drivers/misc/qcom-coincell.c

Source file repositories/reference/linux-study-clean/drivers/misc/qcom-coincell.c

File Facts

System
Linux kernel
Corpus path
drivers/misc/qcom-coincell.c
Extension
.c
Size
3692 bytes
Lines
145
Domain
Driver Families
Bucket
drivers/misc
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 qcom_coincell {
	struct device	*dev;
	struct regmap	*regmap;
	u32		base_addr;
};

#define QCOM_COINCELL_REG_RSET		0x44
#define QCOM_COINCELL_REG_VSET		0x45
#define QCOM_COINCELL_REG_ENABLE	0x46

#define QCOM_COINCELL_ENABLE		BIT(7)

static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 };
static const int qcom_vset_map[] = { 2500, 3200, 3100, 3000 };
/* NOTE: for pm8921 and others, voltage of 2500 is 16 (10000b), not 0 */

/* if enable==0, rset and vset are ignored */
static int qcom_coincell_chgr_config(struct qcom_coincell *chgr, int rset,
				     int vset, bool enable)
{
	int i, j, rc;

	/* if disabling, just do that and skip other operations */
	if (!enable)
		return regmap_write(chgr->regmap,
			  chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 0);

	/* find index for current-limiting resistor */
	for (i = 0; i < ARRAY_SIZE(qcom_rset_map); i++)
		if (rset == qcom_rset_map[i])
			break;

	if (i >= ARRAY_SIZE(qcom_rset_map)) {
		dev_err(chgr->dev, "invalid rset-ohms value %d\n", rset);
		return -EINVAL;
	}

	/* find index for charge voltage */
	for (j = 0; j < ARRAY_SIZE(qcom_vset_map); j++)
		if (vset == qcom_vset_map[j])
			break;

	if (j >= ARRAY_SIZE(qcom_vset_map)) {
		dev_err(chgr->dev, "invalid vset-millivolts value %d\n", vset);
		return -EINVAL;
	}

	rc = regmap_write(chgr->regmap,
			  chgr->base_addr + QCOM_COINCELL_REG_RSET, i);
	if (rc) {
		/*
		 * This is mainly to flag a bad base_addr (reg) from dts.
		 * Other failures writing to the registers should be
		 * extremely rare, or indicative of problems that
		 * should be reported elsewhere (eg. spmi failure).
		 */
		dev_err(chgr->dev, "could not write to RSET register\n");
		return rc;
	}

	rc = regmap_write(chgr->regmap,
		chgr->base_addr + QCOM_COINCELL_REG_VSET, j);
	if (rc)
		return rc;

	/* set 'enable' register */
	return regmap_write(chgr->regmap,
			    chgr->base_addr + QCOM_COINCELL_REG_ENABLE,
			    QCOM_COINCELL_ENABLE);
}

static int qcom_coincell_probe(struct platform_device *pdev)
{
	struct device_node *node = pdev->dev.of_node;
	struct qcom_coincell chgr;
	u32 rset = 0;
	u32 vset = 0;
	bool enable;
	int rc;

	chgr.dev = &pdev->dev;

	chgr.regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!chgr.regmap) {
		dev_err(chgr.dev, "Unable to get regmap\n");
		return -EINVAL;
	}

	rc = of_property_read_u32(node, "reg", &chgr.base_addr);
	if (rc)

Annotation

Implementation Notes