| /* |
| * Generic pwmlib implementation |
| * |
| * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de> |
| * Copyright (C) 2011-2012 Avionic Design GmbH |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2, or (at your option) |
| * any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; see the file COPYING. If not, write to |
| * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/pwm.h> |
| #include <linux/radix-tree.h> |
| #include <linux/list.h> |
| #include <linux/mutex.h> |
| #include <linux/err.h> |
| #include <linux/slab.h> |
| #include <linux/device.h> |
| #include <linux/debugfs.h> |
| #include <linux/seq_file.h> |
| |
| #define MAX_PWMS 1024 |
| |
| static DEFINE_MUTEX(pwm_lock); |
| static LIST_HEAD(pwm_chips); |
| static DECLARE_BITMAP(allocated_pwms, MAX_PWMS); |
| static RADIX_TREE(pwm_tree, GFP_KERNEL); |
| |
| static struct pwm_device *pwm_to_device(unsigned int pwm) |
| { |
| return radix_tree_lookup(&pwm_tree, pwm); |
| } |
| |
| static int alloc_pwms(int pwm, unsigned int count) |
| { |
| unsigned int from = 0; |
| unsigned int start; |
| |
| if (pwm >= MAX_PWMS) |
| return -EINVAL; |
| |
| if (pwm >= 0) |
| from = pwm; |
| |
| start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from, |
| count, 0); |
| |
| if (pwm >= 0 && start != pwm) |
| return -EEXIST; |
| |
| if (start + count > MAX_PWMS) |
| return -ENOSPC; |
| |
| return start; |
| } |
| |
| static void free_pwms(struct pwm_chip *chip) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < chip->npwm; i++) { |
| struct pwm_device *pwm = &chip->pwms[i]; |
| radix_tree_delete(&pwm_tree, pwm->pwm); |
| } |
| |
| bitmap_clear(allocated_pwms, chip->base, chip->npwm); |
| |
| kfree(chip->pwms); |
| chip->pwms = NULL; |
| } |
| |
| static int pwm_device_request(struct pwm_device *pwm, const char *label) |
| { |
| int err; |
| |
| if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
| return -EBUSY; |
| |
| if (!try_module_get(pwm->chip->ops->owner)) |
| return -ENODEV; |
| |
| if (pwm->chip->ops->request) { |
| err = pwm->chip->ops->request(pwm->chip, pwm); |
| if (err) { |
| module_put(pwm->chip->ops->owner); |
| return err; |
| } |
| } |
| |
| set_bit(PWMF_REQUESTED, &pwm->flags); |
| pwm->label = label; |
| |
| return 0; |
| } |
| |
| /** |
| * pwm_set_chip_data() - set private chip data for a PWM |
| * @pwm: PWM device |
| * @data: pointer to chip-specific data |
| */ |
| int pwm_set_chip_data(struct pwm_device *pwm, void *data) |
| { |
| if (!pwm) |
| return -EINVAL; |
| |
| pwm->chip_data = data; |
| |
| return 0; |
| } |
| |
| /** |
| * pwm_get_chip_data() - get private chip data for a PWM |
| * @pwm: PWM device |
| */ |
| void *pwm_get_chip_data(struct pwm_device *pwm) |
| { |
| return pwm ? pwm->chip_data : NULL; |
| } |
| |
| /** |
| * pwmchip_add() - register a new PWM chip |
| * @chip: the PWM chip to add |
| * |
| * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base |
| * will be used. |
| */ |
| int pwmchip_add(struct pwm_chip *chip) |
| { |
| struct pwm_device *pwm; |
| unsigned int i; |
| int ret; |
| |
| if (!chip || !chip->dev || !chip->ops || !chip->ops->config || |
| !chip->ops->enable || !chip->ops->disable) |
| return -EINVAL; |
| |
| mutex_lock(&pwm_lock); |
| |
| ret = alloc_pwms(chip->base, chip->npwm); |
| if (ret < 0) |
| goto out; |
| |
| chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL); |
| if (!chip->pwms) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| chip->base = ret; |
| |
| for (i = 0; i < chip->npwm; i++) { |
| pwm = &chip->pwms[i]; |
| |
| pwm->chip = chip; |
| pwm->pwm = chip->base + i; |
| pwm->hwpwm = i; |
| |
| radix_tree_insert(&pwm_tree, pwm->pwm, pwm); |
| } |
| |
| bitmap_set(allocated_pwms, chip->base, chip->npwm); |
| |
| INIT_LIST_HEAD(&chip->list); |
| list_add(&chip->list, &pwm_chips); |
| |
| ret = 0; |
| |
| out: |
| mutex_unlock(&pwm_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(pwmchip_add); |
| |
| /** |
| * pwmchip_remove() - remove a PWM chip |
| * @chip: the PWM chip to remove |
| * |
| * Removes a PWM chip. This function may return busy if the PWM chip provides |
| * a PWM device that is still requested. |
| */ |
| int pwmchip_remove(struct pwm_chip *chip) |
| { |
| unsigned int i; |
| int ret = 0; |
| |
| mutex_lock(&pwm_lock); |
| |
| for (i = 0; i < chip->npwm; i++) { |
| struct pwm_device *pwm = &chip->pwms[i]; |
| |
| if (test_bit(PWMF_REQUESTED, &pwm->flags)) { |
| ret = -EBUSY; |
| goto out; |
| } |
| } |
| |
| list_del_init(&chip->list); |
| free_pwms(chip); |
| |
| out: |
| mutex_unlock(&pwm_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(pwmchip_remove); |
| |
| /** |
| * pwm_request() - request a PWM device |
| * @pwm_id: global PWM device index |
| * @label: PWM device label |
| */ |
| struct pwm_device *pwm_request(int pwm, const char *label) |
| { |
| struct pwm_device *dev; |
| int err; |
| |
| if (pwm < 0 || pwm >= MAX_PWMS) |
| return ERR_PTR(-EINVAL); |
| |
| mutex_lock(&pwm_lock); |
| |
| dev = pwm_to_device(pwm); |
| if (!dev) { |
| dev = ERR_PTR(-EPROBE_DEFER); |
| goto out; |
| } |
| |
| err = pwm_device_request(dev, label); |
| if (err < 0) |
| dev = ERR_PTR(err); |
| |
| out: |
| mutex_unlock(&pwm_lock); |
| |
| return dev; |
| } |
| EXPORT_SYMBOL_GPL(pwm_request); |
| |
| /** |
| * pwm_request_from_chip() - request a PWM device relative to a PWM chip |
| * @chip: PWM chip |
| * @index: per-chip index of the PWM to request |
| * @label: a literal description string of this PWM |
| * |
| * Returns the PWM at the given index of the given PWM chip. A negative error |
| * code is returned if the index is not valid for the specified PWM chip or |
| * if the PWM device cannot be requested. |
| */ |
| struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
| unsigned int index, |
| const char *label) |
| { |
| struct pwm_device *pwm; |
| int err; |
| |
| if (!chip || index >= chip->npwm) |
| return ERR_PTR(-EINVAL); |
| |
| mutex_lock(&pwm_lock); |
| pwm = &chip->pwms[index]; |
| |
| err = pwm_device_request(pwm, label); |
| if (err < 0) |
| pwm = ERR_PTR(err); |
| |
| mutex_unlock(&pwm_lock); |
| return pwm; |
| } |
| EXPORT_SYMBOL_GPL(pwm_request_from_chip); |
| |
| /** |
| * pwm_free() - free a PWM device |
| * @pwm: PWM device |
| */ |
| void pwm_free(struct pwm_device *pwm) |
| { |
| mutex_lock(&pwm_lock); |
| |
| if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { |
| pr_warning("PWM device already freed\n"); |
| goto out; |
| } |
| |
| if (pwm->chip->ops->free) |
| pwm->chip->ops->free(pwm->chip, pwm); |
