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From: Scott Wood <scottwood@freescale.com>
To: "Cousson, Benoit" <b-cousson@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>,
	"Hilman, Kevin" <khilman@ti.com>, Paul Walmsley <paul@pwsan.com>,
	"G, Manjunath Kondaiah" <manjugk@ti.com>,
	"devicetree-discuss@lists.ozlabs.org"
	<devicetree-discuss@lists.ozlabs.org>,
	linux-omap <linux-omap@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: How to handle named resources with DT?
Date: Tue, 9 Aug 2011 13:26:29 -0500	[thread overview]
Message-ID: <4E417BD5.8080409@freescale.com> (raw)
In-Reply-To: <4E4172A8.3030101@ti.com>

On 08/09/2011 12:47 PM, Cousson, Benoit wrote:
> On 8/9/2011 7:23 PM, Grant Likely wrote:
>> There is no analogous mechanism for _byname in the device tree.  The
>> DT binding for a device must explicitly state what order the register
>> ranges are in.  The driver will need to be adapted.
> 
> That seems to be a small regression for my point of view. Relying on the
> order is not super safe. This is not very readable either. That's for
> that exact reason that we changed our drivers to use
> platform_get_resource_byname. That's probably the reason why that API is
> there as well.
> For the same IP, the number of entries can vary depending of the SoC
> revision.
> By using the _byname, we can check if the resource is there or not
> without having to care about the position.

You could have a named u32 property that contains the reg index, e.g.:

dev {
	reg = <0x20000 0x200 0x24000 0x200>;
	foo-reg = <0>;
	bar-reg = <1>;
};

-Scott


WARNING: multiple messages have this Message-ID (diff)
From: scottwood@freescale.com (Scott Wood)
To: linux-arm-kernel@lists.infradead.org
Subject: How to handle named resources with DT?
Date: Tue, 9 Aug 2011 13:26:29 -0500	[thread overview]
Message-ID: <4E417BD5.8080409@freescale.com> (raw)
In-Reply-To: <4E4172A8.3030101@ti.com>

On 08/09/2011 12:47 PM, Cousson, Benoit wrote:
> On 8/9/2011 7:23 PM, Grant Likely wrote:
>> There is no analogous mechanism for _byname in the device tree.  The
>> DT binding for a device must explicitly state what order the register
>> ranges are in.  The driver will need to be adapted.
> 
> That seems to be a small regression for my point of view. Relying on the
> order is not super safe. This is not very readable either. That's for
> that exact reason that we changed our drivers to use
> platform_get_resource_byname. That's probably the reason why that API is
> there as well.
> For the same IP, the number of entries can vary depending of the SoC
> revision.
> By using the _byname, we can check if the resource is there or not
> without having to care about the position.

You could have a named u32 property that contains the reg index, e.g.:

dev {
	reg = <0x20000 0x200 0x24000 0x200>;
	foo-reg = <0>;
	bar-reg = <1>;
};

-Scott

  parent reply	other threads:[~2011-08-09 18:26 UTC|newest]

