gpio-charger.c

  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
 71	/*
 72	 * If a valid charge current limit isn't found, default to smallest
 73	 * current limitation for safety reasons.
 74	 */
 75	if (i >= gpio_charger->current_limit_map_size)
 76		i = gpio_charger->current_limit_map_size - 1;
 77
 78	mapping = gpio_charger->current_limit_map[i];
 79
 80	for (i = 0; i < ndescs; i++) {
 81		bool val = (mapping.gpiodata >> i) & 1;
 82
 83		gpiod_set_value_cansleep(gpios[ndescs - i - 1], val);
 84	}
 85
 86	gpio_charger->charge_current_limit = mapping.limit_ua;
 87
 88	dev_dbg(gpio_charger->dev, "set charge current limit to %d (requested: %d)\n",
 89		gpio_charger->charge_current_limit, val);
 90
 91	return 0;
 92}
 93
 94static int gpio_charger_get_property(struct power_supply *psy,
 95		enum power_supply_property psp, union power_supply_propval *val)
 96{
 97	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
 98
 99	switch (psp) {
100	case POWER_SUPPLY_PROP_ONLINE:
101		val->intval = gpiod_get_value_cansleep(gpio_charger->gpiod);
102		break;
103	case POWER_SUPPLY_PROP_STATUS:
104		if (gpiod_get_value_cansleep(gpio_charger->charge_status))
105			val->intval = POWER_SUPPLY_STATUS_CHARGING;
106		else
107			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
108		break;
109	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
110		val->intval = gpio_charger->charge_current_limit;
111		break;
112	default:
113		return -EINVAL;
114	}
115
116	return 0;
117}
118
119static int gpio_charger_set_property(struct power_supply *psy,
120	enum power_supply_property psp, const union power_supply_propval *val)
121{
122	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
123
124	switch (psp) {
125	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
126		return set_charge_current_limit(gpio_charger, val->intval);
127	default:
128		return -EINVAL;
129	}
130
131	return 0;
132}
133
134static int gpio_charger_property_is_writeable(struct power_supply *psy,
135					      enum power_supply_property psp)
136{
137	switch (psp) {
138	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
139		return 1;
140	default:
141		break;
142	}
143
144	return 0;
145}
146
147static enum power_supply_type gpio_charger_get_type(struct device *dev)
148{
149	const char *chargetype;
150
151	if (!device_property_read_string(dev, "charger-type", &chargetype)) {
152		if (!strcmp("unknown", chargetype))
153			return POWER_SUPPLY_TYPE_UNKNOWN;
154		if (!strcmp("battery", chargetype))
155			return POWER_SUPPLY_TYPE_BATTERY;
156		if (!strcmp("ups", chargetype))
157			return POWER_SUPPLY_TYPE_UPS;
158		if (!strcmp("mains", chargetype))
159			return POWER_SUPPLY_TYPE_MAINS;
160		if (!strcmp("usb-sdp", chargetype))
161			return POWER_SUPPLY_TYPE_USB;
162		if (!strcmp("usb-dcp", chargetype))
163			return POWER_SUPPLY_TYPE_USB;
164		if (!strcmp("usb-cdp", chargetype))
165			return POWER_SUPPLY_TYPE_USB;
166		if (!strcmp("usb-aca", chargetype))
167			return POWER_SUPPLY_TYPE_USB;
168	}
169	dev_warn(dev, "unknown charger type %s\n", chargetype);
170
171	return POWER_SUPPLY_TYPE_UNKNOWN;
172}
173
174static int gpio_charger_get_irq(struct device *dev, void *dev_id,
175				struct gpio_desc *gpio)
176{
177	int ret, irq = gpiod_to_irq(gpio);
178
179	if (irq > 0) {
180		ret = devm_request_any_context_irq(dev, irq, gpio_charger_irq,
181						   IRQF_TRIGGER_RISING |
182						   IRQF_TRIGGER_FALLING,
183						   dev_name(dev),
184						   dev_id);
185		if (ret < 0) {
