drivers/clk/stm32/reset-stm32.c

Source file repositories/reference/linux-study-clean/drivers/clk/stm32/reset-stm32.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/stm32/reset-stm32.c
Extension
.c
Size
3651 bytes
Lines
149
Domain
Driver Families
Bucket
drivers/clk
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 stm32_reset_data {
	/* reset lock */
	spinlock_t			lock;
	struct reset_controller_dev	rcdev;
	void __iomem			*membase;
	u32				clear_offset;
	const struct stm32_reset_cfg	**reset_lines;
};

static inline struct stm32_reset_data *
to_stm32_reset_data(struct reset_controller_dev *rcdev)
{
	return container_of(rcdev, struct stm32_reset_data, rcdev);
}

static const struct stm32_reset_cfg *stm32_get_reset_line(struct reset_controller_dev *rcdev,
							  unsigned long id,
							  struct stm32_reset_cfg *line)
{
	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);

	if (!data->reset_lines) {
		int reg_width = sizeof(u32);
		int bank = id / (reg_width * BITS_PER_BYTE);
		int offset = id % (reg_width * BITS_PER_BYTE);

		line->offset = bank * reg_width;
		line->bit_idx = offset;
		line->set_clr = (data->clear_offset ? true : false);

		return line;
	}

	return data->reset_lines[id];
}

static int stm32_reset_update(struct reset_controller_dev *rcdev,
			      unsigned long id, bool assert)
{
	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
	struct stm32_reset_cfg line_reset;
	const struct stm32_reset_cfg *ptr_line;

	ptr_line = stm32_get_reset_line(rcdev, id, &line_reset);
	if (!ptr_line)
		return -EPERM;

	if (ptr_line->set_clr) {
		void __iomem *addr;

		addr = data->membase + ptr_line->offset;
		if (!assert)
			addr += data->clear_offset;

		writel(BIT(ptr_line->bit_idx), addr);

	} else {
		unsigned long flags;
		u32 reg;

		spin_lock_irqsave(&data->lock, flags);

		reg = readl(data->membase + ptr_line->offset);

		if (assert)
			reg |= BIT(ptr_line->bit_idx);
		else
			reg &= ~BIT(ptr_line->bit_idx);

		writel(reg, data->membase + ptr_line->offset);

		spin_unlock_irqrestore(&data->lock, flags);
	}

	return 0;
}

static int stm32_reset_assert(struct reset_controller_dev *rcdev,
			      unsigned long id)
{
	return stm32_reset_update(rcdev, id, true);
}

static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
				unsigned long id)
{
	return stm32_reset_update(rcdev, id, false);
}

static int stm32_reset_status(struct reset_controller_dev *rcdev,

Annotation

Implementation Notes