From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: [PATCH v11 2/8] mfd: bd70528: Support ROHM bd70528 PMIC - core Date: Thu, 4 Apr 2019 09:56:40 +0200 Message-ID: <20190404075640.GV22216@piout.net> References: <20190403073152.GM4187@dell> <20190403084732.GA3493@localhost.localdomain> <20190403093015.GJ11301@dell> <20190403101003.GC3493@localhost.localdomain> <20190403112559.GP11301@dell> <85b20828bb4fb51e6df1d5d9d1c1f667db3a7c48.camel@fi.rohmeurope.com> <20190404025234.GB6830@dell> <6775a75d1ee3ab96123d84b077881beedc358d12.camel@fi.rohmeurope.com> <20190404065452.GD6830@dell> <20190404072449.GE3493@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190404072449.GE3493@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org To: Matti Vaittinen Cc: Lee Jones , "robh+dt@kernel.org" , "mazziesaccount@gmail.com" , "mturquette@baylibre.com" , "devicetree@vger.kernel.org" , "linux-pm@vger.kernel.org" , "sre@kernel.org" , "linus.walleij@linaro.org" , "sboyd@kernel.org" , "linux-gpio@vger.kernel.org" , "a.zummo@towertech.it" , "broonie@kernel.org" , "Mutanen, Mikko" , "mark.rutland@arm.com" , "linux-watchdog@vger.kernel.org" , "linux@roeck-us.net" List-Id: devicetree@vger.kernel.org On 04/04/2019 10:24:49+0300, Matti Vaittinen wrote: > On Thu, Apr 04, 2019 at 07:54:52AM +0100, Lee Jones wrote: > > On Thu, 04 Apr 2019, Vaittinen, Matti wrote: > > > > > Actually, now that I thik of it the right way to do this would have > > > been the function pointer in parent data as was done in original patch > > > set. HW-colleagues tend to re-use HW blocks, and we like to re-use our > > > drivers. If the next PMIC from ROHM uses same RTC block but does not > > > provide watchdog - then it is cleanest solution to fall back to > > > function pointer and leave it to NULL when there is no WDT or when WDT > > > is unused. Another option is to export dummy function - which is not so > > > nice. > > > > I think the converse is true. > > > > Pointers to functions outside of a subsystem API context are generally > > horrible. It's much nicer to call a function which can be easily > > stubbed out in a header file based on a Kconfig option. It's how most > > kernel APIs work. > > I hate to admit but I see your point. This nicely solves any issues in > syncronizing the startup for driver providing function pointer and for > driver using it. > Wouldn't it be easier to register the watchdog driver as part of the RTC driver? As I see it, the wdt is just a glorified RTC alarm. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com