diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0134-spi-spi-bcm2835-Re-enable-HW-CS.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0134-spi-spi-bcm2835-Re-enable-HW-CS.patch | 80 |
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; |