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gbmc / linux / ed471e1984939a500eea179bc16e1c2aadf00db5 / . / drivers / pwm / core.c
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// 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
*/
#define DEFAULT_SYMBOL_NAMESPACE "PWM"
#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/of.h>
#include <linux/pwm.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>
/* protects access to pwm_chips */
static DEFINE_MUTEX(pwm_lock);
static DEFINE_IDR(pwm_chips);
static void pwmchip_lock(struct pwm_chip *chip)
{
if (chip->atomic)
spin_lock(&chip->atomic_lock);
else
mutex_lock(&chip->nonatomic_lock);
}
static void pwmchip_unlock(struct pwm_chip *chip)
{
if (chip->atomic)
spin_unlock(&chip->atomic_lock);
else
mutex_unlock(&chip->nonatomic_lock);
}
DEFINE_GUARD(pwmchip, struct pwm_chip *, pwmchip_lock(_T), pwmchip_unlock(_T))
static bool pwm_wf_valid(const struct pwm_waveform *wf)
{
/*
* For now restrict waveforms to period_length_ns <= S64_MAX to provide
* some space for future extensions. One possibility is to simplify
* representing waveforms with inverted polarity using negative values
* somehow.
*/
if (wf->period_length_ns > S64_MAX)
return false;
if (wf->duty_length_ns > wf->period_length_ns)
return false;
/*
* .duty_offset_ns is supposed to be smaller than .period_length_ns, apart
* from the corner case .duty_offset_ns == 0 && .period_length_ns == 0.
*/
if (wf->duty_offset_ns && wf->duty_offset_ns >= wf->period_length_ns)
return false;
return true;
}
static void pwm_wf2state(const struct pwm_waveform *wf, struct pwm_state *state)
{
if (wf->period_length_ns) {
if (wf->duty_length_ns + wf->duty_offset_ns < wf->period_length_ns)
*state = (struct pwm_state){
.enabled = true,
.polarity = PWM_POLARITY_NORMAL,
.period = wf->period_length_ns,
.duty_cycle = wf->duty_length_ns,
};
else
*state = (struct pwm_state){
.enabled = true,
.polarity = PWM_POLARITY_INVERSED,
.period = wf->period_length_ns,
.duty_cycle = wf->period_length_ns - wf->duty_length_ns,
};
} else {
*state = (struct pwm_state){
.enabled = false,
};
}
}
static void pwm_state2wf(const struct pwm_state *state, struct pwm_waveform *wf)
{
if (state->enabled) {
if (state->polarity == PWM_POLARITY_NORMAL)
*wf = (struct pwm_waveform){
.period_length_ns = state->period,
.duty_length_ns = state->duty_cycle,
.duty_offset_ns = 0,
};
else
*wf = (struct pwm_waveform){
.period_length_ns = state->period,
.duty_length_ns = state->period - state->duty_cycle,
.duty_offset_ns = state->duty_cycle,
};
} else {
*wf = (struct pwm_waveform){
.period_length_ns = 0,
};
}
}
static int pwmwfcmp(const struct pwm_waveform *a, const struct pwm_waveform *b)
{
if (a->period_length_ns > b->period_length_ns)
return 1;
if (a->period_length_ns < b->period_length_ns)
return -1;
if (a->duty_length_ns > b->duty_length_ns)
return 1;
if (a->duty_length_ns < b->duty_length_ns)
return -1;
if (a->duty_offset_ns > b->duty_offset_ns)
return 1;
if (a->duty_offset_ns < b->duty_offset_ns)
return -1;
return 0;
}
static bool pwm_check_rounding(const struct pwm_waveform *wf,
const struct pwm_waveform *wf_rounded)
{
if (!wf->period_length_ns)
return true;
if (wf->period_length_ns < wf_rounded->period_length_ns)
return false;
if (wf->duty_length_ns < wf_rounded->duty_length_ns)
return false;
if (wf->duty_offset_ns < wf_rounded->duty_offset_ns)
return false;
return true;
}
static int __pwm_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_waveform *wf, void *wfhw)
{
const struct pwm_ops *ops = chip->ops;
int ret;
ret = ops->round_waveform_tohw(chip, pwm, wf, wfhw);
trace_pwm_round_waveform_tohw(pwm, wf, wfhw, ret);
return ret;
}
static int __pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
const void *wfhw, struct pwm_waveform *wf)
{
const struct pwm_ops *ops = chip->ops;
int ret;
ret = ops->round_waveform_fromhw(chip, pwm, wfhw, wf);
trace_pwm_round_waveform_fromhw(pwm, wfhw, wf, ret);
return ret;
}
static int __pwm_read_waveform(struct pwm_chip *chip, struct pwm_device *pwm, void *wfhw)
{
const struct pwm_ops *ops = chip->ops;
int ret;
ret = ops->read_waveform(chip, pwm, wfhw);
trace_pwm_read_waveform(pwm, wfhw, ret);
return ret;
}
static int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, const void *wfhw)
{
const struct pwm_ops *ops = chip->ops;
int ret;
ret = ops->write_waveform(chip, pwm, wfhw);
trace_pwm_write_waveform(pwm, wfhw, ret);
return ret;
}
#define WFHWSIZE 20
/**
* pwm_round_waveform_might_sleep - Query hardware capabilities
* Cannot be used in atomic context.
