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// SPDX-License-Identifier: GPL-2.0
/*
* Gemini power management controller
* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
*
* Inspired by code from the SL3516 board support by Jason Lee
* Inspired by code from Janos Laube <janos.dev@gmail.com>
*/
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/reboot.h>
#define GEMINI_PWC_ID 0x00010500
#define GEMINI_PWC_IDREG 0x00
#define GEMINI_PWC_CTRLREG 0x04
#define GEMINI_PWC_STATREG 0x08
#define GEMINI_CTRL_SHUTDOWN BIT(0)
#define GEMINI_CTRL_ENABLE BIT(1)
#define GEMINI_CTRL_IRQ_CLR BIT(2)
#define GEMINI_STAT_CIR BIT(4)
#define GEMINI_STAT_RTC BIT(5)
#define GEMINI_STAT_POWERBUTTON BIT(6)
struct gemini_powercon {
struct device *dev;
void __iomem *base;
};
static irqreturn_t gemini_powerbutton_interrupt(int irq, void *data)
{
struct gemini_powercon *gpw = data;
u32 val;
/* ACK the IRQ */
val = readl(gpw->base + GEMINI_PWC_CTRLREG);
val |= GEMINI_CTRL_IRQ_CLR;
writel(val, gpw->base + GEMINI_PWC_CTRLREG);
val = readl(gpw->base + GEMINI_PWC_STATREG);
val &= 0x70U;
switch (val) {
case GEMINI_STAT_CIR:
/*
* We do not yet have a driver for the infrared
* controller so it can cause spurious poweroff
* events. Ignore those for now.
*/
dev_info(gpw->dev, "infrared poweroff - ignored\n");
break;
case GEMINI_STAT_RTC:
dev_info(gpw->dev, "RTC poweroff\n");
orderly_poweroff(true);
break;
case GEMINI_STAT_POWERBUTTON:
dev_info(gpw->dev, "poweroff button pressed\n");
orderly_poweroff(true);
break;
default:
dev_info(gpw->dev, "other power management IRQ\n");
break;
}
return IRQ_HANDLED;
}
/* This callback needs this static local as it has void as argument */
static struct gemini_powercon *gpw_poweroff;
static void gemini_poweroff(void)
{
struct gemini_powercon *gpw = gpw_poweroff;
u32 val;
dev_crit(gpw->dev, "Gemini power off\n");
val = readl(gpw->base + GEMINI_PWC_CTRLREG);
val |= GEMINI_CTRL_ENABLE | GEMINI_CTRL_IRQ_CLR;
writel(val, gpw->base + GEMINI_PWC_CTRLREG);
val &= ~GEMINI_CTRL_ENABLE;
val |= GEMINI_CTRL_SHUTDOWN;
writel(val, gpw->base + GEMINI_PWC_CTRLREG);
}
static int gemini_poweroff_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
struct gemini_powercon *gpw;
u32 val;
int irq;
int ret;
gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
if (!gpw)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
gpw->base = devm_ioremap_resource(dev, res);
if (IS_ERR(gpw->base))
return PTR_ERR(gpw->base);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
gpw->dev = dev;
val = readl(gpw->base + GEMINI_PWC_IDREG);
val &= 0xFFFFFF00U;
if (val != GEMINI_PWC_ID) {
dev_err(dev, "wrong power controller ID: %08x\n",
val);
return -ENODEV;
}
/*
* Enable the power controller. This is crucial on Gemini
* systems: if this is not done, pressing the power button
* will result in unconditional poweroff without any warning.
* This makes the kernel handle the poweroff.
*/
val = readl(gpw->base + GEMINI_PWC_CTRLREG);
val |= GEMINI_CTRL_ENABLE;
writel(val, gpw->base + GEMINI_PWC_CTRLREG);
/* Clear the IRQ */
val = readl(gpw->base + GEMINI_PWC_CTRLREG);
val |= GEMINI_CTRL_IRQ_CLR;
writel(val, gpw->base + GEMINI_PWC_CTRLREG);
/* Wait for this to clear */
val = readl(gpw->base + GEMINI_PWC_STATREG);
while (val & 0x70U)
val = readl(gpw->base + GEMINI_PWC_STATREG);
/* Clear the IRQ again */
val = readl(gpw->base + GEMINI_PWC_CTRLREG);
val |= GEMINI_CTRL_IRQ_CLR;
writel(val, gpw->base + GEMINI_PWC_CTRLREG);
ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
"poweroff", gpw);
if (ret)
return ret;
pm_power_off = gemini_poweroff;
gpw_poweroff = gpw;
dev_info(dev, "Gemini poweroff driver registered\n");
return 0;
}
static const struct of_device_id gemini_poweroff_of_match[] = {
{
.compatible = "cortina,gemini-power-controller",
},
{}
};
static struct platform_driver gemini_poweroff_driver = {
.probe = gemini_poweroff_probe,
.driver = {
.name = "gemini-poweroff",
.of_match_table = gemini_poweroff_of_match,
},
};
builtin_platform_driver(gemini_poweroff_driver);
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