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
23struct twl4030_madc_battery {
24	struct power_supply psy;
25	struct twl4030_madc_bat_platform_data *pdata;
26};
27
28static enum power_supply_property twl4030_madc_bat_props[] = {
29	POWER_SUPPLY_PROP_PRESENT,
30	POWER_SUPPLY_PROP_STATUS,
31	POWER_SUPPLY_PROP_TECHNOLOGY,
32	POWER_SUPPLY_PROP_VOLTAGE_NOW,
33	POWER_SUPPLY_PROP_CURRENT_NOW,
34	POWER_SUPPLY_PROP_CAPACITY,
35	POWER_SUPPLY_PROP_CHARGE_FULL,
36	POWER_SUPPLY_PROP_CHARGE_NOW,
37	POWER_SUPPLY_PROP_TEMP,
38	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
39};
40
41static int madc_read(int index)
42{
43	struct twl4030_madc_request req;
44	int val;
45
46	req.channels = index;
47	req.method = TWL4030_MADC_SW2;
48	req.type = TWL4030_MADC_WAIT;
49	req.do_avg = 0;
50	req.raw = false;
51	req.func_cb = NULL;
52
53	val = twl4030_madc_conversion(&req);
54	if (val < 0)
55		return val;
56
57	return req.rbuf[ffs(index) - 1];
58}
59
60static int twl4030_madc_bat_get_charging_status(void)
61{
62	return (madc_read(TWL4030_MADC_ICHG) > 0) ? 1 : 0;
63}
64
65static int twl4030_madc_bat_get_voltage(void)
66{
67	return madc_read(TWL4030_MADC_VBAT);
68}
69
70static int twl4030_madc_bat_get_current(void)
71{
72	return madc_read(TWL4030_MADC_ICHG) * 1000;
73}
74
75static int twl4030_madc_bat_get_temp(void)
76{
77	return madc_read(TWL4030_MADC_BTEMP) * 10;
78}
79
80static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
81					int volt)
82{
83	struct twl4030_madc_bat_calibration *calibration;
84	int i, res = 0;
85
86	/* choose charging curve */
87	if (twl4030_madc_bat_get_charging_status())
88		calibration = bat->pdata->charging;
89	else
90		calibration = bat->pdata->discharging;
91
92	if (volt > calibration[0].voltage) {
93		res = calibration[0].level;
94	} else {
95		for (i = 0; calibration[i+1].voltage >= 0; i++) {
96			if (volt <= calibration[i].voltage &&
97					volt >= calibration[i+1].voltage) {
98				/* interval found - interpolate within range */
99				res = calibration[i].level -
100					((calibration[i].voltage - volt) *
101					(calibration[i].level -
102					calibration[i+1].level)) /
103					(calibration[i].voltage -
104					calibration[i+1].voltage);
105				break;
106			}
107		}
108	}
109	return res;
110}
111
112static int twl4030_madc_bat_get_property(struct power_supply *psy,
113					enum power_supply_property psp,
114					union power_supply_propval *val)
115{
116	struct twl4030_madc_battery *bat = container_of(psy,
117					struct twl4030_madc_battery, psy);
118
119	switch (psp) {
120	case POWER_SUPPLY_PROP_STATUS:
121		if (twl4030_madc_bat_voltscale(bat,
122				twl4030_madc_bat_get_voltage()) > 95)
123			val->intval = POWER_SUPPLY_STATUS_FULL;
124		else {
125			if (twl4030_madc_bat_get_charging_status())
126				val->intval = POWER_SUPPLY_STATUS_CHARGING;
127			else
128				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
129		}
130		break;
131	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
132		val->intval = twl4030_madc_bat_get_voltage() * 1000;
133		break;
134	case POWER_SUPPLY_PROP_TECHNOLOGY:
135		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
136		break;
137	case POWER_SUPPLY_PROP_CURRENT_NOW:
138		val->intval = twl4030_madc_bat_get_current();
139		break;
140	case POWER_SUPPLY_PROP_PRESENT:
141		/* assume battery is always present */
142		val->intval = 1;
143		break;
144	case POWER_SUPPLY_PROP_CHARGE_NOW: {
145			int percent = twl4030_madc_bat_voltscale(bat,
146					twl4030_madc_bat_get_voltage());
147			val->intval = (percent * bat->pdata->capacity) / 100;
148			break;
149		}
150	case POWER_SUPPLY_PROP_CAPACITY:
151		val->intval = twl4030_madc_bat_voltscale(bat,
152					twl4030_madc_bat_get_voltage());
153		break;
154	case POWER_SUPPLY_PROP_CHARGE_FULL:
155		val->intval = bat->pdata->capacity;
156		break;
157	case POWER_SUPPLY_PROP_TEMP:
158		val->intval = twl4030_madc_bat_get_temp();
159		break;
160	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
161			int percent = twl4030_madc_bat_voltscale(bat,
162					twl4030_madc_bat_get_voltage());
163			/* in mAh */
164			int chg = (percent * (bat->pdata->capacity/1000))/100;
165
166			/* assume discharge with 400 mA (ca. 1.5W) */
167			val->intval = (3600l * chg) / 400;
168			break;
169		}
170	default:
171		return -EINVAL;
172	}
173
174	return 0;
175}
176
177static void twl4030_madc_bat_ext_changed(struct power_supply *psy)
178{
179	struct twl4030_madc_battery *bat = container_of(psy,
180					struct twl4030_madc_battery, psy);
181
182	power_supply_changed(&bat->psy);
183}
184
185static int twl4030_cmp(const void *a, const void *b)
186{
187	return ((struct twl4030_madc_bat_calibration *)b)->voltage -
188		((struct twl4030_madc_bat_calibration *)a)->voltage;
189}
190
191static int twl4030_madc_battery_probe(struct platform_device *pdev)
192{
193	struct twl4030_madc_battery *twl4030_madc_bat;
194	struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
195
196	twl4030_madc_bat = kzalloc(sizeof(*twl4030_madc_bat), GFP_KERNEL);
197	if (!twl4030_madc_bat)
198		return -ENOMEM;
199
200	twl4030_madc_bat->psy.name = "twl4030_battery";
201	twl4030_madc_bat->psy.type = POWER_SUPPLY_TYPE_BATTERY;
202	twl4030_madc_bat->psy.properties = twl4030_madc_bat_props;
203	twl4030_madc_bat->psy.num_properties =
204					ARRAY_SIZE(twl4030_madc_bat_props);
205	twl4030_madc_bat->psy.get_property = twl4030_madc_bat_get_property;
206	twl4030_madc_bat->psy.external_power_changed =
207					twl4030_madc_bat_ext_changed;
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	platform_set_drvdata(pdev, twl4030_madc_bat);
219	power_supply_register(&pdev->dev, &twl4030_madc_bat->psy);
220
221	return 0;
222}
223
224static int twl4030_madc_battery_remove(struct platform_device *pdev)
225{
226	struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
227
228	power_supply_unregister(&bat->psy);
229	kfree(bat);
230
231	return 0;
232}
233
234static struct platform_driver twl4030_madc_battery_driver = {
235	.driver = {
236		.name = "twl4030_madc_battery",
237	},
238	.probe  = twl4030_madc_battery_probe,
239	.remove = twl4030_madc_battery_remove,
240};
241module_platform_driver(twl4030_madc_battery_driver);
242
243MODULE_LICENSE("GPL");
244MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
245MODULE_DESCRIPTION("twl4030_madc battery driver");
246