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SubjectRe: [PATCH] drm/omap: Migrate minimum FCK/PCK ratio from Kconfig to dts
On Fri, May 10, 2019 at 02:42:29PM -0500, Adam Ford wrote:
> Currently the source code is compiled using hard-coded values
> from CONFIG_OMAP2_DSS_MIN_FCK_PER_PCK. This patch allows this
> clock divider value to be moved to the device tree and be changed
> without having to recompile the kernel.
>
> Signed-off-by: Adam Ford <aford173@gmail.com>
>
> diff --git a/Documentation/devicetree/bindings/display/ti/ti,omap3-dss.txt b/Documentation/devicetree/bindings/display/ti/ti,omap3-dss.txt
> index cd02516a40b6..42449d07c47e 100644
> --- a/Documentation/devicetree/bindings/display/ti/ti,omap3-dss.txt
> +++ b/Documentation/devicetree/bindings/display/ti/ti,omap3-dss.txt
> @@ -40,7 +40,7 @@ Required properties:
> Optional properties:
> - max-memory-bandwidth: Input memory (from main memory to dispc) bandwidth limit
> in bytes per second
> -
> +- min-fck-pck-ratio: Make sure that DISPC FCK is at least n x PCK

Assuming this patch progresses, this needs a vendor prefix and please
split bindings to separate patch.

>
> RFBI
> ----
> diff --git a/arch/arm/boot/dts/omap3.dtsi b/arch/arm/boot/dts/omap3.dtsi
> index 4043ecb38016..bf84a8487aae 100644
> --- a/arch/arm/boot/dts/omap3.dtsi
> +++ b/arch/arm/boot/dts/omap3.dtsi
> @@ -751,7 +751,7 @@
> #size-cells = <1>;
> ranges;
>
> - dispc@48050400 {
> + dispc: dispc@48050400 {

Unrelated change.

> compatible = "ti,omap3-dispc";
> reg = <0x48050400 0x400>;
> interrupts = <25>;
> diff --git a/drivers/gpu/drm/omapdrm/dss/Kconfig b/drivers/gpu/drm/omapdrm/dss/Kconfig
> index f24ebf7f61dd..d0666edcdf2a 100644
> --- a/drivers/gpu/drm/omapdrm/dss/Kconfig
> +++ b/drivers/gpu/drm/omapdrm/dss/Kconfig
> @@ -102,24 +102,6 @@ config OMAP2_DSS_DSI
>
> See http://www.mipi.org/ for DSI specifications.
>
> -config OMAP2_DSS_MIN_FCK_PER_PCK
> - int "Minimum FCK/PCK ratio (for scaling)"
> - range 0 32
> - default 0
> - help
> - This can be used to adjust the minimum FCK/PCK ratio.
> -
> - With this you can make sure that DISPC FCK is at least
> - n x PCK. Video plane scaling requires higher FCK than
> - normally.
> -
> - If this is set to 0, there's no extra constraint on the
> - DISPC FCK. However, the FCK will at minimum be
> - 2xPCK (if active matrix) or 3xPCK (if passive matrix).
> -
> - Max FCK is 173MHz, so this doesn't work if your PCK
> - is very high.
> -
> config OMAP2_DSS_SLEEP_AFTER_VENC_RESET
> bool "Sleep 20ms after VENC reset"
> default y
> diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c
> index ba82d916719c..09a130c53da2 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dispc.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dispc.c
> @@ -198,6 +198,9 @@ struct dispc_device {
>
> /* DISPC_CONTROL & DISPC_CONFIG lock*/
> spinlock_t control_lock;
> +
> + /* Optional min-fck-pck-ratio */
> + u32 min_fck_per_pck;
> };
>
> enum omap_color_component {
> @@ -3683,15 +3686,8 @@ bool dispc_div_calc(struct dispc_device *dispc, unsigned long dispc_freq,
> unsigned long pck, lck;
> unsigned long lck_max;
> unsigned long pckd_hw_min, pckd_hw_max;
> - unsigned int min_fck_per_pck;
> unsigned long fck;
>
> -#ifdef CONFIG_OMAP2_DSS_MIN_FCK_PER_PCK
> - min_fck_per_pck = CONFIG_OMAP2_DSS_MIN_FCK_PER_PCK;
> -#else
> - min_fck_per_pck = 0;
> -#endif
> -
> pckd_hw_min = dispc->feat->min_pcd;
> pckd_hw_max = 255;
>
> @@ -3723,7 +3719,7 @@ bool dispc_div_calc(struct dispc_device *dispc, unsigned long dispc_freq,
> else
> fck = lck;
>
> - if (fck < pck * min_fck_per_pck)
> + if (fck < pck * dispc->min_fck_per_pck)
> continue;
>
> if (func(lckd, pckd, lck, pck, data))
> @@ -4826,6 +4822,8 @@ static int dispc_bind(struct device *dev, struct device *master, void *data)
> }
> }
>
> + of_property_read_u32(np, "min-fck-pck-ratio", &dispc->min_fck_per_pck);
> +
> r = dispc_init_gamma_tables(dispc);
> if (r)
> goto err_free;
> --
> 2.17.1
>

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