linux-kernel - Re: [PATCH v4 3/3] mfd: cros_ec: Don't add cros_ec

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Message-ID: <CANFp7mV0FjZ-4OB8uMeVfyQn_BAMhnhYs-w+ABzupoiiywN1Gg@mail.gmail.com>
Date: Thu, 6 Nov 2025 10:18:22 -0800
From: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To: Jameson Thies <jthies@...gle.com>
Cc: dmitry.baryshkov@....qualcomm.com, akuchynski@...omium.org, 
	krzk+dt@...nel.org, robh@...nel.org, bleung@...omium.org, 
	heikki.krogerus@...ux.intel.com, ukaszb@...omium.org, tzungbi@...nel.org, 
	devicetree@...r.kernel.org, chrome-platform@...ts.linux.dev, 
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/3] mfd: cros_ec: Don't add cros_ec_ucsi if it is
 defined in OF or ACPI

On Mon, Oct 13, 2025 at 1:34 PM Jameson Thies <jthies@...gle.com> wrote:
>
> On devices with a UCSI PPM in the EC, check for cros_ec_ucsi to be
> defined in the OF device tree or an ACPI node. If it is defined by
> either OF or ACPI, it does not need to be added as a subdevice of
> cros_ec_dev mfd. cros_ec_ucsi will load from the OF or ACPI node.
>
> Signed-off-by: Jameson Thies <jthies@...gle.com>
> Reviewed-by: Benson Leung <bleung@...omium.org>
> ---
>  drivers/mfd/cros_ec_dev.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index dc80a272726b..1928c2ea2b8f 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/acpi.h>
>  #include <linux/dmi.h>
>  #include <linux/kconfig.h>
>  #include <linux/mfd/core.h>
> @@ -131,11 +132,6 @@ static const struct cros_feature_to_cells cros_subdevices[] = {
>                 .mfd_cells      = cros_ec_rtc_cells,
>                 .num_cells      = ARRAY_SIZE(cros_ec_rtc_cells),
>         },
> -       {
> -               .id             = EC_FEATURE_UCSI_PPM,
> -               .mfd_cells      = cros_ec_ucsi_cells,
> -               .num_cells      = ARRAY_SIZE(cros_ec_ucsi_cells),
> -       },
>         {
>                 .id             = EC_FEATURE_HANG_DETECT,
>                 .mfd_cells      = cros_ec_wdt_cells,
> @@ -264,6 +260,23 @@ static int ec_device_probe(struct platform_device *pdev)
>                 }
>         }
>
> +       /*
> +        * FW nodes can load cros_ec_ucsi, but early PDC devices did not define
> +        * the required nodes. On PDC systems without FW nodes for cros_ec_ucsi,
> +        * the driver should be added as an mfd subdevice.
> +        */
> +       if (cros_ec_check_features(ec, EC_FEATURE_USB_PD) &&
> +           cros_ec_check_features(ec, EC_FEATURE_UCSI_PPM) &&
> +           !acpi_dev_found("GOOG0021") &&
> +           !of_find_compatible_node(NULL, NULL, "google,cros-ec-ucsi")) {
> +               retval = mfd_add_hotplug_devices(ec->dev,
> +                                                cros_ec_ucsi_cells,
> +                                                ARRAY_SIZE(cros_ec_ucsi_cells));
> +
> +               if (retval)
> +                       dev_warn(ec->dev, "failed to add cros_ec_ucsi: %d\n", retval);
> +       }
> +
>         /*
>          * UCSI provides power supply information so we don't need to separately
>          * load the cros_usbpd_charger driver.
> --
> 2.51.0.858.gf9c4a03a3a-goog
>

Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>