Messages in this thread | | | From | Satya Priya <> | Subject | Re: [PATCH v13 2/2] leds: Add driver for Qualcomm LPG | Date | Wed, 23 Feb 2022 10:58:54 +0530 |
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From: Bjorn Andersson <bjorn.andersson@linaro.org>
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.
Tested-by: Luca Weiss <luca@z3ntu.xyz> Tested-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> ---
Tested-by: Satya Priya <quic_c_skakit@quicinc.com>
Documentation/leds/leds-qcom-lpg.rst | 76 ++ drivers/leds/Kconfig | 3 + drivers/leds/Makefile | 3 + drivers/leds/rgb/Kconfig | 18 + drivers/leds/rgb/Makefile | 3 + drivers/leds/rgb/leds-qcom-lpg.c | 1401 ++++++++++++++++++++++++++++++++++ 6 files changed, 1504 insertions(+) create mode 100644 Documentation/leds/leds-qcom-lpg.rst create mode 100644 drivers/leds/rgb/Kconfig create mode 100644 drivers/leds/rgb/Makefile create mode 100644 drivers/leds/rgb/leds-qcom-lpg.c
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