spi: spi-gpio: Add DT bindings
This patch adds DT bindings to the spi-gpio driver and some
documentation about how to use it.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index ff7263c..aed1615 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -22,6 +22,8 @@
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
@@ -232,13 +234,27 @@
static int spi_gpio_setup(struct spi_device *spi)
{
- unsigned int cs = (unsigned int) spi->controller_data;
+ unsigned int cs;
int status = 0;
struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);
+ struct device_node *np = spi->master->dev.of_node;
if (spi->bits_per_word > 32)
return -EINVAL;
+ if (np) {
+ /*
+ * In DT environments, the CS GPIOs have already been
+ * initialized from the "cs-gpios" property of the node.
+ */
+ cs = spi_gpio->cs_gpios[spi->chip_select];
+ } else {
+ /*
+ * ... otherwise, take it from spi->controller_data
+ */
+ cs = (unsigned int) spi->controller_data;
+ }
+
if (!spi->controller_state) {
if (cs != SPI_GPIO_NO_CHIPSELECT) {
status = gpio_request(cs, dev_name(&spi->dev));
@@ -250,6 +266,7 @@
}
if (!status) {
status = spi_bitbang_setup(spi);
+ /* in case it was initialized from static board data */
spi_gpio->cs_gpios[spi->chip_select] = cs;
}
@@ -326,6 +343,55 @@
return value;
}
+#ifdef CONFIG_OF
+static struct of_device_id spi_gpio_dt_ids[] = {
+ { .compatible = "spi-gpio" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids);
+
+static int spi_gpio_probe_dt(struct platform_device *pdev)
+{
+ int ret;
+ u32 tmp;
+ struct spi_gpio_platform_data *pdata;
+ struct device_node *np = pdev->dev.of_node;
+ const struct of_device_id *of_id =
+ of_match_device(spi_gpio_dt_ids, &pdev->dev);
+
+ if (!of_id)
+ return 0;
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ 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_property_read_u32(np, "num-chipselects", &tmp);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "num-chipselects property not found\n");
+ goto error_free;
+ }
+
+ pdata->num_chipselect = tmp;
+ pdev->dev.platform_data = pdata;
+
+ return 1;
+
+error_free:
+ devm_kfree(&pdev->dev, pdata);
+ return ret;
+}
+#else
+static inline int spi_probe_dt(struct platform_device *)
+{
+ return 0;
+}
+#endif
+
static int __devinit spi_gpio_probe(struct platform_device *pdev)
{
int status;
@@ -333,6 +399,13 @@
struct spi_gpio *spi_gpio;
struct spi_gpio_platform_data *pdata;
u16 master_flags = 0;
+ bool use_of = 0;
+
+ status = spi_gpio_probe_dt(pdev);
+ if (status < 0)
+ return status;
+ if (status > 0)
+ use_of = 1;
pdata = pdev->dev.platform_data;
#ifdef GENERIC_BITBANG
@@ -362,6 +435,23 @@
master->num_chipselect = SPI_N_CHIPSEL;
master->setup = spi_gpio_setup;
master->cleanup = spi_gpio_cleanup;
+#ifdef CONFIG_OF
+ master->dev.of_node = pdev->dev.of_node;
+
+ if (use_of) {
+ int i;
+ struct device_node *np = pdev->dev.of_node;
+
+ /*
+ * In DT environments, take the CS GPIO from the "cs-gpios"
+ * 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);
+ }
+#endif
spi_gpio->bitbang.master = spi_master_get(master);
spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
@@ -422,8 +512,11 @@
MODULE_ALIAS("platform:" DRIVER_NAME);
static struct platform_driver spi_gpio_driver = {
- .driver.name = DRIVER_NAME,
- .driver.owner = THIS_MODULE,
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(spi_gpio_dt_ids),
+ },
.probe = spi_gpio_probe,
.remove = __devexit_p(spi_gpio_remove),
};