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[v2,4/4] drm/bridge: tfp410: Fix setup and hold time calculation

Message ID 20200514143612.2094-5-ricardo.canuelo@collabora.com
State New
Headers show
Series [v2,1/4] ARM: dts: dove: Make the DT compliant with the ti,tfp410 binding | expand

Commit Message

Ricardo Cañuelo May 14, 2020, 2:36 p.m. UTC 
The tfp410 has a data de-skew feature that allows the user to compensate
the skew between IDCK and the pixel data and control signals.

In the driver, the setup and hold times are calculated from the de-skew
value. This retrieves the deskew value from the DT using the proper
datatype and range check as described by the binding (u32 from 0 to 7)
and fixes the calculation of the setup and hold times.

Signed-off-by: Ricardo Cañuelo <ricardo.canuelo@collabora.com>
---
 drivers/gpu/drm/bridge/ti-tfp410.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
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Patch

diff --git a/drivers/gpu/drm/bridge/ti-tfp410.c b/drivers/gpu/drm/bridge/ti-tfp410.c
index e3eb6364c0f7..21d99b4ea0c9 100644
--- a/drivers/gpu/drm/bridge/ti-tfp410.c
+++ b/drivers/gpu/drm/bridge/ti-tfp410.c
@@ -220,7 +220,7 @@  static int tfp410_parse_timings(struct tfp410 *dvi, bool i2c)
 	struct device_node *ep;
 	u32 pclk_sample = 0;
 	u32 bus_width = 24;
-	s32 deskew = 0;
+	u32 deskew = 0;
 
 	/* Start with defaults. */
 	*timings = tfp410_default_timings;
@@ -274,12 +274,12 @@  static int tfp410_parse_timings(struct tfp410 *dvi, bool i2c)
 	}
 
 	/* Get the setup and hold time from vendor-specific properties. */
-	of_property_read_u32(dvi->dev->of_node, "ti,deskew", (u32 *)&deskew);
-	if (deskew < -4 || deskew > 3)
+	of_property_read_u32(dvi->dev->of_node, "ti,deskew", &deskew);
+	if (deskew > 7)
 		return -EINVAL;
 
-	timings->setup_time_ps = min(0, 1200 - 350 * deskew);
-	timings->hold_time_ps = min(0, 1300 + 350 * deskew);
+	timings->setup_time_ps = 1200 - 350 * ((s32)deskew - 4);
+	timings->hold_time_ps = max(0, 1300 + 350 * ((s32)deskew - 4));
 
 	return 0;
 }