2023-06-23 08:22:45

by Andrej Picej

Subject: [PATCH v3] rtc: rv3028: Add support for "aux-voltage-chargeable" property

Property "trickle-resistor-ohms" allows us to set trickle charger
resistor. However there is no possibility to disable it afterwards.

Add support for "aux-voltage-chargeable" property which can be used to
enable/disable the trickle charger circuit explicitly. The default
behavior of the code is kept as it is!

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 <[email protected]>
---
Changes in v3:
- use "aux-voltage-chargeable" to enable/disable trickle charger,
- put trickle charger init code in a separate function.
---
drivers/rtc/rtc-rv3028.c | 80 ++++++++++++++++++++++++++++++----------
1 file changed, 61 insertions(+), 19 deletions(-)

diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index ec5d7a614e2d..e3338765c687 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -855,11 +855,68 @@ static const struct regmap_config regmap_config = {
.max_register = 0x37,
};

+static u8 rv3028_set_trickle_charger(struct rv3028_data *rv3028,
+ struct i2c_client *client)
+{
+ int ret, val_old, val;
+ u32 ohms, chargeable;
+
+ 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);
+ val = val_old;
+
+ /* setup trickle charger */
+ if (!device_property_read_u32(&client->dev, "trickle-resistor-ohms",
+ &ohms)) {
+ 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");
+ }
+ }
+
+ if (!device_property_read_u32(&client->dev, "aux-voltage-chargeable",
+ &chargeable)) {
+ switch (chargeable) {
+ case 0:
+ val &= ~RV3028_BACKUP_TCE;
+ break;
+ case 1:
+ val |= RV3028_BACKUP_TCE;
+ break;
+ default:
+ dev_warn(&client->dev,
+ "unsupported aux-voltage-chargeable value\n");
+ break;
+ }
+ }
+
+ /* 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, val);
+ if (ret)
+ return ret;
+ }
+
+ return ret;
+}
+
static int rv3028_probe(struct i2c_client *client)
{
struct rv3028_data *rv3028;
int ret, status;
- u32 ohms;
struct nvmem_config nvmem_cfg = {
.name = "rv3028_nvram",
.word_size = 1,
@@ -937,24 +994,9 @@ 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;
-
- for (i = 0; i < ARRAY_SIZE(rv3028_trickle_resistors); i++)
- if (ohms == rv3028_trickle_resistors[i])
- break;
-
- if (i < ARRAY_SIZE(rv3028_trickle_resistors)) {
- ret = rv3028_update_cfg(rv3028, RV3028_BACKUP, RV3028_BACKUP_TCE |
- RV3028_BACKUP_TCR_MASK, RV3028_BACKUP_TCE | i);
- if (ret)
- return ret;
- } else {
- dev_warn(&client->dev, "invalid trickle resistor value\n");
- }
- }
+ ret = rv3028_set_trickle_charger(rv3028, client);
+ if (ret)
+ return ret;

ret = rtc_add_group(rv3028->rtc, &rv3028_attr_group);
if (ret)
--
2.25.1

2023-07-27 21:42:19

by Alexandre Belloni

Subject: Re: [PATCH v3] rtc: rv3028: Add support for "aux-voltage-chargeable" property

On Fri, 23 Jun 2023 10:15:33 +0200, Andrej Picej wrote:
> Property "trickle-resistor-ohms" allows us to set trickle charger
> resistor. However there is no possibility to disable it afterwards.
>
> Add support for "aux-voltage-chargeable" property which can be used to
> enable/disable the trickle charger circuit explicitly. The default
> behavior of the code is kept as it is!
>
> [...]

Applied, thanks!

[1/1] rtc: rv3028: Add support for "aux-voltage-chargeable" property
commit: 3c87b351809f220294aec3c0df7b078ff5c5b15b

Best regards,

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com