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 */
31 static 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
gpio_line_config(int line,int direction)38 static 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
gpio_line_get(int line)54 static int gpio_line_get(int line)
55 {
56 return !!(readl(IOP3XX_GPID) & BIT(line));
57 }
58
gpio_line_set(int line,int value)59 static 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
iop3xx_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)75 static int iop3xx_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
76 {
77 gpio_line_config(gpio, GPIO_IN);
78 return 0;
79 }
80
iop3xx_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)81 static 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
iop3xx_gpio_get_value(struct gpio_chip * chip,unsigned gpio)88 static int iop3xx_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
89 {
90 return gpio_line_get(gpio);
91 }
92
iop3xx_gpio_set_value(struct gpio_chip * chip,unsigned gpio,int value)93 static void iop3xx_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value)
94 {
95 gpio_line_set(gpio, value);
96 }
97
98 static 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
iop3xx_gpio_probe(struct platform_device * pdev)108 static 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
120 static struct platform_driver iop3xx_gpio_driver = {
121 .driver = {
122 .name = "gpio-iop",
123 .owner = THIS_MODULE,
124 },
125 .probe = iop3xx_gpio_probe,
126 };
127
iop3xx_gpio_init(void)128 static int __init iop3xx_gpio_init(void)
129 {
130 return platform_driver_register(&iop3xx_gpio_driver);
131 }
132 arch_initcall(iop3xx_gpio_init);
133
134 MODULE_DESCRIPTION("GPIO handling for Intel IOP3xx processors");
135 MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>");
136 MODULE_LICENSE("GPL");
137