This is a note to let you know that I've just added the patch titled
clk: qcom: gdsc: Keep RETAIN_FF bit set if gdsc is already on
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
clk-qcom-gdsc-keep-retain_ff-bit-set-if-gdsc-is-alre.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 468a443e3f7146470f9ccd1646e9703a54353a83
Author: Stephen Boyd <sboyd@xxxxxxxxxx>
Date: Fri Oct 16 19:01:37 2020 -0700
clk: qcom: gdsc: Keep RETAIN_FF bit set if gdsc is already on
[ Upstream commit fda48bf5c86d88fd7074e318f290ad636dff4eaa ]
If the GDSC is enabled out of boot but doesn't have the retain ff bit
set we will get confusing results where the registers that are powered
by the GDSC lose their contents on the first power off of the GDSC but
thereafter they retain their contents. This is because gdsc_init() fails
to make sure the RETAIN_FF bit is set when it probes the GDSC the first
time and thus powering off the GDSC causes the register contents to be
reset. We do set the RETAIN_FF bit the next time we power on the GDSC,
see gdsc_enable(), so that subsequent GDSC power off's don't lose
register contents state.
Forcibly set the bit at device probe time so that the kernel's assumed
view of the GDSC is consistent with the state of the hardware. This
fixes a problem where the audio PLL doesn't work on sc7180 when the
bootloader leaves the lpass_core_hm GDSC enabled at boot (e.g. to make a
noise) but critically doesn't set the RETAIN_FF bit.
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Taniya Das <tdas@xxxxxxxxxxxxxx>
Cc: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
Fixes: 173722995cdb ("clk: qcom: gdsc: Add support to enable retention of GSDCR")
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20201017020137.1251319-1-sboyd@xxxxxxxxxx
Reviewed-by: Taniya Das <tdas@xxxxxxxxxxxxxx>
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx> Tested-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index bfc4ac02f9ea2..af26e0695b866 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -358,6 +358,14 @@ static int gdsc_init(struct gdsc *sc)
if ((sc->flags & VOTABLE) && on)
gdsc_enable(&sc->pd);
+ /*
+ * Make sure the retain bit is set if the GDSC is already on, otherwise
+ * we end up turning off the GDSC and destroying all the register
+ * contents that we thought we were saving.
+ */
+ if ((sc->flags & RETAIN_FF_ENABLE) && on)
+ gdsc_retain_ff_on(sc);
+
/* If ALWAYS_ON GDSCs are not ON, turn them ON */
if (sc->flags & ALWAYS_ON) {
if (!on)
