From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH 1/6] dt-bindings: drm/panel: simple: Add no-hpd property Date: Thu, 25 Oct 2018 14:28:35 -0500 Message-ID: <20181025192835.GA30136@bogus> References: <20181022204639.8558-1-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <20181022204639.8558-1-dianders@chromium.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Douglas Anderson Cc: Mark Rutland , devicetree@vger.kernel.org, David Airlie , linux-arm-msm@vger.kernel.org, Sandeep Panda , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Thierry Reding , Sean Paul , Laurent Pinchart , ryandcase@chromium.org List-Id: linux-arm-msm@vger.kernel.org T24gTW9uLCBPY3QgMjIsIDIwMTggYXQgMDE6NDY6MzRQTSAtMDcwMCwgRG91Z2xhcyBBbmRlcnNv biB3cm90ZToKPiBTb21lIGVEUCBwYW5lbHMgdGhhdCBhcmUgZGVzaWduZWQgdG8gYmUgYWx3YXlz IGNvbm5lY3RlZCB0byBhIGJvYXJkCj4gdXNlIHRoZWlyIEhQRCBzaWduYWwgdG8gc2lnbmFsIHRo YXQgdGhleSd2ZSBmaW5pc2hlZCBwb3dlcmluZyBvbiBhbmQKPiB0aGV5J3JlIHJlYWR5IHRvIGJl IHRhbGtlZCB0by4KPiAKPiBIb3dldmVyLCBmb3IgdmFyaW91cyByZWFzb25zIGl0J3MgcG9zc2li bGUgdGhhdCB0aGUgSFBEIHNpZ25hbCBmcm9tCj4gdGhlIHBhbmVsIGlzbid0IGFjdHVhbGx5IGhv b2tlZCB1cC4gIEluIHRoZSBjYXNlIHdoZXJlIHRoZSBIUEQgaXNuJ3QKPiBob29rZWQgdXAgeW91 IGNhbiBsb29rIGF0IHRoZSB0aW1pbmcgZGlhZ3JhbSBvbiB0aGUgcGFuZWwgZGF0YXNoZWV0Cj4g YW5kIGluc2VydCBhIGRlbGF5IGZvciB0aGUgbWF4aW11bSBhbW91bnQgb2YgdGltZSB0aGF0IHRo ZSBIUEQgbWlnaHQKPiB0YWtlIHRvIGNvbWUgdXAuCj4gCj4gTGV0J3MgYWRkIGEgcHJvcGVydHkg aW4gdGhlIGRldmljZSB0cmVlIGZvciB0aGlzIGNvbmNlcHQuCj4gCj4gU2lnbmVkLW9mZi1ieTog RG91Z2xhcyBBbmRlcnNvbiA8ZGlhbmRlcnNAY2hyb21pdW0ub3JnPgo+IC0tLQo+IAo+ICAuLi4v ZGV2aWNldHJlZS9iaW5kaW5ncy9kaXNwbGF5L3BhbmVsL3NpbXBsZS1wYW5lbC50eHQgICAgICAg ICB8IDMgKysrCj4gIDEgZmlsZSBjaGFuZ2VkLCAzIGluc2VydGlvbnMoKykKPiAKPiBkaWZmIC0t Z2l0IGEvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVlL2JpbmRpbmdzL2Rpc3BsYXkvcGFuZWwvc2lt cGxlLXBhbmVsLnR4dCBiL0RvY3VtZW50YXRpb24vZGV2aWNldHJlZS9iaW5kaW5ncy9kaXNwbGF5 L3BhbmVsL3NpbXBsZS1wYW5lbC50eHQKPiBpbmRleCA0NWE0NTdhZDM4ZjAuLmIyYjg3MmM3MTBm MiAxMDA2NDQKPiAtLS0gYS9Eb2N1bWVudGF0aW9uL2RldmljZXRyZWUvYmluZGluZ3MvZGlzcGxh eS9wYW5lbC9zaW1wbGUtcGFuZWwudHh0Cj4gKysrIGIvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVl L2JpbmRpbmdzL2Rpc3BsYXkvcGFuZWwvc2ltcGxlLXBhbmVsLnR4dAo+IEBAIC0xMSw2ICsxMSw5 IEBAIE9wdGlvbmFsIHByb3BlcnRpZXM6Cj4gIC0gZGRjLWkyYy1idXM6IHBoYW5kbGUgb2YgYW4g STJDIGNvbnRyb2xsZXIgdXNlZCBmb3IgRERDIEVESUQgcHJvYmluZwo+ICAtIGVuYWJsZS1ncGlv czogR1BJTyBwaW4gdG8gZW5hYmxlIG9yIGRpc2FibGUgdGhlIHBhbmVsCj4gIC0gYmFja2xpZ2h0 OiBwaGFuZGxlIG9mIHRoZSBiYWNrbGlnaHQgZGV2aWNlIGF0dGFjaGVkIHRvIHRoZSBwYW5lbAo+ ICstIG5vLWhwZDogVGhpcyBwYW5lbCBpcyBzdXBwb3NlZCB0byBjb21tdW5pY2F0ZSB0aGF0IGl0 J3MgcmVhZHkgdmlhIEhQRAo+ICsgIChob3QgcGx1ZyBkZXRlY3QpIHNpZ25hbCwgYnV0IHRoZSBz aWduYWwgaXNuJ3QgaG9va2VkIHVwIHNvIHdlIHNob3VsZAo+ICsgIGhhcmRjb2RlIHRoZSBtYXgg ZGVsYXkgZnJvbSB0aGUgcGFuZWwgc3BlYyB3aGVuIHBvd2VyaW5nIHVwIHRoZSBwYW5lbC4KCklm IHdlIGhhdmUgdGhpcyBoZXJlLCB0aGVuIHdlIHNob3VsZCBhbHNvIGhhdmUgaHBkLWdwaW9zIGRl ZmluZWQgaGVyZSBhcyAKd2hlcmUgd2UgZGVzY3JpYmUgYSBjb25uZWN0aW9uIHdlIHNob3VsZCBh bHNvIGRlc2NyaWJlIG5vIGNvbm5lY3Rpb24uCgpOb3csIGhwZC1ncGlvcyBpcyBhIGJpdCBvZiBh IG1lc3MgYmVpbmcgZGVmaW5lZCBpbiBib3RoIGNvbm5lY3RvciBub2RlcyAKYW5kIGJyaWRnZSAo SERNSS9EUCkgbm9kZXMuIEkgdGhpbmsgdGhhdCBpcyBqdXN0IGhpc3RvcnkgcHJlLWRhdGluZyAK Y29ubmVjdG9yIG5vZGVzLiBDb25uZWN0b3Igbm9kZXMgYXJlIG5vdyB0aGUgcHJlZmVycmVkIHBs