1 /* 2 * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de> 3 * Driver for chargers which report their online status through a GPIO pin 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License as published by the 7 * Free Software Foundation; either version 2 of the License, or (at your 8 * option) any later version. 9 * 10 * You should have received a copy of the GNU General Public License along 11 * with this program; if not, write to the Free Software Foundation, Inc., 12 * 675 Mass Ave, Cambridge, MA 02139, USA. 13 * 14 */ 15 16 #include <linux/device.h> 17 #include <linux/gpio.h> /* For legacy platform data */ 18 #include <linux/init.h> 19 #include <linux/interrupt.h> 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/platform_device.h> 23 #include <linux/power_supply.h> 24 #include <linux/slab.h> 25 #include <linux/of.h> 26 #include <linux/gpio/consumer.h> 27 28 #include <linux/power/gpio-charger.h> 29 30 struct gpio_charger { 31 const struct gpio_charger_platform_data *pdata; 32 unsigned int irq; 33 bool wakeup_enabled; 34 35 struct power_supply *charger; 36 struct power_supply_desc charger_desc; 37 struct gpio_desc *gpiod; 38 bool legacy_gpio_requested; 39 }; 40 41 static irqreturn_t gpio_charger_irq(int irq, void *devid) 42 { 43 struct power_supply *charger = devid; 44 45 power_supply_changed(charger); 46 47 return IRQ_HANDLED; 48 } 49 50 static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy) 51 { 52 return power_supply_get_drvdata(psy); 53 } 54 55 static int gpio_charger_get_property(struct power_supply *psy, 56 enum power_supply_property psp, union power_supply_propval *val) 57 { 58 struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy); 59 const struct gpio_charger_platform_data *pdata = gpio_charger->pdata; 60 61 switch (psp) { 62 case POWER_SUPPLY_PROP_ONLINE: 63 val->intval = gpiod_get_value_cansleep(gpio_charger->gpiod); 64 /* This xor is only ever used with legacy pdata GPIO */ 65 val->intval ^= pdata->gpio_active_low; 66 break; 67 default: 68 return -EINVAL; 69 } 70 71 return 0; 72 } 73 74 static enum power_supply_property gpio_charger_properties[] = { 75 POWER_SUPPLY_PROP_ONLINE, 76 }; 77 78 static 79 struct gpio_charger_platform_data *gpio_charger_parse_dt(struct device *dev) 80 { 81 struct device_node *np = dev->of_node; 82 struct gpio_charger_platform_data *pdata; 83 const char *chargetype; 84 int ret; 85 86 if (!np) 87 return ERR_PTR(-ENOENT); 88 89 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 90 if (!pdata) 91 return ERR_PTR(-ENOMEM); 92 93 pdata->name = np->name; 94 pdata->type = POWER_SUPPLY_TYPE_UNKNOWN; 95 ret = of_property_read_string(np, "charger-type", &chargetype); 96 if (ret >= 0) { 97 if (!strncmp("unknown", chargetype, 7)) 98 pdata->type = POWER_SUPPLY_TYPE_UNKNOWN; 99 else if (!strncmp("battery", chargetype, 7)) 100 pdata->type = POWER_SUPPLY_TYPE_BATTERY; 101 else if (!strncmp("ups", chargetype, 3)) 102 pdata->type = POWER_SUPPLY_TYPE_UPS; 103 else if (!strncmp("mains", chargetype, 5)) 104 pdata->type = POWER_SUPPLY_TYPE_MAINS; 105 else if (!strncmp("usb-sdp", chargetype, 7)) 106 pdata->type = POWER_SUPPLY_TYPE_USB; 107 else if (!strncmp("usb-dcp", chargetype, 7)) 108 pdata->type = POWER_SUPPLY_TYPE_USB_DCP; 109 else if (!strncmp("usb-cdp", chargetype, 7)) 110 pdata->type = POWER_SUPPLY_TYPE_USB_CDP; 111 else if (!strncmp("usb-aca", chargetype, 7)) 112 pdata->type = POWER_SUPPLY_TYPE_USB_ACA; 113 else 114 dev_warn(dev, "unknown charger type %s\n", chargetype); 115 } 116 117 return pdata; 118 } 119 120 static int gpio_charger_probe(struct platform_device *pdev) 121 { 122 const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data; 123 struct power_supply_config psy_cfg = {}; 124 struct gpio_charger *gpio_charger; 125 struct power_supply_desc *charger_desc; 126 int ret; 127 int irq; 128 129 if (!pdata) { 130 pdata = gpio_charger_parse_dt(&pdev->dev); 131 if (IS_ERR(pdata)) { 132 ret = PTR_ERR(pdata); 133 if (ret != -EPROBE_DEFER) 134 dev_err(&pdev->dev, "No platform data\n"); 135 return ret; 136 } 137 } 138 139 gpio_charger = devm_kzalloc(&pdev->dev, sizeof(*gpio_charger), 140 GFP_KERNEL); 141 if (!gpio_charger) { 142 dev_err(&pdev->dev, "Failed to alloc driver structure\n"); 143 return -ENOMEM; 144 } 145 146 /* 147 * This will fetch a GPIO descriptor from device tree, ACPI or 148 * boardfile descriptor tables. It's good to try this first. 