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From: thierry.reding@gmail.com (Thierry Reding)
To: linux-arm-kernel@lists.infradead.org
Subject: ARM topic: Is DT on ARM the solution, or is there something better?
Date: Mon, 18 Nov 2013 16:29:21 +0100	[thread overview]
Message-ID: <20131118152920.GL26046@ulmo.nvidia.com> (raw)
In-Reply-To: <20131118135727.GD14306@sirena.org.uk>

On Mon, Nov 18, 2013 at 01:57:27PM +0000, Mark Brown wrote:
> On Mon, Nov 18, 2013 at 01:40:22PM +0000, Grant Likely wrote:
> 
> > Some hardware does that. That's what OHCI, EHCI, UHCI, XHCI, SDHCI, and
> > similar are all about. It always helps when well understood hardware
> > follows a register interface. It doesn't work for everything, but I
> > agree it would be good to have preferred hw interfaces for SPI & I2C.
> 
> You'd need something class based like USB, there's such massive
> variation in what the hardware is trying to do and the tradeoffs.  A big
> issue is that especially with I2C many of the devices are primarily
> analogue devices implemnted in larger processes where the cost of adding
> additional digital logic can have a noticeable effect on the area and
> hence cost of the silicon.

My comments were mostly regarding the interface controllers. Those which
generate the same bus transactions but need different drivers on every
SoC. I suspect that the same costs don't apply (or at least not to the
same extent) to SoCs.

Thierry
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WARNING: multiple messages have this Message-ID (diff)
From: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Grant Likely
	<grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>,
	Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>,
	"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"ksummit-2013-discuss-cunTk1MwBs98uUxBSJOaYoYkZiVZrdSR2LY78lusg7I@public.gmane.org"
	<ksummit-2013-discuss-cunTk1MwBs98uUxBSJOaYoYkZiVZrdSR2LY78lusg7I@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: ARM topic: Is DT on ARM the solution, or is there something better?
Date: Mon, 18 Nov 2013 16:29:21 +0100	[thread overview]
Message-ID: <20131118152920.GL26046@ulmo.nvidia.com> (raw)
In-Reply-To: <20131118135727.GD14306-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>

[-- Attachment #1: Type: text/plain, Size: 1080 bytes --]

On Mon, Nov 18, 2013 at 01:57:27PM +0000, Mark Brown wrote:
> On Mon, Nov 18, 2013 at 01:40:22PM +0000, Grant Likely wrote:
> 
> > Some hardware does that. That's what OHCI, EHCI, UHCI, XHCI, SDHCI, and
> > similar are all about. It always helps when well understood hardware
> > follows a register interface. It doesn't work for everything, but I
> > agree it would be good to have preferred hw interfaces for SPI & I2C.
> 
> You'd need something class based like USB, there's such massive
> variation in what the hardware is trying to do and the tradeoffs.  A big
> issue is that especially with I2C many of the devices are primarily
> analogue devices implemnted in larger processes where the cost of adding
> additional digital logic can have a noticeable effect on the area and
> hence cost of the silicon.

My comments were mostly regarding the interface controllers. Those which
generate the same bus transactions but need different drivers on every
SoC. I suspect that the same costs don't apply (or at least not to the
same extent) to SoCs.

Thierry

[-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --]

  reply	other threads:[~2013-11-18 15:29 UTC|newest]

