From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: [PATCH v5 1/2] drm/bridge: Add Cadence DSI driver Date: Mon, 29 Jan 2018 15:59:33 +0200 Message-ID: <07d82fcd-1e6c-37a8-36b7-d1a81cfeb2ae@ti.com> References: <20180118134309.13123-1-boris.brezillon@free-electrons.com> <9b45c6a3-f26b-59f5-d313-88290a2c5b42@ti.com> <20180129141409.0ec356d1@bbrezillon> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180129141409.0ec356d1@bbrezillon> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Boris Brezillon Cc: Archit Taneja , David Airlie , Daniel Vetter , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Richard Sproul , Simon Hatliff , Maxime Ripard , Thomas Petazzoni , Suresh Punnoose , Alan Douglas , "Menon, Nishanth" , Jyri Sarha , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrzej Hajda , Eric Anholt List-Id: devicetree@vger.kernel.org On 29/01/18 15:14, Boris Brezillon wrote: >> You don't disable the dsi_sys_clk neither in the ok nor in the error paths. > > Hm, it shouldn't be enabled in the first place: the runtime resume > hook takes care of enabling it, and we don't need this clock to access > IP registers (which is all we do in the probe). Ah, right, you can just use pm_runtime directly to enable the IP. I was looking at the docs, but it wasn't quite clear to me when exactly dsi_sys_clk is needed. I take it that you can access registers with just the dsi_p_clk, but you can't really do anything with the IP without dsi_sys_clk? If so, I think enabling both dsi_p_clk and dsi_sys_clk in the runtime PM callbacks is ok. Alternatively, if dsi_sys_clk is only needed for some specific functionality, a more correct way would be to enable that clock only when that operation is performed. Tomi -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html