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![Matti Vaittinen](/assets/img/avatar_default.png)
Provide a generic map_event helper for regulators which have a notification IRQ with single, well defined purpose. Eg, IRQ always indicates exactly one event for exactly one regulator device. For such IRQs the mapping is trivial. Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> Link: https://lore.kernel.org/r/603b7ed1938013a00371c1e7ccc63dfb16982b87.1637736436.git.matti.vaittinen@fi.rohmeurope.com Signed-off-by: Mark Brown <broonie@kernel.org>
436 lines
11 KiB
C
436 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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// Copyright (C) 2021 ROHM Semiconductors
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// regulator IRQ based event notification helpers
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//
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// Logic has been partially adapted from qcom-labibb driver.
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//
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// Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/reboot.h>
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#include <linux/regmap.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/regulator/driver.h>
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#include "internal.h"
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#define REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS 10000
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struct regulator_irq {
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struct regulator_irq_data rdata;
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struct regulator_irq_desc desc;
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int irq;
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int retry_cnt;
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struct delayed_work isr_work;
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};
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/*
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* Should only be called from threaded handler to prevent potential deadlock
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*/
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static void rdev_flag_err(struct regulator_dev *rdev, int err)
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{
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spin_lock(&rdev->err_lock);
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rdev->cached_err |= err;
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spin_unlock(&rdev->err_lock);
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}
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static void rdev_clear_err(struct regulator_dev *rdev, int err)
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{
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spin_lock(&rdev->err_lock);
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rdev->cached_err &= ~err;
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spin_unlock(&rdev->err_lock);
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}
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static void regulator_notifier_isr_work(struct work_struct *work)
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{
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struct regulator_irq *h;
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struct regulator_irq_desc *d;
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struct regulator_irq_data *rid;
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int ret = 0;
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int tmo, i;
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int num_rdevs;
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h = container_of(work, struct regulator_irq,
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isr_work.work);
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d = &h->desc;
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rid = &h->rdata;
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num_rdevs = rid->num_states;
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reread:
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if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
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if (!d->die)
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return hw_protection_shutdown("Regulator HW failure? - no IC recovery",
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REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
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ret = d->die(rid);
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/*
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* If the 'last resort' IC recovery failed we will have
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* nothing else left to do...
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*/
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if (ret)
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return hw_protection_shutdown("Regulator HW failure. IC recovery failed",
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REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
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/*
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* If h->die() was implemented we assume recovery has been
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* attempted (probably regulator was shut down) and we
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* just enable IRQ and bail-out.
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*/
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goto enable_out;
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}
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if (d->renable) {
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ret = d->renable(rid);
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if (ret == REGULATOR_FAILED_RETRY) {
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/* Driver could not get current status */
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h->retry_cnt++;
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if (!d->reread_ms)
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goto reread;
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tmo = d->reread_ms;
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goto reschedule;
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}
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if (ret) {
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/*
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* IC status reading succeeded. update error info
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* just in case the renable changed it.
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*/
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for (i = 0; i < num_rdevs; i++) {
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struct regulator_err_state *stat;
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struct regulator_dev *rdev;
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stat = &rid->states[i];
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rdev = stat->rdev;
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rdev_clear_err(rdev, (~stat->errors) &
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stat->possible_errs);
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}
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h->retry_cnt++;
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/*
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* The IC indicated problem is still ON - no point in
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* re-enabling the IRQ. Retry later.
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*/
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tmo = d->irq_off_ms;
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goto reschedule;
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}
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}
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/*
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* Either IC reported problem cleared or no status checker was provided.
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* If problems are gone - good. If not - then the IRQ will fire again
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* and we'll have a new nice loop. In any case we should clear error
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* flags here and re-enable IRQs.
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*/
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for (i = 0; i < num_rdevs; i++) {
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struct regulator_err_state *stat;
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struct regulator_dev *rdev;
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stat = &rid->states[i];
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rdev = stat->rdev;
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rdev_clear_err(rdev, stat->possible_errs);
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}
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/*
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* Things have been seemingly successful => zero retry-counter.
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*/
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h->retry_cnt = 0;
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enable_out:
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enable_irq(h->irq);
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return;
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reschedule:
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if (!d->high_prio)
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mod_delayed_work(system_wq, &h->isr_work,
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msecs_to_jiffies(tmo));
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else
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mod_delayed_work(system_highpri_wq, &h->isr_work,
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msecs_to_jiffies(tmo));
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}
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static irqreturn_t regulator_notifier_isr(int irq, void *data)
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{
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struct regulator_irq *h = data;
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struct regulator_irq_desc *d;
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struct regulator_irq_data *rid;
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unsigned long rdev_map = 0;
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int num_rdevs;
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int ret, i;
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d = &h->desc;
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rid = &h->rdata;
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num_rdevs = rid->num_states;
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if (d->fatal_cnt)
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h->retry_cnt++;
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/*
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* we spare a few cycles by not clearing statuses prior to this call.
