drivers/gpio/gpio-logicvc.c

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

File Facts

System
Linux kernel
Corpus path
drivers/gpio/gpio-logicvc.c
Extension
.c
Size
4174 bytes
Lines
165
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 logicvc_gpio {
	struct gpio_chip chip;
	struct regmap *regmap;
};

static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
				unsigned int *reg, unsigned int *bit)
{
	if (offset >= LOGICVC_CTRL_GPIO_BITS) {
		*reg = LOGICVC_POWER_CTRL_REG;

		/* To the (virtual) power ctrl offset. */
		offset -= LOGICVC_CTRL_GPIO_BITS;
		/* To the actual bit offset in reg. */
		offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
	} else {
		*reg = LOGICVC_CTRL_REG;

		/* To the actual bit offset in reg. */
		offset += LOGICVC_CTRL_GPIO_SHIFT;
	}

	*bit = BIT(offset);
}

static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
	unsigned int reg, bit, value;
	int ret;

	logicvc_gpio_offset(logicvc, offset, &reg, &bit);

	ret = regmap_read(logicvc->regmap, reg, &value);
	if (ret)
		return ret;

	return !!(value & bit);
}

static int logicvc_gpio_set(struct gpio_chip *chip, unsigned int offset,
			    int value)
{
	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
	unsigned int reg, bit;

	logicvc_gpio_offset(logicvc, offset, &reg, &bit);

	return regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
}

static int logicvc_gpio_direction_output(struct gpio_chip *chip,
					 unsigned offset, int value)
{
	/* Pins are always configured as output, so just set the value. */
	return logicvc_gpio_set(chip, offset, value);
}

static struct regmap_config logicvc_gpio_regmap_config = {
	.reg_bits	= 32,
	.val_bits	= 32,
	.reg_stride	= 4,
	.name		= "logicvc-gpio",
};

static int logicvc_gpio_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *of_node = dev->of_node;
	struct logicvc_gpio *logicvc;
	int ret;

	logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
	if (!logicvc)
		return -ENOMEM;

	/* Try to get regmap from parent first. */
	logicvc->regmap = syscon_node_to_regmap(of_node->parent);

	/* Grab our own regmap if that fails. */
	if (IS_ERR(logicvc->regmap)) {
		struct resource res;
		void __iomem *base;

		ret = of_address_to_resource(of_node, 0, &res);
		if (ret) {
			dev_err(dev, "Failed to get resource from address\n");
			return ret;
		}

Annotation

Implementation Notes