Hi, Guennadi
Thanks for the review.
On 12/19/2014 5:59 AM, Guennadi Liakhovetski wrote:
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?
yes, you are right. In this patch, the "mclk" will requested by
ov2640_s_power().
The reason why I put the getting "mclk" code from ov2640_probe() to
ov2640_s_power() is : as the "mclk" here is camera host's peripheral
clock. That means ov2640 still can be probed properly (read ov2640 id)
even no "mclk". So when I move this code to ov2640_s_power(), otherwise
the ov2640_probe() will be failed or DEFER_PROBE.
Is this true for all camera host? If it's not true, then I think use
-EPROBE_DEFER would be a proper way.
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?
Actually months ago I already done a version of ov2640 patch which use
-EPROBE_DEFER way.
But now I think the ov2640 can be probed correctly without "mclk", so it
is no need to return -EPROBE_DEFER.
And the v4l2 asyn API can handle the synchronization of host. So I
prefer to use this way.
What do you think about this?
Best Regards,
Josh Wu
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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