Hi, On 11/16/21 12:07, Yauhen Kharuzhy wrote: > > > аў, 16 ліс 2021, 12:33 карыстальнік Hans de Goede <hdegoede@xxxxxxxxxx <mailto:hdegoede@xxxxxxxxxx>> напісаў: > > Hi Yauhen, > > On 11/15/21 11:11, Yauhen Kharuzhy wrote: > > On Sun, Nov 14, 2021 at 06:03:25PM +0100, Hans de Goede wrote: > >> Add a bq25890_set_otg_cfg() helper function, this is a preparation > >> patch for adding regulator support. > >> > >> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx <mailto:hdegoede@xxxxxxxxxx>> > >> --- > >> drivers/power/supply/bq25890_charger.c | 28 ++++++++++++++------------ > >> 1 file changed, 15 insertions(+), 13 deletions(-) > >> > >> diff --git a/drivers/power/supply/bq25890_charger.c b/drivers/power/supply/bq25890_charger.c > >> index 2bdfb58cda75..3c41fe86b3d3 100644 > >> --- a/drivers/power/supply/bq25890_charger.c > >> +++ b/drivers/power/supply/bq25890_charger.c > >> @@ -801,6 +801,17 @@ static int bq25890_power_supply_init(struct bq25890_device *bq) > >> return PTR_ERR_OR_ZERO(bq->charger); > >> } > >> > >> +static int bq25890_set_otg_cfg(struct bq25890_device *bq, u8 val) > >> +{ > >> + int ret; > >> + > >> + ret = bq25890_field_write(bq, F_OTG_CFG, val); > >> + if (ret < 0) > >> + dev_err(bq->dev, "Error switching to boost/charger mode: %d\n", ret); > > > > Just a note: if a connected USB device has relative big capacitor > > at power wires inside, then a starting current pulse may be enough to > > overload the boost reguator and VBUS will not be powered. I met this > > at Yoga Book: the firmware set boost current limit to 1.4 A (default > > value for bq25892) but when USB hub connected, the BOOST_FAULT event > > appeared. > > > > To avoid this, Lenovo uses following trick in its kernel: set a boost > > current limit to big value (2.1 A), wait some time (500 ms) and set > > the current limit to right value (1.4A). This provides enough current to > > charge capacitors in the connected device but saves desired long-time limit > > to prevent overloading if the device consumes too much power itself. > > Right I saw this in your git repo, but I cannot reproduce the issue (1) > I was hoping that since you can reproduce this, that you can rebase > your fix on top of my patch-set ? > > Also I'm wondering if this behavior should be the default, I believe > that the max. boost current may also be dependent on some external > factors, so maybe we should make this behavior conditional on a > new device-property ? > > Yes, defining of max VBUS current may be a good idea. Another possible approach may be to use some empirical multiplier, like 150% of max 'long time' current limit setting. I almost sure that all hardware will work with short impulse of such current, its usual condition at device connection. > > > Regards, > > Hans > > > > 1) I must admit I did not try really hard, I guess I could try an > USB powered hdd enclosure with a spinning disk > > What device are you seeing this with? > > I cannot remember exactly device but this was a USB hub, possible with keyboard, mouse receiver and USB dongle inserted. I can recheck this issue but one week after, when will return home. So as I mentioned before I've just tried to reproduce this problem, but I cannot reproduce it with an 2.5" USB disk enclosure with a spinning disk, which typically will cause a nice current-peak when spinning up. I think this might also require an almost empty battery to reproduce ? Regards, Hans
