[v2,media] ov2640: add support for async device registration

  Since the the v4l2_clk_get() may return a EPROBE_DEFER during async
probing. So move the v4l2_clk_get() to the beginning of the
probe(). Only when we get mclk successfully we continue the probe.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
---
v1 -> v2:
  just return PTR_ERR(clk) as it can be -EPROBE_DEFER.
  refined the commit message

 drivers/media/i2c/soc_camera/ov2640.c |   43 +++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 15 deletions(-)
  

Hi, all

since v4l2_clk_get() WON'T return EPROBE_DEFER. So this version of patch 
is invalid.
Please drop this version of the patch.
Sorry for the noise.

Best Regards,
Josh Wu

On 3/20/2014 5:01 PM, Josh Wu wrote:
> Since the the v4l2_clk_get() may return a EPROBE_DEFER during async
> probing. So move the v4l2_clk_get() to the beginning of the
> probe(). Only when we get mclk successfully we continue the probe.
>
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> ---
> v1 -> v2:
>    just return PTR_ERR(clk) as it can be -EPROBE_DEFER.
>    refined the commit message
>
>   drivers/media/i2c/soc_camera/ov2640.c |   43 +++++++++++++++++++++------------
>   1 file changed, 28 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/media/i2c/soc_camera/ov2640.c b/drivers/media/i2c/soc_camera/ov2640.c
> index 6c6b1c3..7c77a15 100644
> --- a/drivers/media/i2c/soc_camera/ov2640.c
> +++ b/drivers/media/i2c/soc_camera/ov2640.c
> @@ -22,6 +22,7 @@
>   #include <linux/videodev2.h>
>   
>   #include <media/soc_camera.h>
> +#include <media/v4l2-async.h>
>   #include <media/v4l2-clk.h>
>   #include <media/v4l2-subdev.h>
>   #include <media/v4l2-ctrls.h>
> @@ -1069,6 +1070,7 @@ static int ov2640_probe(struct i2c_client *client,
>   	struct ov2640_priv	*priv;
>   	struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client);
>   	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
> +	struct v4l2_clk		*clk;
>   	int			ret;
>   
>   	if (!ssdd) {
> @@ -1083,13 +1085,20 @@ static int ov2640_probe(struct i2c_client *client,
>   		return -EIO;
>   	}
>   
> +	clk = v4l2_clk_get(&client->dev, "mclk");
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
>   	priv = devm_kzalloc(&client->dev, sizeof(struct ov2640_priv), GFP_KERNEL);
>   	if (!priv) {
>   		dev_err(&adapter->dev,
>   			"Failed to allocate memory for private data!\n");
> -		return -ENOMEM;
> +		ret = -ENOMEM;
> +		goto err_kzalloc;
>   	}
>   
> +	priv->clk = clk;
> +
>   	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,
> @@ -1097,23 +1106,26 @@ static int ov2640_probe(struct i2c_client *client,
>   	v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,
>   			V4L2_CID_HFLIP, 0, 1, 1, 0);
>   	priv->subdev.ctrl_handler = &priv->hdl;
> -	if (priv->hdl.error)
> -		return priv->hdl.error;
> -
> -	priv->clk = v4l2_clk_get(&client->dev, "mclk");
> -	if (IS_ERR(priv->clk)) {
> -		ret = PTR_ERR(priv->clk);
> -		goto eclkget;
> +	if (priv->hdl.error) {
> +		ret = priv->hdl.error;
> +		goto err_kzalloc;
>   	}
>   
>   	ret = ov2640_video_probe(client);
> -	if (ret) {
> -		v4l2_clk_put(priv->clk);
> -eclkget:
> -		v4l2_ctrl_handler_free(&priv->hdl);
> -	} else {
> -		dev_info(&adapter->dev, "OV2640 Probed\n");
> -	}
> +	if (ret)
> +		goto err_probe;
> +
> +	ret = v4l2_async_register_subdev(&priv->subdev);
> +	if (ret)
> +		goto err_probe;
> +
> +	dev_info(&adapter->dev, "OV2640 Probed\n");
> +	return 0;
> +
> +err_probe:
> +	v4l2_ctrl_handler_free(&priv->hdl);
> +err_kzalloc:
> +	v4l2_clk_put(clk);
>   
>   	return ret;
>   }
> @@ -1122,6 +1134,7 @@ static int ov2640_remove(struct i2c_client *client)
>   {
>   	struct ov2640_priv       *priv = to_ov2640(client);
>   
> +	v4l2_async_unregister_subdev(&priv->subdev);
>   	v4l2_clk_put(priv->clk);
>   	v4l2_device_unregister_subdev(&priv->subdev);
>   	v4l2_ctrl_handler_free(&priv->hdl);

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