1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Generic battery driver using IIO
4  * Copyright (C) 2012, Anish Kumar <anish198519851985@gmail.com>
5  * Copyright (c) 2023, Sebastian Reichel <sre@kernel.org>
6  */
7 #include <linux/interrupt.h>
8 #include <linux/platform_device.h>
9 #include <linux/power_supply.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/err.h>
12 #include <linux/timer.h>
13 #include <linux/jiffies.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/iio/consumer.h>
19 #include <linux/iio/types.h>
20 #include <linux/of.h>
21 #include <linux/devm-helpers.h>
22 
23 #define JITTER_DEFAULT 10 /* hope 10ms is enough */
24 
25 enum gab_chan_type {
26 	GAB_VOLTAGE = 0,
27 	GAB_CURRENT,
28 	GAB_POWER,
29 	GAB_TEMP,
30 	GAB_MAX_CHAN_TYPE
31 };
32 
33 /*
34  * gab_chan_name suggests the standard channel names for commonly used
35  * channel types.
36  */
37 static const char *const gab_chan_name[] = {
38 	[GAB_VOLTAGE]	= "voltage",
39 	[GAB_CURRENT]	= "current",
40 	[GAB_POWER]	= "power",
41 	[GAB_TEMP]	= "temperature",
42 };
43 
44 struct gab {
45 	struct power_supply *psy;
46 	struct power_supply_desc psy_desc;
47 	struct iio_channel *channel[GAB_MAX_CHAN_TYPE];
48 	struct delayed_work bat_work;
49 	int status;
50 	struct gpio_desc *charge_finished;
51 };
52 
to_generic_bat(struct power_supply * psy)53 static struct gab *to_generic_bat(struct power_supply *psy)
54 {
55 	return power_supply_get_drvdata(psy);
56 }
57 
gab_ext_power_changed(struct power_supply * psy)58 static void gab_ext_power_changed(struct power_supply *psy)
59 {
60 	struct gab *adc_bat = to_generic_bat(psy);
61 
62 	schedule_delayed_work(&adc_bat->bat_work, msecs_to_jiffies(0));
63 }
64 
65 static const enum power_supply_property gab_props[] = {
66 	POWER_SUPPLY_PROP_STATUS,
67 };
68 
69 /*
70  * This properties are set based on the received platform data and this
71  * should correspond one-to-one with enum chan_type.
72  */
73 static const enum power_supply_property gab_dyn_props[] = {
74 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
75 	POWER_SUPPLY_PROP_CURRENT_NOW,
76 	POWER_SUPPLY_PROP_POWER_NOW,
77 	POWER_SUPPLY_PROP_TEMP,
78 };
79 
gab_charge_finished(struct gab * adc_bat)80 static bool gab_charge_finished(struct gab *adc_bat)
81 {
82 	if (!adc_bat->charge_finished)
83 		return false;
84 	return gpiod_get_value(adc_bat->charge_finished);
85 }
86 
gab_read_channel(struct gab * adc_bat,enum gab_chan_type channel,int * result)87 static int gab_read_channel(struct gab *adc_bat, enum gab_chan_type channel,
88 		int *result)
89 {
90 	int ret;
91 
92 	ret = iio_read_channel_processed(adc_bat->channel[channel], result);
93 	if (ret < 0)
94 		dev_err(&adc_bat->psy->dev, "read channel error: %d\n", ret);
95 	else
96 		*result *= 1000;
97 
98 	return ret;
99 }
100 
gab_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)101 static int gab_get_property(struct power_supply *psy,
102 		enum power_supply_property psp, union power_supply_propval *val)
103 {
104 	struct gab *adc_bat = to_generic_bat(psy);
