drivers/rtc/rtc-omap.c: unlock and lock rtc registers before and after register writes
RTC module contains a kicker mechanism to prevent any spurious writes from
changing the register values. This mechanism requires two MMR writes to
the KICK0 and KICK1 registers with exact data values before the kicker
lock mechanism is released.
Currently the driver release the lock in the probe and leaves it enabled
until the rtc driver removal. This eliminates the idea of preventing
spurious writes when RTC driver is loaded. So implement rtc lock and
unlock functions before and after register writes.
This is as advised by Paul to implement lock and unlock functions in the
driver and not to unlock and leave it in probe. The same discussion can
be seen here:
http://www.mail-archive.com/linux-omap%40vger.kernel.org/msg111588.html
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index 8e5851a..a5ff009 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -118,12 +118,15 @@
#define KICK0_VALUE 0x83e70b13
#define KICK1_VALUE 0x95a4f1e0
+struct omap_rtc;
+
struct omap_rtc_device_type {
bool has_32kclk_en;
- bool has_kicker;
bool has_irqwakeen;
bool has_pmic_mode;
bool has_power_up_reset;
+ void (*lock)(struct omap_rtc *rtc);
+ void (*unlock)(struct omap_rtc *rtc);
};
struct omap_rtc {
@@ -156,6 +159,26 @@
writel(val, rtc->base + reg);
}
+static void am3352_rtc_unlock(struct omap_rtc *rtc)
+{
+ rtc_writel(rtc, OMAP_RTC_KICK0_REG, KICK0_VALUE);
+ rtc_writel(rtc, OMAP_RTC_KICK1_REG, KICK1_VALUE);
+}
+
+static void am3352_rtc_lock(struct omap_rtc *rtc)
+{
+ rtc_writel(rtc, OMAP_RTC_KICK0_REG, 0);
+ rtc_writel(rtc, OMAP_RTC_KICK1_REG, 0);
+}
+
+static void default_rtc_unlock(struct omap_rtc *rtc)
+{
+}
+
+static void default_rtc_lock(struct omap_rtc *rtc)
+{
+}
+
/*
* We rely on the rtc framework to handle locking (rtc->ops_lock),
* so the only other requirement is that register accesses which
@@ -186,7 +209,9 @@
/* alarm irq? */
if (irq_data & OMAP_RTC_STATUS_ALARM) {
+ rtc->type->unlock(rtc);
rtc_write(rtc, OMAP_RTC_STATUS_REG, OMAP_RTC_STATUS_ALARM);
+ rtc->type->lock(rtc);
events |= RTC_IRQF | RTC_AF;
}
@@ -218,9 +243,11 @@
irqwake_reg &= ~OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
}
rtc_wait_not_busy(rtc);
+ rtc->type->unlock(rtc);
rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, reg);
if (rtc->type->has_irqwakeen)
rtc_write(rtc, OMAP_RTC_IRQWAKEEN, irqwake_reg);
+ rtc->type->lock(rtc);
local_irq_enable();
return 0;
@@ -293,12 +320,14 @@
local_irq_disable();
rtc_wait_not_busy(rtc);
+ rtc->type->unlock(rtc);
rtc_write(rtc, OMAP_RTC_YEARS_REG, tm->tm_year);
rtc_write(rtc, OMAP_RTC_MONTHS_REG, tm->tm_mon);
rtc_write(rtc, OMAP_RTC_DAYS_REG, tm->tm_mday);
rtc_write(rtc, OMAP_RTC_HOURS_REG, tm->tm_hour);
rtc_write(rtc, OMAP_RTC_MINUTES_REG, tm->tm_min);
rtc_write(rtc, OMAP_RTC_SECONDS_REG, tm->tm_sec);
+ rtc->type->lock(rtc);
local_irq_enable();
@@ -341,6 +370,7 @@
local_irq_disable();
rtc_wait_not_busy(rtc);
+ rtc->type->unlock(rtc);
rtc_write(rtc, OMAP_RTC_ALARM_YEARS_REG, alm->time.tm_year);
rtc_write(rtc, OMAP_RTC_ALARM_MONTHS_REG, alm->time.tm_mon);
rtc_write(rtc, OMAP_RTC_ALARM_DAYS_REG, alm->time.tm_mday);
@@ -362,6 +392,7 @@
rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, reg);
if (rtc->type->has_irqwakeen)
rtc_write(rtc, OMAP_RTC_IRQWAKEEN, irqwake_reg);
