1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2016, Prodys S.L.
4 *
5 * This adds support for sbs-charger compilant chips as defined here:
6 * http://sbs-forum.org/specs/sbc110.pdf
7 *
8 * Implemetation based on sbs-battery.c
9 */
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/err.h>
15 #include <linux/power_supply.h>
16 #include <linux/i2c.h>
17 #include <linux/slab.h>
18 #include <linux/interrupt.h>
19 #include <linux/gpio.h>
20 #include <linux/regmap.h>
21 #include <linux/of_gpio.h>
22 #include <linux/bitops.h>
23
24 #define SBS_CHARGER_REG_SPEC_INFO 0x11
25 #define SBS_CHARGER_REG_STATUS 0x13
26 #define SBS_CHARGER_REG_ALARM_WARNING 0x16
27
28 #define SBS_CHARGER_STATUS_CHARGE_INHIBITED BIT(1)
29 #define SBS_CHARGER_STATUS_RES_COLD BIT(9)
30 #define SBS_CHARGER_STATUS_RES_HOT BIT(10)
31 #define SBS_CHARGER_STATUS_BATTERY_PRESENT BIT(14)
32 #define SBS_CHARGER_STATUS_AC_PRESENT BIT(15)
33
34 #define SBS_CHARGER_POLL_TIME 500
35
36 struct sbs_info {
37 struct i2c_client *client;
38 struct power_supply *power_supply;
39 struct regmap *regmap;
40 struct delayed_work work;
41 unsigned int last_state;
42 };
43
sbs_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)44 static int sbs_get_property(struct power_supply *psy,
45 enum power_supply_property psp,
46 union power_supply_propval *val)
47 {
48 struct sbs_info *chip = power_supply_get_drvdata(psy);
49 unsigned int reg;
50
51 reg = chip->last_state;
52
53 switch (psp) {
54 case POWER_SUPPLY_PROP_PRESENT:
55 val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
56 break;
57
58 case POWER_SUPPLY_PROP_ONLINE:
59 val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
60 break;
61
62 case POWER_SUPPLY_PROP_STATUS:
63 val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
64
65 if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
66 val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
67 else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
68 !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
69 val->intval = POWER_SUPPLY_STATUS_CHARGING;
70 else
71 val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
72
73 break;
74
75 case POWER_SUPPLY_PROP_HEALTH:
76 if (reg & SBS_CHARGER_STATUS_RES_COLD)
77 val->intval = POWER_SUPPLY_HEALTH_COLD;
78 if (reg & SBS_CHARGER_STATUS_RES_HOT)
79 val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
80 else
81 val->intval = POWER_SUPPLY_HEALTH_GOOD;
82
83 break;
84
85 default:
86 return -EINVAL;
87 }
88
89 return 0;
90 }
91
sbs_check_state(struct sbs_info * chip)92 static int sbs_check_state(struct sbs_info *chip)
93 {
94 unsigned int reg;
95 int ret;
96
97 ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, ®);
98 if (!ret && reg != chip->last_state) {
99 chip->last_state = reg;
100 power_supply_changed(chip->power_supply);
101 return 1;
102 }
103
104 return 0;
105 }
106
sbs_delayed_work(struct work_struct * work)107 static void sbs_delayed_work(struct work_struct *work)
108 {
109 struct sbs_info *chip = container_of(work, struct sbs_info, work.work);
110
111 sbs_check_state(chip);
112
113 schedule_delayed_work(&chip->work,
114 msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
115 }
116
sbs_irq_thread(int irq,void * data)117 static irqreturn_t sbs_irq_thread(int irq, void *data)
118 {
119 struct sbs_info *chip = data;
120 int ret;
121
122 ret = sbs_check_state(chip);
123
124 return ret ? IRQ_HANDLED : IRQ_NONE;
125 }
126
127 static enum power_supply_property sbs_properties[] = {
128 POWER_SUPPLY_PROP_STATUS,
129 POWER_SUPPLY_PROP_PRESENT,
130 POWER_SUPPLY_PROP_ONLINE,
131 POWER_SUPPLY_PROP_HEALTH,
132 };
133
sbs_readable_reg(struct device * dev,unsigned int reg)134 static bool sbs_readable_reg(struct device *dev, unsigned int reg)
135 {
