Hi again,
On Thu, Feb 02, 2012 at 11:49:08PM +0200, Felipe Balbi wrote:
> > In fact the driver already handled the 6 GPIOS banks as individual devices:
> >
> > [ 0.185638] gpiochip_add: registered GPIOs 0 to 31 on device: gpio
> > [ 0.185882] OMAP GPIO hardware version 0.1
> > [ 0.186767] gpiochip_add: registered GPIOs 32 to 63 on device: gpio
> > [ 0.187744] gpiochip_add: registered GPIOs 64 to 95 on device: gpio
> > [ 0.188751] gpiochip_add: registered GPIOs 96 to 127 on device: gpio
> > [ 0.189819] gpiochip_add: registered GPIOs 128 to 159 on device: gpio
> > [ 0.190917] gpiochip_add: registered GPIOs 160 to 191 on device: gpio
>
> yeah, but you can get all of that for free from driver core. Just add
> one platform_device for each bank and make the omap-gpio.c only
> understand one bank. No tricks.
>
> What I'm trying to say is to remove the Bank array or list_head and make
> probe() get called 6 times by creating 6 omap_gpio platform_devices.
>
> From probe you cann gpiochip_add() once and only once.
^^^^
call
I actually just took the time to go over the driver and that's what it
does. So the list_head is only there fo the nasty cpuidle stuff below:
> > That list is only used to iterate over all the instances during CPU idle:
> >
> > void omap2_gpio_prepare_for_idle(int pwr_mode)
> > {
> > struct gpio_bank *bank;
> >
> > list_for_each_entry(bank, &omap_gpio_list, node) {
> > if (!bank->mod_usage || !bank->loses_context)
> > continue;
> >
> > bank->power_mode = pwr_mode;
> >
> > pm_runtime_put_sync_suspend(bank->dev);
> > }
> > }
> >
> > void omap2_gpio_resume_after_idle(void)
> > {
> > struct gpio_bank *bank;
> >
> > list_for_each_entry(bank, &omap_gpio_list, node) {
> > if (!bank->mod_usage || !bank->loses_context)
> > continue;
> >
> > pm_runtime_get_sync(bank->dev);
> > }
> > }
>
> that's the thing which is unnecessary, actually :-)
>
> Why do we even have this omap2_gpio_resume_after_idle() ? Can't the gpio
> driver handle its own PM or listen to cpuidle notificaitons for that ?
>
> I would like to understand why do we need this hack for pm runtime.
> Can't you just use ->prepare() and ->complete() from dev_pm_ops ?
This question remains. Why do we need those funtions ?
--
balbi
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