diff options
| author | Andreas Färber <afaerber@suse.de> | 2022-02-19 16:15:48 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2022-02-22 14:56:41 +0300 |
| commit | 1847e3046c528bd85bd51e2860f4139bd9052d6c (patch) | |
| tree | b5384060b3dec3f43071d118d36185cf6f3fe9e5 /drivers/spi/spi-gpio.c | |
| parent | 5741150c808b2bbeb1017609f3029daf6651b7d5 (diff) | |
| download | linux-1847e3046c528bd85bd51e2860f4139bd9052d6c.tar.xz | |
spi: gpio: Implement LSB First bitbang support
Add support for slave DT property spi-lsb-first, i.e., SPI_LSB_FIRST mode.
Duplicate the inline helpers bitbang_txrx_be_cpha{0,1} as LE versions.
Conditionally call them from all the spi-gpio txrx_word callbacks.
Some alternatives to this implementation approach were discussed back
then [0], but eventually it was considered reasonable.
[0] https://lore.kernel.org/linux-arm-kernel/20191212033952.5967-8-afaerber@suse.de/
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Link: https://lore.kernel.org/r/feac3377-4ad1-77d8-9a18-3588d80fb909@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-gpio.c')
| -rw-r--r-- | drivers/spi/spi-gpio.c | 42 |
1 files changed, 33 insertions, 9 deletions
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index 0584f4d2fde2..4b12c4964a66 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -135,25 +135,37 @@ static inline int getmiso(const struct spi_device *spi) static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { - return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits); + else + return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); } static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { - return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits); + else + return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); } static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { - return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits); + else + return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); } static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { - return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits); + else + return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); } /* @@ -170,28 +182,40 @@ static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { flags = spi->master->flags; - return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits); + else + return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); } static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { flags = spi->master->flags; - return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits); + else + return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); } static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { flags = spi->master->flags; - return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits); + else + return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); } static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { flags = spi->master->flags; - return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); + if (unlikely(spi->mode & SPI_LSB_FIRST)) + return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits); + else + return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); } /*----------------------------------------------------------------------*/ @@ -378,7 +402,7 @@ static int spi_gpio_probe(struct platform_device *pdev) master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL | - SPI_CS_HIGH; + SPI_CS_HIGH | SPI_LSB_FIRST; if (!spi_gpio->mosi) { /* HW configuration without MOSI pin * |