105 
106 	switch (psp) {
107 	case POWER_SUPPLY_PROP_STATUS:
108 		val->intval = adc_bat->status;
109 		return 0;
110 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
111 		return gab_read_channel(adc_bat, GAB_VOLTAGE, &val->intval);
112 	case POWER_SUPPLY_PROP_CURRENT_NOW:
113 		return gab_read_channel(adc_bat, GAB_CURRENT, &val->intval);
114 	case POWER_SUPPLY_PROP_POWER_NOW:
115 		return gab_read_channel(adc_bat, GAB_POWER, &val->intval);
116 	case POWER_SUPPLY_PROP_TEMP:
117 		return gab_read_channel(adc_bat, GAB_TEMP, &val->intval);
118 	default:
119 		return -EINVAL;
120 	}
121 }
122 
gab_work(struct work_struct * work)123 static void gab_work(struct work_struct *work)
124 {
125 	struct gab *adc_bat;
126 	struct delayed_work *delayed_work;
127 	int status;
128 
129 	delayed_work = to_delayed_work(work);
130 	adc_bat = container_of(delayed_work, struct gab, bat_work);
131 	status = adc_bat->status;
132 
133 	if (!power_supply_am_i_supplied(adc_bat->psy))
134 		adc_bat->status =  POWER_SUPPLY_STATUS_DISCHARGING;
135 	else if (gab_charge_finished(adc_bat))
136 		adc_bat->status = POWER_SUPPLY_STATUS_NOT_CHARGING;
137 	else
138 		adc_bat->status = POWER_SUPPLY_STATUS_CHARGING;
139 
140 	if (status != adc_bat->status)
141 		power_supply_changed(adc_bat->psy);
142 }
143 
gab_charged(int irq,void * dev_id)144 static irqreturn_t gab_charged(int irq, void *dev_id)
145 {
146 	struct gab *adc_bat = dev_id;
147 
148 	schedule_delayed_work(&adc_bat->bat_work,
149 			      msecs_to_jiffies(JITTER_DEFAULT));
150 
151 	return IRQ_HANDLED;
152 }
153 
gab_probe(struct platform_device * pdev)154 static int gab_probe(struct platform_device *pdev)
155 {
156 	struct gab *adc_bat;
157 	struct power_supply_desc *psy_desc;
158 	struct power_supply_config psy_cfg = {};
159 	enum power_supply_property *properties;
160 	int ret = 0;
161 	int chan;
162 	int index = ARRAY_SIZE(gab_props);
163 	bool any = false;
164 
165 	adc_bat = devm_kzalloc(&pdev->dev, sizeof(*adc_bat), GFP_KERNEL);
166 	if (!adc_bat)
167 		return -ENOMEM;
168 
169 	psy_cfg.of_node = pdev->dev.of_node;
170 	psy_cfg.drv_data = adc_bat;
171 	psy_desc = &adc_bat->psy_desc;
172 	psy_desc->name = dev_name(&pdev->dev);
173 
174 	/* bootup default values for the battery */
175 	adc_bat->status = POWER_SUPPLY_STATUS_DISCHARGING;
176 	psy_desc->type = POWER_SUPPLY_TYPE_BATTERY;
177 	psy_desc->get_property = gab_get_property;
178 	psy_desc->external_power_changed = gab_ext_power_changed;
179 
180 	/*
181 	 * copying the static properties and allocating extra memory for holding
182 	 * the extra configurable properties received from platform data.
183 	 */
184 	properties = devm_kcalloc(&pdev->dev,
185 				  ARRAY_SIZE(gab_props) +
186 				  ARRAY_SIZE(gab_chan_name),
187 				  sizeof(*properties),
188 				  GFP_KERNEL);
189 	if (!properties)
190 		return -ENOMEM;
191 
192 	memcpy(properties, gab_props, sizeof(gab_props));
193 
194 	/*
195 	 * getting channel from iio and copying the battery properties
196 	 * based on the channel supported by consumer device.
