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spi: Fix incorrect cs_setup delay handling 

Move the cs_setup delay to the end of spi_set_cs.

From include/linux/spi/spi.h:

 * @cs_setup: delay to be introduced by the controller after CS is
   asserted

The cs_setup delay needs to happen *after* CS is asserted, that is, at
the end of spi_set_cs, not at the beginning. Otherwise we're just
delaying before the SPI transaction starts at all, which isn't very
useful.

No drivers use this right now, but that is likely to change soon with an
upcoming Apple SPI HID transport driver.

Fixes: 25093bdeb6 ("spi: implement SW control for CS times")
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20211210170534.177139-1-marcan@marcan.st
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Hector Martin 2021-12-11 02:05:34 +09:00 committed by Mark Brown
parent e9d7c323cf
commit 95c0724739
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 6 additions and 7 deletions
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13
drivers/spi/spi.c
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@ -944,12 +944,9 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
spi->controller->last_cs_enable = enable; spi->controller->last_cs_enable = enable;
spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH; spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) || if ((spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
!spi->controller->set_cs_timing) { !spi->controller->set_cs_timing) && !activate) {
if (activate) spi_delay_exec(&spi->cs_hold, NULL);
spi_delay_exec(&spi->cs_setup, NULL);
else
spi_delay_exec(&spi->cs_hold, NULL);
} }
if (spi->mode & SPI_CS_HIGH) if (spi->mode & SPI_CS_HIGH)
@ -991,7 +988,9 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) || if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
!spi->controller->set_cs_timing) { !spi->controller->set_cs_timing) {
if (!activate) if (activate)
spi_delay_exec(&spi->cs_setup, NULL);
else
spi_delay_exec(&spi->cs_inactive, NULL); spi_delay_exec(&spi->cs_inactive, NULL);
} }
} }