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
20struct gpio_mapping {
21	u32 limit_ua;
22	u32 gpiodata;
23} __packed;
24
25struct 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
42static 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
51static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
52{
53	return power_supply_get_drvdata(psy);
54}
55
56static 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
85static 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
110static 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
125static 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
138static 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
165static 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
185static 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 */
245static 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
251static 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
354static 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
365static 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
377static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
378		gpio_charger_suspend, gpio_charger_resume);
379
380static const struct of_device_id gpio_charger_match[] = {
381	{ .compatible = "gpio-charger" },
382	{ }
383};
384MODULE_DEVICE_TABLE(of, gpio_charger_match);
385
386static 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
395module_platform_driver(gpio_charger_driver);
396
397MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
398MODULE_DESCRIPTION("Driver for chargers only communicating via GPIO(s)");
399MODULE_LICENSE("GPL");
400MODULE_ALIAS("platform:gpio-charger");
401