149 */ 150 gpio_charger->gpiod = devm_gpiod_get(&pdev->dev, NULL, GPIOD_IN); 151 152 /* 153 * If this fails and we're not using device tree, try the 154 * legacy platform data method. 155 */ 156 if (IS_ERR(gpio_charger->gpiod) && !pdev->dev.of_node) { 157 /* Non-DT: use legacy GPIO numbers */ 158 if (!gpio_is_valid(pdata->gpio)) { 159 dev_err(&pdev->dev, "Invalid gpio pin in pdata\n"); 160 return -EINVAL; 161 } 162 ret = gpio_request(pdata->gpio, dev_name(&pdev->dev)); 163 if (ret) { 164 dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", 165 ret); 166 return ret; 167 } 168 gpio_charger->legacy_gpio_requested = true; 169 ret = gpio_direction_input(pdata->gpio); 170 if (ret) { 171 dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", 172 ret); 173 goto err_gpio_free; 174 } 175 /* Then convert this to gpiod for now */ 176 gpio_charger->gpiod = gpio_to_desc(pdata->gpio); 177 } else if (IS_ERR(gpio_charger->gpiod)) { 178 /* Just try again if this happens */ 179 if (PTR_ERR(gpio_charger->gpiod) == -EPROBE_DEFER) 180 return -EPROBE_DEFER; 181 dev_err(&pdev->dev, "error getting GPIO descriptor\n"); 182 return PTR_ERR(gpio_charger->gpiod); 183 } 184 185 charger_desc = &gpio_charger->charger_desc; 186 187 charger_desc->name = pdata->name ? pdata->name : "gpio-charger"; 188 charger_desc->type = pdata->type; 189 charger_desc->properties = gpio_charger_properties; 190 charger_desc->num_properties = ARRAY_SIZE(gpio_charger_properties); 191 charger_desc->get_property = gpio_charger_get_property; 192 193 psy_cfg.supplied_to = pdata->supplied_to; 194 psy_cfg.num_supplicants = pdata->num_supplicants; 195 psy_cfg.of_node = pdev->dev.of_node; 196 psy_cfg.drv_data = gpio_charger; 197 198 gpio_charger->pdata = pdata; 199 200 gpio_charger->charger = power_supply_register(&pdev->dev, 201 charger_desc, &psy_cfg); 202 if (IS_ERR(gpio_charger->charger)) { 203 ret = PTR_ERR(gpio_charger->charger); 204 dev_err(&pdev->dev, "Failed to register power supply: %d\n", 205 ret); 206 goto err_gpio_free; 207 } 208 209 irq = gpiod_to_irq(gpio_charger->gpiod); 210 if (irq > 0) { 211 ret = request_any_context_irq(irq, gpio_charger_irq, 212 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, 213 dev_name(&pdev->dev), gpio_charger->charger); 214 if (ret < 0) 215 dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret); 216 else 217 gpio_charger->irq = irq; 218 } 219 220 platform_set_drvdata(pdev, gpio_charger); 221 222 device_init_wakeup(&pdev->dev, 1); 223 224 return 0; 225 226 err_gpio_free: 227 if (gpio_charger->legacy_gpio_requested) 228 gpio_free(pdata->gpio); 229 return ret; 230 } 231 232 static int gpio_charger_remove(struct platform_device *pdev) 233 { 234 struct gpio_charger *gpio_charger = platform_get_drvdata(pdev); 235 236 if (gpio_charger->irq) 237 free_irq(gpio_charger->irq, gpio_charger->charger); 238 239 power_supply_unregister(gpio_charger->charger); 240 241 if (gpio_charger->legacy_gpio_requested) 242 gpio_free(gpio_charger->pdata->gpio); 243 244 return 0; 245 } 246 247 #ifdef CONFIG_PM_SLEEP 248 static int gpio_charger_suspend(struct device *dev) 249 { 250 struct gpio_charger *gpio_charger = dev_get_drvdata(dev); 251 252 if (device_may_wakeup(dev)) 253 gpio_charger->wakeup_enabled = 254 !enable_irq_wake(gpio_charger->irq); 255 256 return 0; 257 } 258 259 static int gpio_charger_resume(struct device *dev) 260 { 261 struct platform_device *pdev = to_platform_device(dev); 262 struct gpio_charger *gpio_charger = platform_get_drvdata(pdev); 263 264 if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled) 265 disable_irq_wake(gpio_charger->irq); 266 power_supply_changed(gpio_charger->charger); 267 268 return 0; 269 } 270 #endif 271 272 static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops, 273 gpio_charger_suspend, gpio_charger_resume); 274 275 static const struct of_device_id gpio_charger_match[] = { 276 { .compatible = "gpio-charger" }, 277 { } 278 }; 279 MODULE_DEVICE_TABLE(of, gpio_charger_match); 280 281 static struct platform_driver gpio_charger_driver = { 282 .probe = gpio_charger_probe, 283 .remove = gpio_charger_remove, 284 .driver = { 285 .name = "gpio-charger", 286 .pm = &gpio_charger_pm_ops, 287 .of_match_table = gpio_charger_match, 288 }, 289 }; 290 291 module_platform_driver(gpio_charger_driver); 292 293 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 294 MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO"); 295 MODULE_LICENSE("GPL"); 296 MODULE_ALIAS("platform:gpio-charger"); 297