// SPDX-License-Identifier: GPL-2.0-or-later /* * Generic pwmlib implementation * * Copyright (C) 2011 Sascha Hauer * Copyright (C) 2011-2012 Avionic Design GmbH */ #define DEFAULT_SYMBOL_NAMESPACE "PWM" #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include /* 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 (!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); 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 (!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 (ops->write_waveform) { 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 (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); struct pwm_device * of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args) { struct pwm_device *pwm; 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, 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(np, "pwms", "#pwm-cells", 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 () * { , , [, ]}} * * 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);