a4ce4b8dae
As we want gpio_chip .get() calls to be able to return negative error codes and propagate to drivers, we need to go over all drivers and make sure their return values are clamped to [0,1]. We do this by using the ret = !!(val) design pattern. Cc: Anton Vorontsov <anton@enomsg.org> Cc: Anatolij Gustschin <agust@denx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
153 lines
3.2 KiB
C
153 lines
3.2 KiB
C
/*
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* Simple Memory-Mapped GPIOs
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*
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* Copyright (c) MontaVista Software, Inc. 2008.
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*
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* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/ioport.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <linux/gpio.h>
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#include <linux/slab.h>
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#include <asm/prom.h>
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#include "simple_gpio.h"
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struct u8_gpio_chip {
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struct of_mm_gpio_chip mm_gc;
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spinlock_t lock;
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/* shadowed data register to clear/set bits safely */
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u8 data;
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};
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static struct u8_gpio_chip *to_u8_gpio_chip(struct of_mm_gpio_chip *mm_gc)
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{
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return container_of(mm_gc, struct u8_gpio_chip, mm_gc);
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}
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static u8 u8_pin2mask(unsigned int pin)
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{
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return 1 << (8 - 1 - pin);
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}
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static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio)
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{
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struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
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return !!(in_8(mm_gc->regs) & u8_pin2mask(gpio));
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}
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static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
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struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc);
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unsigned long flags;
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spin_lock_irqsave(&u8_gc->lock, flags);
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if (val)
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u8_gc->data |= u8_pin2mask(gpio);
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else
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u8_gc->data &= ~u8_pin2mask(gpio);
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out_8(mm_gc->regs, u8_gc->data);
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spin_unlock_irqrestore(&u8_gc->lock, flags);
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}
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static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
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{
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return 0;
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}
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static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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u8_gpio_set(gc, gpio, val);
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return 0;
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}
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static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc)
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{
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struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc);
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u8_gc->data = in_8(mm_gc->regs);
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}
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static int __init u8_simple_gpiochip_add(struct device_node *np)
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{
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int ret;
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struct u8_gpio_chip *u8_gc;
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struct of_mm_gpio_chip *mm_gc;
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struct gpio_chip *gc;
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u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL);
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if (!u8_gc)
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return -ENOMEM;
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spin_lock_init(&u8_gc->lock);
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mm_gc = &u8_gc->mm_gc;
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gc = &mm_gc->gc;
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mm_gc->save_regs = u8_gpio_save_regs;
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gc->ngpio = 8;
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gc->direction_input = u8_gpio_dir_in;
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gc->direction_output = u8_gpio_dir_out;
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gc->get = u8_gpio_get;
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gc->set = u8_gpio_set;
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ret = of_mm_gpiochip_add(np, mm_gc);
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if (ret)
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goto err;
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return 0;
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err:
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kfree(u8_gc);
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return ret;
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}
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void __init simple_gpiochip_init(const char *compatible)
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{
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struct device_node *np;
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for_each_compatible_node(np, NULL, compatible) {
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int ret;
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struct resource r;
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ret = of_address_to_resource(np, 0, &r);
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if (ret)
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goto err;
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switch (resource_size(&r)) {
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case 1:
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ret = u8_simple_gpiochip_add(np);
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if (ret)
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goto err;
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break;
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default:
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/*
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* Whenever you need support for GPIO bank width > 1,
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* please just turn u8_ code into huge macros, and
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* construct needed uX_ code with it.
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*/
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ret = -ENOSYS;
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goto err;
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}
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continue;
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err:
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pr_err("%s: registration failed, status %d\n",
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np->full_name, ret);
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}
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}
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