The driver subscribes to throttling events from the Chrome OS embedded controller and enables/disables system throttling based on these events.
Signed-off-by: Matthias Kaehlcke <[email protected]> --- drivers/misc/throttler/Kconfig | 15 +++ drivers/misc/throttler/Makefile | 1 + drivers/misc/throttler/cros_ec_throttler.c | 122 +++++++++++++++++++++ 3 files changed, 138 insertions(+) create mode 100644 drivers/misc/throttler/cros_ec_throttler.c diff --git a/drivers/misc/throttler/Kconfig b/drivers/misc/throttler/Kconfig index ef8388f6bc0a..652b6817b75c 100644 --- a/drivers/misc/throttler/Kconfig +++ b/drivers/misc/throttler/Kconfig @@ -11,3 +11,18 @@ menuconfig THROTTLER Note that you also need a event monitor module usually called *_throttler. +if THROTTLER + +config CROS_EC_THROTTLER + tristate "Throttler event monitor for the Chrome OS Embedded Controller" + default n + depends on MFD_CROS_EC + ---help--- + This driver adds support to throttle the system in reaction to + Chrome OS EC events. + + To compile this driver as a module, choose M here: the + module will be called cros_ec_throttler. + +endif # THROTTLER + diff --git a/drivers/misc/throttler/Makefile b/drivers/misc/throttler/Makefile index c8d920cee315..d9b2a77dabc9 100644 --- a/drivers/misc/throttler/Makefile +++ b/drivers/misc/throttler/Makefile @@ -1 +1,2 @@ obj-$(CONFIG_THROTTLER) += core.o +obj-$(CONFIG_CROS_EC_THROTTLER) += cros_ec_throttler.o diff --git a/drivers/misc/throttler/cros_ec_throttler.c b/drivers/misc/throttler/cros_ec_throttler.c new file mode 100644 index 000000000000..ea6bc002d49c --- /dev/null +++ b/drivers/misc/throttler/cros_ec_throttler.c @@ -0,0 +1,122 @@ +/* + * Driver for throttling triggered by EC events. + * + * Copyright (C) 2018 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/kernel.h> +#include <linux/mfd/cros_ec.h> +#include <linux/module.h> +#include <linux/notifier.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/throttler.h> + +struct cros_ec_throttler { + struct cros_ec_device *ec; + struct throttler *throttler; + struct notifier_block nb; +}; + +static int cros_ec_throttler_event(struct notifier_block *nb, + unsigned long queued_during_suspend, void *_notify) +{ + struct cros_ec_throttler *cte = + container_of(nb, struct cros_ec_throttler, nb); + u32 host_event; + + host_event = cros_ec_get_host_event(cte->ec); + if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_THROTTLE_START)) { + throttler_set_level(cte->throttler, 1); + + return NOTIFY_OK; + } else if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_THROTTLE_STOP)) { + throttler_set_level(cte->throttler, 0); + + return NOTIFY_OK; + } + + return NOTIFY_DONE; +} + +static int cros_ec_throttler_probe(struct platform_device *pdev) +{ + struct cros_ec_throttler *cte; + struct device *dev = &pdev->dev; + struct device_node *np = pdev->dev.of_node; + int ret; + + if (!np) { + /* should never happen */ + return -EINVAL; + } + + cte = devm_kzalloc(dev, sizeof(*cte), GFP_KERNEL); + if (!cte) + return -ENOMEM; + + cte->ec = dev_get_drvdata(pdev->dev.parent); + + cte->throttler = throttler_setup(dev); + if (IS_ERR(cte->throttler)) + return PTR_ERR(cte->throttler); + + dev_set_drvdata(dev, cte); + + cte->nb.notifier_call = cros_ec_throttler_event; + ret = blocking_notifier_chain_register(&cte->ec->event_notifier, + &cte->nb); + if (ret < 0) { + dev_err(dev, "failed to register notifier\n"); + throttler_teardown(cte->throttler); + return ret; + } + + return 0; +} + +static int cros_ec_throttler_remove(struct platform_device *pdev) +{ + struct cros_ec_throttler *cte = platform_get_drvdata(pdev); + + blocking_notifier_chain_unregister(&cte->ec->event_notifier, + &cte->nb); + + throttler_teardown(cte->throttler); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id cros_ec_throttler_of_match[] = { + { .compatible = "google,cros-ec-throttler" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, cros_ec_throttler_of_match); +#endif /* CONFIG_OF */ + +static struct platform_driver cros_ec_throttler_driver = { + .driver = { + .name = "cros-ec-throttler", + .of_match_table = of_match_ptr(cros_ec_throttler_of_match), + }, + .probe = cros_ec_throttler_probe, + .remove = cros_ec_throttler_remove, +}; + +module_platform_driver(cros_ec_throttler_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Matthias Kaehlcke <[email protected]>"); +MODULE_DESCRIPTION("Chrome OS EC Throttler"); -- 2.17.0.921.gf22659ad46-goog
