linux-kernel - Re: [PATCH v5 1/2] platform: chrome: Add cros-usbpd-notify driver

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Message-ID: <CACeCKacSiMQOA63c81deGHOvKZb=MEFQqjK=iQRmmot8GrjS+A@mail.gmail.com>
Date:   Tue, 14 Jan 2020 11:23:53 -0800
From:   Prashant Malani <pmalani@...omium.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Guenter Roeck <groeck@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Lee Jones <lee.jones@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Jon Flatley <jflat@...omium.org>,
        Gwendal Grignou <gwendal@...omium.org>
Subject: Re: [PATCH v5 1/2] platform: chrome: Add cros-usbpd-notify driver

On Tue, Jan 14, 2020 at 9:07 AM Enric Balletbo i Serra
<enric.balletbo@...labora.com> wrote:
>
> Hi Prashant,
>
> On 14/1/20 4:10, Prashant Malani wrote:
> > From: Jon Flatley <jflat@...omium.org>
> > +};
> > +MODULE_DEVICE_TABLE(acpi, cros_usbpd_acpi_device_ids);
> Ops, there is a build error here, please make sure to build the driver before
> sending.
Hmm. That's odd, I did check  using arm64 defconfig. My apologies.
Could you kindly share your build commands so that I can use this
going forward?
>
> s/cros_usbpd_acpi_device_ids/cros_usbpd_notify_acpi_device_ids/
>
> Apart from this I'm getting build errors with my defconfig which has CONFIG_ACPI
> and CONFIG_OF enabled.
>
> Another problem that I have with this driver is that actually there is no user
> for it. I'd really prefer have this included on a series that also introduces
> the user of this notifier. If you are only testing the ACPI case you can focus
> first on this use case and we add later the OF case (maybe is an easy way to
> proceed).
I'm testing with an arm64 device too locally. I will try to
incorporate the new change which updates cros_usbpd-charger to use the
notifier mechanism. I think we can try for the OF case simultaneously
(it is probably just the build errors I need to check for)

Thanks again!
>
> Thanks,
>  Enric
>
> > +
> > +static struct acpi_driver cros_usbpd_notify_acpi_driver = {
> > +     .name = DRV_NAME,
> > +     .class = DRV_NAME,
> > +     .ids = cros_usbpd_notify_acpi_device_ids,
> > +     .ops = {
> > +             .add = cros_usbpd_notify_add_acpi,
> > +             .notify = cros_usbpd_notify_acpi,
> > +     },
> > +};
> > +module_acpi_driver(cros_usbpd_notify_acpi_driver);
> > +
> > +#endif /* CONFIG_ACPI */
> > +
> > +#ifdef CONFIG_OF
> > +
> > +static int cros_usbpd_notify_plat(struct notifier_block *nb,
> > +             unsigned long queued_during_suspend, void *data)
> > +{
> > +     struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
> > +     u32 host_event = cros_ec_get_host_event(ec_dev);
> > +
> > +     if (!host_event)
> > +             return NOTIFY_BAD;
> > +
> > +     if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU)) {
> > +             blocking_notifier_call_chain(&cros_usbpd_notifier_list,
> > +                             host_event, NULL);
> > +             return NOTIFY_OK;
> > +     }
> > +     return NOTIFY_DONE;
> > +}
> > +
> > +static int cros_usbpd_notify_probe_plat(struct platform_device *pdev)
> > +{
> > +     struct device *dev = &pdev->dev;
> > +     struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
> > +     struct notifier_block *nb;
> > +     int ret;
> > +
> > +     nb = devm_kzalloc(dev, sizeof(*nb), GFP_KERNEL);
> > +     if (!nb)
> > +             return -ENOMEM;
> > +
> > +     nb->notifier_call = cros_usbpd_notify_plat;
> > +     dev_set_drvdata(dev, nb);
> > +
> > +     ret = blocking_notifier_chain_register(&ecdev->ec_dev->event_notifier,
> > +                                             nb);
> > +     if (ret < 0) {
> > +             dev_err(dev, "Failed to register notifier\n");
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int cros_usbpd_notify_remove_plat(struct platform_device *pdev)
> > +{
> > +     struct device *dev = &pdev->dev;
> > +     struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
> > +     struct notifier_block *nb =
> > +             (struct notifier_block *)dev_get_drvdata(dev);
> > +
> > +     blocking_notifier_chain_unregister(&ecdev->ec_dev->event_notifier,
> > +                     nb);
> > +
> > +     return 0;
> > +}
> > +
> > +static struct platform_driver cros_usbpd_notify_plat_driver = {
> > +     .driver = {
> > +             .name = DRV_NAME,
> > +     },
> > +     .probe = cros_usbpd_notify_probe_plat,
> > +     .remove = cros_usbpd_notify_remove_plat,
> > +};
> > +module_platform_driver(cros_usbpd_notify_plat_driver);
> > +
> > +#endif /* CONFIG_OF */
> > +
> > +MODULE_LICENSE("GPL");
> > +MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
> > +MODULE_AUTHOR("Jon Flatley <jflat@...omium.org>");
> > +MODULE_ALIAS("platform:" DRV_NAME);
> > diff --git a/include/linux/platform_data/cros_usbpd_notify.h b/include/linux/platform_data/cros_usbpd_notify.h
> > new file mode 100644
> > index 0000000000000..4f2791722b6d3
> > --- /dev/null
> > +++ b/include/linux/platform_data/cros_usbpd_notify.h
> > @@ -0,0 +1,17 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * ChromeOS EC Power Delivery Notifier Driver
> > + *
> > + * Copyright 2020 Google LLC
> > + */
> > +
> > +#ifndef __LINUX_PLATFORM_DATA_CROS_USBPD_NOTIFY_H
> > +#define __LINUX_PLATFORM_DATA_CROS_USBPD_NOTIFY_H
> > +
> > +#include <linux/notifier.h>
> > +
> > +int cros_usbpd_register_notify(struct notifier_block *nb);
> > +
> > +void cros_usbpd_unregister_notify(struct notifier_block *nb);
> > +
> > +#endif  /* __LINUX_PLATFORM_DATA_CROS_USBPD_NOTIFY_H */
> >