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authorMark Brown <broonie@kernel.org>2018-12-04 17:31:49 +0000
committerMark Brown <broonie@kernel.org>2018-12-04 17:31:49 +0000
commitae218f7847fcf32e75ba82b1f3ab01fe53731d7a (patch)
treeaeb782a46c38b1fa561aef92c65125bf29cbafa6 /drivers/spi
parent32215a6c6beb8dcda4bb0759b04ce3c30927963b (diff)
parent5132b3d283710d196cd8af99b5585507e8b30709 (diff)
Merge branch 'topic/3wire-gpio' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi into spi-4.21 mode conflict
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-gpio.c24
1 files changed, 21 insertions, 3 deletions
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 45973ee3ae11..a4aee26028cd 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -256,11 +256,29 @@ static int spi_gpio_setup(struct spi_device *spi)
static int spi_gpio_set_direction(struct spi_device *spi, bool output)
{
struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+ int ret;
if (output)
return gpiod_direction_output(spi_gpio->mosi, 1);
- else
- return gpiod_direction_input(spi_gpio->mosi);
+
+ ret = gpiod_direction_input(spi_gpio->mosi);
+ if (ret)
+ return ret;
+ /*
+ * Send a turnaround high impedance cycle when switching
+ * from output to input. Theoretically there should be
+ * a clock delay here, but as has been noted above, the
+ * nsec delay function for bit-banged GPIO is simply
+ * {} because bit-banging just doesn't get fast enough
+ * anyway.
+ */
+ if (spi->mode & SPI_3WIRE_HIZ) {
+ gpiod_set_value_cansleep(spi_gpio->sck,
+ !(spi->mode & SPI_CPOL));
+ gpiod_set_value_cansleep(spi_gpio->sck,
+ !!(spi->mode & SPI_CPOL));
+ }
+ return 0;
}
static void spi_gpio_cleanup(struct spi_device *spi)
@@ -410,7 +428,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
return status;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
- master->mode_bits = SPI_3WIRE | SPI_CPHA | SPI_CPOL;
+ master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL;
master->flags = master_flags;
master->bus_num = pdev->id;
/* The master needs to think there is a chipselect even if not connected */

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