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spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message 

Since the "Switch driver to use transfer_one" change, the cs_change
behavior has changed and a channel chip select can still be
asserted when changing channel from a previous last transfer in a
message having the cs_change attribute.

Since there is no sense having multiple chip select being asserted at the
same time, disable all the remaining forced chip selects in a the
prepare_message called right before a spi_transfer_one_message call.
It ignores the current channel configuration in order to keep the
possibility to leave the chip select asserted between messages.

It fixes this bug on a DM8168 SoC ES2.1 Soc and an OMAP4 ES2.1 SoC.
It was hanging all the other channels transfers when a CHCONF_FORCE
is present on the wrong channel.

Fixes: b28cb9414d ("spi: omap2-mcspi: Switch driver to use transfer_one")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Michael Welling <mwelling@ieee.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Neil Armstrong 2015-10-09 15:47:41 +02:00 committed by Mark Brown
parent 6ff33f3902
commit 468a32082b
1 changed files with 28 additions and 0 deletions
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28
drivers/spi/spi-omap2-mcspi.c
View File

@ -1217,6 +1217,33 @@ out:
return status;
}
static int omap2_mcspi_prepare_message(struct spi_master *master,
struct spi_message *msg)
{
struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
struct omap2_mcspi_regs *ctx = &mcspi->ctx;
struct omap2_mcspi_cs *cs;
/* Only a single channel can have the FORCE bit enabled
* in its chconf0 register.
* Scan all channels and disable them except the current one.
* A FORCE can remain from a last transfer having cs_change enabled
*/
list_for_each_entry(cs, &ctx->cs, node) {
if (msg->spi->controller_state == cs)
continue;
if ((cs->chconf0 & OMAP2_MCSPI_CHCONF_FORCE)) {
cs->chconf0 &= ~OMAP2_MCSPI_CHCONF_FORCE;
writel_relaxed(cs->chconf0,
cs->base + OMAP2_MCSPI_CHCONF0);
readl_relaxed(cs->base + OMAP2_MCSPI_CHCONF0);
}
}
return 0;
}
static int omap2_mcspi_transfer_one(struct spi_master *master,
struct spi_device *spi, struct spi_transfer *t)
{
@ -1344,6 +1371,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
master->setup = omap2_mcspi_setup;
master->auto_runtime_pm = true;
master->prepare_message = omap2_mcspi_prepare_message;
master->transfer_one = omap2_mcspi_transfer_one;
master->set_cs = omap2_mcspi_set_cs;
master->cleanup = omap2_mcspi_cleanup;