diff options
| -rw-r--r-- | drivers/gpio/gpiolib-of.c | 111 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.c | 124 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.h | 3 |
3 files changed, 219 insertions, 19 deletions
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index 8cad8e4..468d76a 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" @@ -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 @@ -325,6 +434,8 @@ 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) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 1ca9295..1583726 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -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; } @@ -1840,6 +1843,47 @@ 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 @@ -1889,28 +1933,10 @@ 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); @@ -2006,6 +2032,66 @@ 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 * diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 550a5ea..cadba26 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -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 |
