linux/drivers/power/supply/rx51_battery.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Nokia RX-51 battery driver
 *
 * Copyright (C) 2012  Pali Rohár <[email protected]>
 */

#include <linux/module.h>
#include <linux/param.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/iio/consumer.h>
#include <linux/of.h>

struct rx51_device_info { … };

/*
 * Read ADCIN channel value, code copied from maemo kernel
 */
static int rx51_battery_read_adc(struct iio_channel *channel)
{ … }

/*
 * 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)
{ … }

/*
 * 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[] = …;

/*
 * 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 …
static u16 rx51_temp_table2[] = …;

/*
 * 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)
{ … }

/*
 * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah
 * This conversion formula was extracted from maemo program bsi-read
 */
static int rx51_battery_read_capacity(struct rx51_device_info *di)
{ … }

/*
 * Return power_supply property
 */
static int rx51_battery_get_property(struct power_supply *psy,
					enum power_supply_property psp,
					union power_supply_propval *val)
{ … }

static enum power_supply_property rx51_battery_props[] = …;

static int rx51_battery_probe(struct platform_device *pdev)
{ … }

#ifdef CONFIG_OF
static const struct of_device_id n900_battery_of_match[] = …;
MODULE_DEVICE_TABLE(of, n900_battery_of_match);
#endif

static struct platform_driver rx51_battery_driver = …;
module_platform_driver(…) …;

MODULE_ALIAS(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;