Messages in this thread Patch in this message | | | From | Linus Walleij <> | Subject | [PATCH] mfd: motorola-cpcap: Do not hardcode SPI mode flags | Date | Thu, 5 Dec 2019 00:19:31 +0100 |
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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/motorola-cpcap.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/mfd/motorola-cpcap.c b/drivers/mfd/motorola-cpcap.c index 52f38e57cdc1..a3bc61b8008c 100644 --- a/drivers/mfd/motorola-cpcap.c +++ b/drivers/mfd/motorola-cpcap.c @@ -279,7 +279,13 @@ static int cpcap_probe(struct spi_device *spi) spi_set_drvdata(spi, cpcap); spi->bits_per_word = 16; - spi->mode = SPI_MODE_0 | SPI_CS_HIGH; + spi->mode |= SPI_MODE_0; + /* + * Active high should be defined as "inverse polarity" as GPIO-based + * chip selects can be logically active high but inverted by the GPIO + * library. + */ + spi->mode ^= SPI_CS_HIGH; ret = spi_setup(spi); if (ret) -- 2.23.0
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