From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754831AbcDKMhT (ORCPT ); Mon, 11 Apr 2016 08:37:19 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:45247 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754563AbcDKMhR (ORCPT ); Mon, 11 Apr 2016 08:37:17 -0400 Reply-To: Subject: Re: [PATCH v7 3/3] gpio: dwapb: add gpio-signaled acpi event support References: <1459926480-32966-1-git-send-email-qiujiang@huawei.com> <1459926480-32966-4-git-send-email-qiujiang@huawei.com> To: Linus Walleij CC: Alexandre Courbot , Mika Westerberg , Andy Shevchenko , Alan Tull , "Jamie Iles" , , "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" , "ACPI Devel Maling List" , Linuxarm From: Jiang Qiu Message-ID: <570B9996.10402@huawei.com> Date: Mon, 11 Apr 2016 20:33:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.74.160.152] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.570B99A4.00ED,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: fd172d1207c863a08fd01bb5b99277e1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2016/4/8 16:26, Linus Walleij 写道: > On Wed, Apr 6, 2016 at 9:08 AM, qiujiang wrote: > >> This patch adds gpio-signaled acpi event support. It is used for >> power button on hisilicon D02 board, an arm64 platform. >> >> The corresponding DSDT file is defined as follows: >> Device(GPI0) { >> Name(_HID, "HISI0181") >> Name(_ADR, 0) >> Name(_UID, 0) >> >> Name (_CRS, ResourceTemplate () { >> Memory32Fixed (ReadWrite, 0x802e0000, 0x10000) >> Interrupt (ResourceConsumer, Level, ActiveHigh, >> Exclusive,,,) {344} >> }) >> >> Device(PRTa) { >> Name (_DSD, Package () { >> Package () { >> Package () {"reg",0}, >> Package () {"snps,nr-gpios",32}, >> } >> }) >> } >> >> Name (_AEI, ResourceTemplate () { >> GpioInt(Edge, ActiveLow, ExclusiveAndWake, >> PullUp, , " \\_SB.GPI0") {8} >> }) >> >> Method (_E08, 0x0, NotSerialized) { >> Notify (\_SB.PWRB, 0x80) >> } >> } >> >> Acked-by: Mika Westerberg >> Reviewed-by: Andy Shevchenko >> Signed-off-by: qiujiang > Admittedly I'm an ACPI novice and need help with deciding > about ACPI, but I mostly trust Mika to know these things right. > > About this: > >> + /* Add GPIO-signaled ACPI event support */ >> + if (pp->irq) >> + acpi_gpiochip_request_interrupts(&port->gc); > It's weird to me that the driver already has a requested IRQ and > everything, now it has to request it again from ACPI. > > When I look into the acpi_gpiochip_request_interrupts() > I find it weird that it is void given how much can go wrong > inside it. Should it not return an errorcode? Just as Mika said, these are two different things: platform_get_irq() requestedIRQ resource from interrupt subsystem and create irq mapping, then gose ready for device, but dose not request a handler immediately. acpi_gpiochip_request_interrupts() parse the _AEI and _EVT object and result awareness of what GPIO pin is used.Then, install a event handler for each pin by request this pp->irq. If something gose wrong when acpi_gpiochip_request_interrupts() process, GPIO itself can still works fine. >> + if (has_acpi_companion(dev) && pp->idx == 0) >> + pp->irq = platform_get_irq(to_platform_device(dev), 0); > As it was already fetched here and then later requested, > we still have to call acpi_gpiochip_request_interrupts() > further down the road? That is confusing to me, can you > explain what is going on? > > Yours, > Linus Walleij > > . >