korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-03 09:04:21 +08:00
Code Issues Packages Projects Releases Wiki Activity

spi: orion: Handle GPIO chip-selects

Browse Source 
Some hardware designs use GPIOs to add (or supplement) the SPI
chip-select so that more than one SPI slave device can be used.

For this to work with the spi-orion driver the SPI_MASTER_GPIO_SS flag
needs to be set (because the other outputs are gated internally by the
CS) and the correct chip-select (in this case CS0) needs to be driven by
the controller.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Chris Packham 2017-05-23 16:03:21 +12:00 committed by Mark Brown
parent 2ea659a9ef
commit b28b9149b3
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/spi/spi-orion.c
View File

@ -22,6 +22,7 @@
#include <linux/of_device.h>
#include <linux/clk.h>
#include <linux/sizes.h>
#include <linux/gpio.h>
#include <asm/unaligned.h>
#define DRIVER_NAME "orion_spi"
@ -320,12 +321,18 @@ orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
static void orion_spi_set_cs(struct spi_device *spi, bool enable)
{
struct orion_spi *orion_spi;
int cs;
if (gpio_is_valid(spi->cs_gpio))
cs = 0;
else
cs = spi->chip_select;
orion_spi = spi_master_get_devdata(spi->master);
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
ORION_SPI_CS(spi->chip_select));
ORION_SPI_CS(cs));
/* Chip select logic is inverted from spi_set_cs */
if (!enable)
@ -606,6 +613,7 @@ static int orion_spi_probe(struct platform_device *pdev)
master->setup = orion_spi_setup;
master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
master->auto_runtime_pm = true;
master->flags = SPI_MASTER_GPIO_SS;
platform_set_drvdata(pdev, master);