1/*
2 * Dumb driver for LiIon batteries using TWL4030 madc.
3 *
4 * Copyright 2013 Golden Delicious Computers
5 * Lukas Märdian <lukas@goldelico.com>
6 *
7 * Based on dumb driver for gta01 battery
8 * Copyright 2009 Openmoko, Inc
9 * Balaji Rao <balajirrao@openmoko.org>
10 */
11
12#include <linux/module.h>
13#include <linux/param.h>
14#include <linux/delay.h>
15#include <linux/workqueue.h>
16#include <linux/platform_device.h>
17#include <linux/power_supply.h>
18#include <linux/slab.h>
19#include <linux/sort.h>
20#include <linux/i2c/twl4030-madc.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 void twl4030_madc_bat_ext_changed(struct power_supply *psy)
172{
173	power_supply_changed(psy);
174}
175
176static const struct power_supply_desc twl4030_madc_bat_desc = {
177	.name			= "twl4030_battery",
178	.type			= POWER_SUPPLY_TYPE_BATTERY,
179	.properties		= twl4030_madc_bat_props,
180	.num_properties		= ARRAY_SIZE(twl4030_madc_bat_props),
181	.get_property		= twl4030_madc_bat_get_property,
182	.external_power_changed	= twl4030_madc_bat_ext_changed,
183
184};
185
186static int twl4030_cmp(const void *a, const void *b)
187{
188	return ((struct twl4030_madc_bat_calibration *)b)->voltage -
189		((struct twl4030_madc_bat_calibration *)a)->voltage;
190}
191
192static int twl4030_madc_battery_probe(struct platform_device *pdev)
193{
194	struct twl4030_madc_battery *twl4030_madc_bat;
195	struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
196	struct power_supply_config psy_cfg = {};
197	int ret = 0;
198
199	twl4030_madc_bat = devm_kzalloc(&pdev->dev, sizeof(*twl4030_madc_bat),
200				GFP_KERNEL);
201	if (!twl4030_madc_bat)
202		return -ENOMEM;
203
204	twl4030_madc_bat->channel_temp = iio_channel_get(&pdev->dev, "temp");
205	if (IS_ERR(twl4030_madc_bat->channel_temp)) {
206		ret = PTR_ERR(twl4030_madc_bat->channel_temp);
207		goto err;
208	}
209
210	twl4030_madc_bat->channel_ichg = iio_channel_get(&pdev->dev, "ichg");
211	if (IS_ERR(twl4030_madc_bat->channel_ichg)) {
212		ret = PTR_ERR(twl4030_madc_bat->channel_ichg);
213		goto err_temp;
214	}
215
216	twl4030_madc_bat->channel_vbat = iio_channel_get(&pdev->dev, "vbat");
217	if (IS_ERR(twl4030_madc_bat->channel_vbat)) {
218		ret = PTR_ERR(twl4030_madc_bat->channel_vbat);
219		goto err_ichg;
220	}
221
222	/* sort charging and discharging calibration data */
223	sort(pdata->charging, pdata->charging_size,
224		sizeof(struct twl4030_madc_bat_calibration),
225		twl4030_cmp, NULL);
226	sort(pdata->discharging, pdata->discharging_size,
227		sizeof(struct twl4030_madc_bat_calibration),
228		twl4030_cmp, NULL);
229
230	twl4030_madc_bat->pdata = pdata;
231	platform_set_drvdata(pdev, twl4030_madc_bat);
232	psy_cfg.drv_data = twl4030_madc_bat;
233	twl4030_madc_bat->psy = power_supply_register(&pdev->dev,
234						      &twl4030_madc_bat_desc,
235						      &psy_cfg);
236	if (IS_ERR(twl4030_madc_bat->psy)) {
237		ret = PTR_ERR(twl4030_madc_bat->psy);
238		goto err_vbat;
239	}
240
241	return 0;
242
243err_vbat:
244	iio_channel_release(twl4030_madc_bat->channel_vbat);
245err_ichg:
246	iio_channel_release(twl4030_madc_bat->channel_ichg);
247err_temp:
248	iio_channel_release(twl4030_madc_bat->channel_temp);
249err:
250	return ret;
251}
252
253static int twl4030_madc_battery_remove(struct platform_device *pdev)
254{
255	struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
256
257	power_supply_unregister(bat->psy);
258
259	iio_channel_release(bat->channel_vbat);
260	iio_channel_release(bat->channel_ichg);
261	iio_channel_release(bat->channel_temp);
262
263	return 0;
264}
265
266static struct platform_driver twl4030_madc_battery_driver = {
267	.driver = {
268		.name = "twl4030_madc_battery",
269	},
270	.probe  = twl4030_madc_battery_probe,
271	.remove = twl4030_madc_battery_remove,
272};
273module_platform_driver(twl4030_madc_battery_driver);
274
275MODULE_LICENSE("GPL");
276MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
277MODULE_DESCRIPTION("twl4030_madc battery driver");
278MODULE_ALIAS("platform:twl4030_madc_battery");
279