drivers/hwmon/nct7904.c

Source file repositories/reference/linux-study-clean/drivers/hwmon/nct7904.c

File Facts

System
Linux kernel
Corpus path
drivers/hwmon/nct7904.c
Extension
.c
Size
31379 bytes
Lines
1170
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 nct7904_data {
	struct i2c_client *client;
	struct watchdog_device wdt;
	int bank_sel;
	u32 fanin_mask;
	u32 vsen_mask;
	u32 tcpu_mask;
	u8 fan_mode[FANCTL_MAX];
	u8 enable_dts;
	u8 has_dts;
	u8 temp_mode; /* 0: TR mode, 1: TD mode */
	u8 fan_alarm[2];
	u8 vsen_alarm[3];
};

/* Access functions */
static int nct7904_bank_select(struct nct7904_data *data, unsigned int bank)
{
	int ret;

	if (data->bank_sel == bank)
		return 0;
	ret = i2c_smbus_write_byte_data(data->client, BANK_SEL_REG, bank);
	if (ret < 0) {
		data->bank_sel = -1;
		return ret;
	}
	data->bank_sel = bank;
	return 0;
}

/* Read 1-byte register. Returns unsigned reg or -ERRNO on error. */
static int nct7904_read_reg(struct nct7904_data *data,
			    unsigned int bank, unsigned int reg)
{
	struct i2c_client *client = data->client;
	int ret;

	ret = nct7904_bank_select(data, bank);
	if (ret < 0)
		return ret;
	return i2c_smbus_read_byte_data(client, reg);
}

/*
 * Read 2-byte register. Returns register in big-endian format or
 * -ERRNO on error.
 */
static int nct7904_read_reg16(struct nct7904_data *data,
			      unsigned int bank, unsigned int reg)
{
	struct i2c_client *client = data->client;
	int ret, hi;

	ret = nct7904_bank_select(data, bank);
	if (ret < 0)
		return ret;
	hi = i2c_smbus_read_byte_data(client, reg);
	if (hi < 0)
		return hi;
	ret = i2c_smbus_read_byte_data(client, reg + 1);
	if (ret < 0)
		return ret;
	return ret | (hi << 8);
}

/* Write 1-byte register. Returns 0 or -ERRNO on error. */
static int nct7904_write_reg(struct nct7904_data *data,
			     unsigned int bank, unsigned int reg, u8 val)
{
	struct i2c_client *client = data->client;
	int ret;

	ret = nct7904_bank_select(data, bank);
	if (ret < 0)
		return ret;
	return i2c_smbus_write_byte_data(client, reg, val);
}

static int nct7904_read_fan(struct device *dev, u32 attr, int channel,
			    long *val)
{
	struct nct7904_data *data = dev_get_drvdata(dev);
	unsigned int cnt, rpm;
	int ret;

	switch (attr) {
	case hwmon_fan_input:
		ret = nct7904_read_reg16(data, BANK_0,
					 FANIN1_HV_REG + channel * 2);

Annotation

Implementation Notes