[PATCH 2/3] clk: sunxi-ng: a64: keep tcon0 clock rate when pll-video0's rate changes

[Frank Oltmanns]

From: Icenowy Zheng <icenowy at aosc.io>

Notify TCON0 clock (and in consequence PLL-MIPI by CLK_SET_RATE_PARENT)
to reset when PLL-Video0 changes (because of HDMI PHY clk which is a
child of PLL-Video0 and has CLK_SET_RATE_PARENT set). In this way we can
get clock tree to satisfy both pipelines.
---
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index ef567775fc95..93beedb0428e 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -943,6 +943,17 @@ static struct ccu_mux_nb sun50i_a64_cpu_nb = {
 	.bypass_index	= 1, /* index of 24 MHz oscillator */
 };
 
+/*
+ * Since PLL-Video0 is an ancestor of both tcon0 and HDMI PYH, tcon0 clock will
+ * conflict with HDMI PHY clock which is on another display pipeline.
+ *
+ * Therefore, a notifier is required to restore the rate of TCON0 when the rate
+ * of PLL-Video0 changed.
+ */
+static struct ccu_rate_reset_nb sun50i_a64_pll_video0_reset_tcon0_nb = {
+	.common		= &pll_video0_clk.common,
+};
+
 static int sun50i_a64_ccu_probe(struct platform_device *pdev)
 {
 	void __iomem *reg;
@@ -978,6 +989,10 @@ static int sun50i_a64_ccu_probe(struct platform_device *pdev)
 	ccu_mux_notifier_register(pll_cpux_clk.common.hw.clk,
 				  &sun50i_a64_cpu_nb);
 
+	/* Reset the rate of TCON0 clock when PLL-VIDEO0 is changed */
+	sun50i_a64_pll_video0_reset_tcon0_nb.target_clk = tcon0_clk.common.hw.clk;
+	ccu_rate_reset_notifier_register(&sun50i_a64_pll_video0_reset_tcon0_nb);
+
 	return 0;
 }
 

-- 
2.41.0