1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Battery measurement code for WM97xx
4  *
5  * based on tosa_battery.c
6  *
7  * Copyright (C) 2008 Marek Vasut <marek.vasut@gmail.com>
8  */
9 
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/power_supply.h>
15 #include <linux/wm97xx.h>
16 #include <linux/spinlock.h>
17 #include <linux/interrupt.h>
18 #include <linux/gpio/consumer.h>
19 #include <linux/irq.h>
20 #include <linux/slab.h>
21 
22 static struct work_struct bat_work;
23 static struct gpio_desc *charge_gpiod;
24 static DEFINE_MUTEX(work_lock);
25 static int bat_status = POWER_SUPPLY_STATUS_UNKNOWN;
26 static enum power_supply_property *prop;
27 
28 static unsigned long wm97xx_read_bat(struct power_supply *bat_ps)
29 {
30 	struct wm97xx_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);
31 
32 	return wm97xx_read_aux_adc(dev_get_drvdata(bat_ps->dev.parent),
33 					pdata->batt_aux) * pdata->batt_mult /
34 					pdata->batt_div;
35 }
36 
37 static unsigned long wm97xx_read_temp(struct power_supply *bat_ps)
38 {
39 	struct wm97xx_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);
40 
41 	return wm97xx_read_aux_adc(dev_get_drvdata(bat_ps->dev.parent),
42 					pdata->temp_aux) * pdata->temp_mult /
43 					pdata->temp_div;
44 }
45 
46 static int wm97xx_bat_get_property(struct power_supply *bat_ps,
47 			    enum power_supply_property psp,
48 			    union power_supply_propval *val)
49 {
50 	struct wm97xx_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);
51 
52 	switch (psp) {
53 	case POWER_SUPPLY_PROP_STATUS:
54 		val->intval = bat_status;
55 		break;
56 	case POWER_SUPPLY_PROP_TECHNOLOGY:
57 		val->intval = pdata->batt_tech;
58 		break;
59 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
60 		if (pdata->batt_aux >= 0)
61 			val->intval = wm97xx_read_bat(bat_ps);
62 		else
63 			return -EINVAL;
64 		break;
65 	case POWER_SUPPLY_PROP_TEMP:
66 		if (pdata->temp_aux >= 0)
67 			val->intval = wm97xx_read_temp(bat_ps);
68 		else
69 			return -EINVAL;
70 		break;
71 	case POWER_SUPPLY_PROP_VOLTAGE_MAX:
72 		if (pdata->max_voltage >= 0)
73 			val->intval = pdata->max_voltage;
74 		else
75 			return -EINVAL;
76 		break;
77 	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
78 		if (pdata->min_voltage >= 0)
79 			val->intval = pdata->min_voltage;
80 		else
81 			return -EINVAL;
82 		break;
83 	case POWER_SUPPLY_PROP_PRESENT:
84 		val->intval = 1;
85 		break;
86 	default:
87 		return -EINVAL;
88 	}
89 	return 0;
90 }
91 
92 static void wm97xx_bat_external_power_changed(struct power_supply *bat_ps)
93 {
94 	schedule_work(&bat_work);
95 }
96 
97 static void wm97xx_bat_update(struct power_supply *bat_ps)
98 {
99 	int old_status = bat_status;
100 
101 	mutex_lock(&work_lock);
102 
103 	bat_status = (charge_gpiod) ?
104 			(gpiod_get_value(charge_gpiod) ?
105 			POWER_SUPPLY_STATUS_DISCHARGING :
106 			POWER_SUPPLY_STATUS_CHARGING) :
107 			POWER_SUPPLY_STATUS_UNKNOWN;
108 
109 	if (old_status != bat_status) {
110 		pr_debug("%s: %i -> %i\n", bat_ps->desc->name, old_status,
111 					bat_status);
112 		power_supply_changed(bat_ps);
113 	}
114 
115 	mutex_unlock(&work_lock);
116 }
117 
118 static struct power_supply *bat_psy;
119 static struct power_supply_desc bat_psy_desc = {
120 	.type			= POWER_SUPPLY_TYPE_BATTERY,
121 	.get_property		= wm97xx_bat_get_property,
122 	.external_power_changed = wm97xx_bat_external_power_changed,
123 	.use_for_apm		= 1,
124 };
125 
126 static void wm97xx_bat_work(struct work_struct *work)
127 {
128 	wm97xx_bat_update(bat_psy);
129 }
130 
131 static irqreturn_t wm97xx_chrg_irq(int irq, void *data)
132 {
133 	schedule_work(&bat_work);
134 	return IRQ_HANDLED;
135 }
136 
137 #ifdef CONFIG_PM
138 static int wm97xx_bat_suspend(struct device *dev)
139 {
140 	flush_work(&bat_work);
141 	return 0;
142 }
143 
144 static int wm97xx_bat_resume(struct device *dev)
145 {
