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
22 static void __iomem *gpio_reg_base;
23
ls1x_gpio_request(struct gpio_chip * gc,unsigned int offset)24 static 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
ls1x_gpio_free(struct gpio_chip * gc,unsigned int offset)36 static 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
ls1x_gpio_probe(struct platform_device * pdev)46 static int ls1x_gpio_probe(struct platform_device *pdev)
47 {
48 struct device *dev = &pdev->dev;
49 struct gpio_chip *gc;
50 int ret;
51
52 gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
53 if (!gc)
54 return -ENOMEM;
55
56 gpio_reg_base = devm_platform_ioremap_resource(pdev, 0);
57 if (IS_ERR(gpio_reg_base))
58 return PTR_ERR(gpio_reg_base);
59
60 ret = bgpio_init(gc, dev, 4, gpio_reg_base + GPIO_DATA,
61 gpio_reg_base + GPIO_OUTPUT, NULL,
62 NULL, gpio_reg_base + GPIO_DIR, 0);
63 if (ret)
64 goto err;
65
66 gc->owner = THIS_MODULE;
67 gc->request = ls1x_gpio_request;
68 gc->free = ls1x_gpio_free;
69 gc->base = pdev->id * 32;
70
71 ret = devm_gpiochip_add_data(dev, gc, NULL);
72 if (ret)
73 goto err;
74
75 platform_set_drvdata(pdev, gc);
76 dev_info(dev, "Loongson1 GPIO driver registered\n");
77
78 return 0;
79 err:
80 dev_err(dev, "failed to register GPIO device\n");
81 return ret;
82 }
83
84 static struct platform_driver ls1x_gpio_driver = {
85 .probe = ls1x_gpio_probe,
86 .driver = {
87 .name = "ls1x-gpio",
88 },
89 };
90
91 module_platform_driver(ls1x_gpio_driver);
92
93 MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
94 MODULE_DESCRIPTION("Loongson1 GPIO driver");
95 MODULE_LICENSE("GPL");
96