drivers/gpio/gpio-amdpt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AMD Promontory GPIO driver
   4  *
   5  * Copyright (C) 2015 ASMedia Technology Inc.
   6  * Author: YD Tseng <yd_tseng@asmedia.com.tw>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/gpio/driver.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/acpi.h>
  14 #include <linux/platform_device.h>
  15
  16 #define PT_TOTAL_GPIO 8
  17
  18 /* PCI-E MMIO register offsets */
  19 #define PT_DIRECTION_REG   0x00
  20 #define PT_INPUTDATA_REG   0x04
  21 #define PT_OUTPUTDATA_REG  0x08
  22 #define PT_CLOCKRATE_REG   0x0C
  23 #define PT_SYNC_REG        0x28
  24
  25 struct pt_gpio_chip {
  26         struct gpio_chip         gc;
  27         void __iomem             *reg_base;
  28 };
  29
  30 static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
  31 {
  32         struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  33         unsigned long flags;
  34         u32 using_pins;
  35
  36         dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
  37
  38         spin_lock_irqsave(&gc->bgpio_lock, flags);
  39
  40         using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  41         if (using_pins & BIT(offset)) {
  42                 dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
  43                          offset);
  44                 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  45                 return -EINVAL;
  46         }
  47
  48         writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
  49
  50         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  51
  52         return 0;
  53 }
  54
  55 static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
  56 {
  57         struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  58         unsigned long flags;
  59         u32 using_pins;
  60
  61         spin_lock_irqsave(&gc->bgpio_lock, flags);
  62
  63         using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  64         using_pins &= ~BIT(offset);
  65         writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
  66
  67         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  68
  69         dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
  70 }
  71
  72 static int pt_gpio_probe(struct platform_device *pdev)
  73 {
  74         struct device *dev = &pdev->dev;
  75         struct acpi_device *acpi_dev;
  76         acpi_handle handle = ACPI_HANDLE(dev);
  77         struct pt_gpio_chip *pt_gpio;
  78         int ret = 0;
  79
  80         if (acpi_bus_get_device(handle, &acpi_dev)) {
  81                 dev_err(dev, "PT GPIO device node not found\n");
  82                 return -ENODEV;
  83         }
  84
  85         pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
  86         if (!pt_gpio)
  87                 return -ENOMEM;
  88
  89         pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
  90         if (IS_ERR(pt_gpio->reg_base)) {
  91                 dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
  92                 return PTR_ERR(pt_gpio->reg_base);
  93         }
  94
  95         ret = bgpio_init(&pt_gpio->gc, dev, 4,
  96                          pt_gpio->reg_base + PT_INPUTDATA_REG,
  97                          pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
  98                          pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
  99                          BGPIOF_READ_OUTPUT_REG_SET);
 100         if (ret) {
 101                 dev_err(dev, "bgpio_init failed\n");
 102                 return ret;
 103         }
 104
 105         pt_gpio->gc.owner            = THIS_MODULE;
 106         pt_gpio->gc.request          = pt_gpio_request;
 107         pt_gpio->gc.free             = pt_gpio_free;
 108         pt_gpio->gc.ngpio            = PT_TOTAL_GPIO;
 109 #if defined(CONFIG_OF_GPIO)
 110         pt_gpio->gc.of_node          = dev->of_node;
 111 #endif
 112         ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
 113         if (ret) {
 114                 dev_err(dev, "Failed to register GPIO lib\n");
 115                 return ret;
 116         }
 117
 118         platform_set_drvdata(pdev, pt_gpio);
 119
 120         /* initialize register setting */
 121         writel(0, pt_gpio->reg_base + PT_SYNC_REG);
 122         writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
 123
 124         dev_dbg(dev, "PT GPIO driver loaded\n");
 125         return ret;
 126 }
 127
 128 static int pt_gpio_remove(struct platform_device *pdev)
 129 {
 130         struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
 131
 132         gpiochip_remove(&pt_gpio->gc);
 133
 134         return 0;
 135 }
 136
 137 static const struct acpi_device_id pt_gpio_acpi_match[] = {
 138         { "AMDF030", 0 },
 139         { "AMDIF030", 0 },
 140         { },
 141 };
 142 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
 143
 144 static struct platform_driver pt_gpio_driver = {
 145         .driver = {
 146                 .name = "pt-gpio",
 147                 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
 148         },
 149         .probe = pt_gpio_probe,
 150         .remove = pt_gpio_remove,
 151 };
 152
 153 module_platform_driver(pt_gpio_driver);
 154
 155 MODULE_LICENSE("GPL");
 156 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
 157 MODULE_DESCRIPTION("AMD Promontory GPIO Driver");