136 return reg >= SBS_CHARGER_REG_SPEC_INFO;
137 }
138
sbs_volatile_reg(struct device * dev,unsigned int reg)139 static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
140 {
141 switch (reg) {
142 case SBS_CHARGER_REG_STATUS:
143 return true;
144 }
145
146 return false;
147 }
148
149 static const struct regmap_config sbs_regmap = {
150 .reg_bits = 8,
151 .val_bits = 16,
152 .max_register = SBS_CHARGER_REG_ALARM_WARNING,
153 .readable_reg = sbs_readable_reg,
154 .volatile_reg = sbs_volatile_reg,
155 .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
156 };
157
158 static const struct power_supply_desc sbs_desc = {
159 .name = "sbs-charger",
160 .type = POWER_SUPPLY_TYPE_MAINS,
161 .properties = sbs_properties,
162 .num_properties = ARRAY_SIZE(sbs_properties),
163 .get_property = sbs_get_property,
164 };
165
sbs_probe(struct i2c_client * client,const struct i2c_device_id * id)166 static int sbs_probe(struct i2c_client *client,
167 const struct i2c_device_id *id)
168 {
169 struct power_supply_config psy_cfg = {};
170 struct sbs_info *chip;
171 int ret, val;
172
173 chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
174 if (!chip)
175 return -ENOMEM;
176
177 chip->client = client;
178 psy_cfg.of_node = client->dev.of_node;
179 psy_cfg.drv_data = chip;
180
181 i2c_set_clientdata(client, chip);
182
183 chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap);
184 if (IS_ERR(chip->regmap))
185 return PTR_ERR(chip->regmap);
186
187 /*
188 * Before we register, we need to make sure we can actually talk
189 * to the battery.
190 */
191 ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val);
192 if (ret) {
193 dev_err(&client->dev, "Failed to get device status\n");
194 return ret;
195 }
196 chip->last_state = val;
197
198 chip->power_supply = devm_power_supply_register(&client->dev, &sbs_desc,
199 &psy_cfg);
200 if (IS_ERR(chip->power_supply)) {
201 dev_err(&client->dev, "Failed to register power supply\n");
202 return PTR_ERR(chip->power_supply);
203 }
204
205 /*
206 * The sbs-charger spec doesn't impose the use of an interrupt. So in
207 * the case it wasn't provided we use polling in order get the charger's
208 * status.
209 */
210 if (client->irq) {
211 ret = devm_request_threaded_irq(&client->dev, client->irq,
212 NULL, sbs_irq_thread,
213 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
214 dev_name(&client->dev), chip);
215 if (ret) {
216 dev_err(&client->dev, "Failed to request irq, %d\n", ret);
217 return ret;
218 }
219 } else {
220 INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
221 schedule_delayed_work(&chip->work,
222 msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
223 }
224
225 dev_info(&client->dev,
226 "%s: smart charger device registered\n", client->name);
227
228 return 0;
229 }
230
sbs_remove(struct i2c_client * client)231 static int sbs_remove(struct i2c_client *client)
232 {
233 struct sbs_info *chip = i2c_get_clientdata(client);
234
235 cancel_delayed_work_sync(&chip->work);
236
237 return 0;
238 }
239
240 #ifdef CONFIG_OF
241 static const struct of_device_id sbs_dt_ids[] = {
242 { .compatible = "sbs,sbs-charger" },
243 { },
244 };
245 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
246 #endif
247
248 static const struct i2c_device_id sbs_id[] = {
249 { "sbs-charger", 0 },
250 { }
251 };
252 MODULE_DEVICE_TABLE(i2c, sbs_id);
253
254 static struct i2c_driver sbs_driver = {
255 .probe = sbs_probe,
256 .remove = sbs_remove,
257 .id_table = sbs_id,
258 .driver = {
259 .name = "sbs-charger",
260 .of_match_table = of_match_ptr(sbs_dt_ids),
261 },
262 };
263 module_i2c_driver(sbs_driver);
264
265 MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
266 MODULE_DESCRIPTION("SBS smart charger driver");
267 MODULE_LICENSE("GPL v2");
268
