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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D20E2C433EF for ; Wed, 9 Mar 2022 08:18:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230318AbiCIITR (ORCPT ); Wed, 9 Mar 2022 03:19:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229955AbiCIITR (ORCPT ); Wed, 9 Mar 2022 03:19:17 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0A791CB1C for ; Wed, 9 Mar 2022 00:18:17 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nRrWQ-0000mv-AP; Wed, 09 Mar 2022 09:18:14 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nRrWM-0007ek-O8; Wed, 09 Mar 2022 09:18:10 +0100 Date: Wed, 9 Mar 2022 09:18:10 +0100 From: Sascha Hauer To: "zhangqing@rock-chips.com" Cc: =?utf-8?B?6Zer5a2d5Yab?= , Dmitry Osipenko , "robin.murphy" , =?utf-8?B?5byg5pm0?= , huangtao , devicetree , =?utf-8?B?5pON55Ge5p2w?= , Benjamin Gaignard , pgwipeout , hjc , dri-devel , =?utf-8?B?5p2o5Yev?= , linux-rockchip , Michael Riesch , kernel , Dmitry Osipenko , linux-arm-kernel Subject: Re: Re: [PATCH v7 10/24] drm/rockchip: dw_hdmi: Add support for hclk Message-ID: <20220309081810.GH405@pengutronix.de> References: <78207d97-b5a1-9792-8ec9-11fcf2e00370@gmail.com> <90c61299-f02c-607b-4734-7134852ef0a6@arm.com> <20220225131154.GE19585@pengutronix.de> <20220228141921.GN19585@pengutronix.de> <5184ecf2-8734-3121-cbbc-5dcfcf0d02f8@arm.com> <20220302112528.GV19585@pengutronix.de> <20220304142235.GL22780@pengutronix.de> <9ea0134e-aac7-60e1-5c58-ae31b4e1c422@collabora.com> <035f2dfd-bf35-abca-32bf-2be85cc88f8a@rock-chips.com> <20220309094139198367142@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220309094139198367142@rock-chips.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 08:57:51 up 88 days, 16:43, 82 users, load average: 0.00, 0.03, 0.08 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Elaine, On Wed, Mar 09, 2022 at 09:41:39AM +0800, zhangqing@rock-chips.com wrote: > hi，all： > Let me explain the clock dependency： > From the clock tree, pclk_vo0 and hclk_vo0 are completely independent > clocks with different parent clocks and different clock frequencies。 > But the niu path is : > pclk_vo is dependent on hclk_vo, and the pclk_vo niu goes through  hclk_vo > niu. Thanks, this is the information we are looking for. What is "NIU" btw? I think this is even documented in the Reference Manual. With the right pointer I just found: > A part of niu clocks have a dependence on another niu clock in order to > sharing the internal bus. When these clocks are in use, another niu > clock must be opened, and cannot be gated. These clocks and the special > clock on which they are relied are as following: > > Clocks which have dependency The clock which