drivers/hwmon/pmbus/mp2925.c

Source file repositories/reference/linux-study-clean/drivers/hwmon/pmbus/mp2925.c

File Facts

System
Linux kernel
Corpus path
drivers/hwmon/pmbus/mp2925.c
Extension
.c
Size
8935 bytes
Lines
336
Domain
Driver Families
Bucket
drivers/hwmon
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 mp2925_data {
	struct pmbus_driver_info info;
	int vout_scale[MP2925_PAGE_NUM];
	int vid_offset[MP2925_PAGE_NUM];
};

#define to_mp2925_data(x) container_of(x, struct mp2925_data, info)

static u16 mp2925_linear_exp_transfer(u16 word, u16 expect_exponent)
{
	s16 exponent, mantissa, target_exponent;

	exponent = ((s16)word) >> 11;
	mantissa = ((s16)((word & 0x7ff) << 5)) >> 5;
	target_exponent = (s16)((expect_exponent & 0x1f) << 11) >> 11;

	if (exponent > target_exponent)
		mantissa = mantissa << (exponent - target_exponent);
	else
		mantissa = mantissa >> (target_exponent - exponent);

	return (mantissa & 0x7ff) | ((expect_exponent << 11) & 0xf800);
}

static int mp2925_read_byte_data(struct i2c_client *client, int page, int reg)
{
	int ret;

	switch (reg) {
	case PMBUS_VOUT_MODE:
		/*
		 * The MP2925 does not follow standard PMBus protocol completely,
		 * and the calculation of vout in this driver is based on direct
		 * format. As a result, the format of vout is enforced to direct.
		 */
		ret = PB_VOUT_MODE_DIRECT;
		break;
	default:
		ret = -ENODATA;
		break;
	}

	return ret;
}

static int mp2925_read_word_data(struct i2c_client *client, int page, int phase,
				 int reg)
{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct mp2925_data *data = to_mp2925_data(info);
	int ret;

	switch (reg) {
	case PMBUS_READ_VOUT:
		ret = pmbus_read_word_data(client, page, phase, reg);
		if (ret < 0)
			return ret;

		/*
		 * In vid mode, the MP2925 vout telemetry has 49 vid step offset, but
		 * PMBUS_VOUT_OV_FAULT_LIMIT and PMBUS_VOUT_UV_FAULT_LIMIT do not take
		 * this into consideration, its resolution is 1.95mV/LSB, as a result,
		 * format[PSC_VOLTAGE_OUT] can not be set to vid directly. Adding extra
		 * vid_offset variable for vout telemetry.
		 */
		ret = DIV_ROUND_CLOSEST(((ret & GENMASK(11, 0)) + data->vid_offset[page]) *
					data->vout_scale[page], MP2925_VOUT_DIV);
		break;
	case PMBUS_VOUT_OV_FAULT_LIMIT:
	case PMBUS_VOUT_UV_FAULT_LIMIT:
		ret = pmbus_read_word_data(client, page, phase, reg);
		if (ret < 0)
			return ret;

		ret = DIV_ROUND_CLOSEST((ret & GENMASK(11, 0)) * MP2925_VOUT_OVUV_UINT,
					MP2925_VOUT_OVUV_DIV);
		break;
	case PMBUS_STATUS_WORD:
	case PMBUS_READ_VIN:
	case PMBUS_READ_IOUT:
	case PMBUS_READ_POUT:
	case PMBUS_READ_PIN:
	case PMBUS_READ_IIN:
	case PMBUS_READ_TEMPERATURE_1:
	case PMBUS_VIN_OV_FAULT_LIMIT:
	case PMBUS_VIN_OV_WARN_LIMIT:
	case PMBUS_VIN_UV_WARN_LIMIT:
	case PMBUS_VIN_UV_FAULT_LIMIT:
	case PMBUS_IOUT_OC_FAULT_LIMIT:
	case PMBUS_IOUT_OC_WARN_LIMIT:

Annotation

Implementation Notes