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 		/*
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 */
74 static struct gemini_powercon *gpw_poweroff;
75 
76 static 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 
91 static 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 
161 static const struct of_device_id gemini_poweroff_of_match[] = {
162 	{
163 		.compatible = "cortina,gemini-power-controller",
164 	},
165 	{}
166 };
167 
168 static 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 };
175 builtin_platform_driver(gemini_poweroff_driver);
176