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 #define PT_TOTAL_GPIO_EX 24
  18
  19 /* PCI-E MMIO register offsets */
  20 #define PT_DIRECTION_REG   0x00
  21 #define PT_INPUTDATA_REG   0x04
  22 #define PT_OUTPUTDATA_REG  0x08
  23 #define PT_CLOCKRATE_REG   0x0C
  24 #define PT_SYNC_REG        0x28
  25
  26 struct pt_gpio_chip {
  27         struct gpio_chip         gc;
  28         void __iomem             *reg_base;
  29 };
  30
  31 static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
  32 {
  33         struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  34         unsigned long flags;
  35         u32 using_pins;
  36
  37         dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
  38
  39         raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
  40
  41         using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  42         if (using_pins & BIT(offset)) {
  43                 dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
  44                          offset);
  45                 raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  46                 return -EINVAL;
  47         }
  48
  49         writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
  50
  51         raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  52
  53         return 0;
  54 }
  55
  56 static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
  57 {
  58         struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  59         unsigned long flags;
  60         u32 using_pins;
  61
  62         raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
  63
  64         using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  65         using_pins &= ~BIT(offset);
  66         writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
  67
  68         raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  69
  70         dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
  71 }
  72
  73 static int pt_gpio_probe(struct platform_device *pdev)
  74 {
  75         struct device *dev = &pdev->dev;
  76         struct pt_gpio_chip *pt_gpio;
  77         int ret = 0;
  78
  79         if (!ACPI_COMPANION(dev)) {
  80                 dev_err(dev, "PT GPIO device node not found\n");
  81                 return -ENODEV;
  82         }
  83
  84         pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
  85         if (!pt_gpio)
  86                 return -ENOMEM;
  87
  88         pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
  89         if (IS_ERR(pt_gpio->reg_base)) {
  90                 dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
  91                 return PTR_ERR(pt_gpio->reg_base);
  92         }
  93
  94         ret = bgpio_init(&pt_gpio->gc, dev, 4,
  95                          pt_gpio->reg_base + PT_INPUTDATA_REG,
  96                          pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
  97                          pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
  98                          BGPIOF_READ_OUTPUT_REG_SET);
  99         if (ret) {
 100                 dev_err(dev, "bgpio_init failed\n");
 101                 return ret;
 102         }
 103
 104         pt_gpio->gc.owner            = THIS_MODULE;
 105         pt_gpio->gc.request          = pt_gpio_request;
 106         pt_gpio->gc.free             = pt_gpio_free;
 107         pt_gpio->gc.ngpio            = (uintptr_t)device_get_match_data(dev);
 108
 109         ret = devm_gpiochip_add_data(dev, &pt_gpio->gc, pt_gpio);
 110         if (ret) {
 111                 dev_err(dev, "Failed to register GPIO lib\n");
 112                 return ret;
 113         }
 114
 115         platform_set_drvdata(pdev, pt_gpio);
 116
 117         /* initialize register setting */
 118         writel(0, pt_gpio->reg_base + PT_SYNC_REG);
 119         writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
 120
 121         dev_dbg(dev, "PT GPIO driver loaded\n");
 122         return ret;
 123 }
 124
 125 static const struct acpi_device_id pt_gpio_acpi_match[] = {
 126         { "AMDF030", PT_TOTAL_GPIO },
 127         { "AMDIF030", PT_TOTAL_GPIO },
 128         { "AMDIF031", PT_TOTAL_GPIO_EX },
 129         { },
 130 };
 131 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
 132
 133 static struct platform_driver pt_gpio_driver = {
 134         .driver = {
 135                 .name = "pt-gpio",
 136                 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
 137         },
 138         .probe = pt_gpio_probe,
 139 };
 140
 141 module_platform_driver(pt_gpio_driver);
 142
 143 MODULE_LICENSE("GPL");
 144 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
 145 MODULE_DESCRIPTION("AMD Promontory GPIO Driver");