* @pwm: PWM device
* @wf: waveform to round and output parameter
*
* Typically a given waveform cannot be implemented exactly by hardware, e.g.
* because hardware only supports coarse period resolution or no duty_offset.
* This function returns the actually implemented waveform if you pass wf to
* pwm_set_waveform_might_sleep now.
*
* Note however that the world doesn't stop turning when you call it, so when
* doing
*
* pwm_round_waveform_might_sleep(mypwm, &wf);
* pwm_set_waveform_might_sleep(mypwm, &wf, true);
*
* the latter might fail, e.g. because an input clock changed its rate between
* these two calls and the waveform determined by
* pwm_round_waveform_might_sleep() cannot be implemented any more.
*
* Returns 0 on success, 1 if there is no valid hardware configuration matching
* the input waveform under the PWM rounding rules or a negative errno.
*/
int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf)
{
struct pwm_chip *chip = pwm->chip;
const struct pwm_ops *ops = chip->ops;
struct pwm_waveform wf_req = *wf;
char wfhw[WFHWSIZE];
int ret_tohw, ret_fromhw;
BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
if (!pwmchip_supports_waveform(chip))
return -EOPNOTSUPP;
if (!pwm_wf_valid(wf))
return -EINVAL;
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, wfhw);
if (ret_tohw < 0)
return ret_tohw;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_tohw > 1)
dev_err(&chip->dev, "Unexpected return value from __pwm_round_waveform_tohw: requested %llu/%llu [+%llu], return value %d\n",
wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw);
ret_fromhw = __pwm_round_waveform_fromhw(chip, pwm, wfhw, wf);
if (ret_fromhw < 0)
return ret_fromhw;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_fromhw > 0)
dev_err(&chip->dev, "Unexpected return value from __pwm_round_waveform_fromhw: requested %llu/%llu [+%llu], return value %d\n",
wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw);
if (IS_ENABLED(CONFIG_PWM_DEBUG) &&
ret_tohw == 0 && !pwm_check_rounding(&wf_req, wf))
dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns,
wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
return ret_tohw;
}
EXPORT_SYMBOL_GPL(pwm_round_waveform_might_sleep);
/**
* pwm_get_waveform_might_sleep - Query hardware about current configuration
* Cannot be used in atomic context.
* @pwm: PWM device
* @wf: output parameter
*
* Stores the current configuration of the PWM in @wf. Note this is the
* equivalent of pwm_get_state_hw() (and not pwm_get_state()) for pwm_waveform.
*/
int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf)
{
struct pwm_chip *chip = pwm->chip;
const struct pwm_ops *ops = chip->ops;
char wfhw[WFHWSIZE];
int err;
BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
if (!pwmchip_supports_waveform(chip) || !ops->read_waveform)
return -EOPNOTSUPP;
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
err = __pwm_read_waveform(chip, pwm, &wfhw);
if (err)
return err;
return __pwm_round_waveform_fromhw(chip, pwm, &wfhw, wf);
}
EXPORT_SYMBOL_GPL(pwm_get_waveform_might_sleep);
/* Called with the pwmchip lock held */
static int __pwm_set_waveform(struct pwm_device *pwm,
const struct pwm_waveform *wf,
bool exact)
{
struct pwm_chip *chip = pwm->chip;
const struct pwm_ops *ops = chip->ops;
char wfhw[WFHWSIZE];
struct pwm_waveform wf_rounded;
int err;
BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
if (!pwmchip_supports_waveform(chip))
return -EOPNOTSUPP;
if (!pwm_wf_valid(wf))
return -EINVAL;
err = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
if (err)
return err;
if ((IS_ENABLED(CONFIG_PWM_DEBUG) || exact) && wf->period_length_ns) {
err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
if (err)
return err;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && !pwm_check_rounding(wf, &wf_rounded))
dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
if (exact && pwmwfcmp(wf, &wf_rounded)) {
dev_dbg(&chip->dev, "Requested no rounding, but %llu/%llu [+%llu] -> %llu/%llu [+%llu]\n",
wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
return 1;
}
}
err = __pwm_write_waveform(chip, pwm, &wfhw);
if (err)
return err;
/* update .state */
pwm_wf2state(wf, &pwm->state);
if (IS_ENABLED(CONFIG_PWM_DEBUG) && ops->read_waveform && wf->period_length_ns) {
struct pwm_waveform wf_set;
err = __pwm_read_waveform(chip, pwm, &wfhw);
if (err)
/* maybe ignore? */
return err;
err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_set);
if (err)
/* maybe ignore? */
return err;
if (pwmwfcmp(&wf_set, &wf_rounded) != 0)
dev_err(&chip->dev,
"Unexpected setting: requested %llu/%llu [+%llu], expected %llu/%llu [+%llu], set %llu/%llu [+%llu]\n",
wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns,
wf_set.duty_length_ns, wf_set.period_length_ns, wf_set.duty_offset_ns);
}
return 0;
}
/**
* pwm_set_waveform_might_sleep - Apply a new waveform
* Cannot be used in atomic context.
