> -----Original Message----- > From: Jacopo Mondi <jacopo@xxxxxxxxxx> > Sent: 19 December 2022 08:14 PM > To: shravan Chippa - I35088 <Shravan.Chippa@xxxxxxxxxxxxx> > Cc: paul.j.murphy@xxxxxxxxx; daniele.alessandrelli@xxxxxxxxx; > mchehab@xxxxxxxxxx; linux-media@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v7 1/5] media: i2c: imx334: modify link frequency as for > the configureation > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the > content is safe > > Hi Shravan > > On Mon, Dec 19, 2022 at 11:45:22AM +0530, shravan kumar wrote: > > From: Shravan Chippa <shravan.chippa@xxxxxxxxxxxxx> > > > > Currently imx334 sensor driver is configured for 1782Mbps/lane for > > 3840x2160@60 resolution with reqired reg mode values but if we run the > > command "v4l2-ctl --all -d /dev/v4l-subdevX" it is showing incorrect > > link frequeny, This is because of the incorrect value of > > IMX334_LINK_FREQ witch is 891000000. it should be 1782000000. > > > > In general with the value of 891000000 link frequency it is not > > possible to configure 3840x2160@60 resolution. > > > > Fixes: 9746b11715c3 ("media: i2c: Add imx334 camera sensor driver") > > > > Signed-off-by: Shravan Chippa <shravan.chippa@xxxxxxxxxxxxx> > > --- > > drivers/media/i2c/imx334.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/imx334.c b/drivers/media/i2c/imx334.c > > index 7b0a9086447d..acc9f9f15e47 100644 > > --- a/drivers/media/i2c/imx334.c > > +++ b/drivers/media/i2c/imx334.c > > @@ -49,7 +49,7 @@ > > #define IMX334_INCLK_RATE 24000000 > > > > /* CSI2 HW configuration */ > > -#define IMX334_LINK_FREQ 891000000 > > +#define IMX334_LINK_FREQ 1782000000 > > Is this your reasoning ? > > width: 3840 > hblank: 560 > height: 2160 > vblank: 2340 > bpp: 12 > fps: 60 > lanes: 4 > > Total bandwidth: (3840 + 560) * (2160 + 2340) * 60 * 12 = 14.256.000.000 > Bandwidth per lane = Total / 4 = 3.564.000.000 mipi clock = > Bandwidth_per_lane / 2 = 1.782.000.000 > > Two questions: > > - Should you update the pixel clock as well ? It is currently set to > 594000000 while as per the above reasoning it should be doubled too. > > - Where is the sensor's clock tree programmed in the driver ? > It's kind of weird that the pixel_clock and link_freq in the driver > are half of what they theoretically should be... > > As per my understanding. the mode_3840x2160_regs[] array value which is written through the i2c bus is 4k resolution, 60fps, link frequency 1782Mbps per lane but the vblank value is dynamic from user space. Min-90 to Max-130000, default value is 2340. With the default value, we will get 30fps. if we set vblank value from user space it will change FPS. Total bandwidth: (3840 + 560) * (2160 + 2340) * 30 * 12 = 7.128.000.000 Bandwidth per lane = Total / 4 = 1.782.000.000 Thanks, Shravan > > > #define IMX334_NUM_DATA_LANES 4 > > > > #define IMX334_REG_MIN 0x00 > > -- > > 2.34.1 > >