Stop force-selecting PLL-MIPI as TCON0 parent, since it breaks video
output on Pinebook that uses RGB to eDP bridge.
Partially revert commit ca1170b69968 ("clk: sunxi-ng: a64: force
select PLL_MIPI in TCON0 mux"), while still leaving
CLK_SET_RATE_NO_REPARENT flag set, since we do not want the clock to
be reparented.
The issue is that apparently different TCON0 outputs require a different
clock, or the mux might be selecting the output type.
I did an experiment: I manually configured PLL_MIPI and PLL_VIDEO0_2X
to the same clock rate and flipped the switch with devmem. Experiment
clearly showed that whenever PLL_MIPI is selected as TCON0 clock parent,
the video output stops working.
Therefore, TCON0 clock parent corresponding to the output type must be
assigned in the device tree.
Fixes: ca1170b69968 ("clk: sunxi-ng: a64: force select PLL_MIPI in TCON0 mux")
Reviewed-by: Dragan Simic <dsimic@xxxxxxxxxxx>
Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx>
Tested-by: Frank Oltmanns <frank@xxxxxxxxxxxx> # on PinePhone
Tested-by: Stuart Gathman <stuart@xxxxxxxxxxx> # on OG Pinebook
Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
---
drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index 3a7d61c81667..ba1ad267f123 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -535,11 +535,11 @@ static SUNXI_CCU_M_WITH_MUX_GATE(de_clk, "de", de_parents,
CLK_SET_RATE_PARENT);
/*
- * DSI output seems to work only when PLL_MIPI selected. Set it and prevent
- * the mux from reparenting.
+ * Experiments showed that RGB output requires pll-video0-2x, while DSI
+ * requires pll-mipi. It will not work with incorrect clock, the screen will
+ * be blank.
+ * sun50i-a64.dtsi assigns pll-mipi as TCON0 parent by default
*/
-#define SUN50I_A64_TCON0_CLK_REG 0x118
-
static const char * const tcon0_parents[] = { "pll-mipi", "pll-video0-2x" };
static const u8 tcon0_table[] = { 0, 2, };
static SUNXI_CCU_MUX_TABLE_WITH_GATE_CLOSEST(tcon0_clk, "tcon0", tcon0_parents,
@@ -959,11 +959,6 @@ static int sun50i_a64_ccu_probe(struct platform_device *pdev)
writel(0x515, reg + SUN50I_A64_PLL_MIPI_REG);
- /* Set PLL MIPI as parent for TCON0 */
- val = readl(reg + SUN50I_A64_TCON0_CLK_REG);
- val &= ~GENMASK(26, 24);
- writel(val | (0 << 24), reg + SUN50I_A64_TCON0_CLK_REG);
-
ret = devm_sunxi_ccu_probe(&pdev->dev, reg, &sun50i_a64_ccu_desc);
if (ret)
return ret;
--
2.47.1
