drivers/gpio/gpio-loongson1.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * GPIO Driver for Loongson 1 SoC
   4  *
   5  * Copyright (C) 2015-2023 Keguang Zhang <keguang.zhang@gmail.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/gpio/driver.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/bitops.h>
  12
  13 /* Loongson 1 GPIO Register Definitions */
  14 #define GPIO_CFG                0x0
  15 #define GPIO_DIR                0x10
  16 #define GPIO_DATA               0x20
  17 #define GPIO_OUTPUT             0x30
  18
  19 struct ls1x_gpio_chip {
  20         struct gpio_chip gc;
  21         void __iomem *reg_base;
  22 };
  23
  24 static int ls1x_gpio_request(struct gpio_chip *gc, unsigned int offset)
  25 {
  26         struct ls1x_gpio_chip *ls1x_gc = gpiochip_get_data(gc);
  27         unsigned long flags;
  28
  29         raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
  30         __raw_writel(__raw_readl(ls1x_gc->reg_base + GPIO_CFG) | BIT(offset),
  31                      ls1x_gc->reg_base + GPIO_CFG);
  32         raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  33
  34         return 0;
  35 }
  36
  37 static void ls1x_gpio_free(struct gpio_chip *gc, unsigned int offset)
  38 {
  39         struct ls1x_gpio_chip *ls1x_gc = gpiochip_get_data(gc);
  40         unsigned long flags;
  41
  42         raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
  43         __raw_writel(__raw_readl(ls1x_gc->reg_base + GPIO_CFG) & ~BIT(offset),
  44                      ls1x_gc->reg_base + GPIO_CFG);
  45         raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  46 }
  47
  48 static int ls1x_gpio_probe(struct platform_device *pdev)
  49 {
  50         struct device *dev = &pdev->dev;
  51         struct ls1x_gpio_chip *ls1x_gc;
  52         int ret;
  53
  54         ls1x_gc = devm_kzalloc(dev, sizeof(*ls1x_gc), GFP_KERNEL);
  55         if (!ls1x_gc)
  56                 return -ENOMEM;
  57
  58         ls1x_gc->reg_base = devm_platform_ioremap_resource(pdev, 0);
  59         if (IS_ERR(ls1x_gc->reg_base))
  60                 return PTR_ERR(ls1x_gc->reg_base);
  61
  62         ret = bgpio_init(&ls1x_gc->gc, dev, 4, ls1x_gc->reg_base + GPIO_DATA,
  63                          ls1x_gc->reg_base + GPIO_OUTPUT, NULL,
  64                          NULL, ls1x_gc->reg_base + GPIO_DIR, 0);
  65         if (ret)
  66                 goto err;
  67
  68         ls1x_gc->gc.owner = THIS_MODULE;
  69         ls1x_gc->gc.request = ls1x_gpio_request;
  70         ls1x_gc->gc.free = ls1x_gpio_free;
  71         /*
  72          * Clear ngpio to let gpiolib get the correct number
  73          * by reading ngpios property
  74          */
  75         ls1x_gc->gc.ngpio = 0;
  76
  77         ret = devm_gpiochip_add_data(dev, &ls1x_gc->gc, ls1x_gc);
  78         if (ret)
  79                 goto err;
  80
  81         platform_set_drvdata(pdev, ls1x_gc);
  82
  83         dev_info(dev, "GPIO controller registered with %d pins\n",
  84                  ls1x_gc->gc.ngpio);
  85
  86         return 0;
  87 err:
  88         dev_err(dev, "failed to register GPIO controller\n");
  89         return ret;
  90 }
  91
  92 static const struct of_device_id ls1x_gpio_dt_ids[] = {
  93         { .compatible = "loongson,ls1x-gpio" },
  94         { /* sentinel */ }
  95 };
  96 MODULE_DEVICE_TABLE(of, ls1x_gpio_dt_ids);
  97
  98 static struct platform_driver ls1x_gpio_driver = {
  99         .probe  = ls1x_gpio_probe,
 100         .driver = {
 101                 .name   = "ls1x-gpio",
 102                 .of_match_table = ls1x_gpio_dt_ids,
 103         },
 104 };
 105
 106 module_platform_driver(ls1x_gpio_driver);
 107
 108 MODULE_AUTHOR("Keguang Zhang <keguang.zhang@gmail.com>");
 109 MODULE_DESCRIPTION("Loongson1 GPIO driver");
 110 MODULE_LICENSE("GPL");