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* The IC driver must initialize the status buffers for rdevs
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* which it indicates having active events via rdev_map.
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*
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* Maybe we should just to be on a safer side(?)
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*/
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ret = d->map_event(irq, rid, &rdev_map);
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/*
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* If status reading fails (which is unlikely) we don't ack/disable
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* IRQ but just increase fail count and retry when IRQ fires again.
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* If retry_count exceeds the given safety limit we call IC specific die
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* handler which can try disabling regulator(s).
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*
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* If no die handler is given we will just power-off as a last resort.
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*
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* We could try disabling all associated rdevs - but we might shoot
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* ourselves in the head and leave the problematic regulator enabled. So
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* if IC has no die-handler populated we just assume the regulator
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* can't be disabled.
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*/
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if (unlikely(ret == REGULATOR_FAILED_RETRY))
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goto fail_out;
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h->retry_cnt = 0;
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/*
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* Let's not disable IRQ if there were no status bits for us. We'd
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* better leave spurious IRQ handling to genirq
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*/
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if (ret || !rdev_map)
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return IRQ_NONE;
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/*
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* Some events are bogus if the regulator is disabled. Skip such events
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* if all relevant regulators are disabled
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*/
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if (d->skip_off) {
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for_each_set_bit(i, &rdev_map, num_rdevs) {
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struct regulator_dev *rdev;
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const struct regulator_ops *ops;
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rdev = rid->states[i].rdev;
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ops = rdev->desc->ops;
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/*
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* If any of the flagged regulators is enabled we do
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* handle this
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*/
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if (ops->is_enabled(rdev))
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break;
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}
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if (i == num_rdevs)
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return IRQ_NONE;
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}
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/* Disable IRQ if HW keeps line asserted */
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if (d->irq_off_ms)
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disable_irq_nosync(irq);
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/*
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* IRQ seems to be for us. Let's fire correct notifiers / store error
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* flags
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*/
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for_each_set_bit(i, &rdev_map, num_rdevs) {
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struct regulator_err_state *stat;
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struct regulator_dev *rdev;
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stat = &rid->states[i];
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rdev = stat->rdev;
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rdev_dbg(rdev, "Sending regulator notification EVT 0x%lx\n",
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stat->notifs);
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regulator_notifier_call_chain(rdev, stat->notifs, NULL);
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rdev_flag_err(rdev, stat->errors);
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}
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if (d->irq_off_ms) {
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if (!d->high_prio)
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schedule_delayed_work(&h->isr_work,
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msecs_to_jiffies(d->irq_off_ms));
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else
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mod_delayed_work(system_highpri_wq,
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&h->isr_work,
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msecs_to_jiffies(d->irq_off_ms));
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}
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return IRQ_HANDLED;
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fail_out:
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if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
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/* If we have no recovery, just try shut down straight away */
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if (!d->die) {
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hw_protection_shutdown("Regulator failure. Retry count exceeded",
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REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
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} else {
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ret = d->die(rid);
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/* If die() failed shut down as a last attempt to save the HW */
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if (ret)
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hw_protection_shutdown("Regulator failure. Recovery failed",
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REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
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}
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}
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return IRQ_NONE;
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}
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static int init_rdev_state(struct device *dev, struct regulator_irq *h,
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struct regulator_dev **rdev, int common_err,
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int *rdev_err, int rdev_amount)
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{
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int i;
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h->rdata.states = devm_kzalloc(dev, sizeof(*h->rdata.states) *
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rdev_amount, GFP_KERNEL);
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if (!h->rdata.states)
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return -ENOMEM;
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h->rdata.num_states = rdev_amount;
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h->rdata.data = h->desc.data;
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for (i = 0; i < rdev_amount; i++) {
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h->rdata.states[i].possible_errs = common_err;
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if (rdev_err)
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h->rdata.states[i].possible_errs |= *rdev_err++;
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h->rdata.states[i].rdev = *rdev++;
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}
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return 0;
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}
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static void init_rdev_errors(struct regulator_irq *h)
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{
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int i;
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for (i = 0; i < h->rdata.num_states; i++)
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if (h->rdata.states[i].possible_errs)
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h->rdata.states[i].rdev->use_cached_err = true;
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}
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/**
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* regulator_irq_helper - register IRQ based regulator event/error notifier
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*
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* @dev: device providing the IRQs
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* @d: IRQ helper descriptor.
