----- Original Message -----
From: "Gregory CLEMENT" <gregory.clement@xxxxxxxxxxxxxxxxxx>
To: "spi-devel-general" <spi-devel-general@xxxxxxxxxxxxxxxxxxxxx>;
"linux-omap" <linux-omap@xxxxxxxxxxxxxxx>
Cc: "David Brownell" <dbrownell@xxxxxxxxxxxxxxxxxxxxx>; "Grant Likely"
<grant.likely@xxxxxxxxxxxx>; "Kevin Hilman" <khilman@xxxxxxxxxxxxxxxxxxx>
Sent: Wednesday, November 10, 2010 4:02 PM
Subject: [PATCH v2 2/2] spi: Force CS to be in inactive state after off-mode
transition
When SPI wake up from OFF mode, CS is in the wrong state: force it to the
inactive state.
During the system life, I monitored the CS behavior using a oscilloscope.
I also activated debug in omap2_mcspi, so I saw when driver disable the
clocks and restore context when device is not used.
Each time the CS was in the correct state.
It was only when system was put suspend to ram with off-mode activated
that on resume the CS was in wrong state( ie activated).
Just to confirm the understanding. Are saying CHCONF[6] EPOL bit
setting and CS state did not match and is actually a hardware bug. If so
could u let us know which platform u are testing this on.
Thanks
Hemanth
Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
---
drivers/spi/omap2_mcspi.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index 2a651e6..938f14c 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -1139,6 +1139,15 @@ static u8 __initdata spi4_txdma_id[] = {
};
#endif
+/* When SPI wake up, CS is in wrong state: force it to unactive state*/
+static void omap2_mcspi_resume(struct spi_device *spi)
+{
+ omap2_mcspi_enable_clocks( spi_master_get_devdata(spi->master));
+ /* We need to togle CS state for OMAP take this chang in account*/
+ omap2_mcspi_force_cs(spi, 1);
+ omap2_mcspi_force_cs(spi, 0);
+ omap2_mcspi_disable_clocks( spi_master_get_devdata(spi->master));
+}
static int __init omap2_mcspi_probe(struct platform_device *pdev)
{
struct spi_master *master;
@@ -1194,6 +1203,7 @@ static int __init omap2_mcspi_probe(struct
platform_device *pdev)
master->transfer = omap2_mcspi_transfer;
master->cleanup = omap2_mcspi_cleanup;
master->num_chipselect = num_chipselect;
+ master->resume = omap2_mcspi_resume;
dev_set_drvdata(&pdev->dev, master);
-- 1.7.0.4
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