From patchwork Sat Jun 17 13:10:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Oltmanns X-Patchwork-Id: 13283593 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 337FDEB64DA for ; Sat, 17 Jun 2023 13:11:29 +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:MIME-Version:Message-ID:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=W2fXYPM7siM4TEi676XyIoJKT1lJfWplkjkp2oi4An0=; b=ssUTKWYEqMqo4a PWkf4Q19QschuKbm6RnKLI2nJlA786WQOnrIh/sJ7EXvzEHtIFCeBHbMVLsXFJKF6KZm39jFPcUWp N1H/EJzX53lxSJPSRIxNSIorfTB3swT0dhERjMgW+MOh5vTgbPsMsZTg3LLtiiO/Pbrq5qiuhEakZ BtwEw6tIHyiHbSFenDZAqbMZ5ayv4nqYq+yuS+ylQC7YU8A/16LHncwJmP1NDH6TRZ2YZDjUrCDLx Ce1GM2OxwDcES9miP55Btlvuko0sioGIrJII9LYch3vH1qLkXNbWjEATlZkUjok2MC2y2HWFPruqT DgrqNsrWvu4WoYEZJhYg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qAVhs-003e2e-2t; Sat, 17 Jun 2023 13:11:08 +0000 Received: from mout-p-202.mailbox.org ([80.241.56.172]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qAVhm-003e1X-1W for linux-arm-kernel@lists.infradead.org; Sat, 17 Jun 2023 13:11:07 +0000 Received: from smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-202.mailbox.org (Postfix) with ESMTPS id 4QjxH40VN0z9sTL; Sat, 17 Jun 2023 15:10:56 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oltmanns.dev; s=MBO0001; t=1687007456; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=zWr8+hmYK9XR2zX5ZGQSRHnHAbE1gsOnsSQTQWrON+s=; b=N4pbsOyqfAtDGzK6fEw/iUFKAfeYIVYHe5a2yp/ABkopdXkThidwX7010bmtQSGC+hAkgh xJq9YX82UrR6XtYSSBGKQwMfxWSMgq/TgOmSwHK927W64QPLNCcqi5bQ3O1pknnTOgVfr1 G+yotgs0SByLxLLdRURbXzL06vPrzBobUUO3pdw0kL4VH3VmvZuDQviRKxr102Yr25Iy9N tGO8geR+D1ma1stbsvQfMe8V0pVnaFQVm2SKSXuTjNXrrGCGn45NU6Wz2NHdNc7qaa+ZkV SL1gguMjt4Y755lKwACloB3mtaz8OuFtQq0A8AIlmQ1ykveMat0Qu+weUBdpvw== From: Frank Oltmanns To: Michael Turquette , Stephen Boyd Cc: Frank Oltmanns , "A.s. Dong" , Abel Vesa , Fabio Estevam , linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, NXP Linux Team , Peng Fan , Pengutronix Kernel Team , Sascha Hauer , Shawn Guo , Elaine Zhang Subject: [PATCH v5 0/2] clk: fractional-divider: Improve approximation when zero based and export Date: Sat, 17 Jun 2023 15:10:39 +0200 Message-ID: <20230617131041.18313-1-frank@oltmanns.dev> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230617_061102_705230_BD40F261 X-CRM114-Status: GOOD ( 11.23 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The fractional divider approximation does not utilize the full available range for clocks that are flagged CLK_FRAC_DIVIDER_ZERO_BASED. This patchset aims to fix that. It also adds test cases for the edge cases of fractional divider clocks with and without the CLK_FRAC_DIVIDER_ZERO_BASED flag to highlight the changes. Finally, it also exports clk_fractional_divider_general_approximation so that the test cases (but also other users like rockchip clk driver) can be compiled as a module. Unfortunately, I have no boards to test this patch. So all we have are the unit tests. It seems the only user of this flag in mainline is drivers/clk/imx/clk-composite-7ulp.c, therefore I'm cc-ing get_maintainers.pl --git-blame -f drivers/clk/imx/clk-composite-7ulp.c in the hopes of a wider audience. Thank you for considering this contribution, Frank P.S.: V4 was short-lived, because it triggered a compiler warning on clang. I'm sorry for the noise. -- Frank V4: https://lore.kernel.org/all/20230617102919.27564-1-frank@oltmanns.dev/ V3: https://lore.kernel.org/all/20230614185521.477924-1-frank@oltmanns.dev/ V2: https://lore.kernel.org/lkml/20230613083626.227476-1-frank@oltmanns.dev/ V1: https://lore.kernel.org/lkml/20230529133433.56215-1-frank@oltmanns.dev/ Changes in V5 (since V4): - Fix compiler warnings on clang by removing superfluous variable max_m in the test cases for the maximum denominator (n) and max_n in the test cases for max numerator (m). Thank you, Intel, for your kernel test robot! Changes in V4 (since V3): - Export clk_fractional_divider_general_approximation so that users (e.g., the testcases) can be compiled as modules. - Change test cases so that they test clk_fractional_divider_general_approximation again (like in V2) instead of clk_fd_round_rate (like in V3), but keeping the structure of V3 with separate file and individual test cases for each edge case. Changes in V3 (since V2): - Completely reworked the test cases - Moved tests to separate file as per Stephen's request - Move each edge case into their individual test case as per Stephen's request - Test clk_fd_round_rate instead of clk_fractional_divider_general_approximation as testing the latter broke builds Changes in V2 (since V1): - Added test case as requested by Stephen Boyd - Fixed commit message as the Cc: was missing a closing bracket, so that the original mail unfortunately did not go out to A. s. Dong. Frank Oltmanns (2): clk: fractional-divider: Improve approximation when zero based and export clk: fractional-divider: tests: Add test suite for edge cases drivers/clk/.kunitconfig | 1 + drivers/clk/Kconfig | 7 + drivers/clk/Makefile | 1 + drivers/clk/clk-fractional-divider.c | 27 +++- drivers/clk/clk-fractional-divider_test.c | 157 ++++++++++++++++++++++ 5 files changed, 186 insertions(+), 7 deletions(-) create mode 100644 drivers/clk/clk-fractional-divider_test.c