From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCH v2 2/2] drm/bridge: sii902x: add optional power supplies Date: Tue, 15 May 2018 10:36:30 +0300 Message-ID: <2814752.ZM2IG9T3fV@avalon> References: <20180425075314.19137-1-philippe.cornu@st.com> <69a9da79-63df-6d0a-52e3-729ec8937484@samsung.com> <8ed2cfcd-df26-fa9c-c45d-7bf4020f0faa@st.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <8ed2cfcd-df26-fa9c-c45d-7bf4020f0faa@st.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Philippe CORNU Cc: Mark Rutland , "devicetree@vger.kernel.org" , Alexandre TORGUE , David Airlie , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , Yannick FERTRE , Rob Herring List-Id: devicetree@vger.kernel.org SGkgUGhpbGlwcGUsCgpPbiBNb25kYXksIDE0IE1heSAyMDE4IDIxOjU4OjQ4IEVFU1QgUGhpbGlw cGUgQ09STlUgd3JvdGU6Cj4gT24gMDUvMTQvMjAxOCAxMjozMyBQTSwgQW5kcnplaiBIYWpkYSB3 cm90ZToKPiA+IE9uIDE0LjA1LjIwMTggMTE6MzgsIFBoaWxpcHBlIENPUk5VIHdyb3RlOgo+ID4+ IE9uIDA0LzI1LzIwMTggMDk6NTMgQU0sIFBoaWxpcHBlIENvcm51IHdyb3RlOgo+ID4+PiBBZGQg dGhlIG9wdGlvbmFsIHBvd2VyIHN1cHBsaWVzIHVzaW5nIHRoZSBkZXNjcmlwdGlvbiBmb3VuZCBp bgo+ID4+PiAiU2lJOTAyMkEvU2lJOTAyNEEgSERNSSBUcmFuc21pdHRlciBEYXRhIFNoZWV0IChB dWd1c3QgMjAxNikiLgo+ID4+Pgo+ID4+PiBUaGUgc2lpOTAyeCBpbnB1dCBJT3MgYXJlIG5vdCAi aW8gc2FmZSIgc28gaXQgaXMgaW1wb3J0YW50IHRvCj4gPj4+IGVuYWJsZS9kaXNhYmxlIHZvbHRh Z2UgcmVndWxhdG9ycyBkdXJpbmcgcHJvYmUvcmVtb3ZlIHBoYXNlcyB0bwo+ID4+PiBhdm9pZCBk YW1hZ2VzLgo+ID4gCj4gPiBXaGF0IGV4YWN0bHkgZG9lcyBpdCBtZWFuPyBJZSBJIHVuZGVyc3Rh bmQgdGhhdCB0aGUgY2hpcCBoYXMgc29tZQo+ID4gbGltaXRhdGlvbnMsIGJ1dCB3aHkgZW5hYmxp bmcvZGlzYWJsaW5nIHJlZ3VsYXRvcnMgaW4gcHJvYmUvcmVtb3ZlCj4gPiBzaG91bGQgc29sdmUg aXQ/Cj4gCj4gdGhhbmsgeW91IGZvciB5b3VyIGNvbW1lbnQuCj4gCj4gQW5kIHNvcnJ5IGZvciB0 aGUgImJhZCIgZXhwbGFuYXRpb24gaW4gdGhlIDJuZCBwYXJhZ3JhcGggYWJvdXQgdGhlIGZhY3Qg Cj4gdGhhdCBpbnB1dHMgYXJlIG5vdCAiaW8gc2FmZSIuIEkgYWRkZWQgdGhpcyAybmQgcGFyYWdy YXBoIGluIHYyIAo+IGZvbGxvd2luZyBhIGdvb2QgY29tbWVudCBmcm9tIExhdXJlbnQgb24gYWRk aW5nIHRoZSBtYW5hZ2VtZW50IG9mIHRoZSAKPiByZWd1bGF0b3JzIG91dHNpZGUgdGhlIHByb2Jl L3JlbW92ZSBmb3IgYSBiZXR0ZXIgcG93ZXIgY29uc3VtcHRpb24gCj4gbWFuYWdlbWVudCAoZW5h YmxlL2Rpc2FibGUgcmVndWxhdG9ycyBvbmx5IHdoZW4gdGhlIGljIGlzIHVzZWQgZm9yIAo+IGRp c3BsYXlpbmcgc29tZXRoaW5nIGZvciBpbnN0YW5jZS4uLikuIEJ1dCBhZnRlciBhIGRlZXBlciBh bmFseXNpcywgSSAKPiByZWFsaXplZCB0aGF0IHRoZSBvbmx5IHdheSB0byBpbXByb3ZlIHRoZSBw b3dlciBjb25zdW1wdGlvbiBpcyB0byAKPiBpbXBsZW1lbnQgJiB0ZXN0IHRoZSBzaWk5MDJ4IHZh cmlvdXMgc2xlZXAgbW9kZXMsIHRoYXQgaXMgb3V0LW9mLXNjb3BlIAo+IG9mIHRoaXMgc21hbGwg cGF0Y2ggYW5kIGFsc28gb3V0LW9mLXNjb3BlIG9mIG15IHRlc3QgYm9hcmQgSSB1c2Ugb24gCj4g d2hpY2ggdGhlIHNpaTkwMnggYnJpZGdlIGljIHBvd2VyIGNvbnN1bXB0aW9uIGlzIHZlcnkgbG93 IGNvbXBhcmUgdG8gdGhlIAo+IHJlc3Qgb2YgdGhlIHN5c3RlbS4uLgo+IAo+IEkgd2lsbCByZW1v dmUgdGhpcyAiZXhwbGFuYXRpb24iIGluIHYzIGFzIGl0IGNyZWF0ZXMgY29uZnVzaW9uLgoKSSdk IHJhdGhlciBrZWVwIGl0IGFuZCBleHBhbmQgaXQgZXhwbGFpbiB3aHkgZW5hYmxpbmcvZGlzYWJs aW5nIHJlZ3VsYXRvcnMgYXQgCnByb2JlL3JlbW92ZSBzb2x2ZXMgdGhlIHByb2JsZW0uIFlvdXIg cGF0Y2ggb3RoZXJ3aXNlIGxvb2tzIE9LIChhbHRob3VnaCBpZiAKeW91IHN1Ym1pdCBhIHYzIGFu eXdheSB5b3UgY291bGQgYWxzbyByZW5hbWUgZXJyX2Rpc2FibGVfcmVndWxhdG9yIHRvIAplcnJf ZGlzYWJsZV9yZWd1bGF0b3JzKS4KCj4gPj4+IFNpZ25lZC1vZmYtYnk6IFBoaWxpcHBlIENvcm51 IDxwaGlsaXBwZS5jb3JudUBzdC5jb20+Cj4gPj4+IC0tLQo+ID4+PiAKPiA+Pj4gZHJpdmVycy9n cHUvZHJtL2JyaWRnZS9zaWk5MDJ4LmMgfCAzOCArKysrKysrKysrKysrKysrKysrKysrKysrKysr