diff options
| author | Thor Thayer <tthayer@opensource.altera.com> | 2016-10-10 09:25:24 -0500 |
|---|---|---|
| committer | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2019-10-02 00:39:21 +0200 |
| commit | fcf547a7c92cccd99283738071ef1a3ece1a25b2 (patch) | |
| tree | df8172a145035ed7a66db9c32ef44615d4f9f975 /drivers | |
| parent | bcab1d704b1f5d728d5d88620643bd4fac9fbc8b (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 'drivers')
| -rw-r--r-- | drivers/spi/spi.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 04fd651f9e3e..b956453b8806 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -673,10 +673,15 @@ static void spi_set_cs(struct spi_device *spi, bool enable) if (spi->mode & SPI_CS_HIGH) enable = !enable; - if (gpio_is_valid(spi->cs_gpio)) + if (gpio_is_valid(spi->cs_gpio)) { gpio_set_value(spi->cs_gpio, !enable); - else if (spi->master->set_cs) + /* Some SPI masters need both GPIO CS & slave_select */ + if ((spi->master->flags & SPI_MASTER_GPIO_SS) && + spi->master->set_cs) + spi->master->set_cs(spi, !enable); + } else if (spi->master->set_cs) { spi->master->set_cs(spi, !enable); + } } #ifdef CONFIG_HAS_DMA |