clk: Port Linux common clock framework [CCF] for imx6q to U-boot (tag: v5.1.12)

This patch brings the files from Linux kernel (linux-stable/linux-5.1.y
SHA1: 5752b50477da)to provide clocks support as it is used on the Linux
kernel with Common Clock Framework [CCF] setup.

The directory structure has been preserved. The ported code only supports
reading information from PLL, MUX, Divider, etc and enabling/disabling
the clocks USDHCx/ECSPIx depending on used bus. Moreover, it is agnostic
to the alias numbering as the information about the clock is read from the
device tree.

One needs to pay attention to the comments indicating necessary for U-Boot's
driver model changes.

If needed, the code can be extended to support the "set" part of the clock
management.

Signed-off-by: Lukasz Majewski <lukma@denx.de>

drivers/clk/Kconfig

@@ -46,6 +46,20 @@ config CLK_BOSTON
 	help
 	  Enable this to support the clocks
 
+config SPL_CLK_CCF
+	bool "SPL Common Clock Framework [CCF] support "
+	depends on SPL_CLK_IMX6Q
+	help
+	  Enable this option if you want to (re-)use the Linux kernel's Common
+	  Clock Framework [CCF] code in U-Boot's SPL.
+
+config CLK_CCF
+	bool "Common Clock Framework [CCF] support "
+	depends on CLK_IMX6Q
+	help
+	  Enable this option if you want to (re-)use the Linux kernel's Common
+	  Clock Framework [CCF] code in U-Boot's clock driver.
+
 config CLK_STM32F
 	bool "Enable clock driver support for STM32F family"
 	depends on CLK && (STM32F7 || STM32F4)

drivers/clk/Makefile

@@ -7,6 +7,8 @@
 obj-$(CONFIG_$(SPL_TPL_)CLK) += clk-uclass.o
 obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_rate.o
 obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_factor.o
+obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk.o clk-divider.o clk-mux.o
+obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk-fixed-factor.o
 
 obj-y += imx/
 obj-y += tegra/

drivers/clk/clk-divider.c

@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ *
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <dm/uclass.h>
+#include <dm/lists.h>
+#include <dm/device-internal.h>
+#include <linux/clk-provider.h>
+#include <div64.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_CCF_DIVIDER "ccf_clk_divider"
+
+static unsigned int _get_table_div(const struct clk_div_table *table,
+				   unsigned int val)
+{
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->val == val)
+			return clkt->div;
+	return 0;
+}
+
+static unsigned int _get_div(const struct clk_div_table *table,
+			     unsigned int val, unsigned long flags, u8 width)
+{
+	if (flags & CLK_DIVIDER_ONE_BASED)
+		return val;
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		return 1 << val;
+	if (flags & CLK_DIVIDER_MAX_AT_ZERO)
+		return val ? val : clk_div_mask(width) + 1;
+	if (table)
+		return _get_table_div(table, val);
+	return val + 1;
+}
+
+unsigned long divider_recalc_rate(struct clk *hw, unsigned long parent_rate,
+				  unsigned int val,
+				  const struct clk_div_table *table,
+				  unsigned long flags, unsigned long width)
+{
+	unsigned int div;
+
+	div = _get_div(table, val, flags, width);
+	if (!div) {
+		WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
+		     "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
+		     clk_hw_get_name(hw));
+		return parent_rate;
+	}
+
+	return DIV_ROUND_UP_ULL((u64)parent_rate, div);
+}
+
+static ulong clk_divider_recalc_rate(struct clk *clk)
+{
+	struct clk_divider *divider =
+		to_clk_divider(dev_get_clk_ptr(clk->dev));
+	unsigned long parent_rate = clk_get_parent_rate(clk);
+	unsigned int val;
+
+	val = readl(divider->reg) >> divider->shift;
+	val &= clk_div_mask(divider->width);
+
+	return divider_recalc_rate(clk, parent_rate, val, divider->table,
+				   divider->flags, divider->width);
+}
+
+const struct clk_ops clk_divider_ops = {
+	.get_rate = clk_divider_recalc_rate,
+};
+
+static struct clk *_register_divider(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_divider_flags, const struct clk_div_table *table)
+{
+	struct clk_divider *div;
+	struct clk *clk;
+	int ret;
+
+	if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
+		if (width + shift > 16) {
+			pr_warn("divider value exceeds LOWORD field\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* allocate the divider */
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	/* struct clk_divider assignments */
+	div->reg = reg;
+	div->shift = shift;
+	div->width = width;
+	div->flags = clk_divider_flags;
+	div->table = table;
+
+	/* register the clock */
+	clk = &div->clk;
+
+	ret = clk_register(clk, UBOOT_DM_CLK_CCF_DIVIDER, name, parent_name);
+	if (ret) {
+		kfree(div);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+struct clk *clk_register_divider(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_divider_flags)
+{
+	struct clk *clk;
+
+	clk =  _register_divider(dev, name, parent_name, flags, reg, shift,
+				 width, clk_divider_flags, NULL);
+	if (IS_ERR(clk))
+		return ERR_CAST(clk);
+	return clk;
+}
+
+U_BOOT_DRIVER(ccf_clk_divider) = {
+	.name	= UBOOT_DM_CLK_CCF_DIVIDER,
+	.id	= UCLASS_CLK,
+	.ops	= &clk_divider_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/clk-fixed-factor.c

