[v2,0/5] drm/bridge: samsung-dsim: fix various modes with ADV7535 bridge

  I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter,
which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few
modes were working, but in many modes my monitor stayed dark.

This series fixes the Samsung DSIM bridge driver to bring up a few more
modes:

The driver read the rate of the PLL ref clock only during probe.
However, if the clock is re-parented to the VIDEO_PLL, changes to the
pixel clock have an effect on the PLL ref clock. Therefore, the driver
must read and potentially update the PLL ref clock on every modeset.

I also found that the rounding mode of the porches and active area has
an effect on the working modes. If the driver rounds up instead of
rounding down and be calculates them in Hz instead of kHz, more modes
start to work.

The following table shows the modes that were working in my test without
this patch set and the modes that are working now:

|            Mode | Before | Now |
| 1920x1080-60.00 | X      | X   |
| 1920x1080-59.94 |        | X   |
| 1920x1080-50.00 |        | X   |
| 1920x1080-30.00 |        | X   |
| 1920x1080-29.97 |        | X   |
| 1920x1080-25.00 |        | X   |
| 1920x1080-24.00 |        |     |
| 1920x1080-23.98 |        |     |
| 1680x1050-59.88 |        | X   |
| 1280x1024-75.03 | X      | X   |
| 1280x1024-60.02 | X      | X   |
|  1200x960-59.99 |        | X   |
|  1152x864-75.00 | X      | X   |
|  1280x720-60.00 |        |     |
|  1280x720-59.94 |        |     |
|  1280x720-50.00 |        | X   |
|  1024x768-75.03 |        | X   |
|  1024x768-60.00 |        | X   |
|   800x600-75.00 | X      | X   |
|   800x600-60.32 | X      | X   |
|   720x576-50.00 | X      | X   |
|   720x480-60.00 |        |     |
|   720x480-59.94 | X      |     |
|   640x480-75.00 | X      | X   |
|   640x480-60.00 |        | X   |
|   640x480-59.94 |        | X   |
|   720x400-70.08 |        |     |

Interestingly, the 720x480-59.94 mode stopped working. However, I am
able to bring up the 720x480 modes by manually hacking the active area
(hsa) to 40 and carefully adjusting the clocks, but something still
seems to be off.

Unfortunately, a few more modes are still not working at all. The NXP
downstream kernel has some quirks to handle some of the modes especially
wrt. to the porches, but I cannot figure out, what the driver should
actually do in these cases. Maybe there is still an error in the
calculation of the porches and someone at NXP can chime in.

Michael

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
---
Changes in v2:
- Specify limits for the PLL input clock in samsung_dsim_driver_data
- Rephrase/clarify commit messages
- Link to v1: https://lore.kernel.org/r/20230818-samsung-dsim-v1-0-b39716db6b7a@pengutronix.de

---
Marco Felsch (1):
      drm/bridge: samsung-dsim: add more mipi-dsi device debug information

Michael Tretter (4):
      drm/bridge: samsung-dsim: reread ref clock before configuring PLL
      drm/bridge: samsung-dsim: update PLL reference clock
      drm/bridge: samsung-dsim: adjust porches by rounding up
      drm/bridge: samsung-dsim: calculate porches in Hz

 drivers/gpu/drm/bridge/samsung-dsim.c | 54 +++++++++++++++++++++++++++--------
 include/drm/bridge/samsung-dsim.h     |  3 ++
 2 files changed, 45 insertions(+), 12 deletions(-)
---
base-commit: b78b18fb8ee19f7a05f20c3abc865b3bfe182884
change-id: 20230818-samsung-dsim-42346444bce5

