Re: [PATCH v3 2/2] power: supply: sbs-battery: don't assume i2c errors as battery disconnect

From: Nicolas Boichat
Date: Thu Aug 13 2020 - 01:26:29 EST


On Thu, Aug 13, 2020 at 1:11 PM Ikjoon Jang <ikjn@xxxxxxxxxxxx> wrote:
>
> Current sbs-battery considers all smbus errors as disconnection events
> when battery-detect pin isn't supplied, and restored to present state back
> when any successful transaction is made.
>
> This can lead to unlimited state changes between present and !present
> when one unsupported command was requested and other following commands
> were successful, e.g. udev rules tries to read multiple properties.
>
> This patch checks battery presence by reading known good command to
> check battery existence.
>
> Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>

Looks good now, AFAICT. Thanks!

Reviewed-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx>

> ---
> drivers/power/supply/sbs-battery.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
> index 6acb4ea25d2a..2e32fde04628 100644
> --- a/drivers/power/supply/sbs-battery.c
> +++ b/drivers/power/supply/sbs-battery.c
> @@ -878,10 +878,17 @@ static int sbs_get_property(struct power_supply *psy,
> if (!chip->enable_detection)
> goto done;
>
> - if (!chip->gpio_detect &&
> - chip->is_present != (ret >= 0)) {
> - sbs_update_presence(chip, (ret >= 0));
> - power_supply_changed(chip->power_supply);
> + if (!chip->gpio_detect && chip->is_present != (ret >= 0)) {
> + bool old_present = chip->is_present;
> + union power_supply_propval val;
> +
> + ret = sbs_get_battery_presence_and_health(
> + client, POWER_SUPPLY_PROP_PRESENT, &val);
> +
> + sbs_update_presence(chip, !ret && val.intval);
> +
> + if (old_present != chip->is_present)
> + power_supply_changed(chip->power_supply);
> }
>
> done:
> @@ -1067,11 +1074,13 @@ static int sbs_probe(struct i2c_client *client)
> * to the battery.
> */
> if (!(force_load || chip->gpio_detect)) {
> - rc = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
> + union power_supply_propval val;
>
> - if (rc < 0) {
> - dev_err(&client->dev, "%s: Failed to get device status\n",
> - __func__);
> + rc = sbs_get_battery_presence_and_health(
> + client, POWER_SUPPLY_PROP_PRESENT, &val);
> + if (rc < 0 || !val.intval) {
> + dev_err(&client->dev, "Failed to get present status\n");
> + rc = -ENODEV;
> goto exit_psupply;
> }
> }
> --
> 2.28.0.236.gb10cc79966-goog
>