[PATCH 1/3] rtc: stm32: rework register management to prepare other version of RTC

From: Amelie Delaunay
Date: Thu Apr 19 2018 - 09:35:45 EST

This patch reworks register/bits management because next version of RTC
uses the same way of working but with different register's offset or bits
moved in new registers.

Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
---
drivers/rtc/rtc-stm32.c | 188 +++++++++++++++++++++++++++++++++---------------
1 file changed, 129 insertions(+), 59 deletions(-)

diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index de49b5b..52ee027 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -16,15 +16,6 @@

#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)
@@ -85,7 +76,26 @@
#define RTC_WPR_2ND_KEY 0x53
#define RTC_WPR_WRONG_KEY 0xFF

+struct stm32_rtc;
+
+struct stm32_rtc_registers {
+ u8 tr;
+ u8 dr;
+ u8 cr;
+ u8 isr;
+ u8 prer;
+ u8 alrmar;
+ u8 wpr;
+};
+
+struct stm32_rtc_events {
+ u32 alra;
+};
+
struct stm32_rtc_data {
+ const struct stm32_rtc_registers regs;
+ const struct stm32_rtc_events events;
+ void (*clear_events)(struct stm32_rtc *rtc, unsigned int flags);
bool has_pclk;
bool need_dbp;
};
@@ -96,30 +106,35 @@ struct stm32_rtc {
struct regmap *dbp;
unsigned int dbp_reg;
unsigned int dbp_mask;
- struct stm32_rtc_data *data;
struct clk *pclk;
struct clk *rtc_ck;
+ const struct stm32_rtc_data *data;
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);
+ struct stm32_rtc_registers regs = rtc->data->regs;
+
+ writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + regs.wpr);
+ writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + regs.wpr);
}

static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
{
- writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR);
+ struct stm32_rtc_registers regs = rtc->data->regs;
+
+ writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + regs.wpr);
}

static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
{
- unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
+ struct stm32_rtc_registers regs = rtc->data->regs;
+ unsigned int isr = readl_relaxed(rtc->base + regs.isr);

if (!(isr & STM32_RTC_ISR_INITF)) {
isr |= STM32_RTC_ISR_INIT;
- writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
+ writel_relaxed(isr, rtc->base + regs.isr);

/*
* It takes around 2 rtc_ck clock cycles to enter in
@@ -128,7 +143,7 @@ static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
* 1MHz, we poll every 10 us with a timeout of 100ms.
*/
return readl_relaxed_poll_timeout_atomic(
- rtc->base + STM32_RTC_ISR,
+ rtc->base + regs.isr,
isr, (isr & STM32_RTC_ISR_INITF),
10, 100000);
}
@@ -138,40 +153,50 @@ static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)

static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc)
{
- unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
+ struct stm32_rtc_registers regs = rtc->data->regs;
+ unsigned int isr = readl_relaxed(rtc->base + regs.isr);

isr &= ~STM32_RTC_ISR_INIT;
- writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
+ writel_relaxed(isr, rtc->base + regs.isr);
}

static int stm32_rtc_wait_sync(struct stm32_rtc *rtc)
{
- unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
+ struct stm32_rtc_registers regs = rtc->data->regs;
+ unsigned int isr = readl_relaxed(rtc->base + regs.isr);

isr &= ~STM32_RTC_ISR_RSF;
- writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
+ writel_relaxed(isr, rtc->base + regs.isr);

/*
* Wait for RSF to be set to ensure the calendar registers are
* synchronised, it takes around 2 rtc_ck clock cycles
*/
- return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
+ return readl_relaxed_poll_timeout_atomic(rtc->base + regs.isr,
isr,
(isr & STM32_RTC_ISR_RSF),
10, 100000);
}

+static void stm32_rtc_clear_event_flags(struct stm32_rtc *rtc,
+ unsigned int flags)
+{
+ rtc->data->clear_events(rtc, flags);
+}
+
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;
+ struct stm32_rtc_registers regs = rtc->data->regs;
+ struct stm32_rtc_events evts = rtc->data->events;
+ unsigned int status, cr;

mutex_lock(&rtc->rtc_dev->ops_lock);

- isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
- cr = readl_relaxed(rtc->base + STM32_RTC_CR);
+ status = readl_relaxed(rtc->base + regs.isr);
+ cr = readl_relaxed(rtc->base + regs.cr);

