[U-Boot] [PATCH 07/13] i.MX28: Shut down the LCD controller before reset

Marek Vasut marex at denx.de
Tue May 1 23:09:47 CEST 2012


If the LCD controller is on before the CPU goes into reset, the traffic on LCDIF
data pins interferes with the BootROM's boot mode sampling. So shut the
controller down.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Detlev Zundel <dzu at denx.de>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: Wolfgang Denk <wd at denx.de>
---
 arch/arm/cpu/arm926ejs/mx28/mx28.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/cpu/arm926ejs/mx28/mx28.c b/arch/arm/cpu/arm926ejs/mx28/mx28.c
index 865dbb3..a82ff25 100644
--- a/arch/arm/cpu/arm926ejs/mx28/mx28.c
+++ b/arch/arm/cpu/arm926ejs/mx28/mx28.c
@@ -51,9 +51,16 @@ void reset_cpu(ulong ignored) __attribute__((noreturn));
 
 void reset_cpu(ulong ignored)
 {
-
 	struct mx28_rtc_regs *rtc_regs =
 		(struct mx28_rtc_regs *)MXS_RTC_BASE;
+	struct mx28_lcdif_regs *lcdif_regs =
+		(struct mx28_lcdif_regs *)MXS_LCDIF_BASE;
+
+	/*
+	 * Shut down the LCD controller as it interferes with BootROM boot mode
+	 * pads sampling.
+	 */
+	writel(LCDIF_CTRL_RUN, &lcdif_regs->hw_lcdif_ctrl_clr);
 
 	/* Wait 1 uS before doing the actual watchdog reset */
 	writel(1, &rtc_regs->hw_rtc_watchdog);
-- 
1.7.10



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