186			dev_warn(dev, "Failed to request irq: %d\n", ret);
187			irq = 0;
188		}
189	}
190
191	return irq;
192}
193
194static int init_charge_current_limit(struct device *dev,
195				    struct gpio_charger *gpio_charger)
196{
197	int i, len;
198	u32 cur_limit = U32_MAX;
199	bool set_def_limit;
200	u32 def_limit;
201
202	gpio_charger->current_limit_gpios = devm_gpiod_get_array_optional(dev,
203		"charge-current-limit", GPIOD_OUT_LOW);
204	if (IS_ERR(gpio_charger->current_limit_gpios)) {
205		dev_err(dev, "error getting current-limit GPIOs\n");
206		return PTR_ERR(gpio_charger->current_limit_gpios);
207	}
208
209	if (!gpio_charger->current_limit_gpios)
210		return 0;
211
212	len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
213		NULL, 0);
214	if (len < 0)
215		return len;
216
217	if (len == 0 || len % 2) {
218		dev_err(dev, "invalid charge-current-limit-mapping length\n");
219		return -EINVAL;
220	}
221
222	gpio_charger->current_limit_map = devm_kmalloc_array(dev,
223		len / 2, sizeof(*gpio_charger->current_limit_map), GFP_KERNEL);
224	if (!gpio_charger->current_limit_map)
225		return -ENOMEM;
226
227	gpio_charger->current_limit_map_size = len / 2;
228
229	len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
230		(u32 *) gpio_charger->current_limit_map, len);
231	if (len < 0)
232		return len;
233
234	set_def_limit = !device_property_read_u32(dev,
235						  "charge-current-limit-default-microamp",
236						  &def_limit);
237	for (i = 0; i < gpio_charger->current_limit_map_size; i++) {
238		if (gpio_charger->current_limit_map[i].limit_ua > cur_limit) {
239			dev_err(dev, "charge-current-limit-mapping not sorted by current in descending order\n");
240			return -EINVAL;
241		}
242
243		cur_limit = gpio_charger->current_limit_map[i].limit_ua;
244		if (set_def_limit && def_limit == cur_limit) {
245			set_charge_current_limit(gpio_charger, cur_limit);
246			return 0;
247		}
248	}
249
250	if (set_def_limit)
251		dev_warn(dev, "charge-current-limit-default-microamp %u not listed in charge-current-limit-mapping\n",
252			 def_limit);
253
254	/* default to smallest current limitation for safety reasons */
255	len = gpio_charger->current_limit_map_size - 1;
256	set_charge_current_limit(gpio_charger,
257		gpio_charger->current_limit_map[len].limit_ua);
258
259	return 0;
260}
261
262/*
263 * The entries will be overwritten by driver's probe routine depending
264 * on the available features. This list ensures, that the array is big
265 * enough for all optional features.
266 */
267static enum power_supply_property gpio_charger_properties[] = {
268	POWER_SUPPLY_PROP_ONLINE,
269	POWER_SUPPLY_PROP_STATUS,
270	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
271};
272
273static int gpio_charger_probe(struct platform_device *pdev)
274{
275	struct device *dev = &pdev->dev;
276	const struct gpio_charger_platform_data *pdata = dev->platform_data;
277	struct power_supply_config psy_cfg = {};
278	struct gpio_charger *gpio_charger;
279	struct power_supply_desc *charger_desc;
280	struct gpio_desc *charge_status;
281	int charge_status_irq;
282	int ret;
283	int num_props = 0;
284
285	if (!pdata && !dev->of_node) {
286		dev_err(dev, "No platform data\n");
287		return -ENOENT;
288	}
289
290	gpio_charger = devm_kzalloc(dev, sizeof(*gpio_charger), GFP_KERNEL);
291	if (!gpio_charger)
292		return -ENOMEM;
293	gpio_charger->dev = dev;
294
295	/*
296	 * This will fetch a GPIO descriptor from device tree, ACPI or
297	 * boardfile descriptor tables. It's good to try this first.