- if ((isr & STM32_RTC_ISR_ALRAF) &&
+ if ((status & evts.alra) &&
(cr & STM32_RTC_CR_ALRAIE)) {
/* Alarm A flag - Alarm interrupt */
dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n");
@@ -179,9 +204,8 @@ static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id)
/* 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);
+ /* Clear event flags, otherwise new events won't be received */
+ stm32_rtc_clear_event_flags(rtc, evts.alra);
}

mutex_unlock(&rtc->rtc_dev->ops_lock);
@@ -228,11 +252,12 @@ static void bcd2tm(struct rtc_time *tm)
static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
+ struct stm32_rtc_registers regs = rtc->data->regs;
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);
+ tr = readl_relaxed(rtc->base + regs.tr);
+ dr = readl_relaxed(rtc->base + regs.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;
@@ -253,6 +278,7 @@ static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm)
static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
+ struct stm32_rtc_registers regs = rtc->data->regs;
unsigned int tr, dr;
int ret = 0;

@@ -277,8 +303,8 @@ static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
goto end;
}

- writel_relaxed(tr, rtc->base + STM32_RTC_TR);
- writel_relaxed(dr, rtc->base + STM32_RTC_DR);
+ writel_relaxed(tr, rtc->base + regs.tr);
+ writel_relaxed(dr, rtc->base + regs.dr);

stm32_rtc_exit_init_mode(rtc);

@@ -292,12 +318,14 @@ static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
+ struct stm32_rtc_registers regs = rtc->data->regs;
+ struct stm32_rtc_events evts = rtc->data->events;
struct rtc_time *tm = &alrm->time;
- unsigned int alrmar, cr, isr;
+ unsigned int alrmar, cr, status;

- alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR);
- cr = readl_relaxed(rtc->base + STM32_RTC_CR);
- isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
+ alrmar = readl_relaxed(rtc->base + regs.alrmar);
+ cr = readl_relaxed(rtc->base + regs.cr);
+ status = readl_relaxed(rtc->base + regs.isr);

if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) {
/*
@@ -350,7 +378,7 @@ static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
bcd2tm(tm);

alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0;
- alrm->pending = (isr & STM32_RTC_ISR_ALRAF) ? 1 : 0;
+ alrm->pending = (status & evts.alra) ? 1 : 0;

return 0;
}
@@ -358,9 +386,11 @@ static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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;
+ struct stm32_rtc_registers regs = rtc->data->regs;
+ struct stm32_rtc_events evts = rtc->data->events;
+ unsigned int cr;

- cr = readl_relaxed(rtc->base + STM32_RTC_CR);
+ cr = readl_relaxed(rtc->base + regs.cr);

stm32_rtc_wpr_unlock(rtc);

@@ -369,12 +399,10 @@ static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int 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);
+ writel_relaxed(cr, rtc->base + regs.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);
+ /* Clear event flags, otherwise new events won't be received */
+ stm32_rtc_clear_event_flags(rtc, evts.alra);

stm32_rtc_wpr_lock(rtc);

@@ -383,9 +411,10 @@ static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)

static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm)
{
+ struct stm32_rtc_registers regs = rtc->data->regs;
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);
+ unsigned int dr = readl_relaxed(rtc->base + regs.dr);
+ unsigned int tr = readl_relaxed(rtc->base + regs.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;
@@ -419,6 +448,7 @@ static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm)
static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct stm32_rtc *rtc = dev_get_drvdata(dev);
+ struct stm32_rtc_registers regs = rtc->data->regs;
struct rtc_time *tm = &alrm->time;
unsigned int cr, isr, alrmar;
int ret = 0;
@@ -450,15 +480,15 @@ static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
stm32_rtc_wpr_unlock(rtc);

/* Disable Alarm */
- cr = readl_relaxed(rtc->base + STM32_RTC_CR);
+ cr = readl_relaxed(rtc->base + regs.cr);
cr &= ~STM32_RTC_CR_ALRAE;
- writel_relaxed(cr, rtc->base + STM32_RTC_CR);
+ writel_relaxed(cr, rtc->base + regs.cr);

/*
* Poll Alarm write flag to be sure that Alarm update is allowed: it
* takes around 2 rtc_ck clock cycles
*/
- ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
+ ret = readl_relaxed_poll_timeout_atomic(rtc->base + regs.isr,
isr,
(isr & STM32_RTC_ISR_ALRAWF),
10, 100000);
@@ -469,7 +499,7 @@ static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
}

/* Write to Alarm register */
- writel_relaxed(alrmar, rtc->base + STM32_RTC_ALRMAR);
+ writel_relaxed(alrmar, rtc->base + regs.alrmar);

if (alrm->enabled)
stm32_rtc_alarm_irq_enable(dev, 1);
@@ -490,14 +520,50 @@ static const struct rtc_class_ops stm32_rtc_ops = {
.alarm_irq_enable = stm32_rtc_alarm_irq_enable,
};

