| Message ID | 20191204152715.12553-1-linus.walleij@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | mfd: mc13xxx-spi: Do not hardcode SPI mode flags | expand |
diff --git a/drivers/mfd/mc13xxx-spi.c b/drivers/mfd/mc13xxx-spi.c index 286ddcf5ddc6..9885e5f8210a 100644 --- a/drivers/mfd/mc13xxx-spi.c +++ b/drivers/mfd/mc13xxx-spi.c @@ -134,7 +134,13 @@ static int mc13xxx_spi_probe(struct spi_device *spi) dev_set_drvdata(&spi->dev, mc13xxx); - spi->mode = SPI_MODE_0 | SPI_CS_HIGH; + spi->mode |= SPI_MODE_0; + /* + * We want the inverse of what is set in the SPI core, if this + * is accomplished with a GPIO line then inversion semantics may + * be handled in the GPIO library. + */ + spi->mode ^= SPI_CS_HIGH; mc13xxx->irq = spi->irq;
The current use of mode flags to us SPI_MODE_0 and SPI_CS_HIGH is fragile: it overwrites anything already assigned by the SPI core. Change it thusly: - Just |= the SPI_MODE_0 so we keep other flags - Assign ^= SPI_CS_HIGH since we might be active high already, and that is usually the case with GPIOs used for chip select, even if they are in practice active low. Add a comment clarifying why ^= SPI_CS_HIGH is the right choice here. Reported-by: Mark Brown <broonie@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- drivers/mfd/mc13xxx-spi.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) -- 2.23.0