* i2c keyboard
@ 2009-02-23 8:50 Oleg Kravchenko
2009-02-23 11:05 ` Marek Vasut
0 siblings, 1 reply; 2+ messages in thread
From: Oleg Kravchenko @ 2009-02-23 8:50 UTC (permalink / raw)
To: linux-input
Hello, everyone.
We are porting the Linux kernel to our PDA, Asus P525/P535. This device
has a pca9535 gpio extender. The keyboard is connected to it. The
extender has only one irq. At the moment, the pca9535 is handled by
pca953x gpio driver. We need to have the access to its registers from
our keyboard driver (so as not to read 13 gpios, but decode the register
containing gpio states). If i try to read each of these 13 gpios after
the interrupt from the extender comes, the kernel crashes. Is there a
solution to read i2c client addresses when there is a client registered
already?
http://www.kaa.org.ua/asus-p535/hardware.html
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: i2c keyboard
2009-02-23 8:50 i2c keyboard Oleg Kravchenko
@ 2009-02-23 11:05 ` Marek Vasut
0 siblings, 0 replies; 2+ messages in thread
From: Marek Vasut @ 2009-02-23 11:05 UTC (permalink / raw)
To: Oleg Kravchenko; +Cc: linux-input
On Monday 23 of February 2009 09:50:52 Oleg Kravchenko wrote:
> Hello, everyone.
> We are porting the Linux kernel to our PDA, Asus P525/P535. This device
> has a pca9535 gpio extender. The keyboard is connected to it. The
> extender has only one irq. At the moment, the pca9535 is handled by
> pca953x gpio driver. We need to have the access to its registers from
> our keyboard driver (so as not to read 13 gpios, but decode the register
> containing gpio states). If i try to read each of these 13 gpios after
> the interrupt from the extender comes, the kernel crashes. Is there a
> solution to read i2c client addresses when there is a client registered
> already?
>
There was some discussion about implementing batch GPIO reads in
linux-arm-kernel mailing list, that's probably what you want.
>
> http://www.kaa.org.ua/asus-p535/hardware.html
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