On 22/06/2023 09:16:09+0200, Andrej Picej wrote:
> 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.
What about using aux-voltage-chargeable which is the generic property
for this?
> ---
> 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
>
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
