From mboxrd@z Thu Jan 1 00:00:00 1970 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 596ADECAAA1 for ; Mon, 19 Sep 2022 22:30:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229935AbiISWaz (ORCPT ); Mon, 19 Sep 2022 18:30:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229924AbiISWar (ORCPT ); Mon, 19 Sep 2022 18:30:47 -0400 Received: from mail-wm1-x333.google.com (mail-wm1-x333.google.com [IPv6:2a00:1450:4864:20::333]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63ED74F694 for ; Mon, 19 Sep 2022 15:30:44 -0700 (PDT) Received: by mail-wm1-x333.google.com with SMTP id o20-20020a05600c4fd400b003b4a516c479so410402wmq.1 for ; Mon, 19 Sep 2022 15:30:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date; bh=H64L7pxloe6ABjQPB6dOZxxjzAKfBLX2WzxDmXIAW9k=; b=h6hdPIuuXe/NvoMHtntpj69O9G+CzBzEIubkbH2eD3iogfL2/4jClFnCSNBob1GlbG 1BLs4fDDqrW6KF18dFxr15CuEee6qnNOoO8z6rvHWf5e+1W2nHhYvZ/ka8AI+GfSK9hC QLmfZtPIogBXCS7MLwijj2Qq5LU9CmllsqYXIliveBUKwMisqFS83sCEm6yjvk2vZnI2 d+BH9ApZUt04jn/7AVMFz38gfRupRSDRDuXuqxvX5HYFkSy/p/i5Zqqe6E6LpJeuxAA8 HCHK5ae9CptsbVx/vTnWBPL1bQoxPDnSk6bjkXGYMrsHyOYRRLDgpaFw8kKhVPAOhUC3 YR/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date; bh=H64L7pxloe6ABjQPB6dOZxxjzAKfBLX2WzxDmXIAW9k=; b=Y4vQ6R7LoBbohnjBW9QY5WI7DRrWzI9HHbI7GwvOGWb8izY5qTTnfQbwnwLTQCzjr6 ghOGO+E0EYMnXDHRi2dqt7VP9tBqvkQIUFIGhuyA5GgCGpXjQrn7wCoJKrf9/GlP9J67 Rx2mfra3TIKkak6TggET71pb7JwNE0ZwkDChq2lh/M+40M5Ztz+2NKpKhwO+deSWjwIz Tu/ufeCtmF6gqvJtSatQkhIYtDmWR+9l5pqkPdVMpDr9tN83hmVU7TozuEN7Me5NAvyB LYoHs1eUSaAvB4AE6vxlY/CTHGz6+TJBm4X3t3JqHJe0NTyI7AzKsq4JGS/BAIFe7xFP w3Ew== X-Gm-Message-State: ACrzQf0Zulj+t0Zh+eSXffOQIrKW7YLkHFXuag1DFbgofDxE2lOOD6iv IqOfZgibZxxe+nx80H4ujk5nfw== X-Google-Smtp-Source: AMsMyM4rhC/gFJIckxCkKzWYA+1S2wvnQLDFWaaAHKzLCWW53xSA/CpQVaBpxQp/saH/1X3R3XoI+g== X-Received: by 2002:a05:600c:27d1:b0:3b4:5e9c:23ed with SMTP id l17-20020a05600c27d100b003b45e9c23edmr237361wmb.180.1663626642884; Mon, 19 Sep 2022 15:30:42 -0700 (PDT) Received: from [192.168.0.17] (cpc152649-stkp13-2-0-cust121.10-2.cable.virginm.net. [86.15.83.122]) by smtp.gmail.com with ESMTPSA id l16-20020a05600c1d1000b003a601a1c2f7sm16407376wms.19.2022.09.19.15.30.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Sep 2022 15:30:42 -0700 (PDT) Message-ID: <193bf7d7-ac7c-5bcd-1f2b-f95dc3621f61@sifive.com> Date: Mon, 19 Sep 2022 23:30:41 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [RFC v4 08/10] pwm: dwc: add of/platform support Content-Language: en-GB To: =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Lee Jones , Thierry Reding , Krzysztof Kozlowski , Greentime Hu , jarkko.nikula@linux.intel.com, William Salmon , Jude Onyenegecha References: <20220816211454.237751-1-ben.dooks@sifive.com> <20220816211454.237751-9-ben.dooks@sifive.com> <20220914164720.bjh6tqw6zb66vsyz@pengutronix.de> From: Ben Dooks In-Reply-To: <20220914164720.bjh6tqw6zb66vsyz@pengutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/09/2022 17:47, Uwe Kleine-König wrote: > On Tue, Aug 16, 2022 at 10:14:52PM +0100, Ben Dooks wrote: >> The dwc pwm controller can be used in non-PCI systems, so allow >> either platform or OF based probing. >> >> Signed-off-by: Ben Dooks >> --- >> v4: >> - split the of code out of the core >> - moved the compile test code earlier >> - fixed review comments >> - used NS_PER_SEC >> - use devm_clk_get_enabled >> v3: >> - changed compatible name >> --- >> drivers/pwm/Kconfig | 9 +++++ >> drivers/pwm/Makefile | 1 + >> drivers/pwm/pwm-dwc-of.c | 78 ++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 88 insertions(+) >> create mode 100644 drivers/pwm/pwm-dwc-of.c >> >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig >> index a9f1c554db2b..f1735653365f 100644 >> --- a/drivers/pwm/Kconfig >> +++ b/drivers/pwm/Kconfig >> @@ -192,6 +192,15 @@ config PWM_DWC_PCI >> To compile this driver as a module, choose M here: the module >> will be called pwm-dwc-pci. >> >> +config PWM_DWC_OF >> + tristate "DesignWare PWM Controller (OF bus) >> + depends on PWM_DWC && OF >> + help >> + PWM driver for Synopsys DWC PWM Controller on an OF bus. >> + >> + To compile this driver as a module, choose M