[PATCH 1/1] ARM: kirkwood: Add support for RaidSonic

On Tue, 1 May 2012, Andrew Lunn wrote:

Hi Simon

The patch looks good.

+static void ib62x0_power_off(void)
+{
+       gpio_set_value(IB62X0_GPIO_POWER_OFF, 1);
+}

Seeing this set of a train of thought. I have a feature creep
request. Nice to have, i.e. not required to acceptance. This patterns
of using a GPIO line to turn the hardware off is seen quite a few
times. e.g.

mach-kirkwood/netspace_v2-setup.c
mach-orion5x/mv2120-setup.c
mach-kirkwood/d2net_v2-setup.c
mach-kirkwood/netspace_v2-setup.c

and a few more.

How about writing a gpio-poweroff platform driver? It would take a
platform_data structure which lists which GPIO line to use, and if it
should be active high/low. The probe function would take control of
the GPIO line, set it to inactive state, and output. It would also
register a function for pm_power_off(). When that function is called,
it toggles the GPIO to turn the power off.

Then wrap all this up in a DT binding.

I've been thinking about this too, would make a lot of sense. Most of the 
gpio-poweroff driver would be easy, although registering the power_off 
function wasn't immediately obvious.

In the process of this though, I stumbled on the gpio-regulator driver and 
emails suggesting to use this. It seems like it would make sense for the 
GPIO pins on the DNS-320 that turn on/off SATA drives, and intend to have 
a go at using this instead. This could possibly be used for power off too, 
but might be streatching it a bit too far.

    Andrew

-- 
Jamie Lentin