Re: [PATCH V12 2/2] pinctrl: max77620: add pincontrol driver for MAX77620/MAX20024

On Tue, May 24, 2016 at 1:18 PM, Laxman Dewangan [off-list ref] wrote:

In this driver, it is configuration via pinctrl. Here pincontrol and gpio
driver share same registers.
Now, as we have the method to configure the open drain bit from the GPIO
interface, we really dont need to do this from pinctrl framework.

OK good that works too...

For doing from GPIO framework, the client need to aware that gpio is open
drain type.

Can we make something that open drain of pins can be provided via some
common interface like DT of controller based on platforms configuration  and
client need not to worry about this? For client, it will be simple gpio
calls.

We have GPIO_OPEN_DRAIN in
include/dt-bindings/gpio/gpio.h
that can be added on the consumer side of the GPIO line
in the DT, it should work (just like GPIO_ACTIVE_LOW for example).

For descriptor tables
include/linux/gpio/machine.h
provides the same mechanism with the flag GPIO_OPEN_DRAIN

Notice that in both cases it is the consumer that specifies that it
needs the line to be set up as open drain, not the controller,
as it is a resource, the consumer needs to request what it needs.

So this can be done already today. Unless there is some bug.

Yours,
Linus Walleij