drivers/gpio/gpio-octeon.c

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

File Facts

System
Linux kernel
Corpus path
drivers/gpio/gpio-octeon.c
Extension
.c
Size
3302 bytes
Lines
141
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 octeon_gpio {
	struct gpio_chip chip;
	u64 register_base;
};

static int octeon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
{
	struct octeon_gpio *gpio = gpiochip_get_data(chip);

	cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), 0);
	return 0;
}

static int octeon_gpio_set(struct gpio_chip *chip, unsigned int offset,
			   int value)
{
	struct octeon_gpio *gpio = gpiochip_get_data(chip);
	u64 mask = 1ull << offset;
	u64 reg = gpio->register_base + (value ? TX_SET : TX_CLEAR);
	cvmx_write_csr(reg, mask);

	return 0;
}

static int octeon_gpio_dir_out(struct gpio_chip *chip, unsigned offset,
			       int value)
{
	struct octeon_gpio *gpio = gpiochip_get_data(chip);
	union cvmx_gpio_bit_cfgx cfgx;

	octeon_gpio_set(chip, offset, value);

	cfgx.u64 = 0;
	cfgx.s.tx_oe = 1;

	cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), cfgx.u64);
	return 0;
}

static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct octeon_gpio *gpio = gpiochip_get_data(chip);
	u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT);

	return ((1ull << offset) & read_bits) != 0;
}

static int octeon_gpio_probe(struct platform_device *pdev)
{
	struct octeon_gpio *gpio;
	struct gpio_chip *chip;
	void __iomem *reg_base;
	int err = 0;

	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
	if (!gpio)
		return -ENOMEM;
	chip = &gpio->chip;

	reg_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(reg_base))
		return PTR_ERR(reg_base);

	gpio->register_base = (u64)reg_base;
	pdev->dev.platform_data = chip;
	chip->label = "octeon-gpio";
	chip->parent = &pdev->dev;
	chip->owner = THIS_MODULE;
	chip->base = 0;
	chip->can_sleep = false;
	chip->ngpio = 20;
	chip->direction_input = octeon_gpio_dir_in;
	chip->get = octeon_gpio_get;
	chip->direction_output = octeon_gpio_dir_out;
	chip->set = octeon_gpio_set;
	err = devm_gpiochip_add_data(&pdev->dev, chip, gpio);
	if (err)
		return err;

	dev_info(&pdev->dev, "OCTEON GPIO driver probed.\n");
	return 0;
}

static const struct of_device_id octeon_gpio_match[] = {
	{
		.compatible = "cavium,octeon-3860-gpio",
	},
	{},
};
MODULE_DEVICE_TABLE(of, octeon_gpio_match);

Annotation

Implementation Notes