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rtc: add STM32 RTC driver

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This patch adds support for the STM32 RTC.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
tirimbino
Amelie Delaunay 8 years ago committed by Alexandre Belloni
parent 7c60930500
commit 4e64350f42
3 changed files with 739 additions and 0 deletions
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  1. 11
      drivers/rtc/Kconfig
  2. 1
      drivers/rtc/Makefile
  3. 727
      drivers/rtc/rtc-stm32.c

11
drivers/rtc/Kconfig
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@ -1716,6 +1716,17 @@ config RTC_DRV_R7301
This driver can also be built as a module. If so, the module
will be called rtc-r7301.
config RTC_DRV_STM32
tristate "STM32 RTC"
select REGMAP_MMIO
depends on ARCH_STM32 || COMPILE_TEST
help
If you say yes here you get support for the STM32 On-Chip
Real Time Clock.
This driver can also be built as a module, if so, the module
will be called "rtc-stm32".
comment "HID Sensor RTC drivers"
config RTC_DRV_HID_SENSOR_TIME

1
drivers/rtc/Makefile
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@ -145,6 +145,7 @@ obj-$(CONFIG_RTC_DRV_SNVS) += rtc-snvs.o
obj-$(CONFIG_RTC_DRV_SPEAR) += rtc-spear.o
obj-$(CONFIG_RTC_DRV_STARFIRE) += rtc-starfire.o
obj-$(CONFIG_RTC_DRV_STK17TA8) += rtc-stk17ta8.o
obj-$(CONFIG_RTC_DRV_STM32) += rtc-stm32.o
obj-$(CONFIG_RTC_DRV_STMP) += rtc-stmp3xxx.o
obj-$(CONFIG_RTC_DRV_ST_LPC) += rtc-st-lpc.o
obj-$(CONFIG_RTC_DRV_SUN4V) += rtc-sun4v.o

727
drivers/rtc/rtc-stm32.c
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@ -0,0 +1,727 @@
/*
* Copyright (C) Amelie Delaunay 2016
* Author: Amelie Delaunay <amelie.delaunay@st.com>
* License terms: GNU General Public License (GPL), version 2
*/
#include <linux/bcd.h>
#include <linux/clk.h>
#include <linux/iopoll.h>
#include <linux/ioport.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#define DRIVER_NAME "stm32_rtc"
/* STM32 RTC registers */
#define STM32_RTC_TR 0x00
#define STM32_RTC_DR 0x04
#define STM32_RTC_CR 0x08
#define STM32_RTC_ISR 0x0C
#define STM32_RTC_PRER 0x10
#define STM32_RTC_ALRMAR 0x1C
#define STM32_RTC_WPR 0x24
/* STM32_RTC_TR bit fields */
#define STM32_RTC_TR_SEC_SHIFT 0
#define STM32_RTC_TR_SEC GENMASK(6, 0)
#define STM32_RTC_TR_MIN_SHIFT 8
#define STM32_RTC_TR_MIN GENMASK(14, 8)
#define STM32_RTC_TR_HOUR_SHIFT 16
#define STM32_RTC_TR_HOUR GENMASK(21, 16)
/* STM32_RTC_DR bit fields */
#define STM32_RTC_DR_DATE_SHIFT 0
#define STM32_RTC_DR_DATE GENMASK(5, 0)
#define STM32_RTC_DR_MONTH_SHIFT 8
#define STM32_RTC_DR_MONTH GENMASK(12, 8)
#define STM32_RTC_DR_WDAY_SHIFT 13
#define STM32_RTC_DR_WDAY GENMASK(15, 13)
#define STM32_RTC_DR_YEAR_SHIFT 16
#define STM32_RTC_DR_YEAR GENMASK(23, 16)
/* STM32_RTC_CR bit fields */
#define STM32_RTC_CR_FMT BIT(6)
#define STM32_RTC_CR_ALRAE BIT(8)
#define STM32_RTC_CR_ALRAIE BIT(12)
/* STM32_RTC_ISR bit fields */
#define STM32_RTC_ISR_ALRAWF BIT(0)
#define STM32_RTC_ISR_INITS BIT(4)
#define STM32_RTC_ISR_RSF BIT(5)
#define STM32_RTC_ISR_INITF BIT(6)
#define STM32_RTC_ISR_INIT BIT(7)
#define STM32_RTC_ISR_ALRAF BIT(8)
/* STM32_RTC_PRER bit fields */
#define STM32_RTC_PRER_PRED_S_SHIFT 0
#define STM32_RTC_PRER_PRED_S GENMASK(14, 0)
#define STM32_RTC_PRER_PRED_A_SHIFT 16
#define STM32_RTC_PRER_PRED_A GENMASK(22, 16)
/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */
#define STM32_RTC_ALRMXR_SEC_SHIFT 0
#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0)
#define STM32_RTC_ALRMXR_SEC_MASK BIT(7)
#define STM32_RTC_ALRMXR_MIN_SHIFT 8
#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8)
#define STM32_RTC_ALRMXR_MIN_MASK BIT(15)
#define STM32_RTC_ALRMXR_HOUR_SHIFT 16
#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16)
#define STM32_RTC_ALRMXR_PM BIT(22)
#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23)
#define STM32_RTC_ALRMXR_DATE_SHIFT 24