here: the module >> + will be called pwm-dwc-of. >> + >> config PWM_EP93XX >> tristate "Cirrus Logic EP93xx PWM support" >> depends on ARCH_EP93XX || COMPILE_TEST >> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile >> index a70d36623129..d1fd1641f077 100644 >> --- a/drivers/pwm/Makefile >> +++ b/drivers/pwm/Makefile >> @@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o >> obj-$(CONFIG_PWM_CRC) += pwm-crc.o >> obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o >> obj-$(CONFIG_PWM_DWC) += pwm-dwc.o >> +obj-$(CONFIG_PWM_DWC_OF) += pwm-dwc-of.o >> obj-$(CONFIG_PWM_DWC_PCI) += pwm-dwc-pci.o >> obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o >> obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o >> diff --git a/drivers/pwm/pwm-dwc-of.c b/drivers/pwm/pwm-dwc-of.c >> new file mode 100644 >> index 000000000000..d18fac287325 >> --- /dev/null >> +++ b/drivers/pwm/pwm-dwc-of.c >> @@ -0,0 +1,78 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * DesignWare PWM Controller driver OF >> + * >> + * Copyright (C) 2022 SiFive, Inc. >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#include "pwm-dwc.h" >> + >> +static int dwc_pwm_plat_probe(struct platform_device *pdev) >> +{ >> + struct device *dev = &pdev->dev; >> + struct dwc_pwm *dwc; >> + int ret; >> + >> + dwc = dwc_pwm_alloc(dev); >> + if (!dwc) >> + return -ENOMEM; >> + >> + dwc->base = devm_platform_ioremap_resource(pdev, 0); >> + if (IS_ERR(dwc->base)) >> + return dev_err_probe(dev, PTR_ERR(dwc->base), >> + "failed to map IO\n"); > > devm_platform_ioremap_resource() already emits an error message. ok, fixed >> + >> + dwc->clk = devm_clk_get_enabled(dev, "timer"); >> + if (IS_ERR(dwc->clk)) >> + return dev_err_probe(dev, PTR_ERR(dwc->clk), >> + "failed to get timer clock\n"); >> + >> + clk_prepare_enable(dwc->clk); > > You don't need clk_prepare_enable() as you used devm_clk_get_enabled(). > > (Otherwise, when keeping clk_prepare_enable() you need to check the > return value.) ok, fixed. I didn't notice that when changing to devm_ > >> + dwc->clk_ns = NSEC_PER_SEC / clk_get_rate(dwc->clk); > > I think I already pointed out this is non-optimal. > > Later you use clk_ns in __dwc_pwm_configure_timer(): > > tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, dwc->clk_ns); > > So what you really want here is: > > tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * clk_get_rate(dwc->clk), NSEC_PER_SEC); > > With for example clk_get_rate(dwc->clk) = 201171875 and duty_cycle = > 4096 you now get clk_ns = 4 (while the exact value is 4.97087..), tmp = > 1024, while the exact value is 824. > > So the idea is to add a clkrate member to the private driver struct, let > it default to 100000000 for the pci case and use the line I suggested > above. ok, will consider keeping the rate in hz and modifiying the pci version to use 10 * NSEC_PER_SEC for the rate. I've been trying to avoid changing the pci case, but I think for anything with a clk pointer we should be doing clk_get_rate in the calc code > >> + >> + ret = devm_pwmchip_add(dev, &dwc->chip); >> + if (ret) >> + return ret; >> + >> + return 0; > > This is equivalent to > > return ret; Will sort that out. >> +} >> + >> +static int dwc_pwm_plat_remove(struct platform_device *pdev) >> +{ >> + struct dwc_pwm *dwc = platform_get_drvdata(pdev); >> + >> + clk_disable_unprepare(dwc->clk); >> + return 0; >> +} > > When dropping clk_prepare_enable() the .remove callback can go away, > too. thanks, spotted that one a while ago. >> + >> +static const struct of_device_id dwc_pwm_dt_ids[] = { >> + { .compatible = "snps,dw-apb-timers-pwm2" }, >> + { }, >> +}; >> +MODULE_DEVICE_TABLE(of, dwc_pwm_dt_ids); >> + >> +static struct platform_driver dwc_pwm_plat_driver = { >> + .driver = { >> + .name = "dwc-pwm", >> + .of_match_table = dwc_pwm_dt_ids, >> + }, >> + .probe = dwc_pwm_plat_probe, >> + .remove = dwc_pwm_plat_remove, >> +}; >> + >> +module_platform_driver(dwc_pwm_plat_driver); >> + >> +MODULE_ALIAS("platform:dwc-pwm-of"); >> +MODULE_AUTHOR("Ben Dooks "); >> +MODULE_DESCRIPTION("DesignWare PWM Controller"); >> +MODULE_LICENSE("GPL"); > > Best regards > Uwe >