1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
4  *  Driver for chargers which report their online status through a GPIO pin
5  */
6 
7 #include <linux/device.h>
8 #include <linux/init.h>
9 #include <linux/interrupt.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/power_supply.h>
14 #include <linux/slab.h>
15 #include <linux/of.h>
16 #include <linux/gpio/consumer.h>
17 
18 #include <linux/power/gpio-charger.h>
19 
20 struct gpio_mapping {
21 	u32 limit_ua;
22 	u32 gpiodata;
23 } __packed;
24 
25 struct gpio_charger {
26 	struct device *dev;
27 	unsigned int irq;
28 	unsigned int charge_status_irq;
29 	bool wakeup_enabled;
30 
31 	struct power_supply *charger;
32 	struct power_supply_desc charger_desc;
33 	struct gpio_desc *gpiod;
34 	struct gpio_desc *charge_status;
35 
36 	struct gpio_descs *current_limit_gpios;
37 	struct gpio_mapping *current_limit_map;
38 	u32 current_limit_map_size;
39 	u32 charge_current_limit;
40 };
41 
gpio_charger_irq(int irq,void * devid)42 static irqreturn_t gpio_charger_irq(int irq, void *devid)
43 {
44 	struct power_supply *charger = devid;
45 
46 	power_supply_changed(charger);
47 
48 	return IRQ_HANDLED;
49 }
50 
psy_to_gpio_charger(struct power_supply * psy)51 static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
52 {
53 	return power_supply_get_drvdata(psy);
54 }
55 
set_charge_current_limit(struct gpio_charger * gpio_charger,int val)56 static int set_charge_current_limit(struct gpio_charger *gpio_charger, int val)
57 {
58 	struct gpio_mapping mapping;
59 	int ndescs = gpio_charger->current_limit_gpios->ndescs;
60 	struct gpio_desc **gpios = gpio_charger->current_limit_gpios->desc;
61 	int i;
62 
63 	if (!gpio_charger->current_limit_map_size)
64 		return -EINVAL;
65 
66 	for (i = 0; i < gpio_charger->current_limit_map_size; i++) {
67 		if (gpio_charger->current_limit_map[i].limit_ua <= val)
68 			break;
69 	}
70 	mapping = gpio_charger->current_limit_map[i];
71 
72 	for (i = 0; i < ndescs; i++) {
73 		bool val = (mapping.gpiodata >> i) & 1;
74 		gpiod_set_value_cansleep(gpios[ndescs-i-1], val);
75 	}
76 
77 	gpio_charger->charge_current_limit = mapping.limit_ua;
78 
79 	dev_dbg(gpio_charger->dev, "set charge current limit to %d (requested: %d)\n",
80 		gpio_charger->charge_current_limit, val);
81 
82 	return 0;
83 }
84 
gpio_charger_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)85 static int gpio_charger_get_property(struct power_supply *psy,
86 		enum power_supply_property psp, union power_supply_propval *val)
87 {
88 	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
89 
90 	switch (psp) {
91 	case POWER_SUPPLY_PROP_ONLINE:
92 		val->intval = gpiod_get_value_cansleep(gpio_charger->gpiod);
93 		break;
94 	case POWER_SUPPLY_PROP_STATUS:
95 		if (gpiod_get_value_cansleep(gpio_charger->charge_status))
96 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
97 		else
98 			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
99 		break;
100 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
101 		val->intval = gpio_charger->charge_current_limit;
102 		break;
103 	default:
104 		return -EINVAL;
105 	}
106 
107 	return 0;
108 }
109 
gpio_charger_set_property(struct power_supply * psy,enum power_supply_property psp,const union power_supply_propval * val)110 static int gpio_charger_set_property(struct power_supply *psy,
111 	enum power_supply_property psp, const union power_supply_propval *val)
112 {
113 	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
114 
115 	switch (psp) {
116 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
117 		return set_charge_current_limit(gpio_charger, val->intval);
118 	default:
119 		return -EINVAL;
120 	}
121 
122 	return 0;
123 }
124 
gpio_charger_property_is_writeable(struct power_supply * psy,enum power_supply_property psp)125 static int gpio_charger_property_is_writeable(struct power_supply *psy,
126 					      enum power_supply_property psp)
127 {
128 	switch (psp) {
129 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
130 		return 1;
131 	default:
132 		break;
133 	}
134 
135 	return 0;
136 }
137 
gpio_charger_get_type(struct device * dev)138 static enum power_supply_type gpio_charger_get_type(struct device *dev)
139 {
140 	const char *chargetype;
141 
142 	if (!device_property_read_string(dev, "charger-type", &chargetype)) {
143 		if (!strcmp("unknown", chargetype))
144 			return POWER_SUPPLY_TYPE_UNKNOWN;
