[PATCH] video: da8xx-fb: preserve display width when changing HSYNC

From: Ian Abbott
Date: Thu Jul 03 2014 - 09:47:53 EST


When looking at this driver for a client, I noticed the code that
configures the HSYNC pulse clobbers the display width in the same
register. It only preserves the MS part of the width in bit 3 and zeros
the LS part of the width in bits 9 to 4. This doesn't matter during
initialization as the width is configured afterwards, but subsequent use
of the FBIPUT_HSYNC ioctl would clobber the width.

Preserve bits 9 to 0 of LCD_RASTER_TIMING_0_REG when configuring the
horizontal sync.

Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
I haven't tested this change, but it's pretty trivial.
---
drivers/video/fbdev/da8xx-fb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/da8xx-fb.c b/drivers/video/fbdev/da8xx-fb.c
index 788f6b3..10c876c 100644
--- a/drivers/video/fbdev/da8xx-fb.c
+++ b/drivers/video/fbdev/da8xx-fb.c
@@ -419,7 +419,7 @@ static void lcd_cfg_horizontal_sync(int back_porch, int pulse_width,
{
u32 reg;

- reg = lcdc_read(LCD_RASTER_TIMING_0_REG) & 0xf;
+ reg = lcdc_read(LCD_RASTER_TIMING_0_REG) & 0x3ff;
reg |= (((back_porch-1) & 0xff) << 24)
| (((front_porch-1) & 0xff) << 16)
| (((pulse_width-1) & 0x3f) << 10);
--
2.0.0

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