drivers/clk/at91/clk-smd.c

Source file repositories/reference/linux-study-clean/drivers/clk/at91/clk-smd.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/at91/clk-smd.c
Extension
.c
Size
3315 bytes
Lines
143
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 at91sam9x5_clk_smd {
	struct clk_hw hw;
	struct regmap *regmap;
};

#define to_at91sam9x5_clk_smd(hw) \
	container_of(hw, struct at91sam9x5_clk_smd, hw)

static unsigned long at91sam9x5_clk_smd_recalc_rate(struct clk_hw *hw,
						    unsigned long parent_rate)
{
	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
	unsigned int smdr;
	u8 smddiv;

	regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
	smddiv = (smdr & AT91_PMC_SMD_DIV) >> SMD_DIV_SHIFT;

	return parent_rate / (smddiv + 1);
}

static int at91sam9x5_clk_smd_determine_rate(struct clk_hw *hw,
					     struct clk_rate_request *req)
{
	unsigned long div;
	unsigned long bestrate;
	unsigned long tmp;

	if (req->rate >= req->best_parent_rate) {
		req->rate = req->best_parent_rate;
		return 0;
	}

	div = req->best_parent_rate / req->rate;
	if (div > SMD_MAX_DIV) {
		req->rate = req->best_parent_rate / (SMD_MAX_DIV + 1);
		return 0;
	}

	bestrate = req->best_parent_rate / div;
	tmp = req->best_parent_rate / (div + 1);
	if (bestrate - req->rate > req->rate - tmp)
		bestrate = tmp;

	req->rate = bestrate;
	return 0;
}

static int at91sam9x5_clk_smd_set_parent(struct clk_hw *hw, u8 index)
{
	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);

	if (index > 1)
		return -EINVAL;

	regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMDS,
			   index ? AT91_PMC_SMDS : 0);

	return 0;
}

static u8 at91sam9x5_clk_smd_get_parent(struct clk_hw *hw)
{
	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
	unsigned int smdr;

	regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);

	return smdr & AT91_PMC_SMDS;
}

static int at91sam9x5_clk_smd_set_rate(struct clk_hw *hw, unsigned long rate,
				       unsigned long parent_rate)
{
	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
	unsigned long div = parent_rate / rate;

	if (parent_rate % rate || div < 1 || div > (SMD_MAX_DIV + 1))
		return -EINVAL;

	regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMD_DIV,
			   (div - 1) << SMD_DIV_SHIFT);

	return 0;
}

static const struct clk_ops at91sam9x5_smd_ops = {
	.recalc_rate = at91sam9x5_clk_smd_recalc_rate,
	.determine_rate = at91sam9x5_clk_smd_determine_rate,
	.get_parent = at91sam9x5_clk_smd_get_parent,

Annotation

Implementation Notes