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ *
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ */
+#include <common.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/clk-provider.h>
+#include <div64.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_IMX_FIXED_FACTOR "ccf_clk_fixed_factor"
+
+static ulong clk_factor_recalc_rate(struct clk *clk)
+{
+	struct clk_fixed_factor *fix =
+		to_clk_fixed_factor(dev_get_clk_ptr(clk->dev));
+	unsigned long parent_rate = clk_get_parent_rate(clk);
+	unsigned long long int rate;
+
+	rate = (unsigned long long int)parent_rate * fix->mult;
+	do_div(rate, fix->div);
+	return (ulong)rate;
+}
+
+const struct clk_ops ccf_clk_fixed_factor_ops = {
+	.get_rate = clk_factor_recalc_rate,
+};
+
+struct clk *clk_hw_register_fixed_factor(struct device *dev,
+		const char *name, const char *parent_name, unsigned long flags,
+		unsigned int mult, unsigned int div)
+{
+	struct clk_fixed_factor *fix;
+	struct clk *clk;
+	int ret;
+
+	fix = kzalloc(sizeof(*fix), GFP_KERNEL);
+	if (!fix)
+		return ERR_PTR(-ENOMEM);
+
+	/* struct clk_fixed_factor assignments */
+	fix->mult = mult;
+	fix->div = div;
+	clk = &fix->clk;
+
+	ret = clk_register(clk, UBOOT_DM_CLK_IMX_FIXED_FACTOR, name,
+			   parent_name);
+	if (ret) {
+		kfree(fix);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		unsigned int mult, unsigned int div)
+{
+	struct clk *clk;
+
+	clk = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
+					  div);
+	if (IS_ERR(clk))
+		return ERR_CAST(clk);
+	return clk;
+}
+
+U_BOOT_DRIVER(imx_clk_fixed_factor) = {
+	.name	= UBOOT_DM_CLK_IMX_FIXED_FACTOR,
+	.id	= UCLASS_CLK,
+	.ops	= &ccf_clk_fixed_factor_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/clk-mux.c

