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(0)
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
36struct 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
44static 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
92static 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, &reg);
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
107static 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
117static 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
127static 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
134static bool sbs_readable_reg(struct device *dev, unsigned int reg)
135{
136	return reg >= SBS_CHARGER_REG_SPEC_INFO;
137}
138
139static 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
149static 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
158static 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
166static 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
231static 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
241static const struct of_device_id sbs_dt_ids[] = {
242	{ .compatible = "sbs,sbs-charger" },
243	{ },
244};
245MODULE_DEVICE_TABLE(of, sbs_dt_ids);
246#endif
247
248static const struct i2c_device_id sbs_id[] = {
249	{ "sbs-charger", 0 },
250	{ }
251};
252MODULE_DEVICE_TABLE(i2c, sbs_id);
253
254static 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};
263module_i2c_driver(sbs_driver);
264
265MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
266MODULE_DESCRIPTION("SBS smart charger driver");
267MODULE_LICENSE("GPL v2");
268