satip-axe/kernel/drivers/rtc/rtc-stm-sys.c
2015-03-26 17:24:57 +01:00

310 lines
6.9 KiB
C

/*
* This driver implements a RTC using the Low Power Timer in
* the System Service of stx5197 STMicroelectronics devices.
*
* See ADCS 8101263B for more details on the hardware.
*
* Copyright (C) 2010 STMicroelectronics Limited
* Author: Francesco Virlinzi <francesco.virlinzi@st.com>
*
* May be copied or modified under the terms of the GNU General Public
* License. See linux/COPYING for more information.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/stm/platform.h>
#include <linux/stm/clk.h>
#define DRV_NAME "stm-rtc"
#define DRV_VERSION "0.1"
#define SS_LOCK_CFG 0x300
/* Low Power Timer */
#define LPC_LPT_LSB_OFF 0x200
#define LPC_LPT_MSB_OFF 0x204
#define LPC_LPT_START_OFF 0x208
/* Low Power Alarm */
#define LPC_LPA_LSB_OFF 0x120
#define LPC_LPA_LSB_MASK 0xffff
#define LPC_LPA_MSB_OFF 0x124
#define LPC_LPA_MSB_MASK 0x00f
#define LPC_LPA_START_ENABLE (1 << 4)
#define LPA_CLK 27000000
struct stm_rtc {
struct rtc_device *rtc_dev;
void __iomem *ioaddr;
struct resource *res;
spinlock_t lock;
struct rtc_wkalrm alarm;
};
static void _rtc_hw_unlock(struct stm_rtc *rtc)
{
writel(0xf0, rtc->ioaddr + SS_LOCK_CFG);
writel(0x0f, rtc->ioaddr + SS_LOCK_CFG);
}
static void _rtc_hw_lock(struct stm_rtc *rtc)
{
writel(0x100, rtc->ioaddr + SS_LOCK_CFG);
}
static int stm_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
unsigned long long lpt;
unsigned long lpt_lsb, lpt_msb;
spin_lock(&rtc->lock);
do {
lpt_msb = readl(rtc->ioaddr + LPC_LPT_MSB_OFF);
lpt_lsb = readl(rtc->ioaddr + LPC_LPT_LSB_OFF);
} while (readl(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
do_div(lpt, LPA_CLK);
rtc_time_to_tm(lpt, tm);
spin_unlock(&rtc->lock);
return 0;
}
static int stm_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
unsigned long secs;
int ret;
unsigned long long lpt;
ret = rtc_tm_to_time(tm, &secs);
if (ret != 0)
return ret;
pr_info("%s\n", __func__);
spin_lock(&rtc->lock);
lpt = secs * LPA_CLK;
_rtc_hw_unlock(rtc);
writel(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
writel(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
writel(1, rtc->ioaddr + LPC_LPT_START_OFF);
_rtc_hw_lock(rtc);
spin_unlock(&rtc->lock);
return 0;
}
static int stm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
spin_lock(&rtc->lock);
memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
spin_unlock(&rtc->lock);
return 0;
}
static int stm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
struct rtc_time now;
unsigned long now_secs;
unsigned long alarm_secs;
pr_info("%s\n", __func__);
stm_rtc_read_time(dev, &now);
rtc_tm_to_time(&now, &now_secs);
rtc_tm_to_time(&t->time, &alarm_secs);
if (now_secs > alarm_secs)
return -EINVAL; /* invalid alarm time */
device_set_wakeup_enable(dev, 1);
memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
alarm_secs -= now_secs; /* now many secs to fire */
spin_lock(&rtc->lock);
_rtc_hw_unlock(rtc);
writel(alarm_secs & LPC_LPA_LSB_MASK,
rtc->ioaddr + LPC_LPA_LSB_OFF);
writel(((alarm_secs >> 16) & LPC_LPA_MSB_MASK)
| LPC_LPA_START_ENABLE, rtc->ioaddr + LPC_LPA_MSB_OFF);
_rtc_hw_lock(rtc);
spin_unlock(&rtc->lock);
return 0;
}
static struct rtc_class_ops stm_rtc_ops = {
.read_time = stm_rtc_read_time,
.set_time = stm_rtc_set_time,
.read_alarm = stm_rtc_read_alarm,
.set_alarm = stm_rtc_set_alarm,
};
#ifdef CONFIG_PM
static int stm_rtc_resume(struct device *dev)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
pr_info("Resetting rtc-lpc devices\n");
/*
* it needs to clean the 'rtc->alarm' to allow
* a new .set_alarm to the upper RTC layer
*/
memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
spin_lock(&rtc->lock);
/* turn-off the alarm */
_rtc_hw_unlock(rtc);
writel(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
writel(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
_rtc_hw_lock(rtc);
spin_unlock(&rtc->lock);
return 0;
}
static int stm_rtc_suspend(struct device *dev)
{
if (device_may_wakeup(dev))
return 0;
return stm_rtc_resume(dev);
}
static struct dev_pm_ops stm_rtc_pm_ops = {
.suspend = stm_rtc_suspend, /* on standby/memstandby */
.resume = stm_rtc_resume,
};
#endif
static int __devinit stm_rtc_probe(struct platform_device *pdev)
{
struct rtc_time tm_check;
struct stm_rtc *rtc;
struct resource *res;
int size;
int ret = 0;
rtc = kzalloc(sizeof(struct stm_rtc), GFP_KERNEL);
if (unlikely(!rtc))
return -ENOMEM;
spin_lock_init(&rtc->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (unlikely(res == NULL)) {
dev_err(&pdev->dev, "No IO resource\n");
ret = -ENOENT;
goto err_badres;
}
size = res->end - res->start + 1;
/*
* Memory can not be request because shared between several IPs..
*/
rtc->ioaddr = ioremap(res->start, size);
if (!rtc->ioaddr) {
ret = -EINVAL;
goto err_badres;
}
platform_set_drvdata(pdev, rtc);
device_set_wakeup_capable(&pdev->dev, 1);
rtc->rtc_dev = rtc_device_register(DRV_NAME, &pdev->dev,
&stm_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc_dev)) {
ret = PTR_ERR(rtc->rtc_dev);
goto err_badreg;
}
/*
* 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"
*/
stm_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;
/*
* FIXME:
* the 'tm_check.tm_mday' should be set to zero but the func-
* tions rtc_tm_to_time and rtc_time_to_time aren't coherent.
*/
tm_check.tm_mday = 1;
stm_rtc_set_time(&pdev->dev, &tm_check);
}
return ret;
err_badreg:
iounmap(rtc->ioaddr);
err_badres:
kfree(rtc);
return ret;
}
static int __devexit stm_rtc_remove(struct platform_device *pdev)
{
struct stm_rtc *rtc = platform_get_drvdata(pdev);
if (likely(rtc->rtc_dev))
rtc_device_unregister(rtc->rtc_dev);
iounmap(rtc->ioaddr);
platform_set_drvdata(pdev, NULL);
kfree(rtc);
return 0;
}
static struct platform_driver stm_rtc_platform_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
#ifdef CONFIG_PM
.pm = &stm_rtc_pm_ops,
#endif
},
.probe = stm_rtc_probe,
.remove = __devexit_p(stm_rtc_remove),
};
static int __init stm_rtc_init(void)
{
return platform_driver_register(&stm_rtc_platform_driver);
}
static void __exit stm_rtc_exit(void)
{
platform_driver_unregister(&stm_rtc_platform_driver);
}
module_init(stm_rtc_init);
module_exit(stm_rtc_exit);
MODULE_DESCRIPTION("STMicroelectronics STx5197 RTC driver");
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE("GPL");