spi: spi-gpio: Add dt support for a single device with no chip select

In order to describe a single slave device that has no chip select line
the 'num-chipselects' property has to be <0> and the 'cs-gpios' property
doesn't need to be set.

Signed-off-by: Torsten Fleischer <torfl6749@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/Documentation/devicetree/bindings/spi/spi-gpio.txt b/Documentation/devicetree/bindings/spi/spi-gpio.txt
index 8a824be15754a6b488930d60c1c7fba174ef1932..a95603bcf6ffd9bbf99eff8ac2e5e367660e84a7 100644 (file)
--- a/Documentation/devicetree/bindings/spi/spi-gpio.txt
+++ b/Documentation/devicetree/bindings/spi/spi-gpio.txt
@@ -8,8 +8,10 @@ Required properties:
  - gpio-sck: GPIO spec for the SCK line to use
  - gpio-miso: GPIO spec for the MISO line to use
  - gpio-mosi: GPIO spec for the MOSI line to use
- - cs-gpios: GPIOs to use for chipselect lines
- - num-chipselects: number of chipselect lines
+ - cs-gpios: GPIOs to use for chipselect lines.
+             Not needed if num-chipselects = <0>.
+ - num-chipselects: Number of chipselect lines. Should be <0> if a single device
+                    with no chip select is connected.
 
 Example:
 

diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 9f595535cf2742a834527c23caf852e4e1d130c0..f0492c99d1455d6750492242ff45ef5f1bd299e0 100644 (file)
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -413,6 +413,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
        struct spi_gpio_platform_data   *pdata;
        u16 master_flags = 0;
        bool use_of = 0;
+       int num_devices;
 
        status = spi_gpio_probe_dt(pdev);
        if (status < 0)
@@ -422,16 +423,21 @@ static int spi_gpio_probe(struct platform_device *pdev)
 
        pdata = dev_get_platdata(&pdev->dev);
 #ifdef GENERIC_BITBANG
-       if (!pdata || !pdata->num_chipselect)
+       if (!pdata || (!use_of && !pdata->num_chipselect))
                return -ENODEV;
 #endif
 
+       if (use_of && !SPI_N_CHIPSEL)
+               num_devices = 1;
+       else
+               num_devices = SPI_N_CHIPSEL;
+
        status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
        if (status < 0)
                return status;
 
        master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio) +
-                                       (sizeof(int) * SPI_N_CHIPSEL));
+                                       (sizeof(int) * num_devices));
        if (!master) {
                status = -ENOMEM;
                goto gpio_free;
@@ -446,7 +452,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
        master->flags = master_flags;
        master->bus_num = pdev->id;
-       master->num_chipselect = SPI_N_CHIPSEL;
+       master->num_chipselect = num_devices;
        master->setup = spi_gpio_setup;
        master->cleanup = spi_gpio_cleanup;
 #ifdef CONFIG_OF
@@ -461,9 +467,12 @@ static int spi_gpio_probe(struct platform_device *pdev)
                 * property of the node.
                 */
 
-               for (i = 0; i < SPI_N_CHIPSEL; i++)
-                       spi_gpio->cs_gpios[i] =
-                               of_get_named_gpio(np, "cs-gpios", i);
+               if (!SPI_N_CHIPSEL)
+                       spi_gpio->cs_gpios[0] = SPI_GPIO_NO_CHIPSELECT;
+               else
+                       for (i = 0; i < SPI_N_CHIPSEL; i++)
+                               spi_gpio->cs_gpios[i] =
+                                       of_get_named_gpio(np, "cs-gpios", i);
        }
 #endif