1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Driver for the external-charger IRQ pass-through function of the
4  * Intel Bay Trail Crystal Cove PMIC.
5  *
6  * Note this is NOT a power_supply class driver, it just deals with IRQ
7  * pass-through, this requires a separate driver because the PMIC's
8  * level 2 interrupt for this must be explicitly acked.
9  */
10 
11 #include <linux/interrupt.h>
12 #include <linux/irq.h>
13 #include <linux/irqdomain.h>
14 #include <linux/mfd/intel_soc_pmic.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
18 
19 #define CHGRIRQ_REG					0x0a
20 
21 struct crystal_cove_charger_data {
22 	struct mutex buslock; /* irq_bus_lock */
23 	struct irq_chip irqchip;
24 	struct regmap *regmap;
25 	struct irq_domain *irq_domain;
26 	int irq;
27 	int charger_irq;
28 	bool irq_enabled;
29 	bool irq_is_enabled;
30 };
31 
32 static irqreturn_t crystal_cove_charger_irq(int irq, void *data)
33 {
34 	struct crystal_cove_charger_data *charger = data;
35 
36 	/* No need to read CHGRIRQ_REG as there is only 1 IRQ */
37 	handle_nested_irq(charger->charger_irq);
38 
39 	/* Ack CHGRIRQ 0 */
40 	regmap_write(charger->regmap, CHGRIRQ_REG, BIT(0));
41 
42 	return IRQ_HANDLED;
43 }
44 
45 static void crystal_cove_charger_irq_bus_lock(struct irq_data *data)
46 {
47 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
48 
49 	mutex_lock(&charger->buslock);
50 }
51 
52 static void crystal_cove_charger_irq_bus_sync_unlock(struct irq_data *data)
53 {
54 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
55 
56 	if (charger->irq_is_enabled != charger->irq_enabled) {
57 		if (charger->irq_enabled)
58 			enable_irq(charger->irq);
59 		else
60 			disable_irq(charger->irq);
61 
62 		charger->irq_is_enabled = charger->irq_enabled;
63 	}
64 
65 	mutex_unlock(&charger->buslock);
66 }
67 
68 static void crystal_cove_charger_irq_unmask(struct irq_data *data)
69 {
70 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
71 
72 	charger->irq_enabled = true;
73 }
74 
75 static void crystal_cove_charger_irq_mask(struct irq_data *data)
76 {
77 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
78 
79 	charger->irq_enabled = false;
80 }
81 
82 static void crystal_cove_charger_rm_irq_domain(void *data)
83 {
84 	struct crystal_cove_charger_data *charger = data;
85 
86 	irq_domain_remove(charger->irq_domain);
87 }
88 
89 static int crystal_cove_charger_probe(struct platform_device *pdev)
90 {
91 	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
92 	struct crystal_cove_charger_data *charger;
93 	int ret;
94 
95 	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
96 	if (!charger)
97 		return -ENOMEM;
98 
99 	charger->regmap = pmic->regmap;
100 	mutex_init(&charger->buslock);
101 
102 	charger->irq = platform_get_irq(pdev, 0);
103 	if (charger->irq < 0)
104 		return charger->irq;
105 
106 	charger->irq_domain = irq_domain_create_linear(dev_fwnode(pdev->dev.parent), 1,
107 						       &irq_domain_simple_ops, NULL);
108 	if (!charger->irq_domain)
109 		return -ENOMEM;
110 
111 	/* Distuingish IRQ domain from others sharing (MFD) the same fwnode */
112 	irq_domain_update_bus_token(charger->irq_domain, DOMAIN_BUS_WAKEUP);
113 
114 	ret = devm_add_action_or_reset(&pdev->dev, crystal_cove_charger_rm_irq_domain, charger);
115 	if (ret)
116 		return ret;
117 
118 	charger->charger_irq = irq_create_mapping(charger->irq_domain, 0);
119 	if (!charger->charger_irq)
120 		return -ENOMEM;
121 
122 	charger->irqchip.name = KBUILD_MODNAME;
123 	charger->irqchip.irq_unmask = crystal_cove_charger_irq_unmask;
124 	charger->irqchip.irq_mask = crystal_cove_charger_irq_mask;
125 	charger->irqchip.irq_bus_lock = crystal_cove_charger_irq_bus_lock;
126 	charger->irqchip.irq_bus_sync_unlock = crystal_cove_charger_irq_bus_sync_unlock;
127 
128 	irq_set_chip_data(charger->charger_irq, charger);
129 	irq_set_chip_and_handler(charger->charger_irq, &charger->irqchip, handle_simple_irq);
130 	irq_set_nested_thread(charger->charger_irq, true);
131 	irq_set_noprobe(charger->charger_irq);
132 
133 	ret = devm_request_threaded_irq(&pdev->dev, charger->irq, NULL,
134 					crystal_cove_charger_irq,
135 					IRQF_ONESHOT | IRQF_NO_AUTOEN,
136 					KBUILD_MODNAME, charger);
137 	if (ret)
138 		return dev_err_probe(&pdev->dev, ret, "requesting irq\n");
139 
140 	return 0;
141 }
142 
143 static struct platform_driver crystal_cove_charger_driver = {
144 	.probe = crystal_cove_charger_probe,
145 	.driver = {
146 		.name = "crystal_cove_charger",
147 	},
148 };
149 module_platform_driver(crystal_cove_charger_driver);
150 
151 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
152 MODULE_DESCRIPTION("Intel Bay Trail Crystal Cove external charger IRQ pass-through");
153 MODULE_LICENSE("GPL");
154