From 078078cfa91f72331421e6f7a46938a58a9b21a7 Mon Sep 17 00:00:00 2001
From: Tom Warren <twarren@nvidia.com>
Date: Tue, 15 May 2012 14:32:40 -0700
Subject: spi: Tegra2: Seaboard: fix UART corruption during SPI transactions

Simon Glass's proposal to fix this on Seaboard was NAK'd, so I
removed his NS16550 references and added a small delay before
SPI/UART muxing. Tested on my Seaboard with large SPI reads/writes
and saw no corruption (crc's matched) and no spurious comm chars.

Signed-off-by: Tom Warren <twarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Jimmy Zhang <jimmzhang@nvidia.com>
---
 drivers/spi/tegra2_spi.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/spi/tegra2_spi.c b/drivers/spi/tegra2_spi.c
index 56cb229..fe7b405 100644
--- a/drivers/spi/tegra2_spi.c
+++ b/drivers/spi/tegra2_spi.c
@@ -28,13 +28,18 @@
 #include <spi.h>
 #include <asm/io.h>
 #include <asm/gpio.h>
-#include <ns16550.h>
 #include <asm/arch/clk_rst.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/pinmux.h>
 #include <asm/arch/uart-spi-switch.h>
 #include <asm/arch/tegra2_spi.h>
 
+#if defined(CONFIG_SPI_CORRUPTS_UART)
+ #define corrupt_delay()	udelay(CONFIG_SPI_CORRUPTS_UART_DLY);
+#else
+ #define corrupt_delay()
+#endif
+
 struct tegra_spi_slave {
 	struct spi_slave slave;
 	struct spi_tegra *regs;
@@ -161,14 +166,20 @@ void spi_cs_activate(struct spi_slave *slave)
 
 	/* CS is negated on Tegra, so drive a 1 to get a 0 */
 	setbits_le32(&spi->regs->command, SPI_CMD_CS_VAL);
+
+	corrupt_delay();		/* Let UART settle */
 }
 
 void spi_cs_deactivate(struct spi_slave *slave)
 {
 	struct tegra_spi_slave *spi = to_tegra_spi(slave);
 
+	pinmux_select_uart();
+
 	/* CS is negated on Tegra, so drive a 0 to get a 1 */
 	clrbits_le32(&spi->regs->command, SPI_CMD_CS_VAL);
+
+	corrupt_delay();		/* Let SPI settle */
 }
 
 int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
-- 
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