KystLS0tCj4gPj4+IDEgZmlsZSBjaGFuZ2VkLCAzNCBpbnNlcnRpb25zKCspLCA0IGRlbGV0aW9u cygtKQoKLS0gClJlZ2FyZHMsCgpMYXVyZW50IFBpbmNoYXJ0CgoKCl9fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJp LWRldmVsQGxpc3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9y Zy9tYWlsbWFuL2xpc3RpbmZvL2RyaS1kZXZlbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752379AbeEOHgQ (ORCPT ); Tue, 15 May 2018 03:36:16 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:52022 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752168AbeEOHgP (ORCPT ); Tue, 15 May 2018 03:36:15 -0400 From: Laurent Pinchart To: Philippe CORNU Cc: Andrzej Hajda , Archit Taneja , David Airlie , Rob Herring , Mark Rutland , "dri-devel@lists.freedesktop.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Yannick FERTRE , Benjamin Gaignard , Alexandre TORGUE Subject: Re: [PATCH v2 2/2] drm/bridge: sii902x: add optional power supplies Date: Tue, 15 May 2018 10:36:30 +0300 Message-ID: <2814752.ZM2IG9T3fV@avalon> Organization: Ideas on Board Oy In-Reply-To: <8ed2cfcd-df26-fa9c-c45d-7bf4020f0faa@st.com> References: <20180425075314.19137-1-philippe.cornu@st.com> <69a9da79-63df-6d0a-52e3-729ec8937484@samsung.com> <8ed2cfcd-df26-fa9c-c45d-7bf4020f0faa@st.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Philippe, On Monday, 14 May 2018 21:58:48 EEST Philippe CORNU wrote: > On 05/14/2018 12:33 PM, Andrzej Hajda wrote: > > On 14.05.2018 11:38, Philippe CORNU wrote: > >> On 04/25/2018 09:53 AM, Philippe Cornu wrote: > >>> Add the optional power supplies using the description found in > >>> "SiI9022A/SiI9024A HDMI Transmitter Data Sheet (August 2016)". > >>> > >>> The sii902x input IOs are not "io safe" so it is important to > >>> enable/disable voltage regulators during probe/remove phases to > >>> avoid damages. > > > > What exactly does it mean? Ie I understand that the chip has some > > limitations, but why enabling/disabling regulators in probe/remove > > should solve it? > > thank you for your comment. > > And sorry for the "bad" explanation in the 2nd paragraph about the fact > that inputs are not "io safe". I added this 2nd paragraph in v2 > following a good comment from Laurent on adding the management of the > regulators outside the probe/remove for a better power consumption > management (enable/disable regulators only when the ic is used for > displaying something for instance...). But after a deeper analysis, I > realized that the only way to improve the power consumption is to > implement & test the sii902x various sleep modes, that is out-of-scope > of this small patch and also out-of-scope of my test board I use on > which the sii902x bridge ic power consumption is very low compare to the > rest of the system... > > I will remove this "explanation" in v3 as it creates confusion. I'd rather keep it and expand it explain why enabling/disabling regulators at probe/remove solves the problem. Your patch otherwise looks OK (although if you submit a v3 anyway you could also rename err_disable_regulator to err_disable_regulators). > >>> Signed-off-by: Philippe Cornu > >>> --- > >>> > >>> drivers/gpu/drm/bridge/sii902x.c | 38 ++++++++++++++++++++++++++++++---- > >>> 1 file changed, 34 insertions(+), 4 deletions(-) -- Regards, Laurent Pinchart