Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751420Ab3IJKO1 (ORCPT ); Tue, 10 Sep 2013 06:14:27 -0400 Received: from cassiel.sirena.org.uk ([80.68.93.111]:46571 "EHLO cassiel.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750870Ab3IJKOZ (ORCPT ); Tue, 10 Sep 2013 06:14:25 -0400 Date: Tue, 10 Sep 2013 11:13:59 +0100 From: Mark Brown To: Wei Ni Cc: Guenter Roeck , "khali@linux-fr.org" , "swarren@wwwdotorg.org" , "lm-sensors@lm-sensors.org" , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" Message-ID: <20130910101359.GX29403@sirena.org.uk> References: <20130909111242.GW29403@sirena.org.uk> <522DB253.6000707@roeck-us.net> <20130909135022.GZ29403@sirena.org.uk> <20130909155043.GA18975@roeck-us.net> <20130909160237.GR29403@sirena.org.uk> <20130909161735.GC18975@roeck-us.net> <20130909203910.GV29403@sirena.org.uk> <522E9A85.9050803@nvidia.com> <522EA51C.90706@roeck-us.net> <522EB0AF.9030708@nvidia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="FXy67hQeDqxxjNHK" Content-Disposition: inline In-Reply-To: <522EB0AF.9030708@nvidia.com> X-Cookie: Your present plans will be successful. User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 94.175.92.69 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH v3 1/2] hwmon: (lm90) Add power control X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:57:07 +0000) X-SA-Exim-Scanned: Yes (on cassiel.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1940 Lines: 46 --FXy67hQeDqxxjNHK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Sep 10, 2013 at 01:39:59PM +0800, Wei Ni wrote: > I think the device need time to wait stable after power on, but it's > difficult to get an exact delay value, and this delay may also relate > with platform design, so how about to add a optional property in the DT > node, such as "power-on-delay-ms" ? This is something you should *really* be able to get from the datasheet for the part - this sort of stuff has to be documented for hardware to be used robustly. It seems entirely possible that you are working around an issue with the regulator driver you are using not correctly providing its ramp time here. --FXy67hQeDqxxjNHK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.21 (GNU/Linux) iQIcBAEBAgAGBQJSLvDkAAoJELSic+t+oim9MSUP/2DkBcUsNRe50iXk7odxm3Cx Gy5Hmcjm7Krm1uoQhwuaYEUegbqb0KFNGbIHdy9xKtg5QYRn4kWLGwabrFU/JMe1 lRYDcV69Tj4ys7HyHQG6ek4aypoAJ/IR8fAPeUGvtOiUIL0/6hcurswwO4YUfPWP VHhhiDAl7lt5eDjLaEJ+ZxjCpZhc5QgvyHqM/maDh8IaeZjPJT8ftnuJP1kCstIV Rxb5/hdfrdkKgkKRKEqxeWYNsVW+wU8PvJsnZgFdp27Dnh9pv17EqNEUTSFN3SsO LyjDyUw2YpcWjjL2kjlGNKaUz/5Zg8lQXDLmOeE1oxQpUTOTuLstnSpiZ5nMJUBg gTq05caZ2zRBRZRKZ9eQ7cZJ9/uvs4tsHV+SJqJeCSEuluzw9IXmlT4USBOaONFc A7OvGJi6UtefSoGSWpE/jW7zkdmEh3Ir+eGUHchmeJ8PKgURJbf00GokAd4Vol9J tTjOeqrMBd8VayCD5fagOWPWXWUAjArP4+jG0oOPqJ1OfBG143d5+VWfZ2DFjm2P DvgCXfih8FCwgRKCorbWdXf62V9CRv+TebThQp9HNOqF2iY2xM8a1vAHjJWO9xUv iabOQGodVDZYeve8/gOnL0tDgR7jCKmJdb2X3IC8wKU2KuIRPvVV4YqMgU10i8/0 SGtaN6HNhDpTwHzRQNov =1txa -----END PGP SIGNATURE----- --FXy67hQeDqxxjNHK-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/