YWNlLiBDb25uZWN0b3IgCm5vZGVzIGFuZCBwYW5lbCBub2RlcyBhcmUgZXNzZW50aWFsbHkgdGhl IHNhbWUgdGhpbmcgKHRoZSBlbmRwb2ludCBvZiAKZGlzcGxheSBwaXBlbGluZSkuCgpUaGF0IGJl aW5nIHNhaWQsIHRoaXMgcGF0Y2ggaXMgZmluZSBhcyBpcy4KClJldmlld2VkLWJ5OiBSb2IgSGVy cmluZyA8cm9iaEBrZXJuZWwub3JnPgoKUm9iCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3Rz LmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xp c3RpbmZvL2RyaS1kZXZlbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0EEFC46475 for ; 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[24.155.109.49]) by smtp.gmail.com with ESMTPSA id r143-v6sm1780767oie.27.2018.10.25.12.28.36 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 25 Oct 2018 12:28:36 -0700 (PDT) Date: Thu, 25 Oct 2018 14:28:35 -0500 From: Rob Herring To: Douglas Anderson Cc: Sean Paul , Thierry Reding , Sandeep Panda , linux-arm-msm@vger.kernel.org, Laurent Pinchart , jsanka@codeaurora.org, ryandcase@chromium.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, David Airlie , Mark Rutland Subject: Re: [PATCH 1/6] dt-bindings: drm/panel: simple: Add no-hpd property Message-ID: <20181025192835.GA30136@bogus> References: <20181022204639.8558-1-dianders@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181022204639.8558-1-dianders@chromium.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 22, 2018 at 01:46:34PM -0700, Douglas Anderson wrote: > Some eDP panels that are designed to be always connected to a board > use their HPD signal to signal that they've finished powering on and > they're ready to be talked to. > > However, for various reasons it's possible that the HPD signal from > the panel isn't actually hooked up. In the case where the HPD isn't > hooked up you can look at the timing diagram on the panel datasheet > and insert a delay for the maximum amount of time that the HPD might > take to come up. > > Let's add a property in the device tree for this concept. > > Signed-off-by: Douglas Anderson > --- > > .../devicetree/bindings/display/panel/simple-panel.txt | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/Documentation/devicetree/bindings/display/panel/simple-panel.txt b/Documentation/devicetree/bindings/display/panel/simple-panel.txt > index 45a457ad38f0..b2b872c710f2 100644 > --- a/Documentation/devicetree/bindings/display/panel/simple-panel.txt > +++ b/Documentation/devicetree/bindings/display/panel/simple-panel.txt > @@ -11,6 +11,9 @@ Optional properties: > - ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing > - enable-gpios: GPIO pin to enable or disable the panel > - backlight: phandle of the backlight device attached to the panel > +- no-hpd: This panel is supposed to communicate that it's ready via HPD > + (hot plug detect) signal, but the signal isn't hooked up so we should > + hardcode the max delay from the panel spec when powering up the panel. If we have this here, then we should also have hpd-gpios defined here as where we describe a connection we should also describe no connection. Now, hpd-gpios is a bit of a mess being defined in both connector nodes and bridge (HDMI/DP) nodes. I think that is just history pre-dating connector nodes. Connector nodes are now the preferred place. Connector nodes and panel nodes are essentially the same thing (the endpoint of display pipeline). That being said, this patch is fine as is. Reviewed-by: Rob Herring Rob