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
  15 /* Loongson 1 GPIO Register Definitions */
  16 #define GPIO_CFG                0x0
  17 #define GPIO_DIR                0x10
  18 #define GPIO_DATA               0x20
  19 #define GPIO_OUTPUT             0x30
  20
  21 static void __iomem *gpio_reg_base;
  22
  23 static int ls1x_gpio_request(struct gpio_chip *gc, unsigned int offset)
  24 {
  25         unsigned long pinmask = gc->pin2mask(gc, offset);
  26         unsigned long flags;
  27
  28         spin_lock_irqsave(&gc->bgpio_lock, flags);
  29         __raw_writel(__raw_readl(gpio_reg_base + GPIO_CFG) | pinmask,
  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 pinmask = gc->pin2mask(gc, offset);
  39         unsigned long flags;
  40
  41         spin_lock_irqsave(&gc->bgpio_lock, flags);
  42         __raw_writel(__raw_readl(gpio_reg_base + GPIO_CFG) & ~pinmask,
  43                      gpio_reg_base + GPIO_CFG);
  44         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  45 }
  46
  47 static int ls1x_gpio_probe(struct platform_device *pdev)
  48 {
  49         struct device *dev = &pdev->dev;
  50         struct gpio_chip *gc;
  51         struct resource *res;
  52         int ret;
  53
  54         gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
  55         if (!gc)
  56                 return -ENOMEM;
  57
  58         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  59         gpio_reg_base = devm_ioremap_resource(dev, res);
  60         if (IS_ERR(gpio_reg_base))
  61                 return PTR_ERR(gpio_reg_base);
  62
  63         ret = bgpio_init(gc, dev, 4, gpio_reg_base + GPIO_DATA,
  64                          gpio_reg_base + GPIO_OUTPUT, NULL,
  65                          NULL, gpio_reg_base + GPIO_DIR, 0);
  66         if (ret)
  67                 goto err;
  68
  69         gc->owner = THIS_MODULE;
  70         gc->request = ls1x_gpio_request;
  71         gc->free = ls1x_gpio_free;
  72         gc->base = pdev->id * 32;
  73
  74         ret = devm_gpiochip_add_data(dev, gc, NULL);
  75         if (ret)
  76                 goto err;
  77
  78         platform_set_drvdata(pdev, gc);
  79         dev_info(dev, "Loongson1 GPIO driver registered\n");
  80
  81         return 0;
  82 err:
  83         dev_err(dev, "failed to register GPIO device\n");
  84         return ret;
  85 }
  86
  87 static struct platform_driver ls1x_gpio_driver = {
  88         .probe  = ls1x_gpio_probe,
  89         .driver = {
  90                 .name   = "ls1x-gpio",
  91         },
  92 };
  93
  94 module_platform_driver(ls1x_gpio_driver);
  95
  96 MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
  97 MODULE_DESCRIPTION("Loongson1 GPIO driver");
  98 MODULE_LICENSE("GPL");