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
73 /* This callback needs this static local as it has void as argument */
74 static struct gemini_powercon *gpw_poweroff;
75
gemini_poweroff(void)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
gemini_poweroff_probe(struct platform_device * pdev)91 static int gemini_poweroff_probe(struct platform_device *pdev)
92 {
93 struct device *dev = &pdev->dev;
94 struct gemini_powercon *gpw;
95 u32 val;
96 int irq;
97 int ret;
98
99 gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
100 if (!gpw)
101 return -ENOMEM;
102
103 gpw->base = devm_platform_ioremap_resource(pdev, 0);
104 if (IS_ERR(gpw->base))
105 return PTR_ERR(gpw->base);
106
107 irq = platform_get_irq(pdev, 0);
108 if (irq < 0)
109 return irq;
110
111 gpw->dev = dev;
112
113 val = readl(gpw->base + GEMINI_PWC_IDREG);
114 val &= 0xFFFFFF00U;
115 if (val != GEMINI_PWC_ID) {
116 dev_err(dev, "wrong power controller ID: %08x\n",
117 val);
118 return -ENODEV;
119 }
120
121 /*
122 * Enable the power controller. This is crucial on Gemini
123 * systems: if this is not done, pressing the power button
124 * will result in unconditional poweroff without any warning.
125 * This makes the kernel handle the poweroff.
126 */
127 val = readl(gpw->base + GEMINI_PWC_CTRLREG);
128 val |= GEMINI_CTRL_ENABLE;
129 writel(val, gpw->base + GEMINI_PWC_CTRLREG);
130
131 /* Clear the IRQ */
132 val = readl(gpw->base + GEMINI_PWC_CTRLREG);
133 val |= GEMINI_CTRL_IRQ_CLR;
134 writel(val, gpw->base + GEMINI_PWC_CTRLREG);
135
136 /* Wait for this to clear */
137 val = readl(gpw->base + GEMINI_PWC_STATREG);
138 while (val & 0x70U)
139 val = readl(gpw->base + GEMINI_PWC_STATREG);
140
141 /* Clear the IRQ again */
142 val = readl(gpw->base + GEMINI_PWC_CTRLREG);
143 val |= GEMINI_CTRL_IRQ_CLR;
144 writel(val, gpw->base + GEMINI_PWC_CTRLREG);
145
146 ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
147 "poweroff", gpw);
148 if (ret)
149 return ret;
150
151 pm_power_off = gemini_poweroff;
152 gpw_poweroff = gpw;
153
154 dev_info(dev, "Gemini poweroff driver registered\n");
155
156 return 0;
157 }
158
159 static const struct of_device_id gemini_poweroff_of_match[] = {
160 {
161 .compatible = "cortina,gemini-power-controller",
162 },
163 {}
164 };
165
166 static struct platform_driver gemini_poweroff_driver = {
167 .probe = gemini_poweroff_probe,
168 .driver = {
169 .name = "gemini-poweroff",
170 .of_match_table = gemini_poweroff_of_match,
171 },
172 };
173 builtin_platform_driver(gemini_poweroff_driver);
174