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| author | Bjorn Andersson <bjorn.andersson@linaro.org> | 2022-03-03 22:43:00 +0100 |
|---|---|---|
| committer | Pavel Machek <pavel@ucw.cz> | 2022-05-04 09:17:31 +0200 |
| commit | 24e2d05d1b68981f22c984c766fabc5a93c83dba (patch) | |
| tree | fe4321f09ea811d9873054cc81818731aed81b83 /drivers/leds/Makefile | |
| parent | dt-bindings: leds: Add Qualcomm Light Pulse Generator binding (diff) | |
| download | linux-24e2d05d1b68981f22c984c766fabc5a93c83dba.tar.xz linux-24e2d05d1b68981f22c984c766fabc5a93c83dba.zip | |
leds: Add driver for Qualcomm LPG
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>
Diffstat (limited to 'drivers/leds/Makefile')
| -rw-r--r-- | drivers/leds/Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index e58ecb36360f..4fd2f92cd198 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -99,6 +99,9 @@ obj-$(CONFIG_LEDS_USER) += uleds.o # Flash and Torch LED Drivers obj-$(CONFIG_LEDS_CLASS_FLASH) += flash/ +# RGB LED Drivers +obj-$(CONFIG_LEDS_CLASS_MULTICOLOR) += rgb/ + # LED Triggers obj-$(CONFIG_LEDS_TRIGGERS) += trigger/ |