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
