By using a gpio_desc and gpiod_set_value() instead of a numeric gpio and
gpio_set_value() the gpio flags are taken into account. This is useful
when using a gpio chip-select to supplement a controllers native
chip-select.
Signed-off-by: Chris Packham <chris.pack...@alliedtelesis.co.nz>
---
(I've included this in this series for context, ultimately it should not be
needed once everything is using gpio_desc)
My specific use-case is I have a board that uses the spi-orion driver but
only has one CS pin available. In order to access two spi slave devices the
board has a 1-of-2 decoder/demultiplexer which is driven via a gpio.
The problem is that for one of the 2 slave devices the gpio level required
is opposite to the chip-select so I can't simply specify "spi-cs-high".
With this change I can flag the gpio as active low and the gpio subsystem
takes care of the additional inversion required.
drivers/spi/spi.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6f87fec409b5..b39c0f9956dd 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -725,7 +725,10 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
enable = !enable;
if (gpio_is_valid(spi->cs_gpio)) {
- gpio_set_value(spi->cs_gpio, !enable);
+ struct gpio_desc *gpio = gpio_to_desc(spi->cs_gpio);
+
+ if (gpio)
+ gpiod_set_value(gpio, !enable);
/* Some SPI masters need both GPIO CS & slave_select */
if ((spi->master->flags & SPI_MASTER_GPIO_SS) &&
spi->master->set_cs)
--
2.13.0