can not be gated > ----------------------------------------------------------------- > ... > pclk_vo_niu, hclk_vo_s_niu hclk_vo_niu > ... > The clock tree and NIU bus paths are designed independently > So there are three solutions to this problem: > 1. DTS adds a reference to Hclk while referencing Pclk. > 2, The dependent clock is always on, such as HCLK_VO0, but this is not > friendly for the system power. > 3. Create a non-clock-tree reference. Clk-link, for example, we have an > implementation in our internal branch, but Upstream is not sure how to > push it. I thought about something similar. That would help us here and on i.MX we have a similar situation: We have one bit that switches multiple clocks. That as well cannot be designed properly in the clock framework currently, but could be modelled with a concept of linked clocks. Doing this sounds like quite a bit of work and discussion though, I don't really like having this as a dependency to mainline the VOP2 driver. I vote for 1. in that case, we could still ignore the hclk in dts later when we have linked clocks. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6C8BCC433EF for ; Wed, 9 Mar 2022 08:18:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=UUeW5J/4oH1cldxGWGFbDU+NcZjIkKu4il33B2q4NqA=; b=tdGOH3+T/cyA85 i2lZhMMwLp2NwAJXDi1Y/EGSK3EBwIRHnuGO93LJC7259Ffd/nWTqtYkgSrC1Q+CNsypPeqOe66Oi DWS9ERTD9CnfdgywL6LEA6ioQiWwTxSfWPEawdkCBNLjfIz7ZyObbg4G6zXKnTIWRyyxmTL2yEPID jlDhI1SszBGsi9nXCTeeSxTDCzaonh/EB7se3NEyi7P4ftfCC1hjUClmCvvLFCm2JZCGTUDL84xzu xUrKYrbcLY4zNSLBX2heistTZRbCHg0Ymzvf2OCHcAmZdiNd31LDkzcwhp3YlhFZ7/5R32ZCnn9/o DZf3TcaeLyBS1OgS4wSA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRrX2-007jKJ-7y; Wed, 09 Mar 2022 08:18:52 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRrWn-007jGU-Jv for linux-rockchip@lists.infradead.org; Wed, 09 Mar 2022 08:18:39 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nRrWQ-0000mv-AP; Wed, 09 Mar 2022 09:18:14 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nRrWM-0007ek-O8; Wed, 09 Mar 2022 09:18:10 +0100 Date: Wed, 9 Mar 2022 09:18:10 +0100 From: Sascha Hauer To: "zhangqing@rock-chips.com" Cc: =?utf-8?B?6Zer5a2d5Yab?= , Dmitry Osipenko , "robin.murphy" , =?utf-8?B?5byg5pm0?= , huangtao , devicetree , =?utf-8?B?5pON55Ge5p2w?= , Benjamin Gaignard , pgwipeout , hjc , dri-devel , =?utf-8?B?5p2o5Yev?= , linux-rockchip , Michael Riesch , kernel , Dmitry Osipenko , linux-arm-kernel Subject: Re: Re: [PATCH v7 10/24] drm/rockchip: dw_hdmi: Add support for hclk Message-ID: <20220309081810.GH405@pengutronix.de> References: <78207d97-b5a1-9792-8ec9-11fcf2e00370@gmail.com> <90c61299-f02c-607b-4734-7134852ef0a6@arm.com> <20220225131154.GE19585@pengutronix.de> <20220228141921.GN19585@pengutronix.de> <5184ecf2-8734-3121-cbbc-5dcfcf0d02f8@arm.com> <20220302112528.GV19585@pengutronix.de> <20220304142235.GL22780@pengutronix.de> <9ea0134e-aac7-60e1-5c58-ae31b4e1c422@collabora.com> <035f2dfd-bf35-abca-32bf-2be85cc88f8a@rock-chips.com> <20220309094139198367142@rock-chips.