drivers/gpio/gpio-amdpt.c

   1 /*
   2  * AMD Promontory GPIO driver
   3  *
   4  * Copyright (C) 2015 ASMedia Technology Inc.
   5  * Author: YD Tseng <yd_tseng@asmedia.com.tw>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/gpio/driver.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/acpi.h>
  17 #include <linux/platform_device.h>
  18
  19 #define PT_TOTAL_GPIO 8
  20
  21 /* PCI-E MMIO register offsets */
  22 #define PT_DIRECTION_REG   0x00
  23 #define PT_INPUTDATA_REG   0x04
  24 #define PT_OUTPUTDATA_REG  0x08
  25 #define PT_CLOCKRATE_REG   0x0C
  26 #define PT_SYNC_REG        0x28
  27
  28 struct pt_gpio_chip {
  29         struct gpio_chip         gc;
  30         void __iomem             *reg_base;
  31 };
  32
  33 static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
  34 {
  35         struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  36         unsigned long flags;
  37         u32 using_pins;
  38
  39         dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
  40
  41         spin_lock_irqsave(&gc->bgpio_lock, flags);
  42
  43         using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  44         if (using_pins & BIT(offset)) {
  45                 dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
  46                          offset);
  47                 spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  48                 return -EINVAL;
  49         }
  50
  51         writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
  52
  53         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  54
  55         return 0;
  56 }
  57
  58 static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
  59 {
  60         struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  61         unsigned long flags;
  62         u32 using_pins;
  63
  64         spin_lock_irqsave(&gc->bgpio_lock, flags);
  65
  66         using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  67         using_pins &= ~BIT(offset);
  68         writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
  69
  70         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  71
  72         dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
  73 }
  74
  75 static int pt_gpio_probe(struct platform_device *pdev)
  76 {
  77         struct device *dev = &pdev->dev;
  78         struct acpi_device *acpi_dev;
  79         acpi_handle handle = ACPI_HANDLE(dev);
  80         struct pt_gpio_chip *pt_gpio;
  81         struct resource *res_mem;
  82         int ret = 0;
  83
  84         if (acpi_bus_get_device(handle, &acpi_dev)) {
  85                 dev_err(dev, "PT GPIO device node not found\n");
  86                 return -ENODEV;
  87         }
  88
  89         pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
  90         if (!pt_gpio)
  91                 return -ENOMEM;
  92
  93         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  94         if (!res_mem) {
  95                 dev_err(&pdev->dev, "Failed to get MMIO resource for PT GPIO.\n");
  96                 return -EINVAL;
  97         }
  98         pt_gpio->reg_base = devm_ioremap_resource(dev, res_mem);
  99         if (IS_ERR(pt_gpio->reg_base)) {
 100                 dev_err(&pdev->dev, "Failed to map MMIO resource for PT GPIO.\n");
 101                 return PTR_ERR(pt_gpio->reg_base);
 102         }
 103
 104         ret = bgpio_init(&pt_gpio->gc, dev, 4,
 105                          pt_gpio->reg_base + PT_INPUTDATA_REG,
 106                          pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
 107                          pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
 108                          BGPIOF_READ_OUTPUT_REG_SET);
 109         if (ret) {
 110                 dev_err(&pdev->dev, "bgpio_init failed\n");
 111                 return ret;
 112         }
 113
 114         pt_gpio->gc.owner            = THIS_MODULE;
 115         pt_gpio->gc.request          = pt_gpio_request;
 116         pt_gpio->gc.free             = pt_gpio_free;
 117         pt_gpio->gc.ngpio            = PT_TOTAL_GPIO;
 118 #if defined(CONFIG_OF_GPIO)
 119         pt_gpio->gc.of_node          = pdev->dev.of_node;
 120 #endif
 121         ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
 122         if (ret) {
 123                 dev_err(&pdev->dev, "Failed to register GPIO lib\n");
 124                 return ret;
 125         }
 126
 127         platform_set_drvdata(pdev, pt_gpio);
 128
 129         /* initialize register setting */
 130         writel(0, pt_gpio->reg_base + PT_SYNC_REG);
 131         writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
 132
 133         dev_dbg(&pdev->dev, "PT GPIO driver loaded\n");
 134         return ret;
 135 }
 136
 137 static int pt_gpio_remove(struct platform_device *pdev)
 138 {
 139         struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
 140
 141         gpiochip_remove(&pt_gpio->gc);
 142
 143         return 0;
 144 }
 145
 146 static const struct acpi_device_id pt_gpio_acpi_match[] = {
 147         { "AMDF030", 0 },
 148         { "AMDIF030", 0 },
 149         { },
 150 };
 151 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
 152
 153 static struct platform_driver pt_gpio_driver = {
 154         .driver = {
 155                 .name = "pt-gpio",
 156                 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
 157         },
 158         .probe = pt_gpio_probe,
 159         .remove = pt_gpio_remove,
 160 };
 161
 162 module_platform_driver(pt_gpio_driver);
 163
 164 MODULE_LICENSE("GPL");
 165 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
 166 MODULE_DESCRIPTION("AMD Promontory GPIO Driver");