drivers/power/supply/rx51_battery.c

Source file repositories/reference/linux-study-clean/drivers/power/supply/rx51_battery.c

File Facts

System
Linux kernel
Corpus path
drivers/power/supply/rx51_battery.c
Extension
.c
Size
6719 bytes
Lines
249
Domain
Driver Families
Bucket
drivers/power
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 rx51_device_info {
	struct device *dev;
	struct power_supply *bat;
	struct power_supply_desc bat_desc;
	struct iio_channel *channel_temp;
	struct iio_channel *channel_bsi;
	struct iio_channel *channel_vbat;
};

/*
 * Read ADCIN channel value, code copied from maemo kernel
 */
static int rx51_battery_read_adc(struct iio_channel *channel)
{
	int val, err;
	err = iio_read_channel_average_raw(channel, &val);
	if (err < 0)
		return err;
	return val;
}

/*
 * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage
 * This conversion formula was extracted from maemo program bsi-read
 */
static int rx51_battery_read_voltage(struct rx51_device_info *di)
{
	int voltage = rx51_battery_read_adc(di->channel_vbat);

	if (voltage < 0) {
		dev_err(di->dev, "Could not read ADC: %d\n", voltage);
		return voltage;
	}

	return 1000 * (10000 * voltage / 1705);
}

/*
 * Temperature look-up tables
 * TEMP = (1/(t1 + 1/298) - 273.15)
 * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255))
 * Formula is based on experimental data, RX-51 CAL data, maemo program bme
 * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671
 */

/*
 * Table1 (temperature for first 25 RAW values)
 * Usage: TEMP = rx51_temp_table1[RAW]
 *   RAW is between 1 and 24
 *   TEMP is between 201 C and 55 C
 */
static u8 rx51_temp_table1[] = {
	255, 201, 159, 138, 124, 114, 106,  99,  94,  89,  85,  82,  78,  75,
	 73,  70,  68,  66,  64,  62,  61,  59,  57,  56,  55
};

/*
 * Table2 (lowest RAW value for temperature)
 * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first]
 *   TEMP is between 53 C and -32 C
 *   RAW is between 25 and 993
 */
#define rx51_temp_table2_first 53
static u16 rx51_temp_table2[] = {
	 25,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  39,
	 40,  41,  43,  44,  46,  48,  49,  51,  53,  55,  57,  59,  61,  64,
	 66,  69,  71,  74,  77,  80,  83,  86,  90,  94,  97, 101, 106, 110,
	115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211,
	221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415,
	437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885,
	937, 993, 1024
};

/*
 * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius
 * Use Temperature look-up tables for conversation
 */
static int rx51_battery_read_temperature(struct rx51_device_info *di)
{
	int min = 0;
	int max = ARRAY_SIZE(rx51_temp_table2) - 1;
	int raw = rx51_battery_read_adc(di->channel_temp);

	if (raw < 0)
		dev_err(di->dev, "Could not read ADC: %d\n", raw);

	/* Zero and negative values are undefined */
	if (raw <= 0)
		return INT_MAX;

Annotation

Implementation Notes