drivers/hwmon/emc6w201.c

Source file repositories/reference/linux-study-clean/drivers/hwmon/emc6w201.c

File Facts

System
Linux kernel
Corpus path
drivers/hwmon/emc6w201.c
Extension
.c
Size
14197 bytes
Lines
488
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 emc6w201_data {
	struct i2c_client *client;
	struct mutex update_lock;
	bool valid; /* false until following fields are valid */
	unsigned long last_updated; /* in jiffies */

	/* registers values */
	u8 in[3][6];
	s8 temp[3][6];
	u16 fan[2][5];
};

/*
 * Combine LSB and MSB registers in a single value
 * Locking: must be called with data->update_lock held
 */
static u16 emc6w201_read16(struct i2c_client *client, u8 reg)
{
	int lsb, msb;

	lsb = i2c_smbus_read_byte_data(client, reg);
	msb = i2c_smbus_read_byte_data(client, reg + 1);
	if (unlikely(lsb < 0 || msb < 0)) {
		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
			16, "read", reg);
		return 0xFFFF;	/* Arbitrary value */
	}

	return (msb << 8) | lsb;
}

/*
 * Write 16-bit value to LSB and MSB registers
 * Locking: must be called with data->update_lock held
 */
static int emc6w201_write16(struct i2c_client *client, u8 reg, u16 val)
{
	int err;

	err = i2c_smbus_write_byte_data(client, reg, val & 0xff);
	if (likely(!err))
		err = i2c_smbus_write_byte_data(client, reg + 1, val >> 8);
	if (unlikely(err < 0))
		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
			16, "write", reg);

	return err;
}

/* Read 8-bit value from register */
static u8 emc6w201_read8(struct i2c_client *client, u8 reg)
{
	int val;

	val = i2c_smbus_read_byte_data(client, reg);
	if (unlikely(val < 0)) {
		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
			8, "read", reg);
		return 0x00;	/* Arbitrary value */
	}

	return val;
}

/* Write 8-bit value to register */
static int emc6w201_write8(struct i2c_client *client, u8 reg, u8 val)
{
	int err;

	err = i2c_smbus_write_byte_data(client, reg, val);
	if (unlikely(err < 0))
		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
			8, "write", reg);

	return err;
}

static struct emc6w201_data *emc6w201_update_device(struct device *dev)
{
	struct emc6w201_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int nr;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
		for (nr = 0; nr < 6; nr++) {
			data->in[input][nr] =
				emc6w201_read8(client,
						EMC6W201_REG_IN(nr));

Annotation

Implementation Notes