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