data = &priv->ssdd_dt;
+
+	return 0;
+}
+
  /*
   * i2c_driver functions
   */

@@ -1058,12 +1128,6 @@ static int ov2640_probe(struct i2c_client *client,
  	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
  	int			ret;
 
-	if (!ssdd) {
-		dev_err(&adapter->dev,
-			"OV2640: Missing platform_data for driver\n");
-		return -EINVAL;
-	}
-
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
  		dev_err(&adapter->dev,
  			"OV2640: I2C-Adapter doesn't support SMBUS\n");

@@ -1077,6 +1141,18 @@ static int ov2640_probe(struct i2c_client *client,
  		return -ENOMEM;
  	}
 
+	if (!ssdd) {
+		if (client->dev.of_node) {
+			ret = ov2640_probe_dt(client, priv);
+			if (ret)
+				return ret;
+		} else {
+			dev_err(&client->dev,
+				"Missing platform_data for driver\n");
+			return  -EINVAL;
+		}
+	}
+
  	v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops);
  	v4l2_ctrl_handler_init(&priv->hdl, 2);
  	v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,

@@ -1123,9 +1199,16 @@ static const struct i2c_device_id ov2640_id[] = {
  };
  MODULE_DEVICE_TABLE(i2c, ov2640_id);
 
+static const struct of_device_id ov2640_of_match[] = {
+	{.compatible = "omnivision,ov2640", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ov2640_of_match);
+
  static struct i2c_driver ov2640_i2c_driver = {
  	.driver = {
  		.name = "ov2640",
+		.of_match_table = of_match_ptr(ov2640_of_match),
  	},
  	.probe    = ov2640_probe,
  	.remove   = ov2640_remove,

The master clock can be optional. It's a common clock framework clock. It can make sensor output a pixel clock to the camera interface.

If you just use a external oscillator clock as the master clock, then, just don't need set 'mck' in dt node.

Signed-off-by Josh Wu <[email protected]>

---
 drivers/media/i2c/soc_camera/ov2640.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(quoted diff) +0 -0

b/drivers/media/i2c/soc_camera/ov2640.c index 6506126..06c2aa9 100644

drivers/media/i2c/soc_camera/ov2640.c +5 -0

@@ -13,6 +13,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/clk.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/i2c.h>

@@ -31,6 +32,8 @@
 
 #define VAL_SET(x, mask, rshift, lshift)  \
 		((((x) >> rshift) & mask) << lshift)
+#define DEFAULT_MASTER_CLK_FREQ		25000000
+
 /*
  * DSP registers
  * register offset for BANK_SEL == BANK_SEL_DSP

@@ -284,6 +287,7 @@ struct ov2640_priv {
 	struct v4l2_ctrl_handler	hdl;
 	u32	cfmt_code;
 	struct v4l2_clk			*clk;
+	struct clk			*master_clk;
 	const struct ov2640_win_size	*win;
 
 	struct soc_camera_subdev_desc	ssdd_dt;

@@ -746,6 +750,7 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int
 on) struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client);
 struct ov2640_priv *priv = to_ov2640(client);
 	struct v4l2_clk *clk;
+	int ret = 0;
 
 	if (!priv->clk) {
 		clk = v4l2_clk_get(&client->dev, "mclk");

drivers/media/i2c/soc_camera/ov2640.c +4 -0

+		if (ret < 0)
+			return ret;
+	}
+
 	v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops);
 	v4l2_ctrl_handler_init(&priv->hdl, 2);
 	v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,

Hi Josh,

(CC'ing the devicetree at vger.kernel.org mailing list)

Thank you for the patch.

Quoted 46 lines · On Friday 28 November 2014 18:28:26 Josh Wu wrote:

The master clock can be optional. It's a common clock framework clock. It can make sensor output a pixel clock to the camera interface.

If you just use a external oscillator clock as the master clock, then, just don't need set 'mck' in dt node.

