Hi Josh,
Thanks for your patches!
On Thu, 18 Dec 2014, Josh Wu wrote:
> To support async probe for ov2640, we need remove the code to get 'mclk'
> in ov2640_probe() function. oterwise, if soc_camera host is not probed
> in the moment, then we will fail to get 'mclk' and quit the ov2640_probe()
> function.
>
> So in this patch, we move such 'mclk' getting code to ov2640_s_power()
> function. That make ov2640 survive, as we can pass a NULL (priv-clk) to
> soc_camera_set_power() function.
>
> And if soc_camera host is probed, the when ov2640_s_power() is called,
> then we can get the 'mclk' and that make us enable/disable soc_camera
> host's clock as well.
>
> Signed-off-by: Josh Wu <josh.wu@xxxxxxxxx>
> ---
> v3 -> v4:
> v2 -> v3:
> v1 -> v2:
> no changes.
>
> drivers/media/i2c/soc_camera/ov2640.c | 31 +++++++++++++++++++++----------
> 1 file changed, 21 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/media/i2c/soc_camera/ov2640.c b/drivers/media/i2c/soc_camera/ov2640.c
> index 1fdce2f..9ee910d 100644
> --- a/drivers/media/i2c/soc_camera/ov2640.c
> +++ b/drivers/media/i2c/soc_camera/ov2640.c
> @@ -739,6 +739,15 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int on)
> struct i2c_client *client = v4l2_get_subdevdata(sd);
> struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client);
> struct ov2640_priv *priv = to_ov2640(client);
> + struct v4l2_clk *clk;
> +
> + if (!priv->clk) {
> + clk = v4l2_clk_get(&client->dev, "mclk");
> + if (IS_ERR(clk))
> + dev_warn(&client->dev, "Cannot get the mclk. maybe soc-camera host is not probed yet.\n");
> + else
> + priv->clk = clk;
> + }
>
> return soc_camera_set_power(&client->dev, ssdd, priv->clk, on);
> }
> @@ -1078,21 +1087,21 @@ static int ov2640_probe(struct i2c_client *client,
> 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;
> - }
> -
> ret = ov2640_video_probe(client);
The first thing the above ov2640_video_probe() function will do is call
ov2640_s_power(), which will request the clock. So, by moving requesting
the clock from ov2640_probe() to ov2640_s_power() doesn't change how
probing will be performed, am I right? Or are there any other patched,
that change that, that I'm overseeing?
If I'm right, then I would propose an approach, already used in other
drivers instead of this one: return -EPROBE_DEFER if the clock isn't
available during probing. See ef6672ea35b5bb64ab42e18c1a1ffc717c31588a for
an example. Or did I misunderstand anything?
Thanks
Guennadi
> if (ret) {
> - v4l2_clk_put(priv->clk);
> -eclkget:
> - v4l2_ctrl_handler_free(&priv->hdl);
> + goto evideoprobe;
> } else {
> dev_info(&adapter->dev, "OV2640 Probed\n");
> }
>
> + ret = v4l2_async_register_subdev(&priv->subdev);
> + if (ret < 0)
> + goto evideoprobe;
> +
> + return 0;
> +
> +evideoprobe:
> + v4l2_ctrl_handler_free(&priv->hdl);
> return ret;
> }
>
> @@ -1100,7 +1109,9 @@ static int ov2640_remove(struct i2c_client *client)
> {
> struct ov2640_priv *priv = to_ov2640(client);
>
> - v4l2_clk_put(priv->clk);
> + v4l2_async_unregister_subdev(&priv->subdev);
> + if (priv->clk)
> + v4l2_clk_put(priv->clk);
> v4l2_device_unregister_subdev(&priv->subdev);
> v4l2_ctrl_handler_free(&priv->hdl);
> return 0;
> --
> 1.9.1
>
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