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
  22 static void __iomem *gpio_reg_base;
  23
  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
  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
  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");