xref: /linux/drivers/power/reset/gemini-poweroff.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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 
gemini_powerbutton_interrupt(int irq,void * data)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 
gemini_poweroff(struct sys_off_data * data)73 static int gemini_poweroff(struct sys_off_data *data)
74 {
75 	struct gemini_powercon *gpw = data->cb_data;
76 	u32 val;
77 
78 	dev_crit(gpw->dev, "Gemini power off\n");
79 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
80 	val |= GEMINI_CTRL_ENABLE | GEMINI_CTRL_IRQ_CLR;
81 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
82 
83 	val &= ~GEMINI_CTRL_ENABLE;
84 	val |= GEMINI_CTRL_SHUTDOWN;
85 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
86 
87 	return NOTIFY_DONE;
88 }
89 
gemini_poweroff_probe(struct platform_device * pdev)90 static int gemini_poweroff_probe(struct platform_device *pdev)
91 {
92 	struct device *dev = &pdev->dev;
93 	struct gemini_powercon *gpw;
94 	u32 val;
95 	int irq;
96 	int ret;
97 
98 	gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
99 	if (!gpw)
100 		return -ENOMEM;
101 
102 	gpw->base = devm_platform_ioremap_resource(pdev, 0);
103 	if (IS_ERR(gpw->base))
104 		return PTR_ERR(gpw->base);
105 
106 	irq = platform_get_irq(pdev, 0);
107 	if (irq < 0)
108 		return irq;
109 
110 	gpw->dev = dev;
111 
112 	val = readl(gpw->base + GEMINI_PWC_IDREG);
113 	val &= 0xFFFFFF00U;
114 	if (val != GEMINI_PWC_ID) {
115 		dev_err(dev, "wrong power controller ID: %08x\n",
116 			val);
117 		return -ENODEV;
118 	}
119 
120 	/*
121 	 * Enable the power controller. This is crucial on Gemini
122 	 * systems: if this is not done, pressing the power button
123 	 * will result in unconditional poweroff without any warning.
124 	 * This makes the kernel handle the poweroff.
125 	 */
126 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
127 	val |= GEMINI_CTRL_ENABLE;
128 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
129 
130 	/* Clear the IRQ */
131 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
132 	val |= GEMINI_CTRL_IRQ_CLR;
133 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
134 
135 	/* Wait for this to clear */
136 	val = readl(gpw->base + GEMINI_PWC_STATREG);
137 	while (val & 0x70U)
138 		val = readl(gpw->base + GEMINI_PWC_STATREG);
139 
140 	/* Clear the IRQ again */
141 	val = readl(gpw->base + GEMINI_PWC_CTRLREG);
142 	val |= GEMINI_CTRL_IRQ_CLR;
143 	writel(val, gpw->base + GEMINI_PWC_CTRLREG);
144 
145 	ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
146 			       "poweroff", gpw);
147 	if (ret)
148 		return ret;
149 
150 	ret = devm_register_sys_off_handler(dev, SYS_OFF_MODE_POWER_OFF,
151 					    SYS_OFF_PRIO_DEFAULT,
152 					    gemini_poweroff, gpw);
153 	if (ret)
154 		return ret;
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