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References: <20230104060846.112216-1-pmalani@chromium.org>
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From:   Benson Leung <bleung@chromium.org>
Date:   Thu, 5 Jan 2023 10:44:41 -0800
Message-ID: <CANLzEkuV3r6hQeB_e5qHm7eWLF2VftH-U9sbED30wWmu29UEyg@mail.gmail.com>
Subject: Re: [PATCH 1/2] platform/chrome: cros_typec_switch: Use fwnode* prop check
To:     Prashant Malani <pmalani@chromium.org>
Cc:     linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev
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Precedence: bulk

Hi Prashant,

On Tue, Jan 3, 2023 at 10:09 PM Prashant Malani <pmalani@chromium.org> wrote:
>
> Using device_property_present() multiple times on an ACPI device
> leads to kernel panics on Chromebook systems. This happens when there
> is > 1 boolean property in an ACPI device which is created dynamically
> by the BIOS as part of SSDT[1] on Chromebook systems
>
> Since fwnode_* can handle simple device tree properties equally
> well, switch to using the fwnode_property_present() function
> version. This will avoid panics and make the usage consistent
> when we introduce a check for the 2nd property in a subsequent patch.
>
> [1] https://wiki.osdev.org/SSDT
>
> Signed-off-by: Prashant Malani <pmalani@chromium.org>

Reviewed-by: Benson Leung <bleung@chromium.org>

Thanks,
Benson

> ---
>  drivers/platform/chrome/cros_typec_switch.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
> index a26219e97c93..2536bda03bf3 100644
> --- a/drivers/platform/chrome/cros_typec_switch.c
> +++ b/drivers/platform/chrome/cros_typec_switch.c
> @@ -254,7 +254,7 @@ static int cros_typec_register_switches(struct cros_typec_switch_data *sdata)
>
>                 dev_dbg(dev, "Retimer switch registered for index %llu\n", index);
>
> -               if (!device_property_present(fwnode->dev, "mode-switch"))
> +               if (!fwnode_property_present(fwnode, "mode-switch"))
>                         continue;
>
>                 ret = cros_typec_register_mode_switch(port, fwnode);
> --
> 2.39.0.314.g84b9a713c41-goog
>
>


-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@google.com
Chromium OS Project
bleung@chromium.org