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authorDaniel Mack <daniel@caiaq.de>2009-11-19 19:01:42 +0000
committerGrant Likely <grant.likely@secretlab.ca>2009-12-08 18:48:16 -0700
commitce1807b2e527979bd77d8a1a1768a6365f3febb5 (patch)
tree2bbf8ecbf000083f147fab885bdb91894c56186a
parentd33c861e71c57dd69d39d88b84a672adf86a2144 (diff)
spi/i.mx: drain MXC SPI transfer buffer when probing device
On the MX31litekit, the bootloader seems to communicate with the MC13783 PMIC chip before booting Linux. However, it does not flush all the buffers properly after that, which makes the imx-spi driver read bogus data when probing the MC13783. Fix that by draining the SPI receive buffer on startup. Signed-off-by: Daniel Mack <daniel@caiaq.de> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
-rw-r--r--drivers/spi/spi_imx.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 89c22efedfb..1b17f443dee 100644
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -44,6 +44,9 @@
#define MXC_CSPIINT 0x0c
#define MXC_RESET 0x1c
+#define MX3_CSPISTAT 0x14
+#define MX3_CSPISTAT_RR (1 << 3)
+
/* generic defines to abstract from the different register layouts */
#define MXC_INT_RR (1 << 0) /* Receive data ready interrupt */
#define MXC_INT_TE (1 << 1) /* Transmit FIFO empty interrupt */
@@ -593,6 +596,11 @@ static int __init spi_imx_probe(struct platform_device *pdev)
if (!cpu_is_mx31() || !cpu_is_mx35())
writel(1, spi_imx->base + MXC_RESET);
+ /* drain receive buffer */
+ if (cpu_is_mx31() || cpu_is_mx35())
+ while (readl(spi_imx->base + MX3_CSPISTAT) & MX3_CSPISTAT_RR)
+ readl(spi_imx->base + MXC_CSPIRXDATA);
+
spi_imx->intctrl(spi_imx, 0);
ret = spi_bitbang_start(&spi_imx->bitbang);