Signed-off-by Josh Wu <[email protected]>

---
  drivers/media/i2c/soc_camera/ov2640.c | 25 +++++++++++++++++++++++++
  1 file changed, 25 insertions(+)

(quoted diff) +0 -0

b/drivers/media/i2c/soc_camera/ov2640.c index 6506126..06c2aa9 100644

drivers/media/i2c/soc_camera/ov2640.c +5 -0

@@ -13,6 +13,7 @@
   * published by the Free Software Foundation.
   */
 
+#include <linux/clk.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/i2c.h>

@@ -31,6 +32,8 @@
 
  #define VAL_SET(x, mask, rshift, lshift)  \
  		((((x) >> rshift) & mask) << lshift)
+#define DEFAULT_MASTER_CLK_FREQ		25000000
+
  /*
   * DSP registers
   * register offset for BANK_SEL == BANK_SEL_DSP

@@ -284,6 +287,7 @@ struct ov2640_priv {
  	struct v4l2_ctrl_handler	hdl;
  	u32	cfmt_code;
  	struct v4l2_clk			*clk;
+	struct clk			*master_clk;
  	const struct ov2640_win_size	*win;
 
  	struct soc_camera_subdev_desc	ssdd_dt;

@@ -746,6 +750,7 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int
 on) struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client);
 struct ov2640_priv *priv = to_ov2640(client);
  	struct v4l2_clk *clk;
+	int ret = 0;
 

drivers/media/i2c/soc_camera/ov2640.c static int ov2640_s_power(struct v4l2_subdev *sd, int · line 763

Quoted 7 lines

drivers/media/i2c/soc_camera/ov2640.c +1 -0

  	if (!priv->clk) {
  		clk = v4l2_clk_get(&client->dev, "mclk");

@@ -755,6 +760,16 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int
 on) priv->clk = clk;
  	}
 
+	if (!IS_ERR(priv->master_clk)) {

The clock should be mandatory, you can thus drop this check.

drivers/media/i2c/soc_camera/ov2640.c static int ov2640_s_power(struct v4l2_subdev *sd, int on) · line 770

Quoted 8 lines

drivers/media/i2c/soc_camera/ov2640.c +7 -0

+		if (on)
+			ret = clk_prepare_enable(priv->master_clk);
+		else
+			clk_disable_unprepare(priv->master_clk);
+
+		if (ret)
+			return ret;

You can move the error check inside the first branch of the if and remove the ret = 0 initialization above.

drivers/media/i2c/soc_camera/ov2640.c static int ov2640_s_power(struct v4l2_subdev *sd, int on) · line 773

Quoted 3 lines

drivers/media/i2c/soc_camera/ov2640.c +2 -0

+	}
+
  	return soc_camera_set_power(&client->dev, ssdd, priv->clk, on);

If this call fails you should disable or enable the clock to undo the enable/disable above.

Quoted 7 lines

drivers/media/i2c/soc_camera/ov2640.c +0 -0

  }
 

@@ -1153,6 +1168,16 @@ static int ov2640_probe(struct i2c_client *client,
  		}
  	}
 

drivers/media/i2c/soc_camera/ov2640.c static int ov2640_probe(struct i2c_client *client, · line 1176

Quoted 6 lines

drivers/media/i2c/soc_camera/ov2640.c +6 -0

+	priv->master_clk = devm_clk_get(&client->dev, "mck");
+	if (!IS_ERR(priv->master_clk)) {
+		/* Set ISI_MCK's frequency, it should be faster than pixel
+		 * clock.
+		 */
+		ret = clk_set_rate(priv->master_clk, DEFAULT_MASTER_CLK_FREQ);

The clock frequency should be system-dependent. For the DT case an easy implementation would be to use the assigned-clock-rates to set the desired clock frequency is case of a variable clock, as adding a sensor-specific property to specify the desired clock frequency only to read that property in the driver and call clk_set_rate() seems a bit pointless to me.

Quoted 8 lines

drivers/media/i2c/soc_camera/ov2640.c +4 -0

+		if (ret < 0)
+			return ret;
+	}
+
  	v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops);
  	v4l2_ctrl_handler_init(&priv->hdl, 2);
  	v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,

Add the document for ov2640 dt.

Cc [email protected]

Signed-off-by Josh Wu <[email protected]>

---
 .../devicetree/bindings/media/i2c/ov2640.txt       | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ov2640.txt

(quoted diff) +0 -0

b/Documentation/devicetree/bindings/media/i2c/ov2640.txt new file mode 100644
index 0000000..adec147

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +2 -0

+Optional Properties:
+- clocks          : reference master clock, if using external fixed clock,

you
+ no need to have such property.

