From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Neil Armstrong , Michael Welling , Mark Brown Subject: [PATCH 4.3 041/200] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message Date: Sun, 14 Feb 2016 14:20:48 -0800 Message-Id: <20160214222218.624453318@linuxfoundation.org> In-Reply-To: <20160214222217.084543173@linuxfoundation.org> References: <20160214222217.084543173@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Neil Armstrong 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 Reviewed-by: Michael Welling Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi-omap2-mcspi.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) --- 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 plat 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;