diff options
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 885 |
1 files changed, 727 insertions, 158 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 6e752e148b98..9c733877e98e 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -31,6 +31,397 @@ 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) { @@ -75,7 +466,7 @@ static void pwm_apply_debug(struct pwm_device *pwm, state->duty_cycle < state->period) dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n"); - if (state->enabled && + if (state->enabled && s2.enabled && last->polarity == state->polarity && last->period > s2.period && last->period <= state->period) @@ -83,7 +474,11 @@ static void pwm_apply_debug(struct pwm_device *pwm, ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n", state->period, s2.period, last->period); - if (state->enabled && state->period < s2.period) + /* + * 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); @@ -99,7 +494,7 @@ static void pwm_apply_debug(struct pwm_device *pwm, s2.duty_cycle, s2.period, last->duty_cycle, last->period); - if (state->enabled && state->duty_cycle < s2.duty_cycle) + 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, @@ -164,6 +559,7 @@ static bool pwm_state_valid(const struct pwm_state *state) 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) @@ -187,6 +583,7 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) } chip = pwm->chip; + ops = chip->ops; if (state->period == pwm->state.period && state->duty_cycle == pwm->state.duty_cycle && @@ -195,18 +592,69 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) state->usage_power == pwm->state.usage_power) return 0; - err = chip->ops->apply(chip, pwm, state); - trace_pwm_apply(pwm, state, err); - if (err) - return err; + if (ops->write_waveform) { + struct pwm_waveform wf; + char wfhw[WFHWSIZE]; - pwm->state = *state; + BUG_ON(WFHWSIZE < ops->sizeof_wfhw); - /* - * only do this after pwm->state was applied as some - * implementations of .get_state depend on this - */ - pwm_apply_debug(pwm, state); + 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; } @@ -220,6 +668,7 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) 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 @@ -230,7 +679,12 @@ int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state) */ might_sleep(); - if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) { + 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. @@ -254,14 +708,70 @@ EXPORT_SYMBOL_GPL(pwm_apply_might_sleep); */ int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state) { - WARN_ONCE(!pwm->chip->atomic, + 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 * @@ -334,8 +844,18 @@ static int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, 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); } @@ -350,9 +870,7 @@ static struct pwm_chip *pwmchip_find_by_name(const char *name) guard(mutex)(&pwm_lock); idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) { - const char *chip_name = dev_name(pwmchip_parent(chip)); - - if (chip_name && strcmp(chip_name, name) == 0) + if (device_match_name(pwmchip_parent(chip), name)) return chip; } @@ -368,6 +886,14 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) 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; @@ -386,7 +912,7 @@ err_get_device: } } - if (ops->get_state) { + 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 @@ -396,9 +922,7 @@ err_get_device: */ struct pwm_state state = { 0, }; - err = ops->get_state(chip, pwm, &state); - trace_pwm_get(pwm, &state, err); - + err = pwm_get_state_hw(pwm, &state); if (!err) pwm->state = state; @@ -1020,6 +1544,7 @@ struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t chip->npwm = npwm; chip->uses_pwmchip_alloc = true; + chip->operational = false; pwmchip_dev = &chip->dev; device_initialize(pwmchip_dev); @@ -1084,114 +1609,27 @@ static bool pwm_ops_check(const struct pwm_chip *chip) { const struct pwm_ops *ops = chip->ops; - if (!ops->apply) - return false; - - if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state) - dev_warn(pwmchip_parent(chip), - "Please implement the .get_state() callback\n"); - - return true; -} - -/** - * __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; - - 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); - - ret = device_add(&chip->dev); - if (ret) - goto err_device_add; - - return 0; - -err_device_add: - 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); - - if (IS_ENABLED(CONFIG_OF)) - of_pwmchip_remove(chip); - - scoped_guard(mutex, &pwm_lock) - 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); -} + if (ops->write_waveform) { + if (!ops->round_waveform_tohw || + !ops->round_waveform_fromhw || + !ops->write_waveform) + return false; -int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner) -{ - int ret; + if (WFHWSIZE < ops->sizeof_wfhw) { + dev_warn(pwmchip_parent(chip), "WFHWSIZE < %zu\n", ops->sizeof_wfhw); + return false; + } + } else { + if (!ops->apply) + return false; - ret = __pwmchip_add(chip, owner); - if (ret) - return ret; + if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state) + dev_warn(pwmchip_parent(chip), + "Please implement the .get_state() callback\n"); + } - return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip); + return true; } -EXPORT_SYMBOL_GPL(__devm_pwmchip_add); static struct device_link *pwm_device_link_add(struct device *dev, struct pwm_device *pwm) @@ -1371,36 +1809,6 @@ static DEFINE_MUTEX(pwm_lookup_lock); static LIST_HEAD(pwm_lookup_list); /** - * 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++; - } -} - -/** * pwm_get() - look up and request a PWM device * @dev: device for PWM consumer * @con_id: consumer name @@ -1538,12 +1946,17 @@ void pwm_put(struct pwm_device *pwm) guard(mutex)(&pwm_lock); - if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { + /* + * 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->ops->free) + if (chip->operational && chip->ops->free) pwm->chip->ops->free(pwm->chip, pwm); pwm->label = NULL; @@ -1621,6 +2034,162 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev, } 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; |