Re: [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