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: 13283597 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 31AADEB64D9 for ; Sat, 17 Jun 2023 13:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234911AbjFQNLD (ORCPT ); Sat, 17 Jun 2023 09:11:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231877AbjFQNLC (ORCPT ); Sat, 17 Jun 2023 09:11:02 -0400 Received: from mout-p-202.mailbox.org (mout-p-202.mailbox.org [IPv6:2001:67c:2050:0:465::202]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A711F3; Sat, 17 Jun 2023 06:11:00 -0700 (PDT) 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 Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.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