Date: Sun, 19 Aug 2012 17:42:01 -0600 From: Warner Losh <imp@bsdimp.com> To: Tim Kientzle <tim@kientzle.com> Cc: gonzo@freebsd.org, freebsd-arm@freebsd.org Subject: Re: gpiobus_hinted_child >32 pins support, pin_getname method, and gpio-sysctl bridge patch Message-ID: <974EEF9B-08C2-4876-9223-48DD4ABDFC99@bsdimp.com> In-Reply-To: <12A967D8-BC49-49AF-BBD9-40E259932617@kientzle.com> References: <20120819.171723.523519054460575158.hrs@allbsd.org> <8CDAB51C-14A0-42F0-8E16-43A3EABA2703@bsdimp.com> <E7C5ED5C-7120-4B69-9146-D9CC7A8E14C2@kientzle.com> <7E6C76BE-1D3F-40E4-BFE3-DC88715C234C@bsdimp.com> <12A967D8-BC49-49AF-BBD9-40E259932617@kientzle.com>
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On Aug 19, 2012, at 5:04 PM, Tim Kientzle wrote: > On Aug 19, 2012, at 10:02 AM, Warner Losh wrote: >>=20 >> On Aug 19, 2012, at 10:03 AM, Tim Kientzle wrote: >>=20 >>> On Aug 19, 2012, at 8:38 AM, Warner Losh wrote: >>>=20 >>>>=20 >>>> In general, I like this code in the context of the current GPIO = framework. I've been growing dissatisfied with the current GPIO = framework, however, and some of my comments reflect that more than any = comments about this specific code. >>>=20 >>> I noticed that Linux on BeagleBone does not >>> simply number all pins as we do. Pins are identified by >>> two numbers: a unit number and a pin number. >>=20 >> Is this in the code, or just in the FTD? On Atmel, there's a single = number from 0 to max-1 with all negative numbers being invalid. But = Atmel doesn't have proper FTD support in Linux just yet (3.5 has a good = start, and 3.6 will add the missing pinmux/pinctl stuff). >=20 > I'm not exactly sure what you mean. The Linux DTS file: >=20 > = http://git.kernel.org/?p=3Dlinux/kernel/git/torvalds/linux.git;a=3Dblob;f=3D= arch/arm/boot/dts/am335x-bone.dts >=20 > inherits most of the real functionality from >=20 > = http://git.kernel.org/?p=3Dlinux/kernel/git/torvalds/linux.git;a=3Dblob;f=3D= arch/arm/boot/dts/am33xx.dtsi >=20 > There are certainly separate entries there for each GPIO module. I = presume (but haven't verified) that the unit number maps directly to a = "gpio#" device name. There's similar things in the Atmel DTS files, but under the covers the = gpio pins map into a uniform space number 0 to 32*N-1, where N is the = number of GPIO units. Warner=
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