* @pwm: PWM device
* @wf: The waveform to apply
* @exact: If true no rounding is allowed
*
* Typically a requested waveform cannot be implemented exactly, e.g. because
* you requested .period_length_ns = 100 ns, but the hardware can only set
* periods that are a multiple of 8.5 ns. With that hardware passing exact =
* true results in pwm_set_waveform_might_sleep() failing and returning 1. If
* exact = false you get a period of 93.5 ns (i.e. the biggest period not bigger
* than the requested value).
* Note that even with exact = true, some rounding by less than 1 is
* possible/needed. In the above example requesting .period_length_ns = 94 and
* exact = true, you get the hardware configured with period = 93.5 ns.
*/
int pwm_set_waveform_might_sleep(struct pwm_device *pwm,
const struct pwm_waveform *wf, bool exact)
{
struct pwm_chip *chip = pwm->chip;
int err;
might_sleep();
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && chip->atomic) {
/*
* Catch any drivers that have been marked as atomic but
* that will sleep anyway.
*/
non_block_start();
err = __pwm_set_waveform(pwm, wf, exact);
non_block_end();
} else {
err = __pwm_set_waveform(pwm, wf, exact);
}
return err;
}
EXPORT_SYMBOL_GPL(pwm_set_waveform_might_sleep);
static void pwm_apply_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 = { 0 }, s2 = { 0 };
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.
*/
err = chip->ops->get_state(chip, pwm, &s1);
trace_pwm_get(pwm, &s1, err);
if (err)
/* If that failed there isn't much to debug */
return;
/*
* 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(pwmchip_parent(chip), ".apply ignored .polarity\n");
if (state->enabled && s2.enabled &&
last->polarity == state->polarity &&
last->period > s2.period &&
last->period <= state->period)
dev_warn(pwmchip_parent(chip),
".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
state->period, s2.period, last->period);
/*
* Rounding period up is fine only if duty_cycle is 0 then, because a
* flat line doesn't have a characteristic period.
*/
if (state->enabled && s2.enabled && state->period < s2.period && s2.duty_cycle)
dev_warn(pwmchip_parent(chip),
".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(pwmchip_parent(chip),
".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 && s2.enabled && state->duty_cycle < s2.duty_cycle)
dev_warn(pwmchip_parent(chip),
".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(pwmchip_parent(chip),
"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);
trace_pwm_apply(pwm, &s1, err);
if (err) {
*last = s1;
dev_err(pwmchip_parent(chip), "failed to reapply current setting\n");
return;
}
*last = (struct pwm_state){ 0 };
err = chip->ops->get_state(chip, pwm, last);
trace_pwm_get(pwm, last, err);
if (err)
return;
/* 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(pwmchip_parent(chip),
".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);
}
}
static bool pwm_state_valid(const struct pwm_state *state)
{
/*
* For a disabled state all other state description is irrelevant and
* and supposed to be ignored. So also ignore any strange values and
* consider the state ok.
*/
if (state->enabled)
return true;
if (!state->period)
return false;
if (state->duty_cycle > state->period)
return false;
return true;
}
/**
* __pwm_apply() - atomically apply a new state to a PWM device
* @pwm: PWM device
* @state: new state to apply
*/
static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
{
struct pwm_chip *chip;
const struct pwm_ops *ops;
int err;
if (!pwm || !state)
return -EINVAL;
if (!pwm_state_valid(state)) {
/*
* Allow to transition from one invalid state to another.
* This ensures that you can e.g. change the polarity while
* the period is zero. (This happens on stm32 when the hardware
* is in its poweron default state.) This greatly simplifies
* working with the sysfs API where you can only change one
* parameter at a time.
*/
if (!pwm_state_valid(&pwm->state)) {
pwm->state = *state;
return 0;
}
return -EINVAL;
}
chip = pwm->chip;
ops = chip->ops;
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;
if (pwmchip_supports_waveform(chip)) {
struct pwm_waveform wf;
char wfhw[WFHWSIZE];
BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
pwm_state2wf(state, &wf);
/*
* The rounding is wrong here for states with inverted polarity.
* While .apply() rounds down duty_cycle (which represents the
* time from the start of the period to the inner edge),
* .round_waveform_tohw() rounds down the time the PWM is high.
* Can be fixed if the need arises, until reported otherwise
* let's assume that consumers don't care.
*/
err = __pwm_round_waveform_tohw(chip, pwm, &wf, &wfhw);
if (err) {
if (err > 0)
/*
* This signals an invalid request, typically
* the requested period (or duty_offset) is
* smaller than possible with the hardware.
*/
return -EINVAL;
return err;
}
if (IS_ENABLED(CONFIG_PWM_DEBUG)) {
struct pwm_waveform wf_rounded;
err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
if (err)
return err;
if (!pwm_check_rounding(&wf, &wf_rounded))
dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
wf.duty_length_ns, wf.period_length_ns, wf.duty_offset_ns,
wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
}
err = __pwm_write_waveform(chip, pwm, &wfhw);
if (err)
return err;
pwm->state = *state;
} else {
err = ops->apply(chip, pwm, state);
trace_pwm_apply(pwm, state, err);
if (err)
return err;
pwm->state = *state;
/*
* only do this after pwm->state was applied as some
* implementations of .get_state() depend on this
*/
pwm_apply_debug(pwm, state);
}
return 0;
}
/**
* pwm_apply_might_sleep() - atomically apply a new state to a PWM device
* Cannot be used in atomic context.
