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drm/omap: tweak HDMI DDC timings
authorAlejandro Hernandez <ajhernandez@ti.com>
Mon, 30 Sep 2019 10:38:36 +0000 (13:38 +0300)
committerTomi Valkeinen <tomi.valkeinen@ti.com>
Fri, 4 Oct 2019 08:30:28 +0000 (11:30 +0300)
A "HDMI I2C Master Error" is sometimes reported with the current DDC SCL
timings. The current settings for a 10us SCL period (100 KHz) causes the
error with some displays.  This patch increases the SCL signal period
from 10us to 10.2us, with the new settings the error is not observed

Signed-off-by: Alejandro Hernandez <ajhernandez@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190930103840.18970-4-tomi.valkeinen@ti.com
drivers/gpu/drm/omapdrm/dss/hdmi5_core.c

index 7400fb9..4c588ec 100644 (file)
@@ -39,8 +39,8 @@ static void hdmi_core_ddc_init(struct hdmi_core_data *core)
 {
        void __iomem *base = core->base;
        const unsigned long long iclk = 266000000;      /* DSS L3 ICLK */
-       const unsigned int ss_scl_high = 4600;          /* ns */
-       const unsigned int ss_scl_low = 5400;           /* ns */
+       const unsigned int ss_scl_high = 4700;          /* ns */
+       const unsigned int ss_scl_low = 5500;           /* ns */
        const unsigned int fs_scl_high = 600;           /* ns */
        const unsigned int fs_scl_low = 1300;           /* ns */
        const unsigned int sda_hold = 1000;             /* ns */