Re: [PATCH V6 0/6] drm: bridge: samsung-dsim: Support variable clocking

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 16.05.2023 01:57, Adam Ford wrote:
> This series fixes the blanking pack size and the PMS calculation.  It then
> adds support to allows the DSIM to dynamically DPHY clocks, and support
> non-burst mode while allowing the removal of the hard-coded clock values
> for the PLL for imx8m mini/nano/plus, and it allows the removal of the
> burst-clock device tree entry when burst-mode isn't supported by connected
> devices like an HDMI brige.  In that event, the HS clock is set to the
> value requested by the bridge chip.
>
> This has been tested on both an i.MX8M Nano and i.MX8M Plus, and should
> work on i.MX8M Mini as well. Marek Szyprowski has tested it on various
> Exynos boards.
>
> Adam Ford (5):
>    drm: bridge: samsung-dsim: Fix PMS Calculator on imx8m[mnp]
>    drm: bridge: samsung-dsim: Fetch pll-clock-frequency automatically
>    drm: bridge: samsung-dsim: Select GENERIC_PHY_MIPI_DPHY
>    drm: bridge: samsung-dsim: Dynamically configure DPHY timing
>    drm: bridge: samsung-dsim: Support non-burst mode
>
> Lucas Stach (1):
>    drm: bridge: samsung-dsim: fix blanking packet size calculation
>
>   drivers/gpu/drm/bridge/Kconfig        |   1 +
>   drivers/gpu/drm/bridge/samsung-dsim.c | 143 +++++++++++++++++++++-----
>   include/drm/bridge/samsung-dsim.h     |   4 +
>   3 files changed, 125 insertions(+), 23 deletions(-)

Feel free to add to all patches:

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


> V6:  Squash-in an additional error fix from Lucas Stach regarding the
>       DPHY calcuations.  Remove the dynamic_dphy variable and let
>       everyone use the new calculations.  Move the hs_clock caching
>       from patch 6 to patch 5 to go along with the DPHY calcuations
>       since they are now based on the recorded hs_clock rate.
>       
> V5:  Update error message to dev_info and change them to indicate
>       what is happening without sounding like an error when optional
>       device tree entries are missing.
>
> V4:  Undo some accidental whitespace changes, rename PS_TO_CYCLE
>       variables to ps and hz from PS and MHz. Remove if check
>       before the samsung_dsim_set_phy_ctrl call since it's
>       unnecessary.
>       Added additional tested-by and reviewed-by comments.
>       Squash patches 6 and 7 together since the supporting
>       non-burst (patch 6) mode doesn't really work until
>       patch 7 was applied.
>
> V3:  When checking if the bust-clock is present, only check for it
>       in the device tree, and don't check the presence of the
>       MIPI_DSI_MODE_VIDEO_BURST flag as it breaks an existing Exynos
>       board.
>
>       Add a new patch to the series to select GENERIC_PHY_MIPI_DPHY in
>       Kconfig otherwise the build breaks on the 32-bit Exynos.
>
>       Change vco_min variable name to min_freq
>
>       Added tested-by from Chen-Yu Tsai
>
> V2:  Instead of using my packet blanking calculation, this integrates
>       on from Lucas Stach which gets modified later in the series to
>       cache the value of the HS-clock instead of having to do the
>       calucations again.
>
>       Instead of completely eliminating the PLL clock frequency from
>       the device tree, this makes it optional to avoid breaking some
>       Samsung devices.  When the samsung,pll-clock-frequency is not
>       found, it reads the value of the clock named "sclk_mipi"
>       This also maintains backwards compatibility with older device
>       trees.
>
>       This also changes the DPHY calcuation from a Look-up table,
>       a reverse engineered algorithm which uses
>       phy_mipi_dphy_get_default_config to determine the standard
>       nominal values and calculates the cycles necessary to update
>       the DPHY timings accordingly.
>       

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland