1 /*
2  * R-Car Generation 2 da9063/da9210 regulator quirk
3  *
4  * The r8a7790/lager and r8a7791/koelsch development boards have da9063 and
5  * da9210 regulators.  Both regulators have their interrupt request lines tied
6  * to the same interrupt pin (IRQ2) on the SoC.
7  *
8  * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
9  * to assert their interrupt request lines.  Hence as soon as one driver
10  * requests this irq, it gets stuck in an interrupt storm, as it only manages
11  * to deassert its own interrupt request line, and the other driver hasn't
12  * installed an interrupt handler yet.
13  *
14  * To handle this, install a quirk that masks the interrupts in both the
15  * da9063 and da9210.  This quirk has to run after the i2c master driver has
16  * been initialized, but before the i2c slave drivers are initialized.
17  *
18  * Copyright (C) 2015 Glider bvba
19  *
20  * This program is free software; you can redistribute it and/or modify
21  * it under the terms of the GNU General Public License as published by
22  * the Free Software Foundation; version 2 of the License.
23  *
24  * This program is distributed in the hope that it will be useful,
25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
27  * GNU General Public License for more details.
28  */
29 
30 #include <linux/device.h>
31 #include <linux/i2c.h>
32 #include <linux/init.h>
33 #include <linux/io.h>
34 #include <linux/notifier.h>
35 #include <linux/of.h>
36 #include <linux/mfd/da9063/registers.h>
37 
38 
39 #define IRQC_BASE		0xe61c0000
40 #define IRQC_MONITOR		0x104	/* IRQn Signal Level Monitor Register */
41 
42 #define REGULATOR_IRQ_MASK	BIT(2)	/* IRQ2, active low */
43 
44 /* start of DA9210 System Control and Event Registers */
45 #define DA9210_REG_MASK_A		0x54
46 
47 static void __iomem *irqc;
48 
49 /* first byte sets the memory pointer, following are consecutive reg values */
50 static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
51 static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
52 
53 static struct i2c_msg da9xxx_msgs[2] = {
54 	{
55 		.addr = 0x58,
56 		.len = ARRAY_SIZE(da9063_irq_clr),
57 		.buf = da9063_irq_clr,
58 	}, {
59 		.addr = 0x68,
60 		.len = ARRAY_SIZE(da9210_irq_clr),
61 		.buf = da9210_irq_clr,
62 	},
63 };
64 
65 static int regulator_quirk_notify(struct notifier_block *nb,
66 				  unsigned long action, void *data)
67 {
68 	struct device *dev = data;
69 	struct i2c_client *client;
70 	static bool done;
71 	u32 mon;
72 
73 	if (done)
74 		return 0;
75 
76 	mon = ioread32(irqc + IRQC_MONITOR);
77 	dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
78 	if (mon & REGULATOR_IRQ_MASK)
79 		goto remove;
80 
81 	if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
82 		return 0;
83 
84 	client = to_i2c_client(dev);
85 	dev_dbg(dev, "Detected %s\n", client->name);
86 
87 	if ((client->addr == 0x58 && !strcmp(client->name, "da9063")) ||
88 	    (client->addr == 0x68 && !strcmp(client->name, "da9210"))) {
89 		int ret;
90 
91 		dev_info(&client->dev, "clearing da9063/da9210 interrupts\n");
92 		ret = i2c_transfer(client->adapter, da9xxx_msgs, ARRAY_SIZE(da9xxx_msgs));
93 		if (ret != ARRAY_SIZE(da9xxx_msgs))
94 			dev_err(&client->dev, "i2c error %d\n", ret);
95 	}
96 
97 	mon = ioread32(irqc + IRQC_MONITOR);
98 	if (mon & REGULATOR_IRQ_MASK)
99 		goto remove;
100 
101 	return 0;
102 
103 remove:
104 	dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
105 
106 	done = true;
107 	iounmap(irqc);
108 	return 0;
109 }
110 
111 static struct notifier_block regulator_quirk_nb = {
112 	.notifier_call = regulator_quirk_notify
113 };
114 
115 static int __init rcar_gen2_regulator_quirk(void)
116 {
117 	u32 mon;
118 
119 	if (!of_machine_is_compatible("renesas,koelsch") &&
120 	    !of_machine_is_compatible("renesas,lager") &&
121 	    !of_machine_is_compatible("renesas,gose"))
122 		return -ENODEV;
123 
124 	irqc = ioremap(IRQC_BASE, PAGE_SIZE);
125 	if (!irqc)
126 		return -ENOMEM;
127 
128 	mon = ioread32(irqc + IRQC_MONITOR);
129 	if (mon & REGULATOR_IRQ_MASK) {
130 		pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
131 			 __func__);
132 		iounmap(irqc);
133 		return 0;
134 	}
135 
136 	pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
137 
138 	bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
139 	return 0;
140 }
141 
142 arch_initcall(rcar_gen2_regulator_quirk);
143