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
44static void __iomem *irqc;
45
46static const u8 da9063_mask_regs[] = {
47	DA9063_REG_IRQ_MASK_A,
48	DA9063_REG_IRQ_MASK_B,
49	DA9063_REG_IRQ_MASK_C,
50	DA9063_REG_IRQ_MASK_D,
51};
52
53/* DA9210 System Control and Event Registers */
54#define DA9210_REG_MASK_A		0x54
55#define DA9210_REG_MASK_B		0x55
56
57static const u8 da9210_mask_regs[] = {
58	DA9210_REG_MASK_A,
59	DA9210_REG_MASK_B,
60};
61
62static void da9xxx_mask_irqs(struct i2c_client *client, const u8 regs[],
63			     unsigned int nregs)
64{
65	unsigned int i;
66
67	dev_info(&client->dev, "Masking %s interrupt sources\n", client->name);
68
69	for (i = 0; i < nregs; i++) {
70		int error = i2c_smbus_write_byte_data(client, regs[i], ~0);
71		if (error) {
72			dev_err(&client->dev, "i2c error %d\n", error);
73			return;
74		}
75	}
76}
77
78static int regulator_quirk_notify(struct notifier_block *nb,
79				  unsigned long action, void *data)
80{
81	struct device *dev = data;
82	struct i2c_client *client;
83	u32 mon;
84
85	mon = ioread32(irqc + IRQC_MONITOR);
86	dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
87	if (mon & REGULATOR_IRQ_MASK)
88		goto remove;
89
90	if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
91		return 0;
92
93	client = to_i2c_client(dev);
94	dev_dbg(dev, "Detected %s\n", client->name);
95
96	if ((client->addr == 0x58 && !strcmp(client->name, "da9063")))
97		da9xxx_mask_irqs(client, da9063_mask_regs,
98				 ARRAY_SIZE(da9063_mask_regs));
99	else if (client->addr == 0x68 && !strcmp(client->name, "da9210"))
100		da9xxx_mask_irqs(client, da9210_mask_regs,
101				 ARRAY_SIZE(da9210_mask_regs));
102
103	mon = ioread32(irqc + IRQC_MONITOR);
104	if (mon & REGULATOR_IRQ_MASK)
105		goto remove;
106
107	return 0;
108
109remove:
110	dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
111
112	bus_unregister_notifier(&i2c_bus_type, nb);
113	iounmap(irqc);
114	return 0;
115}
116
117static struct notifier_block regulator_quirk_nb = {
118	.notifier_call = regulator_quirk_notify
119};
120
121static int __init rcar_gen2_regulator_quirk(void)
122{
123	u32 mon;
124
125	if (!of_machine_is_compatible("renesas,koelsch") &&
126	    !of_machine_is_compatible("renesas,lager"))
127		return -ENODEV;
128
129	irqc = ioremap(IRQC_BASE, PAGE_SIZE);
130	if (!irqc)
131		return -ENOMEM;
132
133	mon = ioread32(irqc + IRQC_MONITOR);
134	if (mon & REGULATOR_IRQ_MASK) {
135		pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
136			 __func__);
137		iounmap(irqc);
138		return 0;
139	}
140
141	pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
142
143	bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
144	return 0;
145}
146
147arch_initcall(rcar_gen2_regulator_quirk);
148