Best regards,
  

On 06.10.2023 17:07, Michael Tretter wrote:
> I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter,
> which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few
> modes were working, but in many modes my monitor stayed dark.
>
> This series fixes the Samsung DSIM bridge driver to bring up a few more
> modes:
>
> The driver read the rate of the PLL ref clock only during probe.
> However, if the clock is re-parented to the VIDEO_PLL, changes to the
> pixel clock have an effect on the PLL ref clock. Therefore, the driver
> must read and potentially update the PLL ref clock on every modeset.
>
> I also found that the rounding mode of the porches and active area has
> an effect on the working modes. If the driver rounds up instead of
> rounding down and be calculates them in Hz instead of kHz, more modes
> start to work.
>
> The following table shows the modes that were working in my test without
> this patch set and the modes that are working now:
>
> |            Mode | Before | Now |
> | 1920x1080-60.00 | X      | X   |
> | 1920x1080-59.94 |        | X   |
> | 1920x1080-50.00 |        | X   |
> | 1920x1080-30.00 |        | X   |
> | 1920x1080-29.97 |        | X   |
> | 1920x1080-25.00 |        | X   |
> | 1920x1080-24.00 |        |     |
> | 1920x1080-23.98 |        |     |
> | 1680x1050-59.88 |        | X   |
> | 1280x1024-75.03 | X      | X   |
> | 1280x1024-60.02 | X      | X   |
> |  1200x960-59.99 |        | X   |
> |  1152x864-75.00 | X      | X   |
> |  1280x720-60.00 |        |     |
> |  1280x720-59.94 |        |     |
> |  1280x720-50.00 |        | X   |
> |  1024x768-75.03 |        | X   |
> |  1024x768-60.00 |        | X   |
> |   800x600-75.00 | X      | X   |
> |   800x600-60.32 | X      | X   |
> |   720x576-50.00 | X      | X   |
> |   720x480-60.00 |        |     |
> |   720x480-59.94 | X      |     |
> |   640x480-75.00 | X      | X   |
> |   640x480-60.00 |        | X   |
> |   640x480-59.94 |        | X   |
> |   720x400-70.08 |        |     |
>
> Interestingly, the 720x480-59.94 mode stopped working. However, I am
> able to bring up the 720x480 modes by manually hacking the active area
> (hsa) to 40 and carefully adjusting the clocks, but something still
> seems to be off.
>
> Unfortunately, a few more modes are still not working at all. The NXP
> downstream kernel has some quirks to handle some of the modes especially
> wrt. to the porches, but I cannot figure out, what the driver should
> actually do in these cases. Maybe there is still an error in the
> calculation of the porches and someone at NXP can chime in.
>
> Michael
>
> Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>

All my Exynos-based test boards with DSI display panels still work fine 
with this patchset.

Feel free to add:

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>


> ---
> Changes in v2:
> - Specify limits for the PLL input clock in samsung_dsim_driver_data
> - Rephrase/clarify commit messages
> - Link to v1: https://lore.kernel.org/r/20230818-samsung-dsim-v1-0-b39716db6b7a@pengutronix.de
>
> ---
> Marco Felsch (1):
>        drm/bridge: samsung-dsim: add more mipi-dsi device debug information
>
> Michael Tretter (4):
>        drm/bridge: samsung-dsim: reread ref clock before configuring PLL
>        drm/bridge: samsung-dsim: update PLL reference clock
>        drm/bridge: samsung-dsim: adjust porches by rounding up
>        drm/bridge: samsung-dsim: calculate porches in Hz
>
>   drivers/gpu/drm/bridge/samsung-dsim.c | 54 +++++++++++++++++++++++++++--------
>   include/drm/bridge/samsung-dsim.h     |  3 ++
>   2 files changed, 45 insertions(+), 12 deletions(-)
> ---
> base-commit: b78b18fb8ee19f7a05f20c3abc865b3bfe182884
> change-id: 20230818-samsung-dsim-42346444bce5
>
> Best regards,

Best regards
  

Hi,

On Fri, 06 Oct 2023 17:07:02 +0200, Michael Tretter wrote:
> I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter,
> which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few
> modes were working, but in many modes my monitor stayed dark.
> 
> This series fixes the Samsung DSIM bridge driver to bring up a few more
> modes:
> 
> [...]

Thanks, Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)

[1/5] drm/bridge: samsung-dsim: add more mipi-dsi device debug information
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=3683182a7254f728778452814abe2437a12502c3
[2/5] drm/bridge: samsung-dsim: reread ref clock before configuring PLL
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=eb26c6ab2a11e6c595ee88ce30c7de9578d957aa
[3/5] drm/bridge: samsung-dsim: update PLL reference clock
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=846307185f0ffbbe6b34d53b97c31c0fc392cff0
[4/5] drm/bridge: samsung-dsim: adjust porches by rounding up
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=198e54282ae560958e64328fe8f72893661b9e8b
[5/5] drm/bridge: samsung-dsim: calculate porches in Hz
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=6acb691824933535219dfd94d9d97c922f5593d2