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 
24 struct 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 
32 static 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 
madc_read(struct iio_channel * channel)45 static 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 
twl4030_madc_bat_get_charging_status(struct twl4030_madc_battery * bt)55 static 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 
twl4030_madc_bat_get_voltage(struct twl4030_madc_battery * bt)60 static int twl4030_madc_bat_get_voltage(struct twl4030_madc_battery *bt)
61 {
62 	return madc_read(bt->channel_vbat);
63 }
64 
twl4030_madc_bat_get_current(struct twl4030_madc_battery * bt)65 static int twl4030_madc_bat_get_current(struct twl4030_madc_battery *bt)
66 {
67 	return madc_read(bt->channel_ichg) * 1000;
68 }
69 
twl4030_madc_bat_get_temp(struct twl4030_madc_battery * bt)70 static int twl4030_madc_bat_get_temp(struct twl4030_madc_battery *bt)
71 {
72 	return madc_read(bt->channel_temp) * 10;
73 }
74 
twl4030_madc_bat_voltscale(struct twl4030_madc_battery * bat,int volt)75 static 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 
twl4030_madc_bat_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)107 static 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 
171 static 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 
twl4030_cmp(const void * a,const void * b)180 static 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 
twl4030_madc_battery_probe(struct platform_device * pdev)186 static 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 	int ret = 0;
192 
193 	twl4030_madc_bat = devm_kzalloc(&pdev->dev, sizeof(*twl4030_madc_bat),
194 				GFP_KERNEL);
195 	if (!twl4030_madc_bat)
196 		return -ENOMEM;
197 
198 	twl4030_madc_bat->channel_temp = iio_channel_get(&pdev->dev, "temp");
199 	if (IS_ERR(twl4030_madc_bat->channel_temp)) {
200 		ret = PTR_ERR(twl4030_madc_bat->channel_temp);
201 		goto err;
202 	}
203 
204 	twl4030_madc_bat->channel_ichg = iio_channel_get(&pdev->dev, "ichg");
205 	if (IS_ERR(twl4030_madc_bat->channel_ichg)) {
206 		ret = PTR_ERR(twl4030_madc_bat->channel_ichg);
207 		goto err_temp;
208 	}
209 
210 	twl4030_madc_bat->channel_vbat = iio_channel_get(&pdev->dev, "vbat");
211 	if (IS_ERR(twl4030_madc_bat->channel_vbat)) {
212 		ret = PTR_ERR(twl4030_madc_bat->channel_vbat);
213 		goto err_ichg;
214 	}
215 
216 	/* sort charging and discharging calibration data */
217 	sort(pdata->charging, pdata->charging_size,
218 		sizeof(struct twl4030_madc_bat_calibration),
219 		twl4030_cmp, NULL);
220 	sort(pdata->discharging, pdata->discharging_size,
221 		sizeof(struct twl4030_madc_bat_calibration),
222 		twl4030_cmp, NULL);
223 
224 	twl4030_madc_bat->pdata = pdata;
225 	platform_set_drvdata(pdev, twl4030_madc_bat);
226 	psy_cfg.drv_data = twl4030_madc_bat;
227 	twl4030_madc_bat->psy = power_supply_register(&pdev->dev,
228 						      &twl4030_madc_bat_desc,
229 						      &psy_cfg);
230 	if (IS_ERR(twl4030_madc_bat->psy)) {
231 		ret = PTR_ERR(twl4030_madc_bat->psy);
232 		goto err_vbat;
233 	}
234 
235 	return 0;
236 
237 err_vbat:
238 	iio_channel_release(twl4030_madc_bat->channel_vbat);
239 err_ichg:
240 	iio_channel_release(twl4030_madc_bat->channel_ichg);
241 err_temp:
242 	iio_channel_release(twl4030_madc_bat->channel_temp);
243 err:
244 	return ret;
245 }
246 
twl4030_madc_battery_remove(struct platform_device * pdev)247 static int twl4030_madc_battery_remove(struct platform_device *pdev)
248 {
249 	struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
250 
251 	power_supply_unregister(bat->psy);
252 
253 	iio_channel_release(bat->channel_vbat);
254 	iio_channel_release(bat->channel_ichg);
255 	iio_channel_release(bat->channel_temp);
256 
257 	return 0;
258 }
259 
260 static struct platform_driver twl4030_madc_battery_driver = {
261 	.driver = {
262 		.name = "twl4030_madc_battery",
263 	},
264 	.probe  = twl4030_madc_battery_probe,
265 	.remove = twl4030_madc_battery_remove,
266 };
267 module_platform_driver(twl4030_madc_battery_driver);
268 
269 MODULE_LICENSE("GPL");
270 MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
271 MODULE_DESCRIPTION("twl4030_madc battery driver");
272 MODULE_ALIAS("platform:twl4030_madc_battery");
273