145 		if (!strcmp("battery", chargetype))
146 			return POWER_SUPPLY_TYPE_BATTERY;
147 		if (!strcmp("ups", chargetype))
148 			return POWER_SUPPLY_TYPE_UPS;
149 		if (!strcmp("mains", chargetype))
150 			return POWER_SUPPLY_TYPE_MAINS;
151 		if (!strcmp("usb-sdp", chargetype))
152 			return POWER_SUPPLY_TYPE_USB;
153 		if (!strcmp("usb-dcp", chargetype))
154 			return POWER_SUPPLY_TYPE_USB;
155 		if (!strcmp("usb-cdp", chargetype))
156 			return POWER_SUPPLY_TYPE_USB;
157 		if (!strcmp("usb-aca", chargetype))
158 			return POWER_SUPPLY_TYPE_USB;
159 	}
160 	dev_warn(dev, "unknown charger type %s\n", chargetype);
161 
162 	return POWER_SUPPLY_TYPE_UNKNOWN;
163 }
164 
gpio_charger_get_irq(struct device * dev,void * dev_id,struct gpio_desc * gpio)165 static int gpio_charger_get_irq(struct device *dev, void *dev_id,
166 				struct gpio_desc *gpio)
167 {
168 	int ret, irq = gpiod_to_irq(gpio);
169 
170 	if (irq > 0) {
171 		ret = devm_request_any_context_irq(dev, irq, gpio_charger_irq,
172 						   IRQF_TRIGGER_RISING |
173 						   IRQF_TRIGGER_FALLING,
174 						   dev_name(dev),
175 						   dev_id);
176 		if (ret < 0) {
177 			dev_warn(dev, "Failed to request irq: %d\n", ret);
178 			irq = 0;
179 		}
180 	}
181 
182 	return irq;
183 }
184 
init_charge_current_limit(struct device * dev,struct gpio_charger * gpio_charger)185 static int init_charge_current_limit(struct device *dev,
186 				    struct gpio_charger *gpio_charger)
187 {
188 	int i, len;
189 	u32 cur_limit = U32_MAX;
190 
191 	gpio_charger->current_limit_gpios = devm_gpiod_get_array_optional(dev,
192 		"charge-current-limit", GPIOD_OUT_LOW);
193 	if (IS_ERR(gpio_charger->current_limit_gpios)) {
194 		dev_err(dev, "error getting current-limit GPIOs\n");
195 		return PTR_ERR(gpio_charger->current_limit_gpios);
196 	}
197 
198 	if (!gpio_charger->current_limit_gpios)
199 		return 0;
200 
201 	len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
202 		NULL, 0);
203 	if (len < 0)
204 		return len;
205 
206 	if (len == 0 || len % 2) {
207 		dev_err(dev, "invalid charge-current-limit-mapping length\n");
208 		return -EINVAL;
209 	}
210 
211 	gpio_charger->current_limit_map = devm_kmalloc_array(dev,
212 		len / 2, sizeof(*gpio_charger->current_limit_map), GFP_KERNEL);
213 	if (!gpio_charger->current_limit_map)
214 		return -ENOMEM;
215 
216 	gpio_charger->current_limit_map_size = len / 2;
217 
218 	len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
219 		(u32*) gpio_charger->current_limit_map, len);
220 	if (len < 0)
221 		return len;
222 
223 	for (i=0; i < gpio_charger->current_limit_map_size; i++) {
224 		if (gpio_charger->current_limit_map[i].limit_ua > cur_limit) {
225 			dev_err(dev, "charge-current-limit-mapping not sorted by current in descending order\n");
226 			return -EINVAL;
227 		}
228 
229 		cur_limit = gpio_charger->current_limit_map[i].limit_ua;
230 	}
231 
232 	/* default to smallest current limitation for safety reasons */
233 	len = gpio_charger->current_limit_map_size - 1;
234 	set_charge_current_limit(gpio_charger,
235 		gpio_charger->current_limit_map[len].limit_ua);
236 
237 	return 0;
238 }
239 
240 /*
241  * The entries will be overwritten by driver's probe routine depending
242  * on the available features. This list ensures, that the array is big
243  * enough for all optional features.
244  */
245 static enum power_supply_property gpio_charger_properties[] = {
246 	POWER_SUPPLY_PROP_ONLINE,
247 	POWER_SUPPLY_PROP_STATUS,
248 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
249 };
250 
gpio_charger_probe(struct platform_device * pdev)251 static int gpio_charger_probe(struct platform_device *pdev)
252 {
253 	struct device *dev = &pdev->dev;
254 	const struct gpio_charger_platform_data *pdata = dev->platform_data;
255 	struct power_supply_config psy_cfg = {};
256 	struct gpio_charger *gpio_charger;
257 	struct power_supply_desc *charger_desc;
258 	struct gpio_desc *charge_status;
259 	int charge_status_irq;
260 	int ret;
261 	int num_props = 0;
262 
263 	if (!pdata && !dev->of_node) {
264 		dev_err(dev, "No platform data\n");
265 		return -ENOENT;
266 	}
267 
268 	gpio_charger = devm_kzalloc(dev, sizeof(*gpio_charger), GFP_KERNEL);
269 	if (!gpio_charger)
270 		return -ENOMEM;
271 	gpio_charger->dev = dev;
272 
273 	/*
274 	 * This will fetch a GPIO descriptor from device tree, ACPI or
275 	 * boardfile descriptor tables. It's good to try this first.
