[PATCH v4 2/5] media: ov2640: add async probe function

[Josh Wu]

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...@atmel.com>
---
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);
        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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