spi: Force CS_HIGH if GPIO descriptors are used

Commit f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
amended of_spi_parse_dt() to always set SPI_CS_HIGH for SPI slaves whose
Chip Select is defined by a "cs-gpios" devicetree property.

This change breaks drivers whose probe functions set the mode field of
the spi_device because in doing so they clear the SPI_CS_HIGH flag.

Fix by setting SPI_CS_HIGH in spi_setup (under the same conditions as
in of_spi_parse_dt()).

See also: 83b2a8fe43bd ("spi: spidev: Fix CS polarity if GPIO descriptors are used")

Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
SQUASH: spi: Demote SPI_CS_HIGH warning to KERN_DEBUG

This warning is unavoidable from a client's perspective and
doesn't indicate anything wrong (just surprising).

SQUASH with "spi: use_gpio_descriptor fixup moved to spi_setup"

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a42b9e8..047b382 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3465,6 +3465,7 @@ static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
  */
 int spi_setup(struct spi_device *spi)
 {
+       struct spi_controller *ctlr = spi->controller;
        unsigned        bad_bits, ugly_bits;
        int             status;
 
@@ -3486,6 +3487,14 @@ int spi_setup(struct spi_device *spi)
                (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
                 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
                return -EINVAL;
+
+       if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods &&
+           ctlr->cs_gpiods[spi->chip_select] && !(spi->mode & SPI_CS_HIGH)) {
+               dev_dbg(&spi->dev,
+                       "setup: forcing CS_HIGH (use_gpio_descriptors)\n");
+               spi->mode |= SPI_CS_HIGH;
+       }
+
        /* help drivers fail *cleanly* when they need options
         * that aren't supported with their current controller
         * SPI_CS_WORD has a fallback software implementation,