From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754045AbcAEULL (ORCPT ); Tue, 5 Jan 2016 15:11:11 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45385 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753699AbcAETs3 (ORCPT ); Tue, 5 Jan 2016 14:48:29 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Neil Armstrong , Mark Brown , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 147/211] spi: omap2-mcspi: disable other channels CHCONF_FORCE in prepare_message Date: Tue, 5 Jan 2016 11:44:15 -0800 Message-Id: <1452023119-25647-148-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1452023119-25647-1-git-send-email-kamal@canonical.com> References: <1452023119-25647-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt1 -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: Kamal Mostafa --- 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