* @pwm: PWM device
* @state: new state to apply
*/
int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
{
int err;
struct pwm_chip *chip = pwm->chip;
/*
* 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_might_sleep() from atomic context
* is a bad idea. So make it explicit that calling this function might
* sleep.
*/
might_sleep();
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && chip->atomic) {
/*
* Catch any drivers that have been marked as atomic but
* that will sleep anyway.
*/
non_block_start();
err = __pwm_apply(pwm, state);
non_block_end();
} else {
err = __pwm_apply(pwm, state);
}
return err;
}
EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
/**
* pwm_apply_atomic() - apply a new state to a PWM device from atomic context
* Not all PWM devices support this function, check with pwm_might_sleep().
* @pwm: PWM device
* @state: new state to apply
*/
int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
{
struct pwm_chip *chip = pwm->chip;
WARN_ONCE(!chip->atomic,
"sleeping PWM driver used in atomic context\n");
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
return __pwm_apply(pwm, state);
}
EXPORT_SYMBOL_GPL(pwm_apply_atomic);
/**
* pwm_get_state_hw() - get the current PWM state from hardware
* @pwm: PWM device
* @state: state to fill with the current PWM state
*
* Similar to pwm_get_state() but reads the current PWM state from hardware
* instead of the requested state.
*
* Returns: 0 on success or a negative error code on failure.
* Context: May sleep.
*/
int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state)
{
struct pwm_chip *chip = pwm->chip;
const struct pwm_ops *ops = chip->ops;
int ret = -EOPNOTSUPP;
might_sleep();
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
if (pwmchip_supports_waveform(chip) && ops->read_waveform) {
char wfhw[WFHWSIZE];
struct pwm_waveform wf;
BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
ret = __pwm_read_waveform(chip, pwm, &wfhw);
if (ret)
return ret;
ret = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf);
if (ret)
return ret;
pwm_wf2state(&wf, state);
} else if (ops->get_state) {
ret = ops->get_state(chip, pwm, state);
trace_pwm_get(pwm, state, ret);
}
return ret;
}
EXPORT_SYMBOL_GPL(pwm_get_state_hw);
/**
* 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_might_sleep(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_might_sleep(pwm, &state);
}
EXPORT_SYMBOL_GPL(pwm_adjust_config);
/**
* 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.
*/
static int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
unsigned long timeout)
{
struct pwm_chip *chip = pwm->chip;
const struct pwm_ops *ops = chip->ops;
if (!ops->capture)
return -ENOSYS;
/*
* Holding the pwm_lock is probably not needed. If you use pwm_capture()
* and you're interested to speed it up, please convince yourself it's
* really not needed, test and then suggest a patch on the mailing list.
*/
guard(mutex)(&pwm_lock);
guard(pwmchip)(chip);
if (!chip->operational)
return -ENODEV;
return ops->capture(chip, pwm, result, timeout);
}
static struct pwm_chip *pwmchip_find_by_name(const char *name)
{
struct pwm_chip *chip;
unsigned long id, tmp;
if (!name)
return NULL;
guard(mutex)(&pwm_lock);
idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
if (device_match_name(pwmchip_parent(chip), name))
return chip;
}
return NULL;
}
static int pwm_device_request(struct pwm_device *pwm, const char *label)
{
int err;
struct pwm_chip *chip = pwm->chip;
const struct pwm_ops *ops = chip->ops;
if (test_bit(PWMF_REQUESTED, &pwm->flags))
return -EBUSY;
/*
* This function is called while holding pwm_lock. As .operational only
* changes while holding this lock, checking it here without holding the
* chip lock is fine.
*/
if (!chip->operational)
return -ENODEV;
if (!try_module_get(chip->owner))
return -ENODEV;
if (!get_device(&chip->dev)) {
err = -ENODEV;
goto err_get_device;
}
if (ops->request) {
err = ops->request(chip, pwm);
if (err) {
put_device(&chip->dev);
err_get_device:
module_put(chip->owner);
return err;
}
}
if (ops->read_waveform || ops->get_state) {
/*
* Zero-initialize state because most drivers are unaware of
* .usage_power. The other members of state are supposed to be
* set by lowlevel drivers. We still initialize the whole
* structure for simplicity even though this might paper over
* faulty implementations of .get_state().
*/
struct pwm_state state = { 0, };
err = pwm_get_state_hw(pwm, &state);
if (!err)
pwm->state = state;
if (IS_ENABLED(CONFIG_PWM_DEBUG))
pwm->last = pwm->state;
}
set_bit(PWMF_REQUESTED, &pwm->flags);
pwm->label = label;
return 0;
}
/**
* 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.
