From: voice.shen@atmel•com (Bo Shen)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] i2c: change the id to let the i2c device work
Date: Fri, 12 Oct 2012 13:45:48 +0800 [thread overview]
Message-ID: <5077AE8C.5040605@atmel.com> (raw)
In-Reply-To: <20121012051419.GJ11726@opensource.wolfsonmicro.com>
On 10/12/2012 13:14, Mark Brown wrote:
> On Fri, Oct 12, 2012 at 12:57:34PM +0800, Bo Shen wrote:
>> On 10/12/2012 12:40, Mark Brown wrote:
>>> On Fri, Oct 12, 2012 at 10:34:18AM +0800, Bo Shen wrote:
>
>>>> As the old method will use platform device id, change the id to
>>>> let the i2c device work
>
>>> What are "the old method" and new method? You're not explaining why
>>> this is needed...
>
>> Maybe use the 'legacy method' will be better (I am not sure). Now,
>> the Linux kernel is transferring to device tree which doesn't use
>> platform device id. So, change the id to let the legacy code work.
>
>> May you understand.
>
> No, this still makes no sense to me. This is clearly a non-DT device
> registration, what does DT have to do with anything here? What is the
Yes, this is non-DT device registration.
As the Linux kernel code is transferring to DT which doesn't use
platform device id. however here, modified unconsciously. So correct
this error.
> practical problem you are seeing in your system and how does this help
> with it?
In non-DT kernel, we use platform device id to distinguish between each
device.
For example,
if register i2c device on i2c bus 0, using:
i2c_register_board_info(0, ...)
if register i2c device on i2c bus 1, using:
i2c_register_board_info(1, ...)
So, in this case, if the id = -1, i2c core will dynamically assign a bus
id to this bus when running, the dynamically assigned bus id is unknown
when writing the code. So, when we use i2c_register_board_info(int
busnum, ...) to register device on busnum. we don't know which value to
be use.
So, this patch will fix this issue.
BRs,
Bo Shen
next prev parent reply other threads:[~2012-10-12 5:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-12 2:34 [PATCH] i2c: change the id to let the i2c device work Bo Shen
2012-10-12 4:40 ` Mark Brown
2012-10-12 4:57 ` Bo Shen
2012-10-12 5:14 ` Mark Brown
2012-10-12 5:45 ` Bo Shen [this message]
2012-10-12 5:53 ` Mark Brown
2012-10-12 6:42 ` Bo Shen
2012-10-12 7:14 ` Jean Delvare
2012-10-12 7:55 ` Bo Shen
2012-10-12 8:05 ` Jean Delvare
2012-10-12 8:21 ` Mark Brown
2012-10-12 9:02 ` Bo Shen
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