|  | // SPDX-License-Identifier: GPL-2.0 | 
|  | // | 
|  | // Copyright (C) 2021 ROHM Semiconductors | 
|  | // regulator IRQ based event notification helpers | 
|  | // | 
|  | // Logic has been partially adapted from qcom-labibb driver. | 
|  | // | 
|  | // Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> | 
|  |  | 
|  | #include <linux/device.h> | 
|  | #include <linux/err.h> | 
|  | #include <linux/interrupt.h> | 
|  | #include <linux/kernel.h> | 
|  | #include <linux/reboot.h> | 
|  | #include <linux/regmap.h> | 
|  | #include <linux/slab.h> | 
|  | #include <linux/spinlock.h> | 
|  | #include <linux/regulator/driver.h> | 
|  |  | 
|  | #include "internal.h" | 
|  |  | 
|  | #define REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS 10000 | 
|  |  | 
|  | struct regulator_irq { | 
|  | struct regulator_irq_data rdata; | 
|  | struct regulator_irq_desc desc; | 
|  | int irq; | 
|  | int retry_cnt; | 
|  | struct delayed_work isr_work; | 
|  | }; | 
|  |  | 
|  | /* | 
|  | * Should only be called from threaded handler to prevent potential deadlock | 
|  | */ | 
|  | static void rdev_flag_err(struct regulator_dev *rdev, int err) | 
|  | { | 
|  | spin_lock(&rdev->err_lock); | 
|  | rdev->cached_err |= err; | 
|  | spin_unlock(&rdev->err_lock); | 
|  | } | 
|  |  | 
|  | static void rdev_clear_err(struct regulator_dev *rdev, int err) | 
|  | { | 
|  | spin_lock(&rdev->err_lock); | 
|  | rdev->cached_err &= ~err; | 
|  | spin_unlock(&rdev->err_lock); | 
|  | } | 
|  |  | 
|  | static void regulator_notifier_isr_work(struct work_struct *work) | 
|  | { | 
|  | struct regulator_irq *h; | 
|  | struct regulator_irq_desc *d; | 
|  | struct regulator_irq_data *rid; | 
|  | int ret = 0; | 
|  | int tmo, i; | 
|  | int num_rdevs; | 
|  |  | 
|  | h = container_of(work, struct regulator_irq, | 
|  | isr_work.work); | 
|  | d = &h->desc; | 
|  | rid = &h->rdata; | 
|  | num_rdevs = rid->num_states; | 
|  |  | 
|  | reread: | 
|  | if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) { | 
|  | if (!d->die) | 
|  | return hw_protection_shutdown("Regulator HW failure? - no IC recovery", | 
|  | REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); | 
|  | ret = d->die(rid); | 
|  | /* | 
|  | * If the 'last resort' IC recovery failed we will have | 
|  | * nothing else left to do... | 
|  | */ | 
|  | if (ret) | 
|  | return hw_protection_shutdown("Regulator HW failure. IC recovery failed", | 
|  | REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); | 
|  |  | 
|  | /* | 
|  | * If h->die() was implemented we assume recovery has been | 
|  | * attempted (probably regulator was shut down) and we | 
|  | * just enable IRQ and bail-out. | 
|  | */ | 
|  | goto enable_out; | 
|  | } | 
|  | if (d->renable) { | 
|  | ret = d->renable(rid); | 
|  |  | 
|  | if (ret == REGULATOR_FAILED_RETRY) { | 
|  | /* Driver could not get current status */ | 
|  | h->retry_cnt++; | 
|  | if (!d->reread_ms) | 
|  | goto reread; | 
|  |  | 
|  | tmo = d->reread_ms; | 
|  | goto reschedule; | 
|  | } | 
|  |  | 
|  | if (ret) { | 
|  | /* | 
|  | * IC status reading succeeded. update error info | 
|  | * just in case the renable changed it. | 
|  | */ | 
|  | for (i = 0; i < num_rdevs; i++) { | 
