1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Driver for Analog Devices (Linear Technology) LT3651 charger IC.
4  *  Copyright (C) 2017, Topic Embedded Products
5  */
6 
7 #include <linux/device.h>
8 #include <linux/gpio/consumer.h>
9 #include <linux/init.h>
10 #include <linux/interrupt.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/power_supply.h>
15 #include <linux/slab.h>
16 #include <linux/of.h>
17 
18 struct lt3651_charger {
19 	struct power_supply *charger;
20 	struct power_supply_desc charger_desc;
21 	struct gpio_desc *acpr_gpio;
22 	struct gpio_desc *fault_gpio;
23 	struct gpio_desc *chrg_gpio;
24 };
25 
lt3651_charger_irq(int irq,void * devid)26 static irqreturn_t lt3651_charger_irq(int irq, void *devid)
27 {
28 	struct power_supply *charger = devid;
29 
30 	power_supply_changed(charger);
31 
32 	return IRQ_HANDLED;
33 }
34 
psy_to_lt3651_charger(struct power_supply * psy)35 static inline struct lt3651_charger *psy_to_lt3651_charger(
36 	struct power_supply *psy)
37 {
38 	return power_supply_get_drvdata(psy);
39 }
40 
lt3651_charger_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)41 static int lt3651_charger_get_property(struct power_supply *psy,
42 		enum power_supply_property psp, union power_supply_propval *val)
43 {
44 	struct lt3651_charger *lt3651_charger = psy_to_lt3651_charger(psy);
45 
46 	switch (psp) {
47 	case POWER_SUPPLY_PROP_STATUS:
48 		if (!lt3651_charger->chrg_gpio) {
49 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
50 			break;
51 		}
52 		if (gpiod_get_value(lt3651_charger->chrg_gpio))
53 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
54 		else
55 			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
56 		break;
57 	case POWER_SUPPLY_PROP_ONLINE:
58 		val->intval = gpiod_get_value(lt3651_charger->acpr_gpio);
59 		break;
60 	case POWER_SUPPLY_PROP_HEALTH:
61 		if (!lt3651_charger->fault_gpio) {
62 			val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
63 			break;
64 		}
65 		if (!gpiod_get_value(lt3651_charger->fault_gpio)) {
66 			val->intval = POWER_SUPPLY_HEALTH_GOOD;
67 			break;
68 		}
69 		/*
70 		 * If the fault pin is active, the chrg pin explains the type
71 		 * of failure.
72 		 */
73 		if (!lt3651_charger->chrg_gpio) {
74 			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
75 			break;
76 		}
77 		val->intval = gpiod_get_value(lt3651_charger->chrg_gpio) ?
78 				POWER_SUPPLY_HEALTH_OVERHEAT :
79 				POWER_SUPPLY_HEALTH_DEAD;
80 		break;
81 	default:
82 		return -EINVAL;
83 	}
84 
85 	return 0;
86 }
87 
88 static enum power_supply_property lt3651_charger_properties[] = {
89 	POWER_SUPPLY_PROP_STATUS,
90 	POWER_SUPPLY_PROP_ONLINE,
91 	POWER_SUPPLY_PROP_HEALTH,
92 };
93 
lt3651_charger_probe(struct platform_device * pdev)94 static int lt3651_charger_probe(struct platform_device *pdev)
95 {
96 	struct power_supply_config psy_cfg = {};
97 	struct lt3651_charger *lt3651_charger;
98 	struct power_supply_desc *charger_desc;
99 	int ret;
100 
101 	lt3651_charger = devm_kzalloc(&pdev->dev, sizeof(*lt3651_charger),
102 					GFP_KERNEL);
103 	if (!lt3651_charger)
104 		return -ENOMEM;
105 
106 	lt3651_charger->acpr_gpio = devm_gpiod_get(&pdev->dev,
107 					"lltc,acpr", GPIOD_IN);
108 	if (IS_ERR(lt3651_charger->acpr_gpio)) {
109 		ret = PTR_ERR(lt3651_charger->acpr_gpio);
110 		dev_err(&pdev->dev, "Failed to acquire acpr GPIO: %d\n", ret);
111 		return ret;
112 	}
113 	lt3651_charger->fault_gpio = devm_gpiod_get_optional(&pdev->dev,
