1 /* 2 * Copyright (c) 2016, Prodys S.L. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This adds support for sbs-charger compilant chips as defined here: 10 * http://sbs-forum.org/specs/sbc110.pdf 11 * 12 * Implemetation based on sbs-battery.c 13 */ 14 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/err.h> 19 #include <linux/power_supply.h> 20 #include <linux/i2c.h> 21 #include <linux/slab.h> 22 #include <linux/interrupt.h> 23 #include <linux/gpio.h> 24 #include <linux/regmap.h> 25 #include <linux/of_gpio.h> 26 #include <linux/bitops.h> 27 28 #define SBS_CHARGER_REG_SPEC_INFO 0x11 29 #define SBS_CHARGER_REG_STATUS 0x13 30 #define SBS_CHARGER_REG_ALARM_WARNING 0x16 31 32 #define SBS_CHARGER_STATUS_CHARGE_INHIBITED BIT(1) 33 #define SBS_CHARGER_STATUS_RES_COLD BIT(9) 34 #define SBS_CHARGER_STATUS_RES_HOT BIT(10) 35 #define SBS_CHARGER_STATUS_BATTERY_PRESENT BIT(14) 36 #define SBS_CHARGER_STATUS_AC_PRESENT BIT(15) 37 38 #define SBS_CHARGER_POLL_TIME 500 39 40 struct sbs_info { 41 struct i2c_client *client; 42 struct power_supply *power_supply; 43 struct regmap *regmap; 44 struct delayed_work work; 45 unsigned int last_state; 46 }; 47 48 static int sbs_get_property(struct power_supply *psy, 49 enum power_supply_property psp, 50 union power_supply_propval *val) 51 { 52 struct sbs_info *chip = power_supply_get_drvdata(psy); 53 unsigned int reg; 54 55 reg = chip->last_state; 56 57 switch (psp) { 58 case POWER_SUPPLY_PROP_PRESENT: 59 val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT); 60 break; 61 62 case POWER_SUPPLY_PROP_ONLINE: 63 val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT); 64 break; 65 66 case POWER_SUPPLY_PROP_STATUS: 67 val->intval = POWER_SUPPLY_STATUS_UNKNOWN; 68 69 if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT)) 70 val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING; 71 else if (reg & SBS_CHARGER_STATUS_AC_PRESENT && 72 !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED)) 73 val->intval = POWER_SUPPLY_STATUS_CHARGING; 74 else 75 val->intval = POWER_SUPPLY_STATUS_DISCHARGING; 76 77 break; 78 79 case POWER_SUPPLY_PROP_HEALTH: 80 if (reg & SBS_CHARGER_STATUS_RES_COLD) 81 val->intval = POWER_SUPPLY_HEALTH_COLD; 82 if (reg & SBS_CHARGER_STATUS_RES_HOT) 83 val->intval = POWER_SUPPLY_HEALTH_OVERHEAT; 84 else 85 val->intval = POWER_SUPPLY_HEALTH_GOOD; 86 87 break; 88 89 default: 90 return -EINVAL; 91 } 92 93 return 0; 94 } 95 96 static int sbs_check_state(struct sbs_info *chip) 97 { 98 unsigned int reg; 99 int ret; 100 101 ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, ®); 102 if (!ret && reg != chip->last_state) { 103 chip->last_state = reg; 104 power_supply_changed(chip->power_supply); 105 return 1; 106 } 107 108 return 0; 109 } 110 111 static void sbs_delayed_work(struct work_struct *work) 112 { 113 struct sbs_info *chip = container_of(work, struct sbs_info, work.work); 114 115 sbs_check_state(chip); 116 117 schedule_delayed_work(&chip->work, 118 msecs_to_jiffies(SBS_CHARGER_POLL_TIME)); 119 } 120 121 static irqreturn_t sbs_irq_thread(int irq, void *data) 122 { 123 struct sbs_info *chip = data; 124 int ret; 125 126 ret = sbs_check_state(chip); 127 128 return ret ? IRQ_HANDLED : IRQ_NONE; 129 } 130 131 static enum power_supply_property sbs_properties[] = { 132 POWER_SUPPLY_PROP_STATUS, 133 POWER_SUPPLY_PROP_PRESENT, 134 POWER_SUPPLY_PROP_ONLINE, 135 POWER_SUPPLY_PROP_HEALTH, 136 }; 137 138 static bool sbs_readable_reg(struct device *dev, unsigned int reg) 139 { 140 return reg >= SBS_CHARGER_REG_SPEC_INFO; 141 } 142 143 static bool sbs_volatile_reg(struct device *dev, unsigned int reg) 144 { 145 switch (reg) { 146 case SBS_CHARGER_REG_STATUS: 147 return true; 148 } 149 150 return false; 151 } 152 153 static const struct regmap_config sbs_regmap = { 154 .reg_bits = 8, 155 .val_bits = 16, 156 .max_register = SBS_CHARGER_REG_ALARM_WARNING, 157 .readable_reg = sbs_readable_reg, 158 .volatile_reg = sbs_volatile_reg, 159 .