197 	 */
198 	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {
199 		adc_bat->channel[chan] = devm_iio_channel_get(&pdev->dev, gab_chan_name[chan]);
200 		if (IS_ERR(adc_bat->channel[chan])) {
201 			ret = PTR_ERR(adc_bat->channel[chan]);
202 			if (ret != -ENODEV)
203 				return dev_err_probe(&pdev->dev, ret, "Failed to get ADC channel %s\n", gab_chan_name[chan]);
204 			adc_bat->channel[chan] = NULL;
205 		} else if (adc_bat->channel[chan]) {
206 			/* copying properties for supported channels only */
207 			int index2;
208 
209 			for (index2 = 0; index2 < index; index2++) {
210 				if (properties[index2] == gab_dyn_props[chan])
211 					break;	/* already known */
212 			}
213 			if (index2 == index)	/* really new */
214 				properties[index++] = gab_dyn_props[chan];
215 			any = true;
216 		}
217 	}
218 
219 	/* none of the channels are supported so let's bail out */
220 	if (!any)
221 		return dev_err_probe(&pdev->dev, -ENODEV, "Failed to get any ADC channel\n");
222 
223 	/*
224 	 * Total number of properties is equal to static properties
225 	 * plus the dynamic properties.Some properties may not be set
226 	 * as come channels may be not be supported by the device.So
227 	 * we need to take care of that.
228 	 */
229 	psy_desc->properties = properties;
230 	psy_desc->num_properties = index;
231 
232 	adc_bat->psy = devm_power_supply_register(&pdev->dev, psy_desc, &psy_cfg);
233 	if (IS_ERR(adc_bat->psy))
234 		return dev_err_probe(&pdev->dev, PTR_ERR(adc_bat->psy), "Failed to register power-supply device\n");
235 
236 	ret = devm_delayed_work_autocancel(&pdev->dev, &adc_bat->bat_work, gab_work);
237 	if (ret)
238 		return dev_err_probe(&pdev->dev, ret, "Failed to register delayed work\n");
239 
240 	adc_bat->charge_finished = devm_gpiod_get_optional(&pdev->dev, "charged", GPIOD_IN);
241 	if (adc_bat->charge_finished) {
242 		int irq;
243 
244 		irq = gpiod_to_irq(adc_bat->charge_finished);
245 		ret = devm_request_any_context_irq(&pdev->dev, irq, gab_charged,
246 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
247 				"battery charged", adc_bat);
248 		if (ret < 0)
249 			return dev_err_probe(&pdev->dev, ret, "Failed to register irq\n");
250 	}
251 
252 	platform_set_drvdata(pdev, adc_bat);
253 
254 	/* Schedule timer to check current status */
255 	schedule_delayed_work(&adc_bat->bat_work,
256 			msecs_to_jiffies(0));
257 	return 0;
258 }
259 
gab_suspend(struct device * dev)260 static int __maybe_unused gab_suspend(struct device *dev)
261 {
262 	struct gab *adc_bat = dev_get_drvdata(dev);
263 
264 	cancel_delayed_work_sync(&adc_bat->bat_work);
265 	adc_bat->status = POWER_SUPPLY_STATUS_UNKNOWN;
266 	return 0;
267 }
268 
gab_resume(struct device * dev)269 static int __maybe_unused gab_resume(struct device *dev)
270 {
271 	struct gab *adc_bat = dev_get_drvdata(dev);
272 
273 	/* Schedule timer to check current status */
274 	schedule_delayed_work(&adc_bat->bat_work,
275 			      msecs_to_jiffies(JITTER_DEFAULT));
276 
277 	return 0;
278 }
279 
280 static SIMPLE_DEV_PM_OPS(gab_pm_ops, gab_suspend, gab_resume);
281 
282 static const struct of_device_id gab_match[] = {
283 	{ .compatible = "adc-battery" },
284 	{ }
285 };
286 MODULE_DEVICE_TABLE(of, gab_match);
287 
288 static struct platform_driver gab_driver = {
289 	.driver		= {
290 		.name	= "generic-adc-battery",
291 		.pm	= &gab_pm_ops,
292 		.of_match_table = gab_match,
293 	},
294 	.probe		= gab_probe,
295 };
296 module_platform_driver(gab_driver);
297 
298 MODULE_AUTHOR("anish kumar <anish198519851985@gmail.com>");
299 MODULE_DESCRIPTION("generic battery driver using IIO");
300 MODULE_LICENSE("GPL");
301