drivers/macintosh/windfarm_lm75_sensor.c

Source file repositories/reference/linux-study-clean/drivers/macintosh/windfarm_lm75_sensor.c

File Facts

System
Linux kernel
Corpus path
drivers/macintosh/windfarm_lm75_sensor.c
Extension
.c
Size
4357 bytes
Lines
191
Domain
Driver Families
Bucket
drivers/macintosh
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 wf_lm75_sensor {
	unsigned int		ds1775 : 1;
	unsigned int		inited : 1;
	struct i2c_client	*i2c;
	struct wf_sensor	sens;
};
#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)

static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
{
	struct wf_lm75_sensor *lm = wf_to_lm75(sr);
	s32 data;

	if (lm->i2c == NULL)
		return -ENODEV;

	/* Init chip if necessary */
	if (!lm->inited) {
		u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);

		DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
		    sr->name, cfg);

		/* clear shutdown bit, keep other settings as left by
		 * the firmware for now
		 */
		cfg_new = cfg & ~0x01;
		i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
		lm->inited = 1;

		/* If we just powered it up, let's wait 200 ms */
		msleep(200);
	}

	/* Read temperature register */
	data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
	data <<= 8;
	*value = data;

	return 0;
}

static void wf_lm75_release(struct wf_sensor *sr)
{
	struct wf_lm75_sensor *lm = wf_to_lm75(sr);

	kfree(lm);
}

static const struct wf_sensor_ops wf_lm75_ops = {
	.get_value	= wf_lm75_get,
	.release	= wf_lm75_release,
	.owner		= THIS_MODULE,
};

static int wf_lm75_probe(struct i2c_client *client)
{
	const struct i2c_device_id *id = i2c_client_get_device_id(client);
	struct wf_lm75_sensor *lm;
	int rc, ds1775;
	const char *name, *loc;

	if (id)
		ds1775 = id->driver_data;
	else
		ds1775 = !!of_device_get_match_data(&client->dev);

	DBG("wf_lm75: creating  %s device at address 0x%02x\n",
	    ds1775 ? "ds1775" : "lm75", client->addr);

	loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
	if (!loc) {
		dev_warn(&client->dev, "Missing hwsensor-location property!\n");
		return -ENXIO;
	}

	/* Usual rant about sensor names not beeing very consistent in
	 * the device-tree, oh well ...
	 * Add more entries below as you deal with more setups
	 */
	if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
		name = "hd-temp";
	else if (!strcmp(loc, "Incoming Air Temp"))
		name = "incoming-air-temp";
	else if (!strcmp(loc, "ODD Temp"))
		name = "optical-drive-temp";
	else if (!strcmp(loc, "HD Temp"))
		name = "hard-drive-temp";
	else if (!strcmp(loc, "PCI SLOTS"))
		name = "slots-temp";

Annotation

Implementation Notes