drivers/gpio/gpio-graniterapids.c

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

File Facts

System
Linux kernel
Corpus path
drivers/gpio/gpio-graniterapids.c
Extension
.c
Size
10806 bytes
Lines
416
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 gnr_gpio {
	struct gpio_chip gc;
	void __iomem *reg_base;
	void __iomem *pad_base;
	DECLARE_BITMAP(ro_bitmap, GNR_NUM_PINS);
	raw_spinlock_t lock;
	u32 pad_backup[];
};

static void __iomem *gnr_gpio_get_padcfg_addr(const struct gnr_gpio *priv,
					      unsigned int gpio)
{
	return priv->pad_base + gpio * sizeof(u32);
}

static int gnr_gpio_configure_line(struct gpio_chip *gc, unsigned int gpio,
				   u32 clear_mask, u32 set_mask)
{
	struct gnr_gpio *priv = gpiochip_get_data(gc);
	void __iomem *addr = gnr_gpio_get_padcfg_addr(priv, gpio);
	u32 dw;

	if (test_bit(gpio, priv->ro_bitmap))
		return -EACCES;

	guard(raw_spinlock_irqsave)(&priv->lock);

	dw = readl(addr);
	dw &= ~clear_mask;
	dw |= set_mask;
	writel(dw, addr);

	return 0;
}

static int gnr_gpio_request(struct gpio_chip *gc, unsigned int gpio)
{
	struct gnr_gpio *priv = gpiochip_get_data(gc);
	u32 dw;

	dw = readl(gnr_gpio_get_padcfg_addr(priv, gpio));
	if (!(dw & GNR_CFG_DW_HOSTSW_MODE)) {
		dev_warn(gc->parent, "GPIO %u is not owned by host", gpio);
		return -EBUSY;
	}

	return 0;
}

static int gnr_gpio_get(struct gpio_chip *gc, unsigned int gpio)
{
	const struct gnr_gpio *priv = gpiochip_get_data(gc);
	u32 dw;

	dw = readl(gnr_gpio_get_padcfg_addr(priv, gpio));

	return !!(dw & GNR_CFG_DW_RXSTATE);
}

static int gnr_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
{
	u32 clear = 0;
	u32 set = 0;

	if (value)
		set = GNR_CFG_DW_TXSTATE;
	else
		clear = GNR_CFG_DW_TXSTATE;

	return gnr_gpio_configure_line(gc, gpio, clear, set);
}

static int gnr_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
{
	struct gnr_gpio *priv = gpiochip_get_data(gc);
	u32 dw;

	dw = readl(gnr_gpio_get_padcfg_addr(priv, gpio));

	if (dw & GNR_CFG_DW_TXDIS)
		return GPIO_LINE_DIRECTION_IN;

	return GPIO_LINE_DIRECTION_OUT;
}

static int gnr_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
{
	return gnr_gpio_configure_line(gc, gpio, GNR_CFG_DW_RXDIS, 0);
}

Annotation

Implementation Notes