twl4030_madc_battery.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Dumb driver for LiIon batteries using TWL4030 madc.
  4 *
  5 * Copyright 2013 Golden Delicious Computers
  6 * Lukas Märdian <lukas@goldelico.com>
  7 *
  8 * Based on dumb driver for gta01 battery
  9 * Copyright 2009 Openmoko, Inc
 10 * Balaji Rao <balajirrao@openmoko.org>
 11 */
 12
 13#include <linux/module.h>
 14#include <linux/param.h>
 15#include <linux/delay.h>
 16#include <linux/workqueue.h>
 17#include <linux/platform_device.h>
 18#include <linux/power_supply.h>
 19#include <linux/slab.h>
 20#include <linux/sort.h>
 21#include <linux/power/twl4030_madc_battery.h>
 22#include <linux/iio/consumer.h>
 23
 24struct twl4030_madc_battery {
 25	struct power_supply *psy;
 26	struct twl4030_madc_bat_platform_data *pdata;
 27	struct iio_channel *channel_temp;
 28	struct iio_channel *channel_ichg;
 29	struct iio_channel *channel_vbat;
 30};
 31
 32static enum power_supply_property twl4030_madc_bat_props[] = {
 33	POWER_SUPPLY_PROP_PRESENT,
 34	POWER_SUPPLY_PROP_STATUS,
 35	POWER_SUPPLY_PROP_TECHNOLOGY,
 36	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 37	POWER_SUPPLY_PROP_CURRENT_NOW,
 38	POWER_SUPPLY_PROP_CAPACITY,
 39	POWER_SUPPLY_PROP_CHARGE_FULL,
 40	POWER_SUPPLY_PROP_CHARGE_NOW,
 41	POWER_SUPPLY_PROP_TEMP,
 42	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 43};
 44
 45static int madc_read(struct iio_channel *channel)
 46{
 47	int val, err;
 48	err = iio_read_channel_processed(channel, &val);
 49	if (err < 0)
 50		return err;
 51
 52	return val;
 53}
 54
 55static int twl4030_madc_bat_get_charging_status(struct twl4030_madc_battery *bt)
 56{
 57	return (madc_read(bt->channel_ichg) > 0) ? 1 : 0;
 58}
 59
 60static int twl4030_madc_bat_get_voltage(struct twl4030_madc_battery *bt)
 61{
 62	return madc_read(bt->channel_vbat);
 63}
 64
 65static int twl4030_madc_bat_get_current(struct twl4030_madc_battery *bt)
 66{
 67	return madc_read(bt->channel_ichg) * 1000;
 68}
 69
 70static int twl4030_madc_bat_get_temp(struct twl4030_madc_battery *bt)
 71{
 72	return madc_read(bt->channel_temp) * 10;
 73}
 74
 75static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
 76					int volt)
 77{
 78	struct twl4030_madc_bat_calibration *calibration;
 79	int i, res = 0;
 80
 81	/* choose charging curve */
 82	if (twl4030_madc_bat_get_charging_status(bat))
 83		calibration = bat->pdata->charging;
 84	else
 85		calibration = bat->pdata->discharging;
 86
 87	if (volt > calibration[0].voltage) {
 88		res = calibration[0].level;
 89	} else {
 90		for (i = 0; calibration[i+1].voltage >= 0; i++) {
 91			if (volt <= calibration[i].voltage &&
 92					volt >= calibration[i+1].voltage) {
 93				/* interval found - interpolate within range */
 94				res = calibration[i].level -
 95					((calibration[i].voltage - volt) *
 96					(calibration[i].level -
 97					calibration[i+1].level)) /
 98					(calibration[i].voltage -
 99					calibration[i+1].voltage);
100				break;
101			}
102		}
103	}
104	return res;
105}
106
107static int twl4030_madc_bat_get_property(struct power_supply *psy,
108					enum power_supply_property psp,
109					union power_supply_propval *val)
110{
111	struct twl4030_madc_battery *bat = power_supply_get_drvdata(psy);
112
113	switch (psp) {
114	case POWER_SUPPLY_PROP_STATUS:
115		if (twl4030_madc_bat_voltscale(bat,
116				twl4030_madc_bat_get_voltage(bat)) > 95)
117			val->intval = POWER_SUPPLY_STATUS_FULL;
118		else {
119			if (twl4030_madc_bat_get_charging_status(bat))
120				val->intval = POWER_SUPPLY_STATUS_CHARGING;
121			else
122				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
123		}
124		break;
125	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
126		val->intval = twl4030_madc_bat_get_voltage(bat) * 1000;
127		break;
128	case POWER_SUPPLY_PROP_TECHNOLOGY:
