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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * Generic pwmlib implementation
- *
- * Copyright (C) 2011 Sascha Hauer <[email protected]>
- * Copyright (C) 2011-2012 Avionic Design GmbH
- */
- #include <linux/acpi.h>
- #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 CREATE_TRACE_POINTS
- #include <trace/events/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(unsigned int count)
- {
- unsigned int start;
- start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
- count, 0);
- 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;
- }
- }
- if (pwm->chip->ops->get_state) {
- pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
- trace_pwm_get(pwm, &pwm->state);
- if (IS_ENABLED(CONFIG_PWM_DEBUG))
- pwm->last = pwm->state;
- }
- 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;
- if (pc->of_pwm_n_cells < 2)
- 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 (pc->of_pwm_n_cells >= 3) {
- 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);
- struct pwm_device *
- of_pwm_single_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
- {
- struct pwm_device *pwm;
- if (pc->of_pwm_n_cells < 1)
- return ERR_PTR(-EINVAL);
- /* validate that one cell is specified, optionally with flags */
- if (args->args_count != 1 && args->args_count != 2)
- return ERR_PTR(-EINVAL);
- pwm = pwm_request_from_chip(pc, 0, NULL);
- if (IS_ERR(pwm))
- return pwm;
- pwm->args.period = args->args[0];
- 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_single_xlate);
- static void of_pwmchip_add(struct pwm_chip *chip)
- {
- if (!chip->dev || !chip->dev->of_node)
- return;
- if (!chip->of_xlate) {
- u32 pwm_cells;
- if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
- &pwm_cells))
- pwm_cells = 2;
- chip->of_xlate = of_pwm_xlate_with_flags;
- chip->of_pwm_n_cells = pwm_cells;
- }
- 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_chip *chip)
- {
- const struct pwm_ops *ops = chip->ops;
- if (!ops->apply)
- return false;
- if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
- dev_warn(chip->dev,
- "Please implement the .get_state() callback\n");
- return true;
- }
- /**
- * pwmchip_add() - register a new PWM chip
- * @chip: the PWM chip to add
- *
- * Register a new PWM chip.
- *
- * Returns: 0 on success or a negative error code on failure.
- */
- int pwmchip_add(struct pwm_chip *chip)
- {
- struct pwm_device *pwm;
- unsigned int i;
- int ret;
- if (!chip || !chip->dev || !chip->ops || !chip->npwm)
- return -EINVAL;
- if (!pwm_ops_check(chip))
- return -EINVAL;
- mutex_lock(&pwm_lock);
- ret = alloc_pwms(chip->npwm);
- if (ret < 0)
- goto out;
- chip->base = ret;
- chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
- if (!chip->pwms) {
- ret = -ENOMEM;
- goto out;
- }
- 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;
- 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);
- /**
- * 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.
- */
- void pwmchip_remove(struct pwm_chip *chip)
- {
- pwmchip_sysfs_unexport(chip);
- mutex_lock(&pwm_lock);
- list_del_init(&chip->list);
- if (IS_ENABLED(CONFIG_OF))
- of_pwmchip_remove(chip);
- free_pwms(chip);
- mutex_unlock(&pwm_lock);
- }
- EXPORT_SYMBOL_GPL(pwmchip_remove);
- static void devm_pwmchip_remove(void *data)
- {
- struct pwm_chip *chip = data;
- pwmchip_remove(chip);
- }
- int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip)
- {
- int ret;
- ret = pwmchip_add(chip);
- if (ret)
- return ret;
- return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
- }
- EXPORT_SYMBOL_GPL(devm_pwmchip_add);
- /**
- * 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);
- static void pwm_apply_state_debug(struct pwm_device *pwm,
- const struct pwm_state *state)
- {
- struct pwm_state *last = &pwm->last;
- struct pwm_chip *chip = pwm->chip;
- struct pwm_state s1, s2;
- int err;
- if (!IS_ENABLED(CONFIG_PWM_DEBUG))
- return;
- /* No reasonable diagnosis possible without .get_state() */
- if (!chip->ops->get_state)
- return;
- /*
- * *state was just applied. Read out the hardware state and do some
- * checks.
- */
- chip->ops->get_state(chip, pwm, &s1);
- trace_pwm_get(pwm, &s1);
- /*
- * The lowlevel driver either ignored .polarity (which is a bug) or as
- * best effort inverted .polarity and fixed .duty_cycle respectively.
- * Undo this inversion and fixup for further tests.