+static void stm32_rtc_clear_events(struct stm32_rtc *rtc,
+ unsigned int flags)
+{
+ struct stm32_rtc_registers regs = rtc->data->regs;
+
+ /* Flags are cleared by writing 0 in RTC_ISR */
+ writel_relaxed(readl_relaxed(rtc->base + regs.isr) & ~flags,
+ rtc->base + regs.isr);
+}
+
static const struct stm32_rtc_data stm32_rtc_data = {
.has_pclk = false,
.need_dbp = true,
+ .regs = {
+ .tr = 0x00,
+ .dr = 0x04,
+ .cr = 0x08,
+ .isr = 0x0C,
+ .prer = 0x10,
+ .alrmar = 0x1C,
+ .wpr = 0x24,
+ },
+ .events = {
+ .alra = STM32_RTC_ISR_ALRAF,
+ },
+ .clear_events = stm32_rtc_clear_events,
};

static const struct stm32_rtc_data stm32h7_rtc_data = {
.has_pclk = true,
.need_dbp = true,
+ .regs = {
+ .tr = 0x00,
+ .dr = 0x04,
+ .cr = 0x08,
+ .isr = 0x0C,
+ .prer = 0x10,
+ .alrmar = 0x1C,
+ .wpr = 0x24,
+ },
+ .events = {
+ .alra = STM32_RTC_ISR_ALRAF,
+ },
+ .clear_events = stm32_rtc_clear_events,
};

static const struct of_device_id stm32_rtc_of_match[] = {
@@ -510,6 +576,7 @@ MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
static int stm32_rtc_init(struct platform_device *pdev,
struct stm32_rtc *rtc)
{
+ struct stm32_rtc_registers regs = rtc->data->regs;
unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
unsigned int rate;
int ret = 0;
@@ -550,14 +617,14 @@ static int stm32_rtc_init(struct platform_device *pdev,
}

prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S;
- writel_relaxed(prer, rtc->base + STM32_RTC_PRER);
+ writel_relaxed(prer, rtc->base + regs.prer);
prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A;
- writel_relaxed(prer, rtc->base + STM32_RTC_PRER);
+ writel_relaxed(prer, rtc->base + regs.prer);

/* Force 24h time format */
- cr = readl_relaxed(rtc->base + STM32_RTC_CR);
+ cr = readl_relaxed(rtc->base + regs.cr);
cr &= ~STM32_RTC_CR_FMT;
- writel_relaxed(cr, rtc->base + STM32_RTC_CR);
+ writel_relaxed(cr, rtc->base + regs.cr);

stm32_rtc_exit_init_mode(rtc);

@@ -571,6 +638,7 @@ static int stm32_rtc_init(struct platform_device *pdev,
static int stm32_rtc_probe(struct platform_device *pdev)
{
struct stm32_rtc *rtc;
+ struct stm32_rtc_registers regs;
struct resource *res;
int ret;

@@ -585,6 +653,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)

rtc->data = (struct stm32_rtc_data *)
of_device_get_match_data(&pdev->dev);
+ regs = rtc->data->regs;

if (rtc->data->need_dbp) {
rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
@@ -641,7 +710,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)

/*
* 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
+ * the calendar has been initialized or not. INITS flag is reset by a
* power-on reset (no vbat, no power-supply). It is not reset if
* rtc_ck parent clock has changed (so RTC prescalers need to be
* changed). That's why we cannot rely on this flag to know if RTC
@@ -666,7 +735,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)
"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);
+ &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",
@@ -688,7 +757,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)
* 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))
+ if (!(readl_relaxed(rtc->base + regs.isr) & STM32_RTC_ISR_INITS))
dev_warn(&pdev->dev, "Date/Time must be initialized\n");

return 0;
@@ -708,13 +777,14 @@ static int stm32_rtc_probe(struct platform_device *pdev)
static int stm32_rtc_remove(struct platform_device *pdev)
{
struct stm32_rtc *rtc = platform_get_drvdata(pdev);
+ struct stm32_rtc_registers regs = rtc->data->regs;
unsigned int cr;

/* Disable interrupts */
stm32_rtc_wpr_unlock(rtc);
- cr = readl_relaxed(rtc->base + STM32_RTC_CR);
+ cr = readl_relaxed(rtc->base + regs.cr);
cr &= ~STM32_RTC_CR_ALRAIE;
- writel_relaxed(cr, rtc->base + STM32_RTC_CR);
+ writel_relaxed(cr, rtc->base + regs.cr);
stm32_rtc_wpr_lock(rtc);

clk_disable_unprepare(rtc->rtc_ck);
--
2.7.4