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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 2FD42C433DF for ; Thu, 30 Jul 2020 08:55:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11F7F2075F for ; Thu, 30 Jul 2020 08:55:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729241AbgG3IzP (ORCPT ); Thu, 30 Jul 2020 04:55:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729233AbgG3IzO (ORCPT ); Thu, 30 Jul 2020 04:55:14 -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 CE9CCC0619D2 for ; Thu, 30 Jul 2020 01:55:13 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k14L8-0002K4-FP; Thu, 30 Jul 2020 10:55:02 +0200 Received: from mfe by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1k14L2-0003Tl-Jy; Thu, 30 Jul 2020 10:54:56 +0200 Date: Thu, 30 Jul 2020 10:54:56 +0200 From: Marco Felsch To: Dmitry Torokhov Cc: Horia =?utf-8?Q?Geant=C4=83?= , Herbert Xu , "David S. Miller" , Rob Herring , Shawn Guo , =?iso-8859-1?Q?Andr=E9?= Draszik , Robin Gong , Anson Huang , Fabio Estevam , Aymen Sghaier , Adam Ford , linux-input@vger.kernel.org, linux-crypto@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, NXP Linux Team Subject: Re: [PATCH v3 2/3] Input: snvs_pwrkey - enable snvs clock as needed Message-ID: <20200730085456.qy3uen46nfhkxba4@pengutronix.de> References: <20200723074314.3304-1-horia.geanta@nxp.com> <20200723074314.3304-3-horia.geanta@nxp.com> <20200729073323.pse772mh44bzgdai@pengutronix.de> <20200730060426.GD1665100@dtor-ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200730060426.GD1665100@dtor-ws> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 10:02:52 up 257 days, 23:21, 250 users, load average: 0.24, 0.19, 0.09 User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-crypto@vger.kernel.org Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Hi Dmitry, On 20-07-29 23:04, Dmitry Torokhov wrote: > On Wed, Jul 29, 2020 at 09:33:23AM +0200, Marco Felsch wrote: > > Hi, > > > > On 20-07-23 10:43, Horia Geantă wrote: > > > From: André Draszik > > > > > > At the moment, enabling this driver without the SNVS RTC driver > > > being active will hang the kernel as soon as the power button > > > is pressed. > > > > > > The reason is that in that case the SNVS isn't enabled, and > > > any attempt to read the SNVS registers will simply hang forever. > > > > > > Ensure the clock is enabled (during the interrupt handler) to > > > make this driver work. > > > > > > Also see commit 7f8993995410 ("drivers/rtc/rtc-snvs: add clock support") > > > and commit edb190cb1734 > > > ("rtc: snvs: make sure clock is enabled for interrupt handle") > > > for similar updates to the snvs rtc driver. > > > > > > Signed-off-by: André Draszik > > > Reviewed-by: Horia Geantă > > > Signed-off-by: Horia Geantă > > > --- > > > drivers/input/keyboard/snvs_pwrkey.c | 28 +++++++++++++++++++++++++++- > > > 1 file changed, 27 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/input/keyboard/snvs_pwrkey.c b/drivers/input/keyboard/snvs_pwrkey.c > > > index 2f5e3ab5ed63..382d2ae82c9b 100644 > > > --- a/drivers/input/keyboard/snvs_pwrkey.c > > > +++ b/drivers/input/keyboard/snvs_pwrkey.c > > > @@ -16,6 +16,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > #include > > > #include > > > > > > @@ -38,6 +39,7 @@ struct pwrkey_drv_data { > > > int wakeup; > > > struct timer_list check_timer; > > > struct input_dev *input; > > > + struct clk *clk; > > > u8 minor_rev; > > > }; > > > > > > @@ -47,7 +49,10 @@ static void imx_imx_snvs_check_for_events(struct timer_list *t) > > > struct input_dev *input = pdata->input; > > > u32 state; > > > > > > + clk_enable(pdata->clk); > > > regmap_read(pdata->snvs, SNVS_HPSR_REG, &state); > > > + clk_disable(pdata->clk); > > > + > > > state = state & SNVS_HPSR_BTN ? 1 : 0; > > > > > > /* only report new event if status changed */ > > > @@ -74,11 +79,13 @@ static irqreturn_t imx_snvs_pwrkey_interrupt(int irq, void *dev_id) > > > > > > pm_wakeup_event(input->dev.parent, 0); > > > > > > + clk_enable(pdata->clk); > > > + > > > regmap_read(pdata->snvs, SNVS_LPSR_REG, &lp_status); > > > if (lp_status & SNVS_LPSR_SPO) { > > > if (pdata->minor_rev == 0) { > > > /* > > > - * The first generation i.MX6 SoCs only sends an > > > + * The first generation i.MX[6|7] SoCs only send an > > > * interrupt on button release. To mimic power-key > > > * usage, we'll prepend a press event. > > > */ > > > @@ -96,6 +103,8 @@ static irqreturn_t imx_snvs_pwrkey_interrupt(int irq, void *dev_id) > > > /* clear SPO status */ > > > regmap_write(pdata->snvs, SNVS_LPSR_REG, SNVS_LPSR_SPO); > > > > > > + clk_disable(pdata->clk); > > > > I'm not so happy about clk_enable/disable() during the interrupt > > routine since those routines should be handled fast. Since we assume > > that the clock is always oni > > We do? I thought that the fact that clock might be off is the root of > the problem. Currently yes else the driver would never work. I thought so at least after reading the commit message. But after checking the imx6qdl I found that the imx6qdl has no clock-gate for the SNVS module. I think Horia had Problems on a imx7 device since he adapted the comment to cover the imx7. Which makes more sense since the imx7 has a clock gate but the commit message is wrong. After checking the device-tree's in mainline all imx7 and imx8 devices specify the "snvs-pwrkey" clock so this is a new feature and they need the clock. So IMHO for those devices a clock should be required and not optional. > > I would rather call clk_prepare_enable() > > during probe() and keep the clock on. > > clk_enable() must not sleep and is supposed to be lightweight. This > interrupt I believe is supposed to be infrequent, so having it here > should be fine and might save us some power. Didn't know that clk_enable()/clk_disable() never sleeps and yes it should be infrequent triggered. I don't think that we can save a measureable amount of power since this is Low-Power IP clocked by a low-power clock. However, this was just my point of view. > > > + > > > return IRQ_HANDLED; > > > } > > > > > > @@ -140,6 +149,23 @@ static int imx_snvs_pwrkey_probe(struct platform_device *pdev) > > > if (pdata->irq < 0) > > > return -EINVAL; > > > > > > + pdata->clk = devm_clk_get_optional(&pdev->dev, "snvs-pwrkey"); > > > + if (IS_ERR(pdata->clk)) > > > + return PTR_ERR(pdata->clk); > > > + > > > + error = clk_prepare(pdata->clk); > > > + if (error) { > > > + dev_err(&pdev->dev, "failed to prepare the snvs clock\n"); > > > + return error; > > > + } > > > + error = devm_add_action_or_reset(&pdev->dev, > > > + (void(*)(void *))clk_unprepare, > > > + pdata->clk); > > > > I'm not a fan about those casts. However, the intentation should be > > fixed. > > Yes, can we please create a proper function for this (or maybe we will > finally get devm clk API?). devm_clk API +1 :) Regards, Marco