#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24)
#define STM32_RTC_ALRMXR_WDSEL BIT(30)
#define STM32_RTC_ALRMXR_WDAY_SHIFT 24
#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24)
#define STM32_RTC_ALRMXR_DATE_MASK BIT(31)
/* STM32_RTC_WPR key constants */
#define RTC_WPR_1ST_KEY 0xCA
#define RTC_WPR_2ND_KEY 0x53
#define RTC_WPR_WRONG_KEY 0xFF
/*
* RTC registers are protected against parasitic write access.
* PWR_CR_DBP bit must be set to enable write access to RTC registers.
*/
/* STM32_PWR_CR */
#define PWR_CR 0x00
/* STM32_PWR_CR bit field */
#define PWR_CR_DBP BIT(8)
struct stm32_rtc {
struct rtc_device *rtc_dev;
void __iomem *base;
struct regmap *dbp;
struct clk *ck_rtc;
int irq_alarm;
};
static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc)
{
writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + STM32_RTC_WPR);
writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + STM32_RTC_WPR);
}
static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
{
writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR);
}
static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
{
unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
if (!(isr & STM32_RTC_ISR_INITF)) {
isr |= STM32_RTC_ISR_INIT;
writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
/*
* It takes around 2 ck_rtc clock cycles to enter in
* initialization phase mode (and have INITF flag set). As
* slowest ck_rtc frequency may be 32kHz and highest should be
* 1MHz, we poll every 10 us with a timeout of 100ms.
*/
return readl_relaxed_poll_timeout_atomic(
rtc->base + STM32_RTC_ISR,
isr, (isr & STM32_RTC_ISR_INITF),
10, 100000);
}
return 0;
}
static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc)
{
unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
isr &= ~STM32_RTC_ISR_INIT;
writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
}
static int stm32_rtc_wait_sync(struct stm32_rtc *rtc)
{
unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
isr &= ~STM32_RTC_ISR_RSF;
writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
/*
* Wait for RSF to be set to ensure the calendar registers are
* synchronised, it takes around 2 ck_rtc clock cycles
*/
return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
isr,
(isr & STM32_RTC_ISR_RSF),
10, 100000);
}
static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id)
{
struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id;
unsigned int isr, cr;
mutex_lock(&rtc->rtc_dev->ops_lock);
isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
cr = readl_relaxed(rtc->base + STM32_RTC_CR);
if ((isr & STM32_RTC_ISR_ALRAF) &&
(cr & STM32_RTC_CR_ALRAIE)) {
/* Alarm A flag - Alarm interrupt */
dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n");
/* Pass event to the kernel */
rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
/* Clear event flag, otherwise new events won't be received */
writel_relaxed(isr & ~STM32_RTC_ISR_ALRAF,
rtc->base + STM32_RTC_ISR);
}
mutex_unlock(&rtc->rtc_dev->ops_lock);
return IRQ_HANDLED;
}
/* Convert rtc_time structure from bin to bcd format */
static void tm2bcd(struct rtc_time *tm)
{
tm->tm_sec = bin2bcd(tm->tm_sec);
tm->tm_min = bin2bcd(tm->tm_min);
tm->tm_hour = bin2bcd(tm->tm_hour);
tm->tm_mday = bin2bcd(tm->tm_mday);
tm->tm_mon = bin2bcd(tm->tm_mon + 1);
tm->tm_year = bin2bcd(tm->tm_year - 100);
/*
* Number of days since Sunday
* - on kernel side, 0=Sunday...6=Saturday
* - on rtc side, 0=invalid,1=Monday...7=Sunday
*/
tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday;
}
/* Convert rtc_time structure from bcd to bin format */
static void bcd2tm(struct rtc_time *tm)
{
tm->tm_sec = bcd2bin(tm->tm_sec);
tm->tm_min = bcd2bin(tm->tm_min);
tm->tm_hour = bcd2bin(tm->tm_hour);
tm->tm_mday = bcd2bin(tm->tm_mday);
tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
tm->tm_year = bcd2bin(tm->tm_year) + 100;
/*
* Number of days since Sunday
