Hi again Artur,
On Thu, Aug 01, 2024 at 08:23:26AM +0200, Henrik Grimler wrote:
> Hi Artur,
>
> On Mon, Jul 29, 2024 at 07:47:34PM +0200, Artur Weber wrote:
> > This patchset does the following:
> >
> > - Add CURRENT_MAX and INPUT_CURRENT_MAX power supply properties to
> > expose the "fast charge current" (maximum current from charger to
> > battery) and "CHGIN input current limit" (maximum current from
> > external supply to charger).
> >
> > - Add functions for toggling charging and OTG modes.
> >
> > - Add an extcon-based handler that enables charging or OTG depending
> > on the cable type plugged in. The extcon device to use for cable
> > detection can be specified in the device tree, and is entirely
> > optional.
> >
> > The extcon listener implementation is inspired by the rt5033 charger
> > driver (commit 8242336dc8a8 ("power: supply: rt5033_charger: Add cable
> > detection and USB OTG supply")).
>
> Tested on exynos4412-i9305 (after applying the changes in patch 8 - 10
> to exynos4412-midas.dtsi). It works well, device correctly identifies
> a usb cable connected to charger or a usb cable connected to computer,
> and sets a limit of 1.8 A and 0.5 A in the two cases.
>
> I did notice that device does not always detect cable insertion, so I
> can occassionally get two de-attach events in a row. Cable was
> inserted between 428 and 462 in below log snippet:
>
> [ 389.458399] max77693-muic max77693-muic: external connector is attached(chg_type:0x3, prev_chg_type:0x3)
> [ 389.469765] max77693-charger max77693-charger: fast charging. connector type: 6
> [ 428.151857] max77693-muic max77693-muic: external connector is detached(chg_type:0x3, prev_chg_type:0x0)
> [ 428.160319] max77693-charger max77693-charger: not charging. connector type: 13
> [ 462.156048] max77693-muic max77693-muic: external connector is detached(chg_type:0x0, prev_chg_type:0x0)
> [ 469.881925] max77693-muic max77693-muic: external connector is attached(chg_type:0x3, prev_chg_type:0x3)
> [ 469.890049] max77693-charger max77693-charger: fast charging. connector type: 6
>
> but this is probably an issue in extcon driver though rather than
> charger.
>
> I have not tested so that MHL still works, as I do not have access to
> that cable at the moment, will try it in a few days.
MHL now tested on exynos4412-i9300 as well. It works, and the series
fixes so that we can hotplug the cable (with a few patches to make
sii9324 use extcon as well), before we had to connect cable before
boot and rely on bootloader to setup everything. Thanks!
> > Signed-off-by: Artur Weber <aweber.kernel@xxxxxxxxx>
Tested-by: Henrik Grimler <henrik@xxxxxxxxxx>
Best regards,
Henrik Grimler
> > v3 no longer uses the CHARGER regulator to manage the power status, and
> > that's for two reasons:
> >
> > - Regulator enable/disable behavior was interfering with how the power
> > supply driver worked (we occasionally got "unbalanced disables"
> > errors when switching charging state, despite checking for the
> > regulator status with regulator_is_enabled() - the CHARGER reg would
> > report as enabled despite the enable count being 0).
> > This broke OTG insertion if the OTG cable was plugged in first, and
> > sometimes caused warnings on unsuspend.
> >
> > - Changing the charging values directly in the power supply driver is
> > less opaque and lets us avoid bringing in a dependency on regulators.
> >
> > It also splits the current limits back into two properties:
> > INPUT_CURRENT_LIMIT and CONSTANT_CHARGE_CURRENT_MAX. Again, there are
> > two reasons for this split:
> >
> > - They are two separate current controls, one for USB->charger and one
> > for charger->battery, and they have different limits (0-2.1A for CC
> > vs 60mA-2.58A for input). Given that the power supply core has the
> > properties for both values separately, it's more logical to present
> > them as such.
> >
> > - It's safer to keep these separate; CONSTANT_CHARGE_CURRENT_MAX is
> > pretty explicitly only set *once* - at probe time with a safe value
> > specified in the DT. This way, INPUT_CURRENT_LIMIT is safer to modify
> > since in the event of an invalid value the CC current will hold back
> > the extra current thus preventing damage to the battery.
> >
> > The latter is relevant as I'm working on a follow-up patchset that
> > allows for controlling the charging parameters using power supply
> > properties/sysfs properties rather than the CHARGER regulator.
> >
> > Note that the CHARGER regulator gets disabled automatically if it's
> > not used, which will disable charging if it was auto-enabled by the
> > extcon code. This can be worked around by re-attaching the cable, or
> > more properly by removing the CHARGER regulator from DT for devices
> > that use the extcon-based charger management, as has been done in the
> > Galaxy Tab 3 8.0 DTSI.
> >
> > See v1 for old description:
> >
> > https://lore.kernel.org/r/20240530-max77693-charger-extcon-v1-0-dc2a9e5bdf30@xxxxxxxxx
> > ---
> > Changes in v3:
> > - Drop uses of CHARGER regulator, manage registers directly in power
> > supply driver instead
> > - Link to v2: https://lore.kernel.org/r/20240715-max77693-charger-extcon-v2-0-0838ffbb18c3@xxxxxxxxx
> >
> > Changes in v2:
> > - Changed to use monitored-battery for charge current value
> > - Both current limit variables are now set by the CHARGER regulator
> > - Link to v1: https://lore.kernel.org/r/20240530-max77693-charger-extcon-v1-0-dc2a9e5bdf30@xxxxxxxxx
> >
> > ---
> > Artur Weber (10):
> > dt-bindings: power: supply: max77693: Add monitored-battery property
> > dt-bindings: power: supply: max77693: Add maxim,usb-connector property
> > power: supply: max77693: Expose input current limit and CC current properties
> > power: supply: max77693: Set charge current limits during init
> > power: supply: max77693: Add USB extcon detection for enabling charging
> > power: supply: max77693: Add support for detecting and enabling OTG
> > power: supply: max77693: Set up charge/input current according to cable type
> > ARM: dts: samsung: exynos4212-tab3: Add battery node with charge current value
> > ARM: dts: samsung: exynos4212-tab3: Add USB connector node
> > ARM: dts: exynos4212-tab3: Drop CHARGER regulator
> >
> > .../bindings/power/supply/maxim,max77693.yaml | 15 +
> > arch/arm/boot/dts/samsung/exynos4212-tab3.dtsi | 22 +-
> > drivers/power/supply/Kconfig | 1 +
> > drivers/power/supply/max77693_charger.c | 302 ++++++++++++++++++++-
> > include/linux/mfd/max77693-private.h | 12 +
> > 5 files changed, 337 insertions(+), 15 deletions(-)
> > ---
> > base-commit: 0c3836482481200ead7b416ca80c68a29cfdaabd
> > change-id: 20240525-max77693-charger-extcon-9ebb7bad83ce
> >
> > Best regards,
> > --
> > Artur Weber <aweber.kernel@xxxxxxxxx>
> >
