1 /*
2 * Copyright (C) 2017, Topic Embedded Products
3 * Driver for LTC3651 charger IC.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 */
10
11 #include <linux/device.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/power_supply.h>
19 #include <linux/slab.h>
20 #include <linux/of.h>
21
22 struct ltc3651_charger {
23 struct power_supply *charger;
24 struct power_supply_desc charger_desc;
25 struct gpio_desc *acpr_gpio;
26 struct gpio_desc *fault_gpio;
27 struct gpio_desc *chrg_gpio;
28 };
29
ltc3651_charger_irq(int irq,void * devid)30 static irqreturn_t ltc3651_charger_irq(int irq, void *devid)
31 {
32 struct power_supply *charger = devid;
33
34 power_supply_changed(charger);
35
36 return IRQ_HANDLED;
37 }
38
psy_to_ltc3651_charger(struct power_supply * psy)39 static inline struct ltc3651_charger *psy_to_ltc3651_charger(
40 struct power_supply *psy)
41 {
42 return power_supply_get_drvdata(psy);
43 }
44
ltc3651_charger_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)45 static int ltc3651_charger_get_property(struct power_supply *psy,
46 enum power_supply_property psp, union power_supply_propval *val)
47 {
48 struct ltc3651_charger *ltc3651_charger = psy_to_ltc3651_charger(psy);
49
50 switch (psp) {
51 case POWER_SUPPLY_PROP_STATUS:
52 if (!ltc3651_charger->chrg_gpio) {
53 val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
54 break;
55 }
56 if (gpiod_get_value(ltc3651_charger->chrg_gpio))
57 val->intval = POWER_SUPPLY_STATUS_CHARGING;
58 else
59 val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
60 break;
61 case POWER_SUPPLY_PROP_ONLINE:
62 val->intval = gpiod_get_value(ltc3651_charger->acpr_gpio);
63 break;
64 case POWER_SUPPLY_PROP_HEALTH:
65 if (!ltc3651_charger->fault_gpio) {
66 val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
67 break;
68 }
69 if (!gpiod_get_value(ltc3651_charger->fault_gpio)) {
70 val->intval = POWER_SUPPLY_HEALTH_GOOD;
71 break;
72 }
73 /*
74 * If the fault pin is active, the chrg pin explains the type
75 * of failure.
76 */
77 if (!ltc3651_charger->chrg_gpio) {
78 val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
79 break;
80 }
81 val->intval = gpiod_get_value(ltc3651_charger->chrg_gpio) ?
82 POWER_SUPPLY_HEALTH_OVERHEAT :
83 POWER_SUPPLY_HEALTH_DEAD;
84 break;
85 default:
86 return -EINVAL;
87 }
88
89 return 0;
90 }
91
92 static enum power_supply_property ltc3651_charger_properties[] = {
93 POWER_SUPPLY_PROP_STATUS,
94 POWER_SUPPLY_PROP_ONLINE,
95 POWER_SUPPLY_PROP_HEALTH,
96 };
97
ltc3651_charger_probe(struct platform_device * pdev)98 static int ltc3651_charger_probe(struct platform_device *pdev)
99 {
100 struct power_supply_config psy_cfg = {};
101 struct ltc3651_charger *ltc3651_charger;
102 struct power_supply_desc *charger_desc;
103 int ret;
104
105 ltc3651_charger = devm_kzalloc(&pdev->dev, sizeof(*ltc3651_charger),
106 GFP_KERNEL);
107 if (!ltc3651_charger)
108 return -ENOMEM;
109
110 ltc3651_charger->acpr_gpio = devm_gpiod_get(&pdev->dev,
111 "lltc,acpr", GPIOD_IN);
112 if (IS_ERR(ltc3651_charger->acpr_gpio)) {
113 ret = PTR_ERR(ltc3651_charger->acpr_gpio);
114 dev_err(&pdev->dev, "Failed to acquire acpr GPIO: %d\n", ret);
115 return ret;
116 }
117 ltc3651_charger->fault_gpio = devm_gpiod_get_optional(&pdev->dev,