* - on kernel side, 0=Sunday...6=Saturday
* - on rtc side, 0=invalid,1=Monday...7=Sunday
*/
tm->tm_wday %= 7;
}
static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
unsigned int tr, dr;
/* Time and Date in BCD format */
tr = readl_relaxed(rtc->base + STM32_RTC_TR);
dr = readl_relaxed(rtc->base + STM32_RTC_DR);
tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT;
/* We don't report tm_yday and tm_isdst */
bcd2tm(tm);
return 0;
}
static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
unsigned int tr, dr;
int ret = 0;
tm2bcd(tm);
/* Time in BCD format */
tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) |
((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) |
((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR);
/* Date in BCD format */
dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) |
((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) |
((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) |
((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY);
stm32_rtc_wpr_unlock(rtc);
ret = stm32_rtc_enter_init_mode(rtc);
if (ret) {
dev_err(dev, "Can't enter in init mode. Set time aborted.\n");
goto end;
}
writel_relaxed(tr, rtc->base + STM32_RTC_TR);
writel_relaxed(dr, rtc->base + STM32_RTC_DR);
stm32_rtc_exit_init_mode(rtc);
ret = stm32_rtc_wait_sync(rtc);
end:
stm32_rtc_wpr_lock(rtc);
return ret;
}
static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
struct rtc_time *tm = &alrm->time;
unsigned int alrmar, cr, isr;
alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR);
cr = readl_relaxed(rtc->base + STM32_RTC_CR);
isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) {
/*
* Date/day doesn't matter in Alarm comparison so alarm
* triggers every day
*/
tm->tm_mday = -1;
tm->tm_wday = -1;
} else {
if (alrmar & STM32_RTC_ALRMXR_WDSEL) {
/* Alarm is set to a day of week */
tm->tm_mday = -1;
tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >>
STM32_RTC_ALRMXR_WDAY_SHIFT;
tm->tm_wday %= 7;
} else {
/* Alarm is set to a day of month */
tm->tm_wday = -1;
tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >>
STM32_RTC_ALRMXR_DATE_SHIFT;
}
}
if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) {
/* Hours don't matter in Alarm comparison */
tm->tm_hour = -1;
} else {
tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >>
STM32_RTC_ALRMXR_HOUR_SHIFT;
if (alrmar & STM32_RTC_ALRMXR_PM)
tm->tm_hour += 12;
}
if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) {
/* Minutes don't matter in Alarm comparison */
tm->tm_min = -1;
} else {
tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >>
STM32_RTC_ALRMXR_MIN_SHIFT;
}
if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) {
/* Seconds don't matter in Alarm comparison */
tm->tm_sec = -1;
} else {
tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >>
STM32_RTC_ALRMXR_SEC_SHIFT;
}
bcd2tm(tm);
alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0;
alrm->pending = (isr & STM32_RTC_ISR_ALRAF) ? 1 : 0;
return 0;
}
static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
unsigned int isr, cr;
cr = readl_relaxed(rtc->base + STM32_RTC_CR);
stm32_rtc_wpr_unlock(rtc);
/* We expose Alarm A to the kernel */
if (enabled)
cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
else
cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
writel_relaxed(cr, rtc->base + STM32_RTC_CR);
/* Clear event flag, otherwise new events won't be received */
isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
isr &= ~STM32_RTC_ISR_ALRAF;
writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
stm32_rtc_wpr_lock(rtc);
return 0;
}
static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm)
{
unsigned int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec;
unsigned int dr = readl_relaxed(rtc->base + STM32_RTC_DR);
unsigned int tr = readl_relaxed(rtc->base + STM32_RTC_TR);
cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
/*
* Assuming current date is M-D-Y H:M:S.
