drivers/gpio/gpio-amdpt.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * AMD Promontory GPIO driver
0004  *
0005  * Copyright (C) 2015 ASMedia Technology Inc.
0006  * Author: YD Tseng <yd_tseng@asmedia.com.tw>
0007  */
0008
0009 #include <linux/kernel.h>
0010 #include <linux/module.h>
0011 #include <linux/gpio/driver.h>
0012 #include <linux/spinlock.h>
0013 #include <linux/acpi.h>
0014 #include <linux/platform_device.h>
0015
0016 #define PT_TOTAL_GPIO 8
0017 #define PT_TOTAL_GPIO_EX 24
0018
0019 /* PCI-E MMIO register offsets */
0020 #define PT_DIRECTION_REG   0x00
0021 #define PT_INPUTDATA_REG   0x04
0022 #define PT_OUTPUTDATA_REG  0x08
0023 #define PT_CLOCKRATE_REG   0x0C
0024 #define PT_SYNC_REG        0x28
0025
0026 struct pt_gpio_chip {
0027     struct gpio_chip         gc;
0028     void __iomem             *reg_base;
0029 };
0030
0031 static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
0032 {
0033     struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
0034     unsigned long flags;
0035     u32 using_pins;
0036
0037     dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
0038
0039     raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
0040
0041     using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
0042     if (using_pins & BIT(offset)) {
0043         dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
0044              offset);
0045         raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
0046         return -EINVAL;
0047     }
0048
0049     writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
0050
0051     raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
0052
0053     return 0;
0054 }
0055
0056 static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
0057 {
0058     struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
0059     unsigned long flags;
0060     u32 using_pins;
0061
0062     raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
0063
0064     using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
0065     using_pins &= ~BIT(offset);
0066     writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
0067
0068     raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
0069
0070     dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
0071 }
0072
0073 static int pt_gpio_probe(struct platform_device *pdev)
0074 {
0075     struct device *dev = &pdev->dev;
0076     struct pt_gpio_chip *pt_gpio;
0077     int ret = 0;
0078
0079     if (!ACPI_COMPANION(dev)) {
0080         dev_err(dev, "PT GPIO device node not found\n");
0081         return -ENODEV;
0082     }
0083
0084     pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
0085     if (!pt_gpio)
0086         return -ENOMEM;
0087
0088     pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
0089     if (IS_ERR(pt_gpio->reg_base)) {
0090         dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
0091         return PTR_ERR(pt_gpio->reg_base);
0092     }
0093
0094     ret = bgpio_init(&pt_gpio->gc, dev, 4,
0095              pt_gpio->reg_base + PT_INPUTDATA_REG,
0096              pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
0097              pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
0098              BGPIOF_READ_OUTPUT_REG_SET);
0099     if (ret) {
0100         dev_err(dev, "bgpio_init failed\n");
0101         return ret;
0102     }
0103
0104     pt_gpio->gc.owner            = THIS_MODULE;
0105     pt_gpio->gc.request          = pt_gpio_request;
0106     pt_gpio->gc.free             = pt_gpio_free;
0107     pt_gpio->gc.ngpio            = (uintptr_t)device_get_match_data(dev);
0108
0109     ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
0110     if (ret) {
0111         dev_err(dev, "Failed to register GPIO lib\n");
0112         return ret;
0113     }
0114
0115     platform_set_drvdata(pdev, pt_gpio);
0116
0117     /* initialize register setting */
0118     writel(0, pt_gpio->reg_base + PT_SYNC_REG);
0119     writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
0120
0121     dev_dbg(dev, "PT GPIO driver loaded\n");
0122     return ret;
0123 }
0124
0125 static int pt_gpio_remove(struct platform_device *pdev)
0126 {
0127     struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
0128
0129     gpiochip_remove(&pt_gpio->gc);
0130
0131     return 0;
0132 }
0133
0134 static const struct acpi_device_id pt_gpio_acpi_match[] = {
0135     { "AMDF030", PT_TOTAL_GPIO },
0136     { "AMDIF030", PT_TOTAL_GPIO },
0137     { "AMDIF031", PT_TOTAL_GPIO_EX },
0138     { },
0139 };
0140 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
0141
0142 static struct platform_driver pt_gpio_driver = {
0143     .driver = {
0144         .name = "pt-gpio",
0145         .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
0146     },
0147     .probe = pt_gpio_probe,
0148     .remove = pt_gpio_remove,
0149 };
0150
0151 module_platform_driver(pt_gpio_driver);
0152
0153 MODULE_LICENSE("GPL");
0154 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
0155 MODULE_DESCRIPTION("AMD Promontory GPIO Driver");