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
 31struct gemini_powercon {
 32        struct device           *dev;
 33        void __iomem            *base;
 34};
 35
 36static 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 */
 74static struct gemini_powercon *gpw_poweroff;
 75
 76static 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
 91static 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
159static const struct of_device_id gemini_poweroff_of_match[] = {
160	{
161		.compatible = "cortina,gemini-power-controller",
162	},
163	{}
164};
165
166static 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};
173builtin_platform_driver(gemini_poweroff_driver);