Openwrt/target/linux/bcm27xx/patches-5.4/950-0646-spi-Force-CS_HIGH-if-GPIO-descriptors-are-used.patch
Álvaro Fernández Rojas f07e572f64 bcm27xx: import latest patches from the RPi foundation
bcm2708: boot tested on RPi B+ v1.2
bcm2709: boot tested on RPi 3B v1.2 and RPi 4B v1.1 4G
bcm2710: boot tested on RPi 3B v1.2
bcm2711: boot tested on RPi 4B v1.1 4G

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2021-02-18 23:42:32 +01:00

49 lines
1.7 KiB
Diff

From 5f2eface651ba5da9caaa84ccca14b9202ba6202 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>
---
drivers/spi/spi.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3115,6 +3115,7 @@ 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;
@@ -3132,6 +3133,14 @@ 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_warn(&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,