118 "lltc,fault", GPIOD_IN);
119 if (IS_ERR(ltc3651_charger->fault_gpio)) {
120 ret = PTR_ERR(ltc3651_charger->fault_gpio);
121 dev_err(&pdev->dev, "Failed to acquire fault GPIO: %d\n", ret);
122 return ret;
123 }
124 ltc3651_charger->chrg_gpio = devm_gpiod_get_optional(&pdev->dev,
125 "lltc,chrg", GPIOD_IN);
126 if (IS_ERR(ltc3651_charger->chrg_gpio)) {
127 ret = PTR_ERR(ltc3651_charger->chrg_gpio);
128 dev_err(&pdev->dev, "Failed to acquire chrg GPIO: %d\n", ret);
129 return ret;
130 }
131
132 charger_desc = <c3651_charger->charger_desc;
133 charger_desc->name = pdev->dev.of_node->name;
134 charger_desc->type = POWER_SUPPLY_TYPE_MAINS;
135 charger_desc->properties = ltc3651_charger_properties;
136 charger_desc->num_properties = ARRAY_SIZE(ltc3651_charger_properties);
137 charger_desc->get_property = ltc3651_charger_get_property;
138 psy_cfg.of_node = pdev->dev.of_node;
139 psy_cfg.drv_data = ltc3651_charger;
140
141 ltc3651_charger->charger = devm_power_supply_register(&pdev->dev,
142 charger_desc, &psy_cfg);
143 if (IS_ERR(ltc3651_charger->charger)) {
144 ret = PTR_ERR(ltc3651_charger->charger);
145 dev_err(&pdev->dev, "Failed to register power supply: %d\n",
146 ret);
147 return ret;
148 }
149
150 /*
151 * Acquire IRQs for the GPIO pins if possible. If the system does not
152 * support IRQs on these pins, userspace will have to poll the sysfs
153 * files manually.
154 */
155 if (ltc3651_charger->acpr_gpio) {
156 ret = gpiod_to_irq(ltc3651_charger->acpr_gpio);
157 if (ret >= 0)
158 ret = devm_request_any_context_irq(&pdev->dev, ret,
159 ltc3651_charger_irq,
160 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
161 dev_name(&pdev->dev), ltc3651_charger->charger);
162 if (ret < 0)
163 dev_warn(&pdev->dev, "Failed to request acpr irq\n");
164 }
165 if (ltc3651_charger->fault_gpio) {
166 ret = gpiod_to_irq(ltc3651_charger->fault_gpio);
167 if (ret >= 0)
168 ret = devm_request_any_context_irq(&pdev->dev, ret,
169 ltc3651_charger_irq,
170 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
171 dev_name(&pdev->dev), ltc3651_charger->charger);
172 if (ret < 0)
173 dev_warn(&pdev->dev, "Failed to request fault irq\n");
174 }
175 if (ltc3651_charger->chrg_gpio) {
176 ret = gpiod_to_irq(ltc3651_charger->chrg_gpio);
177 if (ret >= 0)
178 ret = devm_request_any_context_irq(&pdev->dev, ret,
179 ltc3651_charger_irq,
180 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
181 dev_name(&pdev->dev), ltc3651_charger->charger);
182 if (ret < 0)
183 dev_warn(&pdev->dev, "Failed to request chrg irq\n");
184 }
185
186 platform_set_drvdata(pdev, ltc3651_charger);
187
188 return 0;
189 }
190
191 static const struct of_device_id ltc3651_charger_match[] = {
192 { .compatible = "lltc,ltc3651-charger" },
193 { }
194 };
195 MODULE_DEVICE_TABLE(of, ltc3651_charger_match);
196
197 static struct platform_driver ltc3651_charger_driver = {
198 .probe = ltc3651_charger_probe,
199 .driver = {
200 .name = "ltc3651-charger",
201 .of_match_table = ltc3651_charger_match,
202 },
203 };
204
205 module_platform_driver(ltc3651_charger_driver);
206
207 MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
208 MODULE_DESCRIPTION("Driver for LTC3651 charger");
209 MODULE_LICENSE("GPL");
210 MODULE_ALIAS("platform:ltc3651-charger");
211