1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * R-Car Generation 2 da9063/da9210 regulator quirk
4  *
5  * Certain Gen2 development boards have an da9063 and one or more da9210
6  * regulators. All of these regulators have their interrupt request lines
7  * tied to the same interrupt pin (IRQ2) on the SoC.
8  *
9  * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
10  * to assert their interrupt request lines.  Hence as soon as one driver
11  * requests this irq, it gets stuck in an interrupt storm, as it only manages
12  * to deassert its own interrupt request line, and the other driver hasn't
13  * installed an interrupt handler yet.
14  *
15  * To handle this, install a quirk that masks the interrupts in both the
16  * da9063 and da9210.  This quirk has to run after the i2c master driver has
17  * been initialized, but before the i2c slave drivers are initialized.
18  *
19  * Copyright (C) 2015 Glider bvba
20  */
21 
22 #include <linux/device.h>
23 #include <linux/i2c.h>
24 #include <linux/init.h>
25 #include <linux/io.h>
26 #include <linux/list.h>
27 #include <linux/notifier.h>
28 #include <linux/of.h>
29 #include <linux/of_irq.h>
30 #include <linux/mfd/da9063/registers.h>
31 
32 #define IRQC_BASE		0xe61c0000
33 #define IRQC_MONITOR		0x104	/* IRQn Signal Level Monitor Register */
34 
35 #define REGULATOR_IRQ_MASK	BIT(2)	/* IRQ2, active low */
36 
37 /* start of DA9210 System Control and Event Registers */
38 #define DA9210_REG_MASK_A		0x54
39 
40 struct regulator_quirk {
41 	struct list_head		list;
42 	const struct of_device_id	*id;
43 	struct of_phandle_args		irq_args;
44 	struct i2c_msg			i2c_msg;
45 	bool				shared;	/* IRQ line is shared */
46 };
47 
48 static LIST_HEAD(quirk_list);
49 static void __iomem *irqc;
50 
51 /* first byte sets the memory pointer, following are consecutive reg values */
52 static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
53 static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
54 
55 static struct i2c_msg da9063_msg = {
56 	.len = ARRAY_SIZE(da9063_irq_clr),
57 	.buf = da9063_irq_clr,
58 };
59 
60 static struct i2c_msg da9210_msg = {
61 	.len = ARRAY_SIZE(da9210_irq_clr),
62 	.buf = da9210_irq_clr,
63 };
64 
65 static const struct of_device_id rcar_gen2_quirk_match[] = {
66 	{ .compatible = "dlg,da9063", .data = &da9063_msg },
67 	{ .compatible = "dlg,da9210", .data = &da9210_msg },
68 	{},
69 };
70 
71 static int regulator_quirk_notify(struct notifier_block *nb,
72 				  unsigned long action, void *data)
73 {
74 	struct regulator_quirk *pos, *tmp;
75 	struct device *dev = data;
76 	struct i2c_client *client;
77 	static bool done;
78 	int ret;
79 	u32 mon;
80 
81 	if (done)
82 		return 0;
83 
84 	mon = ioread32(irqc + IRQC_MONITOR);
85 	dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
86 	if (mon & REGULATOR_IRQ_MASK)
87 		goto remove;
88 
89 	if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
90 		return 0;
91 
92 	client = to_i2c_client(dev);
93 	dev_dbg(dev, "Detected %s\n", client->name);
94 
95 	/*
96 	 * Send message to all PMICs that share an IRQ line to deassert it.
97 	 *
98 	 * WARNING: This works only if all the PMICs are on the same I2C bus.
99 	 */
100 	list_for_each_entry(pos, &quirk_list, list) {
101 		if (!pos->shared)
102 			continue;
103 
104 		dev_info(&client->dev, "clearing %s@0x%02x interrupts\n",
105 			 pos->id->compatible, pos->i2c_msg.addr);
106 
107 		ret = i2c_transfer(client->adapter, &pos->i2c_msg, 1);
108 		if (ret != 1)
109 			dev_err(&client->dev, "i2c error %d\n", ret);
110 	}
111 
112 	mon = ioread32(irqc + IRQC_MONITOR);
113 	if (mon & REGULATOR_IRQ_MASK)
114 		goto remove;
115 
116 	return 0;
117 
118 remove:
119 	dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
120 
121 	list_for_each_entry_safe(pos, tmp, &quirk_list, list) {
122 		list_del(&pos->list);
123 		kfree(pos);
124 	}
125 
126 	done = true;
127 	iounmap(irqc);
128 	return 0;
129 }
130 
131 static struct notifier_block regulator_quirk_nb = {
132 	.notifier_call = regulator_quirk_notify
133 };
134 
135 static int __init rcar_gen2_regulator_quirk(void)
136 {
137 	struct regulator_quirk *quirk, *pos, *tmp;
138 	struct of_phandle_args *argsa, *argsb;
139 	const struct of_device_id *id;
140 	struct device_node *np;
141 	u32 mon, addr;
142 	int ret;
143 
144 	if (!of_machine_is_compatible("renesas,koelsch") &&
145 	    !of_machine_is_compatible("renesas,lager") &&
146 	    !of_machine_is_compatible("renesas,stout") &&
147 	    !of_machine_is_compatible("renesas,gose"))
148 		return -ENODEV;
149 
150 	for_each_matching_node_and_match(np, rcar_gen2_quirk_match, &id) {
151 		if (!of_device_is_available(np))
152 			break;
153 
154 		ret = of_property_read_u32(np, "reg", &addr);
155 		if (ret)	/* Skip invalid entry and continue */
156 			continue;
157 
158 		quirk = kzalloc(sizeof(*quirk), GFP_KERNEL);
159 		if (!quirk) {
160 			ret = -ENOMEM;
161 			goto err_mem;
162 		}
163 
164 		argsa = &quirk->irq_args;
165 		memcpy(&quirk->i2c_msg, id->data, sizeof(quirk->i2c_msg));
166 
167 		quirk->id = id;
168 		quirk->i2c_msg.addr = addr;
169 
170 		ret = of_irq_parse_one(np, 0, argsa);
171 		if (ret) {	/* Skip invalid entry and continue */
172 			kfree(quirk);
173 			continue;
174 		}
175 
176 		list_for_each_entry(pos, &quirk_list, list) {
177 			argsb = &pos->irq_args;
178 
179 			if (argsa->args_count != argsb->args_count)
180 				continue;
181 
182 			ret = memcmp(argsa->args, argsb->args,
183 				     argsa->args_count *
184 				     sizeof(argsa->args[0]));
185 			if (!ret) {
186 				pos->shared = true;
187 				quirk->shared = true;
188 			}
189 		}
190 
191 		list_add_tail(&quirk->list, &quirk_list);
192 	}
193 
194 	irqc = ioremap(IRQC_BASE, PAGE_SIZE);
195 	if (!irqc) {
196 		ret = -ENOMEM;
197 		goto err_mem;
198 	}
199 
200 	mon = ioread32(irqc + IRQC_MONITOR);
201 	if (mon & REGULATOR_IRQ_MASK) {
202 		pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
203 			 __func__);
204 		ret = 0;
205 		goto err_free;
206 	}
207 
208 	pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
209 
210 	bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
211 	return 0;
212 
213 err_free:
214 	iounmap(irqc);
215 err_mem:
216 	list_for_each_entry_safe(pos, tmp, &quirk_list, list) {
217 		list_del(&pos->list);
218 		kfree(pos);
219 	}
220 
221 	return ret;
222 }
223 
224 arch_initcall(rcar_gen2_regulator_quirk);
225