lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 3 Sep 2012 10:31:03 +0800 From: Dong Aisheng <b29396@...escale.com> To: Shawn Guo <shawn.guo@...aro.org> CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, "linus.walleij@...ricsson.com" <linus.walleij@...ricsson.com>, "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>, "kernel@...gutronix.de" <kernel@...gutronix.de>, "grant.likely@...retlab.ca" <grant.likely@...retlab.ca>, "rob.herring@...xeda.com" <rob.herring@...xeda.com>, "sameo@...ux.intel.com" <sameo@...ux.intel.com>, "lrg@...com" <lrg@...com>, "broonie@...nsource.wolfsonmicro.com" <broonie@...nsource.wolfsonmicro.com>, Zhao Richard-B20223 <B20223@...escale.com>, "devicetree-discuss@...ts.ozlabs.org" <devicetree-discuss@...ts.ozlabs.org>, "swarren@...dotorg.org" <swarren@...dotorg.org> Subject: Re: [PATCH v4 1/7] mfd: add syscon driver based on regmap On Fri, Aug 31, 2012 at 09:26:29AM +0800, Shawn Guo wrote: > On Wed, Aug 29, 2012 at 06:56:52PM +0800, Dong Aisheng wrote: > > +config MFD_SYSCON > > + bool "System Controller Register R/W Based on Regmap" > > If the driver only compiles and works for device tree probe, we should > have the following? > > depends on OF > Correct. For currently it only supports dt. > > + select REGMAP_MMIO > > + help > > + Select this option to enable accessing system control registers > > + via regmap. > > + > > <snip> > > > +struct regmap *syscon_node_to_regmap(struct device_node *np) > > +{ > > + struct syscon *syscon; > > + struct device *dev; > > + > > + dev = driver_find_device(&syscon_driver.driver, NULL, np, > > + syscon_match); > > + of_node_put(np); > > This looks a little unnatural to me. Function syscon_node_to_regmap > becomes an API visible to clients, who might never know that np will > be put inside the API. I'm saying the client may also call of_node_put > to put the node they get. We probably could add a comment here for the API to avoid this happen. > > I think of_node_put should be moved out from here and put into > syscon_node_to_regmap and syscon_regmap_lookup_by_compatible. > I guess no, if you want to move of_node_put into syscon_regmap_lookup_by_phandle, then syscon_regmap_lookup_by_phandle has the same issue. Actually i had considered your concern when writing this API... The original purpose of doing like that is saving some duplicated 'of_node_put' and make the API easy to use. I searched the kernel dt code and found it existed some similar cases. e.g: of_irq_find_parent, of_get_next_parent So it looks to me that it may be usually to do like that for the cases that the conversion from a node to other thing since the client may only care about the things converted. For our case, it's regmap. So i can't think it make too much sense for all client driver have to write duplicated and meaningless 'of_node_put' code. Regards Dong Aisheng > > + > > + if (!dev) > > + return ERR_PTR(-EPROBE_DEFER); > > + > > + syscon = dev_get_drvdata(dev); > > + > > + return syscon->regmap; > > +} > > +EXPORT_SYMBOL_GPL(syscon_node_to_regmap); > > + > > +struct regmap *syscon_regmap_lookup_by_compatible(const char *s) > > +{ > > + struct device_node *syscon_np; > > + > > + syscon_np = of_find_compatible_node(NULL, NULL, s); > > + if (!syscon_np) > > + return ERR_PTR(-ENODEV); > > + > > + return syscon_node_to_regmap(syscon_np); > > +} > > +EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); > > + > > +struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, > > + const char *property) > > +{ > > + struct device_node *syscon_np; > > + > > + syscon_np = of_parse_phandle(np, property, 0); > > + if (!syscon_np) > > + return ERR_PTR(-ENODEV); > > + > > + return syscon_node_to_regmap(syscon_np); > > +} > > +EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists