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