drivers/hwmon/pmbus/ltc2978.c

Source file repositories/reference/linux-study-clean/drivers/hwmon/pmbus/ltc2978.c

File Facts

System
Linux kernel
Corpus path
drivers/hwmon/pmbus/ltc2978.c
Extension
.c
Size
29209 bytes
Lines
1015
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 ltc2978_data {
	enum chips id;
	u16 vin_min, vin_max;
	u16 temp_min[LTC2974_NUM_PAGES], temp_max[LTC2974_NUM_PAGES];
	u16 vout_min[LTC2978_NUM_PAGES], vout_max[LTC2978_NUM_PAGES];
	u16 iout_min[LTC2974_NUM_PAGES], iout_max[LTC2974_NUM_PAGES];
	u16 iin_min, iin_max;
	u16 pin_min, pin_max;
	u16 temp2_max;
	struct pmbus_driver_info info;
	u32 features;
};
#define to_ltc2978_data(x)  container_of(x, struct ltc2978_data, info)

#define FEAT_CLEAR_PEAKS	BIT(0)
#define FEAT_NEEDS_POLLING	BIT(1)

#define has_clear_peaks(d)	((d)->features & FEAT_CLEAR_PEAKS)
#define needs_polling(d)	((d)->features & FEAT_NEEDS_POLLING)

static int ltc_wait_ready(struct i2c_client *client)
{
	unsigned long timeout = jiffies + msecs_to_jiffies(LTC_POLL_TIMEOUT);
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct ltc2978_data *data = to_ltc2978_data(info);
	int status;
	u8 mask;

	if (!needs_polling(data))
		return 0;

	/*
	 * LTC3883 does not support LTC_NOT_PENDING, even though
	 * the datasheet claims that it does.
	 */
	mask = LTC_NOT_BUSY;
	if (data->id != ltc3883)
		mask |= LTC_NOT_PENDING;

	do {
		status = pmbus_read_byte_data(client, 0, LTC2978_MFR_COMMON);
		if (status == -EBADMSG || status == -ENXIO) {
			/* PEC error or NACK: chip may be busy, try again */
			usleep_range(50, 100);
			continue;
		}
		if (status < 0)
			return status;

		if ((status & mask) == mask)
			return 0;

		usleep_range(50, 100);
	} while (time_before(jiffies, timeout));

	return -ETIMEDOUT;
}

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

	ret = ltc_wait_ready(client);
	if (ret < 0)
		return ret;

	return pmbus_read_word_data(client, page, 0xff, reg);
}

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

	ret = ltc_wait_ready(client);
	if (ret < 0)
		return ret;

	return pmbus_read_byte_data(client, page, reg);
}

static int ltc_write_byte_data(struct i2c_client *client, int page, int reg, u8 value)
{
	int ret;

	ret = ltc_wait_ready(client);
	if (ret < 0)
		return ret;

	return pmbus_write_byte_data(client, page, reg, value);

Annotation

Implementation Notes