129		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
130		break;
131	case POWER_SUPPLY_PROP_CURRENT_NOW:
132		val->intval = twl4030_madc_bat_get_current(bat);
133		break;
134	case POWER_SUPPLY_PROP_PRESENT:
135		/* assume battery is always present */
136		val->intval = 1;
137		break;
138	case POWER_SUPPLY_PROP_CHARGE_NOW: {
139			int percent = twl4030_madc_bat_voltscale(bat,
140					twl4030_madc_bat_get_voltage(bat));
141			val->intval = (percent * bat->pdata->capacity) / 100;
142			break;
143		}
144	case POWER_SUPPLY_PROP_CAPACITY:
145		val->intval = twl4030_madc_bat_voltscale(bat,
146					twl4030_madc_bat_get_voltage(bat));
147		break;
148	case POWER_SUPPLY_PROP_CHARGE_FULL:
149		val->intval = bat->pdata->capacity;
150		break;
151	case POWER_SUPPLY_PROP_TEMP:
152		val->intval = twl4030_madc_bat_get_temp(bat);
153		break;
154	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
155			int percent = twl4030_madc_bat_voltscale(bat,
156					twl4030_madc_bat_get_voltage(bat));
157			/* in mAh */
158			int chg = (percent * (bat->pdata->capacity/1000))/100;
159
160			/* assume discharge with 400 mA (ca. 1.5W) */
161			val->intval = (3600l * chg) / 400;
162			break;
163		}
164	default:
165		return -EINVAL;
166	}
167
168	return 0;
169}
170
171static const struct power_supply_desc twl4030_madc_bat_desc = {
172	.name			= "twl4030_battery",
173	.type			= POWER_SUPPLY_TYPE_BATTERY,
174	.properties		= twl4030_madc_bat_props,
175	.num_properties		= ARRAY_SIZE(twl4030_madc_bat_props),
176	.get_property		= twl4030_madc_bat_get_property,
177	.external_power_changed	= power_supply_changed,
178};
179
180static int twl4030_cmp(const void *a, const void *b)
181{
182	return ((struct twl4030_madc_bat_calibration *)b)->voltage -
183		((struct twl4030_madc_bat_calibration *)a)->voltage;
184}
185
186static int twl4030_madc_battery_probe(struct platform_device *pdev)
187{
188	struct twl4030_madc_battery *twl4030_madc_bat;
189	struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
190	struct power_supply_config psy_cfg = {};
191
192	twl4030_madc_bat = devm_kzalloc(&pdev->dev, sizeof(*twl4030_madc_bat),
193				GFP_KERNEL);
194	if (!twl4030_madc_bat)
195		return -ENOMEM;
196
197	twl4030_madc_bat->channel_temp = devm_iio_channel_get(&pdev->dev, "temp");
198	if (IS_ERR(twl4030_madc_bat->channel_temp))
199		return PTR_ERR(twl4030_madc_bat->channel_temp);
200
201	twl4030_madc_bat->channel_ichg = devm_iio_channel_get(&pdev->dev, "ichg");
202	if (IS_ERR(twl4030_madc_bat->channel_ichg))
203		return PTR_ERR(twl4030_madc_bat->channel_ichg);
204
205	twl4030_madc_bat->channel_vbat = devm_iio_channel_get(&pdev->dev, "vbat");
206	if (IS_ERR(twl4030_madc_bat->channel_vbat))
207		return PTR_ERR(twl4030_madc_bat->channel_vbat);
208
209	/* sort charging and discharging calibration data */
210	sort(pdata->charging, pdata->charging_size,
211		sizeof(struct twl4030_madc_bat_calibration),
212		twl4030_cmp, NULL);
213	sort(pdata->discharging, pdata->discharging_size,
214		sizeof(struct twl4030_madc_bat_calibration),
215		twl4030_cmp, NULL);
216
217	twl4030_madc_bat->pdata = pdata;
218	psy_cfg.drv_data = twl4030_madc_bat;
219	twl4030_madc_bat->psy = devm_power_supply_register(&pdev->dev,
220							   &twl4030_madc_bat_desc,
221							   &psy_cfg);
222	if (IS_ERR(twl4030_madc_bat->psy))
223		return PTR_ERR(twl4030_madc_bat->psy);
224
225	return 0;
226}
227
228static struct platform_driver twl4030_madc_battery_driver = {
229	.driver = {
230		.name = "twl4030_madc_battery",
231	},
232	.probe  = twl4030_madc_battery_probe,
233};
234module_platform_driver(twl4030_madc_battery_driver);
235
236MODULE_LICENSE("GPL");
237MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
238MODULE_DESCRIPTION("twl4030_madc battery driver");
239MODULE_ALIAS("platform:twl4030_madc_battery");