From: Yauhen Kharuzhy <jekhor@gmail.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: linux-kernel@vger.kernel.org,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH 2/2] extcon intel-cht-wc: Enable external charger
Date: Wed, 20 Feb 2019 23:28:36 +0300 [thread overview]
Message-ID: <20190220202836.GA23567@jeknote.loshitsa1.net> (raw)
In-Reply-To: <6a7be360-8da3-f1e6-6ca7-f55b3b2c60df@redhat.com>
On Wed, Feb 20, 2019 at 05:42:28PM +0100, Hans de Goede wrote:
> > > The input-current-limit only specifies how much current the charger may
> > > draw from the micro-usb for both supplying the laptop as well as for
> > > charging the battery combined. You can safely set this as high as
> > > the charger can handle (2A for a dedicated charger).
> > >
> > > The BQ25892 should have a *separate* setting for the max current to
> > > use while charging the battery (assuming that the input current allows
> > > drawing enough current in the first place). I would hope that those bits
> > > have some sane value set from the firmware...
> >
> > Yes, the charger has separate battery current limit but firmware doesn't
> > change its default value (2048 mA) while Lenovo's software driver does.
> > It set battery charging limit to 4 A and input limit to 2 A (it makes
> > sense because Lenovo adapter and BQ25892 both support voltage increasing
> > upto 12V).
>
> Hmm, I guess your device uses a separate power-barrel charging conector
> then? 12v over micro-usb requires special negotiation which the Whiskey Cove
> PMIC does not support AFAIK.
The Yoga Book supports kind of quick charging by negotiate voltage with
'current pulse protocol' supported by BQ25892 and Lenovo's wall cube.
I think that PMIC is not connected to VBUS directly. After charging
started, BQ25892 driver can ask power adapter to increase voltage
number of times upto 12V. See
https://github.com/jekhor/yogabook-linux-kernel/blob/master/drivers/power/supply/bq25890_charger.c#L918
for example.
>
> In either case if you want to increase the max battery current to 4A
> in the kernel, then this will have to be guarded by a DMI check.
Yes.
>
> I beieve the way to do this wuld be throuh a device-property on the
> charger which gets set from drivers/i2c/busses/i2c-cht-wc.c, but as
> said this needs to be behind a DMI check, e cannot just g and boost
> the max charge current to 4A everywhere.
Yes, I use such method already in the my kernel:
https://github.com/jekhor/yogabook-linux-kernel/blob/master/drivers/i2c/busses/i2c-cht-wc.c#L247
Anyway, charger tweaking will be next iteration, now I want to complete
current extcon stuff/
> Regards,
>
> Hans
--
Yauhen Kharuzhy
next prev parent reply other threads:[~2019-02-20 20:28 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190210204024epcas3p36ea277b499e647b870d538c5680309bd@epcas3p3.samsung.com>
2019-02-10 20:36 ` [PATCH 0/2] extcon: Intel Cherry Trail Whiskey Cove PMIC and external charger tweaks Yauhen Kharuzhy
2019-02-10 20:36 ` [PATCH 1/2] extcon-intel-cht-wc: Make charger detection co-existed with OTG host mode Yauhen Kharuzhy
2019-02-13 23:15 ` Hans de Goede
2019-02-14 7:09 ` Yauhen Kharuzhy
2019-02-14 15:32 ` Hans de Goede
2019-02-14 14:22 ` Hans de Goede
2019-02-10 20:36 ` [PATCH 2/2] extcon intel-cht-wc: Enable external charger Yauhen Kharuzhy
2019-02-14 16:31 ` Hans de Goede
2019-02-15 6:32 ` Yauhen Kharuzhy
2019-02-17 21:52 ` Yauhen Kharuzhy
2019-02-18 9:24 ` Hans de Goede
2019-02-18 15:07 ` Yauhen Kharuzhy
2019-02-19 13:39 ` Hans de Goede
2019-02-19 20:20 ` Yauhen Kharuzhy
2019-02-20 16:42 ` Hans de Goede
2019-02-20 20:28 ` Yauhen Kharuzhy [this message]
2019-02-21 9:33 ` Hans de Goede
2019-02-13 23:00 ` [PATCH 0/2] extcon: Intel Cherry Trail Whiskey Cove PMIC and external charger tweaks Hans de Goede
2019-02-14 10:07 ` Hans de Goede
2019-02-14 12:47 ` Andy Shevchenko
[not found] ` <CAKWEGV7SGDMttB6uHwnkyjWk+bmSmZ-vTSOXHg1UAgLBeqnaXw@mail.gmail.com>
2019-02-14 15:05 ` Hans de Goede
2019-02-15 7:01 ` Yauhen Kharuzhy
2019-02-15 9:26 ` Hans de Goede
2019-02-15 9:29 ` Andy Shevchenko
2019-02-15 9:33 ` Hans de Goede
2019-02-15 7:08 ` Chanwoo Choi
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