Thread overview: 141+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-09  9:23 How to handle named resources with DT? Cousson, Benoit
2011-08-09  9:23 ` Cousson, Benoit
2011-08-09 16:29 ` G, Manjunath Kondaiah
2011-08-09 16:29   ` G, Manjunath Kondaiah
2011-08-09 16:57   ` Cousson, Benoit
2011-08-09 16:57     ` Cousson, Benoit
2011-08-09 17:23     ` Grant Likely
2011-08-09 17:23       ` Grant Likely
2011-08-09 17:47       ` Cousson, Benoit
2011-08-09 17:47         ` Cousson, Benoit
2011-08-09 17:52         ` Matt Porter
2011-08-09 17:52           ` Matt Porter
2011-08-09 18:26         ` Scott Wood [this message]
2011-08-09 18:26           ` Scott Wood
2011-08-09 20:57           ` Grant Likely
2011-08-09 20:57             ` Grant Likely
     [not found]             ` <20110809205723.GE11568-e0URQFbLeQY2iJbIjFUEsiwD8/FfD2ys@public.gmane.org>
2011-08-09 21:08               ` Cousson, Benoit
2011-08-09 21:08                 ` Cousson, Benoit
2011-08-09 21:17                 ` Grant Likely
2011-08-09 21:17                   ` Grant Likely
2011-08-09 21:44                   ` Cousson, Benoit
2011-08-09 21:44                     ` Cousson, Benoit
2011-08-09 21:49                     ` Grant Likely
2011-08-09 21:49                       ` Grant Likely
2011-08-09 21:53                       ` Cousson, Benoit
2011-08-09 21:53                         ` Cousson, Benoit
2011-08-10  1:52                         ` David Gibson
2011-08-10  1:52                           ` David Gibson
2011-08-10  7:11                           ` Paul Walmsley
2011-08-10  7:11                             ` Paul Walmsley
     [not found]                           ` <20110810015214.GD23511-787xzQ0H9iQXU02nzanrWNbf9cGiqdzd@public.gmane.org>
2011-08-10 15:01                             ` Cousson, Benoit
2011-08-10 15:01                               ` Cousson, Benoit
2011-08-10 15:18                           ` Scott Wood
2011-08-10 15:18                             ` Scott Wood
     [not found]                             ` <4E42A14B.9050308-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
2011-08-10 15:21                               ` Cousson, Benoit
2011-08-10 15:21                                 ` Cousson, Benoit
2011-08-10 19:22                           ` Grant Likely
2011-08-10 19:22                             ` Grant Likely
2011-08-10 19:57                             ` David Brown
2011-08-10 19:57                               ` David Brown
2011-08-10 20:12                               ` Grant Likely
2011-08-10 20:12                                 ` Grant Likely
2011-08-11 12:28                             ` Cousson, Benoit
2011-08-11 12:28                               ` Cousson, Benoit
2011-08-12  3:02                               ` David Gibson
2011-08-12  3:02                                 ` David Gibson
     [not found]                                 ` <20110812030218.GP30552-787xzQ0H9iQXU02nzanrWNbf9cGiqdzd@public.gmane.org>
2011-08-12  8:14                                   ` Cousson, Benoit
2011-08-12  8:14                                     ` Cousson, Benoit
2011-08-12  8:41                                 ` Felipe Balbi
2011-08-12  8:41                                   ` Felipe Balbi
     [not found]                                   ` <20110812084106.GC19467-UiBtZHVXSwEVvW8u9ZQWYwjfymiNCTlR@public.gmane.org>
2011-08-12 14:35                                     ` Arnd Bergmann
2011-08-12 14:35                                       ` Arnd Bergmann
2011-08-12 15:09                                       ` Cousson, Benoit
2011-08-12 15:09                                         ` Cousson, Benoit
2011-08-12 17:21                                         ` Grant Likely
2011-08-12 17:21                                           ` Grant Likely
2011-08-24 19:15                                           ` Kevin Hilman
2011-08-24 19:15                                             ` Kevin Hilman
2011-08-24 23:16                                             ` Felipe Balbi
2011-08-24 23:16                                               ` Felipe Balbi
     [not found]                                               ` <20110824231613.GC19890-UiBtZHVXSwEVvW8u9ZQWYwjfymiNCTlR@public.gmane.org>
2011-08-25 10:28                                                 ` Russell King - ARM Linux
2011-08-25 10:28                                                   ` Russell King - ARM Linux
     [not found]                                                   ` <20110825102824.GB10405-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2011-08-25 15:05                                                     ` Arnd Bergmann
2011-08-25 15:05                                                       ` Arnd Bergmann
2011-08-25 18:16                                                       ` Kevin Hilman
2011-08-25 18:16                                                         ` Kevin Hilman
2011-08-25 21:02                                                         ` Arnd Bergmann
2011-08-25 21:02                                                           ` Arnd Bergmann
2011-08-26 11:01                                                           ` Removing platform_get_resource_byname() (was Re: How to handle named resources with DT?) Paul Walmsley
2011-08-26 11:01                                                             ` Paul Walmsley
2011-08-26 11:01                                                             ` Paul Walmsley
2011-08-26  4:12                                                         ` How to handle named resources with DT? David Gibson
2011-08-26  4:12                                                           ` David Gibson
     [not found]                                                           ` <20110826041200.GD2308-787xzQ0H9iQXU02nzanrWNbf9cGiqdzd@public.gmane.org>
2011-08-26 10:58                                                             ` Arnd Bergmann
2011-08-26 10:58                                                               ` Arnd Bergmann
