| /* |
| * 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> |
| |
| #include <dt-bindings/pwm/pwm.h> |
| |
| #define MAX_PWMS 1024 |
| |
| static DEFINE_MUTEX(pwm_lookup_lock); |
| static LIST_HEAD(pwm_lookup_list); |
| 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 struct pwm_chip *pwmchip_find_by_name(const char *name) |
| { |
| struct pwm_chip *chip; |
| |
| if (!name) |
| return NULL; |
| |
| mutex_lock(&pwm_lock); |
| |
| list_for_each_entry(chip, &pwm_chips, list) { |
| const char *chip_name = dev_name(chip->dev); |
| |
| if (chip_name && strcmp(chip_name, name) == 0) { |
| mutex_unlock(&pwm_lock); |
| return chip; |
| } |
| } |
| |
| mutex_unlock(&pwm_lock); |
| |
| return 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; |
| } |
| |
| struct pwm_device * |
| of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) |
| { |
| struct pwm_device *pwm; |
| |
| /* check, whether the driver supports a third cell for flags */ |
| if (pc->of_pwm_n_cells < 3) |
| return ERR_PTR(-EINVAL); |
| |
| /* flags in the third cell are optional */ |
| if (args->args_count < 2) |
| return ERR_PTR(-EINVAL); |
| |
| if (args->args[0] >= pc->npwm) |
| return ERR_PTR(-EINVAL); |
| |
| pwm = pwm_request_from_chip(pc, args->args[0], NULL); |
| if (IS_ERR(pwm)) |
| return pwm; |
| |
| pwm->args.period = args->args[1]; |
| pwm->args.polarity = PWM_POLARITY_NORMAL; |
| |
| if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED) |
| pwm->args.polarity = PWM_POLARITY_INVERSED; |
| |
| return pwm; |
| } |
| EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); |
| |
| static struct pwm_device * |
| of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) |
| { |
| struct pwm_device *pwm; |
| |
| /* sanity check driver support */ |
| if (pc->of_pwm_n_cells < 2) |
| return ERR_PTR(-EINVAL); |
| |
| /* all cells are required */ |
| if (args->args_count != pc->of_pwm_n_cells) |
| return ERR_PTR(-EINVAL); |
| |
| if (args->args[0] >= pc->npwm) |
| return ERR_PTR(-EINVAL); |
| |
| pwm = pwm_request_from_chip(pc, args->args[0], NULL); |
| if (IS_ERR(pwm)) |
| return pwm; |
| |
| pwm->args.period = args->args[1]; |
| |
| return pwm; |
| } |
| |
| static void of_pwmchip_add(struct pwm_chip *chip) |
| { |
| if (!chip->dev || !chip->dev->of_node) |
| return; |
| |
| if (!chip->of_xlate) { |
| chip->of_xlate = of_pwm_simple_xlate; |
| chip->of_pwm_n_cells = 2; |
| } |
| |
| of_node_get(chip->dev->of_node); |
| } |
| |
| static void of_pwmchip_remove(struct pwm_chip *chip) |
| { |
| if (chip->dev) |
| of_node_put(chip->dev->of_node); |
| } |
| |
| /** |
| * pwm_set_chip_data() - set private chip data for a PWM |
| * @pwm: PWM device |
| * @data: pointer to chip-specific data |
| * |
| * Returns: 0 on success or a negative error code on failure. |
| */ |
| int pwm_set_chip_data(struct pwm_device *pwm, void *data) |
| { |
| if (!pwm) |
| return -EINVAL; |
| |
| pwm->chip_data = data; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(pwm_set_chip_data); |
| |
| /** |
| * pwm_get_chip_data() - get private chip data for a PWM |
| * @pwm: PWM device |
| * |
| * Returns: A pointer to the chip-private data for the PWM device. |
| */ |
| void *pwm_get_chip_data(struct pwm_device *pwm) |
| { |
| return pwm ? pwm->chip_data : NULL; |
| } |
| EXPORT_SYMBOL_GPL(pwm_get_chip_data); |
| |
| static bool pwm_ops_check(const struct pwm_ops *ops) |
| { |
| /* driver supports legacy, non-atomic operation */ |
| if (ops->config && ops->enable && ops->disable) |
