rtc: st: Add new driver for ST's LPC RTC
ST's Low Power Controller (LPC) controls two devices; watchdog and RTC. Only one of the devices can be used at any one time. This is enforced by the correlating MFD driver. This portion of the driver-set controls the Real Time Clock. Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Lee Jones
Родитель
5cb69745da
Коммит
b5b2bdfc28
|
|
@ -1510,6 +1510,17 @@ config RTC_DRV_SIRFSOC
|
|||
Say "yes" here to support the real time clock on SiRF SOC chips.
|
||||
This driver can also be built as a module called rtc-sirfsoc.
|
||||
|
||||
config RTC_DRV_ST_LPC
|
||||
tristate "STMicroelectronics LPC RTC"
|
||||
depends on ARCH_STI
|
||||
depends on OF
|
||||
help
|
||||
Say Y here to include STMicroelectronics Low Power Controller
|
||||
(LPC) based RTC support.
|
||||
|
||||
To compile this driver as a module, choose M here: the
|
||||
module will be called rtc-st-lpc.
|
||||
|
||||
config RTC_DRV_MOXART
|
||||
tristate "MOXA ART RTC"
|
||||
depends on ARCH_MOXART || COMPILE_TEST
|
||||
|
|
|
|||
|
|
@ -153,4 +153,5 @@ obj-$(CONFIG_RTC_DRV_WM8350) += rtc-wm8350.o
|
|||
obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o
|
||||
obj-$(CONFIG_RTC_DRV_XGENE) += rtc-xgene.o
|
||||
obj-$(CONFIG_RTC_DRV_SIRFSOC) += rtc-sirfsoc.o
|
||||
obj-$(CONFIG_RTC_DRV_ST_LPC) += rtc-st-lpc.o
|
||||
obj-$(CONFIG_RTC_DRV_MOXART) += rtc-moxart.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,354 @@
|
|||
/*
|
||||
* rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer
|
||||
*
|
||||
* Copyright (C) 2014 STMicroelectronics Limited
|
||||
*
|
||||
* Author: David Paris <david.paris@st.com> for STMicroelectronics
|
||||
* Lee Jones <lee.jones@linaro.org> for STMicroelectronics
|
||||
*
|
||||
* Based on the original driver written by Stuart Menefy.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public Licence
|
||||
* as published by the Free Software Foundation; either version
|
||||
* 2 of the Licence, or (at your option) any later version.
|
||||
*/
|
||||
|
||||
#include <linux/clk.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/io.h>
|
||||
#include <linux/irq.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/of.h>
|
||||
#include <linux/of_irq.h>
|
||||
#include <linux/platform_device.h>
|
||||
#include <linux/rtc.h>
|
||||
|
||||
#include <dt-bindings/mfd/st-lpc.h>
|
||||
|
||||
/* Low Power Timer */
|
||||
#define LPC_LPT_LSB_OFF 0x400
|
||||
#define LPC_LPT_MSB_OFF 0x404
|
||||
#define LPC_LPT_START_OFF 0x408
|
||||
|
||||
/* Low Power Alarm */
|
||||
#define LPC_LPA_LSB_OFF 0x410
|
||||
#define LPC_LPA_MSB_OFF 0x414
|
||||
#define LPC_LPA_START_OFF 0x418
|
||||
|
||||
/* LPC as WDT */
|
||||
#define LPC_WDT_OFF 0x510
|
||||
#define LPC_WDT_FLAG_OFF 0x514
|
||||
|
||||
struct st_rtc {
|
||||
struct rtc_device *rtc_dev;
|
||||
struct rtc_wkalrm alarm;
|
||||
struct resource *res;
|
||||
struct clk *clk;
|
||||
unsigned long clkrate;
|
||||
void __iomem *ioaddr;
|
||||
bool irq_enabled:1;
|
||||
spinlock_t lock;
|
||||
short irq;
|
||||
};
|
||||
|
||||
static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
|
||||
unsigned long msb, unsigned long lsb)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
spin_lock_irqsave(&rtc->lock, flags);
|
||||
|
||||
writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
|
||||
|
||||
writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
|
||||
writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
|
||||
writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
|
||||
|
||||
writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
|
||||
|
||||
spin_unlock_irqrestore(&rtc->lock, flags);
|
||||
}
|
||||
|
||||
static irqreturn_t st_rtc_handler(int this_irq, void *data)
|
||||
{
|
||||
struct st_rtc *rtc = (struct st_rtc *)data;
|
||||
|
||||
rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);
|
||||
|
||||
return IRQ_HANDLED;
|
||||
}
|
||||
|
||||
static int st_rtc_read_time(struct device *dev, struct rtc_time *tm)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
unsigned long lpt_lsb, lpt_msb;
|
||||
unsigned long long lpt;
|
||||
unsigned long flags;
|
||||
|
||||
spin_lock_irqsave(&rtc->lock, flags);
|
||||
|
||||
do {
|
||||
lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
|
||||
lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
|
||||
} while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
|
||||
|
||||
spin_unlock_irqrestore(&rtc->lock, flags);
|
||||
|
||||
lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
|
||||
do_div(lpt, rtc->clkrate);
|
||||
rtc_time_to_tm(lpt, tm);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int st_rtc_set_time(struct device *dev, struct rtc_time *tm)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
unsigned long long lpt;
|
||||
unsigned long secs, flags;
|
||||
int ret;
|
||||
|
||||
ret = rtc_tm_to_time(tm, &secs);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
lpt = (unsigned long long)secs * rtc->clkrate;
|
||||
|
||||
spin_lock_irqsave(&rtc->lock, flags);
|
||||
|
||||
writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
|
||||
writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
|
||||
writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);
|
||||
|
||||
spin_unlock_irqrestore(&rtc->lock, flags);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
unsigned long flags;
|
||||
|
||||
spin_lock_irqsave(&rtc->lock, flags);
|
||||
|
||||
memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
|
||||
|
||||
spin_unlock_irqrestore(&rtc->lock, flags);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
|
||||
if (enabled && !rtc->irq_enabled) {
|
||||
enable_irq(rtc->irq);
|
||||
rtc->irq_enabled = true;
|
||||
} else if (!enabled && rtc->irq_enabled) {
|
||||
disable_irq(rtc->irq);
|
||||
rtc->irq_enabled = false;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
struct rtc_time now;
|
||||
unsigned long now_secs;
|
||||
unsigned long alarm_secs;
|
||||
unsigned long long lpa;
|
||||
|
||||
st_rtc_read_time(dev, &now);
|
||||
rtc_tm_to_time(&now, &now_secs);
|
||||
rtc_tm_to_time(&t->time, &alarm_secs);
|
||||
|
||||
/* Invalid alarm time */
|
||||
if (now_secs > alarm_secs)
|
||||
return -EINVAL;
|
||||
|
||||
memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
|
||||
|
||||
/* Now many secs to fire */
|
||||
alarm_secs -= now_secs;
|
||||
lpa = (unsigned long long)alarm_secs * rtc->clkrate;
|
||||
|
||||
st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
|
||||
st_rtc_alarm_irq_enable(dev, t->enabled);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct rtc_class_ops st_rtc_ops = {
|
||||
.read_time = st_rtc_read_time,
|
||||
.set_time = st_rtc_set_time,
|
||||
.read_alarm = st_rtc_read_alarm,
|
||||
.set_alarm = st_rtc_set_alarm,
|
||||
.alarm_irq_enable = st_rtc_alarm_irq_enable,
|
||||
};
|
||||
|
||||
static int st_rtc_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct device_node *np = pdev->dev.of_node;
|
||||
struct st_rtc *rtc;
|
||||
struct resource *res;
|
||||
struct rtc_time tm_check;
|
||||
uint32_t mode;
|
||||
int ret = 0;
|
||||
|
||||
ret = of_property_read_u32(np, "st,lpc-mode", &mode);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "An LPC mode must be provided\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/* LPC can either run in RTC or WDT mode */
|
||||
if (mode != ST_LPC_MODE_RTC)
|
||||
return -ENODEV;
|
||||
|
||||
rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL);
|
||||
if (!rtc)
|
||||
return -ENOMEM;
|
||||
|
||||
spin_lock_init(&rtc->lock);
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
rtc->ioaddr = devm_ioremap_resource(&pdev->dev, res);
|
||||
if (IS_ERR(rtc->ioaddr))
|
||||
return PTR_ERR(rtc->ioaddr);
|
||||
|
||||
rtc->irq = irq_of_parse_and_map(np, 0);
|
||||
if (!rtc->irq) {
|
||||
dev_err(&pdev->dev, "IRQ missing or invalid\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0,
|
||||
pdev->name, rtc);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
|
||||
return ret;
|
||||
}
|
||||
|
||||
enable_irq_wake(rtc->irq);
|
||||
disable_irq(rtc->irq);
|
||||
|
||||
rtc->clk = clk_get(&pdev->dev, NULL);
|
||||
if (IS_ERR(rtc->clk)) {
|
||||
dev_err(&pdev->dev, "Unable to request clock\n");
|
||||
return PTR_ERR(rtc->clk);
|
||||
}
|
||||
|
||||
clk_prepare_enable(rtc->clk);
|
||||
|
||||
rtc->clkrate = clk_get_rate(rtc->clk);
|
||||
if (!rtc->clkrate) {
|
||||
dev_err(&pdev->dev, "Unable to fetch clock rate\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
device_set_wakeup_capable(&pdev->dev, 1);
|
||||
|
||||
platform_set_drvdata(pdev, rtc);
|
||||
|
||||
/*
|
||||
* The RTC-LPC is able to manage date.year > 2038
|
||||
* but currently the kernel can not manage this date!