+ rtc->type->lock(rtc);
local_irq_enable();
@@ -391,6 +422,7 @@
unsigned long now;
u32 val;
+ rtc->type->unlock(rtc);
/* enable pmic_power_en control */
val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
rtc_writel(rtc, OMAP_RTC_PMIC_REG, val | OMAP_RTC_PMIC_POWER_EN_EN);
@@ -423,6 +455,7 @@
val = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
rtc_writel(rtc, OMAP_RTC_INTERRUPTS_REG,
val | OMAP_RTC_INTERRUPTS_IT_ALARM2);
+ rtc->type->lock(rtc);
/*
* Wait for alarm to trigger (within two seconds) and external PMIC to
@@ -442,17 +475,21 @@
static const struct omap_rtc_device_type omap_rtc_default_type = {
.has_power_up_reset = true,
+ .lock = default_rtc_lock,
+ .unlock = default_rtc_unlock,
};
static const struct omap_rtc_device_type omap_rtc_am3352_type = {
.has_32kclk_en = true,
- .has_kicker = true,
.has_irqwakeen = true,
.has_pmic_mode = true,
+ .lock = am3352_rtc_lock,
+ .unlock = am3352_rtc_unlock,
};
static const struct omap_rtc_device_type omap_rtc_da830_type = {
- .has_kicker = true,
+ .lock = am3352_rtc_lock,
+ .unlock = am3352_rtc_unlock,
};
static const struct platform_device_id omap_rtc_id_table[] = {
@@ -527,10 +564,7 @@
pm_runtime_enable(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
- if (rtc->type->has_kicker) {
- rtc_writel(rtc, OMAP_RTC_KICK0_REG, KICK0_VALUE);
- rtc_writel(rtc, OMAP_RTC_KICK1_REG, KICK1_VALUE);
- }
+ rtc->type->unlock(rtc);
/*
* disable interrupts
@@ -593,6 +627,8 @@
if (reg != new_ctrl)
rtc_write(rtc, OMAP_RTC_CTRL_REG, new_ctrl);
+ rtc->type->lock(rtc);
+
device_init_wakeup(&pdev->dev, true);
rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
@@ -626,8 +662,7 @@
err:
device_init_wakeup(&pdev->dev, false);
- if (rtc->type->has_kicker)
- rtc_writel(rtc, OMAP_RTC_KICK0_REG, 0);
+ rtc->type->lock(rtc);
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
@@ -646,11 +681,11 @@
device_init_wakeup(&pdev->dev, 0);
+ rtc->type->unlock(rtc);
/* leave rtc running, but disable irqs */
rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, 0);
- if (rtc->type->has_kicker)
- rtc_writel(rtc, OMAP_RTC_KICK0_REG, 0);
+ rtc->type->lock(rtc);
/* Disable the clock/module */
pm_runtime_put_sync(&pdev->dev);
@@ -666,6 +701,7 @@
rtc->interrupts_reg = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
+ rtc->type->unlock(rtc);
/*
* FIXME: the RTC alarm is not currently acting as a wakeup event
* source on some platforms, and in fact this enable() call is just
@@ -675,6 +711,7 @@
enable_irq_wake(rtc->irq_alarm);
else
rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, 0);
+ rtc->type->lock(rtc);
/* Disable the clock/module */
pm_runtime_put_sync(dev);
@@ -689,10 +726,12 @@
/* Enable the clock/module so that we can access the registers */
pm_runtime_get_sync(dev);
+ rtc->type->unlock(rtc);
if (device_may_wakeup(dev))
disable_irq_wake(rtc->irq_alarm);
else
rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, rtc->interrupts_reg);
+ rtc->type->lock(rtc);
return 0;
}
@@ -709,9 +748,11 @@
* Keep the ALARM interrupt enabled to allow the system to power up on
* alarm events.
*/
+ rtc->type->unlock(rtc);
mask = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
mask &= OMAP_RTC_INTERRUPTS_IT_ALARM;
rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, mask);
+ rtc->type->lock(rtc);
}
static struct platform_driver omap_rtc_driver = {