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From:   Enric Balletbo Serra <eballetbo@gmail.com>
Date:   Thu, 31 May 2018 11:05:09 +0200
Message-ID: <CAFqH_53iMhvq+6NXoXu50sD=PuXBf-2_D3K1Mf+iggLeGSu_mg@mail.gmail.com>
Subject: Re: [PATCH 11/11] misc/throttler: Add Chrome OS EC throttler
To:     Matthias Kaehlcke <mka@chromium.org>
Cc:     MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Linux PM list <linux-pm@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Brian Norris <briannorris@chromium.org>,
        Douglas Anderson <dianders@chromium.org>
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Hi Matthias,

The patch looks good to me, just three minor comments to be more
coherent with other cros-ec drivers.

2018-05-25 22:30 GMT+02:00 Matthias Kaehlcke <mka@chromium.org>:
> 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@chromium.org>
> ---
>  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"

s/Chrome OS/ChromeOS/ This is how other cros-ec drivers refer to the
embedded controller, so will be good if you could maintain this
denomination.

> +       default n
> +       depends on MFD_CROS_EC
> +       ---help---
> +         This driver adds support to throttle the system in reaction to
> +         Chrome OS EC events.
> +

ditto

> +         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.
> + *
> + */
> +

Replace this for the SPDX header format

// SPDX-License-Identifier: GPL-2.0+
// Driver for throttling triggered by EC events.
//
// Copyright (C) 2018 Google, Inc.
// Author: Matthias Kaehlcke <mka@chromium.org>

> +#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);

nit: Better add a define here instead of split the line like this ?

> +       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 <mka@chromium.org>");
> +MODULE_DESCRIPTION("Chrome OS EC Throttler");

s/Chrome OS/ChromeOS/

> --
> 2.17.0.921.gf22659ad46-goog
>

Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Thanks,
  Enric