1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * max8903_charger.c - Maxim 8903 USB/Adapter Charger Driver
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 */
8
9 #include <linux/gpio/consumer.h>
10 #include <linux/interrupt.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/slab.h>
14 #include <linux/power_supply.h>
15 #include <linux/platform_device.h>
16
17 struct max8903_data {
18 struct device *dev;
19 struct power_supply *psy;
20 struct power_supply_desc psy_desc;
21 /*
22 * GPIOs
23 * chg, flt, dcm and usus are optional.
24 * dok or uok must be present.
25 * If dok is present, cen must be present.
26 */
27 struct gpio_desc *cen; /* Charger Enable input */
28 struct gpio_desc *dok; /* DC (Adapter) Power OK output */
29 struct gpio_desc *uok; /* USB Power OK output */
30 struct gpio_desc *chg; /* Charger status output */
31 struct gpio_desc *flt; /* Fault output */
32 struct gpio_desc *dcm; /* Current-Limit Mode input (1: DC, 2: USB) */
33 struct gpio_desc *usus; /* USB Suspend Input (1: suspended) */
34 bool fault;
35 bool usb_in;
36 bool ta_in;
37 };
38
39 static enum power_supply_property max8903_charger_props[] = {
40 POWER_SUPPLY_PROP_STATUS, /* Charger status output */
41 POWER_SUPPLY_PROP_ONLINE, /* External power source */
42 POWER_SUPPLY_PROP_HEALTH, /* Fault or OK */
43 };
44
max8903_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)45 static int max8903_get_property(struct power_supply *psy,
46 enum power_supply_property psp,
47 union power_supply_propval *val)
48 {
49 struct max8903_data *data = power_supply_get_drvdata(psy);
50
51 switch (psp) {
52 case POWER_SUPPLY_PROP_STATUS:
53 val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
54 if (data->chg) {
55 if (gpiod_get_value(data->chg))
56 /* CHG asserted */
57 val->intval = POWER_SUPPLY_STATUS_CHARGING;
58 else if (data->usb_in || data->ta_in)
59 val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
60 else
61 val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
62 }
63 break;
64 case POWER_SUPPLY_PROP_ONLINE:
65 val->intval = 0;
66 if (data->usb_in || data->ta_in)
67 val->intval = 1;
68 break;
69 case POWER_SUPPLY_PROP_HEALTH:
70 val->intval = POWER_SUPPLY_HEALTH_GOOD;
71 if (data->fault)
72 val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
73 break;
74 default:
75 return -EINVAL;
76 }
77
78 return 0;
79 }
80
max8903_dcin(int irq,void * _data)81 static irqreturn_t max8903_dcin(int irq, void *_data)
82 {
83 struct max8903_data *data = _data;
84 bool ta_in;
85 enum power_supply_type old_type;
86
87 /*
88 * This means the line is asserted.
89 *
90 * The signal is active low, but the inversion is handled in the GPIO
91 * library as the line should be flagged GPIO_ACTIVE_LOW in the device
92 * tree.
93 */
94 ta_in = gpiod_get_value(data->dok);
95
96 if (ta_in == data->ta_in)
97 return IRQ_HANDLED;
98
99 data->ta_in = ta_in;
100
101 /* Set Current-Limit-Mode 1:DC 0:USB */
102 if (data->dcm)
103 gpiod_set_value(data->dcm, ta_in);
104
105 /* Charger Enable / Disable */
106 if (data->cen) {
107 int val;
108
109 if (ta_in)
110 /* Certainly enable if DOK is asserted */
111 val = 1;
112 else if (data->usb_in)
113 /* Enable if the USB charger is enabled */
114 val = 1;
115 else
116 /* Else default-disable */
117 val = 0;
118
119 gpiod_set_value(data->cen, val);
120 }
121
122 dev_dbg(data->dev, "TA(DC-IN) Charger %s.\n", ta_in ?
123 "Connected" : "Disconnected");
124
125 old_type = data->psy_desc.type;
126
127 if (data->ta_in)
128 data->psy_desc.type = POWER_SUPPLY_TYPE_MAINS;
129 else if (data->usb_in)
130 data->psy_desc.type = POWER_SUPPLY_TYPE_USB;
131 else
132 data->psy_desc.type = POWER_SUPPLY_TYPE_BATTERY;
133
134 if (old_type != data->psy_desc.type)
135 power_supply_changed(data->psy);
136
137 return IRQ_HANDLED;
138 }
139
max8903_usbin(int irq,void * _data)140 static irqreturn_t max8903_usbin(int irq, void *_data)
141 {
142 struct max8903_data *data = _data;
143 bool usb_in;
144 enum power_supply_type old_type;
145
146 /*
147 * This means the line is asserted.
148 *
149 * The signal is active low, but the inversion is handled in the GPIO
150 * library as the line should be flagged GPIO_ACTIVE_LOW in the device
151 * tree.
