rtc: rv3028: Add backup switchover mode support

Signed-off-by: Phil Howard <phil@pimoroni.com>

diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index d04c2d4..b69d8e6 100644 (file)
--- 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)) {