linux-kernel - [PATCH 1/3] clk: imx8mq: initialize clock tree earlier

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Date:   Fri, 22 Feb 2019 09:42:22 +0000
From:   Anson Huang <anson.huang@....com>
To:     "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "mturquette@...libre.com" <mturquette@...libre.com>,
        "sboyd@...nel.org" <sboyd@...nel.org>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        Abel Vesa <abel.vesa@....com>,
        "ccaione@...libre.com" <ccaione@...libre.com>,
        "agx@...xcpu.org" <agx@...xcpu.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>
CC:     dl-linux-imx <linux-imx@....com>
Subject: [PATCH 1/3] clk: imx8mq: initialize clock tree earlier

Currently on i.MX8MQ platform, clock driver is probed
later than GPIO driver, and GPIO driver does NOT have
defer probe mechanism since the GPIO clock is optional,
some platforms have GPIO clocks and some are NOT. So
it is an issue that on i.MX8MQ platform, there are GPIO
clocks defined, but due to clock tree is NOT ready during
GPIO driver probe, the GPIO clock management will fail
and cause system hang if GPIO clocks are OFF by default.

This patch changes the i.MX8MQ clock tree initialization
using CLK_OF_DECLARE instead of platform driver model to
make clock tree ready earlier than GPIO driver.

Signed-off-by: Anson Huang <Anson.Huang@....com>
---
 drivers/clk/imx/clk-imx8mq.c | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)

diff --git a/drivers/clk/imx/clk-imx8mq.c b/drivers/clk/imx/clk-imx8mq.c
index 26b57f4..2df1575 100644
--- a/drivers/clk/imx/clk-imx8mq.c
+++ b/drivers/clk/imx/clk-imx8mq.c
@@ -269,10 +269,9 @@ static const char *imx8mq_clko2_sels[] = {"osc_25m", "sys2_pll_200m", "sys1_pll_
 
 static struct clk_onecell_data clk_data;
 
-static int imx8mq_clocks_probe(struct platform_device *pdev)
+static void __init imx8mq_clocks_init(struct device_node *np)
 {
-	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node;
+	struct device_node *anatop_np;
 	void __iomem *base;
 	int err;
 	int i;
@@ -286,10 +285,10 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
 	clks[IMX8MQ_CLK_EXT3] = of_clk_get_by_name(np, "clk_ext3");
 	clks[IMX8MQ_CLK_EXT4] = of_clk_get_by_name(np, "clk_ext4");
 
-	np = of_find_compatible_node(NULL, NULL, "fsl,imx8mq-anatop");
-	base = of_iomap(np, 0);
+	anatop_np = of_find_compatible_node(NULL, NULL, "fsl,imx8mq-anatop");
+	base = of_iomap(anatop_np, 0);
 	if (WARN_ON(!base))
-		return -ENOMEM;
+		return;
 
 	clks[IMX8MQ_ARM_PLL_REF_SEL] = imx_clk_mux("arm_pll_ref_sel", base + 0x28, 16, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
 	clks[IMX8MQ_GPU_PLL_REF_SEL] = imx_clk_mux("gpu_pll_ref_sel", base + 0x18, 16, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
@@ -389,10 +388,9 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
 	clks[IMX8MQ_SYS2_PLL_500M] = imx_clk_fixed_factor("sys2_pll_500m", "sys2_pll_out", 1, 2);
 	clks[IMX8MQ_SYS2_PLL_1000M] = imx_clk_fixed_factor("sys2_pll_1000m", "sys2_pll_out", 1, 1);
 
-	np = dev->of_node;
 	base = of_iomap(np, 0);
 	if (WARN_ON(!base))
-		return -ENOMEM;
+		return;
 
 	/* CORE */
 	clks[IMX8MQ_CLK_A53_SRC] = imx_clk_mux2("arm_a53_src", base + 0x8000, 24, 3, imx8mq_a53_sels, ARRAY_SIZE(imx8mq_a53_sels));
@@ -568,22 +566,5 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
 
 	err = of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 	WARN_ON(err);
-
-	return err;
 }
-
-static const struct of_device_id imx8mq_clk_of_match[] = {
-	{ .compatible = "fsl,imx8mq-ccm" },
-	{ /* Sentinel */ },
-};
-MODULE_DEVICE_TABLE(of, imx8mq_clk_of_match);
-
-
-static struct platform_driver imx8mq_clk_driver = {
-	.probe = imx8mq_clocks_probe,
-	.driver = {
-		.name = "imx8mq-ccm",
-		.of_match_table = of_match_ptr(imx8mq_clk_of_match),
-	},
-};
-module_platform_driver(imx8mq_clk_driver);
+CLK_OF_DECLARE(imx8mq, "fsl,imx8mq-ccm", imx8mq_clocks_init);
-- 
2.7.4