Adds support for the backup switchover mode register in the rv3028
RTC. This allows the clock to automatically switch over to a backup
power supply when the main power supply is lost.
>From 7ee04005288f0543debe46ed918b77374ad63adf Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@xxxxxxxxxxxxx>
Date: Fri, 29 Mar 2019 10:53:14 +0000
Subject: [PATCH 1/3] rtc: rv3028: Add backup switchover mode support
Signed-off-by: Phil Howard <phil@xxxxxxxxxxxx>
---
drivers/rtc/rtc-rv3028.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index d04c2d4816555..b69d8e6408aae 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -74,6 +74,7 @@
#define RV3028_BACKUP_TCE BIT(5)
#define RV3028_BACKUP_TCR_MASK GENMASK(1,0)
+#define RV3028_BACKUP_BSM_MASK 0x0C
#define OFFSET_STEP_PPT 953674
@@ -601,6 +602,7 @@ static int rv3028_probe(struct i2c_client *client)
struct rv3028_data *rv3028;
int ret, status;
u32 ohms;
+ u8 bsm;
struct nvmem_config nvmem_cfg = {
.name = "rv3028_nvram",
.word_size = 1,
@@ -671,6 +673,21 @@ static int rv3028_probe(struct i2c_client *client)
if (ret)
return ret;
+ /* setup backup switchover mode */
+ if (!device_property_read_u8(&client->dev, "backup-switchover-mode",
+ &bsm)) {
+ if (bsm <= 3) {
+ ret = regmap_update_bits(rv3028->regmap, RV3028_BACKUP,
+ RV3028_BACKUP_BSM_MASK,
+ (bsm & 0x03) << 2);
+
+ if (ret)
+ return ret;
+ } else {
+ dev_warn(&client->dev, "invalid backup switchover mode value\n");
+ }
+ }
+
/* setup trickle charger */
if (!device_property_read_u32(&client->dev, "trickle-resistor-ohms",
&ohms)) {
>From ae9228b10d864368b934839156b6d9fa58fb5724 Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@xxxxxxxxxxxxx>
Date: Fri, 29 Mar 2019 10:57:07 +0000
Subject: [PATCH 2/3] dt-bindings: rv3028 backup switchover support
Signed-off-by: Phil Howard <phil@xxxxxxxxxxxx>
---
Documentation/devicetree/bindings/rtc/rtc.txt | 1 +
1 file changed, 1 insertion(+)
diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt
b/Documentation/devicetree/bindings/rtc/rtc.txt
index 3e6a215e7304b..33fcad8754ec2 100644
--- a/Documentation/devicetree/bindings/rtc/rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc.txt
@@ -26,6 +26,7 @@ below.
- trickle-diode-disable : Do not use internal trickle charger diode Should be
given if internal trickle charger diode should be
disabled
+- backup-switchover-mode : Configure RTC backup power supply switch behaviour
- wakeup-source : Enables wake up of host system on alarm
- quartz-load-femtofarads : The capacitive load of the quartz(x-tal),
expressed in femto Farad (fF).
--
--
Philip Howard
Maker, Pimoroni Ltd.
phil@xxxxxxxxxxxx
http://pimoroni.com
@pimoroni
