drivers/clk/at91/clk-utmi.c

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

File Facts

System
Linux kernel
Corpus path
drivers/clk/at91/clk-utmi.c
Extension
.c
Size
6448 bytes
Lines
295
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 clk_utmi {
	struct clk_hw hw;
	struct regmap *regmap_pmc;
	struct regmap *regmap_sfr;
	struct at91_clk_pms pms;
};

#define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)

static inline bool clk_utmi_ready(struct regmap *regmap)
{
	unsigned int status;

	regmap_read(regmap, AT91_PMC_SR, &status);

	return status & AT91_PMC_LOCKU;
}

static int clk_utmi_prepare(struct clk_hw *hw)
{
	struct clk_hw *hw_parent;
	struct clk_utmi *utmi = to_clk_utmi(hw);
	unsigned int uckr = AT91_PMC_UPLLEN | AT91_PMC_UPLLCOUNT |
			    AT91_PMC_BIASEN;
	unsigned int utmi_ref_clk_freq;
	unsigned long parent_rate;

	/*
	 * If mainck rate is different from 12 MHz, we have to configure the
	 * FREQ field of the SFR_UTMICKTRIM register to generate properly
	 * the utmi clock.
	 */
	hw_parent = clk_hw_get_parent(hw);
	parent_rate = clk_hw_get_rate(hw_parent);

	switch (parent_rate) {
	case 12000000:
		utmi_ref_clk_freq = 0;
		break;
	case 16000000:
		utmi_ref_clk_freq = 1;
		break;
	case 24000000:
		utmi_ref_clk_freq = 2;
		break;
	/*
	 * Not supported on SAMA5D2 but it's not an issue since MAINCK
	 * maximum value is 24 MHz.
	 */
	case 48000000:
		utmi_ref_clk_freq = 3;
		break;
	default:
		pr_err("UTMICK: unsupported mainck rate\n");
		return -EINVAL;
	}

	if (utmi->regmap_sfr) {
		regmap_update_bits(utmi->regmap_sfr, AT91_SFR_UTMICKTRIM,
				   AT91_UTMICKTRIM_FREQ, utmi_ref_clk_freq);
	} else if (utmi_ref_clk_freq) {
		pr_err("UTMICK: sfr node required\n");
		return -EINVAL;
	}

	regmap_update_bits(utmi->regmap_pmc, AT91_CKGR_UCKR, uckr, uckr);

	while (!clk_utmi_ready(utmi->regmap_pmc))
		cpu_relax();

	return 0;
}

static int clk_utmi_is_prepared(struct clk_hw *hw)
{
	struct clk_utmi *utmi = to_clk_utmi(hw);

	return clk_utmi_ready(utmi->regmap_pmc);
}

static void clk_utmi_unprepare(struct clk_hw *hw)
{
	struct clk_utmi *utmi = to_clk_utmi(hw);

	regmap_update_bits(utmi->regmap_pmc, AT91_CKGR_UCKR,
			   AT91_PMC_UPLLEN, 0);
}

static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
					  unsigned long parent_rate)

Annotation

Implementation Notes