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.
Best regards
Henrik Grimler
> Signed-off-by: Artur Weber <aweber.kernel@xxxxxxxxx>
>
> 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>
>
