summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpiolib-of.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/gpio/gpiolib-of.c')
-rw-r--r--drivers/gpio/gpiolib-of.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 4650bf830d6b..a6c67c6b4680 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -22,6 +22,7 @@
#include <linux/of_gpio.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
+#include <linux/gpio/machine.h>
#include "gpiolib.h"
@@ -118,6 +119,114 @@ int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
EXPORT_SYMBOL(of_get_named_gpio_flags);
/**
+ * of_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API
+ * @np: device node to get GPIO from
+ * @name: GPIO line name
+ * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
+ * of_get_gpio_hog()
+ * @dflags: gpiod_flags - optional GPIO initialization flags
+ *
+ * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
+ * value on the error condition.
+ */
+static struct gpio_desc *of_get_gpio_hog(struct device_node *np,
+ const char **name,
+ enum gpio_lookup_flags *lflags,
+ enum gpiod_flags *dflags)
+{
+ struct device_node *chip_np;
+ enum of_gpio_flags xlate_flags;
+ struct gpio_desc *desc;
+ struct gg_data gg_data = {
+ .flags = &xlate_flags,
+ };
+ u32 tmp;
+ int i, ret;
+
+ chip_np = np->parent;
+ if (!chip_np)
+ return ERR_PTR(-EINVAL);
+
+ xlate_flags = 0;
+ *lflags = 0;
+ *dflags = 0;
+
+ ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (tmp > MAX_PHANDLE_ARGS)
+ return ERR_PTR(-EINVAL);
+
+ gg_data.gpiospec.args_count = tmp;
+ gg_data.gpiospec.np = chip_np;
+ for (i = 0; i < tmp; i++) {
+ ret = of_property_read_u32_index(np, "gpios", i,
+ &gg_data.gpiospec.args[i]);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+
+ gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
+ if (!gg_data.out_gpio) {
+ if (np->parent == np)
+ return ERR_PTR(-ENXIO);
+ else
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (xlate_flags & OF_GPIO_ACTIVE_LOW)
+ *lflags |= GPIO_ACTIVE_LOW;
+
+ if (of_property_read_bool(np, "input"))
+ *dflags |= GPIOD_IN;
+ else if (of_property_read_bool(np, "output-low"))
+ *dflags |= GPIOD_OUT_LOW;
+ else if (of_property_read_bool(np, "output-high"))
+ *dflags |= GPIOD_OUT_HIGH;
+ else {
+ pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
+ desc_to_gpio(gg_data.out_gpio), np->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (name && of_property_read_string(np, "line-name", name))
+ *name = np->name;
+
+ desc = gg_data.out_gpio;
+
+ return desc;
+}
+
+/**
+ * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested
+ * @chip: gpio chip to act on
+ *
+ * This is only used by of_gpiochip_add to request/set GPIO initial
+ * configuration.
+ */
+static void of_gpiochip_scan_hogs(struct gpio_chip *chip)
+{
+ struct gpio_desc *desc = NULL;
+ struct device_node *np;
+ const char *name;
+ enum gpio_lookup_flags lflags;
+ enum gpiod_flags dflags;
+
+ for_each_child_of_node(chip->of_node, np) {
+ if (!of_property_read_bool(np, "gpio-hog"))
+ continue;
+
+ desc = of_get_gpio_hog(np, &name, &lflags, &dflags);
+ if (IS_ERR(desc))
+ continue;
+
+ if (gpiod_hog(desc, name, lflags, dflags))
+ continue;
+ }
+}
+
+/**
* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
* @gc: pointer to the gpio_chip structure
* @np: device node of the GPIO chip
@@ -326,6 +435,8 @@ void of_gpiochip_add(struct gpio_chip *chip)
of_gpiochip_add_pin_range(chip);
of_node_get(chip->of_node);
+
+ of_gpiochip_scan_hogs(chip);
}
void of_gpiochip_remove(struct gpio_chip *chip)