Access 16bits address register in a device through I2C

Access 16bits address register in a device through I2C

[Wen Wang]

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Hi all,
I have a problem writing an I2C device driver and would greatly appreciate
if someone could provide some enlightenment.

I'm working on a project needs to access registers with 16bits address
through I2C. But unfortunately I can not find a way to achieve this, cause
it seems that current kernel I2C framework only supports 8bits address
register.

So I'm wondering do I miss something or what can I do? Any ideas?

Thanks
Wen

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Re: Access 16bits address register in a device through I2C

[Ben Dooks]

On Fri, Jul 18, 2008 at 12:13:30AM +0800, Wen Wang wrote:
> Hi all,
> I have a problem writing an I2C device driver and would greatly appreciate
> if someone could provide some enlightenment.
> 
> I'm working on a project needs to access registers with 16bits address
> through I2C. But unfortunately I can not find a way to achieve this, cause
> it seems that current kernel I2C framework only supports 8bits address
> register.

The easiest way is to create a function that uses a pair of i2c messages,
the first message sends the 16bits of address pointer to the device, the
second one either reads or writes data.
 
> So I'm wondering do I miss something or what can I do? Any ideas?
> 
> Thanks
> Wen

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> i2c mailing list
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-- 
Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

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Re: Access 16bits address register in a device through I2C

[Wolfram Sang]

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Hi Wen,

On Fri, Jul 18, 2008 at 12:13:30AM +0800, Wen Wang wrote:

> So I'm wondering do I miss something or what can I do? Any ideas?

For an example what Ben suggested (2 messages), have a look at the
at24-driver, which just went through the merge-window.

http://article.gmane.org/gmane.linux.drivers.i2c/1661

Check functions 'at24_eeprom_[read|write]' for details.

All the best,

   Wolfram

-- 
  Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry

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Re: Access 16bits address register in a device through I2C

[Wen Wang]

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Hi Guys,

Thank you for your kindly heads up, that really helps me a lot :)

BRs
Wen

On Fri, Jul 18, 2008 at 1:06 AM, Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:

> Hi Wen,
>
> On Fri, Jul 18, 2008 at 12:13:30AM +0800, Wen Wang wrote:
>
> > So I'm wondering do I miss something or what can I do? Any ideas?
>
> For an example what Ben suggested (2 messages), have a look at the
> at24-driver, which just went through the merge-window.
>
> http://article.gmane.org/gmane.linux.drivers.i2c/1661
>
> Check functions 'at24_eeprom_[read|write]' for details.
>
> All the best,
>
>   Wolfram
>
> --
>  Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
>  Pengutronix - Linux Solutions for Science and Industry
>
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