From patchwork Mon Aug 7 08:47:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Felsch X-Patchwork-Id: 13343190 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 78D6AEB64DD for ; Mon, 7 Aug 2023 08:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229703AbjHGIsB (ORCPT ); Mon, 7 Aug 2023 04:48:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229512AbjHGIsB (ORCPT ); Mon, 7 Aug 2023 04:48:01 -0400 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 4F0621722 for ; Mon, 7 Aug 2023 01:47:56 -0700 (PDT) Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1qSvu0-00036z-9w; Mon, 07 Aug 2023 10:47:48 +0200 From: Marco Felsch To: abelvesa@kernel.org, peng.fan@nxp.com, mturquette@baylibre.com, shawnguo@kernel.org, s.hauer@pengutronix.de, rasmus.villemoes@prevas.dk, adrian.alonso@nxp.com, aford173@gmail.com, a.fatoum@pengutronix.de Cc: linux-clk@vger.kernel.org, linux-imx@nxp.com, kernel@pengutronix.de Subject: [PATCH v2 2/2] clk: imx: pll14xx: dynamically configure PLL for 393216000/361267200Hz Date: Mon, 7 Aug 2023 10:47:44 +0200 Message-Id: <20230807084744.1184791-2-m.felsch@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230807084744.1184791-1-m.felsch@pengutronix.de> References: <20230807084744.1184791-1-m.felsch@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:1101:1d::28 X-SA-Exim-Mail-From: m.felsch@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-clk@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org From: Ahmad Fatoum Since commit b09c68dc57c9 ("clk: imx: pll14xx: Support dynamic rates"), the driver has the ability to dynamically compute PLL parameters to approximate the requested rates. This is not always used, because the logic is as follows: - Check if the target rate is hardcoded in the frequency table - Check if varying only kdiv is possible, so switch over is glitch free - Compute rate dynamically by iterating over pdiv range If we skip the frequency table for the 1443x PLL, we find that the computed values differ to the hardcoded ones. This can be valid if the hardcoded values guarantee for example an earlier lock-in or if the divisors are chosen, so that other important rates are more likely to be reached glitch-free. For rates (393216000 and 361267200, this doesn't seem to be the case: They are only approximated by existing parameters (393215995 and 361267196 Hz, respectively) and they aren't reachable glitch-free from other hardcoded frequencies. Dropping them from the table allows us to lock-in to these frequencies exactly. This is immediately noticeable because they are the assigned-clock-rates for IMX8MN_AUDIO_PLL1 and IMX8MN_AUDIO_PLL2, respectively and a look into clk_summary so far showed that they were a few Hz short of the target: imx8mn-board:~# grep audio_pll[12]_out /sys/kernel/debug/clk/clk_summary audio_pll2_out 0 0 0 361267196 0 0 50000 N audio_pll1_out 1 1 0 393215995 0 0 50000 Y and afterwards: imx8mn-board:~# grep audio_pll[12]_out /sys/kernel/debug/clk/clk_summary audio_pll2_out 0 0 0 361267200 0 0 50000 N audio_pll1_out 1 1 0 393216000 0 0 50000 Y This change is equivalent to adding following hardcoded values: /* rate mdiv pdiv sdiv kdiv */ PLL_1443X_RATE(393216000, 655, 5, 3, 23593), PLL_1443X_RATE(361267200, 497, 33, 0, -16882), Fixes: 053a4ffe2988 ("clk: imx: imx8mm: fix audio pll setting") Cc: stable@vger.kernel.org # v5.18+ Signed-off-by: Ahmad Fatoum Signed-off-by: Marco Felsch --- v2: - new patch drivers/clk/imx/clk-pll14xx.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c index dc6bc21dff41..0d58d85c375e 100644 --- a/drivers/clk/imx/clk-pll14xx.c +++ b/drivers/clk/imx/clk-pll14xx.c @@ -64,8 +64,6 @@ static const struct imx_pll14xx_rate_table imx_pll1443x_tbl[] = { PLL_1443X_RATE(650000000U, 325, 3, 2, 0), PLL_1443X_RATE(594000000U, 198, 2, 2, 0), PLL_1443X_RATE(519750000U, 173, 2, 2, 16384), - PLL_1443X_RATE(393216000U, 262, 2, 3, 9437), - PLL_1443X_RATE(361267200U, 361, 3, 3, 17511), }; struct imx_pll14xx_clk imx_1443x_pll = {