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Date: Tue, 3 Jan 2017 09:42:30 +0100
From: Amelie DELAUNAY <amelie.delaunay@...com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>
CC: Alessandro Zummo <a.zummo@...ertech.it>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre TORGUE <alexandre.torgue@...com>,
Russell King <linux@...linux.org.uk>,
"rtc-linux@...glegroups.com" <rtc-linux@...glegroups.com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Gabriel FERNANDEZ <gabriel.fernandez@...com>
Subject: Re: [PATCHv2 3/8] rtc: add STM32 RTC driver
Hi Mathieu,
Thanks for reviewing,
On 12/16/2016 08:08 PM, Mathieu Poirier wrote:
> On Fri, Dec 16, 2016 at 09:50:52AM +0100, Amelie Delaunay wrote:
>> This patch adds support for the STM32 RTC.
>>
>> Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
>> ---
>> drivers/rtc/Kconfig | 11 +
>> drivers/rtc/Makefile | 1 +
>> drivers/rtc/rtc-stm32.c | 776 ++++++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 788 insertions(+)
>> create mode 100644 drivers/rtc/rtc-stm32.c
>>
>> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
>> index e859d14..11eb28a 100644
>> --- a/drivers/rtc/Kconfig
>> +++ b/drivers/rtc/Kconfig
>> @@ -1706,6 +1706,17 @@ config RTC_DRV_PIC32
>> This driver can also be built as a module. If so, the module
>> will be called rtc-pic32
>>
>> +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
>> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
>> index 1ac694a..87bd9cc 100644
>> --- a/drivers/rtc/Makefile
>> +++ b/drivers/rtc/Makefile
>> @@ -144,6 +144,7 @@ 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
>> diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
>> new file mode 100644
>> index 0000000..6ce0f5a
>> --- /dev/null
>> +++ b/drivers/rtc/rtc-stm32.c
>> @@ -0,0 +1,776 @@
>> +/*
>> + * Copyright (C) Amelie Delaunay 2016
>> + * Author: Amelie Delaunay <amelie.delaunay@...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>
>> +#include <linux/spinlock.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 agains 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)
>> +
>> +static struct regmap *dbp;
>> +
>> +struct stm32_rtc {
>> + struct rtc_device *rtc_dev;
>> + void __iomem *base;
>> + struct clk *ck_rtc;
>> + spinlock_t lock; /* Protects registers accesses */
>> + 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;
>> + unsigned long irqflags;
>> +
>> + spin_lock_irqsave(&rtc->lock, irqflags);
>> +
>> + /* Time and Date in BCD format */
>> + tr = readl_relaxed(rtc->base + STM32_RTC_TR);
>> + dr = readl_relaxed(rtc->base + STM32_RTC_DR);
>> +
>> + spin_unlock_irqrestore(&rtc->lock, irqflags);
>> +
>> + 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);
>> +
>> + if (rtc_valid_tm(tm) < 0) {
>> + dev_err(dev, "%s: rtc_time is not valid.\n", __func__);
>> + return -EINVAL;
>> + }
>> +
>> + 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;
>> + unsigned long irqflags;
>> + int ret = 0;
>> +
>> + if (rtc_valid_tm(tm) < 0) {
>> + dev_err(dev, "%s: rtc_time is not valid.\n", __func__);
>> + return -EINVAL;
>> + }
>> +
>> + 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);
>> +
>> + spin_lock_irqsave(&rtc->lock, irqflags);
>> +
>> + 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);
>> +
>> + spin_unlock_irqrestore(&rtc->lock, irqflags);
>> +
>> + 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;
>> + unsigned long irqflags;
>> +
>> + spin_lock_irqsave(&rtc->lock, irqflags);
>> +
>> + alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR);
>> + cr = readl_relaxed(rtc->base + STM32_RTC_CR);
>> + isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
>> +
>> + spin_unlock_irqrestore(&rtc->lock, irqflags);
>> +
>> + 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 long irqflags;
>> + unsigned int isr, cr;
>> +
>> + spin_lock_irqsave(&rtc->lock, irqflags);
>> +
>> + 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 irqflags, 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);
>> +
>> + spin_unlock_irqrestore(&rtc->lock, irqflags);
>> +
>> + 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 long irqflags;
>> + unsigned int cr, isr, alrmar;
>> + int ret = 0;
>> +
>> + if (rtc_valid_tm(tm)) {
>> + dev_err(dev, "Alarm time not valid.\n");
>> + return -EINVAL;
>> + }
>> +
>> + 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;
>> + }
>> +
>> + spin_lock_irqsave(&rtc->lock, irqflags);
>> +
>> + 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;
>> + }
>> +
>> + 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;
>
> All this work on alrmar is done while the spinlock is held. If I'm not
> mistaking nothing prevents you from doing that processing before taking the
> spinlock.
>
Yes, I'll move alrmar processing above, just before taking the spinlock.
>> +
>> + /* 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);
>> +
>> + spin_unlock_irqrestore(&rtc->lock, irqflags);
>> +
>> + 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;
>> + unsigned long irqflags;
>> + 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");
>> + }
>> +
>> + spin_lock_irqsave(&rtc->lock, irqflags);
>> +
>> + 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);
>> +
>> + spin_unlock_irqrestore(&rtc->lock, irqflags);
>> +
>> + 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);
>> +
>> + dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "st,syscfg");
>> + if (IS_ERR(dbp)) {
>> + dev_err(&pdev->dev, "no st,syscfg\n");
>> + return PTR_ERR(dbp);
>> + }
>> +
>> + spin_lock_init(&rtc->lock);
>> +
>> + 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(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 = -ENOENT;
>
> Function platform_get_irq() returns a wealth of error codes that are lost here.
> Doing 'ret = rtc->irq_alarm;' would prevent that from happening.
>
OK
>> + 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(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(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@...com>");
>> +MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 1.9.1
>>
Happy New Year!
Amelie
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