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220309094139198367142@rock-chips.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 08:57:51 up 88 days, 16:43, 82 users, load average: 0.00, 0.03, 0.08 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-rockchip@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220309_001837_665499_B9AC9E54 X-CRM114-Status: GOOD ( 30.35 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org SGkgRWxhaW5lLAoKT24gV2VkLCBNYXIgMDksIDIwMjIgYXQgMDk6NDE6MzlBTSArMDgwMCwgemhh bmdxaW5nQHJvY2stY2hpcHMuY29tIHdyb3RlOgo+ICAgIGhp77yMYWxs77yaCj4gICAgTGV0IG1l IGV4cGxhaW4gdGhlIGNsb2NrIGRlcGVuZGVuY3nvvJoKPiAgICBGcm9tIHRoZSBjbG9jayB0cmVl LCBwY2xrX3ZvMCBhbmQgaGNsa192bzAgYXJlIGNvbXBsZXRlbHkgaW5kZXBlbmRlbnQKPiAgICBj bG9ja3Mgd2l0aCBkaWZmZXJlbnQgcGFyZW50IGNsb2NrcyBhbmQgZGlmZmVyZW50IGNsb2NrIGZy ZXF1ZW5jaWVz44CCCj4gICAgQnV0IHRoZSBuaXXCoHBhdGjCoGlzIDoKPiAgICBwY2xrX3ZvIGlz IGRlcGVuZGVudCBvbiBoY2xrX3ZvLCBhbmQgdGhlIHBjbGtfdm8gbml1IGdvZXMgdGhyb3VnaMKg IGhjbGtfdm8KPiAgICBuaXUuCgpUaGFua3MsIHRoaXMgaXMgdGhlIGluZm9ybWF0aW9uIHdlIGFy ZSBsb29raW5nIGZvci4gV2hhdCBpcyAiTklVIiBidHc/CkkgdGhpbmsgdGhpcyBpcyBldmVuIGRv Y3VtZW50ZWQgaW4gdGhlIFJlZmVyZW5jZSBNYW51YWwuIFdpdGggdGhlIHJpZ2h0CnBvaW50ZXIg SSBqdXN0IGZvdW5kOgoKPiBBIHBhcnQgb2Ygbml1IGNsb2NrcyBoYXZlIGEgZGVwZW5kZW5jZSBv biBhbm90aGVyIG5pdSBjbG9jayBpbiBvcmRlciB0bwo+IHNoYXJpbmcgdGhlIGludGVybmFsIGJ1 cy4gV2hlbiB0aGVzZSBjbG9ja3MgYXJlIGluIHVzZSwgYW5vdGhlciBuaXUKPiBjbG9jayBtdXN0 IGJlIG9wZW5lZCwgYW5kIGNhbm5vdCBiZSBnYXRlZC4gIFRoZXNlIGNsb2NrcyBhbmQgdGhlIHNw ZWNpYWwKPiBjbG9jayBvbiB3aGljaCB0aGV5IGFyZSByZWxpZWQgYXJlIGFzIGZvbGxvd2luZzoK Pgo+IENsb2NrcyB3aGljaCBoYXZlIGRlcGVuZGVuY3kgICAgIFRoZSBjbG9jayB3aGljaCBjYW4g bm90IGJlIGdhdGVkCj4gLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0KPiAuLi4KPiBwY2xrX3ZvX25pdSwgaGNsa192b19zX25p dSAgICAgICBoY2xrX3ZvX25pdQo+IC4uLgoKCgo+ICAgIFRoZSBjbG9jayB0cmVlIGFuZCBOSVUg YnVzIHBhdGhzIGFyZSBkZXNpZ25lZCBpbmRlcGVuZGVudGx5Cj4gICAgU28gdGhlcmUgYXJlIHRo cmVlIHNvbHV0aW9ucyB0byB0aGlzIHByb2JsZW06Cj4gICAgMS4gRFRTIGFkZHMgYSByZWZlcmVu Y2UgdG8gSGNsayB3aGlsZSByZWZlcmVuY2luZyBQY2xrLgo+ICAgIDIsIFRoZSBkZXBlbmRlbnQg Y2xvY2sgaXMgYWx3YXlzIG9uLCBzdWNoIGFzIEhDTEtfVk8wLMKgYnV0IHRoaXMgaXMgbm90Cj4g ICAgZnJpZW5kbHkgZm9yIHRoZSBzeXN0ZW0gcG93ZXIuCj4gICAgMy4gQ3JlYXRlIGEgbm9uLWNs b2NrLXRyZWUgcmVmZXJlbmNlLsKgQ2xrLWxpbmssIGZvciBleGFtcGxlLCB3ZSBoYXZlIGFuCj4g ICAgaW1wbGVtZW50YXRpb24gaW4gb3VyIGludGVybmFsIGJyYW5jaCwgYnV0IFVwc3RyZWFtIGlz