LXR linux/drivers/gpio/gpio-loongson1.c

   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");
  98