drivers/hwmon/sht15.c

Source file repositories/reference/linux-study-clean/drivers/hwmon/sht15.c

File Facts

System
Linux kernel
Corpus path
drivers/hwmon/sht15.c
Extension
.c
Size
27879 bytes
Lines
1061
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 sht15_temppair {
	int vdd; /* microvolts */
	int d1;
};

/* Table 9 from datasheet - relates temperature calculation to supply voltage */
static const struct sht15_temppair temppoints[] = {
	{ 2500000, -39400 },
	{ 3000000, -39600 },
	{ 3500000, -39700 },
	{ 4000000, -39800 },
	{ 5000000, -40100 },
};

/* Table from CRC datasheet, section 2.4 */
static const u8 sht15_crc8_table[] = {
	0,	49,	98,	83,	196,	245,	166,	151,
	185,	136,	219,	234,	125,	76,	31,	46,
	67,	114,	33,	16,	135,	182,	229,	212,
	250,	203,	152,	169,	62,	15,	92,	109,
	134,	183,	228,	213,	66,	115,	32,	17,
	63,	14,	93,	108,	251,	202,	153,	168,
	197,	244,	167,	150,	1,	48,	99,	82,
	124,	77,	30,	47,	184,	137,	218,	235,
	61,	12,	95,	110,	249,	200,	155,	170,
	132,	181,	230,	215,	64,	113,	34,	19,
	126,	79,	28,	45,	186,	139,	216,	233,
	199,	246,	165,	148,	3,	50,	97,	80,
	187,	138,	217,	232,	127,	78,	29,	44,
	2,	51,	96,	81,	198,	247,	164,	149,
	248,	201,	154,	171,	60,	13,	94,	111,
	65,	112,	35,	18,	133,	180,	231,	214,
	122,	75,	24,	41,	190,	143,	220,	237,
	195,	242,	161,	144,	7,	54,	101,	84,
	57,	8,	91,	106,	253,	204,	159,	174,
	128,	177,	226,	211,	68,	117,	38,	23,
	252,	205,	158,	175,	56,	9,	90,	107,
	69,	116,	39,	22,	129,	176,	227,	210,
	191,	142,	221,	236,	123,	74,	25,	40,
	6,	55,	100,	85,	194,	243,	160,	145,
	71,	118,	37,	20,	131,	178,	225,	208,
	254,	207,	156,	173,	58,	11,	88,	105,
	4,	53,	102,	87,	192,	241,	162,	147,
	189,	140,	223,	238,	121,	72,	27,	42,
	193,	240,	163,	146,	5,	52,	103,	86,
	120,	73,	26,	43,	188,	141,	222,	239,
	130,	179,	224,	209,	70,	119,	36,	21,
	59,	10,	89,	104,	255,	206,	157,	172
};

/**
 * struct sht15_data - device instance specific data
 * @sck:		clock GPIO line
 * @data:		data GPIO line
 * @read_work:		bh of interrupt handler.
 * @wait_queue:		wait queue for getting values from device.
 * @val_temp:		last temperature value read from device.
 * @val_humid:		last humidity value read from device.
 * @val_status:		last status register value read from device.
 * @checksum_ok:	last value read from the device passed CRC validation.
 * @checksumming:	flag used to enable the data validation with CRC.
 * @state:		state identifying the action the driver is doing.
 * @measurements_valid:	are the current stored measures valid (start condition).
 * @status_valid:	is the current stored status valid (start condition).
 * @last_measurement:	time of last measure.
 * @last_status:	time of last status reading.
 * @read_lock:		mutex to ensure only one read in progress at a time.
 * @dev:		associate device structure.
 * @hwmon_dev:		device associated with hwmon subsystem.
 * @reg:		associated regulator (if specified).
 * @nb:			notifier block to handle notifications of voltage
 *                      changes.
 * @supply_uv:		local copy of supply voltage used to allow use of
 *                      regulator consumer if available.
 * @supply_uv_valid:	indicates that an updated value has not yet been
 *			obtained from the regulator and so any calculations
 *			based upon it will be invalid.
 * @update_supply_work:	work struct that is used to update the supply_uv.
 * @interrupt_handled:	flag used to indicate a handler has been scheduled.
 */
struct sht15_data {
	struct gpio_desc		*sck;
	struct gpio_desc		*data;
	struct work_struct		read_work;
	wait_queue_head_t		wait_queue;
	uint16_t			val_temp;
	uint16_t			val_humid;
	u8				val_status;
	bool				checksum_ok;
	bool				checksumming;

Annotation

Implementation Notes