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"); 167