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authorLorenzo Bianconi <lorenzo.bianconi@redhat.com>2018-07-28 10:19:14 +0200
committerMark Brown <broonie@kernel.org>2018-08-01 14:50:28 +0100
commit4b859db2c60692560afbfef1b030d0ddef57b7ee (patch)
tree70a19c5a126a3eacdfda8f8112a13950cdca0a05
parent304d34360b099020a12af2abb7e1ac506f4ba16d (diff)
spi: spi-gpio: add SPI_3WIRE support
Add SPI_3WIRE support to spi-gpio controller introducing set_line_direction function pointer in spi_bitbang data structure. Spi-gpio controller has been tested using hts221 temp/rh iio sensor running in 3wire mode and lsm6dsm running in 4wire mode Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: Mark Brown <broonie@kernel.org>
-rw-r--r--drivers/spi/spi-bitbang.c16
-rw-r--r--drivers/spi/spi-gpio.c17
-rw-r--r--include/linux/spi/spi_bitbang.h1
3 files changed, 33 insertions, 1 deletions
diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index 76f1b534bdd7..f29176000b8d 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -243,7 +243,23 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct spi_bitbang_cs *cs = spi->controller_state;
unsigned nsecs = cs->nsecs;
+ struct spi_bitbang *bitbang;
+
+ bitbang = spi_master_get_devdata(spi->master);
+ if (bitbang->set_line_direction) {
+ int err;
+ err = bitbang->set_line_direction(spi, !!(t->tx_buf));
+ if (err < 0)
+ return err;
+ }
+
+ if (spi->mode & SPI_3WIRE) {
+ unsigned flags;
+
+ flags = t->tx_buf ? SPI_MASTER_NO_RX : SPI_MASTER_NO_TX;
+ return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, flags);
+ }
return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, 0);
}
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index be68298cbd9c..0626e6e3ea0c 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -121,7 +121,10 @@ static inline int getmiso(const struct spi_device *spi)
{
struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
- return !!gpiod_get_value_cansleep(spi_gpio->miso);
+ if (spi->mode & SPI_3WIRE)
+ return !!gpiod_get_value_cansleep(spi_gpio->mosi);
+ else
+ return !!gpiod_get_value_cansleep(spi_gpio->miso);
}
/*
@@ -250,6 +253,16 @@ static int spi_gpio_setup(struct spi_device *spi)
return status;
}
+static int spi_gpio_set_direction(struct spi_device *spi, bool output)
+{
+ struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+
+ if (output)
+ return gpiod_direction_output(spi_gpio->mosi, 1);
+ else
+ return gpiod_direction_input(spi_gpio->mosi);
+}
+
static void spi_gpio_cleanup(struct spi_device *spi)
{
spi_bitbang_cleanup(spi);
@@ -395,6 +408,7 @@ 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->flags = master_flags;
master->bus_num = pdev->id;
/* The master needs to think there is a chipselect even if not connected */
@@ -407,6 +421,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
spi_gpio->bitbang.master = master;
spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
+ spi_gpio->bitbang.set_line_direction = spi_gpio_set_direction;
if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) {
spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h
index 5847f00ef9cf..b7e021b274dc 100644
--- a/include/linux/spi/spi_bitbang.h
+++ b/include/linux/spi/spi_bitbang.h
@@ -31,6 +31,7 @@ struct spi_bitbang {
u32 (*txrx_word[4])(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits, unsigned flags);
+ int (*set_line_direction)(struct spi_device *spi, bool output);
};
/* you can call these default bitbang->master methods from your custom