bcm27xx: add linux 5.4 support

Tested on bcm2710 (Raspberry Pi 3B).

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

1 files changed, 80 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.4/950-0134-spi-spi-bcm2835-Re-enable-HW-CS.patch b/target/linux/bcm27xx/patches-5.4/950-0134-spi-spi-bcm2835-Re-enable-HW-CS.patch
new file mode 100644
index 0000000000..d8cac64e81
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0134-spi-spi-bcm2835-Re-enable-HW-CS.patch
@@ -0,0 +1,80 @@
+From 33b150a792ccde6eded4240dea0e3ec784b07d7c Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Tue, 15 Jan 2019 12:39:50 +0000
+Subject: [PATCH] spi: spi-bcm2835: Re-enable HW CS
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/spi/spi-bcm2835.c | 53 +++++++++++++++++++++++++++++++++++++--
+ 1 file changed, 51 insertions(+), 2 deletions(-)
+
+--- a/drivers/spi/spi-bcm2835.c
++++ b/drivers/spi/spi-bcm2835.c
+@@ -1169,9 +1169,57 @@ static void bcm2835_spi_handle_err(struc
+ 	bcm2835_spi_reset_hw(ctlr);
+ }
+ 
+-static int chip_match_name(struct gpio_chip *chip, void *data)
++static void bcm2835_spi_set_cs(struct spi_device *spi, bool gpio_level)
+ {
+-	return !strcmp(chip->label, data);
++	/*
++	 * we can assume that we are "native" as per spi_set_cs
++	 *   calling us ONLY when cs_gpio is not set
++	 * we can also assume that we are CS < 3 as per bcm2835_spi_setup
++	 *   we would not get called because of error handling there.
++	 * the level passed is the electrical level not enabled/disabled
++	 *   so it has to get translated back to enable/disable
++	 *   see spi_set_cs in spi.c for the implementation
++	 */
++
++	struct spi_master *master = spi->master;
++	struct bcm2835_spi *bs = spi_master_get_devdata(master);
++	u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
++	bool enable;
++
++	/* calculate the enable flag from the passed gpio_level */
++	enable = (spi->mode & SPI_CS_HIGH) ? gpio_level : !gpio_level;
++
++	/* set flags for "reverse" polarity in the registers */
++	if (spi->mode & SPI_CS_HIGH) {
++		/* set the correct CS-bits */
++		cs |= BCM2835_SPI_CS_CSPOL;
++		cs |= BCM2835_SPI_CS_CSPOL0 << spi->chip_select;
++	} else {
++		/* clean the CS-bits */
++		cs &= ~BCM2835_SPI_CS_CSPOL;
++		cs &= ~(BCM2835_SPI_CS_CSPOL0 << spi->chip_select);
++	}
++
++	/* select the correct chip_select depending on disabled/enabled */
++	if (enable) {
++		/* set cs correctly */
++		if (spi->mode & SPI_NO_CS) {
++			/* use the "undefined" chip-select */
++			cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
++		} else {
++			/* set the chip select */
++			cs &= ~(BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01);
++			cs |= spi->chip_select;
++		}
++	} else {
++		/* disable CSPOL which puts HW-CS into deselected state */
++		cs &= ~BCM2835_SPI_CS_CSPOL;
++		/* use the "undefined" chip-select as precaution */
++		cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
++	}
++
++	/* finally set the calculated flags in SPI_CS */
++	bcm2835_wr(bs, BCM2835_SPI_CS, cs);
+ }
+ 
+ static int bcm2835_spi_setup(struct spi_device *spi)
+@@ -1289,6 +1337,7 @@ static int bcm2835_spi_probe(struct plat
+ 	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
+ 	ctlr->num_chipselect = BCM2835_SPI_NUM_CS;
+ 	ctlr->setup = bcm2835_spi_setup;
++	ctlr->set_cs = bcm2835_spi_set_cs;
+ 	ctlr->transfer_one = bcm2835_spi_transfer_one;
+ 	ctlr->handle_err = bcm2835_spi_handle_err;
+ 	ctlr->prepare_message = bcm2835_spi_prepare_message;