drivers/clk/mmp/clk-apbc.c

Source file repositories/reference/linux-study-clean/drivers/clk/mmp/clk-apbc.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/mmp/clk-apbc.c
Extension
.c
Size
3247 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 clk_apbc {
	struct clk_hw		hw;
	void __iomem		*base;
	unsigned int		delay;
	unsigned int		flags;
	spinlock_t		*lock;
};

static int clk_apbc_prepare(struct clk_hw *hw)
{
	struct clk_apbc *apbc = to_clk_apbc(hw);
	unsigned int data;
	unsigned long flags = 0;

	/*
	 * It may share same register as MUX clock,
	 * and it will impact FNCLK enable. Spinlock is needed
	 */
	if (apbc->lock)
		spin_lock_irqsave(apbc->lock, flags);

	data = readl_relaxed(apbc->base);
	if (apbc->flags & APBC_POWER_CTRL)
		data |= APBC_POWER;
	data |= APBC_FNCLK;
	writel_relaxed(data, apbc->base);

	if (apbc->lock)
		spin_unlock_irqrestore(apbc->lock, flags);

	udelay(apbc->delay);

	if (apbc->lock)
		spin_lock_irqsave(apbc->lock, flags);

	data = readl_relaxed(apbc->base);
	data |= APBC_APBCLK;
	writel_relaxed(data, apbc->base);

	if (apbc->lock)
		spin_unlock_irqrestore(apbc->lock, flags);

	udelay(apbc->delay);

	if (!(apbc->flags & APBC_NO_BUS_CTRL)) {
		if (apbc->lock)
			spin_lock_irqsave(apbc->lock, flags);

		data = readl_relaxed(apbc->base);
		data &= ~APBC_RST;
		writel_relaxed(data, apbc->base);

		if (apbc->lock)
			spin_unlock_irqrestore(apbc->lock, flags);
	}

	return 0;
}

static void clk_apbc_unprepare(struct clk_hw *hw)
{
	struct clk_apbc *apbc = to_clk_apbc(hw);
	unsigned long data;
	unsigned long flags = 0;

	if (apbc->lock)
		spin_lock_irqsave(apbc->lock, flags);

	data = readl_relaxed(apbc->base);
	if (apbc->flags & APBC_POWER_CTRL)
		data &= ~APBC_POWER;
	data &= ~APBC_FNCLK;
	writel_relaxed(data, apbc->base);

	if (apbc->lock)
		spin_unlock_irqrestore(apbc->lock, flags);

	udelay(10);

	if (apbc->lock)
		spin_lock_irqsave(apbc->lock, flags);

	data = readl_relaxed(apbc->base);
	data &= ~APBC_APBCLK;
	writel_relaxed(data, apbc->base);

	if (apbc->lock)
		spin_unlock_irqrestore(apbc->lock, flags);
}

Annotation

Implementation Notes