drivers/power/supply/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
  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
  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
  51 static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
  52 {
  53         return power_supply_get_drvdata(psy);
  54 }
  55
  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
  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
 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
 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
 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
 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
 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
 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
 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
 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");