IG5vdCBzdXJlIGhvdyB0bwo+ICAgIHB1c2ggaXQuCgpJIHRob3VnaHQgYWJvdXQgc29tZXRoaW5n IHNpbWlsYXIuIFRoYXQgd291bGQgaGVscCB1cyBoZXJlIGFuZCBvbiBpLk1YCndlIGhhdmUgYSBz aW1pbGFyIHNpdHVhdGlvbjogV2UgaGF2ZSBvbmUgYml0IHRoYXQgc3dpdGNoZXMgbXVsdGlwbGUK Y2xvY2tzLiBUaGF0IGFzIHdlbGwgY2Fubm90IGJlIGRlc2lnbmVkIHByb3Blcmx5IGluIHRoZSBj bG9jayBmcmFtZXdvcmsKY3VycmVudGx5LCBidXQgY291bGQgYmUgbW9kZWxsZWQgd2l0aCBhIGNv bmNlcHQgb2YgbGlua2VkIGNsb2Nrcy4KCkRvaW5nIHRoaXMgc291bmRzIGxpa2UgcXVpdGUgYSBi aXQgb2Ygd29yayBhbmQgZGlzY3Vzc2lvbiB0aG91Z2gsIEkKZG9uJ3QgcmVhbGx5IGxpa2UgaGF2 aW5nIHRoaXMgYXMgYSBkZXBlbmRlbmN5IHRvIG1haW5saW5lIHRoZSBWT1AyCmRyaXZlci4gSSB2 b3RlIGZvciAxLiBpbiB0aGF0IGNhc2UsIHdlIGNvdWxkIHN0aWxsIGlnbm9yZSB0aGUgaGNsayBp bgpkdHMgbGF0ZXIgd2hlbiB3ZSBoYXZlIGxpbmtlZCBjbG9ja3MuCgpTYXNjaGEKCi0tIApQZW5n dXRyb25peCBlLksuICAgICAgICAgICAgICAgICAgICAgICAgICAgfCAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgfApTdGV1ZXJ3YWxkZXIgU3RyLiAyMSAgICAgICAgICAgICAgICAgICAgICAg fCBodHRwOi8vd3d3LnBlbmd1dHJvbml4LmRlLyAgfAozMTEzNyBIaWxkZXNoZWltLCBHZXJtYW55 ICAgICAgICAgICAgICAgICAgfCBQaG9uZTogKzQ5LTUxMjEtMjA2OTE3LTAgICAgfApBbXRzZ2Vy aWNodCBIaWxkZXNoZWltLCBIUkEgMjY4NiAgICAgICAgICAgfCBGYXg6ICAgKzQ5LTUxMjEtMjA2 OTE3LTU1NTUgfAoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X18KTGludXgtcm9ja2NoaXAgbWFpbGluZyBsaXN0CkxpbnV4LXJvY2tjaGlwQGxpc3RzLmluZnJh ZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9saW51 eC1yb2NrY2hpcAo= 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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BEDBCC433F5 for ; Wed, 9 Mar 2022 08:18:20 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D651C10E928; Wed, 9 Mar 2022 08:18:19 +0000 (UTC) Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by gabe.freedesktop.org (Postfix) with ESMTPS id 28F4110E914 for ; Wed, 9 Mar 2022 08:18:18 +0000 (UTC) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nRrWQ-0000mv-AP; Wed, 09 Mar 2022 09:18:14 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nRrWM-0007ek-O8; Wed, 09 Mar 2022 09:18:10 +0100 Date: Wed, 9 Mar 2022 09:18:10 +0100 From: Sascha Hauer To: "zhangqing@rock-chips.com" Subject: Re: Re: [PATCH v7 10/24] drm/rockchip: dw_hdmi: Add support for hclk Message-ID: <20220309081810.GH405@pengutronix.de> References: <78207d97-b5a1-9792-8ec9-11fcf2e00370@gmail.com> <90c61299-f02c-607b-4734-7134852ef0a6@arm.com> <20220225131154.GE19585@pengutronix.de> <20220228141921.GN19585@pengutronix.de> <5184ecf2-8734-3121-cbbc-5dcfcf0d02f8@arm.com> <20220302112528.GV19585@pengutronix.de> <20220304142235.GL22780@pengutronix.de> <9ea0134e-aac7-60e1-5c58-ae31b4e1c422@collabora.com> <035f2dfd-bf35-abca-32bf-2be85cc88f8a@rock-chips.com> <20220309094139198367142@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220309094139198367142@rock-chips.