diff options
Diffstat (limited to 'drivers/regulator/irq_helpers.c')
| -rw-r--r-- | drivers/regulator/irq_helpers.c | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/drivers/regulator/irq_helpers.c b/drivers/regulator/irq_helpers.c new file mode 100644 index 000000000000..fabe2e53093e --- /dev/null +++ b/drivers/regulator/irq_helpers.c @@ -0,0 +1,397 @@ +// 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); |