summaryrefslogtreecommitdiffstats
path: root/drivers/pwm/core.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--drivers/pwm/core.c1347
1 files changed, 1347 insertions, 0 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
new file mode 100644
index 000000000..1f16f5365
--- /dev/null
+++ b/drivers/pwm/core.c
@@ -0,0 +1,1347 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic pwmlib implementation
+ *
+ * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
+ * 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(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;
+ }
+ }
+
+ 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;
+
+ /* 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_chip *chip)
+{
+
+ const struct pwm_ops *ops = chip->ops;
+
+ /* driver supports legacy, non-atomic operation */
+ if (ops->config && ops->enable && ops->disable) {
+ if (IS_ENABLED(CONFIG_PWM_DEBUG))
+ dev_warn(chip->dev,
+ "Driver needs updating to atomic API\n");
+
+ return true;
+ }
+
+ 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_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))
+ 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;
+
+ 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);
+
+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;
+
+ 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)
+ return 0;
+
+ if (chip->ops->apply) {
+ 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);
+ } else {
+ /*
+ * FIXME: restore the initial state in case of error.
+ */
+ if (state->polarity != pwm->state.polarity) {
+ if (!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) {
+ chip->ops->disable(chip, pwm);
+ pwm->state.enabled = false;
+ }
+
+ err = chip->ops->set_polarity(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 = 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 = chip->ops->enable(chip, pwm);
+ if (err)
+ return err;
+ } else {
+ chip->ops->disable(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);
+}
+
+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.
+ */
+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 = 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;
+
+ 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;
+}
+EXPORT_SYMBOL_GPL(of_pwm_get);
+
+#if IS_ENABLED(CONFIG_ACPI)
+static struct pwm_chip *device_to_pwmchip(struct device *dev)
+{
+ struct pwm_chip *chip;
+
+ mutex_lock(&pwm_lock);
+
+ list_for_each_entry(chip, &pwm_chips, list) {
+ struct acpi_device *adev = ACPI_COMPANION(chip->dev);
+
+ if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
+ mutex_unlock(&pwm_lock);
+ return chip;
+ }
+ }
+
+ mutex_unlock(&pwm_lock);
+
+ return ERR_PTR(-EPROBE_DEFER);
+}
+#endif
+
+/**
+ * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
+ * @fwnode: firmware node to get the "pwm" 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(struct fwnode_handle *fwnode)
+{
+ struct pwm_device *pwm = ERR_PTR(-ENODEV);
+#if IS_ENABLED(CONFIG_ACPI)
+ struct fwnode_reference_args args;
+ struct acpi_device *acpi;
+ 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);
+
+ acpi = to_acpi_device_node(args.fwnode);
+ if (!acpi)
+ return ERR_PTR(-EINVAL);
+
+ if (args.nargs < 2)
+ return ERR_PTR(-EPROTO);
+
+ chip = device_to_pwmchip(&acpi->dev);
+ 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;
+#endif
+
+ 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 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_ENABLED(CONFIG_OF) && dev && dev->of_node)
+ return of_pwm_get(dev, dev->of_node, con_id);
+
+ /* then lookup via ACPI */
+ if (dev && is_acpi_node(dev->fwnode)) {
+ pwm = acpi_pwm_get(dev->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(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(dev, 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);
+
+/**
+ * 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 **ptr, *pwm = ERR_PTR(-ENODEV);
+
+ ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ 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)) {
+ *ptr = pwm;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return pwm;
+}
+EXPORT_SYMBOL_GPL(devm_fwnode_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: %llu ns", state.period);
+ seq_printf(s, " duty: %llu 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_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 | S_IRUGO, NULL, NULL,
+ &pwm_debugfs_fops);
+
+ return 0;
+}
+subsys_initcall(pwm_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */