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

470 lines
11 KiB
C

/*
* This driver implements a RTC using the Low Power Timer in
* the Low Power Controller (LPC) in some STMicroelectronics devices.
*
* See ADCS 2001950 for more details on the hardware.
*
* Copyright (C) 2009 STMicroelectronics Limited
* Copyright (C) 2010 STMicroelectronics Limited
* Author: Stuart Menefy <stuart.menefy@@st.com>
* 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"
/* 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
/*
* LPC has _only_ one source interrupt therefore the
* periodic-one_shot interrupts are mutually exclusive
*/
#define STM_LPC_MOVE_AVAILABLE 0x0
#define STM_LPC_MODE_PERIODIC 0x1
#define STM_LPC_MODE_ONESHOT 0x2
struct stm_rtc {
struct rtc_device *rtc_dev;
void __iomem *ioaddr;
struct resource *res;
struct clk *clk;
unsigned char mode; /* periodic vs oneshot */
short irq;
int irq_enabled:1;
unsigned long periodic_tick; /* periodic frequency in tick */
spinlock_t lock;
struct rtc_wkalrm alarm;
};
static void stm_rtc_set_hw_alarm(struct stm_rtc *rtc,
unsigned long msb, unsigned long lsb)
{
struct stm_plat_rtc_lpc *pdata =
rtc->rtc_dev->dev.parent->platform_data;
if (pdata->need_wdt_reset)
writel(1, rtc->ioaddr + LPC_WDT_OFF);
writel(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
writel(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
writel(1, rtc->ioaddr + LPC_LPA_START_OFF);
if (pdata->need_wdt_reset)
writel(0, rtc->ioaddr + LPC_WDT_OFF);
}
static irqreturn_t stm_rtc_irq(int this_irq, void *data)
{
struct stm_rtc *rtc = (struct stm_rtc *)data;
spin_lock(&rtc->lock);
switch (rtc->mode) {
case STM_LPC_MODE_PERIODIC:
/* reload the value... */
stm_rtc_set_hw_alarm(rtc, 0, rtc->periodic_tick);
case STM_LPC_MODE_ONESHOT:
rtc_update_irq(rtc->rtc_dev, 1,
(rtc->mode == STM_LPC_MODE_PERIODIC ? RTC_PF : RTC_AF));
break;
default:
break;
}
spin_unlock(&rtc->lock);
return IRQ_HANDLED;
}
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, clk_get_rate(rtc->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;
spin_lock(&rtc->lock);
lpt = (unsigned long long)secs * clk_get_rate(rtc->clk);
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);
spin_unlock(&rtc->lock);
return 0;
}
static int stm_rtc_irq_set_freq(struct device *dev, int freq)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
int ret = 0;
spin_lock(&rtc->lock);
switch (freq) {
case 0:
ret = -EINVAL;
break;
case 1 ... 4096:
rtc->periodic_tick = clk_get_rate(rtc->clk) / freq;
if (!rtc->periodic_tick)
ret = -EINVAL;
break;
default:
ret = -ENOTSUPP;
}
spin_unlock(&rtc->lock);
return ret;
}
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_ioctl(struct device *dev,
unsigned int cmd, unsigned long arg)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
unsigned int ret = 0;
spin_lock(&rtc->lock);
switch (cmd) {
case RTC_AIE_OFF:
case RTC_PIE_OFF:
if ((rtc->mode == STM_LPC_MODE_PERIODIC &&
cmd == RTC_AIE_OFF) ||
(rtc->mode == STM_LPC_MODE_ONESHOT &&
cmd == RTC_PIE_OFF)) {
ret = -EBUSY;
break;
}
if (rtc->irq_enabled)
disable_irq(rtc->irq);
rtc->irq_enabled = 0;
rtc->mode = STM_LPC_MOVE_AVAILABLE;
if (cmd == RTC_AIE_OFF)
device_set_wakeup_enable(dev, 0);
break;
case RTC_AIE_ON:
case RTC_PIE_ON:
if (rtc->mode != STM_LPC_MOVE_AVAILABLE) {
ret = -EBUSY;
break;
}
rtc->mode = (cmd == RTC_PIE_ON ? STM_LPC_MODE_PERIODIC :
STM_LPC_MODE_ONESHOT);
device_set_wakeup_enable(dev, cmd == RTC_PIE_ON ? 0 : 1);
if (cmd == RTC_PIE_ON)
stm_rtc_set_hw_alarm(rtc, 0, rtc->periodic_tick);
if (!rtc->irq_enabled)
enable_irq(rtc->irq);
rtc->irq_enabled = 1;
break;
default:
ret = -ENOIOCTLCMD;
}
spin_unlock(&rtc->lock);
return ret;
}
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;
unsigned long long lpa;
int ret = 0;
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 */
memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
alarm_secs -= now_secs; /* now many secs to fire */
lpa = (unsigned long long)alarm_secs * clk_get_rate(rtc->clk);
spin_lock(&rtc->lock);
stm_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
spin_unlock(&rtc->lock);
if (t->enabled)
ret = stm_rtc_ioctl(dev, RTC_AIE_ON, 0);
return ret;
}
static struct rtc_class_ops stm_rtc_ops = {
.ioctl = stm_rtc_ioctl,
.read_time = stm_rtc_read_time,
.set_time = stm_rtc_set_time,
.read_alarm = stm_rtc_read_alarm,
.set_alarm = stm_rtc_set_alarm,
.irq_set_freq = stm_rtc_irq_set_freq,
};
#ifdef CONFIG_PM
static int stm_rtc_suspend(struct device *dev)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
return 0;
writel(1, rtc->ioaddr + LPC_WDT_OFF);
writel(0, rtc->ioaddr + LPC_LPA_START_OFF);
writel(0, rtc->ioaddr + LPC_WDT_OFF);
return 0;
}
static int stm_rtc_resume(struct device *dev)
{
struct stm_rtc *rtc = dev_get_drvdata(dev);
struct stm_plat_rtc_lpc *pdata = dev->platform_data;
/*
* clean 'rtc->alarm' to allow a new
* a new .set_alarm to the upper RTC layer
*/
memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
if (pdata->need_wdt_reset) {
writel(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
writel(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
writel(1, rtc->ioaddr + LPC_WDT_OFF);
writel(1, rtc->ioaddr + LPC_LPA_START_OFF);
writel(0, rtc->ioaddr + LPC_WDT_OFF);
}
return 0;
}
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 stm_plat_rtc_lpc *plat_data;
struct stm_rtc *rtc;
struct resource *res;
int size;
int ret = 0;
struct rtc_time tm_check;
rtc = kzalloc(sizeof(struct stm_rtc), GFP_KERNEL);
if (unlikely(!rtc))
return -ENOMEM;
spin_lock_init(&rtc->lock);
plat_data = pdev->dev.platform_data;
if (unlikely(plat_data == NULL)) {
dev_err(&pdev->dev, "No platform data\n");
ret = -ENOENT;
goto err_badres;
}
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;
rtc->res = request_mem_region(res->start, size, pdev->name);
if (!rtc->res) {
ret = -EBUSY;
goto err_badres;
}
rtc->ioaddr = ioremap(res->start, size);
if (!rtc->ioaddr) {
ret = -EINVAL;
goto err_badmap;
}
rtc->clk = clk_get(&pdev->dev, plat_data->clk_id);
if (IS_ERR(rtc->clk)) {
pr_err("clk %s not found\n", plat_data->clk_id);
ret = PTR_ERR(rtc->clk);
goto err_badreg;
}
clk_enable(rtc->clk);
pr_debug("%s: is using clk: %s @ %lu\n",
DRV_NAME, rtc->clk->name, clk_get_rate(rtc->clk));
res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!res) {
pr_err("%s Request irq %d not done\n",
__func__, res->start);
return -ENODEV;
}
rtc->irq = res->start;
set_irq_type(rtc->irq, plat_data->irq_edge_level);
enable_irq_wake(rtc->irq);
if (devm_request_irq(&pdev->dev, rtc->irq, stm_rtc_irq,
IRQF_DISABLED, DRV_NAME, rtc) < 0){
pr_err("%s: Request irq not done\n", __func__);
return -ENODEV;
}
disable_irq(rtc->irq);
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;
}
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"
*/
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_badmap:
release_resource(rtc->res);
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);
release_resource(rtc->res);
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 LPC RTC driver");
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("Stuart Menefy <stuart.menefy@st.com>");
MODULE_LICENSE("GPL");