From patchwork Fri Feb 23 17:18:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Xiwen via B4 Relay X-Patchwork-Id: 13569618 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E1961272D8; Fri, 23 Feb 2024 17:18:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708708734; cv=none; b=dPO1rSBLIbRQOyvu5zwTIQkiOtW57uJ0oBWaBX3hNXiBFVvgTJwJ8s2Xg8xL1LtPQFwGX+RzMzqXjG5nczkdk4BBjP3BhT+ldIZrDAGn+bQaNHd9ciiVXoUGPnsZj/beaWE2/FyqobWiNtPNnQtCVMm3OkUhn4GvrOZ79ona3vs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708708734; c=relaxed/simple; bh=jPhUX7fseszIBa5Cz4g6HtJ32wY5HpFdNrxQegeyAcU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=dFmsDUeyNEoVTc19/r/SidKfDQTtreNccp0L2lZoQbS37N/TsstN2lIHmVnSSOTmctnLWcO2z47ZllSorUb5vG8MmFowugSdswERQJeL+IOcpfDN1i4Qqo9C6B90WDC538xY4RLjkqHMxo83QC6uifw9qdwWt76WdOHgJT3YWxM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XF5+3niz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XF5+3niz" Received: by smtp.kernel.org (Postfix) with ESMTPS id 8925FC433C7; Fri, 23 Feb 2024 17:18:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708708733; bh=jPhUX7fseszIBa5Cz4g6HtJ32wY5HpFdNrxQegeyAcU=; h=From:Date:Subject:To:Cc:Reply-To:From; b=XF5+3niz1AvIp05ztwt2NQuB8gytrjZBE9VbVU8Ge59jvkl6U8I3PaXf0sVbfcngD xJ4HlxqQYpl8bI4RG/SlwpYKhMmwreT7RUEkLphSee8uogcE0N80IBCGPRalXX38+E cU9kANXDxFRDDMGmUmk5BMcu/dKC4FpINudh3wpOcsPKq30XS3TE30gaOSyFZ/rqdh oY4807xtUmjPO6MKY7q4AEVze03XjL0sDRE49QHiHyNxXNW7qqDwnvzNslgF++1CsF jtZqeMPuVrLO8L3m3SlGOt39gPrvZ80/59fajymbUOVLITGYsS/Q5KZrDF3gsDtje3 WWOE0egbf/Jsw== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75F77C5478C; Fri, 23 Feb 2024 17:18:53 +0000 (UTC) From: Yang Xiwen via B4 Relay Date: Sat, 24 Feb 2024 01:18:52 +0800 Subject: [PATCH RESEND] clk: set initial best mux parent to current parent when determining rate Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240224-mux-v1-1-608cc704ef43@outlook.com> To: Michael Turquette , Stephen Boyd Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, Yang Xiwen X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1708708732; l=1451; i=forbidden405@outlook.com; s=20230724; h=from:subject:message-id; bh=fggch9mxMQ8SzPlFXnQcVvzDJCD3ro+vLZXoDYu1RGE=; b=WdFzW2xYhaZML01H7Wn3y7hOtv/t49Ffr8hwuamJTDM1SyPptIImRnP9E/eEQE/s1XsHe1wfJ I2CNZM08YmmCIAk+hVTmfKzxwd98Rl8RXD3aRxo0wP4bLDZ+v0hboHu X-Developer-Key: i=forbidden405@outlook.com; a=ed25519; pk=qOD5jhp891/Xzc+H/PZ8LWVSWE3O/XCQnAg+5vdU2IU= X-Endpoint-Received: by B4 Relay for forbidden405@outlook.com/20230724 with auth_id=67 X-Original-From: Yang Xiwen Reply-To: From: Yang Xiwen Originally, the initial clock rate is hardcoded to 0, this can lead to some problem when setting a very small rate with CLK_MUX_ROUND_NEAREST. For example, if the lowest possible rate privided by the mux is 1000Hz, setting a rate below 500Hz will fail, because no clock can provide a better rate than the non-existant 0. But it should succeed with 1000Hz being set. Setting the initial best parent to current parent could solve this bug very well. Signed-off-by: Yang Xiwen --- This is actually a v2 of [1], but seems too simple to have a unittest. It's tested in a mmc host driver. [1]: https://lore.kernel.org/linux-clk/20230421-clk-v3-1-9ff79e7e7fed@outlook.com/ --- drivers/clk/clk.c | 4 ++++ 1 file changed, 4 insertions(+) --- base-commit: 8d3dea210042f54b952b481838c1e7dfc4ec751d change-id: 20240215-mux-6db8b3714590 Best regards, diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 2253c154a824..d98cebd7ff03 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -649,6 +649,10 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw, /* find the parent that can provide the fastest rate <= rate */ num_parents = core->num_parents; + if (core->parent) { + best_parent = core->parent; + best = clk_core_get_rate_nolock(best_parent); + } for (i = 0; i < num_parents; i++) { unsigned long parent_rate;