@@ -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"
@@ -117,6 +118,114 @@ 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
@@ -308,6 +417,8 @@ 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)
@@ -315,6 +315,7 @@ EXPORT_SYMBOL_GPL(gpiochip_add);
/* Forward-declaration */
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
+static void gpiochip_free_hogs(struct gpio_chip *chip);
/**
* gpiochip_remove() - unregister a gpio_chip
@@ -333,6 +334,7 @@ void gpiochip_remove(struct gpio_chip *chip)
acpi_gpiochip_remove(chip);
gpiochip_remove_pin_ranges(chip);
+ gpiochip_free_hogs(chip);
of_gpiochip_remove(chip);
spin_lock_irqsave(&gpio_lock, flags);
@@ -866,6 +868,7 @@ static bool __gpiod_free(struct gpio_desc *desc)
clear_bit(FLAG_REQUESTED, &desc->flags);
clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
+ clear_bit(FLAG_IS_HOGGED, &desc->flags);
ret = true;
}
@@ -1838,6 +1841,47 @@ struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev,
}
EXPORT_SYMBOL_GPL(__gpiod_get_optional);
+
+/**
+ * gpiod_configure_flags - helper function to configure a given GPIO
+ * @desc: gpio whose value will be assigned
+ * @con_id: function within the GPIO consumer
+ * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
+ * of_get_gpio_hog()
+ * @dflags: gpiod_flags - optional GPIO initialization flags
+ *
+ * Return 0 on success, -ENOENT if no GPIO has been assigned to the
+ * requested function and/or index, or another IS_ERR() code if an error
+ * occurred while trying to acquire the GPIO.
+ */
+static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
+ unsigned long lflags, enum gpiod_flags dflags)
+{
+ int status;
+
+ if (lflags & GPIO_ACTIVE_LOW)
+ set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+ if (lflags & GPIO_OPEN_DRAIN)
+ set_bit(FLAG_OPEN_DRAIN, &desc->flags);
+ if (lflags & GPIO_OPEN_SOURCE)
+ set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+
+ /* No particular flag request, return here... */
+ if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
+ pr_debug("no flags found for %s\n", con_id);
+ return 0;
+ }
+
+ /* Process flags */
+ if (dflags & GPIOD_FLAGS_BIT_DIR_OUT)
+ status = gpiod_direction_output(desc,
+ dflags & GPIOD_FLAGS_BIT_DIR_VAL);
+ else
+ status = gpiod_direction_input(desc);
+
+ return status;
+}
+
/**
* gpiod_get_index - obtain a GPIO from a multi-index GPIO function
* @dev: GPIO consumer, can be NULL for system-global GPIOs
@@ -1887,28 +1931,10 @@ struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
}
status = gpiod_request(desc, con_id);
-
if (status < 0)
return ERR_PTR(status);
- if (lookupflags & GPIO_ACTIVE_LOW)
- set_bit(FLAG_ACTIVE_LOW, &desc->flags);
- if (lookupflags & GPIO_OPEN_DRAIN)
- set_bit(FLAG_OPEN_DRAIN, &desc->flags);
- if (lookupflags & GPIO_OPEN_SOURCE)
- set_bit(FLAG_OPEN_SOURCE, &desc->flags);
-
- /* No particular flag request, return here... */
- if (!(flags & GPIOD_FLAGS_BIT_DIR_SET))
- return desc;
-
- /* Process flags */
- if (flags & GPIOD_FLAGS_BIT_DIR_OUT)
- status = gpiod_direction_output(desc,
- flags & GPIOD_FLAGS_BIT_DIR_VAL);
- else
- status = gpiod_direction_input(desc);
-
+ status = gpiod_configure_flags(desc, con_id, lookupflags, flags);
if (status < 0) {
dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
gpiod_put(desc);
@@ -2004,6 +2030,66 @@ struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
/**
+ * gpiod_hog - Hog the specified GPIO desc given the provided flags
+ * @desc: gpio whose value will be assigned
+ * @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
+ */
+int gpiod_hog(struct gpio_desc *desc, const char *name,
+ unsigned long lflags, enum gpiod_flags dflags)
+{
+ struct gpio_chip *chip;
+ struct gpio_desc *local_desc;
+ int hwnum;
+ int status;
+
+ chip = gpiod_to_chip(desc);
+ hwnum = gpio_chip_hwgpio(desc);
+
+ local_desc = gpiochip_request_own_desc(chip, hwnum, name);
+ if (IS_ERR(local_desc)) {
+ pr_debug("requesting own GPIO %s failed\n", name);
+ return PTR_ERR(local_desc);
+ }
+
+ status = gpiod_configure_flags(desc, name, lflags, dflags);
+ if (status < 0) {
+ pr_debug("setup of GPIO %s failed\n", name);
+ gpiochip_free_own_desc(desc);
+ return status;
+ }
+
+ /* Mark GPIO as hogged so it can be identified and removed later */
+ set_bit(FLAG_IS_HOGGED, &desc->flags);
+
+ pr_info("GPIO line %d (%s) hogged as %s%s\n",
+ desc_to_gpio(desc), name,
+ (dflags&GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input",
+ (dflags&GPIOD_FLAGS_BIT_DIR_OUT) ?
+ (dflags&GPIOD_FLAGS_BIT_DIR_VAL) ? "/high" : "/low":"");
+
+ return 0;
+}
+
+/**
+ * gpiochip_free_hogs - Scan gpio-controller chip and release GPIO hog
+ * @chip: gpio chip to act on
+ *
+ * This is only used by of_gpiochip_remove to free hogged gpios
+ */
+static void gpiochip_free_hogs(struct gpio_chip *chip)
+{
+ int id;
+
+ for (id = 0; id < chip->ngpio; id++) {
+ if (test_bit(FLAG_IS_HOGGED, &chip->desc[id].flags))
+ gpiochip_free_own_desc(&chip->desc[id]);
+ }
+}
+
+/**
* gpiod_put - dispose of a GPIO descriptor
* @desc: GPIO descriptor to dispose of
*
@@ -78,6 +78,7 @@ struct gpio_desc {
#define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
#define FLAG_SYSFS_DIR 10 /* show sysfs direction attribute */
+#define FLAG_IS_HOGGED 11 /* GPIO is hogged */
#define ID_SHIFT 16 /* add new flags before this one */
@@ -89,6 +90,8 @@ struct gpio_desc {
int gpiod_request(struct gpio_desc *desc, const char *label);
void gpiod_free(struct gpio_desc *desc);
+int gpiod_hog(struct gpio_desc *desc, const char *name,
+ unsigned long lflags, enum gpiod_flags dflags);
/*
* Return the GPIO number of the passed descriptor relative to its chip