[PATCH v2] clk: rockchip: Fix video codec clocks on rk3288

[Douglas Anderson <dianders@chromium.org>]

It appears that there is a typo in the rk3288 TRM.  For
GRF_SOC_CON0[7] it says that 0 means "vepu" and 1 means "vdpu".  It's
the other way around.

How do I know?  Here's my evidence:

1. Prior to commit 4d3e84f99628 ("clk: rockchip: describe aclk_vcodec
   using the new muxgrf type on rk3288") we always pretended that we
   were using "aclk_vdpu" and the comment in the code said that this
   matched the default setting in the system.  In fact the default
   setting is 0 according to the TRM and according to reading memory
   at bootup.  In addition rk3288-based Chromebooks ran like this and
   the video codecs worked.
2. With the existing clock code if you boot up and try to enable the
   new VIDEO_ROCKCHIP_VPU as a module (and without "clk_ignore_unused"
   on the command line), you get errors like "failed to get ack on
   domain 'pd_video', val=0x80208".  After flipping vepu/vdpu things
   init OK.
3. If I export and add both the vepu and vdpu to the list of clocks
   for RK3288_PD_VIDEO I can get past the power domain errors, but now
   I freeze when the vpu_mmu gets initted.
4. If I just mark the "vdpu" as IGNORE_UNUSED then everything boots up
   and probes OK showing that somehow the "vdpu" was important to keep
   enabled.  This is because we were actually using it as a parent.
5. After this change I can hack "aclk_vcodec_pre" to parent from
   "aclk_vepu" using assigned-clocks and the video codec still probes
   OK.
6. Rockchip has said so on the mailing list [1].

...so let's fix it.

Let's also add CLK_SET_RATE_PARENT to "aclk_vcodec_pre" as suggested
by Jonas Karlman.  Prior to the same commit you could do
clk_set_rate() on "aclk_vcodec" and it would change "aclk_vdpu".
That's because "aclk_vcodec" was a simple gate clock (always gets
CLK_SET_RATE_PARENT) and its direct parent was "aclk_vdpu".  After
that commit "aclk_vcodec_pre" gets in the way so we need to add
CLK_SET_RATE_PARENT to it too.

[1] https://lkml.kernel.org/r/1d17b015-9e17-34b9-baf8-c285dc1957aa@rock-chips.com

Fixes: 4d3e84f99628 ("clk: rockchip: describe aclk_vcodec using the new muxgrf type on rk3288")
Suggested-by: Jonas Karlman <jonas@kwiboo.se>
Suggested-by: Randy Li <ayaka@soulik.info>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v2:
- Now also has CLK_SET_RATE_PARENT for "aclk_vcodec_pre"
- Added Suggested-by tags for prior work
- Added link to Elaine saying that this is indeed correct

 drivers/clk/rockchip/clk-rk3288.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
index 5a67b7869960..51e8e799debb 100644
--- a/drivers/clk/rockchip/clk-rk3288.c
+++ b/drivers/clk/rockchip/clk-rk3288.c
@@ -219,7 +219,7 @@ PNAME(mux_hsadcout_p)	= { "hsadc_src", "ext_hsadc" };
 PNAME(mux_edp_24m_p)	= { "ext_edp_24m", "xin24m" };
 PNAME(mux_tspout_p)	= { "cpll", "gpll", "npll", "xin27m" };
 
-PNAME(mux_aclk_vcodec_pre_p)	= { "aclk_vepu", "aclk_vdpu" };
+PNAME(mux_aclk_vcodec_pre_p)	= { "aclk_vdpu", "aclk_vepu" };
 PNAME(mux_usbphy480m_p)		= { "sclk_otgphy1_480m", "sclk_otgphy2_480m",
 				    "sclk_otgphy0_480m" };
 PNAME(mux_hsicphy480m_p)	= { "cpll", "gpll", "usbphy480m_src" };
@@ -420,7 +420,7 @@ static struct rockchip_clk_branch rk3288_clk_branches[] __initdata = {
 	COMPOSITE(0, "aclk_vdpu", mux_pll_src_cpll_gpll_usb480m_p, 0,
 			RK3288_CLKSEL_CON(32), 14, 2, MFLAGS, 8, 5, DFLAGS,
 			RK3288_CLKGATE_CON(3), 11, GFLAGS),
-	MUXGRF(0, "aclk_vcodec_pre", mux_aclk_vcodec_pre_p, 0,
+	MUXGRF(0, "aclk_vcodec_pre", mux_aclk_vcodec_pre_p, CLK_SET_RATE_PARENT,
 			RK3288_GRF_SOC_CON(0), 7, 1, MFLAGS),
 	GATE(ACLK_VCODEC, "aclk_vcodec", "aclk_vcodec_pre", 0,
 		RK3288_CLKGATE_CON(9), 0, GFLAGS),
-- 
2.21.0.392.gf8f6787159e-goog