Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Stefan Wahren <stefan.wahren@i2se.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-spi@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	Martin Sperl <kernel@martin.sperl.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 4.4 071/174] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios
Date: Thu, 16 Jan 2020 12:41:08 -0500
Message-ID: <20200116174251.24326-71-sashal@kernel.org> (raw)
In-Reply-To: <20200116174251.24326-1-sashal@kernel.org>

From: Martin Sperl <kernel@martin.sperl.org>

[ Upstream commit 509c583620e9053e43d611bf1614fc3d3abafa96 ]

The original driver by default defines num_chipselects as -1.
This actually allicates an array of 65535 entries in
of_spi_register_master.

There is a side-effect for buggy device trees that (contrary to
dt-binding documentation) have no cs-gpio defined.

This mode was never supported by the driver due to limitations
of native cs and additional code complexity and is explicitly
not stated to be implemented.

To keep backwards compatibility with such buggy DTs we limit
the number of chip_selects to 1, as for all practical purposes
it is only ever realistic to use a single chip select in
native cs mode without negative side-effects.

Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...")
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-bcm2835aux.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index ca655593c5e0..1cedd640705f 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -390,7 +390,18 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, master);
 	master->mode_bits = BCM2835_AUX_SPI_MODE_BITS;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
-	master->num_chipselect = -1;
+	/* even though the driver never officially supported native CS
+	 * allow a single native CS for legacy DT support purposes when
+	 * no cs-gpio is configured.
+	 * Known limitations for native cs are:
+	 * * multiple chip-selects: cs0-cs2 are all simultaniously asserted
+	 *     whenever there is a transfer -  this even includes SPI_NO_CS
+	 * * SPI_CS_HIGH: is ignores - cs are always asserted low
+	 * * cs_change: cs is deasserted after each spi_transfer
+	 * * cs_delay_usec: cs is always deasserted one SCK cycle after
+	 *     a spi_transfer
+	 */
+	master->num_chipselect = 1;
 	master->transfer_one = bcm2835aux_spi_transfer_one;
 	master->handle_err = bcm2835aux_spi_handle_err;
 	master->dev.of_node = pdev->dev.of_node;
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116174251.24326-1-sashal@kernel.org>
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 022/174] clk: samsung: exynos4: fix refcount leak in exynos4_get_xom() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 023/174] clk: imx6q: fix refcount leak in imx6q_clocks_init() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 024/174] clk: imx6sx: fix refcount leak in imx6sx_clocks_init() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 025/174] clk: imx7d: fix refcount leak in imx7d_clocks_init() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 026/174] clk: vf610: fix refcount leak in vf610_clocks_init() Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 032/174] media: s5p-jpeg: Correct step and max values for V4L2_CID_JPEG_RESTART_INTERVAL Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 034/174] ASoC: imx-sgtl5000: put of nodes if finding codec fails Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 052/174] clocksource/drivers/sun5i: Fail gracefully when clock rate is unavailable Sasha Levin
2020-01-16 17:40 ` [PATCH AUTOSEL 4.4 053/174] ARM: 8847/1: pm: fix HYP/SVC mode mismatch when MCPM is used Sasha Levin
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 065/174] ARM: OMAP2+: Fix potentially uninitialized return value for _setup_reset() Sasha Levin
2020-01-16 17:41 ` Sasha Levin [this message]
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 074/174] ARM: pxa: ssp: Fix "WARNING: invalid free of devm_ allocated data" Sasha Levin
2020-01-16 17:41 ` [PATCH AUTOSEL 4.4 090/174] ARM: riscpc: fix lack of keyboard interrupts after irq conversion Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 142/174] net: ethernet: stmmac: Fix signedness bug in ipq806x_gmac_of_parse() Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 146/174] net: stmmac: fix length of PTP clock's name string Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 149/174] dmaengine: imx-sdma: fix size check for sdma script_number Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 151/174] mt7601u: fix bbp version check in mt7601u_wait_bbp_ready Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 156/174] spi: atmel: fix handling of cs_change set on non-last xfer Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 159/174] clk: samsung: exynos5420: Preserve CPU clocks configuration during suspend/resume Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 161/174] media: exynos4-is: Fix recursive locking in isp_video_release() Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 165/174] tty: serial: imx: use the sg count from dma_map_sg Sasha Levin
2020-01-16 17:42 ` [PATCH AUTOSEL 4.4 173/174] arm64: dts: juno: Fix UART frequency Sasha Levin

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200116174251.24326-71-sashal@kernel.org \
    --to=sashal@kernel.org \
    --cc=bcm-kernel-feedback-list@broadcom.com \
    --cc=broonie@kernel.org \
    --cc=kernel@martin.sperl.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rpi-kernel@lists.infradead.org \
    --cc=linux-spi@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=stefan.wahren@i2se.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git