drivers/clk/qcom/clk-rcg2.c

Source file repositories/reference/linux-study-clean/drivers/clk/qcom/clk-rcg2.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/qcom/clk-rcg2.c
Extension
.c
Size
46477 bytes
Lines
1862
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 frac_entry {
	int num;
	int den;
};

static const struct frac_entry frac_table_675m[] = {	/* link rate of 270M */
	{ 52, 295 },	/* 119 M */
	{ 11, 57 },	/* 130.25 M */
	{ 63, 307 },	/* 138.50 M */
	{ 11, 50 },	/* 148.50 M */
	{ 47, 206 },	/* 154 M */
	{ 31, 100 },	/* 205.25 M */
	{ 107, 269 },	/* 268.50 M */
	{ },
};

static struct frac_entry frac_table_810m[] = { /* Link rate of 162M */
	{ 31, 211 },	/* 119 M */
	{ 32, 199 },	/* 130.25 M */
	{ 63, 307 },	/* 138.50 M */
	{ 11, 60 },	/* 148.50 M */
	{ 50, 263 },	/* 154 M */
	{ 31, 120 },	/* 205.25 M */
	{ 119, 359 },	/* 268.50 M */
	{ },
};

static int clk_edp_pixel_set_rate(struct clk_hw *hw, unsigned long rate,
			      unsigned long parent_rate)
{
	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
	struct freq_tbl f = *rcg->freq_tbl;
	const struct frac_entry *frac;
	int delta = 100000;
	s64 src_rate = parent_rate;
	s64 request;
	u32 mask = BIT(rcg->hid_width) - 1;
	u32 hid_div;

	if (src_rate == 810000000)
		frac = frac_table_810m;
	else
		frac = frac_table_675m;

	for (; frac->num; frac++) {
		request = rate;
		request *= frac->den;
		request = div_s64(request, frac->num);
		if ((src_rate < (request - delta)) ||
		    (src_rate > (request + delta)))
			continue;

		regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG,
				&hid_div);
		f.pre_div = hid_div;
		f.pre_div >>= CFG_SRC_DIV_SHIFT;
		f.pre_div &= mask;
		f.m = frac->num;
		f.n = frac->den;

		return clk_rcg2_configure(rcg, &f);
	}

	return -EINVAL;
}

static int clk_edp_pixel_set_rate_and_parent(struct clk_hw *hw,
		unsigned long rate, unsigned long parent_rate, u8 index)
{
	/* Parent index is set statically in frequency table */
	return clk_edp_pixel_set_rate(hw, rate, parent_rate);
}

static int clk_edp_pixel_determine_rate(struct clk_hw *hw,
					struct clk_rate_request *req)
{
	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
	const struct freq_tbl *f = rcg->freq_tbl;
	const struct frac_entry *frac;
	int delta = 100000;
	s64 request;
	u32 mask = BIT(rcg->hid_width) - 1;
	u32 hid_div;
	int index = qcom_find_src_index(hw, rcg->parent_map, f->src);

	/* Force the correct parent */
	req->best_parent_hw = clk_hw_get_parent_by_index(hw, index);
	req->best_parent_rate = clk_hw_get_rate(req->best_parent_hw);

	if (req->best_parent_rate == 810000000)

Annotation

Implementation Notes