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 Nosthoffcommitted@heine.so Cc: Brian Norrisbriannorris@chromium.org Cc:stable@vger.kernel.org
Reviewed-by: Brian Norrisbriannorris@chromium.org Tested-by: Brian Norrisbriannorris@chromium.org
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 */elseval->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 */-- 2.20.1