drivers/clk/imx/clk-pfd.c

Source file repositories/reference/linux-study-clean/drivers/clk/imx/clk-pfd.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/imx/clk-pfd.c
Extension
.c
Size
3223 bytes
Lines
160
Domain
Driver Families
Bucket
drivers/clk
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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_pfd {
	struct clk_hw	hw;
	void __iomem	*reg;
	u8		idx;
};

#define to_clk_pfd(_hw) container_of(_hw, struct clk_pfd, hw)

#define SET	0x4
#define CLR	0x8
#define OTG	0xc

static int clk_pfd_enable(struct clk_hw *hw)
{
	struct clk_pfd *pfd = to_clk_pfd(hw);

	writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + CLR);

	return 0;
}

static void clk_pfd_disable(struct clk_hw *hw)
{
	struct clk_pfd *pfd = to_clk_pfd(hw);

	writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + SET);
}

static unsigned long clk_pfd_recalc_rate(struct clk_hw *hw,
					 unsigned long parent_rate)
{
	struct clk_pfd *pfd = to_clk_pfd(hw);
	u64 tmp = parent_rate;
	u8 frac = (readl_relaxed(pfd->reg) >> (pfd->idx * 8)) & 0x3f;

	tmp *= 18;
	do_div(tmp, frac);

	return tmp;
}

static int clk_pfd_determine_rate(struct clk_hw *hw,
				  struct clk_rate_request *req)
{
	u64 tmp = req->best_parent_rate;
	u8 frac;

	tmp = tmp * 18 + req->rate / 2;
	do_div(tmp, req->rate);
	frac = tmp;
	if (frac < 12)
		frac = 12;
	else if (frac > 35)
		frac = 35;
	tmp = req->best_parent_rate;
	tmp *= 18;
	do_div(tmp, frac);

	req->rate = tmp;

	return 0;
}

static int clk_pfd_set_rate(struct clk_hw *hw, unsigned long rate,
		unsigned long parent_rate)
{
	struct clk_pfd *pfd = to_clk_pfd(hw);
	u64 tmp = parent_rate;
	u8 frac;

	tmp = tmp * 18 + rate / 2;
	do_div(tmp, rate);
	frac = tmp;
	if (frac < 12)
		frac = 12;
	else if (frac > 35)
		frac = 35;

	writel_relaxed(0x3f << (pfd->idx * 8), pfd->reg + CLR);
	writel_relaxed(frac << (pfd->idx * 8), pfd->reg + SET);

	return 0;
}

static int clk_pfd_is_enabled(struct clk_hw *hw)
{
	struct clk_pfd *pfd = to_clk_pfd(hw);

	if (readl_relaxed(pfd->reg) & (1 << ((pfd->idx + 1) * 8 - 1)))
		return 0;

Annotation

Implementation Notes