2 * OF helpers for the GPIO API
4 * Copyright (c) 2007-2008 MontaVista Software, Inc.
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/errno.h>
17 #include <linux/module.h>
19 #include <linux/gpio/consumer.h>
21 #include <linux/of_address.h>
22 #include <linux/of_gpio.h>
23 #include <linux/pinctrl/pinctrl.h>
24 #include <linux/slab.h>
25 #include <linux/gpio/machine.h>
29 /* Private data structure for of_gpiochip_find_and_xlate */
31 enum of_gpio_flags *flags;
32 struct of_phandle_args gpiospec;
34 struct gpio_desc *out_gpio;
37 /* Private function for resolving node pointer to gpio_chip */
38 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
40 struct gg_data *gg_data = data;
43 if ((gc->of_node != gg_data->gpiospec.np) ||
44 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
48 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
50 /* We've found a gpio chip, but the translation failed.
51 * Store translation error in out_gpio.
52 * Return false to keep looking, as more than one gpio chip
53 * could be registered per of-node.
55 gg_data->out_gpio = ERR_PTR(ret);
59 gg_data->out_gpio = gpiochip_get_desc(gc, ret);
64 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
65 * @np: device node to get GPIO from
66 * @propname: property name containing gpio specifier(s)
67 * @index: index of the GPIO
68 * @flags: a flags pointer to fill in
70 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
71 * value on the error condition. If @flags is not NULL the function also fills
72 * in flags for the GPIO.
74 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
75 const char *propname, int index, enum of_gpio_flags *flags)
77 /* Return -EPROBE_DEFER to support probe() functions to be called
78 * later when the GPIO actually becomes available
80 struct gg_data gg_data = {
82 .out_gpio = ERR_PTR(-EPROBE_DEFER)
86 /* .of_xlate might decide to not fill in the flags, so clear it. */
90 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
93 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
94 __func__, propname, np->full_name, index);
98 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
100 of_node_put(gg_data.gpiospec.np);
101 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
102 __func__, propname, np->full_name, index,
103 PTR_ERR_OR_ZERO(gg_data.out_gpio));
104 return gg_data.out_gpio;
107 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
108 int index, enum of_gpio_flags *flags)
110 struct gpio_desc *desc;
112 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
115 return PTR_ERR(desc);
117 return desc_to_gpio(desc);
119 EXPORT_SYMBOL(of_get_named_gpio_flags);
122 * of_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API
123 * @np: device node to get GPIO from
124 * @name: GPIO line name
125 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
127 * @dflags: gpiod_flags - optional GPIO initialization flags
129 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
130 * value on the error condition.
132 static struct gpio_desc *of_get_gpio_hog(struct device_node *np,
134 enum gpio_lookup_flags *lflags,
135 enum gpiod_flags *dflags)
137 struct device_node *chip_np;
138 enum of_gpio_flags xlate_flags;
139 struct gg_data gg_data = {
140 .flags = &xlate_flags,
145 chip_np = np->parent;
147 return ERR_PTR(-EINVAL);
153 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
157 if (tmp > MAX_PHANDLE_ARGS)
158 return ERR_PTR(-EINVAL);
160 gg_data.gpiospec.args_count = tmp;
161 gg_data.gpiospec.np = chip_np;
162 for (i = 0; i < tmp; i++) {
163 ret = of_property_read_u32_index(np, "gpios", i,
164 &gg_data.gpiospec.args[i]);
169 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
170 if (!gg_data.out_gpio) {
171 if (np->parent == np)
172 return ERR_PTR(-ENXIO);
174 return ERR_PTR(-EINVAL);
177 if (xlate_flags & OF_GPIO_ACTIVE_LOW)
178 *lflags |= GPIO_ACTIVE_LOW;
180 if (of_property_read_bool(np, "input"))
182 else if (of_property_read_bool(np, "output-low"))
183 *dflags |= GPIOD_OUT_LOW;
184 else if (of_property_read_bool(np, "output-high"))
185 *dflags |= GPIOD_OUT_HIGH;
187 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
188 desc_to_gpio(gg_data.out_gpio), np->name);
189 return ERR_PTR(-EINVAL);
192 if (name && of_property_read_string(np, "line-name", name))
195 return gg_data.out_gpio;
199 * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested
200 * @chip: gpio chip to act on
202 * This is only used by of_gpiochip_add to request/set GPIO initial
205 static void of_gpiochip_scan_hogs(struct gpio_chip *chip)
207 struct gpio_desc *desc = NULL;
208 struct device_node *np;
210 enum gpio_lookup_flags lflags;
211 enum gpiod_flags dflags;
213 for_each_child_of_node(chip->of_node, np) {
214 if (!of_property_read_bool(np, "gpio-hog"))
217 desc = of_get_gpio_hog(np, &name, &lflags, &dflags);
221 if (gpiod_hog(desc, name, lflags, dflags))
227 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
228 * @gc: pointer to the gpio_chip structure
229 * @np: device node of the GPIO chip
230 * @gpio_spec: gpio specifier as found in the device tree
231 * @flags: a flags pointer to fill in
233 * This is simple translation function, suitable for the most 1:1 mapped
234 * gpio chips. This function performs only one sanity check: whether gpio
235 * is less than ngpios (that is specified in the gpio_chip).
