diff options
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 1347 |
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 */ |