[PATCH v2 1/2] clk: meson: meson8b: register the clock controller early

[martin.blumenstingl@googlemail.com (Martin Blumenstingl)]

Until now only the reset controller (part of the clock controller
register space) was registered early in the boot process, while the
clock controller itself was registered later on.
However, some parts of the SoC are initialized early in the boot process,
such as the SRAM and the TWD timer. The bootloader already enables these
clocks so we didn't see any issues so far.

Register the clock controller early so other drivers (such as the SRAM
and TWD timer) can use the clocks early in the boot process. Now that we
don't have a "split" initialization process anymore we can also switch
from CLK_OF_DECLARE_DRIVER (which allows registering a part of the clock
controller early, an another part as platform device) to CLK_OF_DECLARE
(which only supports early initialization).

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 drivers/clk/meson/meson8b.c | 97 +++++++++++++------------------------
 1 file changed, 34 insertions(+), 63 deletions(-)

diff --git a/drivers/clk/meson/meson8b.c b/drivers/clk/meson/meson8b.c
index 045d72e408f8..abdcfe54f6a0 100644
--- a/drivers/clk/meson/meson8b.c
+++ b/drivers/clk/meson/meson8b.c
@@ -11,7 +11,6 @@
 #include <linux/clk-provider.h>
 #include <linux/init.h>
 #include <linux/of_address.h>
-#include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
 #include <linux/regmap.h>
@@ -22,8 +21,6 @@
 
 static DEFINE_SPINLOCK(meson_clk_lock);
 
-static void __iomem *clk_base;
-
 struct meson8b_clk_reset {
 	struct reset_controller_dev reset;
 	void __iomem *base;
@@ -1123,62 +1120,12 @@ static const struct regmap_config clkc_regmap_config = {
 	.reg_stride     = 4,
 };
 
-static int meson8b_clkc_probe(struct platform_device *pdev)
-{
-	int ret, i;
-	struct device *dev = &pdev->dev;
-	struct regmap *map;
-
-	if (!clk_base)
-		return -ENXIO;
-
-	map = devm_regmap_init_mmio(dev, clk_base, &clkc_regmap_config);
-	if (IS_ERR(map))
-		return PTR_ERR(map);
-
-	/* Populate regmap for the regmap backed clocks */
-	for (i = 0; i < ARRAY_SIZE(meson8b_clk_regmaps); i++)
-		meson8b_clk_regmaps[i]->map = map;
-
-	/*
-	 * register all clks
-	 * CLKID_UNUSED = 0, so skip it and start with CLKID_XTAL = 1
-	 */
-	for (i = CLKID_XTAL; i < CLK_NR_CLKS; i++) {
-		/* array might be sparse */
-		if (!meson8b_hw_onecell_data.hws[i])
-			continue;
-
-		ret = devm_clk_hw_register(dev, meson8b_hw_onecell_data.hws[i]);
-		if (ret)
-			return ret;
-	}
-
-	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
-					   &meson8b_hw_onecell_data);
-}
-
-static const struct of_device_id meson8b_clkc_match_table[] = {
-	{ .compatible = "amlogic,meson8-clkc" },
-	{ .compatible = "amlogic,meson8b-clkc" },
-	{ .compatible = "amlogic,meson8m2-clkc" },
-	{ }
-};
-
-static struct platform_driver meson8b_driver = {
-	.probe		= meson8b_clkc_probe,
-	.driver		= {
-		.name	= "meson8b-clkc",
-		.of_match_table = meson8b_clkc_match_table,
-	},
-};
-
-builtin_platform_driver(meson8b_driver);
-
-static void __init meson8b_clkc_reset_init(struct device_node *np)
+static void __init meson8b_clkc_init(struct device_node *np)
 {
 	struct meson8b_clk_reset *rstc;
-	int ret;
+	void __iomem *clk_base;
+	struct regmap *map;
+	int i, ret;
 
 	/* Generic clocks, PLLs and some of the reset-bits */
 	clk_base = of_iomap(np, 1);
@@ -1187,6 +1134,10 @@ static void __init meson8b_clkc_reset_init(struct device_node *np)
 		return;
 	}
 
+	map = regmap_init_mmio(NULL, clk_base, &clkc_regmap_config);
+	if (IS_ERR(map))
+		return;
+
 	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
 	if (!rstc)
 		return;
@@ -1202,11 +1153,31 @@ static void __init meson8b_clkc_reset_init(struct device_node *np)
 		       __func__, ret);
 		return;
 	}
+
+	/* Populate regmap for the regmap backed clocks */
+	for (i = 0; i < ARRAY_SIZE(meson8b_clk_regmaps); i++)
+		meson8b_clk_regmaps[i]->map = map;
+
+	/*
+	 * register all clks
+	 * CLKID_UNUSED = 0, so skip it and start with CLKID_XTAL = 1
+	 */
+	for (i = CLKID_XTAL; i < CLK_NR_CLKS; i++) {
+		/* array might be sparse */
+		if (!meson8b_hw_onecell_data.hws[i])
+			continue;
+
+		ret = clk_hw_register(NULL, meson8b_hw_onecell_data.hws[i]);
+		if (ret)
+			return;
+	}
+
+	ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get,
+				     &meson8b_hw_onecell_data);
+	if (ret)
+		pr_err("%s: failed to register clock provider\n", __func__);
 }
 
-CLK_OF_DECLARE_DRIVER(meson8_clkc, "amlogic,meson8-clkc",
-		      meson8b_clkc_reset_init);
-CLK_OF_DECLARE_DRIVER(meson8b_clkc, "amlogic,meson8b-clkc",
-		      meson8b_clkc_reset_init);
-CLK_OF_DECLARE_DRIVER(meson8m2_clkc, "amlogic,meson8m2-clkc",
-		      meson8b_clkc_reset_init);
+CLK_OF_DECLARE(meson8_clkc, "amlogic,meson8-clkc", meson8b_clkc_init);
+CLK_OF_DECLARE(meson8b_clkc, "amlogic,meson8b-clkc", meson8b_clkc_init);
+CLK_OF_DECLARE(meson8m2_clkc, "amlogic,meson8m2-clkc", meson8b_clkc_init);
-- 
2.18.0