Grouping multiple monochrome LEDs into a multicolor LED device has a few
benefits over handling the group in user-space:
- The state of the LEDs relative to each other is consistent. In other
words, if 2 threads competes to set the LED to green and red, the
end-result cannot be black or yellow.
- The multicolor LED as a whole can be driven through the sysfs LED
interface.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Reviewed-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230728153731.3742339-5-jjhiblot@traphandler.com
Signed-off-by: Lee Jones <lee@kernel.org>
The MediaTek MT6370 is a highly-integrated smart power management IC,
which includes a single cell Li-Ion/Li-Polymer switching battery
charger, a USB Type-C & Power Delivery (PD) controller, dual
Flash LED current sources, a RGB LED driver, a backlight WLED driver,
a display bias driver and a general LDO for portable devices.
Add support for the MediaTek MT6370 Current Sink Type LED Indicator
driver. It can control four channels current-sink RGB LEDs with 3 modes:
constant current, PWM, and breath mode.
Co-developed-by: Alice Chen <alice_chen@richtek.com>
Signed-off-by: Alice Chen <alice_chen@richtek.com>
Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Signed-off-by: ChiaEn Wu <chiaen_wu@richtek.com>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/1df93a583c3f508a7158b83b95857e9bce235e1b.1678430444.git.chiaen_wu@richtek.com
The drivers/leds/rgb subdirectory is relatively fresh, so we move this
new PWM multi-color driver into it.
Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
The Light Pulse Generator (LPG) is a PWM-block found in a wide range of
PMICs from Qualcomm. These PMICs typically comes with 1-8 LPG instances,
with their output being routed to various other components, such as
current sinks or GPIOs.
Each LPG instance can operate on fixed parameters or based on a shared
lookup-table, altering the duty cycle over time. This provides the means
for hardware assisted transitions of LED brightness.
A typical use case for the fixed parameter mode is to drive a PWM
backlight control signal, the driver therefor allows each LPG instance
to be exposed to the kernel either through the LED framework or the PWM
framework.
A typical use case for the LED configuration is to drive RGB LEDs in
smartphones etc, for which the driver supports multiple channels to be
ganged up to a MULTICOLOR LED. In this configuration the pattern
generators will be synchronized, to allow for multi-color patterns.
The idea of modelling this as a LED driver ontop of a PWM driver was
considered, but setting the properties related to patterns does not fit
in the PWM API. Similarly the idea of just duplicating the lower bits in
a PWM and LED driver separately was considered, but this would not allow
the PWM channels and LEDs to be configured on a per-board basis. The
driver implements the more complex LED interface, and provides a PWM
interface on the side of that, in the same driver.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Luca Weiss <luca@z3ntu.xyz>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Tested-by: Marijn Suijten <marijn.suijten@somainline.org>
[On the Sony Xperia Nile Discovery, SDM630]
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Jean-Jacques Hiblot