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* @irq: IRQ used to inform events/errors to be notified.
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* @irq_flags: Extra IRQ flags to be OR'ed with the default
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* IRQF_ONESHOT when requesting the (threaded) irq.
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* @common_errs: Errors which can be flagged by this IRQ for all rdevs.
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* When IRQ is re-enabled these errors will be cleared
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* from all associated regulators. Use this instead of the
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* per_rdev_errs if you use
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* regulator_irq_map_event_simple() for event mapping.
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* @per_rdev_errs: Optional error flag array describing errors specific
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* for only some of the regulators. These errors will be
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* or'ed with common errors. If this is given the array
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* should contain rdev_amount flags. Can be set to NULL
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* if there is no regulator specific error flags for this
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* IRQ.
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* @rdev: Array of pointers to regulators associated with this
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* IRQ.
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* @rdev_amount: Amount of regulators associated with this IRQ.
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*
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* Return: handle to irq_helper or an ERR_PTR() encoded error code.
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*/
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void *regulator_irq_helper(struct device *dev,
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const struct regulator_irq_desc *d, int irq,
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int irq_flags, int common_errs, int *per_rdev_errs,
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struct regulator_dev **rdev, int rdev_amount)
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{
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struct regulator_irq *h;
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int ret;
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if (!rdev_amount || !d || !d->map_event || !d->name)
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return ERR_PTR(-EINVAL);
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h = devm_kzalloc(dev, sizeof(*h), GFP_KERNEL);
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if (!h)
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return ERR_PTR(-ENOMEM);
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h->irq = irq;
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h->desc = *d;
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ret = init_rdev_state(dev, h, rdev, common_errs, per_rdev_errs,
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rdev_amount);
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if (ret)
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return ERR_PTR(ret);
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init_rdev_errors(h);
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if (h->desc.irq_off_ms)
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INIT_DELAYED_WORK(&h->isr_work, regulator_notifier_isr_work);
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ret = request_threaded_irq(h->irq, NULL, regulator_notifier_isr,
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IRQF_ONESHOT | irq_flags, h->desc.name, h);
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if (ret) {
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dev_err(dev, "Failed to request IRQ %d\n", irq);
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return ERR_PTR(ret);
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}
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return h;
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}
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EXPORT_SYMBOL_GPL(regulator_irq_helper);
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/**
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* regulator_irq_helper_cancel - drop IRQ based regulator event/error notifier
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*
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* @handle: Pointer to handle returned by a successful call to
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* regulator_irq_helper(). Will be NULLed upon return.
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*
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* The associated IRQ is released and work is cancelled when the function
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* returns.
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*/
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void regulator_irq_helper_cancel(void **handle)
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{
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if (handle && *handle) {
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struct regulator_irq *h = *handle;
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free_irq(h->irq, h);
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if (h->desc.irq_off_ms)
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cancel_delayed_work_sync(&h->isr_work);
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h = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(regulator_irq_helper_cancel);
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/**
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* regulator_irq_map_event_simple - regulator IRQ notification for trivial IRQs
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*
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* @irq: Number of IRQ that occurred
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* @rid: Information about the event IRQ indicates
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* @dev_mask: mask indicating the regulator originating the IRQ
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*
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* Regulators whose IRQ has single, well defined purpose (always indicate
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* exactly one event, and are relevant to exactly one regulator device) can
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* use this function as their map_event callbac for their regulator IRQ
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* notification helperk. Exactly one rdev and exactly one error (in
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* "common_errs"-field) can be given at IRQ helper registration for
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* regulator_irq_map_event_simple() to be viable.
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*/
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int regulator_irq_map_event_simple(int irq, struct regulator_irq_data *rid,
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unsigned long *dev_mask)
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{
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int err = rid->states[0].possible_errs;
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*dev_mask = 1;
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/*
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* This helper should only be used in a situation where the IRQ
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* can indicate only one type of problem for one specific rdev.
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* Something fishy is going on if we are having multiple rdevs or ERROR
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* flags here.
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*/
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if (WARN_ON(rid->num_states != 1 || hweight32(err) != 1))
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return 0;
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rid->states[0].errors = err;
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rid->states[0].notifs = regulator_err2notif(err);
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return 0;
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}
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EXPORT_SYMBOL_GPL(regulator_irq_map_event_simple);
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