Messages in this thread Patch in this message | | | From | Sven Van Asbroeck <> | Subject | [PATCH net v2] net: phy: spi_ks8995: Do not overwrite SPI mode flags | Date | Tue, 10 Nov 2020 09:20:32 -0500 |
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From: Sven Van Asbroeck <thesven73@gmail.com>
This driver makes sure the underlying SPI bus is set to "mode 0" by assigning SPI_MODE_0 to spi->mode. Which overwrites all other SPI mode flags.
In some circumstances, this can break the underlying SPI bus driver. For example, if SPI_CS_HIGH is set on the SPI bus, the driver will clear that flag, which results in a chip-select polarity issue.
Fix by changing only the SPI_MODE_N bits, i.e. SPI_CPHA and SPI_CPOL.
Fixes: a8e510f682fe ("phy: Micrel KS8995MA 5-ports 10/100 managed Ethernet switch support added") Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs") Link: https://patchwork.kernel.org/project/spi-devel-general/patch/20201106150706.29089-1-TheSven73@gmail.com/#23747737 Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> ---
Tree: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git # 989ef49bdf10
To be followed by a proposed spi helper function. Submit to net-next after net gets merged into net-next.
# large number of people, from get_maintainer.pl To: Andrew Lunn <andrew@lunn.ch> To: Heiner Kallweit <hkallweit1@gmail.com> To: Jakub Kicinski <kuba@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org
Cc: Mark Brown <broonie@kernel.org> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Frederic LAMBERT <frdrc66@gmail.com> Cc: Gabor Juhos <juhosg@openwrt.org> Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
# Cc SPI group, suggested by Jakub Kicinski Cc: linux-spi@vger.kernel.org
drivers/net/phy/spi_ks8995.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/spi_ks8995.c b/drivers/net/phy/spi_ks8995.c index 4b198399bfa2..3c6c87a09b03 100644 --- a/drivers/net/phy/spi_ks8995.c +++ b/drivers/net/phy/spi_ks8995.c @@ -491,7 +491,9 @@ static int ks8995_probe(struct spi_device *spi) spi_set_drvdata(spi, ks); - spi->mode = SPI_MODE_0; + /* use SPI_MODE_0 without changing any other mode flags */ + spi->mode &= ~(SPI_CPHA | SPI_CPOL); + spi->mode |= SPI_MODE_0; spi->bits_per_word = 8; err = spi_setup(spi); if (err) { -- 2.17.1
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