1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Gemini power management controller
4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
5 *
6 * Inspired by code from the SL3516 board support by Jason Lee
7 * Inspired by code from Janos Laube <janos.dev@gmail.com>
8 */
9#include <linux/of.h>
10#include <linux/of_platform.h>
11#include <linux/platform_device.h>
12#include <linux/pm.h>
13#include <linux/bitops.h>
14#include <linux/interrupt.h>
15#include <linux/io.h>
16#include <linux/reboot.h>
17
18#define GEMINI_PWC_ID		0x00010500
19#define	GEMINI_PWC_IDREG	0x00
20#define	GEMINI_PWC_CTRLREG	0x04
21#define	GEMINI_PWC_STATREG	0x08
22
23#define GEMINI_CTRL_SHUTDOWN	BIT(0)
24#define GEMINI_CTRL_ENABLE	BIT(1)
25#define GEMINI_CTRL_IRQ_CLR	BIT(2)
26
27#define GEMINI_STAT_CIR		BIT(4)
28#define	GEMINI_STAT_RTC		BIT(5)
29#define	GEMINI_STAT_POWERBUTTON	BIT(6)
30
31struct gemini_powercon {
32        struct device           *dev;
33        void __iomem            *base;
34};
35
36static irqreturn_t gemini_powerbutton_interrupt(int irq, void *data)
37{
38	struct gemini_powercon *gpw = data;
39	u32 val;
40
41	/* ACK the IRQ */
42	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
43	val |= GEMINI_CTRL_IRQ_CLR;
44	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
45
46	val = readl(gpw->base + GEMINI_PWC_STATREG);
47	val &= 0x70U;
48	switch (val) {
49	case GEMINI_STAT_CIR:
50		/*
51		 * We do not yet have a driver for the infrared
52		 * controller so it can cause spurious poweroff
53		 * events. Ignore those for now.
54		 */
55		dev_info(gpw->dev, "infrared poweroff - ignored\n");
56		break;
57	case GEMINI_STAT_RTC:
58		dev_info(gpw->dev, "RTC poweroff\n");
59		orderly_poweroff(true);
60		break;
61	case GEMINI_STAT_POWERBUTTON:
62		dev_info(gpw->dev, "poweroff button pressed\n");
63		orderly_poweroff(true);
64		break;
65	default:
66		dev_info(gpw->dev, "other power management IRQ\n");
67		break;
68	}
69
70	return IRQ_HANDLED;
71}
72
73/* This callback needs this static local as it has void as argument */
74static struct gemini_powercon *gpw_poweroff;
75
76static void gemini_poweroff(void)
77{
78	struct gemini_powercon *gpw = gpw_poweroff;
79	u32 val;
80
81	dev_crit(gpw->dev, "Gemini power off\n");
82	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
83	val |= GEMINI_CTRL_ENABLE | GEMINI_CTRL_IRQ_CLR;
84	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
85
86	val &= ~GEMINI_CTRL_ENABLE;
87	val |= GEMINI_CTRL_SHUTDOWN;
88	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
89}
90
91static int gemini_poweroff_probe(struct platform_device *pdev)
92{
93	struct device *dev = &pdev->dev;
94	struct resource *res;
95	struct gemini_powercon *gpw;
96	u32 val;
97	int irq;
98	int ret;
99
100	gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
101	if (!gpw)
102		return -ENOMEM;
103
104	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
105	gpw->base = devm_ioremap_resource(dev, res);
106	if (IS_ERR(gpw->base))
107		return PTR_ERR(gpw->base);
108
109	irq = platform_get_irq(pdev, 0);
110	if (irq < 0)
111		return irq;
112
113	gpw->dev = dev;
114
115	val = readl(gpw->base + GEMINI_PWC_IDREG);
116	val &= 0xFFFFFF00U;
117	if (val != GEMINI_PWC_ID) {
118		dev_err(dev, "wrong power controller ID: %08x\n",
119			val);
120		return -ENODEV;
121	}
122
123	/*
124	 * Enable the power controller. This is crucial on Gemini
125	 * systems: if this is not done, pressing the power button
126	 * will result in unconditional poweroff without any warning.
127	 * This makes the kernel handle the poweroff.
128	 */
129	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
130	val |= GEMINI_CTRL_ENABLE;
131	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
132
133	/* Clear the IRQ */
134	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
135	val |= GEMINI_CTRL_IRQ_CLR;
136	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
137
138	/* Wait for this to clear */
139	val = readl(gpw->base + GEMINI_PWC_STATREG);
140	while (val & 0x70U)
141		val = readl(gpw->base + GEMINI_PWC_STATREG);
142
143	/* Clear the IRQ again */
144	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
145	val |= GEMINI_CTRL_IRQ_CLR;
146	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
147
148	ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
149			       "poweroff", gpw);
150	if (ret)
151		return ret;
152
153	pm_power_off = gemini_poweroff;
154	gpw_poweroff = gpw;
155
156	dev_info(dev, "Gemini poweroff driver registered\n");
157
158	return 0;
159}
160
161static const struct of_device_id gemini_poweroff_of_match[] = {
162	{
163		.compatible = "cortina,gemini-power-controller",
164	},
165	{}
166};
167
168static struct platform_driver gemini_poweroff_driver = {
169	.probe = gemini_poweroff_probe,
170	.driver = {
171		.name = "gemini-poweroff",
172		.of_match_table = gemini_poweroff_of_match,
173	},
174};
175builtin_platform_driver(gemini_poweroff_driver);
176