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