From: Andy Shevchenko andriy.shevchenko@linux.intel.com
[ Upstream commit 6b69546912a57ff8c31061f98e56383cc0beffd3 ]
Currently GPIO CS handling, when descriptors are in use, doesn't take into consideration that in ACPI case the default polarity is Active High and can't be altered. Instead we have to use the per-chip definition provided by SPISerialBus() resource.
Fixes: 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors") Cc: Liguang Zhang zhangliguang@linux.alibaba.com Cc: Jay Fang f.fangjian@huawei.com Cc: Sven Van Asbroeck thesven73@gmail.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Tested-by: Xin Hao xhao@linux.alibaba.com Link: https://lore.kernel.org/r/20210511140912.30757-1-andriy.shevchenko@linux.int... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 5495138c257e..6ae7418f648c 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -823,16 +823,29 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) { if (!(spi->mode & SPI_NO_CS)) { - if (spi->cs_gpiod) - /* polarity handled by gpiolib */ - gpiod_set_value_cansleep(spi->cs_gpiod, - enable1); - else + if (spi->cs_gpiod) { + /* + * Historically ACPI has no means of the GPIO polarity and + * thus the SPISerialBus() resource defines it on the per-chip + * basis. In order to avoid a chain of negations, the GPIO + * polarity is considered being Active High. Even for the cases + * when _DSD() is involved (in the updated versions of ACPI) + * the GPIO CS polarity must be defined Active High to avoid + * ambiguity. That's why we use enable, that takes SPI_CS_HIGH + * into account. + */ + if (has_acpi_companion(&spi->dev)) + gpiod_set_value_cansleep(spi->cs_gpiod, !enable); + else + /* Polarity handled by GPIO library */ + gpiod_set_value_cansleep(spi->cs_gpiod, enable1); + } else { /* * invert the enable line, as active low is * default for SPI. */ gpio_set_value_cansleep(spi->cs_gpio, !enable); + } } /* Some SPI masters need both GPIO CS & slave_select */ if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&