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OMAPDSS: HDMI5: Change DDC timings

The DDC scl high and low times were set to the minimum values
from the i2c specification, but the i2c specification takes into
account the rise time and fall time to calculate the frequency.
To pass HDMI certification DDC can not exceed 100kHz therefore in
a system where the rise times and fall times are negligible the high
and low times for scl need to be 10us.

Signed-off-by: Jim Lodes <jim.lodes@garmin.com>
Signed-off-by: J.D. Schroeder <jay.schroeder@garmin.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Jim Lodes 9 년 전
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2개의 변경된 파일4개의 추가작업 그리고 4개의 파일을 삭제
  1. 2 2
      drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
  2. 2 2
      drivers/video/fbdev/omap2/omapfb/dss/hdmi5_core.c

+ 2 - 2
drivers/gpu/drm/omapdrm/dss/hdmi5_core.c

@@ -51,8 +51,8 @@ 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 ss_scl_high = 4000;		/* ns */
-	const unsigned ss_scl_low = 4700;		/* ns */
+	const unsigned ss_scl_high = 4600;		/* ns */
+	const unsigned ss_scl_low = 5400;		/* ns */
 	const unsigned fs_scl_high = 600;		/* ns */
 	const unsigned fs_scl_low = 1300;		/* ns */
 	const unsigned sda_hold = 1000;			/* ns */

+ 2 - 2
drivers/video/fbdev/omap2/omapfb/dss/hdmi5_core.c

@@ -51,8 +51,8 @@ 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 ss_scl_high = 4000;		/* ns */
-	const unsigned ss_scl_low = 4700;		/* ns */
+	const unsigned ss_scl_high = 4600;		/* ns */
+	const unsigned ss_scl_low = 5400;		/* ns */
 	const unsigned fs_scl_high = 600;		/* ns */
 	const unsigned fs_scl_low = 1300;		/* ns */
 	const unsigned sda_hold = 1000;			/* ns */