* RTC alarm can't be set on a specific month and year.
* So the valid alarm range is:
* M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S
* with a specific case for December...
*/
if ((((tm->tm_year > cur_year) &&
(tm->tm_mon == 0x1) && (cur_mon == 0x12)) ||
((tm->tm_year == cur_year) &&
(tm->tm_mon <= cur_mon + 1))) &&
((tm->tm_mday > cur_day) ||
((tm->tm_mday == cur_day) &&
((tm->tm_hour > cur_hour) ||
((tm->tm_hour == cur_hour) && (tm->tm_min > cur_min)) ||
((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) &&
(tm->tm_sec >= cur_sec))))))
return 0;
return -EINVAL;
}
static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
struct rtc_time *tm = &alrm->time;
unsigned int cr, isr, alrmar;
int ret = 0;
tm2bcd(tm);
/*
* RTC alarm can't be set on a specific date, unless this date is
* up to the same day of month next month.
*/
if (stm32_rtc_valid_alrm(rtc, tm) < 0) {
dev_err(dev, "Alarm can be set only on upcoming month.\n");
return -EINVAL;
}
alrmar = 0;
/* tm_year and tm_mon are not used because not supported by RTC */
alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) &
STM32_RTC_ALRMXR_DATE;
/* 24-hour format */
alrmar &= ~STM32_RTC_ALRMXR_PM;
alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) &
STM32_RTC_ALRMXR_HOUR;
alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) &
STM32_RTC_ALRMXR_MIN;
alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) &
STM32_RTC_ALRMXR_SEC;
stm32_rtc_wpr_unlock(rtc);
/* Disable Alarm */
cr = readl_relaxed(rtc->base + STM32_RTC_CR);
cr &= ~STM32_RTC_CR_ALRAE;
writel_relaxed(cr, rtc->base + STM32_RTC_CR);
/*
* Poll Alarm write flag to be sure that Alarm update is allowed: it
* takes around 2 ck_rtc clock cycles
*/
ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
isr,
(isr & STM32_RTC_ISR_ALRAWF),
10, 100000);
if (ret) {
dev_err(dev, "Alarm update not allowed\n");
goto end;
}
/* Write to Alarm register */
writel_relaxed(alrmar, rtc->base + STM32_RTC_ALRMAR);
if (alrm->enabled)
stm32_rtc_alarm_irq_enable(dev, 1);
else
stm32_rtc_alarm_irq_enable(dev, 0);
end:
stm32_rtc_wpr_lock(rtc);
return ret;
}
static const struct rtc_class_ops stm32_rtc_ops = {
.read_time = stm32_rtc_read_time,
.set_time = stm32_rtc_set_time,
.read_alarm = stm32_rtc_read_alarm,
.set_alarm = stm32_rtc_set_alarm,
.alarm_irq_enable = stm32_rtc_alarm_irq_enable,
};
#ifdef CONFIG_OF
static const struct of_device_id stm32_rtc_of_match[] = {
{ .compatible = "st,stm32-rtc" },
{}
};
MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
#endif
static int stm32_rtc_init(struct platform_device *pdev,
struct stm32_rtc *rtc)
{
unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
unsigned int rate;
int ret = 0;
rate = clk_get_rate(rtc->ck_rtc);
/* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */
pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT;
for (pred_a = pred_a_max; pred_a >= 0; pred_a--) {
pred_s = (rate / (pred_a + 1)) - 1;
if (((pred_s + 1) * (pred_a + 1)) == rate)
break;
}
/*
* Can't find a 1Hz, so give priority to RTC power consumption
* by choosing the higher possible value for prediv_a
*/
if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) {
pred_a = pred_a_max;
pred_s = (rate / (pred_a + 1)) - 1;
dev_warn(&pdev->dev, "ck_rtc is %s\n",
(rate - ((pred_a + 1) * (pred_s + 1)) < 0) ?