|  | struct regulator_err_state *stat; | 
|  | struct regulator_dev *rdev; | 
|  |  | 
|  | stat = &rid->states[i]; | 
|  | rdev = stat->rdev; | 
|  | rdev_clear_err(rdev, (~stat->errors) & | 
|  | stat->possible_errs); | 
|  | } | 
|  | h->retry_cnt++; | 
|  | /* | 
|  | * The IC indicated problem is still ON - no point in | 
|  | * re-enabling the IRQ. Retry later. | 
|  | */ | 
|  | tmo = d->irq_off_ms; | 
|  | goto reschedule; | 
|  | } | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Either IC reported problem cleared or no status checker was provided. | 
|  | * If problems are gone - good. If not - then the IRQ will fire again | 
|  | * and we'll have a new nice loop. In any case we should clear error | 
|  | * flags here and re-enable IRQs. | 
|  | */ | 
|  | for (i = 0; i < num_rdevs; i++) { | 
|  | struct regulator_err_state *stat; | 
|  | struct regulator_dev *rdev; | 
|  |  | 
|  | stat = &rid->states[i]; | 
|  | rdev = stat->rdev; | 
|  | rdev_clear_err(rdev, stat->possible_errs); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Things have been seemingly successful => zero retry-counter. | 
|  | */ | 
|  | h->retry_cnt = 0; | 
|  |  | 
|  | enable_out: | 
|  | enable_irq(h->irq); | 
|  |  | 
|  | return; | 
|  |  | 
|  | reschedule: | 
|  | if (!d->high_prio) | 
|  | mod_delayed_work(system_wq, &h->isr_work, | 
|  | msecs_to_jiffies(tmo)); | 
|  | else | 
|  | mod_delayed_work(system_highpri_wq, &h->isr_work, | 
|  | msecs_to_jiffies(tmo)); | 
|  | } | 
|  |  | 
|  | static irqreturn_t regulator_notifier_isr(int irq, void *data) | 
|  | { | 
|  | struct regulator_irq *h = data; | 
|  | struct regulator_irq_desc *d; | 
|  | struct regulator_irq_data *rid; | 
|  | unsigned long rdev_map = 0; | 
|  | int num_rdevs; | 
|  | int ret, i; | 
|  |  | 
|  | d = &h->desc; | 
|  | rid = &h->rdata; | 
|  | num_rdevs = rid->num_states; | 
|  |  | 
|  | if (d->fatal_cnt) | 
|  | h->retry_cnt++; | 
|  |  | 
|  | /* | 
|  | * we spare a few cycles by not clearing statuses prior to this call. | 
|  | * The IC driver must initialize the status buffers for rdevs | 
|  | * which it indicates having active events via rdev_map. | 
|  | * | 
|  | * Maybe we should just to be on a safer side(?) | 
|  | */ | 
|  | ret = d->map_event(irq, rid, &rdev_map); | 
|  |  | 
|  | /* | 
|  | * If status reading fails (which is unlikely) we don't ack/disable | 
|  | * IRQ but just increase fail count and retry when IRQ fires again. | 
|  | * If retry_count exceeds the given safety limit we call IC specific die | 
|  | * handler which can try disabling regulator(s). | 
|  | * | 
|  | * If no die handler is given we will just bug() as a last resort. | 
|  | * | 
|  | * We could try disabling all associated rdevs - but we might shoot | 
|  | * ourselves in the head and leave the problematic regulator enabled. So | 
|  | * if IC has no die-handler populated we just assume the regulator | 
|  | * can't be disabled. | 
|  | */ | 
|  | if (unlikely(ret == REGULATOR_FAILED_RETRY)) | 
|  | goto fail_out; | 
|  |  | 
|  | h->retry_cnt = 0; | 
|  | /* | 
|  | * Let's not disable IRQ if there were no status bits for us. We'd | 
|  | * better leave spurious IRQ handling to genirq | 
