diff options
| author | Thor Thayer <tthayer@opensource.altera.com> | 2016-10-10 09:25:24 -0500 |
|---|---|---|
| committer | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2019-04-30 20:01:56 +0200 |
| commit | 51fdc026c6fecf81c8a85edef4e954a05e67b5c8 (patch) | |
| tree | 2a8d78084968ed401201aaf95fd3d5c0ba1b23e3 /include | |
| parent | 05a78cee0beea6ab8d90058fc65cf2af3bbf4a6b (diff) | |
spi: Add Flag to Enable Slave Select with GPIO Chip Select.
Some SPI masters require slave selection before the transfer
can begin [1]. The SPI framework currently selects the chip using
either 1) the internal CS mechanism or 2) the GPIO CS, but not both.
This patch adds a new master->flags define to indicate both the GPIO
CS and the internal chip select mechanism should be used.
Tested On:
Altera CycloneV development kit
Compile tested for build errors on x86_64 (allyesconfigs)
[1] DesignWare dw_apb_ssi Databook, Version 3.20a (page 39)
Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/spi/spi.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index cce80e6dc7d1..8bee6e2f0b57 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -424,6 +424,7 @@ struct spi_master { #define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ #define SPI_MASTER_MUST_RX BIT(3) /* requires rx */ #define SPI_MASTER_MUST_TX BIT(4) /* requires tx */ +#define SPI_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */ /* lock and mutex for SPI bus locking */ spinlock_t bus_lock_spinlock; |