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SubjectRe: [PATCH] media: i2c: OV5647: gate clock lane before stream on
Hi all,

2017-07-25 10:34 GMT+08:00 Jacob Chen <jacob-chen@iotwrt.com>:
> According to datasheet, BIT5 in reg-0x4800 are used to
> enable/disable clock lane gate.
>
> It's wrong to make clock lane free running before
> sensor stream on was called, while the mipi phy
> are not initialized.
>
> Signed-off-by: Jacob Chen <jacob-chen@iotwrt.com>
> ---
> drivers/media/i2c/ov5647.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
> index 95ce90f..d3e6fd0 100644
> --- a/drivers/media/i2c/ov5647.c
> +++ b/drivers/media/i2c/ov5647.c
> @@ -253,6 +253,10 @@ static int ov5647_stream_on(struct v4l2_subdev *sd)
> {
> int ret;
>
> + ret = ov5647_write(sd, 0x4800, 0x04);
> + if (ret < 0)
> + return ret;
> +
> ret = ov5647_write(sd, 0x4202, 0x00);
> if (ret < 0)
> return ret;
> @@ -264,6 +268,10 @@ static int ov5647_stream_off(struct v4l2_subdev *sd)
> {
> int ret;
>
> + ret = ov5647_write(sd, 0x4800, 0x25);
> + if (ret < 0)
> + return ret;
> +
> ret = ov5647_write(sd, 0x4202, 0x0f);
> if (ret < 0)
> return ret;
> @@ -320,7 +328,7 @@ static int __sensor_init(struct v4l2_subdev *sd)
> return ret;
> }
>
> - return ov5647_write(sd, 0x4800, 0x04);
> + return ov5647_stream_off(sd);
> }
>
> static int ov5647_sensor_power(struct v4l2_subdev *sd, int on)
> --
> 2.7.4
>

Can anyone comment on it?

I saw there is a same discussion in https://patchwork.kernel.org/patch/9569031/
There is a comment in i.MX CSI2 driver.
"
Configure MIPI Camera Sensor to put all Tx lanes in LP-11 state.
This must be carried out by the MIPI sensor's s_power(ON) subdev
op.
"
That's what this patch do, sensor driver should make sure that clock
lanes are in stop state while not streaming.

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