298	 */
299	gpio_charger->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
300	if (IS_ERR(gpio_charger->gpiod)) {
301		/* Just try again if this happens */
302		return dev_err_probe(dev, PTR_ERR(gpio_charger->gpiod),
303				     "error getting GPIO descriptor\n");
304	}
305
306	if (gpio_charger->gpiod) {
307		gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_ONLINE;
308		num_props++;
309	}
310
311	charge_status = devm_gpiod_get_optional(dev, "charge-status", GPIOD_IN);
312	if (IS_ERR(charge_status))
313		return PTR_ERR(charge_status);
314	if (charge_status) {
315		gpio_charger->charge_status = charge_status;
316		gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_STATUS;
317		num_props++;
318	}
319
320	ret = init_charge_current_limit(dev, gpio_charger);
321	if (ret < 0)
322		return ret;
323	if (gpio_charger->current_limit_map) {
324		gpio_charger_properties[num_props] =
325			POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;
326		num_props++;
327	}
328
329	charger_desc = &gpio_charger->charger_desc;
330	charger_desc->properties = gpio_charger_properties;
331	charger_desc->num_properties = num_props;
332	charger_desc->get_property = gpio_charger_get_property;
333	charger_desc->set_property = gpio_charger_set_property;
334	charger_desc->property_is_writeable =
335					gpio_charger_property_is_writeable;
336
337	psy_cfg.fwnode = dev_fwnode(dev);
338	psy_cfg.drv_data = gpio_charger;
339
340	if (pdata) {
341		charger_desc->name = pdata->name;
342		charger_desc->type = pdata->type;
343		psy_cfg.supplied_to = pdata->supplied_to;
344		psy_cfg.num_supplicants = pdata->num_supplicants;
345	} else {
346		charger_desc->name = dev->of_node->name;
347		charger_desc->type = gpio_charger_get_type(dev);
348	}
349
350	if (!charger_desc->name)
351		charger_desc->name = pdev->name;
352
353	gpio_charger->charger = devm_power_supply_register(dev, charger_desc,
354							   &psy_cfg);
355	if (IS_ERR(gpio_charger->charger)) {
356		ret = PTR_ERR(gpio_charger->charger);
357		dev_err(dev, "Failed to register power supply: %d\n", ret);
358		return ret;
359	}
360
361	gpio_charger->irq = gpio_charger_get_irq(dev, gpio_charger->charger,
362						 gpio_charger->gpiod);
363
364	charge_status_irq = gpio_charger_get_irq(dev, gpio_charger->charger,
365						 gpio_charger->charge_status);
366	gpio_charger->charge_status_irq = charge_status_irq;
367
368	platform_set_drvdata(pdev, gpio_charger);
369
370	ret = devm_device_init_wakeup(dev);
371	if (ret)
372		return dev_err_probe(dev, ret, "Failed to init wakeup\n");
373
374	return 0;
375}
376
377#ifdef CONFIG_PM_SLEEP
378static int gpio_charger_suspend(struct device *dev)
379{
380	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
381
382	if (device_may_wakeup(dev))
383		gpio_charger->wakeup_enabled =
384			!enable_irq_wake(gpio_charger->irq);
385
386	return 0;
387}
388
389static int gpio_charger_resume(struct device *dev)
390{
391	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
392
393	if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled)
394		disable_irq_wake(gpio_charger->irq);
395	power_supply_changed(gpio_charger->charger);
396
397	return 0;
398}
399#endif
400
401static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
402		gpio_charger_suspend, gpio_charger_resume);
403
404static const struct of_device_id gpio_charger_match[] = {
405	{ .compatible = "gpio-charger" },
406	{ }
407};
408MODULE_DEVICE_TABLE(of, gpio_charger_match);
409
410static struct platform_driver gpio_charger_driver = {
411	.probe = gpio_charger_probe,
412	.driver = {
413		.name = "gpio-charger",
414		.pm = &gpio_charger_pm_ops,
415		.of_match_table = gpio_charger_match,
416	},
417};
418
419module_platform_driver(gpio_charger_driver);
420
421MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
422MODULE_DESCRIPTION("Driver for chargers only communicating via GPIO(s)");
423MODULE_LICENSE("GPL");
424MODULE_ALIAS("platform:gpio-charger");