237 int of_gpio_simple_xlate(struct gpio_chip *gc,
238 const struct of_phandle_args *gpiospec, u32 *flags)
241 * We're discouraging gpio_cells < 2, since that way you'll have to
242 * write your own xlate function (that will have to retrieve the GPIO
243 * number and the flags from a single gpio cell -- this is possible,
244 * but not recommended).
246 if (gc->of_gpio_n_cells < 2) {
251 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
254 if (gpiospec->args[0] >= gc->ngpio)
258 *flags = gpiospec->args[1];
260 return gpiospec->args[0];
262 EXPORT_SYMBOL(of_gpio_simple_xlate);
265 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
266 * @np: device node of the GPIO chip
267 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
269 * To use this function you should allocate and fill mm_gc with:
271 * 1) In the gpio_chip structure:
272 * - all the callbacks
274 * - of_xlate callback (optional)
276 * 3) In the of_mm_gpio_chip structure:
277 * - save_regs callback (optional)
279 * If succeeded, this function will map bank's memory and will
280 * do all necessary work for you. Then you'll able to use .regs
281 * to manage GPIOs from the callbacks.
283 int of_mm_gpiochip_add(struct device_node *np,
284 struct of_mm_gpio_chip *mm_gc)
287 struct gpio_chip *gc = &mm_gc->gc;
289 gc->label = kstrdup(np->full_name, GFP_KERNEL);
293 mm_gc->regs = of_iomap(np, 0);
299 if (mm_gc->save_regs)
300 mm_gc->save_regs(mm_gc);
302 mm_gc->gc.of_node = np;
304 ret = gpiochip_add(gc);
310 iounmap(mm_gc->regs);
314 pr_err("%s: GPIO chip registration failed with status %d\n",
318 EXPORT_SYMBOL(of_mm_gpiochip_add);
321 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
322 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
324 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
326 struct gpio_chip *gc = &mm_gc->gc;
332 iounmap(mm_gc->regs);
335 EXPORT_SYMBOL(of_mm_gpiochip_remove);
337 #ifdef CONFIG_PINCTRL
338 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
340 struct device_node *np = chip->of_node;
341 struct of_phandle_args pinspec;
342 struct pinctrl_dev *pctldev;
345 static const char group_names_propname[] = "gpio-ranges-group-names";
346 struct property *group_names;
351 group_names = of_find_property(np, group_names_propname, NULL);
354 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
359 pctldev = of_pinctrl_get(pinspec.np);
361 return -EPROBE_DEFER;
363 if (pinspec.args[2]) {
365 of_property_read_string_index(np,
366 group_names_propname,
369 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
374 /* npins != 0: linear range */
375 ret = gpiochip_add_pin_range(chip,
376 pinctrl_dev_get_devname(pctldev),
383 /* npins == 0: special range */
384 if (pinspec.args[1]) {
385 pr_err("%s: Illegal gpio-range format.\n",
391 pr_err("%s: GPIO group range requested but no %s property.\n",
392 np->full_name, group_names_propname);
396 ret = of_property_read_string_index(np,
397 group_names_propname,
403 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
408 ret = gpiochip_add_pingroup_range(chip, pctldev,
409 pinspec.args[0], name);
419 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
422 int of_gpiochip_add(struct gpio_chip *chip)
426 if ((!chip->of_node) && (chip->dev))
427 chip->of_node = chip->dev->of_node;
432 if (!chip->of_xlate) {
433 chip->of_gpio_n_cells = 2;
434 chip->of_xlate = of_gpio_simple_xlate;
437 status = of_gpiochip_add_pin_range(chip);
441 of_node_get(chip->of_node);
443 of_gpiochip_scan_hogs(chip);
448 void of_gpiochip_remove(struct gpio_chip *chip)
450 gpiochip_remove_pin_ranges(chip);
451 of_node_put(chip->of_node);