drivers/clk/sunxi-ng/ccu_mult.c

Source file repositories/reference/linux-study-clean/drivers/clk/sunxi-ng/ccu_mult.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/sunxi-ng/ccu_mult.c
Extension
.c
Size
4087 bytes
Lines
174
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 _ccu_mult {
	unsigned long	mult, min, max;
};

static void ccu_mult_find_best(unsigned long parent, unsigned long rate,
			       struct _ccu_mult *mult)
{
	int _mult;

	_mult = rate / parent;
	if (_mult < mult->min)
		_mult = mult->min;

	if (_mult > mult->max)
		_mult = mult->max;

	mult->mult = _mult;
}

static int ccu_mult_determine_rate_helper(struct ccu_mux_internal *mux,
					  struct clk_rate_request *req,
					  void *data)
{
	struct ccu_mult *cm = data;
	struct _ccu_mult _cm;

	_cm.min = cm->mult.min;

	if (cm->mult.max)
		_cm.max = cm->mult.max;
	else
		_cm.max = (1 << cm->mult.width) + cm->mult.offset - 1;

	ccu_mult_find_best(req->best_parent_rate, req->rate, &_cm);

	req->rate = req->best_parent_rate * _cm.mult;

	return 0;
}

static void ccu_mult_disable(struct clk_hw *hw)
{
	struct ccu_mult *cm = hw_to_ccu_mult(hw);

	return ccu_gate_helper_disable(&cm->common, cm->enable);
}

static int ccu_mult_enable(struct clk_hw *hw)
{
	struct ccu_mult *cm = hw_to_ccu_mult(hw);

	return ccu_gate_helper_enable(&cm->common, cm->enable);
}

static int ccu_mult_is_enabled(struct clk_hw *hw)
{
	struct ccu_mult *cm = hw_to_ccu_mult(hw);

	return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
}

static unsigned long ccu_mult_recalc_rate(struct clk_hw *hw,
					unsigned long parent_rate)
{
	struct ccu_mult *cm = hw_to_ccu_mult(hw);
	unsigned long val;
	u32 reg;

	if (ccu_frac_helper_is_enabled(&cm->common, &cm->frac))
		return ccu_frac_helper_read_rate(&cm->common, &cm->frac);

	reg = readl(cm->common.base + cm->common.reg);
	val = reg >> cm->mult.shift;
	val &= (1 << cm->mult.width) - 1;

	parent_rate = ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
						  parent_rate);

	return parent_rate * (val + cm->mult.offset);
}

static int ccu_mult_determine_rate(struct clk_hw *hw,
				struct clk_rate_request *req)
{
	struct ccu_mult *cm = hw_to_ccu_mult(hw);

	return ccu_mux_helper_determine_rate(&cm->common, &cm->mux,
					     req, ccu_mult_determine_rate_helper, cm);
}

Annotation

Implementation Notes