Thread overview: 342+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-20 21:26 ARM topic: Is DT on ARM the solution, or is there something better? Stephen Warren
2013-10-20 21:26 ` Stephen Warren
2013-10-20 22:08 ` [Ksummit-2013-discuss] " Mark Brown
2013-10-20 22:08   ` Mark Brown
2013-10-20 22:21   ` Stephen Warren
2013-10-20 22:21     ` Stephen Warren
2013-10-21  1:00     ` Nicolas Pitre
2013-10-21  1:00       ` Nicolas Pitre
2013-10-21  9:15       ` Thierry Reding
2013-10-21  9:15         ` Thierry Reding
2013-10-21 14:57         ` Maxime Bizon
2013-10-21 14:57           ` Maxime Bizon
2013-10-21 17:07         ` Richard Cochran
2013-10-21 17:07           ` Richard Cochran
2013-10-21 20:24           ` Stephen Warren
2013-10-21 20:24             ` Stephen Warren
2013-10-22  9:24           ` Thierry Reding
2013-10-22  9:24             ` Thierry Reding
2013-10-23 17:30             ` Richard Cochran
2013-10-23 17:30               ` Richard Cochran
2013-10-23 19:06               ` Thierry Reding
2013-10-23 19:06                 ` Thierry Reding
2013-10-22 17:22           ` Jason Gunthorpe
2013-10-22 17:22             ` Jason Gunthorpe
2013-10-21 20:29       ` Stephen Warren
2013-10-21 20:29         ` Stephen Warren
2013-10-21 20:40         ` Nicolas Pitre
2013-10-21 20:40           ` Nicolas Pitre
2013-10-22  9:39           ` Thierry Reding
2013-10-22  9:39             ` Thierry Reding
2013-10-22 15:04             ` Matt Porter
2013-10-22 15:04               ` Matt Porter
2013-10-22 17:13               ` Jason Gunthorpe
2013-10-22 17:13                 ` Jason Gunthorpe
2013-10-22 17:49                 ` Guenter Roeck
2013-10-22 17:49                   ` Guenter Roeck
2013-10-23  8:06                 ` Richard Cochran
2013-10-23  8:06                   ` Richard Cochran
2013-10-23  9:49                   ` Thierry Reding
2013-10-23  9:49                     ` Thierry Reding
2013-10-23 17:16                     ` Richard Cochran
2013-10-23 17:16                       ` Richard Cochran
2013-10-23 17:25                       ` Matt Porter
2013-10-23 17:25                         ` Matt Porter
2013-10-23 18:05                         ` Richard Cochran
2013-10-23 18:05                           ` Richard Cochran
2013-10-23 18:57                           ` Nicolas Pitre
2013-10-23 18:57                             ` Nicolas Pitre
2013-10-23 20:12                           ` Matt Porter
2013-10-23 20:12                             ` Matt Porter
2013-10-23 17:55                       ` Nicolas Pitre
2013-10-23 17:55                         ` Nicolas Pitre
2013-10-23 18:13                         ` Richard Cochran
2013-10-23 18:13                           ` Richard Cochran
2013-10-23 20:35                           ` Thierry Reding
2013-10-23 20:35                             ` Thierry Reding
2013-10-23 17:29                   ` Jason Gunthorpe
2013-10-23 17:29                     ` Jason Gunthorpe
2013-10-23 17:45                     ` Richard Cochran
2013-10-23 17:45                       ` Richard Cochran
2013-10-23 18:46                       ` Maxime Bizon
2013-10-23 18:46                         ` Maxime Bizon
2013-10-23 18:51                         ` Richard Cochran
2013-10-23 18:51                           ` Richard Cochran
2013-10-23 19:12                           ` Maxime Bizon
2013-10-23 19:12                             ` Maxime Bizon
2013-10-24  9:52                         ` Grant Likely
2013-10-24  9:52                           ` Grant Likely
2013-10-24 11:33                           ` Maxime Bizon
2013-10-24 11:33                             ` Maxime Bizon
2013-10-24 11:47                             ` David Woodhouse
2013-10-24 11:47                               ` David Woodhouse
2013-10-24 12:13                               ` Maxime Bizon