| return true; |
| |
| /* driver supports atomic operation */ |
| if (ops->apply) |
| return true; |
| |
| return false; |
| } |
| |
| /** |
| * pwmchip_add_with_polarity() - register a new PWM chip |
| * @chip: the PWM chip to add |
| * @polarity: initial polarity of PWM channels |
| * |
| * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base |
| * will be used. The initial polarity for all channels is specified by the |
| * @polarity parameter. |
| * |
| * Returns: 0 on success or a negative error code on failure. |
| */ |
| int pwmchip_add_with_polarity(struct pwm_chip *chip, |
| enum pwm_polarity polarity) |
| { |
| struct pwm_device *pwm; |
| unsigned int i; |
| int ret; |
| |
| if (!chip || !chip->dev || !chip->ops || !chip->npwm) |
| return -EINVAL; |
| |
| if (!pwm_ops_check(chip->ops)) |
| return -EINVAL; |
| |
| mutex_lock(&pwm_lock); |
| |
| ret = alloc_pwms(chip->base, chip->npwm); |
| if (ret < 0) |
| goto out; |
| |
| chip->pwms = kcalloc(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; |
| pwm->state.polarity = polarity; |
| |
| if (chip->ops->get_state) |
| chip->ops->get_state(chip, pwm, &pwm->state); |
| |
| 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; |
| |
| if (IS_ENABLED(CONFIG_OF)) |
| of_pwmchip_add(chip); |
| |
| out: |
| mutex_unlock(&pwm_lock); |
| |
| if (!ret) |
| pwmchip_sysfs_export(chip); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity); |
| |
| /** |
| * 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. The initial polarity for all channels is normal. |
| * |
| * Returns: 0 on success or a negative error code on failure. |
| */ |
| int pwmchip_add(struct pwm_chip *chip) |
| { |
| return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL); |
| } |
| 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. |
| * |
| * Returns: 0 on success or a negative error code on failure. |
| */ |
| int pwmchip_remove(struct pwm_chip *chip) |
| { |
| unsigned int i; |
| int ret = 0; |
| |
| pwmchip_sysfs_unexport(chip); |
| |
| 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); |
| |
| if (IS_ENABLED(CONFIG_OF)) |
| of_pwmchip_remove(chip); |
| |
| free_pwms(chip); |
| |
| out: |
| mutex_unlock(&pwm_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(pwmchip_remove); |
| |
| /** |
| * pwm_request() - request a PWM device |
| * @pwm: global PWM device index |
| * @label: PWM device label |
| * |
| * This function is deprecated, use pwm_get() instead. |
| * |
| * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on |
| * failure. |
| */ |
| 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: A pointer to the PWM device 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 |
| * |
| * This function is deprecated, use pwm_put() instead. |
| */ |
| void pwm_free(struct pwm_device *pwm) |
| { |
| pwm_put(pwm); |
| } |
| EXPORT_SYMBOL_GPL(pwm_free); |
| |
| /** |
| * pwm_apply_state() - atomically apply a new state to a PWM device |
| * @pwm: PWM device |
| * @state: new state to apply. This can be adjusted by the PWM driver |
| * if the requested config is not achievable, for example, |
| * ->duty_cycle and ->period might be approximated. |
| */ |
| int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) |
| { |
| int err; |
| |
| if (!pwm || !state || !state->period || |
| state->duty_cycle > state->period) |
| return -EINVAL; |
| |
| if (state->period == pwm->state.period && |
| state->duty_cycle == pwm->state.duty_cycle && |
| state->polarity == pwm->state.polarity && |
