From: Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org> To: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>, Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Cc: linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org" <linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>, "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" <linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org> Subject: reason for Allwinner SoC specific pinctrl drivers? Date: Mon, 4 Jan 2016 11:02:37 +0000 [thread overview] Message-ID: <568A514D.7070102@arm.com> (raw) Hi, while looking at the Allwinner A64 SoC support, I was wondering why we would actually need a pinctrl driver (file) for each and every Allwinner SoC that we support. Looking at both the A20 and the A64 doc I don't see any differences in the port controller implementation apart from the actual muxval <-> subsystem assignment, which is just data, right? Comparing the code files in drivers/pinctrl/sunxi seems to support this, as those drivers only consist of the table and some boilerplate code. Now I was wondering whether we could get away with one generic Allwinner pinctrl driver and put the SoC specific pin assignments in DT instead. It looks like adding an "allwinner,muxval" property in addition to the existing "allwinner,function" in the SoC's .dtsi would give us all the information we need. This could look like: uart0_pins_a: uart0@0 { allwinner,pins = "PB22", "PB23"; + allwinner,muxval = <0x02 0x02>; allwinner,function = "uart0"; allwinner,drive = <SUN4I_PINCTRL_10_MA>; allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; }; Would it make sense that I sit down and prototype such a driver? We should keep compatibility with older DTs by keeping the existing drivers in (or maybe emulating the current behaviour by providing just those tables as a fallback) , but newer SoCs (like the A64?) would not need a SoC specific driver, but just go with that generic driver and appropriate DT properties. I appreciate any comments on this, especially if I missed something which would render this approach impossible or tedious. Cheers, Andre.
WARNING: multiple messages have this Message-ID (diff)
From: andre.przywara@arm.com (Andre Przywara) To: linux-arm-kernel@lists.infradead.org Subject: reason for Allwinner SoC specific pinctrl drivers? Date: Mon, 4 Jan 2016 11:02:37 +0000 [thread overview] Message-ID: <568A514D.7070102@arm.com> (raw) Hi, while looking at the Allwinner A64 SoC support, I was wondering why we would actually need a pinctrl driver (file) for each and every Allwinner SoC that we support. Looking at both the A20 and the A64 doc I don't see any differences in the port controller implementation apart from the actual muxval <-> subsystem assignment, which is just data, right? Comparing the code files in drivers/pinctrl/sunxi seems to support this, as those drivers only consist of the table and some boilerplate code. Now I was wondering whether we could get away with one generic Allwinner pinctrl driver and put the SoC specific pin assignments in DT instead. It looks like adding an "allwinner,muxval" property in addition to the existing "allwinner,function" in the SoC's .dtsi would give us all the information we need. This could look like: uart0_pins_a: uart0 at 0 { allwinner,pins = "PB22", "PB23"; + allwinner,muxval = <0x02 0x02>; allwinner,function = "uart0"; allwinner,drive = <SUN4I_PINCTRL_10_MA>; allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; }; Would it make sense that I sit down and prototype such a driver? We should keep compatibility with older DTs by keeping the existing drivers in (or maybe emulating the current behaviour by providing just those tables as a fallback) , but newer SoCs (like the A64?) would not need a SoC specific driver, but just go with that generic driver and appropriate DT properties. I appreciate any comments on this, especially if I missed something which would render this approach impossible or tedious. Cheers, Andre.
next reply other threads:[~2016-01-04 11:02 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-01-04 11:02 Andre Przywara [this message] 2016-01-04 11:02 ` reason for Allwinner SoC specific pinctrl drivers? Andre Przywara [not found] ` <568A514D.7070102-5wv7dgnIgG8@public.gmane.org> 2016-01-04 17:27 ` Vishnu Patekar [not found] ` <CAEzqOZu8wkPKLp6bZZ7JuiM07ixDksdD=U-WK=3kFPYJZMon4Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2016-01-04 21:36 ` Michal Suchanek 2016-01-04 21:36 ` [linux-sunxi] " Michal Suchanek [not found] ` <CAOMqctQL3nmWECpQgtVdxgzEfn2obu4cdj67W1ESONO=5EpQdQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2016-01-05 12:05 ` Andre Przywara 2016-01-05 12:05 ` [linux-sunxi] " Andre Przywara 2016-01-05 15:20 ` Michal Suchanek 2016-01-05 15:20 ` Michal Suchanek 2016-01-04 22:04 ` Julian Calaby 2016-01-04 22:04 ` [linux-sunxi] " Julian Calaby [not found] ` <CAGRGNgUVNGoOUNqyySjYzkL4KfEWK8orYH-AMxoCX-9N0R80-A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2016-01-05 12:24 ` Andre Przywara 2016-01-05 12:24 ` [linux-sunxi] " Andre Przywara 2016-01-05 13:10 ` Maxime Ripard 2016-01-05 13:10 ` Maxime Ripard 2016-01-07 10:06 ` Linus Walleij 2016-01-07 10:06 ` Linus Walleij 2016-01-05 2:21 ` [linux-sunxi] " Chen-Yu Tsai 2016-01-05 2:21 ` Chen-Yu Tsai
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