drivers/gpio/gpio-amdpt.c

Source file repositories/reference/linux-study-clean/drivers/gpio/gpio-amdpt.c

File Facts

System
Linux kernel
Corpus path
drivers/gpio/gpio-amdpt.c
Extension
.c
Size
3844 bytes
Lines
148
Domain
Driver Families
Bucket
drivers/gpio
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct pt_gpio_chip {
	struct gpio_generic_chip chip;
	void __iomem             *reg_base;
};

static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
{
	struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc);
	struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
	u32 using_pins;

	dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);

	guard(gpio_generic_lock_irqsave)(gen_gc);

	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);
		return -EINVAL;
	}

	writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);

	return 0;
}

static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
{
	struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc);
	struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
	u32 using_pins;

	guard(gpio_generic_lock_irqsave)(gen_gc);

	using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
	using_pins &= ~BIT(offset);
	writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);

	dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
}

static int pt_gpio_probe(struct platform_device *pdev)
{
	struct gpio_generic_chip_config config;
	struct device *dev = &pdev->dev;
	struct pt_gpio_chip *pt_gpio;
	int ret = 0;

	if (!ACPI_COMPANION(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;

	pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(pt_gpio->reg_base)) {
		dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
		return PTR_ERR(pt_gpio->reg_base);
	}

	config = (struct gpio_generic_chip_config) {
		.dev = dev,
		.sz = 4,
		.dat = pt_gpio->reg_base + PT_INPUTDATA_REG,
		.set = pt_gpio->reg_base + PT_OUTPUTDATA_REG,
		.dirout = pt_gpio->reg_base + PT_DIRECTION_REG,
		.flags = GPIO_GENERIC_READ_OUTPUT_REG_SET,
	};

	ret = gpio_generic_chip_init(&pt_gpio->chip, &config);
	if (ret) {
		dev_err(dev, "failed to initialize the generic GPIO chip\n");
		return ret;
	}

	pt_gpio->chip.gc.owner = THIS_MODULE;
	pt_gpio->chip.gc.request = pt_gpio_request;
	pt_gpio->chip.gc.free = pt_gpio_free;
	pt_gpio->chip.gc.ngpio = (uintptr_t)device_get_match_data(dev);

	ret = devm_gpiochip_add_data(dev, &pt_gpio->chip.gc, pt_gpio);
	if (ret) {
		dev_err(dev, "Failed to register GPIO lib\n");
		return ret;
	}

Annotation

Implementation Notes