|  | */ | 
|  | if (ret || !rdev_map) | 
|  | return IRQ_NONE; | 
|  |  | 
|  | /* | 
|  | * Some events are bogus if the regulator is disabled. Skip such events | 
|  | * if all relevant regulators are disabled | 
|  | */ | 
|  | if (d->skip_off) { | 
|  | for_each_set_bit(i, &rdev_map, num_rdevs) { | 
|  | struct regulator_dev *rdev; | 
|  | const struct regulator_ops *ops; | 
|  |  | 
|  | rdev = rid->states[i].rdev; | 
|  | ops = rdev->desc->ops; | 
|  |  | 
|  | /* | 
|  | * If any of the flagged regulators is enabled we do | 
|  | * handle this | 
|  | */ | 
|  | if (ops->is_enabled(rdev)) | 
|  | break; | 
|  | } | 
|  | if (i == num_rdevs) | 
|  | return IRQ_NONE; | 
|  | } | 
|  |  | 
|  | /* Disable IRQ if HW keeps line asserted */ | 
|  | if (d->irq_off_ms) | 
|  | disable_irq_nosync(irq); | 
|  |  | 
|  | /* | 
|  | * IRQ seems to be for us. Let's fire correct notifiers / store error | 
|  | * flags | 
|  | */ | 
|  | for_each_set_bit(i, &rdev_map, num_rdevs) { | 
|  | struct regulator_err_state *stat; | 
|  | struct regulator_dev *rdev; | 
|  |  | 
|  | stat = &rid->states[i]; | 
|  | rdev = stat->rdev; | 
|  |  | 
|  | rdev_dbg(rdev, "Sending regulator notification EVT 0x%lx\n", | 
|  | stat->notifs); | 
|  |  | 
|  | regulator_notifier_call_chain(rdev, stat->notifs, NULL); | 
|  | rdev_flag_err(rdev, stat->errors); | 
|  | } | 
|  |  | 
|  | if (d->irq_off_ms) { | 
|  | if (!d->high_prio) | 
|  | schedule_delayed_work(&h->isr_work, | 
|  | msecs_to_jiffies(d->irq_off_ms)); | 
|  | else | 
|  | mod_delayed_work(system_highpri_wq, | 
|  | &h->isr_work, | 
|  | msecs_to_jiffies(d->irq_off_ms)); | 
|  | } | 
|  |  | 
|  | return IRQ_HANDLED; | 
|  |  | 
|  | fail_out: | 
|  | if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) { | 
|  | /* If we have no recovery, just try shut down straight away */ | 
|  | if (!d->die) { | 
|  | hw_protection_shutdown("Regulator failure. Retry count exceeded", | 
|  | REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); | 
|  | } else { | 
|  | ret = d->die(rid); | 
|  | /* If die() failed shut down as a last attempt to save the HW */ | 
|  | if (ret) | 
|  | hw_protection_shutdown("Regulator failure. Recovery failed", | 
|  | REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); | 
|  | } | 
|  | } | 
|  |  | 
|  | return IRQ_NONE; | 
|  | } | 
|  |  | 
|  | static int init_rdev_state(struct device *dev, struct regulator_irq *h, | 
|  | struct regulator_dev **rdev, int common_err, | 
|  | int *rdev_err, int rdev_amount) | 
|  | { | 
|  | int i; | 
|  |  | 
|  | h->rdata.states = devm_kzalloc(dev, sizeof(*h->rdata.states) * | 
|  | rdev_amount, GFP_KERNEL); | 
|  | if (!h->rdata.states) | 
|  | return -ENOMEM; | 
|  |  | 
|  | h->rdata.num_states = rdev_amount; | 
|  | h->rdata.data = h->desc.data; | 
|  |  | 
|  | for (i = 0; i < rdev_amount; i++) { | 
|  | h->rdata.states[i].possible_errs = common_err; | 
|  | if (rdev_err) | 
|  | h->rdata.states[i].possible_errs |= *rdev_err++; | 
|  | h->rdata.states[i].rdev = *rdev++; | 
|  | } | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static void init_rdev_errors(struct regulator_irq *h) | 
|  | { | 
|  | int i; | 
|  |  | 
|  | for (i = 0; i < h->rdata.num_states; i++) | 
