spi: spi-gpio: Add support for MOSI idle state configuration

Implement MOSI idle low and MOSI idle high to better support peripherals
that request specific MOSI behavior.

Acked-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>

Author: machschmitt

drivers/spi/spi-gpio.c

@@ -237,6 +237,14 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
 	}
 }
 
+static void spi_gpio_set_mosi_idle(struct spi_device *spi)
+{
+	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+
+	gpiod_set_value_cansleep(spi_gpio->mosi,
+				 !!(spi->mode & SPI_MOSI_IDLE_HIGH));
+}
+
 static int spi_gpio_setup(struct spi_device *spi)
 {
 	struct gpio_desc	*cs;
@@ -402,7 +410,8 @@ static int spi_gpio_probe(struct platform_device *pdev)
 
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
 	master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |
-			    SPI_CS_HIGH | SPI_LSB_FIRST;
+			  SPI_CS_HIGH | SPI_LSB_FIRST | SPI_MOSI_IDLE_LOW |
+			  SPI_MOSI_IDLE_HIGH;
 	if (!spi_gpio->mosi) {
 		/* HW configuration without MOSI pin
 		 *
@@ -427,6 +436,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
 	master->flags |= SPI_MASTER_GPIO_SS;
 	bb->chipselect = spi_gpio_chipselect;
 	bb->set_line_direction = spi_gpio_set_direction;
+	bb->set_mosi_idle = spi_gpio_set_mosi_idle;
 
 	if (master->flags & SPI_MASTER_NO_TX) {
 		bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;