raspi/linux
1
0
Fork 1
mirror of https://github.com/raspberrypi/linux.git synced 2025-12-06 01:49:46 +00:00
Code Issues Projects Releases Wiki Activity

spi: spi-bcm2835: Re-enable HW CS

Browse Source 
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
This commit is contained in:
Phil Elwell
2019-01-15 12:39:50 +00:00
committed by popcornmix
parent 233cffde67
commit f75cc2b7ab
1 changed files with 51 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
drivers/spi/spi-bcm2835.c
View File

@@ -934,9 +934,57 @@ static void bcm2835_spi_handle_err(struct spi_controller *ctlr,
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)
@@ -1003,6 +1051,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
ctlr->num_chipselect = 3;
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;