linux-kernel - [PATCH AUTOSEL for 4.9 08/56] clk: sunxi-ng: fix PLL

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Message-ID: <20171122222246.19618-15-alexander.levin@verizon.com>
Date:   Wed, 22 Nov 2017 22:23:27 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Icenowy Zheng <icenowy@...c.xyz>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.9 08/56] clk: sunxi-ng: fix PLL_CPUX adjusting
 on A33

From: Icenowy Zheng <icenowy@...c.xyz>

[ Upstream commit 790d929b540661945d1c70652ffb602c5c06ad85 ]

When adjusting PLL_CPUX on A33, the PLL is temporarily driven too high,
and the system hangs.

Add a notifier to avoid this situation by temporarily switching to a
known stable 24 MHz oscillator.

Signed-off-by: Icenowy Zheng <icenowy@...c.xyz>
Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/clk/sunxi-ng/ccu-sun8i-a33.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
index 9bd1f78a0547..e1dc4e5b34e1 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
@@ -752,6 +752,13 @@ static const struct sunxi_ccu_desc sun8i_a33_ccu_desc = {
 	.num_resets	= ARRAY_SIZE(sun8i_a33_ccu_resets),
 };
 
+static struct ccu_mux_nb sun8i_a33_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 void __init sun8i_a33_ccu_setup(struct device_node *node)
 {
 	void __iomem *reg;
@@ -775,6 +782,9 @@ static void __init sun8i_a33_ccu_setup(struct device_node *node)
 	writel(val, reg + SUN8I_A33_PLL_MIPI_REG);
 
 	sunxi_ccu_probe(node, reg, &sun8i_a33_ccu_desc);
+
+	ccu_mux_notifier_register(pll_cpux_clk.common.hw.clk,
+				  &sun8i_a33_cpu_nb);
 }
 CLK_OF_DECLARE(sun8i_a33_ccu, "allwinner,sun8i-a33-ccu",
 	       sun8i_a33_ccu_setup);
-- 
2.11.0