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 <aford...@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
 
 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 {
                                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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