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>

1 files changed, 59 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.4/950-0789-Revert-spi-spi-bcm2835-Disable-forced-software-CS.patch b/target/linux/bcm27xx/patches-5.4/950-0789-Revert-spi-spi-bcm2835-Disable-forced-software-CS.patch
new file mode 100644
index 0000000000..1479335217
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0789-Revert-spi-spi-bcm2835-Disable-forced-software-CS.patch
@@ -0,0 +1,59 @@
+From 1d78f72cb5a387922870e2a54228be25f84f95f6 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Tue, 16 Jun 2020 10:23:29 +0100
+Subject: [PATCH] Revert "spi: spi-bcm2835: Disable forced software
+ CS"
+
+This reverts commit 2697f0186db346176832b8eb79adaf5c874681e8.
+
+See: https://github.com/raspberrypi/linux/pull/3687
+---
+ drivers/spi/spi-bcm2835.c | 37 +++++++++++++++++++++++++++++++++++++
+ 1 file changed, 37 insertions(+)
+
+--- a/drivers/spi/spi-bcm2835.c
++++ b/drivers/spi/spi-bcm2835.c
+@@ -1235,6 +1235,43 @@ static int bcm2835_spi_setup(struct spi_
+ 		return -EINVAL;
+ 	}
+ 
++	/*
++	 * Translate native CS to GPIO
++	 *
++	 * FIXME: poking around in the gpiolib internals like this is
++	 * not very good practice. Find a way to locate the real problem
++	 * and fix it. Why is the GPIO descriptor in spi->cs_gpiod
++	 * sometimes not assigned correctly? Erroneous device trees?
++	 */
++
++	/* get the gpio chip for the base */
++	chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
++	if (!chip)
++		return 0;
++
++	/*
++	 * Retrieve the corresponding GPIO line used for CS.
++	 * The inversion semantics will be handled by the GPIO core
++	 * code, so we pass GPIOS_OUT_LOW for "unasserted" and
++	 * the correct flag for inversion semantics. The SPI_CS_HIGH
++	 * on spi->mode cannot be checked for polarity in this case
++	 * as the flag use_gpio_descriptors enforces SPI_CS_HIGH.
++	 */
++	if (of_property_read_bool(spi->dev.of_node, "spi-cs-high"))
++		lflags = GPIO_ACTIVE_HIGH;
++	else
++		lflags = GPIO_ACTIVE_LOW;
++	spi->cs_gpiod = gpiochip_request_own_desc(chip, 8 - spi->chip_select,
++						  DRV_NAME,
++						  lflags,
++						  GPIOD_OUT_LOW);
++	if (IS_ERR(spi->cs_gpiod))
++		return PTR_ERR(spi->cs_gpiod);
++
++	/* and set up the "mode" and level */
++	dev_info(&spi->dev, "setting up native-CS%i to use GPIO\n",
++		 spi->chip_select);
++
+ 	return 0;
+ }
+