From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Date: Wed, 27 Aug 2014 15:42:21 +0000 Subject: Re: [linux-sunxi] Re: [PATCH 4/4] simplefb: add clock handling code Message-Id: <20140827154221.GX15297@lukather> MIME-Version: 1 Content-Type: multipart/mixed; boundary="A7dSUaxngFh2KEF6" List-Id: References: <20140825145854.GA15297@lukather> <20140825150501.GE14763@ulmo.nvidia.com> <20140825152232.GE15297@lukather> <20140826080432.GD17263@ulmo> <20140826135341.GM15297@lukather> <20140826143550.GB3027@ulmo> <20140826210248.GO15297@lukather> <20140827065440.GG15640@ulmo> <20140827084526.GR15297@lukather> <20140827095241.GC23186@ulmo> In-Reply-To: <20140827095241.GC23186@ulmo> To: linux-arm-kernel@lists.infradead.org --A7dSUaxngFh2KEF6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 27, 2014 at 11:52:48AM +0200, Thierry Reding wrote: > On Wed, Aug 27, 2014 at 10:45:26AM +0200, Maxime Ripard wrote: > > On Wed, Aug 27, 2014 at 08:54:41AM +0200, Thierry Reding wrote: > > > On Tue, Aug 26, 2014 at 11:02:48PM +0200, Maxime Ripard wrote: > > > > On Tue, Aug 26, 2014 at 04:35:51PM +0200, Thierry Reding wrote: > [...] > > > > > > Mike Turquette repeatedly said that he was against such a DT pr= operty: > > > > > > https://lkml.org/lkml/2014/5/12/693 > > > > >=20 > > > > > Mike says in that email that he's opposing the addition of a prop= erty > > > > > for clocks that is the equivalent of regulator-always-on. That's = not > > > > > what this is about. If at all it'd be a property to mark a clock = that > > > > > should not be disabled by default because it's essential. > > > >=20 > > > > It's just semantic. How is "a clock that should not be disabled by > > > > default because it's essential" not a clock that stays always on? > > >=20 > > > Because a clock that should not be disabled by default can be turned = off > > > when appropriate. A clock that is always on can't be turned off. > >=20 > > If a clock is essential, then it should never be disabled. Or we don't > > share the same meaning of essential. >=20 > Essential for the particular use-case. So, how would the clock driver would know about which use case we're in? How would it know about which display engine is currently running? How would it know about which video output is being set? Currently, we have two separate display engines, which can each output either to 4 different outputs (HDMI, RGB/LVDS, 2 DSI). Each and every one of these combinations would require different clocks. What clocks will we put in the driver? All of them? Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --A7dSUaxngFh2KEF6 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJT/fxdAAoJEBx+YmzsjxAgaHQQALDRGwdTzEHkd1r1RvFu71Zk GYm+lHXW2pLc+8djR/onJEBmINLoaIuqwnxPQZ2f91BeA07zeqQRCz3gJup+uCNB WBNXxYhEc54qEVuJENkGmpi3QXplVDBpv9Ci3i4L7rnZ2VPTjeKCIsMrbYg16dEl FkGN1Fs1S3DZFNR3i0faWwEDv1RdA4mUiHwygS2ZF7r8Yd9gwPCPfN+2qDfMnpuy 57MP3gj24VFlTw2J5SgK/h50ZzonAfWn6xroMO/aYTfTSAf+Ga1gABavBJz5x1Uu /e/8olYNVaPFig1aLvfd38RpSln6KXc3r/VdkmfXNwAI5Ma3OyoGXWnXPskZlW5S 7UlaXvAGQ6ALOdZ+3Vn4IFz35oV2h811UXuohdmnewBX2bR7KCqXdq3J9V1wFFjH A8su2kOhEauqIS4Rb6H8wCImnIvksW7FBzDpROKT+p2oU0d6FGMTnYS7G0MQQp/2 UF2IJBp6Dz9xSjEh9kJwGTqAFLQ/Gx+2HqTBfkfr8hNzgdO/DlCN+TuEUpYcQZf1 oCTukKbmOxDnXhYFPF73NqumBjXq2QJVGVta5AszvuISbSvhUxn7ALeEgeNMfGob uHA/GwYW2AqaCx0FRe6rmWZL6dg7go1QKi+qR50lTflbqho3vS8VoMDaFVBJ2Aox ty87r7zl7lES1rBHGJwn =k0jA -----END PGP SIGNATURE----- --A7dSUaxngFh2KEF6--