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From 4b6c8cda93174f36754f549498c133ccaeaa2218 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
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 <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>
---
drivers/spi/spi.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3338,6 +3338,7 @@ static int __spi_validate_bits_per_word(
*/
int spi_setup(struct spi_device *spi)
{
+ struct spi_controller *ctlr = spi->controller;
unsigned bad_bits, ugly_bits;
int status;
@@ -3355,6 +3356,14 @@ 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,
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