[PATCH RFC] spi/gpio: start with CS non-active
From: Uwe Kleine-König <hidden>
Date: 2012-02-09 21:21:45
Subsystem:
spi subsystem, the rest · Maintainers:
Mark Brown, Linus Torvalds
The chip select line was configured as output with the initial value being active explicitly. It was later deasserted during spi_bitbang_setup() without any clock activity in between. So it makes no sense to activate the device at all and the chip select line can better start non-active. Signed-off-by: Uwe Kleine-König <redacted> --- Hello, I'm not sure if an active chip select line without any clock activity can confuse a device. If so, this patch might qualify as fix. But with my limited knowledge about spi it's also possible that I just miss why the active chip select is important. For the devices I have it doesn't seem to make a difference. Best regards Uwe drivers/spi/spi-gpio.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 0094c64..0b56cfc 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c@@ -235,7 +235,8 @@ static int spi_gpio_setup(struct spi_device *spi) status = gpio_request(cs, dev_name(&spi->dev)); if (status) return status; - status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH); + status = gpio_direction_output(cs, + !(spi->mode & SPI_CS_HIGH)); } } if (!status)
--
1.7.9
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