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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40592C282C0 for ; Fri, 25 Jan 2019 03:48:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1022B21855 for ; Fri, 25 Jan 2019 03:48:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728841AbfAYDsu (ORCPT ); Thu, 24 Jan 2019 22:48:50 -0500 Received: from Mailgw01.mediatek.com ([1.203.163.78]:33533 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726304AbfAYDsu (ORCPT ); Thu, 24 Jan 2019 22:48:50 -0500 X-UUID: 2f451d7b0e6c428d82be0b570207cc9c-20190125 X-UUID: 2f451d7b0e6c428d82be0b570207cc9c-20190125 Received: from mtkcas36.mediatek.inc [(172.27.4.250)] by mailgw01.mediatek.com (envelope-from ) (mailgw01.mediatek.com ESMTP with TLS) with ESMTP id 657249204; Fri, 25 Jan 2019 11:48:37 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by MTKMBS31DR.mediatek.inc (172.27.6.102) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 25 Jan 2019 11:48:35 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 25 Jan 2019 11:48:36 +0800 Message-ID: <1548388116.29237.15.camel@mtkswgap22> Subject: Re: [PATCH v1 1/5] pwm: mediatek: add a property "mediatek,num-pwms" From: Ryder Lee To: Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , John Crispin CC: "linux-pwm@vger.kernel.org" , "devicetree@vger.kernel.org" , Sean Wang , Weijie Gao =?UTF-8?Q?=28=E9=AB=98=E6=83=9F=E6=9D=B0=29?= , "linux-kernel@vger.kernel.org" , "Thierry Reding" , "linux-mediatek@lists.infradead.org" , Matthias Brugger , "linux-arm-kernel@lists.infradead.org" Date: Fri, 25 Jan 2019 11:48:36 +0800 In-Reply-To: <20190121084948.frpcgg6wkdjxkl7k@pengutronix.de> References: <1547866487.14213.10.camel@mtkswgap22> <20190121084948.frpcgg6wkdjxkl7k@pengutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +John HI John, On Mon, 2019-01-21 at 16:49 +0800, Uwe Kleine-König wrote: > On Sat, Jan 19, 2019 at 10:54:47AM +0800, Ryder Lee wrote: > > On Fri, 2019-01-18 at 09:43 +0100, Matthias Brugger wrote: > > > > > > On 18/01/2019 04:24, Ryder Lee wrote: > > > > This adds a property "mediatek,num-pwms" to avoid having an endless > > > > list of compatibles with no differences for the same driver. > > > > > > > > Thus, the driver should have backwards compatibility to older DTs. > > > > > > > > Signed-off-by: Ryder Lee > > > > --- > > > > Changes since v1: add some checks for backwards compatibility. > > > > --- > > > > drivers/pwm/pwm-mediatek.c | 27 ++++++++++++++++++--------- > > > > 1 file changed, 18 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c > > > > index eb6674c..81b7e5e 100644 > > > > --- a/drivers/pwm/pwm-mediatek.c > > > > +++ b/drivers/pwm/pwm-mediatek.c > > > > @@ -55,7 +55,7 @@ enum { > > > > }; > > > > > > > > struct mtk_pwm_platform_data { > > > > - unsigned int num_pwms; > > > > + unsigned int num_pwms; /* it should not be used in the future SoCs */ > > > > bool pwm45_fixup; > > > > bool has_clks; > > > > }; > > > > @@ -226,27 +226,36 @@ static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > > > > > > > > static int mtk_pwm_probe(struct platform_device *pdev) > > > > { > > > > - const struct mtk_pwm_platform_data *data; > > > > + struct device_node *np = pdev->dev.of_node; > > > > struct mtk_pwm_chip *pc; > > > > struct resource *res; > > > > - unsigned int i; > > > > + unsigned int i, num_pwms; > > > > int ret; > > > > > > > > pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL); > > > > if (!pc) > > > > return -ENOMEM; > > > > > > > > - data = of_device_get_match_data(&pdev->dev); > > > > - if (data == NULL) > > > > - return -EINVAL; > > > > - pc->soc = data; > > > > + pc->soc = of_device_get_match_data(&pdev->dev); > > > > > > > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > > > pc->regs = devm_ioremap_resource(&pdev->dev, res); > > > > if (IS_ERR(pc->regs)) > > > > return PTR_ERR(pc->regs); > > > > > > > > - for (i = 0; i < data->num_pwms + 2 && pc->soc->has_clks; i++) { > > > > + /* Check if we have set 'num-pwms' in DTs. */ > > > > + ret = of_property_read_u32(np, "mediatek,num-pwms", &num_pwms); > > > > + if (ret < 0) { > > > > + /* If no, fallback to use SoC data for backwards compatibility. */ > > > > + if (pc->soc->num_pwms) { > > > > + num_pwms = pc->soc->num_pwms; > > > > > > Maybe that's bike shedding, but I think it would be better to carve out the > > > num_pwms from the mtk_pwm_platform_data and check against the compatible here. > > > > I'm not sure how to properly curve it out? I think we still need this > > variable to save the specific value for some legacy SoCs (with older > > DTs). > > I guess he means something like: > > if (is_compatible_to_variant_A(dev)) > num_pwms = 12; > else if (is_compatible_to_variant_B(dev)) > num_pwms = 2; > > . In my eyes the bike shed should be light red and I prefer to collect > the fallback num_pwms in the compatible_data as is to keep the code > simpler. Maybe rename the member from num_pwms to fallback_num_pwms to > make it more obvious that it doesn't represent the actually used value. > > > > With a expressive comment it will help other driver developers to not start > > > adding num_pwms in the platform data in their first attempt. > > > > Definitely. > > My suggestion was to add a dev_warn, which IMHO is still better than a > comment. > > Best regards > Uwe > Unrelated to this patch: I'm ready to send v2 to allocate the clks array dynamically, but I guess MT7628 couldn't work in original code. In mtk_pwm_config(): clk = pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]; .... resolution = (u64)NSEC_PER_SEC * 1000; do_div(resolution, clk_get_rate(clk)); .... I think clk should be NULL and resolution is always 0 here. Ryder