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 /drivers/spi/spi.c | |
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 'drivers/spi/spi.c')
-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 |