1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Charging control driver for the Wilco EC
4 *
5 * Copyright 2019 Google LLC
6 *
7 * See Documentation/ABI/testing/sysfs-class-power and
8 * Documentation/ABI/testing/sysfs-class-power-wilco for userspace interface
9 * and other info.
10 */
11
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/platform_data/wilco-ec.h>
15#include <linux/power_supply.h>
16
17#define DRV_NAME "wilco-charger"
18
19/* Property IDs and related EC constants */
20#define PID_CHARGE_MODE		0x0710
21#define PID_CHARGE_LOWER_LIMIT	0x0711
22#define PID_CHARGE_UPPER_LIMIT	0x0712
23
24enum charge_mode {
25	CHARGE_MODE_STD = 1,	/* Used for Standard */
26	CHARGE_MODE_EXP = 2,	/* Express Charge, used for Fast */
27	CHARGE_MODE_AC = 3,	/* Mostly AC use, used for Trickle */
28	CHARGE_MODE_AUTO = 4,	/* Used for Adaptive */
29	CHARGE_MODE_CUSTOM = 5,	/* Used for Custom */
30	CHARGE_MODE_LONGLIFE = 6, /* Used for Long Life */
31};
32
33#define CHARGE_LOWER_LIMIT_MIN	50
34#define CHARGE_LOWER_LIMIT_MAX	95
35#define CHARGE_UPPER_LIMIT_MIN	55
36#define CHARGE_UPPER_LIMIT_MAX	100
37
38/* Convert from POWER_SUPPLY_PROP_CHARGE_TYPE value to the EC's charge mode */
39static int psp_val_to_charge_mode(int psp_val)
40{
41	switch (psp_val) {
42	case POWER_SUPPLY_CHARGE_TYPE_TRICKLE:
43		return CHARGE_MODE_AC;
44	case POWER_SUPPLY_CHARGE_TYPE_FAST:
45		return CHARGE_MODE_EXP;
46	case POWER_SUPPLY_CHARGE_TYPE_STANDARD:
47		return CHARGE_MODE_STD;
48	case POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE:
49		return CHARGE_MODE_AUTO;
50	case POWER_SUPPLY_CHARGE_TYPE_CUSTOM:
51		return CHARGE_MODE_CUSTOM;
52	case POWER_SUPPLY_CHARGE_TYPE_LONGLIFE:
53		return CHARGE_MODE_LONGLIFE;
54	default:
55		return -EINVAL;
56	}
57}
58
59/* Convert from EC's charge mode to POWER_SUPPLY_PROP_CHARGE_TYPE value */
60static int charge_mode_to_psp_val(enum charge_mode mode)
61{
62	switch (mode) {
63	case CHARGE_MODE_AC:
64		return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
65	case CHARGE_MODE_EXP:
66		return POWER_SUPPLY_CHARGE_TYPE_FAST;
67	case CHARGE_MODE_STD:
68		return POWER_SUPPLY_CHARGE_TYPE_STANDARD;
69	case CHARGE_MODE_AUTO:
70		return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
71	case CHARGE_MODE_CUSTOM:
72		return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
73	case CHARGE_MODE_LONGLIFE:
74		return POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
75	default:
76		return -EINVAL;
77	}
78}
79
80static enum power_supply_property wilco_charge_props[] = {
81	POWER_SUPPLY_PROP_CHARGE_TYPE,
82	POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
83	POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
84};
85
86static int wilco_charge_get_property(struct power_supply *psy,
87				     enum power_supply_property psp,
88				     union power_supply_propval *val)
89{
90	struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
91	u32 property_id;
92	int ret;
93	u8 raw;
94
95	switch (psp) {
96	case POWER_SUPPLY_PROP_CHARGE_TYPE:
97		property_id = PID_CHARGE_MODE;
98		break;
99	case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
100		property_id = PID_CHARGE_LOWER_LIMIT;
101		break;
102	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
103		property_id = PID_CHARGE_UPPER_LIMIT;
104		break;
105	default:
106		return -EINVAL;
107	}
108
109	ret = wilco_ec_get_byte_property(ec, property_id, &raw);
110	if (ret < 0)
111		return ret;
112	if (property_id == PID_CHARGE_MODE) {
113		ret = charge_mode_to_psp_val(raw);
114		if (ret < 0)
115			return -EBADMSG;
116		raw = ret;
117	}
118	val->intval = raw;
119
120	return 0;
121}
122
123static int wilco_charge_set_property(struct power_supply *psy,
124				     enum power_supply_property psp,
125				     const union power_supply_propval *val)
126{
127	struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
128	int mode;
129
130	switch (psp) {
131	case POWER_SUPPLY_PROP_CHARGE_TYPE:
132		mode = psp_val_to_charge_mode(val->intval);
133		if (mode < 0)
134			return -EINVAL;
135		return wilco_ec_set_byte_property(ec, PID_CHARGE_MODE, mode);
136	case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
137		if (val->intval < CHARGE_LOWER_LIMIT_MIN ||
138		    val->intval > CHARGE_LOWER_LIMIT_MAX)
139			return -EINVAL;
140		return wilco_ec_set_byte_property(ec, PID_CHARGE_LOWER_LIMIT,
141						  val->intval);
142	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
143		if (val->intval < CHARGE_UPPER_LIMIT_MIN ||
144		    val->intval > CHARGE_UPPER_LIMIT_MAX)
145			return -EINVAL;
146		return wilco_ec_set_byte_property(ec, PID_CHARGE_UPPER_LIMIT,
147						  val->intval);
148	default:
149		return -EINVAL;
150	}
151}
152
153static int wilco_charge_property_is_writeable(struct power_supply *psy,
154					      enum power_supply_property psp)
155{
156	return 1;
157}
158
159static const struct power_supply_desc wilco_ps_desc = {
160	.properties		= wilco_charge_props,
161	.num_properties		= ARRAY_SIZE(wilco_charge_props),
162	.get_property		= wilco_charge_get_property,
163	.set_property		= wilco_charge_set_property,
164	.property_is_writeable	= wilco_charge_property_is_writeable,
165	.name			= DRV_NAME,
166	.type			= POWER_SUPPLY_TYPE_MAINS,
167};
168
169static int wilco_charge_probe(struct platform_device *pdev)
170{
171	struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
172	struct power_supply_config psy_cfg = {};
173	struct power_supply *psy;
174
175	psy_cfg.drv_data = ec;
176	psy = devm_power_supply_register(&pdev->dev, &wilco_ps_desc, &psy_cfg);
177
178	return PTR_ERR_OR_ZERO(psy);
179}
180
181static struct platform_driver wilco_charge_driver = {
182	.probe	= wilco_charge_probe,
183	.driver = {
184		.name = DRV_NAME,
185	}
186};
187module_platform_driver(wilco_charge_driver);
188
189MODULE_ALIAS("platform:" DRV_NAME);
190MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
191MODULE_LICENSE("GPL v2");
192MODULE_DESCRIPTION("Wilco EC charge control driver");
193