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 08:57:51 up 88 days, 16:43, 82 users, load average: 0.00, 0.03, 0.08 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: dri-devel@lists.freedesktop.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: huangtao , devicetree , =?utf-8?B?5pON55Ge5p2w?= , Benjamin Gaignard , pgwipeout , hjc , dri-devel , =?utf-8?B?5p2o5Yev?= , linux-rockchip , Michael Riesch , Dmitry Osipenko , =?utf-8?B?5byg5pm0?= , =?utf-8?B?6Zer5a2d5Yab?= , Dmitry Osipenko , "robin.murphy" , kernel , linux-arm-kernel Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Elaine, On Wed, Mar 09, 2022 at 09:41:39AM +0800, zhangqing@rock-chips.com wrote: > hi，all： > Let me explain the clock dependency： > From the clock tree, pclk_vo0 and hclk_vo0 are completely independent > clocks with different parent clocks and different clock frequencies。 > But the niu path is : > pclk_vo is dependent on hclk_vo, and the pclk_vo niu goes through  hclk_vo > niu. Thanks, this is the information we are looking for. What is "NIU" btw? I think this is even documented in the Reference Manual. With the right pointer I just found: > A part of niu clocks have a dependence on another niu clock in order to > sharing the internal bus. When these clocks are in use, another niu > clock must be opened, and cannot be gated. These clocks and the special > clock on which they are relied are as following: > > Clocks which have dependency The clock which can not be gated > ----------------------------------------------------------------- > ... > pclk_vo_niu, hclk_vo_s_niu hclk_vo_niu > ... > The clock tree and NIU bus paths are designed independently > So there are three solutions to this problem: > 1. DTS adds a reference to Hclk while referencing Pclk. > 2, The dependent clock is always on, such as HCLK_VO0, but this is not > friendly for the system power. > 3. Create a non-clock-tree reference. Clk-link, for example, we have an > implementation in our internal branch, but Upstream is not sure how to > push it. I thought about something similar. That would help us here and on i.MX we have a similar situation: We have one bit that switches multiple clocks. That as well cannot be designed properly in the clock framework currently, but could be modelled with a concept of linked clocks. Doing this sounds like quite a bit of work and discussion though, I don't really like having this as a dependency to mainline the VOP2 driver. I vote for 1. in that case, we could still ignore the hclk in dts later when we have linked clocks. