spi: spi-gpio: Add checks for the dt properties

The bindings assumed that the gpios properties were always there, which
made the NO_TX and NO_RX mode not usable from device tree. Add extra
checks to make sure that the driver can work if either MOSI or MISO is
not used.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 20 insertions, 3 deletions

diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index c7cf0b7a069b..9ddef55a7165 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -365,9 +365,26 @@ static int spi_gpio_probe_dt(struct platform_device *pdev)
         if (!pdata)
                 return -ENOMEM;
 
-        pdata->sck = of_get_named_gpio(np, "gpio-sck", 0);
-        pdata->miso = of_get_named_gpio(np, "gpio-miso", 0);
-        pdata->mosi = of_get_named_gpio(np, "gpio-mosi", 0);
+        ret = of_get_named_gpio(np, "gpio-sck", 0);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "gpio-sck property not found\n");
+                goto error_free;
+        }
+        pdata->sck = ret;
+
+        ret = of_get_named_gpio(np, "gpio-miso", 0);
+        if (ret < 0) {
+                dev_info(&pdev->dev, "gpio-miso property not found, switching to no-rx mode\n");
+                pdata->miso = SPI_GPIO_NO_MISO;
+        } else
+                pdata->miso = ret;
+
+        ret = of_get_named_gpio(np, "gpio-mosi", 0);
+        if (ret < 0) {
+                dev_info(&pdev->dev, "gpio-mosi property not found, switching to no-tx mode\n");
+                pdata->mosi = SPI_GPIO_NO_MOSI;
+        } else
+                pdata->mosi = ret;
 
         ret = of_property_read_u32(np, "num-chipselects", &tmp);
         if (ret < 0) {