Re: [PATCHv3 0/7] gpio: extend basic_mmio_gpio for different controllers

[Anton Vorontsov <cbouatmailru@gmail.com>]

On Tue, May 03, 2011 at 03:13:20PM -0600, Grant Likely wrote:
> > struct gpio_mmio_generic {
> >        spinlock_t      lock;
> >
> >        /* initialized by user */
> >        unsigned long   reg_data;
> >        unsigned long   reg_set;
> >        unsigned long   reg_clr;
> >        unsigned long   reg_dir;
> >
> >        void __iomem    *reg_base;

This assumes that all reg_* will be mapped with a single ioremap().
My solution (see below) doesn't have this issue.

> > void gpio_mmio_generic_setup(struct gpio_mmio_generic *gmg, int register_width);
> > int gpio_mmio_generic_add(struct gpio_mmio_generic *gmg);
> > void gpio_mmio_generic_remove(struct gpio_mmio_generic *gmg);

I'm not sure you need that complex API.

> > gpio_mmio_generic_setup() sets up the common callback ops in the
> > embedded gpio_chip, but the decisions it makes could be overridden by
> > the user before calling gpio_mmio_generic_add().
> >
> > I've not had time to prototype this yet, but I wanted to get it
> > written down and out onto the list for feedback since I probably won't
> > have any chance to get to it until after UDS.  Bonus points to anyone
> > who wants to take the initiative to hack it together before I get to
> > it.  Extra bonus points to anyone who also converts some of the other
> > gpio controllers to use it.  :-D
> 
> And triple bonus points to anyone who thinks this is stupid and comes
> up with a better approach.  :-)

This isn't stupid. And I started working on this, so what about
http://lkml.org/lkml/2011/4/19/401 ? This is pretty much the same
that you propose.

Thanks.

-- 
Anton Vorontsov
Email: cbouatmailru@gmail.com