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/gpio/generic.h> 13 #include <linux/spinlock.h> 14 #include <linux/acpi.h> 15 #include <linux/platform_device.h> 16 17 #define PT_TOTAL_GPIO 8 18 #define PT_TOTAL_GPIO_EX 24 19 20 /* PCI-E MMIO register offsets */ 21 #define PT_DIRECTION_REG 0x00 22 #define PT_INPUTDATA_REG 0x04 23 #define PT_OUTPUTDATA_REG 0x08 24 #define PT_CLOCKRATE_REG 0x0C 25 #define PT_SYNC_REG 0x28 26 27 struct pt_gpio_chip { 28 struct gpio_generic_chip chip; 29 void __iomem *reg_base; 30 }; 31 32 static int pt_gpio_request(struct gpio_chip *gc, unsigned offset) 33 { 34 struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc); 35 struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc); 36 u32 using_pins; 37 38 dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset); 39 40 guard(gpio_generic_lock_irqsave)(gen_gc); 41 42 using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG); 43 if (using_pins & BIT(offset)) { 44 dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n", 45 offset); 46 return -EINVAL; 47 } 48 49 writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG); 50 51 return 0; 52 } 53 54 static void pt_gpio_free(struct gpio_chip *gc, unsigned offset) 55 { 56 struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc); 57 struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc); 58 u32 using_pins; 59 60 guard(gpio_generic_lock_irqsave)(gen_gc); 61 62 using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG); 63 using_pins &= ~BIT(offset); 64 writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG); 65 66 dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset); 67 } 68 69 static int pt_gpio_probe(struct platform_device *pdev) 70 { 71 struct gpio_generic_chip_config config; 72 struct device *dev = &pdev->dev; 73 struct pt_gpio_chip *pt_gpio; 74 int ret = 0; 75 76 if (!ACPI_COMPANION(dev)) { 77 dev_err(dev, "PT GPIO device node not found\n"); 78 return -ENODEV; 79 } 80 81 pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL); 82 if (!pt_gpio) 83 return -ENOMEM; 84 85 pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0); 86 if (IS_ERR(pt_gpio->reg_base)) { 87 dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n"); 88 return PTR_ERR(pt_gpio->reg_base); 89 } 90 91 config = (struct gpio_generic_chip_config) { 92 .dev = dev, 93 .sz = 4, 94 .dat = pt_gpio->reg_base + PT_INPUTDATA_REG, 95 .set = pt_gpio->reg_base + PT_OUTPUTDATA_REG, 96 .dirout = pt_gpio->reg_base + PT_DIRECTION_REG, 97 .flags = GPIO_GENERIC_READ_OUTPUT_REG_SET, 98 }; 99 100 ret = gpio_generic_chip_init(&pt_gpio->chip, &config); 101 if (ret) { 102 dev_err(dev, "failed to initialize the generic GPIO chip\n"); 103 return ret; 104 } 105 106 pt_gpio->chip.gc.owner = THIS_MODULE; 107 pt_gpio->chip.gc.request = pt_gpio_request; 108 pt_gpio->chip.gc.free = pt_gpio_free; 109 pt_gpio->chip.gc.ngpio = (uintptr_t)device_get_match_data(dev); 110 111 ret = devm_gpiochip_add_data(dev, &pt_gpio->chip.gc, pt_gpio); 112 if (ret) { 113 dev_err(dev, "Failed to register GPIO lib\n"); 114 return ret; 115 } 116 117 platform_set_drvdata(pdev, pt_gpio); 118 119 /* initialize register setting */ 120 writel(0, pt_gpio->reg_base + PT_SYNC_REG); 121 writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG); 122 123 dev_dbg(dev, "PT GPIO driver loaded\n"); 124 return ret; 125 } 126 127 static const struct acpi_device_id pt_gpio_acpi_match[] = { 128 { "AMDF030", PT_TOTAL_GPIO }, 129 { "AMDIF030", PT_TOTAL_GPIO }, 130 { "AMDIF031", PT_TOTAL_GPIO_EX }, 131 { }, 132 }; 133 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match); 134 135 static struct platform_driver pt_gpio_driver = { 136 .driver = { 137 .name = "pt-gpio", 138 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match), 139 }, 140 .probe = pt_gpio_probe, 141 }; 142 143 module_platform_driver(pt_gpio_driver); 144 145 MODULE_LICENSE("GPL"); 146 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>"); 147 MODULE_DESCRIPTION("AMD Promontory GPIO Driver"); 148