drivers/gpio/gpio-zevio.c

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

File Facts

System
Linux kernel
Corpus path
drivers/gpio/gpio-zevio.c
Extension
.c
Size
6194 bytes
Lines
227
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 zevio_gpio {
	struct gpio_chip        chip;
	spinlock_t		lock;
	void __iomem		*regs;
};

static inline u32 zevio_gpio_port_get(struct zevio_gpio *c, unsigned pin,
					unsigned port_offset)
{
	unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE;
	return readl(c->regs + section_offset + port_offset);
}

static inline void zevio_gpio_port_set(struct zevio_gpio *c, unsigned pin,
					unsigned port_offset, u32 val)
{
	unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE;
	writel(val, c->regs + section_offset + port_offset);
}

/* Functions for struct gpio_chip */
static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin)
{
	struct zevio_gpio *controller = gpiochip_get_data(chip);
	u32 val, dir;

	spin_lock(&controller->lock);
	dir = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
	if (dir & BIT(ZEVIO_GPIO_BIT(pin)))
		val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT);
	else
		val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
	spin_unlock(&controller->lock);

	return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1;
}

static int zevio_gpio_set(struct gpio_chip *chip, unsigned int pin, int value)
{
	struct zevio_gpio *controller = gpiochip_get_data(chip);
	u32 val;

	spin_lock(&controller->lock);
	val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
	if (value)
		val |= BIT(ZEVIO_GPIO_BIT(pin));
	else
		val &= ~BIT(ZEVIO_GPIO_BIT(pin));

	zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val);
	spin_unlock(&controller->lock);

	return 0;
}

static int zevio_gpio_direction_input(struct gpio_chip *chip, unsigned pin)
{
	struct zevio_gpio *controller = gpiochip_get_data(chip);
	u32 val;

	spin_lock(&controller->lock);

	val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
	val |= BIT(ZEVIO_GPIO_BIT(pin));
	zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val);

	spin_unlock(&controller->lock);

	return 0;
}

static int zevio_gpio_direction_output(struct gpio_chip *chip,
				       unsigned pin, int value)
{
	struct zevio_gpio *controller = gpiochip_get_data(chip);
	u32 val;

	spin_lock(&controller->lock);
	val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT);
	if (value)
		val |= BIT(ZEVIO_GPIO_BIT(pin));
	else
		val &= ~BIT(ZEVIO_GPIO_BIT(pin));

	zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val);
	val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION);
	val &= ~BIT(ZEVIO_GPIO_BIT(pin));
	zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val);

	spin_unlock(&controller->lock);

Annotation

Implementation Notes