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Date: Fri, 8 Jun 2018 16:09:18 +0200
From: Enric Balletbo i Serra <enric.balletbo@...labora.com>
To: Matthias Kaehlcke <mka@...omium.org>,
MyungJoo Ham <myungjoo.ham@...sung.com>
Cc: Kyungmin Park <kyungmin.park@...sung.com>,
Chanwoo Choi <cw00.choi@...sung.com>,
Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>, linux-pm@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Brian Norris <briannorris@...omium.org>,
Douglas Anderson <dianders@...omium.org>
Subject: Re: [PATCH v2 11/11] misc: throttler: Add Chrome OS EC throttler
Hi Matthias,
On 07/06/18 20:12, Matthias Kaehlcke wrote:
> 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 <mka@...omium.org>
> Reviewed-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> ---
> Changes in v2:
> - added SPDX line instead of license boiler-plate
> - use macro to avoid splitting line
> - changed variable name for throttler from 'cte' to 'ce_thr'
> - formatting fixes
> - Kconfig: removed odd dashes around 'help'
> - added 'Reviewed-by' tag
>
> Note: I finally decided to keep 'Chrome OS' instead of changing it
> to 'ChromeOS'. Both are currently used in the kernel, the latter is
> currently more prevalent, however the official name is 'Chrome OS',
> so there is no good reason to keep introducing the 'alternative' name.
>
I am pretty sure that somebody from Google told me the contrary, so
¯\_(ツ)_/¯
Anyway, you will probably know better than me :)
> drivers/misc/throttler/Kconfig | 14 +++
> drivers/misc/throttler/Makefile | 1 +
> drivers/misc/throttler/cros_ec_throttler.c | 116 +++++++++++++++++++++
> 3 files changed, 131 insertions(+)
> create mode 100644 drivers/misc/throttler/cros_ec_throttler.c
>
> diff --git a/drivers/misc/throttler/Kconfig b/drivers/misc/throttler/Kconfig
> index e561f1df5085..da6fb70b96d9 100644
> --- a/drivers/misc/throttler/Kconfig
> +++ b/drivers/misc/throttler/Kconfig
> @@ -12,3 +12,17 @@ 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"
> + 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..432135c55600
> --- /dev/null
> +++ b/drivers/misc/throttler/cros_ec_throttler.c
> @@ -0,0 +1,116 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for throttling triggered by events from the Chrome OS Embedded
> + * Controller.
> + *
> + * Copyright (C) 2018 Google, Inc.
> + */
> +
> +#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>
> +
> +#define nb_to_ce_thr(nb) container_of(nb, struct cros_ec_throttler, nb)
> +
> +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 *ce_thr = nb_to_ce_thr(nb);
> + u32 host_event;
> +
> + host_event = cros_ec_get_host_event(ce_thr->ec);
> + if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_THROTTLE_START)) {
> + throttler_set_level(ce_thr->throttler, 1);
> +
> + return NOTIFY_OK;
> + } else if (host_event &
> + EC_HOST_EVENT_MASK(EC_HOST_EVENT_THROTTLE_STOP)) {
> + throttler_set_level(ce_thr->throttler, 0);
> +
> + return NOTIFY_OK;
> + }
> +
> + return NOTIFY_DONE;
> +}
> +
> +static int cros_ec_throttler_probe(struct platform_device *pdev)
> +{
> + struct cros_ec_throttler *ce_thr;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = pdev->dev.of_node;
> + int ret;
> +
> + if (!np) {
> + /* should never happen */
> + return -EINVAL;
> + }
> +
> + ce_thr = devm_kzalloc(dev, sizeof(*ce_thr), GFP_KERNEL);
> + if (!ce_thr)
> + return -ENOMEM;
> +
> + ce_thr->ec = dev_get_drvdata(pdev->dev.parent);
> +
> + ce_thr->throttler = throttler_setup(dev);
> + if (IS_ERR(ce_thr->throttler))
> + return PTR_ERR(ce_thr->throttler);
> +
> + dev_set_drvdata(dev, ce_thr);
> +
> + ce_thr->nb.notifier_call = cros_ec_throttler_event;
> + ret = blocking_notifier_chain_register(&ce_thr->ec->event_notifier,
> + &ce_thr->nb);
> + if (ret < 0) {
> + dev_err(dev, "failed to register notifier\n");
> + throttler_teardown(ce_thr->throttler);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int cros_ec_throttler_remove(struct platform_device *pdev)
> +{
> + struct cros_ec_throttler *ce_thr = platform_get_drvdata(pdev);
> +
> + blocking_notifier_chain_unregister(&ce_thr->ec->event_notifier,
> + &ce_thr->nb);
> +
> + throttler_teardown(ce_thr->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");
Something that I learnt recently. To match the SPDX-license tag you should set
this to "GPL v2" [1]
* "GPL" [GNU Public License v2 or later]
* "GPL v2" [GNU Public License v2]
[1] https://elixir.bootlin.com/linux/v4.17/source/include/linux/module.h#L172
> +MODULE_AUTHOR("Matthias Kaehlcke <mka@...omium.org>");
> +MODULE_DESCRIPTION("Chrome OS EC Throttler");
>
Best regards,
Enric
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