Property "trickle-resistor-ohms" allows us to set trickle charger
resistor. However there is no possibility to disable it afterwards.
>From now on, disable trickle charger circuit in case device-tree
property "trickle-resistor-ohms" is set to -1.
Additionally, lets make sure we only update internal EEPROM in case of a
change. This prevents wear due to excessive EEPROM writes on each probe.
Signed-off-by: Andrej Picej <andrej.picej@xxxxxxxxx>
---
Changes in v2:
- disable trickle charger if device tree property trickle-resistor-ohms
is set to -1.
---
drivers/rtc/rtc-rv3028.c | 45 +++++++++++++++++++++++++++++-----------
1 file changed, 33 insertions(+), 12 deletions(-)
diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index ec5d7a614e2d..da2ae81fe7c8 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -859,7 +859,8 @@ static int rv3028_probe(struct i2c_client *client)
{
struct rv3028_data *rv3028;
int ret, status;
- u32 ohms;
+ s32 ohms;
+ int val_old, val;
struct nvmem_config nvmem_cfg = {
.name = "rv3028_nvram",
.word_size = 1,
@@ -937,22 +938,42 @@ static int rv3028_probe(struct i2c_client *client)
if (ret)
return ret;
- /* setup trickle charger */
- if (!device_property_read_u32(&client->dev, "trickle-resistor-ohms",
- &ohms)) {
- int i;
+ ret = regmap_read(rv3028->regmap, RV3028_BACKUP, &val_old);
+ if (ret < 0)
+ return ret;
+
+ /* mask out only trickle charger bits */
+ val_old = val_old & (RV3028_BACKUP_TCE | RV3028_BACKUP_TCR_MASK);
- for (i = 0; i < ARRAY_SIZE(rv3028_trickle_resistors); i++)
- if (ohms == rv3028_trickle_resistors[i])
- break;
+ /* setup trickle charger */
+ if (!of_property_read_s32(client->dev.of_node, "trickle-resistor-ohms",
+ &ohms)) {
+ /* disable trickle charger if trickle-resistor-ohms = <(-1)>; */
+ if (ohms == -1) {
+ val = val_old & ~RV3028_BACKUP_TCE;
+ } else {
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(rv3028_trickle_resistors); i++)
+ if (ohms == rv3028_trickle_resistors[i])
+ break;
+
+ if (i < ARRAY_SIZE(rv3028_trickle_resistors)) {
+ /* enable trickle charger and its resistor */
+ val = RV3028_BACKUP_TCE | i;
+ } else {
+ dev_warn(&client->dev, "invalid trickle resistor value\n");
+ /* don't update the trickle charger regs */
+ val = val_old;
+ }
+ }
- if (i < ARRAY_SIZE(rv3028_trickle_resistors)) {
+ /* only update EEPROM if changes are necessary */
+ if (val_old != val) {
ret = rv3028_update_cfg(rv3028, RV3028_BACKUP, RV3028_BACKUP_TCE |
- RV3028_BACKUP_TCR_MASK, RV3028_BACKUP_TCE | i);
+ RV3028_BACKUP_TCR_MASK, val);
if (ret)
return ret;
- } else {
- dev_warn(&client->dev, "invalid trickle resistor value\n");
}
}
--
2.25.1