2013-10-24 12:13                                 ` Maxime Bizon
2013-10-24 12:22                                 ` David Woodhouse
2013-10-24 12:22                                   ` David Woodhouse
2013-10-24 12:22                                 ` David Woodhouse
2013-10-24 12:22                                   ` David Woodhouse
2013-10-24 13:05                                   ` Maxime Bizon
2013-10-24 13:05                                     ` Maxime Bizon
2013-10-24 13:14                                     ` David Woodhouse
2013-10-24 13:14                                       ` David Woodhouse
2013-10-24 13:46                                       ` Maxime Bizon
2013-10-24 13:46                                         ` Maxime Bizon
2013-10-24 19:52                                         ` Matt Porter
2013-10-24 19:52                                           ` Matt Porter
2013-10-24 20:11                                       ` Matt Sealey
2013-10-24 20:11                                         ` Matt Sealey
2013-10-25  9:00                                 ` Stephen Warren
2013-10-25  9:00                                   ` Stephen Warren
2013-10-24 12:23                               ` Thierry Reding
2013-10-24 12:23                                 ` Thierry Reding
2013-10-24 12:29                                 ` David Woodhouse
2013-10-24 12:29                                   ` David Woodhouse
2013-10-24 13:00                                 ` Maxime Bizon
2013-10-24 13:00                                   ` Maxime Bizon
2013-10-24 13:10                                   ` David Woodhouse
2013-10-24 13:10                                     ` David Woodhouse
2013-10-24 13:30                                     ` Maxime Bizon
2013-10-24 13:30                                       ` Maxime Bizon
2013-10-24 14:05                                       ` David Woodhouse
2013-10-24 14:05                                         ` David Woodhouse
2013-10-24 14:19                                         ` Thierry Reding
2013-10-24 14:19                                           ` Thierry Reding
2013-10-24 14:30                                           ` David Woodhouse
2013-10-24 14:30                                             ` David Woodhouse
2013-10-24 14:38                                             ` Thierry Reding
2013-10-24 14:38                                               ` Thierry Reding
2013-10-24 16:39                                             ` Nicolas Pitre
2013-10-24 16:39                                               ` Nicolas Pitre
2013-10-24 16:45                                               ` David Woodhouse
2013-10-24 16:45                                                 ` David Woodhouse
2013-10-24 17:08                                                 ` Nicolas Pitre
2013-10-24 17:08                                                   ` Nicolas Pitre
2013-10-24 18:15                                                 ` jonsmirl at gmail.com
2013-10-24 18:15                                                   ` jonsmirl-Re5JQEeQqe8AvxtiuMwx3w
2013-10-24 14:32                                           ` Richard Cochran
2013-10-24 14:32                                             ` Richard Cochran
2013-10-24 14:47                                             ` Thierry Reding
2013-10-24 14:47                                               ` Thierry Reding
2013-10-24 15:37                                             ` Nicolas Pitre
2013-10-24 15:37                                               ` Nicolas Pitre
2013-10-24 14:33                                           ` Maxime Bizon
2013-10-24 14:33                                             ` Maxime Bizon
2013-10-24 14:57                                             ` Thierry Reding
2013-10-24 14:57                                               ` Thierry Reding
