From: Alexander Sverdlin alexander.sverdlin@siemens.com
[ Upstream commit 7dbfa445ff7393d1c4c066c1727c9e0af1251958 ]
Commit f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs") has changed the user-space interface so that bogus SPI_CS_HIGH started to appear in the mask returned by SPI_IOC_RD_MODE even for active-low CS pins. Commit 138c9c32f090 ("spi: spidev: Fix CS polarity if GPIO descriptors are used") fixed only SPI_IOC_WR_MODE part of the problem. Let's fix SPI_IOC_RD_MODE symmetrically.
Test case:
#include <sys/ioctl.h> #include <fcntl.h> #include <linux/spi/spidev.h>
int main(int argc, char **argv) { char modew = SPI_CPHA; char moder; int f = open("/dev/spidev0.0", O_RDWR);
if (f < 0) return 1;
ioctl(f, SPI_IOC_WR_MODE, &modew); ioctl(f, SPI_IOC_RD_MODE, &moder);
return moder == modew ? 0 : 2; }
Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs") Signed-off-by: Alexander Sverdlin alexander.sverdlin@siemens.com Link: https://lore.kernel.org/r/20221130162927.539512-1-alexander.sverdlin@siemens... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spidev.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index b2775d82d2d7..6313e7d0cdf8 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -377,12 +377,23 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) switch (cmd) { /* read requests */ case SPI_IOC_RD_MODE: - retval = put_user(spi->mode & SPI_MODE_MASK, - (__u8 __user *)arg); - break; case SPI_IOC_RD_MODE32: - retval = put_user(spi->mode & SPI_MODE_MASK, - (__u32 __user *)arg); + tmp = spi->mode; + + { + struct spi_controller *ctlr = spi->controller; + + if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && + ctlr->cs_gpiods[spi->chip_select]) + tmp &= ~SPI_CS_HIGH; + } + + if (cmd == SPI_IOC_RD_MODE) + retval = put_user(tmp & SPI_MODE_MASK, + (__u8 __user *)arg); + else + retval = put_user(tmp & SPI_MODE_MASK, + (__u32 __user *)arg); break; case SPI_IOC_RD_LSB_FIRST: retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,