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- From 51a164a0654895d930acb4e3bd096f7bf54c058b Mon Sep 17 00:00:00 2001
- From: Phil Elwell <[email protected]>
- Date: Fri, 17 Apr 2020 10:46:19 +0100
- Subject: [PATCH] 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 <[email protected]>
- 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 <[email protected]>
- ---
- drivers/spi/spi.c | 9 +++++++++
- 1 file changed, 9 insertions(+)
- --- a/drivers/spi/spi.c
- +++ b/drivers/spi/spi.c
- @@ -3675,6 +3675,7 @@ static int spi_set_cs_timing(struct spi_
- */
- int spi_setup(struct spi_device *spi)
- {
- + struct spi_controller *ctlr = spi->controller;
- unsigned bad_bits, ugly_bits;
- int status = 0;
-
- @@ -3695,6 +3696,14 @@ 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.
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