| Message ID | 20200415105004.2497356-1-jacopo+renesas@jmondi.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | v4l2-subdev: Introduce get_mbus_format pad op | expand |
Hi Jacopo, Thank you for the patches. On Wed, Apr 15, 2020 at 12:49:57PM +0200, Jacopo Mondi wrote: > v2 introduces two new patches that could be likely squashed in later to > deprecate the g_mbus_config() operation in documentation and expand the newly > introduced function documentation by popular demand. > > Will report again the use cases I'm trying to address here: > ------------------------------------------------------------------------------ > Quoting: > https://patchwork.kernel.org/cover/10855919/ > "The use case this series cover is the following one: > the Gen-3 R-Car boards include an ADV748x HDMI/CVBS to CSI-2 converter > connected to its CSI-2 receivers. The ADV748x chip has recently gained support > for routing both HDMI and analogue video streams through its 4 lanes TXA > transmitter, specifically to support the Ebisu board that has a single CSI-2 > receiver, compared to all other Gen-3 board where the ADV748x TXes are connected > to different CSI-2 receivers, and where analogue video is streamed out from the > ADV748x single lane TXB transmitter. > To properly support transmission of analogue video through TXA, the number of > data lanes shall be dynamically reduced to 1, in order to comply with the MIPI > CSI-2 minimum clock frequency requirements" > > During the discussion of the RFC, Dave reported another use case for media > bus parameter negotiation on his platform: > https://patchwork.kernel.org/patch/10855923/#22569149 > > Another possible use case is for parallel bus multiplexing, where multiple image > sensor share the parallel bus lines and they get activated alternatively through > an enable signal. While this might not be most clever design, it's often seen > in the wild, and this operation allow receivers to re-configure their bus > parameter in between streaming session. Isn't this already supported today, with the bus configuration for each source specified in the corresponding endpoint (on the receiver side) in DT ? > Hyun is now using this series to configure GMSL devices. > ------------------------------------------------------------------------------ > > v1->v2: > - Address Sakari's comment to use unsigned int in place of bools > - Add two new patches to address documentation > - Adjust rcar-csi2 patch as much as possible according to Niklas comments > - Add Niklas's tags > > Jacopo Mondi (6): > media: v4l2-subdv: Introduce get_mbus_config pad op > media: v4l2-subdev: Deprecate g_mbus_config video op > media: v4l2-subdev: Expand get_mbus_config doc > media: i2c: adv748x: Adjust TXA data lanes number > media: i2c: adv748x: Implement get_mbus_config > media: rcar-csi2: Negotiate data lanes number > > drivers/media/i2c/adv748x/adv748x-core.c | 31 ++++++-- > drivers/media/i2c/adv748x/adv748x-csi2.c | 15 ++++ > drivers/media/i2c/adv748x/adv748x.h | 1 + > drivers/media/platform/rcar-vin/rcar-csi2.c | 53 ++++++++++++- > include/media/v4l2-subdev.h | 82 ++++++++++++++++++++- > 5 files changed, 171 insertions(+), 11 deletions(-) >
Hi Laurent, On Mon, Apr 20, 2020 at 05:02:28AM +0300, Laurent Pinchart wrote: > Hi Jacopo, > > Thank you for the patches. > > On Wed, Apr 15, 2020 at 12:49:57PM +0200, Jacopo Mondi wrote: > > v2 introduces two new patches that could be likely squashed in later to > > deprecate the g_mbus_config() operation in documentation and expand the newly > > introduced function documentation by popular demand. > > > > Will report again the use cases I'm trying to address here: > > ------------------------------------------------------------------------------ > > Quoting: > > https://patchwork.kernel.org/cover/10855919/ > > "The use case this series cover is the following one: > > the Gen-3 R-Car boards include an ADV748x HDMI/CVBS to CSI-2 converter > > connected to its CSI-2 receivers. The ADV748x chip has recently gained support > > for routing both HDMI and analogue video streams through its 4 lanes TXA > > transmitter, specifically to support the Ebisu board that has a single CSI-2 > > receiver, compared to all other Gen-3 board where the ADV748x TXes are connected > > to different CSI-2 receivers, and where analogue video is streamed out from the > > ADV748x single lane TXB transmitter. > > To properly support transmission of analogue video through TXA, the number of > > data lanes shall be dynamically reduced to 1, in order to comply with the MIPI > > CSI-2 minimum clock frequency requirements" > > > > During the discussion of the RFC, Dave reported another use case for media > > bus parameter negotiation on his platform: > > https://patchwork.kernel.org/patch/10855923/#22569149 > > > > Another possible use case is for parallel bus multiplexing, where multiple image > > sensor share the parallel bus lines and they get activated alternatively through > > an enable signal. While this might not be most clever design, it's often seen > > in the wild, and this operation allow receivers to re-configure their bus > > parameter in between streaming session. > > Isn't this already supported today, with the bus configuration for each > source specified in the corresponding endpoint (on the receiver side) in > DT ? > I think you're right.. One should probably cache each endpoint configuration parsed at probe time.. I was thinking at multiple connections to the same endpoint, but seems it's not possible.. good, I'll drop this > > Hyun is now using this series to configure GMSL devices. > > ------------------------------------------------------------------------------ > > > > v1->v2: > > - Address Sakari's comment to use unsigned int in place of bools > > - Add two new patches to address documentation > > - Adjust rcar-csi2 patch as much as possible according to Niklas comments > > - Add Niklas's tags > > > > Jacopo Mondi (6): > > media: v4l2-subdv: Introduce get_mbus_config pad op > > media: v4l2-subdev: Deprecate g_mbus_config video op > > media: v4l2-subdev: Expand get_mbus_config doc > > media: i2c: adv748x: Adjust TXA data lanes number > > media: i2c: adv748x: Implement get_mbus_config > > media: rcar-csi2: Negotiate data lanes number > > > > drivers/media/i2c/adv748x/adv748x-core.c | 31 ++++++-- > > drivers/media/i2c/adv748x/adv748x-csi2.c | 15 ++++ > > drivers/media/i2c/adv748x/adv748x.h | 1 + > > drivers/media/platform/rcar-vin/rcar-csi2.c | 53 ++++++++++++- > > include/media/v4l2-subdev.h | 82 ++++++++++++++++++++- > > 5 files changed, 171 insertions(+), 11 deletions(-) > > > > -- > Regards, > > Laurent Pinchart