From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerry Hoemann Subject: Re: [PATCHv2] watchdog: qcom: Add suspend/resume support Date: Thu, 17 Jan 2019 14:14:10 -0700 Message-ID: <20190117211410.GA30749@anatevka> References: <20190117151942.6092-1-saiprakash.ranjan@codeaurora.org> <154775022743.169631.1716489383315213219@swboyd.mtv.corp.google.com> Reply-To: Jerry.Hoemann@hpe.com Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Guenter Roeck Cc: linux-arm-kernel@lists.infradead.org, Sai Prakash Ranjan , Rajendra Nayak , linux-watchdog@vger.kernel.org, linux-kernel , Doug Anderson , Stephen Boyd , Sibi Sankar , Vivek Gautam , linux-arm-msm@vger.kernel.org, Guenter Roeck , Wim Van Sebroeck , Guenter Roeck List-Id: linux-arm-msm@vger.kernel.org On Thu, Jan 17, 2019 at 11:09:31AM -0800, Guenter Roeck wrote: > On Thu, Jan 17, 2019 at 10:37 AM Stephen Boyd wrote: > > > > Quoting Sai Prakash Ranjan (2019-01-17 07:19:42) > > > diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c > > > index 780971318810..5dfd604477a4 100644 > > > --- a/drivers/watchdog/qcom-wdt.c > > > +++ b/drivers/watchdog/qcom-wdt.c > > > @@ -245,6 +245,28 @@ static int qcom_wdt_remove(struct platform_device *pdev) > > > return 0; > > > } > > > > > > +static int __maybe_unused qcom_wdt_suspend(struct device *dev) > > > +{ > > > + struct qcom_wdt *wdt = dev_get_drvdata(dev); > > > + > > > + if (watchdog_active(&wdt->wdd)) > > > + qcom_wdt_stop(&wdt->wdd); > > > + > > > + return 0; > > > +} > > > + > > > +static int __maybe_unused qcom_wdt_resume(struct device *dev) > > > +{ > > > + struct qcom_wdt *wdt = dev_get_drvdata(dev); > > > + > > > + if (watchdog_active(&wdt->wdd)) > > > + qcom_wdt_start(&wdt->wdd); > > > + > > > + return 0; > > > +} > > > > This looks fairly generic. For example, the Mediatek driver also stops > > and starts (but also pings after starting). Grepping for 'active' in > > drivers/watchdog/ finds more examples. Could there be some functions in > > watchdog core that do the common things like watchdog_stop() and > > watchdog_start() and watchdog_start_and_ping()? Or maybe a bit can be > > set during registration so that the 'struct class watchdog_class' can > > get PM ops to stop and start on suspend/resume of the watchdog character > > device? > > > > Nothing is wrong with the patch, I'm just bemoaning the amount of code > > duplication here. > > > > Patch(es) to add the functionality to the watchdog core are welcome; > it should be possible to move the functionality into the core (maybe > to be enabled with a new watchdog API call). Doing it using the class > device sounds like an excellent idea. This should be straightforward > to implement, though the question of "should we ping on resume or not" > might be an endless source for bike shedding fun. > > Guenter It could be controlled by a currently unused bit in the watchdog_info.options. Then people can agree to disagree. -- ----------------------------------------------------------------------------- Jerry Hoemann Software Engineer Hewlett Packard Enterprise -----------------------------------------------------------------------------