linux-stable/drivers/regulator/irq_helpers.c
Matti Vaittinen ad3ead1efe
regulator: Documentation fix for regulator error notification helper
The helper to send IRQ notification for regulator errors had still
old description mentioning calling BUG() as a last resort when
error status reading has kept failing for more times than a given
threshold.

The impementation calling BUG() did never end-up in-tree but was
replaced by hopefully more sophisticated handler trying to power-off
the system.

Fix the documentation to reflect actual behaviour.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20210823075651.GA3717293@localhost.localdomain
Signed-off-by: Mark Brown <broonie@kernel.org>
2021-08-23 11:06:28 +01:00

397 lines
10 KiB
C

// 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 power-off 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);