*/
static 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);
guard(mutex)(&pwm_lock);
pwm = &chip->pwms[index];
err = pwm_device_request(pwm, label);
if (err < 0)
return ERR_PTR(err);
return pwm;
}
struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
/* period in the second cell and flags in the third cell are optional */
if (args->args_count < 1)
return ERR_PTR(-EINVAL);
pwm = pwm_request_from_chip(chip, args->args[0], NULL);
if (IS_ERR(pwm))
return pwm;
if (args->args_count > 1)
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);
/*
* This callback is used for PXA PWM chips that only have a single PWM line.
* For such chips you could argue that passing the line number (i.e. the first
* parameter in the common case) is useless as it's always zero. So compared to
* the default xlate function of_pwm_xlate_with_flags() the first parameter is
* the default period and the second are flags.
*
* Note that if #pwm-cells = <3>, the semantic is the same as for
* of_pwm_xlate_with_flags() to allow converting the affected driver to
* #pwm-cells = <3> without breaking the legacy binding.
*
* Don't use for new drivers.
*/
struct pwm_device *
of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
if (args->args_count >= 3)
return of_pwm_xlate_with_flags(chip, args);
pwm = pwm_request_from_chip(chip, 0, NULL);
if (IS_ERR(pwm))
return pwm;
if (args->args_count > 0)
pwm->args.period = args->args[0];
pwm->args.polarity = PWM_POLARITY_NORMAL;
if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED)
pwm->args.polarity = PWM_POLARITY_INVERSED;
return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
struct pwm_export {
struct device pwm_dev;
struct pwm_device *pwm;
struct mutex lock;
struct pwm_state suspend;
};
static inline struct pwm_chip *pwmchip_from_dev(struct device *pwmchip_dev)
{
return container_of(pwmchip_dev, struct pwm_chip, dev);
}
static inline struct pwm_export *pwmexport_from_dev(struct device *pwm_dev)
{
return container_of(pwm_dev, struct pwm_export, pwm_dev);
}
static inline struct pwm_device *pwm_from_dev(struct device *pwm_dev)
{
struct pwm_export *export = pwmexport_from_dev(pwm_dev);
return export->pwm;
}
static ssize_t period_show(struct device *pwm_dev,
struct device_attribute *attr,
char *buf)
{
const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
struct pwm_state state;
pwm_get_state(pwm, &state);
return sysfs_emit(buf, "%llu\n", state.period);
}
static ssize_t period_store(struct device *pwm_dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct pwm_export *export = pwmexport_from_dev(pwm_dev);
struct pwm_device *pwm = export->pwm;
struct pwm_state state;
u64 val;
int ret;
ret = kstrtou64(buf, 0, &val);
if (ret)
return ret;
guard(mutex)(&export->lock);
pwm_get_state(pwm, &state);
state.period = val;
ret = pwm_apply_might_sleep(pwm, &state);
return ret ? : size;
}
static ssize_t duty_cycle_show(struct device *pwm_dev,
struct device_attribute *attr,
char *buf)
{
const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
struct pwm_state state;
pwm_get_state(pwm, &state);
return sysfs_emit(buf, "%llu\n", state.duty_cycle);
}
static ssize_t duty_cycle_store(struct device *pwm_dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct pwm_export *export = pwmexport_from_dev(pwm_dev);
struct pwm_device *pwm = export->pwm;
struct pwm_state state;
u64 val;
int ret;
ret = kstrtou64(buf, 0, &val);
if (ret)
return ret;
guard(mutex)(&export->lock);
pwm_get_state(pwm, &state);
state.duty_cycle = val;
ret = pwm_apply_might_sleep(pwm, &state);
return ret ? : size;
}
static ssize_t enable_show(struct device *pwm_dev,
struct device_attribute *attr,
char *buf)
{
const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
struct pwm_state state;
pwm_get_state(pwm, &state);
return sysfs_emit(buf, "%d\n", state.enabled);
}
static ssize_t enable_store(struct device *pwm_dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct pwm_export *export = pwmexport_from_dev(pwm_dev);
struct pwm_device *pwm = export->pwm;
struct pwm_state state;
int val, ret;
ret = kstrtoint(buf, 0, &val);
if (ret)
return ret;
guard(mutex)(&export->lock);
pwm_get_state(pwm, &state);
switch (val) {
case 0:
state.enabled = false;
break;
case 1:
state.enabled = true;
break;
default:
return -EINVAL;
}
ret = pwm_apply_might_sleep(pwm, &state);
return ret ? : size;
}
static ssize_t polarity_show(struct device *pwm_dev,
struct device_attribute *attr,
char *buf)
{
const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
const char *polarity = "unknown";
struct pwm_state state;
pwm_get_state(pwm, &state);
switch (state.polarity) {
case PWM_POLARITY_NORMAL:
polarity = "normal";
break;
case PWM_POLARITY_INVERSED:
polarity = "inversed";
break;
}
return sysfs_emit(buf, "%s\n", polarity);
}
static ssize_t polarity_store(struct device *pwm_dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct pwm_export *export = pwmexport_from_dev(pwm_dev);
struct pwm_device *pwm = export->pwm;
enum pwm_polarity polarity;
struct pwm_state state;
int ret;
if (sysfs_streq(buf, "normal"))
polarity = PWM_POLARITY_NORMAL;
else if (sysfs_streq(buf, "inversed"))
polarity = PWM_POLARITY_INVERSED;
else
return -EINVAL;
guard(mutex)(&export->lock);
pwm_get_state(pwm, &state);
state.polarity = polarity;
ret = pwm_apply_might_sleep(pwm, &state);
return ret ? : size;
}
static ssize_t capture_show(struct device *pwm_dev,
