1 From 5f2eface651ba5da9caaa84ccca14b9202ba6202 Mon Sep 17 00:00:00 2001
2 From: Phil Elwell <phil@raspberrypi.com>
3 Date: Fri, 17 Apr 2020 10:46:19 +0100
4 Subject: [PATCH] spi: Force CS_HIGH if GPIO descriptors are used
6 Commit f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
7 amended of_spi_parse_dt() to always set SPI_CS_HIGH for SPI slaves whose
8 Chip Select is defined by a "cs-gpios" devicetree property.
10 This change breaks drivers whose probe functions set the mode field of
11 the spi_device because in doing so they clear the SPI_CS_HIGH flag.
13 Fix by setting SPI_CS_HIGH in spi_setup (under the same conditions as
14 in of_spi_parse_dt()).
16 See also: 83b2a8fe43bd ("spi: spidev: Fix CS polarity if GPIO descriptors are used")
18 Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
19 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
21 drivers/spi/spi.c | 9 +++++++++
22 1 file changed, 9 insertions(+)
24 --- a/drivers/spi/spi.c
25 +++ b/drivers/spi/spi.c
26 @@ -3058,6 +3058,7 @@ static int __spi_validate_bits_per_word(
28 int spi_setup(struct spi_device *spi)
30 + struct spi_controller *ctlr = spi->controller;
31 unsigned bad_bits, ugly_bits;
34 @@ -3075,6 +3076,14 @@ int spi_setup(struct spi_device *spi)
35 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
36 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
39 + if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods &&
40 + ctlr->cs_gpiods[spi->chip_select] && !(spi->mode & SPI_CS_HIGH)) {
42 + "setup: forcing CS_HIGH (use_gpio_descriptors)\n");
43 + spi->mode |= SPI_CS_HIGH;
46 /* help drivers fail *cleanly* when they need options
47 * that aren't supported with their current controller
48 * SPI_CS_WORD has a fallback software implementation,