- */
- if (s1.enabled && s1.polarity != state->polarity) {
- s2.polarity = state->polarity;
- s2.duty_cycle = s1.period - s1.duty_cycle;
- s2.period = s1.period;
- s2.enabled = s1.enabled;
- } else {
- s2 = s1;
- }
- if (s2.polarity != state->polarity &&
- state->duty_cycle < state->period)
- dev_warn(chip->dev, ".apply ignored .polarity\n");
- if (state->enabled &&
- last->polarity == state->polarity &&
- last->period > s2.period &&
- last->period <= state->period)
- dev_warn(chip->dev,
- ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
- state->period, s2.period, last->period);
- if (state->enabled && state->period < s2.period)
- dev_warn(chip->dev,
- ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
- state->period, s2.period);
- if (state->enabled &&
- last->polarity == state->polarity &&
- last->period == s2.period &&
- last->duty_cycle > s2.duty_cycle &&
- last->duty_cycle <= state->duty_cycle)
- dev_warn(chip->dev,
- ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
- state->duty_cycle, state->period,
- s2.duty_cycle, s2.period,
- last->duty_cycle, last->period);
- if (state->enabled && state->duty_cycle < s2.duty_cycle)
- dev_warn(chip->dev,
- ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
- state->duty_cycle, state->period,
- s2.duty_cycle, s2.period);
- if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
- dev_warn(chip->dev,
- "requested disabled, but yielded enabled with duty > 0\n");
- /* reapply the state that the driver reported being configured. */
- err = chip->ops->apply(chip, pwm, &s1);
- if (err) {
- *last = s1;
- dev_err(chip->dev, "failed to reapply current setting\n");
- return;
- }
- trace_pwm_apply(pwm, &s1);
- chip->ops->get_state(chip, pwm, last);
- trace_pwm_get(pwm, last);
- /* reapplication of the current state should give an exact match */
- if (s1.enabled != last->enabled ||
- s1.polarity != last->polarity ||
- (s1.enabled && s1.period != last->period) ||
- (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
- dev_err(chip->dev,
- ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
- s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
- last->enabled, last->polarity, last->duty_cycle,
- last->period);
- }
- }
- /**
- * pwm_apply_state() - atomically apply a new state to a PWM device
- * @pwm: PWM device
- * @state: new state to apply
- */
- int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
- {
- struct pwm_chip *chip;
- int err;
- /*
- * Some lowlevel driver's implementations of .apply() make use of
- * mutexes, also with some drivers only returning when the new
- * configuration is active calling pwm_apply_state() from atomic context
- * is a bad idea. So make it explicit that calling this function might
- * sleep.
- */
- might_sleep();
- if (!pwm || !state || !state->period ||
- state->duty_cycle > state->period)
- return -EINVAL;
- chip = pwm->chip;
- if (state->period == pwm->state.period &&
- state->duty_cycle == pwm->state.duty_cycle &&
- state->polarity == pwm->state.polarity &&
- state->enabled == pwm->state.enabled &&
- state->usage_power == pwm->state.usage_power)
- return 0;
- err = chip->ops->apply(chip, pwm, state);
- if (err)
- return err;
- trace_pwm_apply(pwm, state);
- pwm->state = *state;
- /*
- * only do this after pwm->state was applied as some
- * implementations of .get_state depend on this
- */
- pwm_apply_state_debug(pwm, state);
- 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 *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
- {
- struct pwm_chip *chip;
- mutex_lock(&pwm_lock);
- list_for_each_entry(chip, &pwm_chips, list)
- if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
- mutex_unlock(&pwm_lock);
- return chip;
- }
- mutex_unlock(&pwm_lock);
- return ERR_PTR(-EPROBE_DEFER);
- }
- static struct device_link *pwm_device_link_add(struct device *dev,
- struct pwm_device *pwm)
- {
- struct device_link *dl;
- if (!dev) {
- /*
- * No device for the PWM consumer has been provided. It may
- * impact the PM sequence ordering: the PWM supplier may get
- * suspended before the consumer.
- */
- dev_warn(pwm->chip->dev,
- "No consumer device specified to create a link to\n");
- return NULL;
- }
- dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
- if (!dl) {
- dev_err(dev, "failed to create device link to %s\n",
- dev_name(pwm->chip->dev));
- return ERR_PTR(-EINVAL);
- }
- return dl;
- }
- /**
- * of_pwm_get() - request a PWM via the PWM framework
- * @dev: device for PWM consumer
- * @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.