2013-10-24 16:27                                         ` Nicolas Pitre
2013-10-24 16:27                                           ` Nicolas Pitre
2013-10-24 14:12                                     ` Thierry Reding
2013-10-24 14:12                                       ` Thierry Reding
2013-10-24 14:22                                       ` David Woodhouse
2013-10-24 14:22                                         ` David Woodhouse
2013-10-24 14:23                                         ` Thierry Reding
2013-10-24 14:23                                           ` Thierry Reding
2013-10-24 14:38                                           ` David Woodhouse
2013-10-24 14:38                                             ` David Woodhouse
2013-10-24 14:58                                             ` Thierry Reding
2013-10-24 14:58                                               ` Thierry Reding
2013-10-24 19:58                                         ` Matt Porter
2013-10-24 19:58                                           ` Matt Porter
2013-10-24 23:54                                       ` Grant Likely
2013-10-24 23:54                                         ` Grant Likely
2013-10-25  8:52                             ` Stephen Warren
2013-10-25  8:52                               ` Stephen Warren
2013-10-25  9:16                               ` Thierry Reding
2013-10-25  9:16                                 ` Thierry Reding
2013-10-23 17:47                     ` Richard Cochran
2013-10-23 17:47                       ` Richard Cochran
2013-10-23 17:58                       ` Nicolas Pitre
2013-10-23 17:58                         ` Nicolas Pitre
2013-10-23 18:02                       ` Jason Gunthorpe
2013-10-23 18:02                         ` Jason Gunthorpe
2013-10-23 18:23                         ` Richard Cochran
2013-10-23 18:23                           ` Richard Cochran
2013-10-24  8:34                           ` Thierry Reding
2013-10-24  8:34                             ` Thierry Reding
2013-10-24 15:00                             ` Richard Cochran
2013-10-24 15:00                               ` Richard Cochran
2013-10-24 19:46                               ` Matt Porter
2013-10-24 19:46                                 ` Matt Porter
2013-10-23 18:01                     ` Guenter Roeck
2013-10-23 18:01                       ` Guenter Roeck
2013-10-23 18:25                       ` Jason Gunthorpe
2013-10-23 18:25                         ` Jason Gunthorpe
2013-10-23 18:30                         ` Richard Cochran
2013-10-23 18:30                           ` Richard Cochran
2013-10-23 18:54                           ` Jason Gunthorpe
2013-10-23 18:54                             ` Jason Gunthorpe
2013-10-24  8:06                             ` Sascha Hauer
2013-10-24  8:06                               ` Sascha Hauer
2013-10-24  8:17                               ` Thierry Reding
2013-10-24  8:17                                 ` Thierry Reding
2013-10-24  8:52                                 ` Sascha Hauer
2013-10-24  8:52                                   ` Sascha Hauer
2013-10-23 23:29                           ` Ben Hutchings
2013-10-23 23:29                             ` Ben Hutchings
2013-10-24  7:32                             ` Richard Cochran
2013-10-24  7:32                               ` Richard Cochran
2013-10-24  9:35                               ` Ben Hutchings
2013-10-24  9:35                                 ` Ben Hutchings
2013-10-24 12:02                         ` Andre Heider
2013-10-24 12:02                           ` Andre Heider
2013-10-24  8:01                     ` Sascha Hauer
2013-10-24  8:01                       ` Sascha Hauer
2013-10-24  8:11                       ` Thierry Reding
2013-10-24  8:11                         ` Thierry Reding
2013-10-22 17:42               ` Nicolas Pitre
2013-10-22 17:42                 ` Nicolas Pitre
2013-10-22 18:21                 ` Peter Maydell
2013-10-22 18:21                   ` Peter Maydell
2013-10-22 18:36                   ` Nicolas Pitre
2013-10-22 18:36                     ` Nicolas Pitre
2013-10-22 19:16                   ` Guenter Roeck
2013-10-22 19:16                     ` Guenter Roeck
2013-10-22 20:12                 ` Thierry Reding
2013-10-22 20:12                   ` Thierry Reding
2013-10-22 20:41                   ` Nicolas Pitre
2013-10-22 20:41                     ` Nicolas Pitre
2013-10-22 21:39                     ` Jason Gunthorpe
2013-10-22 21:39                       ` Jason Gunthorpe
2013-10-23  8:50                     ` Thierry Reding
2013-10-23  8:50                       ` Thierry Reding
2013-10-23  9:02                     ` Thierry Reding
2013-10-23  9:02                       ` Thierry Reding
2013-10-22 20:42                   ` Matt Porter
2013-10-22 20:42                     ` Matt Porter
2013-10-23 10:04                     ` Thierry Reding
2013-10-23 10:04                       ` Thierry Reding
2013-10-23 11:48                       ` Peter Maydell
2013-10-23 11:48                         ` Peter Maydell
2013-10-23 16:29                       ` Matt Porter
2013-10-23 16:29                         ` Matt Porter
2013-10-22  6:47       ` David Brown
2013-10-22  6:47         ` David Brown
2013-10-20 23:11 ` Russell King - ARM Linux
2013-10-20 23:11   ` Russell King - ARM Linux
2013-10-20 23:44   ` [Ksummit-2013-discuss] " Guenter Roeck
2013-10-20 23:44     ` Guenter Roeck
2013-10-20 23:51     ` Russell King - ARM Linux
2013-10-20 23:51       ` Russell King - ARM Linux
2013-10-21  0:13       ` Guenter Roeck
2013-10-21  0:13         ` Guenter Roeck
2013-10-21 20:05     ` Stephen Warren
2013-10-21 20:05       ` Stephen Warren
2013-10-22  9:45       ` Thierry Reding
2013-10-22  9:45         ` Thierry Reding
2013-10-21  8:32   ` Sascha Hauer
2013-10-21  8:32     ` Sascha Hauer
2013-10-21  8:48     ` Russell King - ARM Linux
2013-10-21  8:48       ` Russell King - ARM Linux
2013-10-21  9:27       ` Sascha Hauer
2013-10-21  9:27         ` Sascha Hauer
     [not found]         ` < CAF6AEGtt_2sStiZCNBp9btxevWghSwLZZBdN6ir8eUpX1FXrCQ@mail.gmail.com>
     [not found]           ` < 20131024072811.GS30088@pengutronix.de>
     [not found]             ` < CAF6AEGuEho9Ms7ifTE-EmBoQ-=_AXgvGcJxi5qEC0vsZ+H9C+A@mail.gmail.com>
2013-10-21  9:57         ` Russell King - ARM Linux
2013-10-21  9:57           ` Russell King - ARM Linux
2013-10-21 10:24           ` Thierry Reding
2013-10-21 10:24             ` Thierry Reding
2013-10-21 10:30             ` Russell King - ARM Linux
2013-10-21 10:30               ` Russell King - ARM Linux
2013-10-21 10:41               ` Thierry Reding
2013-10-21 10:41                 ` Thierry Reding
2013-10-22  9:19             ` [Ksummit-2013-discuss] " Mark Brown
2013-10-22  9:19               ` Mark Brown
2013-10-21 20:09           ` Stephen Warren
2013-10-21 20:09             ` Stephen Warren
2013-10-21 23:18           ` Sascha Hauer
2013-10-21 23:18             ` Sascha Hauer
2013-10-24  1:14         ` Rob Clark
2013-10-24  1:14           ` Rob Clark
2013-10-24  7:28           ` Sascha Hauer
2013-10-24  7:28             ` Sascha Hauer
2013-10-24  9:00             ` Thierry Reding
2013-10-24  9:00               ` Thierry Reding
2013-10-24  9:21               ` Sascha Hauer
2013-10-24  9:21                 ` Sascha Hauer
2013-10-24 21:21             ` Rob Clark
2013-10-24 21:21               ` Rob Clark
2013-10-25  9:24               ` Thierry Reding
2013-10-25  9:24                 ` Thierry Reding
2013-11-18 12:45               ` Russell King - ARM Linux
2013-11-18 12:45                 ` Russell King - ARM Linux