276 	 */
277 	gpio_charger->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
278 	if (IS_ERR(gpio_charger->gpiod)) {
279 		/* Just try again if this happens */
280 		return dev_err_probe(dev, PTR_ERR(gpio_charger->gpiod),
281 				     "error getting GPIO descriptor\n");
282 	}
283 
284 	if (gpio_charger->gpiod) {
285 		gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_ONLINE;
286 		num_props++;
287 	}
288 
289 	charge_status = devm_gpiod_get_optional(dev, "charge-status", GPIOD_IN);
290 	if (IS_ERR(charge_status))
291 		return PTR_ERR(charge_status);
292 	if (charge_status) {
293 		gpio_charger->charge_status = charge_status;
294 		gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_STATUS;
295 		num_props++;
296 	}
297 
298 	ret = init_charge_current_limit(dev, gpio_charger);
299 	if (ret < 0)
300 		return ret;
301 	if (gpio_charger->current_limit_map) {
302 		gpio_charger_properties[num_props] =
303 			POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;
304 		num_props++;
305 	}
306 
307 	charger_desc = &gpio_charger->charger_desc;
308 	charger_desc->properties = gpio_charger_properties;
309 	charger_desc->num_properties = num_props;
310 	charger_desc->get_property = gpio_charger_get_property;
311 	charger_desc->set_property = gpio_charger_set_property;
312 	charger_desc->property_is_writeable =
313 					gpio_charger_property_is_writeable;
314 
315 	psy_cfg.of_node = dev->of_node;
316 	psy_cfg.drv_data = gpio_charger;
317 
318 	if (pdata) {
319 		charger_desc->name = pdata->name;
320 		charger_desc->type = pdata->type;
321 		psy_cfg.supplied_to = pdata->supplied_to;
322 		psy_cfg.num_supplicants = pdata->num_supplicants;
323 	} else {
324 		charger_desc->name = dev->of_node->name;
325 		charger_desc->type = gpio_charger_get_type(dev);
326 	}
327 
328 	if (!charger_desc->name)
329 		charger_desc->name = pdev->name;
330 
331 	gpio_charger->charger = devm_power_supply_register(dev, charger_desc,
332 							   &psy_cfg);
333 	if (IS_ERR(gpio_charger->charger)) {
334 		ret = PTR_ERR(gpio_charger->charger);
335 		dev_err(dev, "Failed to register power supply: %d\n", ret);
336 		return ret;
337 	}
338 
339 	gpio_charger->irq = gpio_charger_get_irq(dev, gpio_charger->charger,
340 						 gpio_charger->gpiod);
341 
342 	charge_status_irq = gpio_charger_get_irq(dev, gpio_charger->charger,
343 						 gpio_charger->charge_status);
344 	gpio_charger->charge_status_irq = charge_status_irq;
345 
346 	platform_set_drvdata(pdev, gpio_charger);
347 
348 	device_init_wakeup(dev, 1);
349 
350 	return 0;
351 }
352 
353 #ifdef CONFIG_PM_SLEEP
gpio_charger_suspend(struct device * dev)354 static int gpio_charger_suspend(struct device *dev)
355 {
356 	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
357 
358 	if (device_may_wakeup(dev))
359 		gpio_charger->wakeup_enabled =
360 			!enable_irq_wake(gpio_charger->irq);
361 
362 	return 0;
363 }
364 
gpio_charger_resume(struct device * dev)365 static int gpio_charger_resume(struct device *dev)
366 {
367 	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
368 
369 	if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled)
370 		disable_irq_wake(gpio_charger->irq);
371 	power_supply_changed(gpio_charger->charger);
372 
373 	return 0;
374 }
375 #endif
376 
377 static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
378 		gpio_charger_suspend, gpio_charger_resume);
379 
380 static const struct of_device_id gpio_charger_match[] = {
381 	{ .compatible = "gpio-charger" },
382 	{ }
383 };
384 MODULE_DEVICE_TABLE(of, gpio_charger_match);
385 
386 static struct platform_driver gpio_charger_driver = {
387 	.probe = gpio_charger_probe,
388 	.driver = {
389 		.name = "gpio-charger",
390 		.pm = &gpio_charger_pm_ops,
391 		.of_match_table = gpio_charger_match,
392 	},
393 };
394 
395 module_platform_driver(gpio_charger_driver);
396 
397 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
398 MODULE_DESCRIPTION("Driver for chargers only communicating via GPIO(s)");
399 MODULE_LICENSE("GPL");
400 MODULE_ALIAS("platform:gpio-charger");
401