146 	schedule_work(&bat_work);
147 	return 0;
148 }
149 
150 static const struct dev_pm_ops wm97xx_bat_pm_ops = {
151 	.suspend	= wm97xx_bat_suspend,
152 	.resume		= wm97xx_bat_resume,
153 };
154 #endif
155 
156 static int wm97xx_bat_probe(struct platform_device *dev)
157 {
158 	int ret = 0;
159 	int props = 1;	/* POWER_SUPPLY_PROP_PRESENT */
160 	int i = 0;
161 	struct wm97xx_batt_pdata *pdata = dev->dev.platform_data;
162 	struct power_supply_config cfg = {};
163 
164 	if (!pdata) {
165 		dev_err(&dev->dev, "No platform data supplied\n");
166 		return -EINVAL;
167 	}
168 
169 	cfg.drv_data = pdata;
170 
171 	if (dev->id != -1)
172 		return -EINVAL;
173 
174 	charge_gpiod = devm_gpiod_get_optional(&dev->dev, NULL, GPIOD_IN);
175 	if (IS_ERR(charge_gpiod))
176 		return dev_err_probe(&dev->dev,
177 				     PTR_ERR(charge_gpiod),
178 				     "failed to get charge GPIO\n");
179 	if (charge_gpiod) {
180 		gpiod_set_consumer_name(charge_gpiod, "BATT CHRG");
181 		ret = request_irq(gpiod_to_irq(charge_gpiod),
182 				wm97xx_chrg_irq, 0,
183 				"AC Detect", dev);
184 		if (ret)
185 			return dev_err_probe(&dev->dev, ret,
186 					     "failed to request GPIO irq\n");
187 		props++;	/* POWER_SUPPLY_PROP_STATUS */
188 	}
189 
190 	if (pdata->batt_tech >= 0)
191 		props++;	/* POWER_SUPPLY_PROP_TECHNOLOGY */
192 	if (pdata->temp_aux >= 0)
193 		props++;	/* POWER_SUPPLY_PROP_TEMP */
194 	if (pdata->batt_aux >= 0)
195 		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_NOW */
196 	if (pdata->max_voltage >= 0)
197 		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_MAX */
198 	if (pdata->min_voltage >= 0)
199 		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_MIN */
200 
201 	prop = kcalloc(props, sizeof(*prop), GFP_KERNEL);
202 	if (!prop) {
203 		ret = -ENOMEM;
204 		goto err3;
205 	}
206 
207 	prop[i++] = POWER_SUPPLY_PROP_PRESENT;
208 	if (charge_gpiod)
209 		prop[i++] = POWER_SUPPLY_PROP_STATUS;
210 	if (pdata->batt_tech >= 0)
211 		prop[i++] = POWER_SUPPLY_PROP_TECHNOLOGY;
212 	if (pdata->temp_aux >= 0)
213 		prop[i++] = POWER_SUPPLY_PROP_TEMP;
214 	if (pdata->batt_aux >= 0)
215 		prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_NOW;
216 	if (pdata->max_voltage >= 0)
217 		prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MAX;
218 	if (pdata->min_voltage >= 0)
219 		prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MIN;
220 
221 	INIT_WORK(&bat_work, wm97xx_bat_work);
222 
223 	if (!pdata->batt_name) {
224 		dev_info(&dev->dev, "Please consider setting proper battery "
225 				"name in platform definition file, falling "
226 				"back to name \"wm97xx-batt\"\n");
227 		bat_psy_desc.name = "wm97xx-batt";
228 	} else
229 		bat_psy_desc.name = pdata->batt_name;
230 
231 	bat_psy_desc.properties = prop;
232 	bat_psy_desc.num_properties = props;
233 
234 	bat_psy = power_supply_register(&dev->dev, &bat_psy_desc, &cfg);
235 	if (!IS_ERR(bat_psy)) {
236 		schedule_work(&bat_work);
237 	} else {
238 		ret = PTR_ERR(bat_psy);
239 		goto err4;
240 	}
241 
242 	return 0;
243 err4:
244 	kfree(prop);
245 err3:
246 	if (charge_gpiod)
247 		free_irq(gpiod_to_irq(charge_gpiod), dev);
248 	return ret;
249 }
250 
251 static int wm97xx_bat_remove(struct platform_device *dev)
252 {
253 	if (charge_gpiod)
254 		free_irq(gpiod_to_irq(charge_gpiod), dev);
255 	cancel_work_sync(&bat_work);
256 	power_supply_unregister(bat_psy);
257 	kfree(prop);
258 	return 0;
259 }
260 
261 static struct platform_driver wm97xx_bat_driver = {
262 	.driver	= {
263 		.name	= "wm97xx-battery",
264 #ifdef CONFIG_PM
265 		.pm	= &wm97xx_bat_pm_ops,
266 #endif
267 	},
268 	.probe		= wm97xx_bat_probe,
269 	.remove		= wm97xx_bat_remove,
270 };
271 
272 module_platform_driver(wm97xx_bat_driver);
273 
274 MODULE_LICENSE("GPL");
275 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
276 MODULE_DESCRIPTION("WM97xx battery driver");
277