Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 26 Jan 2022 23:04:11 +0000
From:   Alyssa Ross <hi@alyssa.is>
To:     Prashant Malani <pmalani@chromium.org>
Cc:     linux-kernel@vger.kernel.org, Tzung-Bi Shih <tzungbi@google.com>,
        Benson Leung <bleung@chromium.org>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Guenter Roeck <groeck@chromium.org>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>
Subject: Re: [PATCH v2] platform/chrome: cros_ec_typec: Check for EC device
Message-ID: <20220126230411.nn2illij4wbpdm4q@eve>
References: <20220126190219.3095419-1-pmalani@chromium.org>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="ydvev7hvnx7cp4p2"
Content-Disposition: inline
In-Reply-To: <20220126190219.3095419-1-pmalani@chromium.org>
Precedence: bulk


--ydvev7hvnx7cp4p2
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Wed, Jan 26, 2022 at 07:02:20PM +0000, Prashant Malani wrote:
> The Type C ACPI device on older Chromebooks is not generated correctly
> (since their EC firmware doesn't support the new commands required). In
> such cases, the crafted ACPI device doesn't have an EC parent, and it is
> therefore not useful (it shouldn't be generated in the first place since
> the EC firmware doesn't support any of the Type C commands).
>
> To handle devices which use these older firmware revisions, check for
> the parent EC device handle, and fail the probe if it's not found.
>
> Fixes: fdc6b21e2444 ("platform/chrome: Add Type C connector class driver")
> Reported-by: Alyssa Ross <hi@alyssa.is>
> Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
> Signed-off-by: Prashant Malani <pmalani@chromium.org>
> ---
> Hi Alyssa, could you kindly test this with your existing setup? Thanks!

Hi Prashant, I'm happy to test, but I'm on vacation until the end of the
week so probably won't get a chance before Monday.

I'm guessing I should be testing with latest upstream coreboot (now that
your fix there has been applied)?

> Changes in v2:
> - Added newlines as suggested by reviewers.
> - Added Reviewed-by tag from Tzung-Bi.
>
>  drivers/platform/chrome/cros_ec_typec.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 5de0bfb0bc4d..952c1756f59e 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -1075,7 +1075,13 @@ static int cros_typec_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>
>  	typec->dev = dev;
> +
>  	typec->ec = dev_get_drvdata(pdev->dev.parent);
> +	if (!typec->ec) {
> +		dev_err(dev, "couldn't find parent EC device\n");
> +		return -ENODEV;
> +	}
> +
>  	platform_set_drvdata(pdev, typec);
>
>  	ret = cros_typec_get_cmd_version(typec);
> --
> 2.35.0.rc0.227.g00780c9af4-goog
>

--ydvev7hvnx7cp4p2
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=cqF1
-----END PGP SIGNATURE-----

--ydvev7hvnx7cp4p2--