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| author | Charles Keepax <ckeepax@opensource.cirrus.com> | 2019-11-26 16:41:40 +0000 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-11-27 12:54:45 +0000 |
| commit | 61acd19f9c56fa0809285346bd0bd4a926ab0da0 (patch) | |
| tree | 6918c3f096322393de0dad8abb3a8dbf17a8573a /drivers/spi/spi-cadence.c | |
| parent | 9c7315c9fca5de203538163cf42699bb10328902 (diff) | |
| download | lwn-61acd19f9c56fa0809285346bd0bd4a926ab0da0.tar.gz lwn-61acd19f9c56fa0809285346bd0bd4a926ab0da0.zip | |
spi: cadence: Correct handling of native chipselect
To fix a regression on the Cadence SPI driver, this patch reverts
commit 6046f5407ff0 ("spi: cadence: Fix default polarity of native
chipselect").
This patch was not the correct fix for the issue. The SPI framework
calls the set_cs line with the logic level it desires on the chip select
line, as such the old is_high handling was correct. However, this was
broken by the fact that before commit 3e5ec1db8bfe ("spi: Fix SPI_CS_HIGH
setting when using native and GPIO CS") all controllers that offered
the use of a GPIO chip select had SPI_CS_HIGH applied, even for hardware
chip selects. This caused the value passed into the driver to be inverted.
Which unfortunately makes it look like a logical enable the chip select
value.
Since the core was corrected to not unconditionally apply SPI_CS_HIGH,
the Cadence driver, whilst using the hardware chip select, will deselect
the chip select every time we attempt to communicate with the device,
which results in failed communications.
Fixes: 3e5ec1db8bfe ("spi: Fix SPI_CS_HIGH setting when using native and GPIO CS")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20191126164140.6240-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-cadence.c')
| -rw-r--r-- | drivers/spi/spi-cadence.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c index c36587b42e95..82a0ee09cbe1 100644 --- a/drivers/spi/spi-cadence.c +++ b/drivers/spi/spi-cadence.c @@ -168,16 +168,16 @@ static void cdns_spi_init_hw(struct cdns_spi *xspi) /** * cdns_spi_chipselect - Select or deselect the chip select line * @spi: Pointer to the spi_device structure - * @enable: Select (1) or deselect (0) the chip select line + * @is_high: Select(0) or deselect (1) the chip select line */ -static void cdns_spi_chipselect(struct spi_device *spi, bool enable) +static void cdns_spi_chipselect(struct spi_device *spi, bool is_high) { struct cdns_spi *xspi = spi_master_get_devdata(spi->master); u32 ctrl_reg; ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR); - if (!enable) { + if (is_high) { /* Deselect the slave */ ctrl_reg |= CDNS_SPI_CR_SSCTRL; } else { |