1/*
2 * arch/arm/plat-iop/gpio.c
3 * GPIO handling for Intel IOP3xx processors.
4 *
5 * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or (at
10 * your option) any later version.
11 */
12
13#include <linux/device.h>
14#include <linux/init.h>
15#include <linux/types.h>
16#include <linux/errno.h>
17#include <linux/gpio.h>
18#include <linux/export.h>
19#include <linux/platform_device.h>
20#include <linux/bitops.h>
21#include <linux/io.h>
22
23#define IOP3XX_N_GPIOS	8
24
25#define GPIO_IN			0
26#define GPIO_OUT		1
27#define GPIO_LOW		0
28#define GPIO_HIGH		1
29
30/* Memory base offset */
31static void __iomem *base;
32
33#define IOP3XX_GPIO_REG(reg)	(base + (reg))
34#define IOP3XX_GPOE		IOP3XX_GPIO_REG(0x0000)
35#define IOP3XX_GPID		IOP3XX_GPIO_REG(0x0004)
36#define IOP3XX_GPOD		IOP3XX_GPIO_REG(0x0008)
37
38static void gpio_line_config(int line, int direction)
39{
40	unsigned long flags;
41	u32 val;
42
43	local_irq_save(flags);
44	val = readl(IOP3XX_GPOE);
45	if (direction == GPIO_IN) {
46		val |= BIT(line);
47	} else if (direction == GPIO_OUT) {
48		val &= ~BIT(line);
49	}
50	writel(val, IOP3XX_GPOE);
51	local_irq_restore(flags);
52}
53
54static int gpio_line_get(int line)
55{
56	return !!(readl(IOP3XX_GPID) & BIT(line));
57}
58
59static void gpio_line_set(int line, int value)
60{
61	unsigned long flags;
62	u32 val;
63
64	local_irq_save(flags);
65	val = readl(IOP3XX_GPOD);
66	if (value == GPIO_LOW) {
67		val &= ~BIT(line);
68	} else if (value == GPIO_HIGH) {
69		val |= BIT(line);
70	}
71	writel(val, IOP3XX_GPOD);
72	local_irq_restore(flags);
73}
74
75static int iop3xx_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
76{
77	gpio_line_config(gpio, GPIO_IN);
78	return 0;
79}
80
81static int iop3xx_gpio_direction_output(struct gpio_chip *chip, unsigned gpio, int level)
82{
83	gpio_line_set(gpio, level);
84	gpio_line_config(gpio, GPIO_OUT);
85	return 0;
86}
87
88static int iop3xx_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
89{
90	return gpio_line_get(gpio);
91}
92
93static void iop3xx_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value)
94{
95	gpio_line_set(gpio, value);
96}
97
98static struct gpio_chip iop3xx_chip = {
99	.label			= "iop3xx",
100	.direction_input	= iop3xx_gpio_direction_input,
101	.get			= iop3xx_gpio_get_value,
102	.direction_output	= iop3xx_gpio_direction_output,
103	.set			= iop3xx_gpio_set_value,
104	.base			= 0,
105	.ngpio			= IOP3XX_N_GPIOS,
106};
107
108static int iop3xx_gpio_probe(struct platform_device *pdev)
109{
110	struct resource *res;
111
112	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
113	base = devm_ioremap_resource(&pdev->dev, res);
114	if (IS_ERR(base))
115		return PTR_ERR(base);
116
117	return gpiochip_add(&iop3xx_chip);
118}
119
120static struct platform_driver iop3xx_gpio_driver = {
121	.driver = {
122		.name = "gpio-iop",
123	},
124	.probe = iop3xx_gpio_probe,
125};
126
127static int __init iop3xx_gpio_init(void)
128{
129	return platform_driver_register(&iop3xx_gpio_driver);
130}
131arch_initcall(iop3xx_gpio_init);
132