[PATCH] atmel_lcdfb: LCDC startup fix

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From: Anti Sullin <[email protected]>

This patch adds an additional loop, that delays turning off the DMA until the LCDC core has been turned off. This prevents the picture to be shifted some random length when the kernel re-initializes
the LCDC.

Signed-off-by: Anti Sullin <[email protected]>
Signed-off-by: Andrew Victor <[email protected]>
Signed-off-by: Nicolas Ferre <[email protected]>
Acked-by: Haavard Skinnemoen <[email protected]>
---

Without this patch, the LCDC keeps running for some small time after the PWRCON:LCD_PWR has been cleared ; the FIFO suffers an underrun and on re-starting the LCDC the FIFO data stays shifted. This behavior has been seen and fixed on AT91SAM9261-EK and two custom AT91SAM9261 boards, all of them having different LCD panels.

Thanks a lot to Anti Sullin for submitting this patch (long time ago).

--- a/drivers/video/atmel_lcdfb.c
+++ b/drivers/video/atmel_lcdfb.c
@@ -268,6 +268,10 @@
	/* Turn off the LCD controller and the DMA controller */
	lcdc_writel(sinfo, ATMEL_LCDC_PWRCON, sinfo->guard_time << ATMEL_LCDC_GUARDT_OFFSET);

+	/* Wait for the LCDC core to become idle */
+	while (lcdc_readl(sinfo, ATMEL_LCDC_PWRCON) & ATMEL_LCDC_BUSY)
+		msleep(10);
+
	lcdc_writel(sinfo, ATMEL_LCDC_DMACON, 0);

	if (info->var.bits_per_pixel == 1)
-
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