| state->enabled == pwm->state.enabled) |
| return 0; |
| |
| if (pwm->chip->ops->apply) { |
| err = pwm->chip->ops->apply(pwm->chip, pwm, state); |
| if (err) |
| return err; |
| |
| pwm->state = *state; |
| } else { |
| /* |
| * FIXME: restore the initial state in case of error. |
| */ |
| if (state->polarity != pwm->state.polarity) { |
| if (!pwm->chip->ops->set_polarity) |
| return -ENOTSUPP; |
| |
| /* |
| * Changing the polarity of a running PWM is |
| * only allowed when the PWM driver implements |
| * ->apply(). |
| */ |
| if (pwm->state.enabled) { |
| pwm->chip->ops->disable(pwm->chip, pwm); |
| pwm->state.enabled = false; |
| } |
| |
| err = pwm->chip->ops->set_polarity(pwm->chip, pwm, |
| state->polarity); |
| if (err) |
| return err; |
| |
| pwm->state.polarity = state->polarity; |
| } |
| |
| if (state->period != pwm->state.period || |
| state->duty_cycle != pwm->state.duty_cycle) { |
| err = pwm->chip->ops->config(pwm->chip, pwm, |
| state->duty_cycle, |
| state->period); |
| if (err) |
| return err; |
| |
| pwm->state.duty_cycle = state->duty_cycle; |
| pwm->state.period = state->period; |
| } |
| |
| if (state->enabled != pwm->state.enabled) { |
| if (state->enabled) { |
| err = pwm->chip->ops->enable(pwm->chip, pwm); |
| if (err) |
| return err; |
| } else { |
| pwm->chip->ops->disable(pwm->chip, pwm); |
| } |
| |
| pwm->state.enabled = state->enabled; |
| } |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(pwm_apply_state); |
| |
| /** |
| * pwm_capture() - capture and report a PWM signal |
| * @pwm: PWM device |
| * @result: structure to fill with capture result |
| * @timeout: time to wait, in milliseconds, before giving up on capture |
| * |
| * Returns: 0 on success or a negative error code on failure. |
| */ |
| int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, |
| unsigned long timeout) |
| { |
| int err; |
| |
| if (!pwm || !pwm->chip->ops) |
| return -EINVAL; |
| |
| if (!pwm->chip->ops->capture) |
| return -ENOSYS; |
| |
| mutex_lock(&pwm_lock); |
| err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout); |
| mutex_unlock(&pwm_lock); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(pwm_capture); |
| |
| /** |
| * pwm_adjust_config() - adjust the current PWM config to the PWM arguments |
| * @pwm: PWM device |
| * |
| * This function will adjust the PWM config to the PWM arguments provided |
| * by the DT or PWM lookup table. This is particularly useful to adapt |
| * the bootloader config to the Linux one. |
| */ |
| int pwm_adjust_config(struct pwm_device *pwm) |
| { |
| struct pwm_state state; |
| struct pwm_args pargs; |
| |
| pwm_get_args(pwm, &pargs); |
| pwm_get_state(pwm, &state); |
| |
| /* |
| * If the current period is zero it means that either the PWM driver |
| * does not support initial state retrieval or the PWM has not yet |
| * been configured. |
| * |
| * In either case, we setup the new period and polarity, and assign a |
| * duty cycle of 0. |
| */ |
| if (!state.period) { |
| state.duty_cycle = 0; |
| state.period = pargs.period; |
| state.polarity = pargs.polarity; |
| |
| return pwm_apply_state(pwm, &state); |
| } |
| |
| /* |
| * Adjust the PWM duty cycle/period based on the period value provided |
| * in PWM args. |
| */ |
| if (pargs.period != state.period) { |
| u64 dutycycle = (u64)state.duty_cycle * pargs.period; |
| |
| do_div(dutycycle, state.period); |
| state.duty_cycle = dutycycle; |
| state.period = pargs.period; |
| } |
| |
| /* |
