From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=103.126.93.3 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793062635; b=4oP57G/Io9OpCA136gEMS6sngg1zHAtZw64bckSXloHDwp096gi0JJLRtYDrQtPp0Idb B/MKNSdw/mXpNxbSG+tExwM3+jqG2ft1attaPOfKBf1RzyaMZ5YjO8AmQS7bfl/nNXdp8 M6XVOrR/JFV/2nYfSdPNOr0LkS3bQzqg1kWt65XDS+3kFsRSvrLh2VvC4RUwe3xPRYsqS bffBXmN/9d8R48AhR2UxkFReThO0bcwcKJ3eiGAYK8czcdE4qUlSQU2XsOQXNfmVHflLb oZ11TvEEeEJakzc1Poek6WFStZxkmhPPX5Djn3d7zPFb32k5Bd8UyRgervbYN8G8xlA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793062635; h=DMARC-Filter:Received:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:X-HM-Tid:X-HM-MType:X-HM-Spam-Status: DKIM-Signature; bh=LTWlkC3bqSlTG2YkDHxmrbiZeaSggK5ojxGD1nHsNsI=; b=fV6gu6AmjPRTl3WWKHTF6QfIwDNPuA4mkZwkCHguq1JSNh7q3k3+LVE9XfHNlK2YiHkS I6LLOquAPgTR1/LPgGO4nPXDDGnqq5p+6F/9lbxRNZbFwgBK9T3FuJ58aJNw0BEqibOlY tjol0z9fJW0+wEy2yrewXaJD7WLthEWvCl1aEhoXt394mIYwT+4tn09qppDjbJWqvidU6 V/yIrUprMmrcrXcLbu9R+aEuKqYdpc2vkEVMAkIGA9+xXyerY6VKudE0CTqZkh/WeQvZc fnmQWe1znP69pXpZUYUxz27Xuy84Nikiq/jiVpSS6GlUPc1Ix6lrDSwQQTw4JLeJieQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=rock-chips.com; spf=pass smtp.mailfrom=rock-chips.com; dkim=pass header.d=rock-chips.com header.i=@rock-chips.com header.a=rsa-sha256 header.s=default header.b=hV1UNJnX; arc=none smtp.remote-ip=103.126.93.3 Received: from mail-m933.xmail.ntesmail.com (mail-m933.xmail.ntesmail.com [103.126.93.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27D2C606A31A; Tue, 27 Oct 2026 00:57:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 27D2C606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=rock-chips.com header.i=@rock-chips.com header.a=rsa-sha256 header.s=default header.b=hV1UNJnX Received: from [172.16.12.93] (unknown [61.154.14.86]) by smtp.qiye.163.com (Hmail) with ESMTP id 526eb68c8; Tue, 27 Oct 2026 08:57:04 +0800 (GMT+08:00) Message-ID: <9f8114fc-c4bd-4f50-8c5a-a8afc94249b8@rock-chips.com> Date: Tue, 27 Oct 2026 08:57:02 +0800 X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/3] clk: rockchip: Add RK3572 clock and reset support To: Cunhao Lu <1579567540@qq.com>, Stephen Boyd , Brian Masney , Jerome Brunet , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Heiko Stuebner , Philipp Zabel , Richard Cochran Cc: linux-clk , devicetree , linux-arm-kernel , linux-rockchip , linux-kernel , netdev References: <20261026-add-board-ok3572-c-clk-v3-0-dbabfa39d692@qq.com> <20261026-add-board-ok3572-c-clk-v3-3-dbabfa39d692@qq.com> <0d5de6fd-3150-4898-a652-7f5b64dcaf07@rock-chips.com> From: =?UTF-8?B?5byg5pm0?= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-HM-Tid: 0aa17adc5aa409d2kunmf1cad9ec130d7c4 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlDQ0JJVkhLTU1JSB8dQ05LHlYVFA kWGhdVEwETFhoSFyQUDg9ZV1kYEgtZQVlNSlVKTk9VSk9VQ01ZV1kWGg8SFR0UWUFZT0tIVUJCSU 5LVUpLS1VKQktCWQY+ DKIM-Signature: a=rsa-sha256; b=hV1UNJnX6QxnjUOiSLVmQD2uma3cke/feZxFVH5S4idvDB+vzdGr/E9wgn464etOHYT4aZjOe+e90+ba5lq8wnXpsEnx+r0uShc0/GkpQM+Mdf57U1BSBg7TzTBAjAc4coCZPgYikVjqHNbeHLnvM30slTEgbXfdnZ7gyX4ZygI=; s=default; c=relaxed/relaxed; d=rock-chips.com; v=1; bh=LTWlkC3bqSlTG2YkDHxmrbiZeaSggK5ojxGD1nHsNsI=; h=date:mime-version:subject:message-id:from; 在 2026/10/26 22:56, Cunhao Lu 写道: > Hi zhangqing, > >> This is in clk.h, please submit it separately. > Thanks for the review. I will move COMPOSITE_MUXTBL to clk.h and add it > in a separate preparatory patch. > >> This is incorrect here; there should be no negative values. Two's >> complement is used here, so a conversion is needed. For example, >> -12955 should be 52581. >> >> In clk-pll.c, cur.k & BIT(15) is used to determine the two's complement >> conversion. > I agree that the hardware expects a 16-bit two's complement encoding: > -12955 is encoded as 0xcd65, which is 52581 when read as unsigned. The > difference here is how that coefficient is represented in the rate > table on the kernel version this series targets. > > I found the cur.k & BIT(15) branch in Rockchip's downstream develop-6.12 > tree. There, k is unsigned int, so the driver explicitly checks bit 15 > and subtracts the magnitude of a negative fractional coefficient. > > This series uses the upstream implementation. Both v2 and v3 are based > on a804c5742bff, which already contains commit > 581478883477 ("clk: rockchip: Fractional PLL coefficient on RK3588/RK3576 > is two's complement"). That commit changed the k member of > struct rockchip_pll_rate_table to: > > s16 k; /* fractional part, 16 bit two's complement */ > > On this base, rockchip_rk3588_pll_recalc_rate() uses signed arithmetic: > > s64 frac_rate64 = (s64)prate * cur.k; > postdiv = cur.p * 65536; > rate64 += div_s64(frac_rate64, postdiv); > > The signed type represents the negative coefficient directly, so this > implementation does not need a separate cur.k & BIT(15) branch. For > example, the mainline RK3576 rate table already contains: > > RK3588_PLL_RATE(955520000, 3, 478, 2, -15730), > RK3588_PLL_RATE(785560000, 3, 393, 2, -14419), > > These are exactly the same entries as in this RK3572 patch, including > p, m and s. Mainline RK3588 uses the same entries as well. Since RK3572 > uses this shared upstream PLL implementation, I will follow the > mainline RK3576 convention for its rate table. > > Writing 52581 directly into an s16 initializer would require an > out-of-range implicit conversion; a reduced compiler test reproduces > Clang's constant-conversion diagnostic. An explicit cast such as > (s16)52581 would produce the same signed coefficient, but would add a > conversion that the existing mainline tables avoid. Using -12955 > directly makes the value used in the rate calculation clear and stays > consistent with RK3576. > > The register encoding is preserved: the write path passes k through > HIWORD_UPDATE() with a 0xffff mask, so -12955 still writes 0xcd65 into > the coefficient field. The five initializer changes from v2 to v3 only > make the signed values explicit; they do not change p, m, s or the > 16-bit coefficient encodings. In particular, no further adjustment of > m is needed for these representation changes. > > I will therefore retain the signed coefficients, following mainline > RK3576. OK > > Best regards, > Cunhao