On Fri, Aug 16, 2019 at 09:58:42AM +0200, Michael Nosthoff wrote:
> when the battery is set to sbs-mode and no gpio detection is enabled
> "health" is always returning a value even when the battery is not present.
> All other fields return "not present".
> This leads to a scenario where the driver is constantly switching between
> "present" and "not present" state. This generates a lot of constant
> traffic on the i2c.
That depends on how often you're checking the "health" attribute,
doesn't it? But anyway, the bug is real.
> This commit changes the response of "health" to an error when the battery
> is not responding leading to a consistent "not present" state.
Ack, and thanks for the fix.
> Fixes: 76b16f4cdfb8 ("power: supply: sbs-battery: don't assume
> MANUFACTURER_DATA formats")
>
> Signed-off-by: Michael Nosthoff <committed@xxxxxxxx>
> Cc: Brian Norris <briannorris@xxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx>
Tested-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> ---
> drivers/power/supply/sbs-battery.c | 25 ++++++++++++++++---------
> 1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
> index 2e86cc1e0e35..f8d74e9f7931 100644
> --- a/drivers/power/supply/sbs-battery.c
> +++ b/drivers/power/supply/sbs-battery.c
> @@ -314,17 +314,22 @@ static int sbs_get_battery_presence_and_health(
> {
> int ret;
>
> - if (psp == POWER_SUPPLY_PROP_PRESENT) {
> - /* Dummy command; if it succeeds, battery is present. */
> - ret = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
> - if (ret < 0)
> - val->intval = 0; /* battery disconnected */
> - else
> - val->intval = 1; /* battery present */
> - } else { /* POWER_SUPPLY_PROP_HEALTH */
> + /* Dummy command; if it succeeds, battery is present. */
> + ret = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
> +
> + if (ret < 0) { /* battery not present*/
> + if (psp == POWER_SUPPLY_PROP_PRESENT) {
> + val->intval = 0;
> + return 0;
Technically, you don't need the 'return 0' (and if we care about
symmetry: the TI version doesn't), since the caller knows that "not
present" will yield errors. I'm not sure which version makes more sense.
> + }
> + return ret;
> + }
> +
> + if (psp == POWER_SUPPLY_PROP_PRESENT)
> + val->intval = 1; /* battery present */
> + else /* POWER_SUPPLY_PROP_HEALTH */
> /* SBS spec doesn't have a general health command. */
> val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
> - }
>
> return 0;
> }
> @@ -626,6 +631,8 @@ static int sbs_get_property(struct power_supply *psy,
> else
> ret = sbs_get_battery_presence_and_health(client, psp,
> val);
> +
> + /* this can only be true if no gpio is used */
> if (psp == POWER_SUPPLY_PROP_PRESENT)
> return 0;
> break;
> --
> 2.20.1
>
