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 
31 struct gemini_powercon {
32         struct device           *dev;
33         void __iomem            *base;
34 };
35 
36 static 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 		dev_info(gpw->dev, "infrared poweroff\n");
51 		orderly_poweroff(true);
52 		break;
53 	case GEMINI_STAT_RTC:
54 		dev_info(gpw->dev, "RTC poweroff\n");
55 		orderly_poweroff(true);
56 		break;
57 	case GEMINI_STAT_POWERBUTTON:
58 		dev_info(gpw->dev, "poweroff button pressed\n");
59 		orderly_poweroff(true);
60 		break;
61 	default:
62 		dev_info(gpw->dev, "other power management IRQ\n");
63 		break;
64 	}
65 
66 	return IRQ_HANDLED;
67 }
68 
69 /* This callback needs this static local as it has void as argument */
70 static struct gemini_powercon *gpw_poweroff;
71 
72 static void gemini_poweroff(void)
73 {
74 	struct gemini_powercon *gpw = gpw_poweroff;
75 	u32 val;
76 
77 	dev_crit(gpw->dev, "Gemini power off\n");
78 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
79 	val |= GEMINI_CTRL_ENABLE | GEMINI_CTRL_IRQ_CLR;
80 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
81 
82 	val &= ~GEMINI_CTRL_ENABLE;
83 	val |= GEMINI_CTRL_SHUTDOWN;
84 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
85 }
86 
87 static int gemini_poweroff_probe(struct platform_device *pdev)
88 {
89 	struct device *dev = &pdev->dev;
90 	struct resource *res;
91 	struct gemini_powercon *gpw;
92 	u32 val;
93 	int irq;
94 	int ret;
95 
96 	gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
97 	if (!gpw)
98 		return -ENOMEM;
99 
100 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
101 	gpw->base = devm_ioremap_resource(dev, res);
102 	if (IS_ERR(gpw->base))
103 		return PTR_ERR(gpw->base);
104 
105 	irq = platform_get_irq(pdev, 0);
106 	if (!irq)
107 		return -EINVAL;
108 
109 	gpw->dev = dev;
110 
111 	val = readl(gpw->base + GEMINI_PWC_IDREG);
112 	val &= 0xFFFFFF00U;
113 	if (val != GEMINI_PWC_ID) {
114 		dev_err(dev, "wrong power controller ID: %08x\n",
115 			val);
116 		return -ENODEV;
117 	}
118 
119 	/* Clear the power management IRQ */
120 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
121 	val |= GEMINI_CTRL_IRQ_CLR;
122 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
123 
124 	ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
125 			       "poweroff", gpw);
126 	if (ret)
127 		return ret;
128 
129 	pm_power_off = gemini_poweroff;
130 	gpw_poweroff = gpw;
131 
132 	/*
133 	 * Enable the power controller. This is crucial on Gemini
134 	 * systems: if this is not done, pressing the power button
135 	 * will result in unconditional poweroff without any warning.
136 	 * This makes the kernel handle the poweroff.
137 	 */
138 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
139 	val |= GEMINI_CTRL_ENABLE;
140 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
141 
142 	dev_info(dev, "Gemini poweroff driver registered\n");
143 
144 	return 0;
145 }
146 
147 static const struct of_device_id gemini_poweroff_of_match[] = {
148 	{
149 		.compatible = "cortina,gemini-power-controller",
150 	},
151 	{}
152 };
153 
154 static struct platform_driver gemini_poweroff_driver = {
155 	.probe = gemini_poweroff_probe,
156 	.driver = {
157 		.name = "gemini-poweroff",
158 		.of_match_table = gemini_poweroff_of_match,
159 	},
160 };
161 builtin_platform_driver(gemini_poweroff_driver);
162