|
||||
* If the RTC-LPC has a date.year > 2038 then
|
||||
* it's set to the epoch "Jan 1st 2000"
|
||||
*/
|
||||
st_rtc_read_time(&pdev->dev, &tm_check);
|
||||
|
||||
if (tm_check.tm_year >= (2038 - 1900)) {
|
||||
memset(&tm_check, 0, sizeof(tm_check));
|
||||
tm_check.tm_year = 100;
|
||||
tm_check.tm_mday = 1;
|
||||
st_rtc_set_time(&pdev->dev, &tm_check);
|
||||
}
|
||||
|
||||
rtc->rtc_dev = rtc_device_register("st-lpc-rtc", &pdev->dev,
|
||||
&st_rtc_ops, THIS_MODULE);
|
||||
if (IS_ERR(rtc->rtc_dev)) {
|
||||
clk_disable_unprepare(rtc->clk);
|
||||
return PTR_ERR(rtc->rtc_dev);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int st_rtc_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct st_rtc *rtc = platform_get_drvdata(pdev);
|
||||
|
||||
if (likely(rtc->rtc_dev))
|
||||
rtc_device_unregister(rtc->rtc_dev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_PM_SLEEP
|
||||
static int st_rtc_suspend(struct device *dev)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
|
||||
if (device_may_wakeup(dev))
|
||||
return 0;
|
||||
|
||||
writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
|
||||
writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
|
||||
writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int st_rtc_resume(struct device *dev)
|
||||
{
|
||||
struct st_rtc *rtc = dev_get_drvdata(dev);
|
||||
|
||||
rtc_alarm_irq_enable(rtc->rtc_dev, 0);
|
||||
|
||||
/*
|
||||
* clean 'rtc->alarm' to allow a new
|
||||
* .set_alarm to the upper RTC layer
|
||||
*/
|
||||
memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
|
||||
|
||||
writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
|
||||
writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
|
||||
writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
|
||||
writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
|
||||
writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
|
||||
|
||||
return 0;
|
||||
}
|
||||
#endif
|
||||
|
||||
static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);
|
||||
|
||||
static const struct of_device_id st_rtc_match[] = {
|
||||
{ .compatible = "st,stih407-lpc" },
|
||||
{}
|
||||
};
|
||||
MODULE_DEVICE_TABLE(of, st_rtc_match);
|
||||
|
||||
static struct platform_driver st_rtc_platform_driver = {
|
||||
.driver = {
|
||||
.name = "st-lpc-rtc",
|
||||
.pm = &st_rtc_pm_ops,
|
||||
.of_match_table = st_rtc_match,
|
||||
},
|
||||
.probe = st_rtc_probe,
|
||||
.remove = st_rtc_remove,
|
||||
};
|
||||
|
||||
module_platform_driver(st_rtc_platform_driver);
|
||||
|
||||
MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
|
||||
MODULE_AUTHOR("David Paris <david.paris@st.com>");
|
||||
MODULE_LICENSE("GPL");
|
||||
Загрузка…
Ссылка в новой задаче