"fast" : "slow");
}
stm32_rtc_wpr_unlock(rtc);
ret = stm32_rtc_enter_init_mode(rtc);
if (ret) {
dev_err(&pdev->dev,
"Can't enter in init mode. Prescaler config failed.\n");
goto end;
}
prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S;
writel_relaxed(prer, rtc->base + STM32_RTC_PRER);
prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A;
writel_relaxed(prer, rtc->base + STM32_RTC_PRER);
/* Force 24h time format */
cr = readl_relaxed(rtc->base + STM32_RTC_CR);
cr &= ~STM32_RTC_CR_FMT;
writel_relaxed(cr, rtc->base + STM32_RTC_CR);
stm32_rtc_exit_init_mode(rtc);
ret = stm32_rtc_wait_sync(rtc);
end:
stm32_rtc_wpr_lock(rtc);
return ret;
}
static int stm32_rtc_probe(struct platform_device *pdev)
{
struct stm32_rtc *rtc;
struct resource *res;
int ret;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rtc->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rtc->base))
return PTR_ERR(rtc->base);
rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
"st,syscfg");
if (IS_ERR(rtc->dbp)) {
dev_err(&pdev->dev, "no st,syscfg\n");
return PTR_ERR(rtc->dbp);
}
rtc->ck_rtc = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(rtc->ck_rtc)) {
dev_err(&pdev->dev, "no ck_rtc clock");
return PTR_ERR(rtc->ck_rtc);
}
ret = clk_prepare_enable(rtc->ck_rtc);
if (ret)
return ret;
regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, PWR_CR_DBP);
/*
* After a system reset, RTC_ISR.INITS flag can be read to check if
* the calendar has been initalized or not. INITS flag is reset by a
* power-on reset (no vbat, no power-supply). It is not reset if
* ck_rtc parent clock has changed (so RTC prescalers need to be
* changed). That's why we cannot rely on this flag to know if RTC
* init has to be done.
*/
ret = stm32_rtc_init(pdev, rtc);
if (ret)
goto err;
rtc->irq_alarm = platform_get_irq(pdev, 0);
if (rtc->irq_alarm <= 0) {
dev_err(&pdev->dev, "no alarm irq\n");
ret = rtc->irq_alarm;
goto err;
}
platform_set_drvdata(pdev, rtc);
ret = device_init_wakeup(&pdev->dev, true);
if (ret)
dev_warn(&pdev->dev,
"alarm won't be able to wake up the system");
rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
&stm32_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc_dev)) {
ret = PTR_ERR(rtc->rtc_dev);
dev_err(&pdev->dev, "rtc device registration failed, err=%d\n",
ret);
goto err;
}
/* Handle RTC alarm interrupts */
ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL,
stm32_rtc_alarm_irq,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
pdev->name, rtc);
if (ret) {
dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n",
rtc->irq_alarm);
goto err;
}
/*
* If INITS flag is reset (calendar year field set to 0x00), calendar
* must be initialized
*/
if (!(readl_relaxed(rtc->base + STM32_RTC_ISR) & STM32_RTC_ISR_INITS))
dev_warn(&pdev->dev, "Date/Time must be initialized\n");
return 0;
err:
clk_disable_unprepare(rtc->ck_rtc);
regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP);
device_init_wakeup(&pdev->dev, false);
return ret;
}
static int __exit stm32_rtc_remove(struct platform_device *pdev)
{
struct stm32_rtc *rtc = platform_get_drvdata(pdev);
unsigned int cr;
/* Disable interrupts */
stm32_rtc_wpr_unlock(rtc);
cr = readl_relaxed(rtc->base + STM32_RTC_CR);
cr &= ~STM32_RTC_CR_ALRAIE;
writel_relaxed(cr, rtc->base + STM32_RTC_CR);
stm32_rtc_wpr_lock(rtc);
clk_disable_unprepare(rtc->ck_rtc);
/* Enable backup domain write protection */
regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP);
device_init_wakeup(&pdev->dev, false);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int stm32_rtc_suspend(struct device *dev)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
return enable_irq_wake(rtc->irq_alarm);
return 0;
}
static int stm32_rtc_resume(struct device *dev)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
int ret = 0;
ret = stm32_rtc_wait_sync(rtc);
if (ret < 0)
return ret;
if (device_may_wakeup(dev))
return disable_irq_wake(rtc->irq_alarm);
return ret;
}
#endif
static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops,
stm32_rtc_suspend, stm32_rtc_resume);
static struct platform_driver stm32_rtc_driver = {
.probe = stm32_rtc_probe,
.remove = stm32_rtc_remove,
.driver = {
.name = DRIVER_NAME,
.pm = &stm32_rtc_pm_ops,
.of_match_table = stm32_rtc_of_match,
},
};
module_platform_driver(stm32_rtc_driver);
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
MODULE_LICENSE("GPL v2");
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