On Wed 27 Oct 16:19 CDT 2021, Marijn Suijten wrote: > Hi Bjorn, > > On 2021-10-22 10:25:35, Bjorn Andersson wrote: > > On Sat 09 Oct 21:39 PDT 2021, Bjorn Andersson wrote: > > > > > 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 support 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. > > > > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> > > > --- > > > > Any feedback on this? > > I asked in #linux-msm whether anything is wrong with the patterns, > since my Sony Discovery (sdm630 with a pm660l) blinks way quicker on a > pattern that's supposed to stay on for 1s and off for 1s: > > echo "0 1000 255 1000" > /sys/class/leds/rgb\:status/hw_pattern > > It however seems to be broken in the same way on an older version now > (this might be v9 or v8) which I don't remember to be the case. Can you > double-check if this is all working fine on your side? If so, I'll have > to find some time to debug it on my end. > I had missed the fact that LPG_RAMP_DURATION_REG is two registers for msg and lsb, for a total of 9 bits of duration. So what you saw was probably ticking at 232ms. Note though that the pattern uses the last time as "high pause", so I expect that you should have seen 232 ms of off, followed by 464ms of light. I've fixed this for v11, both rejecting invalid input and writing out all 9 bits. Thanks for spotting this! Bjorn
