linux-kernel - Re: [PATCH v4 2/2] mfd: cros_ec: Add cros-usbpd-notify subdevice

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Date:   Mon, 23 Dec 2019 08:25:27 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Prashant Malani <pmalani@...omium.org>, groeck@...omium.org,
        bleung@...omium.org, lee.jones@...aro.org
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/2] mfd: cros_ec: Add cros-usbpd-notify subdevice

Hi Prashant,

On 20/12/19 20:38, Prashant Malani wrote:
> Add the cros-usbpd-notify driver as a subdevice on non-ACPI platforms
> that support the EC_FEATURE_USB_PD EC feature flag.
> 
> This driver allows other cros-ec devices to receive PD event
> notifications from the Chrome OS Embedded Controller (EC) via a
> notification chain.
> 
> Signed-off-by: Prashant Malani <pmalani@...omium.org>
> ---
> 
> Changes in v4:
> - Removed #ifndef usage; instead, moved cros-usbpd-notify to a separate
>   mfd_cell and used an IS_ENABLED() check.
> - Changed commit title and description slightly to reflect change in
>   code.
> 
>  drivers/mfd/cros_ec_dev.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index c4b977a5dd966..da198abe2b0a6 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -5,6 +5,7 @@
>   * Copyright (C) 2014 Google, Inc.
>   */
>  
> +#include <linux/kconfig.h>
>  #include <linux/mfd/core.h>
>  #include <linux/mfd/cros_ec.h>
>  #include <linux/module.h>
> @@ -87,6 +88,10 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
>  	{ .name = "cros-usbpd-logger", },
>  };
>  
> +static const struct mfd_cell cros_usbpd_notify_cells[] = {
> +	{ .name = "cros-usbpd-notify", },
> +};
> +
>  static const struct cros_feature_to_cells cros_subdevices[] = {
>  	{
>  		.id		= EC_FEATURE_CEC,
> @@ -202,6 +207,22 @@ static int ec_device_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> +	/*
> +	 * The PD notifier driver cell is separate since it only needs to be
> +	 * explicitly added on non-ACPI platforms.


Sorry to not catch this before, but a worry arose. Is non-ACPI platforms or
non-X86 platforms or on OF platforms?

ARM64 for example has the CONFIG_ACPI symbol set to yes, with the below
condition condition will not work on Kevin for example and IIUC this is not what
we want, I think we want IS_ENABLED(CONFIG_OF)?

Thanks,
 Enric

> +	 */
> +	if (!IS_ENABLED(CONFIG_ACPI)) {
> +		if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
> +			retval = mfd_add_hotplug_devices(ec->dev,
> +					cros_usbpd_notify_cells,
> +					ARRAY_SIZE(cros_usbpd_notify_cells));
> +			if (retval)
> +				dev_err(ec->dev,
> +					"failed to add PD notify devices: %d\n",
> +					retval);
> +		}
> +	}
> +
>  	/*
>  	 * The following subdevices cannot be detected by sending the
>  	 * EC_FEATURE_GET_CMD to the Embedded Controller device.
>