+- clock-names : Must be "mck", it means the master clock for ov2640.

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +2 -0

+
+For further reading of port node refer

Documentation/devicetree/bindings/media/
+video-interfaces.txt.

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +11 -0

+			clocks = <&pck1>;
+			clock-names = "mck";
+
+			port {
+				ov2640_0: endpoint {
+					remote-endpoint = <&isi_0>;
+					bus-width = <8>;
+				};
+			};
+		};
+	};

Hi Josh,

Thank you for the patch.

Quoted 16 lines · On Friday 28 November 2014 18:28:27 Josh Wu wrote:

Add the document for ov2640 dt.

Cc devicetree at vger.kernel.org

Signed-off-by Josh Wu <[email protected]>

---
  .../devicetree/bindings/media/i2c/ov2640.txt       | 43 +++++++++++++++++++
  1 file changed, 43 insertions(+)

create mode 100644 Documentation/devicetree/bindings/media/i2c/ov2640.txt

(quoted diff) +0 -0

b/Documentation/devicetree/bindings/media/i2c/ov2640.txt new file mode 100644
index 0000000..adec147

Documentation/devicetree/bindings/media/i2c/ov2640.txt line 8

Quoted 8 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +8 -0

@@ -0,0 +1,43 @@
+* Omnivision ov2640 CMOS sensor
+
+The Omnivision OV2640 sensor support multiple resolutions output, such as
+CIF, SVGA, UXGA. It also can support YUV422/420, RGB565/555 or raw RGB
+output format.
+
+Required Properties :
+- compatible      : Must be "omnivision,ov2640"

The usual practice is to use the company's stock ticker as a prefix. In this case the compatible string would be "ovti,ov2640". You need to add the prefix to Documentation/devicetree/bindings/vendor-prefixes.txt.

Documentation/devicetree/bindings/media/i2c/ov2640.txt line 10

Quoted 2 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +2 -0

+- reset-gpio      : reset pin
+- power-down-gpio : power down pin

That should be reset-gpios and power-down-gpios, even if there's a single GPIO. Furthermore, given that the power down pin is named PWDN you might want to name the property pwdn-gpios.

The reset and pwdn signals won't be connected on all boards, so the two properties should be optional.

Quoted 4 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +2 -0

+Optional Properties:
+- clocks          : reference master clock, if using external fixed clock,

you
+ no need to have such property.

The clock is required by the chip, so even when using an external fixed clock the property should be present, and reference a fixed clock node. The clocks and clock-names properties should thus be mandatory.

Quoted 1 line

+- clock-names : Must be "mck", it means the master clock for ov2640.

The clock input is named xvclk in the datasheet, you should use the same name here.

Quoted 4 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +2 -0

+
+For further reading of port node refer

Documentation/devicetree/bindings/media/
+video-interfaces.txt.

Even if you reference that document you should still mention what port node(s) these bindings require. Something like the following text should be enough.

"The device node must contain one 'port' child node for its digital output video port, in accordance with the video interface bindings defined in Documentation/devicetree/bindings/media/video-interfaces.txt."

Documentation/devicetree/bindings/media/i2c/ov2640.txt line 27

Quoted 9 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +9 -0

+
+Example:
+
+	i2c1: i2c at f0018000 {
+		ov2640: camera at 0x30 {
+			compatible = "omnivision,ov2640";
+			reg = <0x30>;
+
+			... ...

No need for an ellipsis, what are you trying to hide ? :-)

Documentation/devicetree/bindings/media/i2c/ov2640.txt line 32

Quoted 6 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +5 -0

+
+			reset-gpio = <&pioE 24 GPIO_ACTIVE_HIGH>;
+			power-down-gpio = <&pioE 29 GPIO_ACTIVE_HIGH>;
+
+			/* use pck1 for the master clock of ov2640 */

I think you can drop the comment.

Quoted 12 lines

Documentation/devicetree/bindings/media/i2c/ov2640.txt new file +11 -0

+			clocks = <&pck1>;
+			clock-names = "mck";
+
+			port {
+				ov2640_0: endpoint {
+					remote-endpoint = <&isi_0>;
+					bus-width = <8>;
+				};
+			};
+		};
+	};