Hi Merlijn, On Thu, Feb 15, 2018 at 12:53:32PM +0100, Merlijn Wajer wrote: > On my N900, with kernel 4.15-rc6 (I realise it's not the very latest), > the (charging) status of the battery is confusing or plain wrong: > > When no charger is connected, this is reported: > > # cat > /sys/devices/platform/68000000.ocp/48072000.i2c/i2c-2/2-0055/power_supply/bq27200-0/status > Not charging > > When a charged is connected, this is reported: > > # cat > /sys/devices/platform/68000000.ocp/48072000.i2c/i2c-2/2-0055/power_supply/bq27200-0/status > Charging > > The odd part here is "Not charging" -- on all my other devices, a device > that is discharging is reported as "Discharging", not as "Not charging". "Not charging" is reported, when the battery is neither charged, nor dis-charged. It's supposed to be used when a charger is connected without charging the battery. > [...] > > The N900 reporting "Not charging" when it is in fact discharging > confuses userspace, such as UPower. It's a bug. > I am not particularly versed in the N900/RX-51 drivers, but from a > quick glance this line looks suspicious [1]. > > Cheers, > Merlijn > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/power/supply/bq27xxx_battery.c#n1673 Basically the bq27xxx driver assumes, that charger is connected. I guess the problem is, that the N900 devicetree does not specify, that the bq27xxx is supplied by the charger, so power_supply_am_i_supplied returns -ENODEV. This can be fixed by adding the following to the N900 DT: &bq27200 { power-supplies = <&bq24150a>; }; But there is also a bug in the bq27xxx driver, that should cope with no charger being specified. The following patch should fix the issue. I currently don't have my N900 with me. Could you give it a try? -- Sebastian -------------------------------------------------- From 47642af85cc9ffc829b5f478e71b1751a98e2659 Mon Sep 17 00:00:00 2001 From: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxxxx> Date: Thu, 15 Feb 2018 21:28:40 +0100 Subject: [PATCH] power: supply: bq27xxx: support missing supplier device power_supply_am_i_supplied() can return negative error codes. In this case we should assume, that no charger is connected and the battery should be marked as DISCHARGING instead of NOT_CHARGING. Reported-by: Merlijn Wajer <merlijn@xxxxxxxxxx> Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxxxx> --- drivers/power/supply/bq27xxx_battery.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c index d99981542a46..7ce60519b1bc 100644 --- a/drivers/power/supply/bq27xxx_battery.c +++ b/drivers/power/supply/bq27xxx_battery.c @@ -1670,7 +1670,7 @@ static int bq27xxx_battery_status(struct bq27xxx_device_info *di, status = POWER_SUPPLY_STATUS_FULL; else if (di->cache.flags & BQ27000_FLAG_CHGS) status = POWER_SUPPLY_STATUS_CHARGING; - else if (power_supply_am_i_supplied(di->bat)) + else if (power_supply_am_i_supplied(di->bat) > 0) status = POWER_SUPPLY_STATUS_NOT_CHARGING; else status = POWER_SUPPLY_STATUS_DISCHARGING; -- 2.15.1 -- Sebastian
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