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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 4AB69C433DF for ; Wed, 27 May 2020 11:26:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A97E207D3 for ; Wed, 27 May 2020 11:26:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="HNG5uEkg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725820AbgE0L0d (ORCPT ); Wed, 27 May 2020 07:26:33 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:50175 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730000AbgE0L0c (ORCPT ); Wed, 27 May 2020 07:26:32 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1590578791; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=P25q6ipZ3riPqbhrRJ+PtUgnCNFkPSplK5OpM68AuG8=; b=HNG5uEkg+kSlBg6UuwArUwYgzDXXGC9SfQZ0cwqQ4PbC/fc9ggZ2+wH9dEWxIsrV/mrRJlA/ cL45QIn8BjKZAytAatjIZjivveAvAYDcqHsdNGy2JtyomVQQIpcZkEB0xjqlHLRtie07JeqZ bw/45WADn3xycSiQXRw4bekCl8Q= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n01.prod.us-west-2.postgun.com with SMTP id 5ece4e6037a454afcbcfe36e (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 27 May 2020 11:26:24 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id A0AF8C433B1; Wed, 27 May 2020 11:26:24 +0000 (UTC) Received: from [192.168.43.129] (unknown [106.222.1.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mkshah) by smtp.codeaurora.org (Postfix) with ESMTPSA id 8AFE3C433C9; Wed, 27 May 2020 11:26:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 8AFE3C433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=mkshah@codeaurora.org Subject: Re: [PATCH v2 1/4] gpio: gpiolib: Allow GPIO IRQs to lazy disable To: Stephen Boyd , bjorn.andersson@linaro.org, evgreen@chromium.org, linus.walleij@linaro.org, maz@kernel.org, mka@chromium.org Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-gpio@vger.kernel.org, agross@kernel.org, tglx@linutronix.de, jason@lakedaemon.net, dianders@chromium.org, rnayak@codeaurora.org, ilina@codeaurora.org, lsrao@codeaurora.org References: <1590253873-11556-1-git-send-email-mkshah@codeaurora.org> <1590253873-11556-2-git-send-email-mkshah@codeaurora.org> <159057264232.88029.4708934729701385486@swboyd.mtv.corp.google.com> From: Maulik Shah Message-ID: <4e070cda-8c22-c554-610e-172320045840@codeaurora.org> Date: Wed, 27 May 2020 16:56:14 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <159057264232.88029.4708934729701385486@swboyd.mtv.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-GB Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi, On 5/27/2020 3:14 PM, Stephen Boyd wrote: > Quoting Maulik Shah (2020-05-23 10:11:10) >> With 'commit 461c1a7d4733 ("gpiolib: override irq_enable/disable")' gpiolib >> overrides irqchip's irq_enable and irq_disable callbacks. If irq_disable >> callback is implemented then genirq takes unlazy path to disable irq. >> >> Underlying irqchip may not want to implement irq_disable callback to lazy >> disable irq when client drivers invokes disable_irq(). By overriding >> irq_disable callback, gpiolib ends up always unlazy disabling IRQ. >> >> Allow gpiolib to lazy disable IRQs by overriding irq_disable callback only >> if irqchip implemented irq_disable. In cases where irq_disable is not >> implemented irq_mask is overridden. Similarly override irq_enable callback >> only if irqchip implemented irq_enable otherwise irq_unmask is overridden. >> >> Fixes: 461c1a7d47 (gpiolib: override irq_enable/disable) > This isn't a proper Fixes line. Should have quotes > > Fixes: 461c1a7d4733 ("gpiolib: override irq_enable/disable") Thanks for pointing this, i will address in next revision. > >> Signed-off-by: Maulik Shah >> --- >> drivers/gpio/gpiolib.c | 55 +++++++++++++++++++++++++++++---------------- >> include/linux/gpio/driver.h | 13 +++++++++++ >> 2 files changed, 49 insertions(+), 19 deletions(-) >> >> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c >> index eaa0e20..3810cd0 100644 >> --- a/drivers/gpio/gpiolib.c >> +++ b/drivers/gpio/gpiolib.c >> @@ -2465,32 +2465,37 @@ static void gpiochip_irq_relres(struct irq_data *d) >> gpiochip_relres_irq(gc, d->hwirq); >> } >> >> +static void gpiochip_irq_mask(struct irq_data *d) >> +{ >> + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); >> + >> + if (gc->irq.irq_mask) >> + gc->irq.irq_mask(d); >> + gpiochip_disable_irq(gc, d->hwirq); > How does this work in the lazy case when I want to drive the GPIO? Say I > have a GPIO that is also an interrupt. The code would look like > > struct gpio_desc *gpio = gpiod_get(...) > unsigned int girq = gpiod_to_irq(gpio) > > request_irq(girq, ...); > > disable_irq(girq); > gpiod_direction_output(gpio, 1); > > In the lazy case genirq wouldn't call the mask function until the first > interrupt arrived on the GPIO line. If that never happened then wouldn't > we be blocked in gpiod_direction_output() when the test_bit() sees > FLAG_USED_AS_IRQ? Or do we need irqs to be released before driving > gpios? The client driver can decide to unlazy disable IRQ with below API...  irq_set_status_flags(girq, IRQ_DISABLE_UNLAZY); This will immediatly invoke mask function (unlazy disable) from genirq, even though irq_disable is not implemented. Thanks, Maulik > >> +} >> + >> +static void gpiochip_irq_unmask(struct irq_data *d) >> +{ >> + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); >> + >> + gpiochip_enable_irq(gc, d->hwirq); >> + if (gc->irq.irq_unmask) >> + gc->irq.irq_unmask(d); >> +} >> + -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation