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From: Timur Tabi <timur@freescale.com>
To: Olof Johansson <olof@lixom.net>
Cc: linuxppc-dev@ozlabs.org, sl@powerlinux.fr,
	Philippe Lachenal <philippe.lachenal@hotmail.fr>
Subject: Re: MPC8349ea Random Device Generator driver
Date: Thu, 07 Jun 2007 10:20:19 -0500	[thread overview]
Message-ID: <46682233.7060601@freescale.com> (raw)
In-Reply-To: <20070607152041.GA2851@lixom.net>

Olof Johansson wrote:

> No. in_le16 exists so you can read a little-endian 16 bit register on
> a device, and store it to a regular 16-bit integer variable. It
> has nothing to do with assignment.

What?  Reading from a register and storing the value into a variable *is* assignment.  If 
I have code like this:

	A = B;

I'm assigning B to A.

For the record, I understand the concepts you're talking about, I'm only confused about 
about some of things I'm reading.

> __le16 is just a type with hints for the programmer: "Hey, this is a
> 16-bit variable, but we're storing it in little-endian format. So if you
> need to use it as a native data type, you need to swap it by hand first",
> and sparse is able to help you find places where you didn't.

I understand that.

> If you use the accessors to read/write hardware (as you are supposed to
> do), then you don't need special types in your structs, just make sure
> you use the right accessors.

Ok, I understand that, too.  I just don't understand absolutist statements like "you can 
never assign a __le16 type to any other integer type" when our code is full of example of 
doing just that.

-- 
Timur Tabi
Linux Kernel Developer @ Freescale

  reply	other threads:[~2007-06-07 15:20 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-05 15:42 MPC8349ea Random Device Generator driver Philippe Lachenal
2007-06-06 14:15 ` Arnd Bergmann
2007-06-07 11:29   ` MPC8349ea Random Number " Philippe Lachenal
2007-06-07 14:03     ` Arnd Bergmann
2007-06-06 21:57 ` MPC8349ea Random Device " Timur Tabi
2007-06-06 22:09   ` Olof Johansson
2007-06-06 22:07     ` Timur Tabi
2007-06-06 22:11       ` Arnd Bergmann
2007-06-06 22:19         ` Timur Tabi
2007-06-06 22:35           ` Arnd Bergmann
2007-06-06 22:38             ` Timur Tabi
2007-06-06 22:24       ` Olof Johansson
2007-06-06 22:32         ` Timur Tabi
2007-06-06 23:54           ` Olof Johansson
2007-06-07 14:23             ` Timur Tabi
2007-06-07 15:20               ` Olof Johansson
2007-06-07 15:20                 ` Timur Tabi [this message]
2007-06-07 15:36                   ` Olof Johansson
2007-06-06 22:48         ` Timur Tabi
2007-06-07  0:00           ` Olof Johansson
2007-06-07  2:55 ` Kim Phillips

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