tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * GPIO Driver for Loongson 1 SoC
3 *
4 * Copyright (C) 2015-2016 Zhang, Keguang <keguang.zhang@gmail.com>
5 *
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
9 */
10
11#include <linux/module.h>
12#include <linux/gpio/driver.h>
13#include <linux/platform_device.h>
14#include <linux/bitops.h>
15
16/* Loongson 1 GPIO Register Definitions */
17#define GPIO_CFG 0x0
18#define GPIO_DIR 0x10
19#define GPIO_DATA 0x20
20#define GPIO_OUTPUT 0x30
21
22static void __iomem *gpio_reg_base;
23
24static int ls1x_gpio_request(struct gpio_chip *gc, unsigned int offset)
25{
26 unsigned long flags;
27
28 spin_lock_irqsave(&gc->bgpio_lock, flags);
29 __raw_writel(__raw_readl(gpio_reg_base + GPIO_CFG) | BIT(offset),
30 gpio_reg_base + GPIO_CFG);
31 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
32
33 return 0;
34}
35
36static void ls1x_gpio_free(struct gpio_chip *gc, unsigned int offset)
37{
38 unsigned long flags;
39
40 spin_lock_irqsave(&gc->bgpio_lock, flags);
41 __raw_writel(__raw_readl(gpio_reg_base + GPIO_CFG) & ~BIT(offset),
42 gpio_reg_base + GPIO_CFG);
43 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
44}
45
46static int ls1x_gpio_probe(struct platform_device *pdev)
47{
48 struct device *dev = &pdev->dev;
49 struct gpio_chip *gc;
50 struct resource *res;
51 int ret;
52
53 gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
54 if (!gc)
55 return -ENOMEM;
56
57 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
58 gpio_reg_base = devm_ioremap_resource(dev, res);
59 if (IS_ERR(gpio_reg_base))
60 return PTR_ERR(gpio_reg_base);
61
62 ret = bgpio_init(gc, dev, 4, gpio_reg_base + GPIO_DATA,
63 gpio_reg_base + GPIO_OUTPUT, NULL,
64 NULL, gpio_reg_base + GPIO_DIR, 0);
65 if (ret)
66 goto err;
67
68 gc->owner = THIS_MODULE;
69 gc->request = ls1x_gpio_request;
70 gc->free = ls1x_gpio_free;
71 gc->base = pdev->id * 32;
72
73 ret = devm_gpiochip_add_data(dev, gc, NULL);
74 if (ret)
75 goto err;
76
77 platform_set_drvdata(pdev, gc);
78 dev_info(dev, "Loongson1 GPIO driver registered\n");
79
80 return 0;
81err:
82 dev_err(dev, "failed to register GPIO device\n");
83 return ret;
84}
85
86static struct platform_driver ls1x_gpio_driver = {
87 .probe = ls1x_gpio_probe,
88 .driver = {
89 .name = "ls1x-gpio",
90 },
91};
92
93module_platform_driver(ls1x_gpio_driver);
94
95MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
96MODULE_DESCRIPTION("Loongson1 GPIO driver");
97MODULE_LICENSE("GPL");