From f58888434d75098a24604ffb5a6a46033704096b Mon Sep 17 00:00:00 2001 From: Alexander Sverdlin Date: Wed, 30 Nov 2022 17:29:27 +0100 Subject: [PATCH] spi: spidev: mask SPI_CS_HIGH in SPI_IOC_RD_MODE [ 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 #include #include 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 Link: https://lore.kernel.org/r/20221130162927.539512-1-alexander.sverdlin@siemens.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- 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 1bd73e322b7b..d233e2424ad1 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -376,12 +376,23 @@ 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,