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Message-ID: <1465968641-8080-1-git-send-email-j-keerthy@ti.com>
Date: Wed, 15 Jun 2016 11:00:41 +0530
From: Keerthy <j-keerthy@...com>
To: <alexandre.belloni@...e-electrons.com>, <a.zummo@...ertech.it>
CC: <rtc-linux@...glegroups.com>, <j-keerthy@...com>,
<Russ.Dill@...com>, <linux-omap@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH] RTC: Add functionality to read/write rtc scratch registers
From: Russ Dill <Russ.Dill@...com>
Many RTCs provide scratch registers that are maintained so long as the RTC
has power. Provide a generic method to access these registers.
Signed-off-by: Russ Dill <Russ.Dill@...com>
Signed-off-by: Keerthy <j-keerthy@...com>
---
drivers/rtc/interface.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
drivers/rtc/rtc-omap.c | 35 ++++++++++++++++++++++++++++++++++
include/linux/rtc.h | 7 +++++++
3 files changed, 92 insertions(+)
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 7cafd4d..d5a7ee2 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -1018,3 +1018,53 @@ int rtc_set_offset(struct rtc_device *rtc, long offset)
mutex_unlock(&rtc->ops_lock);
return ret;
}
+
+/* rtc_read_scratch - Read from RTC scratch register
+ * @ rtc: rtc device to be used
+ * @ index: index of scratch register
+ * @ value: returned value read
+ *
+ * Kernel interface read from an RTC scratch register
+ */
+int rtc_read_scratch(struct rtc_device *rtc, unsigned int index, u32 *value)
+{
+ int err;
+
+ mutex_lock(&rtc->ops_lock);
+ if (!rtc->ops)
+ err = -ENODEV;
+ else if (index >= rtc->ops->scratch_size || !rtc->ops->read_scratch)
+ err = -EINVAL;
+ else
+ err = rtc->ops->read_scratch(rtc->dev.parent, index, value);
+ mutex_unlock(&rtc->ops_lock);
+ return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_scratch);
+
+/* rtc_write_scratch - Write to RTC scratch register
+ * @ rtc: rtc device to be used
+ * @ index: index of scratch register
+ * @ value: value to write
+ *
+ * Kernel interface write to an RTC scratch register
+ */
+int rtc_write_scratch(struct rtc_device *rtc, unsigned int index, u32 value)
+{
+ int err;
+
+ mutex_lock(&rtc->ops_lock);
+
+ if (!rtc->ops)
+ err = -ENODEV;
+ else if (index >= rtc->ops->scratch_size ||
+ !rtc->ops->write_scratch)
+ err = -EINVAL;
+ else
+ err = rtc->ops->write_scratch(rtc->dev.parent, index, value);
+
+ mutex_unlock(&rtc->ops_lock);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(rtc_write_scratch);
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index ec2e9c5..d00ca11 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -66,6 +66,10 @@
#define OMAP_RTC_COMP_MSB_REG 0x50
#define OMAP_RTC_OSC_REG 0x54
+#define OMAP_RTC_SCRATCH0_REG 0x60
+#define OMAP_RTC_SCRATCH1_REG 0x64
+#define OMAP_RTC_SCRATCH2_REG 0x68
+
#define OMAP_RTC_KICK0_REG 0x6c
#define OMAP_RTC_KICK1_REG 0x70
@@ -405,6 +409,34 @@ static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
static struct omap_rtc *omap_rtc_power_off_rtc;
+static const u32 omap_rtc_scratch_regs[] = {
+ OMAP_RTC_SCRATCH0_REG,
+ OMAP_RTC_SCRATCH1_REG,
+ OMAP_RTC_SCRATCH2_REG,
+};
+
+static int omap_rtc_read_scratch(struct device *dev, unsigned int index,
+ u32 *value)
+{
+ *value = readl(omap_rtc_power_off_rtc->base +
+ omap_rtc_scratch_regs[index]);
+
+ return 0;
+}
+
+static int omap_rtc_write_scratch(struct device *dev, unsigned int index,
+ u32 value)
+{
+ struct omap_rtc *rtc = dev_get_drvdata(dev);
+
+ rtc->type->unlock(rtc);
+ writel(value, omap_rtc_power_off_rtc->base +
+ omap_rtc_scratch_regs[index]);
+ rtc->type->lock(rtc);
+
+ return 0;
+}
+
/*
* omap_rtc_poweroff: RTC-controlled power off
*
@@ -475,6 +507,9 @@ static struct rtc_class_ops omap_rtc_ops = {
.read_alarm = omap_rtc_read_alarm,
.set_alarm = omap_rtc_set_alarm,
.alarm_irq_enable = omap_rtc_alarm_irq_enable,
+ .read_scratch = omap_rtc_read_scratch,
+ .write_scratch = omap_rtc_write_scratch,
+ .scratch_size = ARRAY_SIZE(omap_rtc_scratch_regs),
};
static const struct omap_rtc_device_type omap_rtc_default_type = {
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index b693ada..da5e003 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -91,6 +91,10 @@ struct rtc_class_ops {
int (*alarm_irq_enable)(struct device *, unsigned int enabled);
int (*read_offset)(struct device *, long *offset);
int (*set_offset)(struct device *, long offset);
+ int (*read_scratch)(struct device *, unsigned int, u32*);
+ int (*write_scratch)(struct device *, unsigned int, u32);
+
+ unsigned int scratch_size;
};
#define RTC_DEVICE_NAME_SIZE 20
@@ -214,6 +218,9 @@ int rtc_read_offset(struct rtc_device *rtc, long *offset);
int rtc_set_offset(struct rtc_device *rtc, long offset);
void rtc_timer_do_work(struct work_struct *work);
+int rtc_read_scratch(struct rtc_device *rtc, unsigned int index, u32 *value);
+int rtc_write_scratch(struct rtc_device *rtc, unsigned int index, u32 value);
+
static inline bool is_leap_year(unsigned int year)
{
return (!(year % 4) && (year % 100)) || !(year % 400);
--
1.9.1
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