Brian Norris wrote:
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.
At least on my Hardware I had constant traffic from the moment the
device was probed.
I have no userland process accessing the device.
I'm guessing that it has something todo with the call to
'power_supply_changed'.
This done at the end of 'sbs_get_property' if the presence state changed and
no gpio is used. I suspect it triggers a readout of all the properties
and leads to this
endless loop?
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>
thanks for review!
---
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
