linux-kernel - Re: [PATCH v3 1/2] media: i2c: OV5647: ensure clock lane in LP-11 state before streaming on

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Date:   Mon, 16 Oct 2017 17:49:59 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Luis Oliveira <Luis.Oliveira@...opsys.com>
Cc:     Jacob Chen <jacob-chen@...wrt.com>, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, mchehab@...nel.org,
        vladimir_zapolskiy@...tor.com, hans.verkuil@...co.com,
        sakari.ailus@...ux.intel.com, p.zabel@...gutronix.de,
        Joao Pinto <Joao.Pinto@...opsys.com>
Subject: Re: [PATCH v3 1/2] media: i2c: OV5647: ensure clock lane in LP-11
 state before streaming on

On Mon, Oct 16, 2017 at 03:19:09PM +0100, Luis Oliveira wrote:
> Hi all,
> 
> Sorry for the delay and thank you for the fix.
> I just checked the databook and the changes makes sense.
> 
> cheers,
> Luis
> 
> On 16-Oct-17 13:23, Sakari Ailus wrote:
> > Luis,
> > 
> > Any comment on these?
> > 
> > On Sun, Oct 01, 2017 at 06:22:37PM +0800, Jacob Chen wrote:
> >> When I was supporting Rpi Camera Module on the ASUS Tinker board,
> >> I found this driver have some issues with rockchip's mipi-csi driver.
> >> It didn't place clock lane in LP-11 state before performing
> >> D-PHY initialisation.
> >>
> >> From our experience, on some OV sensors,
> >> LP-11 state is not achieved while BIT(5)-0x4800 is cleared.
> >>
> >> So let's set BIT(5) and BIT(0) both while not streaming, in order to
> >> coax the clock lane into LP-11 state.
> >>
> >> 0x4800 : MIPI CTRL 00
> >> 	BIT(5) : clock lane gate enable
> >> 		0: continuous
> >> 		1: none-continuous
> >> 	BIT(0) : manually set clock lane
> >> 		0: Not used
> >> 		1: used
> >>
> >> Signed-off-by: Jacob Chen <jacob-chen@...wrt.com>
> >> ---
> >>  drivers/media/i2c/ov5647.c | 13 ++++++++++++-
> >>  1 file changed, 12 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
> >> index 95ce90fdb876..247302d01f53 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 +328,10 @@ static int __sensor_init(struct v4l2_subdev *sd)
> >>  			return ret;
> >>  	}
> >>  
> >> -	return ov5647_write(sd, 0x4800, 0x04);
> >> +	/*
> >> +	 * stream off to make the clock lane into LP-11 state.
> >> +	 */
> >> +	return ov5647_stream_off(sd);
> >>  }
> >>  
> >>  static int ov5647_sensor_power(struct v4l2_subdev *sd, int on)
> >> -- 
> >> 2.14.1
> >>
> > 
> Reviewed-by: Luis Oliveira <lolivei@...opsys.com>

Thanks. I'll apply the patches then.

-- 
Sakari Ailus
e-mail: sakari.ailus@....fi