linux-kernel - [PATCH v4 0/2] Add Support for LTC3220 18 Channel LED Driver

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Message-ID: <20260126-ltc3220-driver-v4-0-c59517206c24@analog.com>
Date: Mon, 26 Jan 2026 08:10:42 +0800
From: Edelweise Escala <edelweise.escala@...log.com>
To: Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>,
        Rob Herring
	<robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>
CC: <linux-leds@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Edelweise Escala
	<edelweise.escala@...log.com>,
        Conor Dooley <conor.dooley@...rochip.com>
Subject: [PATCH v4 0/2] Add Support for LTC3220 18 Channel LED Driver

The LTC3220/LTC3220-1 is a multi-display LED driver, which contains a
high-efficiency, low-noise charge pump to provide power to up to
18 LED current sources. The LEDs are individually configurable to
64-step linear brightness control, blinking and gradation control
via 2-wire I2C interface. The blinking and gradation configuration
is shared across all LED.

LTC3220 has a quick write function which allows changing the brightness
on all LEDS simultaneously when the brightness is changed on led 1.
For this leds are aggregated in the device tree and on probe we check
if led-sources exist to enable quick write. 
We would like to know if this approach is alright?
Another way we might want to know is, is it alright to just make a
virtual led for the quick write function. Changing brightness on 
the virtual led will change the brightness for all.

Signed-off-by: Edelweise Escala <edelweise.escala@...log.com>
---
Changes in v4:
- Rename leds-ltc3220.yaml to adi,ltc3220.yaml
- Add Reviewed-by: Conor Dooley <conor.dooley@...rochip.com> on
  adi,ltc3220.yaml
Other V1 comments I think already addressed
- Subject commit message was already changed to match hardware
- Fixed wrapping after description
- Dropped "Bindings for" in descriptions and improved description to match hardware
- Dropped adi,ltc3220-1
- Dropped redundant description on reset-gpios
- Dropped adi,force-cpo-level
- Dropped adi,quick-write in favor of aggregated LED
- Used consistent quotes ^led@([1-9]|1[0-8])$
- Fixed wrapping on error messages

- Link to v3: https://lore.kernel.org/r/20260120-ltc3220-driver-v3-0-fef612ec4faa@analog.com

Changes in v3:
- Dropped quick-write on bindings and added aggregated led instead.
- Add aggregated led example.
- Modify quick write to check if there is aggregated led, if there is
  aggregated led enable quick write.
- Use DEFINE_SIMPLE_DEV_PM_OPS instead of SIMPLE_DEV_PM_OPS.
- Link to v2: https://lore.kernel.org/r/20260112-ltc3220-driver-v2-0-d043058fc4df@analog.com

Changes in v2:
leds-ltc3220.yaml changes
- Fix wrapping on description
- Improve description and commit messge to describe hardware
- Drop ltc3220-1
- Drop charge pump
ltc3220.c changes
- Fix wrapping
- Drop ltc3220-1
- Drop devname_mandatory
- Link to v1: https://lore.kernel.org/r/20260106-ltc3220-driver-v1-0-73601d6f1649@analog.com

---
Edelweise Escala (2):
      dt-bindings: leds: Add LTC3220 18 channel LED Driver
      leds: ltc3220: Add Support for LTC3220 18 channel LED Driver

 .../devicetree/bindings/leds/adi,ltc3220.yaml      | 120 ++++++
 MAINTAINERS                                        |   8 +
 drivers/leds/Kconfig                               |  10 +
 drivers/leds/Makefile                              |   1 +
 drivers/leds/leds-ltc3220.c                        | 455 +++++++++++++++++++++
 5 files changed, 594 insertions(+)
---
base-commit: 8856d7fe1758937ac528770f552ec58c388c255b
change-id: 20260106-ltc3220-driver-f9ab6cc9d1e4

Best regards,
-- 
Edelweise Escala <edelweise.escala@...log.com>