struct device_attribute *attr,
char *buf)
{
struct pwm_device *pwm = pwm_from_dev(pwm_dev);
struct pwm_capture result;
int ret;
ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
if (ret)
return ret;
return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle);
}
static DEVICE_ATTR_RW(period);
static DEVICE_ATTR_RW(duty_cycle);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(polarity);
static DEVICE_ATTR_RO(capture);
static struct attribute *pwm_attrs[] = {
&dev_attr_period.attr,
&dev_attr_duty_cycle.attr,
&dev_attr_enable.attr,
&dev_attr_polarity.attr,
&dev_attr_capture.attr,
NULL
};
ATTRIBUTE_GROUPS(pwm);
static void pwm_export_release(struct device *pwm_dev)
{
struct pwm_export *export = pwmexport_from_dev(pwm_dev);
kfree(export);
}
static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm)
{
struct pwm_export *export;
char *pwm_prop[2];
int ret;
if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
return -EBUSY;
export = kzalloc(sizeof(*export), GFP_KERNEL);
if (!export) {
clear_bit(PWMF_EXPORTED, &pwm->flags);
return -ENOMEM;
}
export->pwm = pwm;
mutex_init(&export->lock);
export->pwm_dev.release = pwm_export_release;
export->pwm_dev.parent = pwmchip_dev;
export->pwm_dev.devt = MKDEV(0, 0);
export->pwm_dev.groups = pwm_groups;
dev_set_name(&export->pwm_dev, "pwm%u", pwm->hwpwm);
ret = device_register(&export->pwm_dev);
if (ret) {
clear_bit(PWMF_EXPORTED, &pwm->flags);
put_device(&export->pwm_dev);
export = NULL;
return ret;
}
pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
pwm_prop[1] = NULL;
kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
kfree(pwm_prop[0]);
return 0;
}
static int pwm_unexport_match(struct device *pwm_dev, const void *data)
{
return pwm_from_dev(pwm_dev) == data;
}
static int pwm_unexport_child(struct device *pwmchip_dev, struct pwm_device *pwm)
{
struct device *pwm_dev;
char *pwm_prop[2];
if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
return -ENODEV;
pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
if (!pwm_dev)
return -ENODEV;
pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
pwm_prop[1] = NULL;
kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
kfree(pwm_prop[0]);
/* for device_find_child() */
put_device(pwm_dev);
device_unregister(pwm_dev);
pwm_put(pwm);
return 0;
}
static ssize_t export_store(struct device *pwmchip_dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
struct pwm_device *pwm;
unsigned int hwpwm;
int ret;
ret = kstrtouint(buf, 0, &hwpwm);
if (ret < 0)
return ret;
if (hwpwm >= chip->npwm)
return -ENODEV;
pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
if (IS_ERR(pwm))
return PTR_ERR(pwm);
ret = pwm_export_child(pwmchip_dev, pwm);
if (ret < 0)
pwm_put(pwm);
return ret ? : len;
}
static DEVICE_ATTR_WO(export);
static ssize_t unexport_store(struct device *pwmchip_dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
unsigned int hwpwm;
int ret;
ret = kstrtouint(buf, 0, &hwpwm);
if (ret < 0)
return ret;
if (hwpwm >= chip->npwm)
return -ENODEV;
ret = pwm_unexport_child(pwmchip_dev, &chip->pwms[hwpwm]);
return ret ? : len;
}
static DEVICE_ATTR_WO(unexport);
static ssize_t npwm_show(struct device *pwmchip_dev, struct device_attribute *attr,
char *buf)
{
const struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
return sysfs_emit(buf, "%u\n", chip->npwm);
}
static DEVICE_ATTR_RO(npwm);
static struct attribute *pwm_chip_attrs[] = {
&dev_attr_export.attr,
&dev_attr_unexport.attr,
&dev_attr_npwm.attr,
NULL,
};
ATTRIBUTE_GROUPS(pwm_chip);
/* takes export->lock on success */
static struct pwm_export *pwm_class_get_state(struct device *pwmchip_dev,
struct pwm_device *pwm,
struct pwm_state *state)
{
struct device *pwm_dev;
struct pwm_export *export;
if (!test_bit(PWMF_EXPORTED, &pwm->flags))
return NULL;
pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
if (!pwm_dev)
return NULL;
export = pwmexport_from_dev(pwm_dev);
put_device(pwm_dev); /* for device_find_child() */
mutex_lock(&export->lock);
pwm_get_state(pwm, state);
return export;
}
static int pwm_class_apply_state(struct pwm_export *export,
struct pwm_device *pwm,
struct pwm_state *state)
{
int ret = pwm_apply_might_sleep(pwm, state);
/* release lock taken in pwm_class_get_state */
mutex_unlock(&export->lock);
return ret;
}
static int pwm_class_resume_npwm(struct device *pwmchip_dev, unsigned int npwm)
{
struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
unsigned int i;
int ret = 0;
for (i = 0; i < npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
struct pwm_state state;
struct pwm_export *export;
export = pwm_class_get_state(pwmchip_dev, pwm, &state);
if (!export)
continue;
/* If pwmchip was not enabled before suspend, do nothing. */
if (!export->suspend.enabled) {
/* release lock taken in pwm_class_get_state */
mutex_unlock(&export->lock);
continue;
}
state.enabled = export->suspend.enabled;
ret = pwm_class_apply_state(export, pwm, &state);
if (ret < 0)
break;
}
return ret;
}
static int pwm_class_suspend(struct device *pwmchip_dev)
{
struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
unsigned int i;
int ret = 0;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
struct pwm_state state;
struct pwm_export *export;
export = pwm_class_get_state(pwmchip_dev, pwm, &state);
if (!export)
continue;
/*
* If pwmchip was not enabled before suspend, save
* state for resume time and do nothing else.
