linux-kernel - [PATCH 1/3] clk: sunxi-ng: add mux and pll notifiers for A64 CPU clock

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Message-Id: <20170923001531.14285-2-icenowy@aosc.io>
Date:   Sat, 23 Sep 2017 08:15:29 +0800
From:   Icenowy Zheng <icenowy@...c.io>
To:     Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Chen-Yu Tsai <wens@...e.org>
Cc:     linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-sunxi@...glegroups.com, Icenowy Zheng <icenowy@...c.io>
Subject: [PATCH 1/3] clk: sunxi-ng: add mux and pll notifiers for A64 CPU clock

The A64 PLL_CPU clock has the same instability if some factor changed
without the PLL gated like other SoCs with sun6i-style CCU, e.g. A33,
H3.

Add the mux and pll notifiers for A64 CPU clock to workaround the
problem.

Fixes: c6a0637460c2 ("clk: sunxi-ng: Add A64 clocks")
Signed-off-by: Icenowy Zheng <icenowy@...c.io>
---
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index 2bb4cabf802f..b55fa69dd0c1 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -879,11 +879,26 @@ static const struct sunxi_ccu_desc sun50i_a64_ccu_desc = {
 	.num_resets	= ARRAY_SIZE(sun50i_a64_ccu_resets),
 };
 
+static struct ccu_pll_nb sun50i_a64_pll_cpu_nb = {
+	.common	= &pll_cpux_clk.common,
+	/* copy from pll_cpux_clk */
+	.enable	= BIT(31),
+	.lock	= BIT(28),
+};
+
+static struct ccu_mux_nb sun50i_a64_cpu_nb = {
+	.common		= &cpux_clk.common,
+	.cm		= &cpux_clk.mux,
+	.delay_us	= 1, /* > 8 clock cycles at 24 MHz */
+	.bypass_index	= 1, /* index of 24 MHz oscillator */
+};
+
 static int sun50i_a64_ccu_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	void __iomem *reg;
 	u32 val;
+	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	reg = devm_ioremap_resource(&pdev->dev, res);
@@ -897,7 +912,18 @@ static int sun50i_a64_ccu_probe(struct platform_device *pdev)
 
 	writel(0x515, reg + SUN50I_A64_PLL_MIPI_REG);
 
-	return sunxi_ccu_probe(pdev->dev.of_node, reg, &sun50i_a64_ccu_desc);
+	ret = sunxi_ccu_probe(pdev->dev.of_node, reg, &sun50i_a64_ccu_desc);
+	if (ret)
+		return ret;
+
+	/* Gate then ungate PLL CPU after any rate changes */
+	ccu_pll_notifier_register(&sun50i_a64_pll_cpu_nb);
+
+	/* Reparent CPU during PLL CPU rate changes */
+	ccu_mux_notifier_register(pll_cpux_clk.common.hw.clk,
+				  &sun50i_a64_cpu_nb);
+
+	return 0;
 }
 
 static const struct of_device_id sun50i_a64_ccu_ids[] = {
-- 
2.13.5