|  | if (h->rdata.states[i].possible_errs) | 
|  | h->rdata.states[i].rdev->use_cached_err = true; | 
|  | } | 
|  |  | 
|  | /** | 
|  | * regulator_irq_helper - register IRQ based regulator event/error notifier | 
|  | * | 
|  | * @dev:		device providing the IRQs | 
|  | * @d:			IRQ helper descriptor. | 
|  | * @irq:		IRQ used to inform events/errors to be notified. | 
|  | * @irq_flags:		Extra IRQ flags to be OR'ed with the default | 
|  | *			IRQF_ONESHOT when requesting the (threaded) irq. | 
|  | * @common_errs:	Errors which can be flagged by this IRQ for all rdevs. | 
|  | *			When IRQ is re-enabled these errors will be cleared | 
|  | *			from all associated regulators | 
|  | * @per_rdev_errs:	Optional error flag array describing errors specific | 
|  | *			for only some of the regulators. These errors will be | 
|  | *			or'ed with common errors. If this is given the array | 
|  | *			should contain rdev_amount flags. Can be set to NULL | 
|  | *			if there is no regulator specific error flags for this | 
|  | *			IRQ. | 
|  | * @rdev:		Array of pointers to regulators associated with this | 
|  | *			IRQ. | 
|  | * @rdev_amount:	Amount of regulators associated with this IRQ. | 
|  | * | 
|  | * Return: handle to irq_helper or an ERR_PTR() encoded error code. | 
|  | */ | 
|  | void *regulator_irq_helper(struct device *dev, | 
|  | const struct regulator_irq_desc *d, int irq, | 
|  | int irq_flags, int common_errs, int *per_rdev_errs, | 
|  | struct regulator_dev **rdev, int rdev_amount) | 
|  | { | 
|  | struct regulator_irq *h; | 
|  | int ret; | 
|  |  | 
|  | if (!rdev_amount || !d || !d->map_event || !d->name) | 
|  | return ERR_PTR(-EINVAL); | 
|  |  | 
|  | h = devm_kzalloc(dev, sizeof(*h), GFP_KERNEL); | 
|  | if (!h) | 
|  | return ERR_PTR(-ENOMEM); | 
|  |  | 
|  | h->irq = irq; | 
|  | h->desc = *d; | 
|  |  | 
|  | ret = init_rdev_state(dev, h, rdev, common_errs, per_rdev_errs, | 
|  | rdev_amount); | 
|  | if (ret) | 
|  | return ERR_PTR(ret); | 
|  |  | 
|  | init_rdev_errors(h); | 
|  |  | 
|  | if (h->desc.irq_off_ms) | 
|  | INIT_DELAYED_WORK(&h->isr_work, regulator_notifier_isr_work); | 
|  |  | 
|  | ret = request_threaded_irq(h->irq, NULL, regulator_notifier_isr, | 
|  | IRQF_ONESHOT | irq_flags, h->desc.name, h); | 
|  | if (ret) { | 
|  | dev_err(dev, "Failed to request IRQ %d\n", irq); | 
|  |  | 
|  | return ERR_PTR(ret); | 
|  | } | 
|  |  | 
|  | return h; | 
|  | } | 
|  | EXPORT_SYMBOL_GPL(regulator_irq_helper); | 
|  |  | 
|  | /** | 
|  | * regulator_irq_helper_cancel - drop IRQ based regulator event/error notifier | 
|  | * | 
|  | * @handle:		Pointer to handle returned by a successful call to | 
|  | *			regulator_irq_helper(). Will be NULLed upon return. | 
|  | * | 
|  | * The associated IRQ is released and work is cancelled when the function | 
|  | * returns. | 
|  | */ | 
|  | void regulator_irq_helper_cancel(void **handle) | 
|  | { | 
|  | if (handle && *handle) { | 
|  | struct regulator_irq *h = *handle; | 
|  |  | 
|  | free_irq(h->irq, h); | 
|  | if (h->desc.irq_off_ms) | 
|  | cancel_delayed_work_sync(&h->isr_work); | 
|  |  | 
|  | h = NULL; | 
|  | } | 
|  | } | 
|  | EXPORT_SYMBOL_GPL(regulator_irq_helper_cancel); |