linux-kernel - Re: [PATCH 2/3] power: supply: cros-ec-usbpd-charger: Fix host events

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Date:   Thu, 14 Nov 2019 22:53:51 +0100
From:   Enric Balletbo Serra <eballetbo@...il.com>
To:     Jon Flatley <jflat@...omium.org>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Sebastian Reichel <sre@...nel.org>
Subject: Re: [PATCH 2/3] power: supply: cros-ec-usbpd-charger: Fix host events

Hi Jon,

Some comments below.

Missatge de Jon Flatley <jflat@...omium.org> del dia dc., 13 de nov.
2019 a les 4:19:
>
> There's a bug on ACPI platforms where host events from the ECPD ACPI
> device never make their way to the cros-ec-usbpd-charger driver. This
> makes it so the only time the charger driver updates its state is when
> user space accesses its sysfs attributes.
>
> Now that these events have been unified into a single notifier chain on
> both ACPI and non-ACPI platforms the charger driver can just be updated
> to use this new notifer.
>
> Signed-off-by: Jon Flatley <jflat@...omium.org>
> ---
>  drivers/power/supply/Kconfig              |  2 +-
>  drivers/power/supply/cros_usbpd-charger.c | 45 ++++++++---------------
>  2 files changed, 17 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index c84a7b1caeb6..7664849d7680 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -659,7 +659,7 @@ config CHARGER_RT9455
>
>  config CHARGER_CROS_USBPD
>         tristate "ChromeOS EC based USBPD charger"
> -       depends on CROS_EC
> +       depends on CROS_EC_USBPD_NOTIFY
>         default n
>         help
>           Say Y here to enable ChromeOS EC based USBPD charger
> diff --git a/drivers/power/supply/cros_usbpd-charger.c b/drivers/power/supply/cros_usbpd-charger.c
> index 6cc7c3910e09..58cf51b51179 100644
> --- a/drivers/power/supply/cros_usbpd-charger.c
> +++ b/drivers/power/supply/cros_usbpd-charger.c
> @@ -8,6 +8,7 @@
>  #include <linux/mfd/cros_ec.h>
>  #include <linux/module.h>
>  #include <linux/platform_data/cros_ec_commands.h>
> +#include <linux/platform_data/cros_ec_usbpd_notify.h>
>  #include <linux/platform_data/cros_ec_proto.h>
>  #include <linux/platform_device.h>
>  #include <linux/power_supply.h>
> @@ -524,32 +525,22 @@ static int cros_usbpd_charger_property_is_writeable(struct power_supply *psy,
>  }
>
>  static int cros_usbpd_charger_ec_event(struct notifier_block *nb,
> -                                      unsigned long queued_during_suspend,
> +                                      unsigned long host_event,
>                                        void *_notify)
>  {
> -       struct cros_ec_device *ec_device;
>         struct charger_data *charger;
> -       u32 host_event;
>
>         charger = container_of(nb, struct charger_data, notifier);
> -       ec_device = charger->ec_device;
>
> -       host_event = cros_ec_get_host_event(ec_device);
> -       if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU)) {
> -               cros_usbpd_charger_power_changed(charger->ports[0]->psy);
> -               return NOTIFY_OK;
> -       } else {
> -               return NOTIFY_DONE;
> -       }
> +       cros_usbpd_charger_power_changed(charger->ports[0]->psy);
> +       return NOTIFY_OK;
>  }
>
>  static void cros_usbpd_charger_unregister_notifier(void *data)
>  {
>         struct charger_data *charger = data;
> -       struct cros_ec_device *ec_device = charger->ec_device;
>
> -       blocking_notifier_chain_unregister(&ec_device->event_notifier,
> -                                          &charger->notifier);
> +       cros_ec_usbpd_unregister_notify(&charger->notifier);
>  }
>

Can we get rid of this function and call directly
cros_ec_usbpd_unregister_notify where the function is used?

>  static int cros_usbpd_charger_probe(struct platform_device *pd)
> @@ -683,21 +674,17 @@ static int cros_usbpd_charger_probe(struct platform_device *pd)
>                 goto fail;
>         }
>
> -       if (ec_device->mkbp_event_supported) {
> -               /* Get PD events from the EC */
> -               charger->notifier.notifier_call = cros_usbpd_charger_ec_event;
> -               ret = blocking_notifier_chain_register(
> -                                               &ec_device->event_notifier,
> -                                               &charger->notifier);
> -               if (ret < 0) {
> -                       dev_warn(dev, "failed to register notifier\n");
> -               } else {
> -                       ret = devm_add_action_or_reset(dev,
> -                                       cros_usbpd_charger_unregister_notifier,
> -                                       charger);
> -                       if (ret < 0)
> -                               goto fail;
> -               }
> +       /* Get PD events from the EC */
> +       charger->notifier.notifier_call = cros_usbpd_charger_ec_event;
> +       ret = cros_ec_usbpd_register_notify(&charger->notifier);
> +       if (ret < 0) {
> +               dev_warn(dev, "failed to register notifier\n");

Hmm, now I am wondering if should we only warn and continue or fail.
Makes sense have this without the notifier?

> +       } else {
> +               ret = devm_add_action_or_reset(dev,
> +                               cros_usbpd_charger_unregister_notifier,
> +                               charger);
> +               if (ret < 0)
> +                       goto fail;
>         }
>
>         return 0;
> --
> 2.24.0.432.g9d3f5f5b63-goog
>

Thanks,
 Enric