drivers/clk/actions/owl-factor.c

Source file repositories/reference/linux-study-clean/drivers/clk/actions/owl-factor.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/actions/owl-factor.c
Extension
.c
Size
5672 bytes
Lines
223
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

if (clkt->val == val) {
			*mul = clkt->mul;
			*div = clkt->div;
			return 1;
		}
	}

	return 0;
}

static unsigned int _get_table_val(const struct clk_factor_table *table,
			unsigned long rate, unsigned long parent_rate)
{
	const struct clk_factor_table *clkt;
	int val = -1;
	u64 calc_rate;

	for (clkt = table; clkt->div; clkt++) {
		calc_rate = parent_rate * clkt->mul;
		do_div(calc_rate, clkt->div);

		if ((unsigned long)calc_rate <= rate) {
			val = clkt->val;
			break;
		}
	}

	if (val == -1)
		val = _get_table_maxval(table);

	return val;
}

static int owl_clk_val_best(const struct owl_factor_hw *factor_hw,
			struct clk_hw *hw, unsigned long rate,
			unsigned long *best_parent_rate)
{
	const struct clk_factor_table *clkt = factor_hw->table;
	unsigned long parent_rate, try_parent_rate, best = 0, cur_rate;
	unsigned long parent_rate_saved = *best_parent_rate;
	int bestval = 0;

	if (!rate)
		rate = 1;

	if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
		parent_rate = *best_parent_rate;
		bestval = _get_table_val(clkt, rate, parent_rate);
		return bestval;
	}

	for (clkt = factor_hw->table; clkt->div; clkt++) {
		try_parent_rate = rate * clkt->div / clkt->mul;

		if (try_parent_rate == parent_rate_saved) {
			pr_debug("%s: [%d %d %d] found try_parent_rate %ld\n",
				__func__, clkt->val, clkt->mul, clkt->div,
				try_parent_rate);
			/*
			 * It's the most ideal case if the requested rate can be
			 * divided from parent clock without any need to change
			 * parent rate, so return the divider immediately.
			 */
			*best_parent_rate = parent_rate_saved;
			return clkt->val;
		}

		parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
				try_parent_rate);
		cur_rate = DIV_ROUND_UP(parent_rate, clkt->div) * clkt->mul;
		if (cur_rate <= rate && cur_rate > best) {
			bestval = clkt->val;
			best = cur_rate;
			*best_parent_rate = parent_rate;
		}
	}

	if (!bestval) {
		bestval = _get_table_maxval(clkt);
		*best_parent_rate = clk_hw_round_rate(
				clk_hw_get_parent(hw), 1);
	}

	return bestval;
}

long owl_factor_helper_round_rate(struct owl_clk_common *common,
				const struct owl_factor_hw *factor_hw,
				unsigned long rate,
				unsigned long *parent_rate)

Annotation

Implementation Notes