From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH v2 04/13] ARM: tegra: Add MIPI calibration DT entries for Tegra114 Date: Wed, 16 Oct 2013 12:57:44 +0200 Message-ID: <20131016105743.GG21963@ulmo.nvidia.com> References: <1381850883-12722-1-git-send-email-treding@nvidia.com> <1381850883-12722-5-git-send-email-treding@nvidia.com> <525DA888.2060800@wwwdotorg.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="oOB74oR0WcNeq9Zb" Return-path: Content-Disposition: inline In-Reply-To: <525DA888.2060800-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren Cc: linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org --oOB74oR0WcNeq9Zb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 15, 2013 at 02:41:44PM -0600, Stephen Warren wrote: > On 10/15/2013 09:27 AM, Thierry Reding wrote: > > Add a device node for the MIPI calibration block on Tegra114. There is > > no need to disable it by default because it only enables the clock while > > performing calibration and therefore shouldn't be consuming any power > > when unused. >=20 > > diff --git a/arch/arm/boot/dts/tegra114.dtsi b/arch/arm/boot/dts/tegra1= 14.dtsi >=20 > > + mipi: mipi { > > + compatible =3D "nvidia,tegra114-mipi"; > > + reg =3D <0x700e3000 0x100>; > > + clocks =3D <&tegra_car TEGRA114_CLK_MIPI_CAL>; > > + #calibrate-cells =3D <1>; > > + }; >=20 > Do you have a link to the binding documentation for this? I'm still in > the dark re: why there's a need for #calibrate-cells at all. It seems > like this should be some internal implementation detail of the Tegra > DC/..., or implicit based on the compatible value (if cell count > changes, just rev the compatible value; it's not like this is a generic > service for loosely coupled drivers). Here's the commit that adds the device tree binding: https://gitorious.org/thierryreding/linux/commit/43b798a54063156692e0fde2a= 9022c0ae44b862e I was under the impression that we needed the #*-cells properties so that the device tree code could verify that the content is actually correct and so that it knows how to parse the specifier. I mean why else do we have the #gpio-cells property for GPIO controller nodes? Also note that this driver isn't for something internal to the DRM driver. It can (and will) also be used by the V4L2 camera driver that Bryan is working on, because the CSI pads need to be calibrated in the same way. Thierry --oOB74oR0WcNeq9Zb Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJSXnEnAAoJEN0jrNd/PrOh0UUP/iiK+FcoSKDShGwendhb6gUZ IZnMjA/E8jg5H0q/Ab5wVZbCZW+jB979G2b6XyRKOn6rWQRvIGjJwcMZwPBs2K8m JczUsWic0uAfxXZHa0BaJZxeSg/RpvttsMX94CoPoYc4rHZVNlNPwC6cgtw5fmgW HtSZjH3rp+hIP9qWs5N7UEVtPvY5oKOMgEdEc6kM2SJiQsLt7EKBmuw/BlrpwusD XyzzNIsi8om4+6rpnHRAypKU0QTpcrLa88buoKK6qNIWqay0zOhmKi/XZ0/0vFhF MjTzEpx1ITUKgVdW+RWrTKCJOC+WqRY+BF0db2PbhlvOTsCqMw+1/GwzUlZKGR4C Vdua+WVFoW1HF/U9U54drJSvjxmw+aTlqswVELSQX94QWCcPRN0Xliz8Q6RCWHYP tyi6X1ka7Lg6kRo6FO8bAUclHQ3a5XrRUBhyBK20CrkGOmd1YgZuoLAS7Do0D5NM wSJvL3okPcHu60iyH0dtHd+6rvy8hQ6dQSF2uMsNnE1PBMly0pneEPuA+pclQB4f tajQzHD6bMHw408//3rIV80AOkk3vLqjJitw+/7dAGLqbgZkSZ9cZsb9DbK9GrJa +yI+hl2rEbADu8aTgKEwAsXAljkLY76gQCrYIRIysJnHB8nXOW7v9rP1nGOvMnLU UFQBie++dJD/qCNaCXyo =XQYk -----END PGP SIGNATURE----- --oOB74oR0WcNeq9Zb--