diff options
Diffstat (limited to 'drivers/gpio/gpio-amdpt.c')
| -rw-r--r-- | drivers/gpio/gpio-amdpt.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-amdpt.c b/drivers/gpio/gpio-amdpt.c new file mode 100644 index 000000000..9b78dc837 --- /dev/null +++ b/drivers/gpio/gpio-amdpt.c @@ -0,0 +1,166 @@ +/* + * AMD Promontory GPIO driver + * + * Copyright (C) 2015 ASMedia Technology Inc. + * Author: YD Tseng <yd_tseng@asmedia.com.tw> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/gpio/driver.h> +#include <linux/spinlock.h> +#include <linux/acpi.h> +#include <linux/platform_device.h> + +#define PT_TOTAL_GPIO 8 + +/* PCI-E MMIO register offsets */ +#define PT_DIRECTION_REG 0x00 +#define PT_INPUTDATA_REG 0x04 +#define PT_OUTPUTDATA_REG 0x08 +#define PT_CLOCKRATE_REG 0x0C +#define PT_SYNC_REG 0x28 + +struct pt_gpio_chip { + struct gpio_chip gc; + void __iomem *reg_base; +}; + +static int pt_gpio_request(struct gpio_chip *gc, unsigned offset) +{ + struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc); + unsigned long flags; + u32 using_pins; + + dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset); + + spin_lock_irqsave(&gc->bgpio_lock, flags); + + using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG); + if (using_pins & BIT(offset)) { + dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n", + offset); + spin_unlock_irqrestore(&gc->bgpio_lock, flags); + return -EINVAL; + } + + writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG); + + spin_unlock_irqrestore(&gc->bgpio_lock, flags); + + return 0; +} + +static void pt_gpio_free(struct gpio_chip *gc, unsigned offset) +{ + struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc); + unsigned long flags; + u32 using_pins; + + spin_lock_irqsave(&gc->bgpio_lock, flags); + + using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG); + using_pins &= ~BIT(offset); + writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG); + + spin_unlock_irqrestore(&gc->bgpio_lock, flags); + + dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset); +} + +static int pt_gpio_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct acpi_device *acpi_dev; + acpi_handle handle = ACPI_HANDLE(dev); + struct pt_gpio_chip *pt_gpio; + struct resource *res_mem; + int ret = 0; + + if (acpi_bus_get_device(handle, &acpi_dev)) { + dev_err(dev, "PT GPIO device node not found\n"); + return -ENODEV; + } + + pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL); + if (!pt_gpio) + return -ENOMEM; + + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res_mem) { + dev_err(&pdev->dev, "Failed to get MMIO resource for PT GPIO.\n"); + return -EINVAL; + } + pt_gpio->reg_base = devm_ioremap_resource(dev, res_mem); + if (IS_ERR(pt_gpio->reg_base)) { + dev_err(&pdev->dev, "Failed to map MMIO resource for PT GPIO.\n"); + return PTR_ERR(pt_gpio->reg_base); + } + + ret = bgpio_init(&pt_gpio->gc, dev, 4, + pt_gpio->reg_base + PT_INPUTDATA_REG, + pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL, + pt_gpio->reg_base + PT_DIRECTION_REG, NULL, + BGPIOF_READ_OUTPUT_REG_SET); + if (ret) { + dev_err(&pdev->dev, "bgpio_init failed\n"); + return ret; + } + + pt_gpio->gc.owner = THIS_MODULE; + pt_gpio->gc.request = pt_gpio_request; + pt_gpio->gc.free = pt_gpio_free; + pt_gpio->gc.ngpio = PT_TOTAL_GPIO; +#if defined(CONFIG_OF_GPIO) + pt_gpio->gc.of_node = pdev->dev.of_node; +#endif + ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio); + if (ret) { + dev_err(&pdev->dev, "Failed to register GPIO lib\n"); + return ret; + } + + platform_set_drvdata(pdev, pt_gpio); + + /* initialize register setting */ + writel(0, pt_gpio->reg_base + PT_SYNC_REG); + writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG); + + dev_dbg(&pdev->dev, "PT GPIO driver loaded\n"); + return ret; +} + +static int pt_gpio_remove(struct platform_device *pdev) +{ + struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev); + + gpiochip_remove(&pt_gpio->gc); + + return 0; +} + +static const struct acpi_device_id pt_gpio_acpi_match[] = { + { "AMDF030", 0 }, + { "AMDIF030", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match); + +static struct platform_driver pt_gpio_driver = { + .driver = { + .name = "pt-gpio", + .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match), + }, + .probe = pt_gpio_probe, + .remove = pt_gpio_remove, +}; + +module_platform_driver(pt_gpio_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>"); +MODULE_DESCRIPTION("AMD Promontory GPIO Driver"); |