152 */
153 usb_in = gpiod_get_value(data->uok);
154
155 if (usb_in == data->usb_in)
156 return IRQ_HANDLED;
157
158 data->usb_in = usb_in;
159
160 /* Do not touch Current-Limit-Mode */
161
162 /* Charger Enable / Disable */
163 if (data->cen) {
164 int val;
165
166 if (usb_in)
167 /* Certainly enable if UOK is asserted */
168 val = 1;
169 else if (data->ta_in)
170 /* Enable if the DC charger is enabled */
171 val = 1;
172 else
173 /* Else default-disable */
174 val = 0;
175
176 gpiod_set_value(data->cen, val);
177 }
178
179 dev_dbg(data->dev, "USB Charger %s.\n", usb_in ?
180 "Connected" : "Disconnected");
181
182 old_type = data->psy_desc.type;
183
184 if (data->ta_in)
185 data->psy_desc.type = POWER_SUPPLY_TYPE_MAINS;
186 else if (data->usb_in)
187 data->psy_desc.type = POWER_SUPPLY_TYPE_USB;
188 else
189 data->psy_desc.type = POWER_SUPPLY_TYPE_BATTERY;
190
191 if (old_type != data->psy_desc.type)
192 power_supply_changed(data->psy);
193
194 return IRQ_HANDLED;
195 }
196
max8903_fault(int irq,void * _data)197 static irqreturn_t max8903_fault(int irq, void *_data)
198 {
199 struct max8903_data *data = _data;
200 bool fault;
201
202 /*
203 * This means the line is asserted.
204 *
205 * The signal is active low, but the inversion is handled in the GPIO
206 * library as the line should be flagged GPIO_ACTIVE_LOW in the device
207 * tree.
208 */
209 fault = gpiod_get_value(data->flt);
210
211 if (fault == data->fault)
212 return IRQ_HANDLED;
213
214 data->fault = fault;
215
216 if (fault)
217 dev_err(data->dev, "Charger suffers a fault and stops.\n");
218 else
219 dev_err(data->dev, "Charger recovered from a fault.\n");
220
221 return IRQ_HANDLED;
222 }
223
max8903_setup_gpios(struct platform_device * pdev)224 static int max8903_setup_gpios(struct platform_device *pdev)
225 {
226 struct max8903_data *data = platform_get_drvdata(pdev);
227 struct device *dev = &pdev->dev;
228 bool ta_in = false;
229 bool usb_in = false;
230 enum gpiod_flags flags;
231
232 data->dok = devm_gpiod_get_optional(dev, "dok", GPIOD_IN);
233 if (IS_ERR(data->dok))
234 return dev_err_probe(dev, PTR_ERR(data->dok),
235 "failed to get DOK GPIO");
236 if (data->dok) {
237 gpiod_set_consumer_name(data->dok, data->psy_desc.name);
238 /*
239 * The DC OK is pulled up to 1 and goes low when a charger
240 * is plugged in (active low) but in the device tree the
241 * line is marked as GPIO_ACTIVE_LOW so we get a 1 (asserted)
242 * here if the DC charger is plugged in.
243 */
244 ta_in = gpiod_get_value(data->dok);
245 }
246
247 data->uok = devm_gpiod_get_optional(dev, "uok", GPIOD_IN);
248 if (IS_ERR(data->uok))
249 return dev_err_probe(dev, PTR_ERR(data->uok),
250 "failed to get UOK GPIO");
251 if (data->uok) {
252 gpiod_set_consumer_name(data->uok, data->psy_desc.name);
253 /*
254 * The USB OK is pulled up to 1 and goes low when a USB charger
255 * is plugged in (active low) but in the device tree the
256 * line is marked as GPIO_ACTIVE_LOW so we get a 1 (asserted)
257 * here if the USB charger is plugged in.
258 */
259 usb_in = gpiod_get_value(data->uok);
260 }
261
262 /* Either DC OK or USB OK must be provided */
263 if (!data->dok && !data->uok) {
264 dev_err(dev, "no valid power source\n");
265 return -EINVAL;
266 }
267
268 /*
269 * If either charger is already connected at this point,
270 * assert the CEN line and enable charging from the start.
271 *
272 * The line is active low but also marked with GPIO_ACTIVE_LOW
273 * in the device tree, so when we assert the line with
274 * GPIOD_OUT_HIGH the line will be driven low.
275 */
276 flags = (ta_in || usb_in) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
277 /*
278 * If DC OK is provided, Charger Enable CEN is compulsory
279 * so this is not optional here.
280 */
281 data->cen = devm_gpiod_get(dev, "cen", flags);
282 if (IS_ERR(data->cen))
283 return dev_err_probe(dev, PTR_ERR(data->cen),
284 "failed to get CEN GPIO");
285 gpiod_set_consumer_name(data->cen, data->psy_desc.name);
286
287 /*
288 * If the DC charger is connected, then select it.
289 *
290 * The DCM line should be marked GPIO_ACTIVE_HIGH in the
291 * device tree. Driving it high will enable the DC charger
292 * input over the USB charger input.
