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 int ret = 0; 82 83 if (acpi_bus_get_device(handle, &acpi_dev)) { 84 dev_err(dev, "PT GPIO device node not found\n"); 85 return -ENODEV; 86 } 87 88 pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL); 89 if (!pt_gpio) 90 return -ENOMEM; 91 92 pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0); 93 if (IS_ERR(pt_gpio->reg_base)) { 94 dev_err(&pdev->dev, "Failed to map MMIO resource for PT GPIO.\n"); 95 return PTR_ERR(pt_gpio->reg_base); 96 } 97 98 ret = bgpio_init(&pt_gpio->gc, dev, 4, 99 pt_gpio->reg_base + PT_INPUTDATA_REG, 100 pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL, 101 pt_gpio->reg_base + PT_DIRECTION_REG, NULL, 102 BGPIOF_READ_OUTPUT_REG_SET); 103 if (ret) { 104 dev_err(&pdev->dev, "bgpio_init failed\n"); 105 return ret; 106 } 107 108 pt_gpio->gc.owner = THIS_MODULE; 109 pt_gpio->gc.request = pt_gpio_request; 110 pt_gpio->gc.free = pt_gpio_free; 111 pt_gpio->gc.ngpio = PT_TOTAL_GPIO; 112 #if defined(CONFIG_OF_GPIO) 113 pt_gpio->gc.of_node = pdev->dev.of_node; 114 #endif 115 ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio); 116 if (ret) { 117 dev_err(&pdev->dev, "Failed to register GPIO lib\n"); 118 return ret; 119 } 120 121 platform_set_drvdata(pdev, pt_gpio); 122 123 /* initialize register setting */ 124 writel(0, pt_gpio->reg_base + PT_SYNC_REG); 125 writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG); 126 127 dev_dbg(&pdev->dev, "PT GPIO driver loaded\n"); 128 return ret; 129 } 130 131 static int pt_gpio_remove(struct platform_device *pdev) 132 { 133 struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev); 134 135 gpiochip_remove(&pt_gpio->gc); 136 137 return 0; 138 } 139 140 static const struct acpi_device_id pt_gpio_acpi_match[] = { 141 { "AMDF030", 0 }, 142 { "AMDIF030", 0 }, 143 { }, 144 }; 145 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match); 146 147 static struct platform_driver pt_gpio_driver = { 148 .driver = { 149 .name = "pt-gpio", 150 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match), 151 }, 152 .probe = pt_gpio_probe, 153 .remove = pt_gpio_remove, 154 }; 155 156 module_platform_driver(pt_gpio_driver); 157 158 MODULE_LICENSE("GPL"); 159 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>"); 160 MODULE_DESCRIPTION("AMD Promontory GPIO Driver"); 161