[v4,3/7] regulator: IRQ based event/error notification helpers

Message ID	2b87b4637fde2225006cc122bc855efca0dcd7f1.1617692184.git.matti.vaittinen@fi.rohmeurope.com (mailing list archive)
State	Superseded
Delegated to:	Geert Uytterhoeven
Headers	show Return-Path: <linux-renesas-soc-owner@kernel.org> Date: Tue, 6 Apr 2021 10:13:13 +0300 From: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> To: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>, Matti Vaittinen <mazziesaccount@gmail.com> Cc: Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>, Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>, Andy Gross <agross@kernel.org>, Bjorn Andersson <bjorn.andersson@linaro.org>, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-power@fi.rohmeurope.com, linux-arm-msm@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: [PATCH v4 3/7] regulator: IRQ based event/error notification helpers Message-ID: <2b87b4637fde2225006cc122bc855efca0dcd7f1.1617692184.git.matti.vaittinen@fi.rohmeurope.com> References: <cover.1617690965.git.matti.vaittinen@fi.rohmeurope.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <cover.1617690965.git.matti.vaittinen@fi.rohmeurope.com> Precedence: bulk
Series	Extend regulator notification support \| expand [v4,0/7] Extend regulator notification support [v4,1/7] dt_bindings: Add protection limit properties [v4,2/7] regulator: add warning flags [v4,3/7] regulator: IRQ based event/error notification helpers [v4,4/7] regulator: add property parsing and callbacks to set protection limits [v4,5/7] dt-bindings: regulator: bd9576 add FET ON-resistance for OCW [v4,6/7] regulator: bd9576: Support error reporting [v4,7/7] regulator: bd9576: Fix the driver name in id table

diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile index 44d2f8bf4b74..e25f1c2d6c9b 100644 --- a/drivers/regulator/Makefile +++ b/drivers/regulator/Makefile @@ -4,7 +4,7 @@ # -obj-$(CONFIG_REGULATOR) += core.o dummy.o fixed-helper.o helpers.o devres.o +obj-$(CONFIG_REGULATOR) += core.o dummy.o fixed-helper.o helpers.o devres.o irq_helpers.o obj-$(CONFIG_OF) += of_regulator.o obj-$(CONFIG_REGULATOR_FIXED_VOLTAGE) += fixed.o obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 16114aea099a..fabc83288e1b 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -4388,20 +4388,37 @@ unsigned int regulator_get_mode(struct regulator *regulator) } EXPORT_SYMBOL_GPL(regulator_get_mode); +static int rdev_get_cached_err_flags(struct regulator_dev *rdev) +{ + int ret = 0; + + if (rdev->use_cached_err) { + spin_lock(&rdev->err_lock); + ret = rdev->cached_err; + spin_unlock(&rdev->err_lock); + } + return ret; +} + static int _regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags) { - int ret; + int ret, tmpret; regulator_lock(rdev); + ret = rdev_get_cached_err_flags(rdev); + /* sanity check */ - if (!rdev->desc->ops->get_error_flags) { + if (rdev->desc->ops->get_error_flags) { + tmpret = rdev->desc->ops->get_error_flags(rdev, flags); + if (tmpret > 0) + ret |= tmpret; + } else if (!rdev->use_cached_err) { ret = -EINVAL; goto out; } - ret = rdev->desc->ops->get_error_flags(rdev, flags); out: regulator_unlock(rdev); return ret; @@ -5236,6 +5253,7 @@ regulator_register(const struct regulator_desc *regulator_desc, goto rinse; } device_initialize(&rdev->dev); + spin_lock_init(&rdev->err_lock); /* * Duplicate the config so the driver could override it after diff --git a/drivers/regulator/irq_helpers.c b/drivers/regulator/irq_helpers.c new file mode 100644 index 000000000000..cc0c23c23b5f --- /dev/null +++ b/drivers/regulator/irq_helpers.c @@ -0,0 +1,432 @@ +// 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/kernel.h> +#include <linux/of_irq.h> +#include <linux/regmap.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/regulator/driver.h> + +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 die_loudly(const char *msg) +{ + pr_emerg(msg); + BUG(); +} + +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) + ret = d->die(rid); + else + die_loudly("Regulator HW failure? - no IC recovery\n"); + + /* + * If the 'last resort' IC recovery failed we will have + * nothing else left to do... + */ + if (ret) + die_loudly("Regulator HW failure? - IC recovery failed\n"); + + /* + * 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 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, j; + + d = &h->desc; + rid = &h->rdata; + num_rdevs = rid->num_states; + + if (d->fatal_cnt) + h->retry_cnt++; + + /* + * we spare few cycles by not clearing statuses prior 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 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 + * ourself in the head and leave 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 was 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 regulator is disabled. Skip such events + * if all relevant regulators are disabled + */ + if (d->skip_off) { + int skip = 1; + + 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)) { + skip = 0; + break; + } + } + if (skip) + 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; + int len; + struct regulator_dev *rdev; + + stat = &rid->states[i]; + len = sizeof(stat->notifs); + + rdev = stat->rdev; + for_each_set_bit(j, &stat->notifs, 8 * len) + regulator_notifier_call_chain(rdev, 1 << (j - 1), 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 (d->die) + ret = d->die(rid); + + /* + * If die() failed or was not implemented just BUG() as last + * attemt to save HW. + */ + if (ret) + die_loudly("Regulator HW failure? - retry count exceeded\n"); + } + + 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) + /* Can we trust writing this boolean is atomic? */ + h->rdata.states[i].rdev->use_cached_err = true; + } +} + +/** + * regulator_irq_helper - register IRQ based regulator event/error notifier + * + * @dev: device to which lifetime the helper's lifetime is + * bound. + * @d: IRQ helper descriptor. + * @irq: IRQ used to inform events/errors to be notified. + * @irq_flags: Extra IRQ flags to be OR's 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 erros. 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 regulators associated with this IRQ. + * @rdev_amount: Amount of regulators associated wit this IRQ. + */ +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); + + if (irq <= 0) { + dev_err(dev, "No IRQ\n"); + 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) + 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); + +static void regulator_irq_helper_drop(struct device *dev, void *res) +{ + regulator_irq_helper_cancel(res); +} + +void *devm_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) +{ + void **ptr; + + ptr = devres_alloc(regulator_irq_helper_drop, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + *ptr = regulator_irq_helper(dev, d, irq, irq_flags, common_errs, + per_rdev_errs, rdev, rdev_amount); + + if (IS_ERR(*ptr)) + devres_free(ptr); + else + devres_add(dev, ptr); + + return *ptr; +} +EXPORT_SYMBOL_GPL(devm_regulator_irq_helper); diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h index d7c77ee370f3..03a8eee9fca9 100644 --- a/include/linux/regulator/driver.h +++ b/include/linux/regulator/driver.h @@ -409,6 +409,128 @@ struct regulator_config { struct gpio_desc *ena_gpiod; }; +/** + * struct regulator_err_state - regulator error/notification status + * + * @rdev: Regulator which status the struct indicates. + * @notifs: Events which have occurred on regulator. + * @errors: Errors which are active on regulator. + * @possible_errs: Errors which can be signaled (by given IRQ). + */ +struct regulator_err_state { + struct regulator_dev *rdev; + unsigned long notifs; + unsigned long errors; + int possible_errs; +}; + +/** + * struct regulator_irq_data - regulator error/notification status date + * + * @states: Status structs for each of the associated regulators. + * @num_states: Amount of associated regulators. + * @data: Driver data pointer given at regulator_irq_desc. + * @opaque: Value storage for IC driver. Core does not update this. ICs + * may want to store status register value here at map_event and + * compare contents at renable to see if new problems have been + * added to status. If that is the case it may be desirable to + * return REGULATOR_ERROR_CLEARED and not REGULATOR_ERROR_ON to + * allow IRQ fire again and to generate notifications also for + * the new issues. + * + * This structure is passed to map_event and renable for reporting regulator + * status to core. + */ +struct regulator_irq_data { + struct regulator_err_state *states; + int num_states; + void *data; + long opaque; +}; + +/** + * struct regulator_irq_desc - notification sender for IRQ based events. + * + * @name: The visible name for the IRQ + * @fatal_cnt: If this IRQ is used to signal HW damaging condition it may be + * best to shut-down regulator(s) or reboot the