293 */
294 flags = ta_in ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
295 data->dcm = devm_gpiod_get_optional(dev, "dcm", flags);
296 if (IS_ERR(data->dcm))
297 return dev_err_probe(dev, PTR_ERR(data->dcm),
298 "failed to get DCM GPIO");
299 gpiod_set_consumer_name(data->dcm, data->psy_desc.name);
300
301 data->chg = devm_gpiod_get_optional(dev, "chg", GPIOD_IN);
302 if (IS_ERR(data->chg))
303 return dev_err_probe(dev, PTR_ERR(data->chg),
304 "failed to get CHG GPIO");
305 gpiod_set_consumer_name(data->chg, data->psy_desc.name);
306
307 data->flt = devm_gpiod_get_optional(dev, "flt", GPIOD_IN);
308 if (IS_ERR(data->flt))
309 return dev_err_probe(dev, PTR_ERR(data->flt),
310 "failed to get FLT GPIO");
311 gpiod_set_consumer_name(data->flt, data->psy_desc.name);
312
313 data->usus = devm_gpiod_get_optional(dev, "usus", GPIOD_IN);
314 if (IS_ERR(data->usus))
315 return dev_err_probe(dev, PTR_ERR(data->usus),
316 "failed to get USUS GPIO");
317 gpiod_set_consumer_name(data->usus, data->psy_desc.name);
318
319 data->fault = false;
320 data->ta_in = ta_in;
321 data->usb_in = usb_in;
322
323 return 0;
324 }
325
max8903_probe(struct platform_device * pdev)326 static int max8903_probe(struct platform_device *pdev)
327 {
328 struct max8903_data *data;
329 struct device *dev = &pdev->dev;
330 struct power_supply_config psy_cfg = {};
331 int ret = 0;
332
333 data = devm_kzalloc(dev, sizeof(struct max8903_data), GFP_KERNEL);
334 if (!data)
335 return -ENOMEM;
336
337 data->dev = dev;
338 platform_set_drvdata(pdev, data);
339
340 ret = max8903_setup_gpios(pdev);
341 if (ret)
342 return ret;
343
344 data->psy_desc.name = "max8903_charger";
345 data->psy_desc.type = (data->ta_in) ? POWER_SUPPLY_TYPE_MAINS :
346 ((data->usb_in) ? POWER_SUPPLY_TYPE_USB :
347 POWER_SUPPLY_TYPE_BATTERY);
348 data->psy_desc.get_property = max8903_get_property;
349 data->psy_desc.properties = max8903_charger_props;
350 data->psy_desc.num_properties = ARRAY_SIZE(max8903_charger_props);
351
352 psy_cfg.of_node = dev->of_node;
353 psy_cfg.drv_data = data;
354
355 data->psy = devm_power_supply_register(dev, &data->psy_desc, &psy_cfg);
356 if (IS_ERR(data->psy)) {
357 dev_err(dev, "failed: power supply register.\n");
358 return PTR_ERR(data->psy);
359 }
360
361 if (data->dok) {
362 ret = devm_request_threaded_irq(dev, gpiod_to_irq(data->dok),
363 NULL, max8903_dcin,
364 IRQF_TRIGGER_FALLING |
365 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
366 "MAX8903 DC IN", data);
367 if (ret) {
368 dev_err(dev, "Cannot request irq %d for DC (%d)\n",
369 gpiod_to_irq(data->dok), ret);
370 return ret;
371 }
372 }
373
374 if (data->uok) {
375 ret = devm_request_threaded_irq(dev, gpiod_to_irq(data->uok),
376 NULL, max8903_usbin,
377 IRQF_TRIGGER_FALLING |
378 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
379 "MAX8903 USB IN", data);
380 if (ret) {
381 dev_err(dev, "Cannot request irq %d for USB (%d)\n",
382 gpiod_to_irq(data->uok), ret);
383 return ret;
384 }
385 }
386
387 if (data->flt) {
388 ret = devm_request_threaded_irq(dev, gpiod_to_irq(data->flt),
389 NULL, max8903_fault,
390 IRQF_TRIGGER_FALLING |
391 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
392 "MAX8903 Fault", data);
393 if (ret) {
394 dev_err(dev, "Cannot request irq %d for Fault (%d)\n",
395 gpiod_to_irq(data->flt), ret);
396 return ret;
397 }
398 }
399
400 return 0;
401 }
402
403 static const struct of_device_id max8903_match_ids[] = {
404 { .compatible = "maxim,max8903", },
405 { /* sentinel */ }
406 };
407 MODULE_DEVICE_TABLE(of, max8903_match_ids);
408
409 static struct platform_driver max8903_driver = {
410 .probe = max8903_probe,
411 .driver = {
412 .name = "max8903-charger",
413 .of_match_table = max8903_match_ids
414 },
415 };
416
417 module_platform_driver(max8903_driver);
418
419 MODULE_LICENSE("GPL");
420 MODULE_DESCRIPTION("MAX8903 Charger Driver");
421 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
422 MODULE_ALIAS("platform:max8903-charger");
423