From: Mitch Bradley <wmb@firmworks.com> To: Stephen Warren <swarren@wwwdotorg.org> Cc: Jon Loeliger <jdl@jdl.com>, Michal Marek <mmarek@suse.cz>, Stephen Warren <swarren@nvidia.com>, devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: dtc: import latest upstream dtc Date: Tue, 09 Oct 2012 13:20:53 -1000 [thread overview] Message-ID: <5074B155.4090703@firmworks.com> (raw) In-Reply-To: <50749441.8030307@wwwdotorg.org> On 10/9/2012 11:16 AM, Stephen Warren wrote: > On 10/01/2012 12:39 PM, Jon Loeliger wrote: >>> >>> What more do you think needs discussion re: dtc+cpp? >> >> How not to abuse the ever-loving shit out of it? :-) > > Perhaps we can just handle this through the regular patch review > process; I think it may be difficult to define and agree upon exactly > what "abuse" means ahead of time, but it's probably going to be easy > enough to recognize it when one sees it? One of the ways it could get out of hand would be via "include dependency hell". People will be tempted to reuse existing .h files containing pin definitions, which, if history is a guide, will end up depending on all sorts of other .h files. Another problem I often face with symbolic names is the difficulty of figuring out what the numerical values really are (for debugging), especially when .h files are in different subtrees from the files that use the definitions, and when they use multiple macro levels and fancy features like concatenation. Sometimes I think it's clearer just to write the number and use a comment to say what it is. > > I imagine the most common usage will simply be a bunch of: > > #define TEGRA_GPIO_PB0 32 > #define TEGRA_GPIO_INT_LEVEL_LOW 8 > > / { > xxx { > interrupts = <TEGRA_GPIO_PB0 TEGRA_GPIO_INT_LEVEL_LOW>; > > and similarly, simple math: > > something = <((FOO << XXX_SHIFT) | (BAR << YYY_SHIFT))>; > > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/devicetree-discuss >
WARNING: multiple messages have this Message-ID (diff)
From: Mitch Bradley <wmb-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org> To: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Cc: Michal Marek <mmarek-AlSwsSmVLrQ@public.gmane.org>, Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: dtc: import latest upstream dtc Date: Tue, 09 Oct 2012 13:20:53 -1000 [thread overview] Message-ID: <5074B155.4090703@firmworks.com> (raw) In-Reply-To: <50749441.8030307-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> On 10/9/2012 11:16 AM, Stephen Warren wrote: > On 10/01/2012 12:39 PM, Jon Loeliger wrote: >>> >>> What more do you think needs discussion re: dtc+cpp? >> >> How not to abuse the ever-loving shit out of it? :-) > > Perhaps we can just handle this through the regular patch review > process; I think it may be difficult to define and agree upon exactly > what "abuse" means ahead of time, but it's probably going to be easy > enough to recognize it when one sees it? One of the ways it could get out of hand would be via "include dependency hell". People will be tempted to reuse existing .h files containing pin definitions, which, if history is a guide, will end up depending on all sorts of other .h files. Another problem I often face with symbolic names is the difficulty of figuring out what the numerical values really are (for debugging), especially when .h files are in different subtrees from the files that use the definitions, and when they use multiple macro levels and fancy features like concatenation. Sometimes I think it's clearer just to write the number and use a comment to say what it is. > > I imagine the most common usage will simply be a bunch of: > > #define TEGRA_GPIO_PB0 32 > #define TEGRA_GPIO_INT_LEVEL_LOW 8 > > / { > xxx { > interrupts = <TEGRA_GPIO_PB0 TEGRA_GPIO_INT_LEVEL_LOW>; > > and similarly, simple math: > > something = <((FOO << XXX_SHIFT) | (BAR << YYY_SHIFT))>; > > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > https://lists.ozlabs.org/listinfo/devicetree-discuss >
next prev parent reply other threads:[~2012-10-09 23:21 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-09-28 21:25 [PATCH] dtc: import latest upstream dtc Stephen Warren 2012-09-29 21:06 ` Jon Loeliger 2012-10-01 16:09 ` Rob Herring 2012-10-01 16:13 ` Stephen Warren 2012-10-01 16:13 ` Stephen Warren 2012-10-01 17:56 ` Rob Herring 2012-10-01 17:56 ` Rob Herring 2012-10-01 18:33 ` Stephen Warren 2012-10-01 18:39 ` Jon Loeliger 2012-10-01 18:39 ` Jon Loeliger 2012-10-09 21:16 ` Stephen Warren 2012-10-09 21:16 ` Stephen Warren 2012-10-09 23:20 ` Mitch Bradley [this message] 2012-10-09 23:20 ` Mitch Bradley 2012-10-10 0:04 ` Scott Wood 2012-10-10 0:04 ` Scott Wood 2012-10-10 4:43 ` Warner Losh 2012-10-10 7:24 ` David Gibson 2012-10-10 14:41 ` Warner Losh 2012-10-10 14:41 ` Warner Losh 2012-10-10 23:06 ` David Gibson 2012-10-10 15:16 ` Stephen Warren 2012-10-10 15:33 ` Rob Herring 2012-10-10 16:19 ` Stephen Warren 2012-10-10 17:18 ` Rob Herring 2012-10-10 18:42 ` Stephen Warren 2012-10-10 23:16 ` David Gibson 2012-10-10 23:16 ` David Gibson 2012-10-11 1:42 ` Mitch Bradley 2012-10-11 5:11 ` David Gibson 2012-10-11 5:11 ` David Gibson 2012-10-10 23:09 ` David Gibson 2012-10-10 23:09 ` David Gibson 2012-10-10 15:15 ` Stephen Warren 2012-10-10 15:15 ` Stephen Warren 2012-10-10 16:09 ` Scott Wood 2012-10-10 16:09 ` Scott Wood 2012-10-10 16:22 ` Stephen Warren 2012-10-10 23:18 ` David Gibson 2012-10-12 17:24 ` Stephen Warren 2012-10-13 6:24 ` David Gibson 2012-10-13 6:24 ` David Gibson 2012-10-13 13:42 ` Segher Boessenkool 2012-10-13 13:42 ` Segher Boessenkool 2012-10-14 0:16 ` David Gibson 2012-10-14 0:16 ` David Gibson 2012-10-10 17:09 ` Rob Herring 2012-10-10 18:23 ` Mitch Bradley 2012-10-10 18:23 ` Mitch Bradley 2012-10-10 18:45 ` Stephen Warren 2012-10-10 18:45 ` Stephen Warren 2012-10-10 18:56 ` Mitch Bradley 2012-10-10 18:56 ` Mitch Bradley 2012-10-11 0:14 ` David Gibson 2012-10-10 23:54 ` David Gibson 2012-10-10 18:40 ` Stephen Warren 2012-10-10 18:52 ` Mitch Bradley 2012-10-10 18:52 ` Mitch Bradley 2012-10-01 18:02 ` Jon Loeliger 2012-10-01 18:02 ` Jon Loeliger
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