4.2.8-ckt1 -stable review patch. If anyone has any objections, please let me
know.
------------------
From: Neil Armstrong <narmstr...@baylibre.com>
commit 468a32082b04c7febccfcd55b06ecbc438fcddcc upstream.
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: b28cb9414db9 ("spi: omap2-mcspi: Switch driver to use transfer_one")
Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
Reviewed-by: Michael Welling <mwell...@ieee.org>
Signed-off-by: Mark Brown <broo...@kernel.org>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
drivers/spi/spi-omap2-mcspi.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 3d09e0b..1f8903d 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -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;
--
1.9.1
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