*/
export->suspend = state;
if (!state.enabled) {
/* release lock taken in pwm_class_get_state */
mutex_unlock(&export->lock);
continue;
}
state.enabled = false;
ret = pwm_class_apply_state(export, pwm, &state);
if (ret < 0) {
/*
* roll back the PWM devices that were disabled by
* this suspend function.
*/
pwm_class_resume_npwm(pwmchip_dev, i);
break;
}
}
return ret;
}
static int pwm_class_resume(struct device *pwmchip_dev)
{
struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
return pwm_class_resume_npwm(pwmchip_dev, chip->npwm);
}
static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
static struct class pwm_class = {
.name = "pwm",
.dev_groups = pwm_chip_groups,
.pm = pm_sleep_ptr(&pwm_class_pm_ops),
};
static void pwmchip_sysfs_unexport(struct pwm_chip *chip)
{
unsigned int i;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
if (test_bit(PWMF_EXPORTED, &pwm->flags))
pwm_unexport_child(&chip->dev, pwm);
}
}
#define PWMCHIP_ALIGN ARCH_DMA_MINALIGN
static void *pwmchip_priv(struct pwm_chip *chip)
{
return (void *)chip + ALIGN(struct_size(chip, pwms, chip->npwm), PWMCHIP_ALIGN);
}
/* This is the counterpart to pwmchip_alloc() */
void pwmchip_put(struct pwm_chip *chip)
{
put_device(&chip->dev);
}
EXPORT_SYMBOL_GPL(pwmchip_put);
static void pwmchip_release(struct device *pwmchip_dev)
{
struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
kfree(chip);
}
struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
{
struct pwm_chip *chip;
struct device *pwmchip_dev;
size_t alloc_size;
unsigned int i;
alloc_size = size_add(ALIGN(struct_size(chip, pwms, npwm), PWMCHIP_ALIGN),
sizeof_priv);
chip = kzalloc(alloc_size, GFP_KERNEL);
if (!chip)
return ERR_PTR(-ENOMEM);
chip->npwm = npwm;
chip->uses_pwmchip_alloc = true;
chip->operational = false;
pwmchip_dev = &chip->dev;
device_initialize(pwmchip_dev);
pwmchip_dev->class = &pwm_class;
pwmchip_dev->parent = parent;
pwmchip_dev->release = pwmchip_release;
pwmchip_set_drvdata(chip, pwmchip_priv(chip));
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
pwm->chip = chip;
pwm->hwpwm = i;
}
return chip;
}
EXPORT_SYMBOL_GPL(pwmchip_alloc);
static void devm_pwmchip_put(void *data)
{
struct pwm_chip *chip = data;
pwmchip_put(chip);
}
struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
{
struct pwm_chip *chip;
int ret;
chip = pwmchip_alloc(parent, npwm, sizeof_priv);
if (IS_ERR(chip))
return chip;
ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip);
if (ret)
return ERR_PTR(ret);
return chip;
}
EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);
static void of_pwmchip_add(struct pwm_chip *chip)
{
if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node)
return;
if (!chip->of_xlate)
chip->of_xlate = of_pwm_xlate_with_flags;
of_node_get(pwmchip_parent(chip)->of_node);
}
static void of_pwmchip_remove(struct pwm_chip *chip)
{
if (pwmchip_parent(chip))
of_node_put(pwmchip_parent(chip)->of_node);
}
static bool pwm_ops_check(const struct pwm_chip *chip)
{
const struct pwm_ops *ops = chip->ops;
if (ops->write_waveform) {
if (!ops->round_waveform_tohw ||
!ops->round_waveform_fromhw ||
!ops->write_waveform)
return false;
if (WFHWSIZE < ops->sizeof_wfhw) {
dev_warn(pwmchip_parent(chip), "WFHWSIZE < %zu\n", ops->sizeof_wfhw);
return false;
}
} else {
if (!ops->apply)
return false;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
dev_warn(pwmchip_parent(chip),
"Please implement the .get_state() callback\n");
}
return true;
}
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(pwmchip_parent(pwm->chip),
"No consumer device specified to create a link to\n");
return NULL;
}
dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER);
if (!dl) {
dev_err(dev, "failed to create device link to %s\n",
dev_name(pwmchip_parent(pwm->chip)));
return ERR_PTR(-EINVAL);
}
return dl;
}
static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
{
struct pwm_chip *chip;
unsigned long id, tmp;
guard(mutex)(&pwm_lock);
idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode))
return chip;
return ERR_PTR(-EPROBE_DEFER);
}
/**
* 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 *chip;
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_map(np, "pwms", "pwm", index, &args);
if (err) {
pr_err("%s(): can't parse \"pwms\" property\n", __func__);
return ERR_PTR(err);
}
chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
if (IS_ERR(chip)) {
if (PTR_ERR(chip) != -EPROBE_DEFER)
pr_err("%s(): PWM chip not found\n", __func__);
pwm = ERR_CAST(chip);
goto put;
}
pwm = chip->of_xlate(chip, &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_put(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;
}
static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list);
/**
* 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.