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */ 160 }; 161 162 static const struct power_supply_desc sbs_desc = { 163 .name = "sbs-charger", 164 .type = POWER_SUPPLY_TYPE_MAINS, 165 .properties = sbs_properties, 166 .num_properties = ARRAY_SIZE(sbs_properties), 167 .get_property = sbs_get_property, 168 }; 169 170 static int sbs_probe(struct i2c_client *client, 171 const struct i2c_device_id *id) 172 { 173 struct power_supply_config psy_cfg = {}; 174 struct sbs_info *chip; 175 int ret, val; 176 177 chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL); 178 if (!chip) 179 return -ENOMEM; 180 181 chip->client = client; 182 psy_cfg.of_node = client->dev.of_node; 183 psy_cfg.drv_data = chip; 184 185 i2c_set_clientdata(client, chip); 186 187 chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap); 188 if (IS_ERR(chip->regmap)) 189 return PTR_ERR(chip->regmap); 190 191 /* 192 * Before we register, we need to make sure we can actually talk 193 * to the battery. 194 */ 195 ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val); 196 if (ret) { 197 dev_err(&client->dev, "Failed to get device status\n"); 198 return ret; 199 } 200 chip->last_state = val; 201 202 chip->power_supply = devm_power_supply_register(&client->dev, &sbs_desc, 203 &psy_cfg); 204 if (IS_ERR(chip->power_supply)) { 205 dev_err(&client->dev, "Failed to register power supply\n"); 206 return PTR_ERR(chip->power_supply); 207 } 208 209 /* 210 * The sbs-charger spec doesn't impose the use of an interrupt. So in 211 * the case it wasn't provided we use polling in order get the charger's 212 * status. 213 */ 214 if (client->irq) { 215 ret = devm_request_threaded_irq(&client->dev, client->irq, 216 NULL, sbs_irq_thread, 217 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 218 dev_name(&client->dev), chip); 219 if (ret) { 220 dev_err(&client->dev, "Failed to request irq, %d\n", ret); 221 return ret; 222 } 223 } else { 224 INIT_DELAYED_WORK(&chip->work, sbs_delayed_work); 225 schedule_delayed_work(&chip->work, 226 msecs_to_jiffies(SBS_CHARGER_POLL_TIME)); 227 } 228 229 dev_info(&client->dev, 230 "%s: smart charger device registered\n", client->name); 231 232 return 0; 233 } 234 235 static int sbs_remove(struct i2c_client *client) 236 { 237 struct sbs_info *chip = i2c_get_clientdata(client); 238 239 cancel_delayed_work_sync(&chip->work); 240 241 return 0; 242 } 243 244 #ifdef CONFIG_OF 245 static const struct of_device_id sbs_dt_ids[] = { 246 { .compatible = "sbs,sbs-charger" }, 247 { }, 248 }; 249 MODULE_DEVICE_TABLE(of, sbs_dt_ids); 250 #endif 251 252 static const struct i2c_device_id sbs_id[] = { 253 { "sbs-charger", 0 }, 254 { } 255 }; 256 MODULE_DEVICE_TABLE(i2c, sbs_id); 257 258 static struct i2c_driver sbs_driver = { 259 .probe = sbs_probe, 260 .remove = sbs_remove, 261 .id_table = sbs_id, 262 .driver = { 263 .name = "sbs-charger", 264 .of_match_table = of_match_ptr(sbs_dt_ids), 265 }, 266 }; 267 module_i2c_driver(sbs_driver); 268 269 MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>"); 270 MODULE_DESCRIPTION("SBS smart charger driver"); 271 MODULE_LICENSE("GPL v2"); 272