[PATCH] clk: qcom: mmcc-sdm660: enable the parent when pclk0_clk_src changes rate

[Fabricio Akio via B4 Relay <devnull+fabricioakio.gmail.com@kernel.org>]

From: Fabricio Akio <fabricioakio@gmail.com>

pclk0_clk_src is fed by the DSI PHY PLL, which
dsi_pll_14nm_vco_set_rate() resets and only clk_prepare() restarts. The
DSI host sets the link rates before it prepares the PLL, so the RCG is
updated against a stopped source, and if it is enabled at that point
the update times out:

  pclk0_clk_src: rcg didn't update its configuration.

Seen on a board whose simple-framebuffer node lists the pixel clock:
the RCG then reads enabled at msm's first modeset.

Set CLK_OPS_PARENT_ENABLE so the core prepares the PLL around the rate
change, as dispcc-sm8250 does for its pixel clock sources since
commit acf7a91d0b0e ("clk: qcom: dispcc-sm8250: Enable parents for pixel
clocks").

Fixes: 5db3ae8b33de ("clk: qcom: Add SDM660 Multimedia Clock Controller (MMCC) driver")
Signed-off-by: Fabricio Akio <fabricioakio@gmail.com>
---
Tested on the Motorola Moto X4 (SDM630, payton) with the sdm660-mainline
7.2.y tree, sdm660_defconfig, DRM_MSM=m: without the flag the warning
fires in most boots, with it never. At the stall the RCG reads root-on
and the PLL stopped. With the display built in, clk_disable_unused()
also prepares the PLL under this flag, and some boots then log "DSI PLL
lock failed".
---
 drivers/clk/qcom/mmcc-sdm660.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/qcom/mmcc-sdm660.c b/drivers/clk/qcom/mmcc-sdm660.c
index 9f8b8e29fa0f..bc95d0de75a3 100644
--- a/drivers/clk/qcom/mmcc-sdm660.c
+++ b/drivers/clk/qcom/mmcc-sdm660.c
@@ -984,7 +984,8 @@ static struct clk_rcg2 pclk0_clk_src = {
 		.parent_data = mmcc_xo_dsi0pll_dsi1pll,
 		.num_parents = ARRAY_SIZE(mmcc_xo_dsi0pll_dsi1pll),
 		.ops = &clk_pixel_ops,
-		.flags = CLK_SET_RATE_PARENT | CLK_GET_RATE_NOCACHE,
+		.flags = CLK_SET_RATE_PARENT | CLK_GET_RATE_NOCACHE |
+			 CLK_OPS_PARENT_ENABLE,
 	},
 };
 

---
base-commit: 9f24d789f03b22941b905ded43cb5ff8eea9ce62
change-id: 20261002-sdm660-pclk0-parent-enable-8123c9ac71d8

Best regards,
--  
Fabricio Akio <fabricioakio@gmail.com>