*/
scoped_guard(mutex, &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;
}
}
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_put(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)
{
struct pwm_chip *chip;
if (!pwm)
return;
chip = pwm->chip;
guard(mutex)(&pwm_lock);
/*
* Trigger a warning if a consumer called pwm_put() twice.
* If the chip isn't operational, PWMF_REQUESTED was already cleared in
* pwmchip_remove(). So don't warn in this case.
*/
if (chip->operational && !test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
pr_warn("PWM device already freed\n");
return;
}
if (chip->operational && chip->ops->free)
pwm->chip->ops->free(pwm->chip, pwm);
pwm->label = NULL;
put_device(&chip->dev);
module_put(chip->owner);
}
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);
/**
* __pwmchip_add() - register a new PWM chip
* @chip: the PWM chip to add
* @owner: reference to the module providing the chip.
*
* Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
* pwmchip_add wrapper to do this right.
*
* Returns: 0 on success or a negative error code on failure.
*/
int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
{
int ret;
if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm)
return -EINVAL;
/*
* a struct pwm_chip must be allocated using (devm_)pwmchip_alloc,
* otherwise the embedded struct device might disappear too early
* resulting in memory corruption.
* Catch drivers that were not converted appropriately.
*/
if (!chip->uses_pwmchip_alloc)
return -EINVAL;
if (!pwm_ops_check(chip))
return -EINVAL;
chip->owner = owner;
if (chip->atomic)
spin_lock_init(&chip->atomic_lock);
else
mutex_init(&chip->nonatomic_lock);
guard(mutex)(&pwm_lock);
ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
if (ret < 0)
return ret;
chip->id = ret;
dev_set_name(&chip->dev, "pwmchip%u", chip->id);
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_add(chip);
scoped_guard(pwmchip, chip)
chip->operational = true;
ret = device_add(&chip->dev);
if (ret)
goto err_device_add;
return 0;
err_device_add:
scoped_guard(pwmchip, chip)
chip->operational = false;
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_remove(chip);
idr_remove(&pwm_chips, chip->id);
return ret;
}
EXPORT_SYMBOL_GPL(__pwmchip_add);
/**
* pwmchip_remove() - remove a PWM chip
* @chip: the PWM chip to remove
*
* Removes a PWM chip.
*/
void pwmchip_remove(struct pwm_chip *chip)
{
pwmchip_sysfs_unexport(chip);
scoped_guard(mutex, &pwm_lock) {
unsigned int i;
scoped_guard(pwmchip, chip)
chip->operational = false;
for (i = 0; i < chip->npwm; ++i) {
struct pwm_device *pwm = &chip->pwms[i];
if (test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
dev_warn(&chip->dev, "Freeing requested PWM #%u\n", i);
if (pwm->chip->ops->free)
pwm->chip->ops->free(pwm->chip, pwm);
}
}
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_remove(chip);
idr_remove(&pwm_chips, chip->id);
}
device_del(&chip->dev);
}
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, struct module *owner)
{
int ret;
ret = __pwmchip_add(chip, owner);
if (ret)
return ret;
return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
}
EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
/**
* 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)
{
guard(mutex)(&pwm_lookup_lock);
while (num--) {
list_add_tail(&table->list, &pwm_lookup_list);
table++;
}
}
/**
* 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)
{
guard(mutex)(&pwm_lookup_lock);
while (num--) {
list_del(&table->list);
table++;
}
}
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)
{
unsigned long id = *pos;
void *ret;
mutex_lock(&pwm_lock);
s->private = "";
ret = idr_get_next_ul(&pwm_chips, &id);
*pos = id;
return ret;
}
static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
unsigned long id = *pos + 1;
void *ret;
s->private = "\n";
ret = idr_get_next_ul(&pwm_chips, &id);
*pos = id;
return ret;
}
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 = v;
seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
(char *)s->private, chip->id,
pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus",
dev_name(pwmchip_parent(chip)), 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_init(void)
{
int ret;
ret = class_register(&pwm_class);
if (ret) {
pr_err("Failed to initialize PWM class (%pe)\n", ERR_PTR(ret));
return ret;
}
if (IS_ENABLED(CONFIG_DEBUG_FS))
debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
return 0;
}
subsys_initcall(pwm_init);