| * If the polarity changed, we should also change the duty cycle. |
| */ |
| if (pargs.polarity != state.polarity) { |
| state.polarity = pargs.polarity; |
| state.duty_cycle = state.period - state.duty_cycle; |
| } |
| |
| return pwm_apply_state(pwm, &state); |
| } |
| EXPORT_SYMBOL_GPL(pwm_adjust_config); |
| |
| static struct pwm_chip *of_node_to_pwmchip(struct device_node *np) |
| { |
| struct pwm_chip *chip; |
| |
| mutex_lock(&pwm_lock); |
| |
| list_for_each_entry(chip, &pwm_chips, list) |
| if (chip->dev && chip->dev->of_node == np) { |
| mutex_unlock(&pwm_lock); |
| return chip; |
| } |
| |
| mutex_unlock(&pwm_lock); |
| |
| return ERR_PTR(-EPROBE_DEFER); |
| } |
| |
| /** |
| * of_pwm_get() - request a PWM via the PWM framework |
| * @np: device node to get the PWM from |
| * @con_id: consumer name |
| * |
| * Returns the PWM device parsed from the phandle and index specified in the |
| * "pwms" property of a device tree node or a negative error-code on failure. |
| * Values parsed from the device tree are stored in the returned PWM device |
| * object. |
| * |
| * If con_id is NULL, the first PWM device listed in the "pwms" property will |
| * be requested. Otherwise the "pwm-names" property is used to do a reverse |
| * lookup of the PWM index. This also means that the "pwm-names" property |
| * becomes mandatory for devices that look up the PWM device via the con_id |
| * parameter. |
| * |
| * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
| * error code on failure. |
| */ |
| struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) |
| { |
| struct pwm_device *pwm = NULL; |
| struct of_phandle_args args; |
| struct pwm_chip *pc; |
| int index = 0; |
| int err; |
| |
| if (con_id) { |
| index = of_property_match_string(np, "pwm-names", con_id); |
| if (index < 0) |
| return ERR_PTR(index); |
| } |
| |
| err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index, |
| &args); |
| if (err) { |
| pr_err("%s(): can't parse \"pwms\" property\n", __func__); |
| return ERR_PTR(err); |
| } |
| |
| pc = of_node_to_pwmchip(args.np); |
| if (IS_ERR(pc)) { |
| if (PTR_ERR(pc) != -EPROBE_DEFER) |
| pr_err("%s(): PWM chip not found\n", __func__); |
| |
| pwm = ERR_CAST(pc); |
| goto put; |
| } |
| |
| pwm = pc->of_xlate(pc, &args); |
| if (IS_ERR(pwm)) |
| goto put; |
| |
| /* |
| * If a consumer name was not given, try to look it up from the |
| * "pwm-names" property if it exists. Otherwise use the name of |
| * the user device node. |
| */ |
| if (!con_id) { |
| err = of_property_read_string_index(np, "pwm-names", index, |
| &con_id); |
| if (err < 0) |
| con_id = np->name; |
| } |
| |
| pwm->label = con_id; |
| |
| put: |
| of_node_put(args.np); |
| |
| return pwm; |
| } |
| EXPORT_SYMBOL_GPL(of_pwm_get); |
| |
| /** |
| * pwm_add_table() - register PWM device consumers |
| * @table: array of consumers to register |
| * @num: number of consumers in table |
| */ |
| void pwm_add_table(struct pwm_lookup *table, size_t num) |
| { |
| mutex_lock(&pwm_lookup_lock); |
| |
| while (num--) { |
| list_add_tail(&table->list, &pwm_lookup_list); |
| table++; |
| } |
| |
| mutex_unlock(&pwm_lookup_lock); |
| } |
| |
| /** |
| * pwm_remove_table() - unregister PWM device consumers |
| * @table: array of consumers to unregister |
| * @num: number of consumers in table |
| */ |
| void pwm_remove_table(struct pwm_lookup *table, size_t num) |
| { |
| mutex_lock(&pwm_lookup_lock); |
| |
| while (num--) { |
| list_del(&table->list); |
