Hi Lee, 2017-05-23 16:05 GMT+09:00 Lee Jones <lee.jones@xxxxxxxxxx>: > On Tue, 23 May 2017, Masahiro Yamada wrote: > >> Hi Lee, Linus, >> >> Thanks for your comments! >> >> 2017-05-22 17:43 GMT+09:00 Linus Walleij <linus.walleij@xxxxxxxxxx>: >> > On Mon, May 22, 2017 at 3:29 AM, Masahiro Yamada >> > <yamada.masahiro@xxxxxxxxxxxxx> wrote: >> > >> >> Because "simple-bus" indicates that child nodes are >> >> simply memory mapped, but the node "register-bit-led" >> >> can not be memory-mapped. >> >> So, "simple-mfd" can not be replaced "simple-bus" here. >> > >> > Yeah... just like Lee points out, you are spot on, this is exactly >> > the reason why we created "simple-mfd" in the first place >> > IIRC. >> >> OK, Linux treats simple-bus and simple-mfd in the same way >> as far as I see drivers/of/platform.c > > Correct. As I said, the functionality of the two are the same. The > difference is their meaning. Initially we were using "simple-mfd" to > achieve our aim (see below), but there was push-back due to the > differences in what the two properties were trying to achieve. Ergo, > we introduced a second property. > >> Perhaps, can we document the difference between simple-bus and >> simple-mfd clearly? >> For example, "Unlike simple-bus, it is legitimate that simple-mfd has >> subnodes without reg property" >> >> >> I think this is typical when "simple-mfd" is used together with "syscon". >> The child devices will use regmap of the parent node. >> I'd like to be sure this is valid usage. > > "simple-mfd" simply means "register all of my child nodes using the > platform API without any further intervention". It's goal is to > prevent the MFD subsystem from being stuffed full of drivers where > their only purpose is to call of_platform_populate(). All other rules > and policy which must be followed are generic DT ones. To that end, I > do not believe making further statements is necessary. I see. Thanks for your kind explanation! -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