| |
| pwm->label = NULL; |
| |
| module_put(pwm->chip->ops->owner); |
| out: |
| mutex_unlock(&pwm_lock); |
| } |
| EXPORT_SYMBOL_GPL(pwm_free); |
| |
| /** |
| * pwm_config() - change a PWM device configuration |
| * @pwm: PWM device |
| * @duty_ns: "on" time (in nanoseconds) |
| * @period_ns: duration (in nanoseconds) of one cycle |
| */ |
| int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| { |
| if (!pwm || period_ns == 0 || duty_ns > period_ns) |
| return -EINVAL; |
| |
| return pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns); |
| } |
| EXPORT_SYMBOL_GPL(pwm_config); |
| |
| /** |
| * pwm_enable() - start a PWM output toggling |
| * @pwm: PWM device |
| */ |
| int pwm_enable(struct pwm_device *pwm) |
| { |
| if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags)) |
| return pwm->chip->ops->enable(pwm->chip, pwm); |
| |
| return pwm ? 0 : -EINVAL; |
| } |
| EXPORT_SYMBOL_GPL(pwm_enable); |
| |
| /** |
| * pwm_disable() - stop a PWM output toggling |
| * @pwm: PWM device |
| */ |
| void pwm_disable(struct pwm_device *pwm) |
| { |
| if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags)) |
| pwm->chip->ops->disable(pwm->chip, pwm); |
| } |
| EXPORT_SYMBOL_GPL(pwm_disable); |
| |
| #ifdef CONFIG_DEBUG_FS |
| static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < chip->npwm; i++) { |
| struct pwm_device *pwm = &chip->pwms[i]; |
| |
| seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label); |
| |
| if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
| seq_printf(s, " requested"); |
| |
| if (test_bit(PWMF_ENABLED, &pwm->flags)) |
| seq_printf(s, " enabled"); |
| |
| seq_printf(s, "\n"); |
| } |
| } |
| |
| static void *pwm_seq_start(struct seq_file *s, loff_t *pos) |
| { |
| mutex_lock(&pwm_lock); |
| s->private = ""; |
| |
| return seq_list_start(&pwm_chips, *pos); |
| } |
| |
| static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos) |
| { |
| s->private = "\n"; |
| |
| return seq_list_next(v, &pwm_chips, pos); |
| } |
| |
| static void pwm_seq_stop(struct seq_file *s, void *v) |
| { |
| mutex_unlock(&pwm_lock); |
| } |
| |
| static int pwm_seq_show(struct seq_file *s, void *v) |
| { |
| struct pwm_chip *chip = list_entry(v, struct pwm_chip, list); |
| |
| seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private, |
| chip->dev->bus ? chip->dev->bus->name : "no-bus", |
| dev_name(chip->dev), chip->npwm, |
| (chip->npwm != 1) ? "s" : ""); |
| |
| if (chip->ops->dbg_show) |
| chip->ops->dbg_show(chip, s); |
| else |
| pwm_dbg_show(chip, s); |
| |
| return 0; |
| } |
| |
| static const struct seq_operations pwm_seq_ops = { |
| .start = pwm_seq_start, |
| .next = pwm_seq_next, |
| .stop = pwm_seq_stop, |
| .show = pwm_seq_show, |
| }; |
| |
| static int pwm_seq_open(struct inode *inode, struct file *file) |
| { |
| return seq_open(file, &pwm_seq_ops); |
| } |
| |
| static const struct file_operations pwm_debugfs_ops = { |
| .owner = THIS_MODULE, |
| .open = pwm_seq_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| }; |
| |
| static int __init pwm_debugfs_init(void) |
| { |
| debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL, |
| &pwm_debugfs_ops); |
| |
| return 0; |
| } |
| |
| subsys_initcall(pwm_debugfs_init); |
| #endif /* CONFIG_DEBUG_FS */ |