On 11/10/2010 04:57 PM, Grant Likely wrote:
On Wed, Nov 10, 2010 at 11:32:59AM +0100, Gregory CLEMENT wrote:
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).
Sounds like a bug in the suspend/resume path of the spi_master, not
the spi_device. Trying to work around it via the spi_device resume
path is the wrong approach.
OK it was not clear to me that spi_resume() and spi_suspend() were
specifics to devices as these functions belong to a bus structure.
So you suggest to use the suspend/resume functions of the
platform_driver structure of omap2_mcspi_driver, right?
g.
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
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
