[RFC] Add Generic GPIO driver

[Sascha Hauer]

On Mon, Feb 18, 2013 at 02:13:22PM +0400, Alexander Shiyan wrote:
> > On Fri, Feb 15, 2013 at 10:49:27PM +0400, Alexander Shiyan wrote:
> > > This patch adds generic memory-mapped GPIO controller support.
> > > Code taken from Linux Kernel and adopted for barebox.
> > 
> > I'm fine with this if you add a user for it. I wonder though if it's
> > worth it to have this driver for barebox. If I have a driver in the
> > kernel that already uses it, then this makes it simple to copy it, but
> > should I have to write a new gpio driver, I'm unsure if it's simpler
> > to write a new gpio driver or to register with the generic gpio
> > driver.
> 
> Here's an example that I'm checking:

Ok, this indeed looks nice and short. You convinced me ;)

As said, I'm fine with the generic gpio driver if you add the below as
first user.

Sascha

> 
> /*
>  * Copyright (C) 2013 Alexander Shiyan <shc_work at mail.ru>
>  *
>  * This program is free software; you can redistribute it and/or
>  * modify it under the terms of the GNU General Public License as
>  * published by the Free Software Foundation; either version 2 of
>  * the License, or (at your option) any later version.
>  */
> 
> #include <init.h>
> #include <common.h>
> #include <malloc.h>
> 
> #include <linux/basic_mmio_gpio.h>
> 
> static int clps711x_gpio_probe(struct device_d *dev)
> {
> 	int err;
> 	void __iomem *dat, *dir, *dir_inv;
> 	struct bgpio_chip *bgc;
> 	struct bgpio_pdata *pdata = dev->platform_data;
> 
> 	if (!pdata)
> 		return -ENODATA;
> 
> 	dat = dev_request_mem_region_by_name(dev, "dat");
> 	dir = dev_request_mem_region_by_name(dev, "dir");
> 	dir_inv = dev_request_mem_region_by_name(dev, "dir_inv");
> 	if (!dat || (!dir && !dir_inv))
> 		return -EINVAL;
> 
> 	bgc = xzalloc(sizeof(struct bgpio_chip));
> 	if (!bgc)
> 		return -ENOMEM;
> 
> 	err = bgpio_init(bgc, dev, 1, dat, NULL, NULL, dir, dir_inv, 0);
> 	if (err) {
> 		free(bgc);
> 		return err;
> 	}
> 
> 	bgc->gc.base = pdata->base;
> 	bgc->gc.ngpio = pdata->ngpio;
> 
> 	return gpiochip_add(&bgc->gc);
> }
> 
> static struct driver_d clps711x_gpio_driver = {
> 	.name	= "clps711x-gpio",
> 	.probe	= clps711x_gpio_probe,
> };
> 
> static __init int clps711x_gpio_register(void)
> {
> 	return platform_driver_register(&clps711x_gpio_driver);
> }
> coredevice_initcall(clps711x_gpio_register);
> 
> ---

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