279 lines
6.5 KiB
C
279 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* APM X-Gene SoC Real Time Clock Driver
|
|
*
|
|
* Copyright (c) 2014, Applied Micro Circuits Corporation
|
|
* Author: Rameshwar Prasad Sahu <rsahu@apm.com>
|
|
* Loc Ho <lho@apm.com>
|
|
*/
|
|
|
|
#include <linux/clk.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/init.h>
|
|
#include <linux/io.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/rtc.h>
|
|
#include <linux/slab.h>
|
|
|
|
/* RTC CSR Registers */
|
|
#define RTC_CCVR 0x00
|
|
#define RTC_CMR 0x04
|
|
#define RTC_CLR 0x08
|
|
#define RTC_CCR 0x0C
|
|
#define RTC_CCR_IE BIT(0)
|
|
#define RTC_CCR_MASK BIT(1)
|
|
#define RTC_CCR_EN BIT(2)
|
|
#define RTC_CCR_WEN BIT(3)
|
|
#define RTC_STAT 0x10
|
|
#define RTC_STAT_BIT BIT(0)
|
|
#define RTC_RSTAT 0x14
|
|
#define RTC_EOI 0x18
|
|
#define RTC_VER 0x1C
|
|
|
|
struct xgene_rtc_dev {
|
|
struct rtc_device *rtc;
|
|
void __iomem *csr_base;
|
|
struct clk *clk;
|
|
unsigned int irq_wake;
|
|
unsigned int irq_enabled;
|
|
};
|
|
|
|
static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
|
|
|
|
rtc_time64_to_tm(readl(pdata->csr_base + RTC_CCVR), tm);
|
|
return 0;
|
|
}
|
|
|
|
static int xgene_rtc_set_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
|
|
|
|
/*
|
|
* NOTE: After the following write, the RTC_CCVR is only reflected
|
|
* after the update cycle of 1 seconds.
|
|
*/
|
|
writel((u32)rtc_tm_to_time64(tm), pdata->csr_base + RTC_CLR);
|
|
readl(pdata->csr_base + RTC_CLR); /* Force a barrier */
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int xgene_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
|
|
{
|
|
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
|
|
|
|
/* If possible, CMR should be read here */
|
|
rtc_time64_to_tm(0, &alrm->time);
|
|
alrm->enabled = readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int xgene_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
|
|
{
|
|
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
|
|
u32 ccr;
|
|
|
|
ccr = readl(pdata->csr_base + RTC_CCR);
|
|
if (enabled) {
|
|
ccr &= ~RTC_CCR_MASK;
|
|
ccr |= RTC_CCR_IE;
|
|
} else {
|
|
ccr &= ~RTC_CCR_IE;
|
|
ccr |= RTC_CCR_MASK;
|
|
}
|
|
writel(ccr, pdata->csr_base + RTC_CCR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int xgene_rtc_alarm_irq_enabled(struct device *dev)
|
|
{
|
|
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
|
|
|
|
return readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE ? 1 : 0;
|
|
}
|
|
|
|
static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
|
|
{
|
|
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
|
|
|
|
writel((u32)rtc_tm_to_time64(&alrm->time), pdata->csr_base + RTC_CMR);
|
|
|
|
xgene_rtc_alarm_irq_enable(dev, alrm->enabled);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct rtc_class_ops xgene_rtc_ops = {
|
|
.read_time = xgene_rtc_read_time,
|
|
.set_time = xgene_rtc_set_time,
|
|
.read_alarm = xgene_rtc_read_alarm,
|
|
.set_alarm = xgene_rtc_set_alarm,
|
|
.alarm_irq_enable = xgene_rtc_alarm_irq_enable,
|
|
};
|
|
|
|
static irqreturn_t xgene_rtc_interrupt(int irq, void *id)
|
|
{
|
|
struct xgene_rtc_dev *pdata = id;
|
|
|
|
/* Check if interrupt asserted */
|
|
if (!(readl(pdata->csr_base + RTC_STAT) & RTC_STAT_BIT))
|
|
return IRQ_NONE;
|
|
|
|
/* Clear interrupt */
|
|
readl(pdata->csr_base + RTC_EOI);
|
|
|
|
rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static int xgene_rtc_probe(struct platform_device *pdev)
|
|
{
|
|
struct xgene_rtc_dev *pdata;
|
|
int ret;
|
|
int irq;
|
|
|
|
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
|
|
if (!pdata)
|
|
return -ENOMEM;
|
|
