From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1dYB2K-0005Zu-15 for linux-mtd@lists.infradead.org; Thu, 20 Jul 2017 12:58:37 +0000 Message-ID: <1500555312.2354.75.camel@pengutronix.de> Subject: Re: [PATCH 000/102] Convert drivers to explicit reset API From: Philipp Zabel To: Thomas Petazzoni Cc: linux-kernel@vger.kernel.org, Andrew Lunn , Prashant Gaikwad , Heiko Stuebner , Peter Chen , Linus Walleij , dri-devel@lists.freedesktop.org, Marc Dietrich , Rakesh Iyer , Peter Meerwald-Stadler , linux-clk@vger.kernel.org, Wim Van Sebroeck , Wolfram Sang , Xinliang Liu , Chanwoo Choi , Alan Stern , Jiri Slaby , Michael Turquette , Guenter Roeck , Ohad Ben-Cohen , linux-pm@vger.kernel.org, Thomas Gleixner , Vincent Abriou , Bin Liu , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, Ralf Baechle , linux-spi@vger.kernel.org, linux-crypto@vger.kernel.org, Tejun Heo , alsa-devel@alsa-project.org, linux-doc@vger.kernel.org, David Airlie , nouveau@lists.freedesktop.org, Philippe Cornu , Kalle Valo , Laxman Dewangan , Corentin Labbe , linux-i2c@vger.kernel.org, linux-watchdog@vger.kernel.org, Boris Brezillon , Lars-Peter Clausen , Emilio =?ISO-8859-1?Q?L=F3pez?= , Daniel Lezcano , Jon Hunter , linux-rockchip@lists.infradead.org, MyungJoo Ham , Ben Skeggs , Yisen Zhuang , linux-media@vger.kernel.org, Richard Zhu , Alexandre Torgue , Mathias Nyman , linux-arm-msm@vger.kernel.org, Joachim Eastwood , linux-gpio@vger.kernel.org, linux-mips@linux-mips.org, Bjorn Helgaas , Giuseppe Cavallaro , linux-arm-kernel@lists.infradead.org, Patrice Chotard , Stanimir Varbanov , Kyungmin Park , Maxime Coquelin , Hartmut Knaack , Jonathan Cameron , Ulf Hansson , linux-iio@vger.kernel.org, linux-pci@vger.kernel.org, Shawn Lin , linux-tegra@vger.kernel.org, linux-mtd@lists.infradead.org, Benjamin Gaignard , Florian Fainelli , Jonathan Corbet , Xinwei Kong , ath10k@lists.infradead.org, Kishon Vijay Abraham I , Chen-Yu Tsai , linux-input@vger.kernel.org, linux-pwm@vger.kernel.org, Chen Feng , Mark Brown , Dan Williams , Felipe Balbi , Salil Mehta , Dmitry Torokhov , linux-mmc@vger.kernel.org, Liam Girdwood , Thierry Reding , Cyrille Pitchen , Srinivas Kandagatla , Maxime Ripard , Brian Norris , "David S. Miller" , linux-remoteproc@vger.kernel.org, Bjorn Andersson , linux-ide@vger.kernel.org, Lee Jones , devel@driverdev.osuosl.org, Yannick Fertre , Ryder Lee , Herbert Xu , Richard Weinberger , Jaehoon Chung , Marek Vasut , linux-serial@vger.kernel.org, Zhang Rui , Alan Tull , John Youn , Eduardo Valentin , dmaengine@vger.kernel.org, linux-mediatek@lists.infradead.org, Matthias Brugger , Mark Yao , Moritz Fischer , Vivien Didelot , netdev@vger.kernel.org, Peter De Schrijver , Stephen Boyd , Adrian Hunter , Vinod Koul , Rongrong Zou , linux-fpga@vger.kernel.org, David Woodhouse , Lucas Stach Date: Thu, 20 Jul 2017 14:55:12 +0200 In-Reply-To: <20170720123640.43c2ce01@windsurf> References: <20170719152646.25903-1-p.zabel@pengutronix.de> <20170719211515.46a1196c@windsurf> <1500543415.2354.37.camel@pengutronix.de> <20170720123640.43c2ce01@windsurf> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Thomas, On Thu, 2017-07-20 at 12:36 +0200, Thomas Petazzoni wrote: > Hello, > > On Thu, 20 Jul 2017 11:36:55 +0200, Philipp Zabel wrote: > > > > I don't know if it has been discussed in the past, so forgive me if it > > > has been. Have you considered adding a "int flags" argument to the > > > existing reset_control_get_*() functions, rather than introducing > > > separate exclusive variants ? > > > > > > Indeed, with a "int flags" argument you could in the future add more > > > variants/behaviors without actually multiplying the number of > > > functions. Something like the "flags" argument for request_irq() for > > > example. > > > > I can't find the discussion right now, but I remember we had talked > > about this in the past. > > Behind the scenes, all the inline API functions already call common > > entry points with flags (well, currently separate bool parameters for > > shared and optional). > > One reason against exposing those as an int flags in the user facing API > > is the possibility to accidentally provide a wrong value. > > This is a quite strange argument. You could also accidentally use the > wrong variant of the function, just like you could use the wrong flag. You can't accidentally use no flag at all or a completely bogus value with the "plethora of inline functions" variant. > Once again, the next time you have another parameter for those reset > functions, beyond the exclusive/shared variant, you will multiply again > by two the number of functions ? You already have the exclusive/shared > and optional/mandatory variants, so 4 variants. When you'll add a new > parameter, you'll have 8 variants. Doesn't seem really good. I'd rather avoid adding more variants, if possible. The complexity increases regardless of whether the API is expressed as a bunch of functions or as a single function with a bunch of flags. > What about reset_control_get(struct device *, const char *, int flags) > to replace all those variants ? While I like how this looks, unfortunately (devm_)reset_control_get already exists without the flags, so we can't change to that with a gentle transition. regards Philipp