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spi: Force CS_HIGH if GPIO descriptors are used

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Commit f3186dd876 ("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: 83b2a8fe43 ("spi: spidev: Fix CS polarity if GPIO descriptors are used")

Fixes: f3186dd876 ("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>
This commit is contained in:
Phil Elwell
2020-04-17 10:46:19 +01:00
committed by Dom Cobley
parent 5c3ab8b241
commit 04cdccba0f
1 changed files with 9 additions and 0 deletions
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9
drivers/spi/spi.c
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@@ -3882,6 +3882,7 @@ static int spi_set_cs_timing(struct spi_device *spi)
*/
int spi_setup(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
unsigned bad_bits, ugly_bits;
int status;
@@ -3908,6 +3909,14 @@ int spi_setup(struct spi_device *spi)
"setup: MOSI configured to idle low and high at the same time.\n");
return -EINVAL;
}
if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods &&
ctlr->cs_gpiods[spi->chip_select[0]] && !(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.