platform_set_drvdata(pdev, pdata);
|
|
|
|
pdata->csr_base = devm_platform_ioremap_resource(pdev, 0);
|
|
if (IS_ERR(pdata->csr_base))
|
|
return PTR_ERR(pdata->csr_base);
|
|
|
|
pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
|
|
if (IS_ERR(pdata->rtc))
|
|
return PTR_ERR(pdata->rtc);
|
|
|
|
irq = platform_get_irq(pdev, 0);
|
|
if (irq < 0)
|
|
return irq;
|
|
ret = devm_request_irq(&pdev->dev, irq, xgene_rtc_interrupt, 0,
|
|
dev_name(&pdev->dev), pdata);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "Could not request IRQ\n");
|
|
return ret;
|
|
}
|
|
|
|
pdata->clk = devm_clk_get(&pdev->dev, NULL);
|
|
if (IS_ERR(pdata->clk)) {
|
|
dev_err(&pdev->dev, "Couldn't get the clock for RTC\n");
|
|
return -ENODEV;
|
|
}
|
|
ret = clk_prepare_enable(pdata->clk);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Turn on the clock and the crystal */
|
|
writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR);
|
|
|
|
ret = device_init_wakeup(&pdev->dev, 1);
|
|
if (ret) {
|
|
clk_disable_unprepare(pdata->clk);
|
|
return ret;
|
|
}
|
|
|
|
pdata->rtc->ops = &xgene_rtc_ops;
|
|
pdata->rtc->range_max = U32_MAX;
|
|
|
|
ret = devm_rtc_register_device(pdata->rtc);
|
|
if (ret) {
|
|
clk_disable_unprepare(pdata->clk);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void xgene_rtc_remove(struct platform_device *pdev)
|
|
{
|
|
struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
|
|
|
|
xgene_rtc_alarm_irq_enable(&pdev->dev, 0);
|
|
device_init_wakeup(&pdev->dev, 0);
|
|
clk_disable_unprepare(pdata->clk);
|
|
}
|
|
|
|
static int __maybe_unused xgene_rtc_suspend(struct device *dev)
|
|
{
|
|
struct platform_device *pdev = to_platform_device(dev);
|
|
struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
|
|
int irq;
|
|
|
|
irq = platform_get_irq(pdev, 0);
|
|
|
|
/*
|
|
* If this RTC alarm will be used for waking the system up,
|
|
* don't disable it of course. Else we just disable the alarm
|
|
* and await suspension.
|
|
*/
|
|
if (device_may_wakeup(&pdev->dev)) {
|
|
if (!enable_irq_wake(irq))
|
|
pdata->irq_wake = 1;
|
|
} else {
|
|
pdata->irq_enabled = xgene_rtc_alarm_irq_enabled(dev);
|
|
xgene_rtc_alarm_irq_enable(dev, 0);
|
|
clk_disable_unprepare(pdata->clk);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __maybe_unused xgene_rtc_resume(struct device *dev)
|
|
{
|
|
struct platform_device *pdev = to_platform_device(dev);
|
|
struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
|
|
int irq;
|
|
int rc;
|
|
|
|
irq = platform_get_irq(pdev, 0);
|
|
|
|
if (device_may_wakeup(&pdev->dev)) {
|
|
if (pdata->irq_wake) {
|
|
disable_irq_wake(irq);
|
|
pdata->irq_wake = 0;
|
|
}
|
|
} else {
|
|
rc = clk_prepare_enable(pdata->clk);
|
|
if (rc) {
|
|
dev_err(dev, "Unable to enable clock error %d\n", rc);
|
|
return rc;
|
|
}
|
|
xgene_rtc_alarm_irq_enable(dev, pdata->irq_enabled);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static SIMPLE_DEV_PM_OPS(xgene_rtc_pm_ops, xgene_rtc_suspend, xgene_rtc_resume);
|
|
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id xgene_rtc_of_match[] = {
|
|
{.compatible = "apm,xgene-rtc" },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, xgene_rtc_of_match);
|
|
#endif
|
|
|
|
static struct platform_driver xgene_rtc_driver = {
|
|
.probe = xgene_rtc_probe,
|
|
.remove_new = xgene_rtc_remove,
|
|
.driver = {
|
|
.name = "xgene-rtc",
|
|
.pm = &xgene_rtc_pm_ops,
|
|
.of_match_table = of_match_ptr(xgene_rtc_of_match),
|
|
},
|
|
};
|
|
|
|
module_platform_driver(xgene_rtc_driver);
|
|
|
|
MODULE_DESCRIPTION("APM X-Gene SoC RTC driver");
|
|
MODULE_AUTHOR("Rameshwar Sahu <rsahu@apm.com>");
|
|
MODULE_LICENSE("GPL");
|