| Message ID | 20221219061526.3169369-1-shravan.chippa@microchip.com |
|---|---|
| Headers | show |
| Series | media: i2c: imx334: support lower bandwidth mode | expand |
Hi Shravan On Tue, Dec 20, 2022 at 11:11:15AM +0000, Shravan.Chippa@microchip.com wrote: > > > > -----Original Message----- > > From: Jacopo Mondi <jacopo@jmondi.org> > > Sent: 19 December 2022 08:14 PM > > To: shravan Chippa - I35088 <Shravan.Chippa@microchip.com> > > Cc: paul.j.murphy@intel.com; daniele.alessandrelli@intel.com; > > mchehab@kernel.org; linux-media@vger.kernel.org; linux- > > kernel@vger.kernel.org > > 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@microchip.com> > > > > > > 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@microchip.com> > > > --- > > > 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. Ah, it's 30, not 60. So my calculations above should be halved > > if we set vblank value from user space it will change FPS. > Sure, but the link frequency stays the same, and it should be computed with the FPS resulting from the current blankings > Total bandwidth: (3840 + 560) * (2160 + 2340) * 30 * 12 = 7.128.000.000 Correct > Bandwidth per lane = Total / 4 = 1.782.000.000 Correct. But with CID_LINK_FREQ you're reporting the bus link frequency, not the lane bandwidth. As MIPI CSI-2 uses DDR read mode, two bits per clock cycle are transmitted, hence the bus frequency is half of the lane bandwidth. TL;DR you don't need this patch, the current value is correct as it is in my understanding. Thanks j > > Thanks, > Shravan > > > > > > #define IMX334_NUM_DATA_LANES 4 > > > > > > #define IMX334_REG_MIN 0x00 > > > -- > > > 2.34.1 > > >
From: Shravan Chippa <shravan.chippa@microchip.com> Hi This patch series is for imx334 sensor driver support for lower bandwidth Some platforms may not be capable of supporting the bandwidth required for 12 bit or 3840x2160@60 resolutions. Add support for dynamically selecting 10 bit and 1920x1080@30 resolutions while leaving the existing configuration as default V6 -> V7 Reloved: kernel test robot warning "drivers/media/i2c/imx334.c:767:15: warning: unused variable 'i' " V5 -> V6 -Drop the dt-binding patch -Optimize the code to avoid duplicating the lines -Added proper mutex while imx334_mbus_codes array -Modified Function __v4l2_ctrl_modify_range arguments as per the review commants -Added hblank dummy set ctrl -Removed Redundant comment -corrected code alignment -All commit msgs are re-written V4 -> V5 -Added 5 more patchs as per the review comments witch has below updates -Updated 1782000000Mbps link frequency for 3840x2160@60 as per the mode values -Updated 1782000000Mbps link frequency in dt-bindings also -Updated 3840x2160@60 mode array with default(reset) values -Updated hblank __v4l2_ctrl_s_ctrl() to __v4l2_ctrl_modify_range() Suggested-by: Jacopo Mondi <jacopo@jmondi.org> -Current mode update only when we try to set V4L2_SUBDEV_FORMAT_ACTIVE -Added link frequency (891000000Mbps) and pixel rate (74250000) to 1920x1080@30 mode Suggested-by: Sakari Ailus <sakari.ailus@iki.fi> -Updated commit message V3 -> V4 - Make the 12 bit and 3840x2160 as default - Set bus code SRGGB12 if set format fails V2 -> V3 - Fixed the warning reported by kernel test robot V1 -> V2 - Addressed the review comment given by Jacopo Mondi, Which has bug in imx334_enum_frame_size() loop function, - Renamed array codes[] to imx334_mbus_codes[] Shravan Chippa (5): media: i2c: imx334: modify link frequency as for the configureation media: i2c: imx334: replace __v4l2_ctrl_s_ctrl to __v4l2_ctrl_modify_range media: i2c: imx334: add missing reset values for mode 3840x2160_regs[] media: i2c: imx334: support lower bandwidth mode media: i2c: imx334: update pixel and link frequency drivers/media/i2c/imx334.c | 337 ++++++++++++++++++++++++++++++++++--- 1 file changed, 309 insertions(+), 28 deletions(-)