- */
- static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
- const char *con_id)
- {
- struct pwm_device *pwm = NULL;
- struct of_phandle_args args;
- struct device_link *dl;
- 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 = fwnode_to_pwmchip(of_fwnode_handle(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;
- dl = pwm_device_link_add(dev, pwm);
- if (IS_ERR(dl)) {
- /* of_xlate ended up calling pwm_request_from_chip() */
- pwm_free(pwm);
- pwm = ERR_CAST(dl);
- 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;
- }
- /**
- * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
- * @fwnode: firmware node to get the "pwms" property from
- *
- * Returns the PWM device parsed from the fwnode and index specified in the
- * "pwms" property or a negative error-code on failure.
- * Values parsed from the device tree are stored in the returned PWM device
- * object.
- *
- * This is analogous to of_pwm_get() except con_id is not yet supported.
- * ACPI entries must look like
- * Package () {"pwms", Package ()
- * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
- *
- * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
- * error code on failure.
- */
- static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
- {
- struct pwm_device *pwm;
- struct fwnode_reference_args args;
- struct pwm_chip *chip;
- int ret;
- memset(&args, 0, sizeof(args));
- ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
- if (ret < 0)
- return ERR_PTR(ret);
- if (args.nargs < 2)
- return ERR_PTR(-EPROTO);
- chip = fwnode_to_pwmchip(args.fwnode);
- if (IS_ERR(chip))
- return ERR_CAST(chip);
- pwm = pwm_request_from_chip(chip, args.args[0], NULL);
- if (IS_ERR(pwm))
- return pwm;
- pwm->args.period = args.args[1];
- pwm->args.polarity = PWM_POLARITY_NORMAL;
- if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
- pwm->args.polarity = PWM_POLARITY_INVERSED;
- return pwm;
- }
- /**
- * 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 struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
- const char *dev_id = dev ? dev_name(dev) : NULL;
- struct pwm_device *pwm;
- struct pwm_chip *chip;
- struct device_link *dl;
- unsigned int best = 0;
- struct pwm_lookup *p, *chosen = NULL;
- unsigned int match;
- int err;
- /* look up via DT first */
- if (is_of_node(fwnode))
- return of_pwm_get(dev, to_of_node(fwnode), con_id);
- /* then lookup via ACPI */
- if (is_acpi_node(fwnode)) {
- pwm = acpi_pwm_get(fwnode);
- if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
- return pwm;
- }
- /*
- * 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;
- dl = pwm_device_link_add(dev, pwm);
- if (IS_ERR(dl)) {
- pwm_free(pwm);
- return ERR_CAST(dl);
- }
- 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(void *pwm)
- {
- pwm_put(pwm);
- }
- /**
- * 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 *pwm;
- int ret;
- pwm = pwm_get(dev, con_id);
- if (IS_ERR(pwm))
- return pwm;
- ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
- if (ret)
- return ERR_PTR(ret);
- return pwm;
- }
- EXPORT_SYMBOL_GPL(devm_pwm_get);
- /**
- * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
- * @dev: device for PWM consumer
- * @fwnode: firmware node to get the PWM from
- * @con_id: consumer name
- *
- * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
- * acpi_pwm_get() for a detailed description.
- *
- * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
- * error code on failure.
- */
- struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
- struct fwnode_handle *fwnode,
- const char *con_id)
- {
- struct pwm_device *pwm = ERR_PTR(-ENODEV);
- int ret;
- if (is_of_node(fwnode))
- pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
- else if (is_acpi_node(fwnode))
- pwm = acpi_pwm_get(fwnode);
- if (IS_ERR(pwm))
- return pwm;
- ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
- if (ret)
- return ERR_PTR(ret);
- return pwm;
- }
- EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
- #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: %llu ns", state.period);
- seq_printf(s, " duty: %llu ns", state.duty_cycle);
- seq_printf(s, " polarity: %s",
- state.polarity ? "inverse" : "normal");
- if (state.usage_power)
- seq_puts(s, " usage_power");
- 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_debugfs_sops = {
- .start = pwm_seq_start,
- .next = pwm_seq_next,
- .stop = pwm_seq_stop,
- .show = pwm_seq_show,
- };
- DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
- static int __init pwm_debugfs_init(void)
- {
- debugfs_create_file("pwm", S_IFREG | 0444, NULL, NULL,
- &pwm_debugfs_fops);
- return 0;
- }
- subsys_initcall(pwm_debugfs_init);
- #endif /* CONFIG_DEBUG_FS */
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