/* * Generic pwmlib implementation * * Copyright (C) 2011 Sascha Hauer * 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 #include #include #include #include #include #include #include #include #include #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 */