UPSTREAM: clk: rockchip: only enter pll slow-mode directly before reboots on rk3288

As commit 1d33929e2a2b ("clk: rockchip: switch PLLs to slow mode before
reboot for rk3288") states, switching the PLLs to slow-mode is only
necessary when rebooting using the soft-reset done through the CRU.

The dwc2 controllers used create really big number of interrupts in
special constellations involving usb-hubs and their number is so high,
it can even overwhelm the interrupt handler if the cpu-speed os to low.

Right now the PLLs are put into slow-mode in a shutdown syscore_ops
callback which means it happens on all reboots (not only the soft-reset
ones) and even on poweroff actions.

This can result in the system not powering off and getting stuck instead,
so we should move the slow-mode change nearer to the actual reboot action.

For this we introduce the possiblity to also set a callback that gets
called from the restart-handler directly prior to restarting the system
and move the shutdown-callback to this new option.

With this the slow-mode switch is done only on the necessary reboots
and also has a smaller possibility of causing artifacts.

Fixes: 1d33929e2a2b ("clk: rockchip: switch PLLs to slow mode before reboot for rk3288")
Signed-off-by: Heiko Stuebner <heiko.stuebner@collabora.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
(cherry picked from commit dfff24bde7fb8d57482e907d5dfb0be3a9e28119)

Conflicts:

	drivers/clk/rockchip/clk-rk3228.c
[zx: there is no rk3228 clock controller, apply for clk-rk3366]

Change-Id: I2e91afd893c87eb3ab8a41db1fe81f5c43409951
Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/clk/rockchip/clk-rk3036.c b/drivers/clk/rockchip/clk-rk3036.c
index 34c78f499ab7..c289fdc3a17f 100644
--- a/drivers/clk/rockchip/clk-rk3036.c
+++ b/drivers/clk/rockchip/clk-rk3036.c
@@ -488,6 +488,6 @@ static void __init rk3036_clk_init(struct device_node *np)
 	rockchip_register_softrst(np, 9, reg_base + RK2928_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-	rockchip_register_restart_notifier(RK2928_GLB_SRST_FST);
+	rockchip_register_restart_notifier(RK2928_GLB_SRST_FST, NULL);
 }
 CLK_OF_DECLARE(rk3036_cru, "rockchip,rk3036-cru", rk3036_clk_init);