drivers/clk/bcm/clk-bcm53573-ilp.c

Source file repositories/reference/linux-study-clean/drivers/clk/bcm/clk-bcm53573-ilp.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/bcm/clk-bcm53573-ilp.c
Extension
.c
Size
3428 bytes
Lines
146
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 bcm53573_ilp {
	struct clk_hw hw;
	struct regmap *regmap;
};

static int bcm53573_ilp_enable(struct clk_hw *hw)
{
	struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);

	regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0x10199);
	regmap_write(ilp->regmap, 0x674, 0x10000);

	return 0;
}

static void bcm53573_ilp_disable(struct clk_hw *hw)
{
	struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);

	regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0);
	regmap_write(ilp->regmap, 0x674, 0);
}

static unsigned long bcm53573_ilp_recalc_rate(struct clk_hw *hw,
					      unsigned long parent_rate)
{
	struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
	struct regmap *regmap = ilp->regmap;
	u32 last_val, cur_val;
	int sum = 0, num = 0, loop_num = 0;
	int avg;

	/* Enable measurement */
	regmap_write(regmap, PMU_XTAL_FREQ_RATIO, XTAL_CTL_EN);

	/* Read initial value */
	regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &last_val);
	last_val &= XTAL_ALP_PER_4ILP;

	/*
	 * At minimum we should loop for a bit to let hardware do the
	 * measurement. This isn't very accurate however, so for a better
	 * precision let's try getting 20 different values and use average.
	 */
	while (num < 20) {
		regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &cur_val);
		cur_val &= XTAL_ALP_PER_4ILP;

		if (cur_val != last_val) {
			/* Got different value, use it */
			sum += cur_val;
			num++;
			loop_num = 0;
			last_val = cur_val;
		} else if (++loop_num > 5000) {
			/* Same value over and over, give up */
			sum += cur_val;
			num++;
			break;
		}

		cpu_relax();
	}

	/* Disable measurement to save power */
	regmap_write(regmap, PMU_XTAL_FREQ_RATIO, 0x0);

	avg = sum / num;

	return parent_rate * 4 / avg;
}

static const struct clk_ops bcm53573_ilp_clk_ops = {
	.enable = bcm53573_ilp_enable,
	.disable = bcm53573_ilp_disable,
	.recalc_rate = bcm53573_ilp_recalc_rate,
};

static void bcm53573_ilp_init(struct device_node *np)
{
	struct bcm53573_ilp *ilp;
	struct clk_init_data init = { };
	const char *parent_name;
	int err;

	ilp = kzalloc_obj(*ilp);
	if (!ilp)
		return;

	parent_name = of_clk_get_parent_name(np, 0);

Annotation

Implementation Notes