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B160EC433F5 for ; Wed, 9 Mar 2022 08:20:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pCRiIyk2VbrTp0Wm49QiA/LjYxKERmvZFQfn6h3NG/A=; b=AXo5yG9Cvlc+2t jznpxAn/nFxKHa3GSyy/k6y2vgjGt3HwUbYOE5jBmCsCFS5u55aDcHFJ0nxtOUo9Pk1Hn2023hflw Whq+OLpEn90Bw3ACDw5yORkxo7lv/+tbViiNECUL4/r64+S+dl3fIZqCDLY9ZSXj9QI6bobKUNGJx uRXTJ//1JD6HcU1eFufYEVI6vpBmn2i85fbwApQWw7Hn9/hSbC0tjmX3+cCP1OCHGjfZ4hpSL9Uln vfWOw+RUUpck9mt5sqYQZHjF+xue/A1WJyO/wCwc2fQKVNY0k05yjT89pl5QTs1yTQsDIUebpkDip 99MpIypHoqRTrU9XWrjg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRrWs-007jI4-1u; Wed, 09 Mar 2022 08:18:42 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRrWn-007jGb-Jh for linux-arm-kernel@lists.infradead.org; Wed, 09 Mar 2022 08:18:39 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nRrWQ-0000mv-AP; Wed, 09 Mar 2022 09:18:14 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nRrWM-0007ek-O8; Wed, 09 Mar 2022 09:18:10 +0100 Date: Wed, 9 Mar 2022 09:18:10 +0100 From: Sascha Hauer To: "zhangqing@rock-chips.com" Cc: =?utf-8?B?6Zer5a2d5Yab?= , Dmitry Osipenko , "robin.murphy" , =?utf-8?B?5byg5pm0?= , huangtao , devicetree , =?utf-8?B?5pON55Ge5p2w?= , Benjamin Gaignard , pgwipeout , hjc , dri-devel , =?utf-8?B?5p2o5Yev?= , linux-rockchip , Michael Riesch , kernel , Dmitry Osipenko , linux-arm-kernel Subject: Re: Re: [PATCH v7 10/24] drm/rockchip: dw_hdmi: Add support for hclk Message-ID: <20220309081810.GH405@pengutronix.de> References: <78207d97-b5a1-9792-8ec9-11fcf2e00370@gmail.com> <90c61299-f02c-607b-4734-7134852ef0a6@arm.com> <20220225131154.GE19585@pengutronix.de> <20220228141921.GN19585@pengutronix.de> <5184ecf2-8734-3121-cbbc-5dcfcf0d02f8@arm.com> <20220302112528.GV19585@pengutronix.de> <20220304142235.GL22780@pengutronix.de> <9ea0134e-aac7-60e1-5c58-ae31b4e1c422@collabora.com> <035f2dfd-bf35-abca-32bf-2be85cc88f8a@rock-chips.com> <20220309094139198367142@rock-chips.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220309094139198367142@rock-chips.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 08:57:51 up 88 days, 16:43, 82 users, load average: 0.00, 0.03, 0.08 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220309_001837_661403_CC66D428 X-CRM114-Status: GOOD ( 31.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org SGkgRWxhaW5lLAoKT24gV2VkLCBNYXIgMDksIDIwMjIgYXQgMDk6NDE6MzlBTSArMDgwMCwgemhh bmdxaW5nQHJvY2stY2hpcHMuY29tIHdyb3RlOgo+ICAgIGhp77yMYWxs77yaCj4gICAgTGV0IG1l IGV4cGxhaW4gdGhlIGNsb2NrIGRlcGVuZGVuY3nvvJoKPiAgICBGcm9tIHRoZSBjbG9jayB0cmVl LCBwY2xrX3ZvMCBhbmQgaGNsa192bzAgYXJlIGNvbXBsZXRlbHkgaW5kZXBlbmRlbnQKPiAgICBj bG9ja3Mgd2l0aCBkaWZmZXJlbnQgcGFyZW50IGNsb2NrcyBhbmQgZGlmZmVyZW50IGNsb2NrIGZy ZXF1ZW5jaWVz44CCCj4gICAgQnV0IHRoZSBuaXXCoHBhdGjCoGlzIDoKPiAgICBwY2xrX3ZvIGlz IGRlcGVuZGVudCBvbiBoY2xrX3ZvLCBhbmQgdGhlIHBjbGtfdm8gbml1IGdvZXMgdGhyb3VnaMKg