| table++; |
| } |
| |
| mutex_unlock(&pwm_lookup_lock); |
| } |
| |
| /** |
| * pwm_get() - look up and request a PWM device |
| * @dev: device for PWM consumer |
| * @con_id: consumer name |
| * |
| * Lookup is first attempted using DT. If the device was not instantiated from |
| * a device tree, a PWM chip and a relative index is looked up via a table |
| * supplied by board setup code (see pwm_add_table()). |
| * |
| * Once a PWM chip has been found the specified PWM device will be requested |
| * and is ready to be used. |
| * |
| * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
| * error code on failure. |
| */ |
| struct pwm_device *pwm_get(struct device *dev, const char *con_id) |
| { |
| const char *dev_id = dev ? dev_name(dev) : NULL; |
| struct pwm_device *pwm; |
| struct pwm_chip *chip; |
| unsigned int best = 0; |
| struct pwm_lookup *p, *chosen = NULL; |
| unsigned int match; |
| int err; |
| |
| /* look up via DT first */ |
| if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) |
| return of_pwm_get(dev->of_node, con_id); |
| |
| /* |
| * We look up the provider in the static table typically provided by |
| * board setup code. We first try to lookup the consumer device by |
| * name. If the consumer device was passed in as NULL or if no match |
| * was found, we try to find the consumer by directly looking it up |
| * by name. |
| * |
| * If a match is found, the provider PWM chip is looked up by name |
| * and a PWM device is requested using the PWM device per-chip index. |
| * |
| * The lookup algorithm was shamelessly taken from the clock |
| * framework: |
| * |
| * We do slightly fuzzy matching here: |
| * An entry with a NULL ID is assumed to be a wildcard. |
| * If an entry has a device ID, it must match |
| * If an entry has a connection ID, it must match |
| * Then we take the most specific entry - with the following order |
| * of precedence: dev+con > dev only > con only. |
| */ |
| mutex_lock(&pwm_lookup_lock); |
| |
| list_for_each_entry(p, &pwm_lookup_list, list) { |
| match = 0; |
| |
| if (p->dev_id) { |
| if (!dev_id || strcmp(p->dev_id, dev_id)) |
| continue; |
| |
| match += 2; |
| } |
| |
| if (p->con_id) { |
| if (!con_id || strcmp(p->con_id, con_id)) |
| continue; |
| |
| match += 1; |
| } |
| |
| if (match > best) { |
| chosen = p; |
| |
| if (match != 3) |
| best = match; |
| else |
| break; |
| } |
| } |
| |
| mutex_unlock(&pwm_lookup_lock); |
| |
| if (!chosen) |
| return ERR_PTR(-ENODEV); |
| |
| chip = pwmchip_find_by_name(chosen->provider); |
| |
| /* |
| * If the lookup entry specifies a module, load the module and retry |
| * the PWM chip lookup. This can be used to work around driver load |
| * ordering issues if driver's can't be made to properly support the |
| * deferred probe mechanism. |
| */ |
| if (!chip && chosen->module) { |
| err = request_module(chosen->module); |
| if (err == 0) |
| chip = pwmchip_find_by_name(chosen->provider); |
| } |
| |
| if (!chip) |
| return ERR_PTR(-EPROBE_DEFER); |
| |
| pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id); |
| if (IS_ERR(pwm)) |
| return pwm; |
| |
| pwm->args.period = chosen->period; |
| pwm->args.polarity = chosen->polarity; |
| |
| return pwm; |
| } |
| EXPORT_SYMBOL_GPL(pwm_get); |
| |
| /** |
| * pwm_put() - release a PWM device |
| * @pwm: PWM device |
| */ |
| void pwm_put(struct pwm_device *pwm) |
| { |
| if (!pwm) |
| return; |
| |
| mutex_lock(&pwm_lock); |
| |
| if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { |
| pr_warn("PWM device already freed\n"); |
| goto out; |
| } |
| |
| if (pwm->chip->ops->free) |
| pwm->chip->ops->free(pwm->chip, pwm); |
| |
| pwm_set_chip_data(pwm, NULL); |
| pwm->label = NULL; |
| |
| module_put(pwm->chip->ops->owner); |
| out: |
| mutex_unlock(&pwm_lock); |
| } |
| EXPORT_SYMBOL_GPL(pwm_put); |
| |
| static void devm_pwm_release(struct device *dev, void *res) |
| { |
| pwm_put(*(struct pwm_device **)res); |
| } |
| |
| /** |
| * devm_pwm_get() - resource managed pwm_get() |
| * @dev: device for PWM consumer |
| * @con_id: consumer name |
| * |
| * This function performs like pwm_get() but the acquired PWM device will |
| * automatically be released on driver detach. |
| * |
| * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
| * error code on failure. |
| */ |
| struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id) |
| { |
| struct pwm_device **ptr, *pwm; |
| |
| ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL); |
| if (!ptr) |
| return ERR_PTR(-ENOMEM); |
| |
| pwm = pwm_get(dev, con_id); |
| if (!IS_ERR(pwm)) { |
| *ptr = pwm; |
| devres_add(dev, ptr); |
| } else { |
| devres_free(ptr); |
| } |
| |
| return pwm; |
| } |
| EXPORT_SYMBOL_GPL(devm_pwm_get); |
| |
| /** |
| * devm_of_pwm_get() - resource managed of_pwm_get() |
| * @dev: device for PWM consumer |
| * @np: device node to get the PWM from |
| * @con_id: consumer name |
| * |
| * This function performs like of_pwm_get() but the acquired PWM device will |
| * automatically be released on driver detach. |
| * |
| * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
| * error code on failure. |
| */ |
| struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, |
| const char *con_id) |
| { |
| struct pwm_device **ptr, *pwm; |
| |
| ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL); |
| if (!ptr) |
| return ERR_PTR(-ENOMEM); |
| |
| pwm = of_pwm_get(np, con_id); |
| if (!IS_ERR(pwm)) { |
| *ptr = pwm; |
| devres_add(dev, ptr); |
| } else { |
| devres_free(ptr); |
| } |
| |
| return pwm; |
| } |
| EXPORT_SYMBOL_GPL(devm_of_pwm_get); |
| |
| static int devm_pwm_match(struct device *dev, void *res, void *data) |
| { |
| struct pwm_device **p = res; |
| |
| if (WARN_ON(!p || !*p)) |
| return 0; |
| |
| return *p == data; |
| } |
| |
| /** |
| * devm_pwm_put() - resource managed pwm_put() |
| * @dev: device for PWM consumer |
| * @pwm: PWM device |
| * |
| * Release a PWM previously allocated using devm_pwm_get(). Calling this |
| * function is usually not needed because devm-allocated resources are |
| * automatically released on driver detach. |
| */ |
| void devm_pwm_put(struct device *dev, struct pwm_device *pwm) |
| { |
| WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm)); |
| } |
| EXPORT_SYMBOL_GPL(devm_pwm_put); |
| |
| #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]; |
| struct pwm_state state; |
| |
| pwm_get_state(pwm, &state); |
| |
| seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label); |
| |
| if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
| seq_puts(s, " requested"); |
| |
| if (state.enabled) |
| seq_puts(s, " enabled"); |
| |
| seq_printf(s, " period: %u ns", state.period); |
| seq_printf(s, " duty: %u ns", state.duty_cycle); |
| seq_printf(s, " polarity: %s", |
| state.polarity ? "inverse" : "normal"); |
| |
| seq_puts(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" : ""); |
| |
| 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 */ |