linux/Documentation
Herman van Hazendonk 353438b310 dt-bindings: power: supply: maxim,max8903: add DC and USB input current-limit controls
Add three optional properties to the MAX8903 charger binding to
describe board-level GPIO control of the DC and USB input current
limits:

DC input (TA / DOK pin):
  - dc-current-limit-gpios (1..4 GPIOs): mux control lines feeding
    the MAX8903 IDC resistor mux;
  - dc-current-limit-mapping (uint32-matrix of {microamps,
    gpio_bit_pattern} pairs): the available current levels and the
    GPIO bit pattern that selects each level.

USB input (USB / UOK pin):
  - usb-current-limit-gpios: a single GPIO driving the IUSB pin.
    The IUSB pin is silicon-fixed by the MAX8903 datasheet (Pin
    Description): low selects 100 mA, high selects 500 mA. Only
    the GPIO mapping is board-specific; the current values are
    not exposed in DT.

A dependentRequired block ties dc-current-limit-gpios and
dc-current-limit-mapping together so an incomplete DT cannot pass
validation with only one half of the pair.

These let userspace clamp the input draw via the standard
POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT power_supply attribute. The HP
TouchPad uses both: two TLMM lines select between 0.5 A, 1.0 A,
1.5 A and 2.0 A DC input current limits behind the MAX8903B
charger, and a third TLMM line picks the IUSB 100 mA / 500 mA
limit.

These are purely additive; existing platforms remain unaffected.

Signed-off-by: Herman van Hazendonk <github.com@herrie.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260605-submit-power-max8903-dc-limit-v2-1-0c5396e98f14@herrie.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2026-07-22 01:55:43 +02:00
..
ABI power: supply: Add PbAc, NiZn, RAM, and ZnAr support 2026-07-21 22:28:11 +02:00
accel
accounting
admin-guide NFS Client Updates for Linux 7.2 2026-06-23 18:36:41 -07:00
arch soc: arm code changes for 7.2 2026-06-17 11:28:10 -07:00
block for-7.2/block-20260615 2026-06-16 13:02:47 +05:30
bpf Documentation/bpf: Refresh map_lru_hash_update.dot for rqspinlock 2026-06-07 18:46:13 -07:00
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cpu-freq cpufreq: Use policy->min/max init as QoS request 2026-06-08 18:42:14 +02:00
crypto mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
dev-tools linux_kselftest-next-7.2-rc1-second 2026-06-23 07:35:37 -07:00
devicetree dt-bindings: power: supply: maxim,max8903: add DC and USB input current-limit controls 2026-07-22 01:55:43 +02:00
doc-guide
driver-api A handful of late-arriving docs fixes, along with one document update 2026-06-25 09:09:38 -07:00
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translations USB/Thunderbolt driver changes for 7.2-rc1 2026-06-22 12:09:47 -07:00
usb
userspace-api Char/Misc/IIO/FPGA/GPIB/etc driver updates for 7.2-rc1 2026-06-22 12:20:21 -07:00
virt s390: 2026-06-25 10:21:13 -07:00
w1
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wmi modpost: Handle malformed WMI GUID strings 2026-06-12 16:01:55 +03:00
.gitignore
.renames.txt
atomic_bitops.txt
atomic_t.txt
Changes
CodingStyle
conf.py
docutils.conf
index.rst
Kconfig
Makefile
memory-barriers.txt
SubmittingPatches
subsystem-apis.rst