2013-11-18 15:37                 ` Thierry Reding
2013-11-18 15:37                   ` Thierry Reding
2013-11-18 16:11                   ` Russell King - ARM Linux
2013-11-18 16:11                     ` Russell King - ARM Linux
2013-11-18 16:18                     ` Thierry Reding
2013-11-18 16:18                       ` Thierry Reding
2013-11-18 18:43                     ` Mark Brown
2013-11-18 18:43                       ` Mark Brown
2013-11-19 13:54                 ` Grant Likely
2013-11-19 13:54                   ` Grant Likely
2013-10-21 10:04       ` Thierry Reding
2013-10-21 10:04         ` Thierry Reding
2013-10-21 10:57       ` [Ksummit-2013-discuss] " Laurent Pinchart
2013-10-21 10:57         ` Laurent Pinchart
2013-10-21 10:00   ` Laurent Pinchart
2013-10-21 10:00     ` Laurent Pinchart
2013-10-21 11:18   ` Sebastian Hesselbarth
2013-10-21 11:18     ` Sebastian Hesselbarth
2013-10-21  8:54 ` Thierry Reding
2013-10-21  8:54   ` Thierry Reding
2013-10-21 20:19   ` Stephen Warren
2013-10-21 20:19     ` Stephen Warren
2013-10-21 22:51     ` [Ksummit-2013-discuss] " Guenter Roeck
2013-10-21 22:51       ` Guenter Roeck
2013-10-22 10:27       ` James Hogan
2013-10-22 10:27         ` James Hogan
2013-10-22 16:31         ` Jonathan Cameron
2013-10-22 16:31           ` Jonathan Cameron
2013-10-22 16:49           ` Guenter Roeck
2013-10-22 16:49             ` Guenter Roeck
2013-10-22 20:35             ` Thierry Reding
2013-10-22 20:35               ` Thierry Reding
2013-10-22 21:10               ` Guenter Roeck
2013-10-22 21:10                 ` Guenter Roeck
2013-10-23  7:57                 ` Thierry Reding
2013-10-23  7:57                   ` Thierry Reding
2013-10-23 16:01                   ` Guenter Roeck
2013-10-23 16:01                     ` Guenter Roeck
2013-10-23 21:07                     ` Thierry Reding
2013-10-23 21:07                       ` Thierry Reding
2013-10-24 15:18                       ` Guenter Roeck
2013-10-24 15:18                         ` Guenter Roeck
2013-11-01 10:36                         ` Thierry Reding
2013-11-01 10:36                           ` Thierry Reding
2013-11-01 13:30                           ` Guenter Roeck
2013-11-01 13:30                             ` Guenter Roeck
2013-10-22 20:48         ` Thierry Reding
2013-10-22 20:48           ` Thierry Reding
2013-10-22 10:25     ` Thierry Reding
2013-10-22 10:25       ` Thierry Reding
2013-10-22 21:44 ` Matt Sealey
2013-10-22 21:44   ` Matt Sealey
2013-10-23 11:41   ` Peter Maydell
2013-10-23 11:41     ` Peter Maydell
2013-10-23 23:02     ` [Ksummit-2013-discuss] " Rob Herring
2013-10-23 23:02       ` Rob Herring
2013-11-18 12:26 ` Thierry Reding
2013-11-18 12:26   ` Thierry Reding
2013-11-18 13:40   ` Grant Likely
2013-11-18 13:40     ` Grant Likely
2013-11-18 13:57     ` Mark Brown
2013-11-18 13:57       ` Mark Brown
2013-11-18 15:29       ` Thierry Reding [this message]
2013-11-18 15:29         ` Thierry Reding
2013-11-18 15:50         ` Mark Brown
2013-11-18 15:50           ` Mark Brown
2013-11-18 16:06           ` Thierry Reding
2013-11-18 16:06             ` Thierry Reding
2013-11-18 17:16             ` Stephen Warren
2013-11-18 17:16               ` Stephen Warren
2013-11-19  9:35               ` Thierry Reding
2013-11-19  9:35                 ` Thierry Reding
2013-11-19 17:27                 ` Stephen Warren
2013-11-19 17:27                   ` Stephen Warren
2013-11-20 13:29                   ` Thierry Reding
2013-11-20 13:29                     ` Thierry Reding
2013-11-18 18:35             ` Mark Brown
2013-11-18 18:35               ` Mark Brown
2013-11-19  9:11               ` Thierry Reding
2013-11-19  9:11                 ` Thierry Reding
2013-11-19 10:16                 ` Mark Brown
2013-11-19 10:16                   ` Mark Brown

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