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