114 					"lltc,fault", GPIOD_IN);
115 	if (IS_ERR(lt3651_charger->fault_gpio)) {
116 		ret = PTR_ERR(lt3651_charger->fault_gpio);
117 		dev_err(&pdev->dev, "Failed to acquire fault GPIO: %d\n", ret);
118 		return ret;
119 	}
120 	lt3651_charger->chrg_gpio = devm_gpiod_get_optional(&pdev->dev,
121 					"lltc,chrg", GPIOD_IN);
122 	if (IS_ERR(lt3651_charger->chrg_gpio)) {
123 		ret = PTR_ERR(lt3651_charger->chrg_gpio);
124 		dev_err(&pdev->dev, "Failed to acquire chrg GPIO: %d\n", ret);
125 		return ret;
126 	}
127 
128 	charger_desc = &lt3651_charger->charger_desc;
129 	charger_desc->name = pdev->dev.of_node->name;
130 	charger_desc->type = POWER_SUPPLY_TYPE_MAINS;
131 	charger_desc->properties = lt3651_charger_properties;
132 	charger_desc->num_properties = ARRAY_SIZE(lt3651_charger_properties);
133 	charger_desc->get_property = lt3651_charger_get_property;
134 	psy_cfg.of_node = pdev->dev.of_node;
135 	psy_cfg.drv_data = lt3651_charger;
136 
137 	lt3651_charger->charger = devm_power_supply_register(&pdev->dev,
138 						      charger_desc, &psy_cfg);
139 	if (IS_ERR(lt3651_charger->charger)) {
140 		ret = PTR_ERR(lt3651_charger->charger);
141 		dev_err(&pdev->dev, "Failed to register power supply: %d\n",
142 			ret);
143 		return ret;
144 	}
145 
146 	/*
147 	 * Acquire IRQs for the GPIO pins if possible. If the system does not
148 	 * support IRQs on these pins, userspace will have to poll the sysfs
149 	 * files manually.
150 	 */
151 	if (lt3651_charger->acpr_gpio) {
152 		ret = gpiod_to_irq(lt3651_charger->acpr_gpio);
153 		if (ret >= 0)
154 			ret = devm_request_any_context_irq(&pdev->dev, ret,
155 				lt3651_charger_irq,
156 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
157 				dev_name(&pdev->dev), lt3651_charger->charger);
158 		if (ret < 0)
159 			dev_warn(&pdev->dev, "Failed to request acpr irq\n");
160 	}
161 	if (lt3651_charger->fault_gpio) {
162 		ret = gpiod_to_irq(lt3651_charger->fault_gpio);
163 		if (ret >= 0)
164 			ret = devm_request_any_context_irq(&pdev->dev, ret,
165 				lt3651_charger_irq,
166 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
167 				dev_name(&pdev->dev), lt3651_charger->charger);
168 		if (ret < 0)
169 			dev_warn(&pdev->dev, "Failed to request fault irq\n");
170 	}
171 	if (lt3651_charger->chrg_gpio) {
172 		ret = gpiod_to_irq(lt3651_charger->chrg_gpio);
173 		if (ret >= 0)
174 			ret = devm_request_any_context_irq(&pdev->dev, ret,
175 				lt3651_charger_irq,
176 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
177 				dev_name(&pdev->dev), lt3651_charger->charger);
178 		if (ret < 0)
179 			dev_warn(&pdev->dev, "Failed to request chrg irq\n");
180 	}
181 
182 	platform_set_drvdata(pdev, lt3651_charger);
183 
184 	return 0;
185 }
186 
187 static const struct of_device_id lt3651_charger_match[] = {
188 	{ .compatible = "lltc,ltc3651-charger" }, /* DEPRECATED */
189 	{ .compatible = "lltc,lt3651-charger" },
190 	{ }
191 };
192 MODULE_DEVICE_TABLE(of, lt3651_charger_match);
193 
194 static struct platform_driver lt3651_charger_driver = {
195 	.probe = lt3651_charger_probe,
196 	.driver = {
197 		.name = "lt3651-charger",
198 		.of_match_table = lt3651_charger_match,
199 	},
200 };
201 
202 module_platform_driver(lt3651_charger_driver);
203 
204 MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
205 MODULE_DESCRIPTION("Driver for LT3651 charger");
206 MODULE_LICENSE("GPL");
207 MODULE_ALIAS("platform:lt3651-charger");
208