2011-08-26 13:06                                                               ` David Gibson
2011-08-26 13:06                                                                 ` David Gibson
2011-08-26 15:35                                                                 ` Arnd Bergmann
2011-08-26 15:35                                                                   ` Arnd Bergmann
     [not found]                                                                   ` <201108261735.55412.arnd-r2nGTMty4D4@public.gmane.org>
2011-08-26 15:41                                                                     ` Arnd Bergmann
2011-08-26 15:41                                                                       ` Arnd Bergmann
2011-08-27 14:37                                                                       ` David Gibson
2011-08-27 14:37                                                                         ` David Gibson
2011-08-27 18:13                                                                         ` Arnd Bergmann
2011-08-27 18:13                                                                           ` Arnd Bergmann
2011-08-27 19:31                                                                           ` Paul Walmsley
2011-08-27 19:31                                                                             ` Paul Walmsley
2011-08-29 17:16                                                                             ` Arnd Bergmann
2011-08-29 17:16                                                                               ` Arnd Bergmann
2011-08-28  8:39                                                                           ` David Gibson
2011-08-28  8:39                                                                             ` David Gibson
2011-08-28 23:06                                                                             ` Paul Walmsley
2011-08-28 23:06                                                                               ` Paul Walmsley
     [not found]                                                                               ` <alpine.DEB.2.00.1108281100150.23968-rwI8Ez+7Ko+d5PgPZx9QOdBPR1lH4CV8@public.gmane.org>
2011-08-28 23:43                                                                                 ` Russell King - ARM Linux
2011-08-28 23:43                                                                                   ` Russell King - ARM Linux
2011-08-29  1:57                                                                               ` Paul Walmsley
2011-08-29  1:57                                                                                 ` Paul Walmsley
2011-08-29 17:18                                                                             ` Arnd Bergmann
2011-08-29 17:18                                                                               ` Arnd Bergmann
2011-08-27 21:47                                                                 ` Paul Walmsley
2011-08-27 21:47                                                                   ` Paul Walmsley
     [not found]                                                                   ` <alpine.DEB.2.00.1108271444240.23968-rwI8Ez+7Ko+d5PgPZx9QOdBPR1lH4CV8@public.gmane.org>
2011-08-29 21:54                                                                     ` Mark Brown
2011-08-29 21:54                                                                       ` Mark Brown
2011-08-26 14:13                                                               ` Cousson, Benoit
2011-08-26 14:13                                                                 ` Cousson, Benoit
2011-08-30  2:29                                                                 ` David Gibson
2011-08-30  2:29                                                                   ` David Gibson
2011-08-30  9:27                                                                   ` Felipe Balbi
2011-08-30  9:27                                                                     ` Felipe Balbi
     [not found]                                                                     ` <20110830092722.GG23907-UiBtZHVXSwEVvW8u9ZQWYwjfymiNCTlR@public.gmane.org>
2011-08-31  2:32                                                                       ` David Gibson
2011-08-31  2:32                                                                         ` David Gibson
2011-08-27 20:00                                                               ` Paul Walmsley
2011-08-27 20:00                                                                 ` Paul Walmsley
2011-08-25 17:38                                                   ` Cousson, Benoit
2011-08-25 17:38                                                     ` Cousson, Benoit
2011-08-09 21:52                     ` Scott Wood
2011-08-09 21:52                       ` Scott Wood
2011-08-09 20:55         ` Grant Likely
2011-08-09 20:55           ` Grant Likely
2011-08-09 21:06           ` Cousson, Benoit
2011-08-09 21:06             ` Cousson, Benoit
2011-08-09 21:16             ` Grant Likely
2011-08-09 21:16               ` Grant Likely
2011-08-09 21:37               ` Cousson, Benoit
2011-08-09 21:37                 ` Cousson, Benoit
2011-08-12  4:10                 ` Shawn Guo
2011-08-12  4:10                   ` Shawn Guo
2011-08-12  8:56                   ` Cousson, Benoit
2011-08-12  8:56                     ` Cousson, Benoit
2011-08-12 11:47                     ` Shawn Guo
2011-08-12 11:47                       ` Shawn Guo
2011-08-12 14:40                     ` Arnd Bergmann
2011-08-12 14:40                       ` Arnd Bergmann
2011-08-10  1:29       ` David Gibson
2011-08-10  1:29         ` David Gibson
2011-08-10  6:08         ` Paul Walmsley
2011-08-10  6:08           ` Paul Walmsley
2011-08-09 19:51 ` Russell King - ARM Linux
2011-08-09 19:51   ` Russell King - ARM Linux
2011-08-09 20:59   ` Cousson, Benoit
2011-08-09 20:59     ` Cousson, Benoit

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