IGhjbGtfdm8KPiAgICBuaXUuCgpUaGFua3MsIHRoaXMgaXMgdGhlIGluZm9ybWF0aW9uIHdlIGFy ZSBsb29raW5nIGZvci4gV2hhdCBpcyAiTklVIiBidHc/CkkgdGhpbmsgdGhpcyBpcyBldmVuIGRv Y3VtZW50ZWQgaW4gdGhlIFJlZmVyZW5jZSBNYW51YWwuIFdpdGggdGhlIHJpZ2h0CnBvaW50ZXIg SSBqdXN0IGZvdW5kOgoKPiBBIHBhcnQgb2Ygbml1IGNsb2NrcyBoYXZlIGEgZGVwZW5kZW5jZSBv biBhbm90aGVyIG5pdSBjbG9jayBpbiBvcmRlciB0bwo+IHNoYXJpbmcgdGhlIGludGVybmFsIGJ1 cy4gV2hlbiB0aGVzZSBjbG9ja3MgYXJlIGluIHVzZSwgYW5vdGhlciBuaXUKPiBjbG9jayBtdXN0 IGJlIG9wZW5lZCwgYW5kIGNhbm5vdCBiZSBnYXRlZC4gIFRoZXNlIGNsb2NrcyBhbmQgdGhlIHNw ZWNpYWwKPiBjbG9jayBvbiB3aGljaCB0aGV5IGFyZSByZWxpZWQgYXJlIGFzIGZvbGxvd2luZzoK Pgo+IENsb2NrcyB3aGljaCBoYXZlIGRlcGVuZGVuY3kgICAgIFRoZSBjbG9jayB3aGljaCBjYW4g bm90IGJlIGdhdGVkCj4gLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0KPiAuLi4KPiBwY2xrX3ZvX25pdSwgaGNsa192b19zX25p dSAgICAgICBoY2xrX3ZvX25pdQo+IC4uLgoKCgo+ICAgIFRoZSBjbG9jayB0cmVlIGFuZCBOSVUg YnVzIHBhdGhzIGFyZSBkZXNpZ25lZCBpbmRlcGVuZGVudGx5Cj4gICAgU28gdGhlcmUgYXJlIHRo cmVlIHNvbHV0aW9ucyB0byB0aGlzIHByb2JsZW06Cj4gICAgMS4gRFRTIGFkZHMgYSByZWZlcmVu Y2UgdG8gSGNsayB3aGlsZSByZWZlcmVuY2luZyBQY2xrLgo+ICAgIDIsIFRoZSBkZXBlbmRlbnQg Y2xvY2sgaXMgYWx3YXlzIG9uLCBzdWNoIGFzIEhDTEtfVk8wLMKgYnV0IHRoaXMgaXMgbm90Cj4g ICAgZnJpZW5kbHkgZm9yIHRoZSBzeXN0ZW0gcG93ZXIuCj4gICAgMy4gQ3JlYXRlIGEgbm9uLWNs b2NrLXRyZWUgcmVmZXJlbmNlLsKgQ2xrLWxpbmssIGZvciBleGFtcGxlLCB3ZSBoYXZlIGFuCj4g ICAgaW1wbGVtZW50YXRpb24gaW4gb3VyIGludGVybmFsIGJyYW5jaCwgYnV0IFVwc3RyZWFtIGlz IG5vdCBzdXJlIGhvdyB0bwo+ICAgIHB1c2ggaXQuCgpJIHRob3VnaHQgYWJvdXQgc29tZXRoaW5n IHNpbWlsYXIuIFRoYXQgd291bGQgaGVscCB1cyBoZXJlIGFuZCBvbiBpLk1YCndlIGhhdmUgYSBz aW1pbGFyIHNpdHVhdGlvbjogV2UgaGF2ZSBvbmUgYml0IHRoYXQgc3dpdGNoZXMgbXVsdGlwbGUK Y2xvY2tzLiBUaGF0IGFzIHdlbGwgY2Fubm90IGJlIGRlc2lnbmVkIHByb3Blcmx5IGluIHRoZSBj bG9jayBmcmFtZXdvcmsKY3VycmVudGx5LCBidXQgY291bGQgYmUgbW9kZWxsZWQgd2l0aCBhIGNv bmNlcHQgb2YgbGlua2VkIGNsb2Nrcy4KCkRvaW5nIHRoaXMgc291bmRzIGxpa2UgcXVpdGUgYSBi aXQgb2Ygd29yayBhbmQgZGlzY3Vzc2lvbiB0aG91Z2gsIEkKZG9uJ3QgcmVhbGx5IGxpa2UgaGF2 aW5nIHRoaXMgYXMgYSBkZXBlbmRlbmN5IHRvIG1haW5saW5lIHRoZSBWT1AyCmRyaXZlci4gSSB2 b3RlIGZvciAxLiBpbiB0aGF0IGNhc2UsIHdlIGNvdWxkIHN0aWxsIGlnbm9yZSB0aGUgaGNsayBp bgpkdHMgbGF0ZXIgd2hlbiB3ZSBoYXZlIGxpbmtlZCBjbG9ja3MuCgpTYXNjaGEKCi0tIApQZW5n dXRyb25peCBlLksuICAgICAgICAgICAgICAgICAgICAgICAgICAgfCAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgfApTdGV1ZXJ3YWxkZXIgU3RyLiAyMSAgICAgICAgICAgICAgICAgICAgICAg fCBodHRwOi8vd3d3LnBlbmd1dHJvbml4LmRlLyAgfAozMTEzNyBIaWxkZXNoZWltLCBHZXJtYW55 ICAgICAgICAgICAgICAgICAgfCBQaG9uZTogKzQ5LTUxMjEtMjA2OTE3LTAgICAgfApBbXRzZ2Vy aWNodCBIaWxkZXNoZWltLCBIUkEgMjY4NiAgICAgICAgICAgfCBGYXg6ICAgKzQ5LTUxMjEtMjA2 OTE3LTU1NTUgfAoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5p bmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8v bGludXgtYXJtLWtlcm5lbAo=