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 #define MCHGRIRQ_REG					0x17
21 
22 struct crystal_cove_charger_data {
23 	struct mutex buslock; /* irq_bus_lock */
24 	struct irq_chip irqchip;
25 	struct regmap *regmap;
26 	struct irq_domain *irq_domain;
27 	int irq;
28 	int charger_irq;
29 	u8 mask;
30 	u8 new_mask;
31 };
32 
crystal_cove_charger_irq(int irq,void * data)33 static irqreturn_t crystal_cove_charger_irq(int irq, void *data)
34 {
35 	struct crystal_cove_charger_data *charger = data;
36 
37 	/* No need to read CHGRIRQ_REG as there is only 1 IRQ */
38 	handle_nested_irq(charger->charger_irq);
39 
40 	/* Ack CHGRIRQ 0 */
41 	regmap_write(charger->regmap, CHGRIRQ_REG, BIT(0));
42 
43 	return IRQ_HANDLED;
44 }
45 
crystal_cove_charger_irq_bus_lock(struct irq_data * data)46 static void crystal_cove_charger_irq_bus_lock(struct irq_data *data)
47 {
48 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
49 
50 	mutex_lock(&charger->buslock);
51 }
52 
crystal_cove_charger_irq_bus_sync_unlock(struct irq_data * data)53 static void crystal_cove_charger_irq_bus_sync_unlock(struct irq_data *data)
54 {
55 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
56 
57 	if (charger->mask != charger->new_mask) {
58 		regmap_write(charger->regmap, MCHGRIRQ_REG, charger->new_mask);
59 		charger->mask = charger->new_mask;
60 	}
61 
62 	mutex_unlock(&charger->buslock);
63 }
64 
crystal_cove_charger_irq_unmask(struct irq_data * data)65 static void crystal_cove_charger_irq_unmask(struct irq_data *data)
66 {
67 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
68 
69 	charger->new_mask &= ~BIT(data->hwirq);
70 }
71 
crystal_cove_charger_irq_mask(struct irq_data * data)72 static void crystal_cove_charger_irq_mask(struct irq_data *data)
73 {
74 	struct crystal_cove_charger_data *charger = irq_data_get_irq_chip_data(data);
75 
76 	charger->new_mask |= BIT(data->hwirq);
77 }
78 
crystal_cove_charger_rm_irq_domain(void * data)79 static void crystal_cove_charger_rm_irq_domain(void *data)
80 {
81 	struct crystal_cove_charger_data *charger = data;
82 
83 	irq_domain_remove(charger->irq_domain);
84 }
85 
crystal_cove_charger_probe(struct platform_device * pdev)86 static int crystal_cove_charger_probe(struct platform_device *pdev)
87 {
88 	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
89 	struct crystal_cove_charger_data *charger;
90 	int ret;
91 
92 	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
93 	if (!charger)
94 		return -ENOMEM;
95 
96 	charger->regmap = pmic->regmap;
97 	mutex_init(&charger->buslock);
98 
99 	charger->irq = platform_get_irq(pdev, 0);
100 	if (charger->irq < 0)
101 		return charger->irq;
102 
103 	charger->irq_domain = irq_domain_create_linear(dev_fwnode(pdev->dev.parent), 1,
104 						       &irq_domain_simple_ops, NULL);
105 	if (!charger->irq_domain)
106 		return -ENOMEM;
107 
108 	/* Distuingish IRQ domain from others sharing (MFD) the same fwnode */
109 	irq_domain_update_bus_token(charger->irq_domain, DOMAIN_BUS_WAKEUP);
110 
111 	ret = devm_add_action_or_reset(&pdev->dev, crystal_cove_charger_rm_irq_domain, charger);
112 	if (ret)
113 		return ret;
114 
115 	charger->charger_irq = irq_create_mapping(charger->irq_domain, 0);
116 	if (!charger->charger_irq)
117 		return -ENOMEM;
118 
119 	charger->irqchip.name = KBUILD_MODNAME;
120 	charger->irqchip.irq_unmask = crystal_cove_charger_irq_unmask;
121 	charger->irqchip.irq_mask = crystal_cove_charger_irq_mask;
122 	charger->irqchip.irq_bus_lock = crystal_cove_charger_irq_bus_lock;
123 	charger->irqchip.irq_bus_sync_unlock = crystal_cove_charger_irq_bus_sync_unlock;
124 
125 	irq_set_chip_data(charger->charger_irq, charger);
126 	irq_set_chip_and_handler(charger->charger_irq, &charger->irqchip, handle_simple_irq);
127 	irq_set_nested_thread(charger->charger_irq, true);
128 	irq_set_noprobe(charger->charger_irq);
129 
130 	/* Mask the single 2nd level IRQ before enabling the 1st level IRQ */
131 	charger->mask = charger->new_mask = BIT(0);
132 	regmap_write(charger->regmap, MCHGRIRQ_REG, charger->mask);
133 
134 	ret = devm_request_threaded_irq(&pdev->dev, charger->irq, NULL,
135 					crystal_cove_charger_irq,
136 					IRQF_ONESHOT, 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