SOC if error + * handling is repeteadly failing. If fatal_cnt is given the IRQ + * handling is aborted if it fails for fatal_cnt times and die() + * callback (if populated) or BUG() is called to try to prevent + * further damage. + * @reread_ms: The time which is waited before attempting to re-read status + * at the worker if IC reading fails. Immediate re-read is done + * if time is not specified. + * @irq_off_ms: The time which IRQ is kept disabled before re-evaluating the + * status for devices which keep IRQ disabled for duration of the + * error. If this is not given the IRQ is left enabled and renable + * is not called. + * @skip_off: If set to true the IRQ handler will attempt to check if any of + * the associated regulators are enabled prior to taking other + * actions. If no regulators are enabled and this is set to true + * a spurious IRQ is assumed and IRQ_NONE is returned. + * @high_prio: Boolean to indicate that high priority WQ should be used. + * @data: Driver private data pointer which will be passed as such to + * the renable, map_event and die callbacks in regulator_irq_data. + * @die: Protection callback. If IC status reading or recovery actions + * fail fatal_cnt times this callback or BUG() is called. This + * callback should implement final protection attempt like + * disabling the regulator. If protection succeeded this may + * return 0. If anything else is returned the core assumes final + * protection failed and calls BUG() as a last resort. + * @map_event: Driver callback to map IRQ status into regulator devices with + * events / errors. NOTE: callback MUST initialize both the + * errors and notifs for all rdevs which it signals having + * active events as core does not clean the map data. + * REGULATOR_FAILED_RETRY can be returned to indicate that the + * status reading from IC failed. If this is repeated for + * fatal_cnt times the core will call die() callback or BUG() + * as a last resort to protect the HW. + * @renable: Optional callback to check status (if HW supports that) before + * re-enabling IRQ. If implemented this should clear the error + * flags so that errors fetched by regulator_get_error_flags() + * are updated. If callback is not impelemted then errors are + * assumed to be cleared and IRQ is re-enabled. + * REGULATOR_FAILED_RETRY can be returned to + * indicate that the status reading from IC failed. If this is + * repeated for 'fatal_cnt' times the core will call die() + * callback or BUG() as a last resort to protect the HW. + * Returning zero indicates that the problem in HW has been solved + * and IRQ will be re-enabled. Returning REGULATOR_ERROR_ON + * indicates the error condition is still active and keeps IRQ + * disabled. Please note that returning REGULATOR_ERROR_ON does + * not retrigger evaluating what events are active or resending + * notifications. If this is needed you probably want to return + * zero and allow IRQ to retrigger causing events to be + * re-evaluated and re-sent. + * + * This structure is used for registering regulator IRQ notification helper. + */ +struct regulator_irq_desc { + const char *name; + int irq_flags; + int fatal_cnt; + int reread_ms; + int irq_off_ms; + bool skip_off; + bool high_prio; + void *data; + + int (*die)(struct regulator_irq_data *rid); + int (*map_event)(int irq, struct regulator_irq_data *rid, + unsigned long *dev_mask); + int (*renable)(struct regulator_irq_data *rid); +}; + +/* + * Return values for regulator IRQ helpers. + */ +enum { + REGULATOR_ERROR_CLEARED, + REGULATOR_FAILED_RETRY, + REGULATOR_ERROR_ON, +}; + /* * struct coupling_desc * @@ -473,6 +595,9 @@ struct regulator_dev { /* time when this regulator was disabled last time */ unsigned long last_off_jiffy; + int cached_err; + bool use_cached_err; + spinlock_t err_lock; }; struct regulator_dev * @@ -487,6 +612,16 @@ void devm_regulator_unregister(struct device *dev, struct regulator_dev *rdev); int regulator_notifier_call_chain(struct regulator_dev *rdev, unsigned long event, void *data); +void *devm_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); +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); +void regulator_irq_helper_cancel(void **handle); void *rdev_get_drvdata(struct regulator_dev *rdev); struct device *rdev_get_dev(struct regulator_dev *rdev);

[v4,3/7] regulator: IRQ based event/error notification helpers

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