bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0696-spi-gpio-Add-sck-idle-input-property.patch b/target/linux/bcm27xx/patches-5.15/950-0696-spi-gpio-Add-sck-idle-input-property.patch
new file mode 100644
index 0000000000..6b359c4bb8
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0696-spi-gpio-Add-sck-idle-input-property.patch
@@ -0,0 +1,57 @@
+From c979072887ef70aab2ab6e71544853df71017925 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Wed, 12 Jan 2022 08:23:28 +0000
+Subject: [PATCH] spi: gpio: Add sck-idle-input property
+
+The sck-idle-input property indicates that the spi-gpio driver should
+return the SCK line to an input when the chip select signals are
+inactive.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/spi/spi-gpio.c | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+--- a/drivers/spi/spi-gpio.c
++++ b/drivers/spi/spi-gpio.c
+@@ -35,6 +35,7 @@ struct spi_gpio {
+ 	struct gpio_desc		*sck;
+ 	struct gpio_desc		*miso;
+ 	struct gpio_desc		*mosi;
++	bool				sck_idle_input;
+ 	struct gpio_desc		**cs_gpios;
+ };
+ 
+@@ -201,8 +202,12 @@ static void spi_gpio_chipselect(struct s
+ 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+ 
+ 	/* set initial clock line level */
+-	if (is_active)
+-		gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);
++	if (is_active) {
++		if (spi_gpio->sck_idle_input)
++			gpiod_direction_output(spi_gpio->sck, spi->mode & SPI_CPOL);
++		else
++			gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);
++	}
+ 
+ 	/* Drive chip select line, if we have one */
+ 	if (spi_gpio->cs_gpios) {
+@@ -211,6 +216,9 @@ static void spi_gpio_chipselect(struct s
+ 		/* SPI chip selects are normally active-low */
+ 		gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
+ 	}
++
++	if (spi_gpio->sck_idle_input && !is_active)
++		gpiod_direction_input(spi_gpio->sck);
+ }
+ 
+ static int spi_gpio_setup(struct spi_device *spi)
+@@ -289,6 +297,7 @@ static int spi_gpio_request(struct devic
+ 	if (IS_ERR(spi_gpio->miso))
+ 		return PTR_ERR(spi_gpio->miso);
+ 
++	spi_gpio->sck_idle_input = device_property_read_bool(dev, "sck-idle-input");
+ 	spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);
+ 	return PTR_ERR_OR_ZERO(spi_gpio->sck);
+ }