@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ *
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * Simple multiplexer clock implementation
+ */
+
+/*
+ * U-Boot CCF porting node:
+ *
+ * The Linux kernel - as of tag: 5.0-rc3 is using also the imx_clk_fixup_mux()
+ * version of CCF mux. It is used on e.g. imx6q to provide fixes (like
+ * imx_cscmr1_fixup) for broken HW.
+ *
+ * At least for IMX6Q (but NOT IMX6QP) it is important when we set the parent
+ * clock.
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/clk-provider.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_CCF_MUX "ccf_clk_mux"
+
+int clk_mux_val_to_index(struct clk *clk, u32 *table, unsigned int flags,
+			 unsigned int val)
+{
+	struct clk_mux *mux = to_clk_mux(clk);
+	int num_parents = mux->num_parents;
+
+	if (table) {
+		int i;
+
+		for (i = 0; i < num_parents; i++)
+			if (table[i] == val)
+				return i;
+		return -EINVAL;
+	}
+
+	if (val && (flags & CLK_MUX_INDEX_BIT))
+		val = ffs(val) - 1;
+
+	if (val && (flags & CLK_MUX_INDEX_ONE))
+		val--;
+
+	if (val >= num_parents)
+		return -EINVAL;
+
+	return val;
+}
+
+static u8 clk_mux_get_parent(struct clk *clk)
+{
+	struct clk_mux *mux = to_clk_mux(clk);
+	u32 val;
+
+	val = readl(mux->reg) >> mux->shift;
+	val &= mux->mask;
+
+	return clk_mux_val_to_index(clk, mux->table, mux->flags, val);
+}
+
+const struct clk_ops clk_mux_ops = {
+		.get_rate = clk_generic_get_rate,
+};
+
+struct clk *clk_hw_register_mux_table(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents,
+		unsigned long flags,
+		void __iomem *reg, u8 shift, u32 mask,
+		u8 clk_mux_flags, u32 *table)
+{
+	struct clk_mux *mux;
+	struct clk *clk;
+	u8 width = 0;
+	int ret;
+
+	if (clk_mux_flags & CLK_MUX_HIWORD_MASK) {
+		width = fls(mask) - ffs(mask) + 1;
+		if (width + shift > 16) {
+			pr_err("mux value exceeds LOWORD field\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* allocate the mux */
+	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return ERR_PTR(-ENOMEM);
+
+	/* U-boot specific assignments */
+	mux->parent_names = parent_names;
+	mux->num_parents = num_parents;
+
+	/* struct clk_mux assignments */
+	mux->reg = reg;
+	mux->shift = shift;
+	mux->mask = mask;
+	mux->flags = clk_mux_flags;
+	mux->table = table;
+
+	clk = &mux->clk;
+
+	/*
+	 * Read the current mux setup - so we assign correct parent.
+	 *
+	 * Changing parent would require changing internals of udevice struct
+	 * for the corresponding clock (to do that define .set_parent() method.
+	 */
+	ret = clk_register(clk, UBOOT_DM_CLK_CCF_MUX, name,
+			   parent_names[clk_mux_get_parent(clk)]);
+	if (ret) {
+		kfree(mux);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+struct clk *clk_register_mux_table(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents,
+		unsigned long flags,
+		void __iomem *reg, u8 shift, u32 mask,
+		u8 clk_mux_flags, u32 *table)
+{
+	struct clk *clk;
+
+	clk = clk_hw_register_mux_table(dev, name, parent_names, num_parents,
+				       flags, reg, shift, mask, clk_mux_flags,
+				       table);
+	if (IS_ERR(clk))
+		return ERR_CAST(clk);
+	return clk;
+}
+
+struct clk *clk_register_mux(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents,
+		unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_mux_flags)
+{
+	u32 mask = BIT(width) - 1;
+
+	return clk_register_mux_table(dev, name, parent_names, num_parents,
+				      flags, reg, shift, mask, clk_mux_flags,
+				      NULL);
+}
+
+U_BOOT_DRIVER(ccf_clk_mux) = {
+	.name	= UBOOT_DM_CLK_CCF_MUX,
+	.id	= UCLASS_CLK,
+	.ops	= &clk_mux_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/clk.c

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <dm/uclass.h>
+#include <dm/lists.h>
+#include <dm/device-internal.h>
+#include <clk.h>
+
+int clk_register(struct clk *clk, const char *drv_name,
+		 const char *name, const char *parent_name)
+{
+	struct udevice *parent;
+	struct driver *drv;
+	int ret;
+
+	ret = uclass_get_device_by_name(UCLASS_CLK, parent_name, &parent);
+	if (ret)
+		printf("%s: UCLASS parent: 0x%p\n", __func__, parent);
+
+	debug("%s: name: %s parent: %s [0x%p]\n", __func__, name, parent->name,
+	      parent);
+
+	drv = lists_driver_lookup_name(drv_name);
+	if (!drv) {
+		printf("%s: %s is not a valid driver name\n",
+		       __func__, drv_name);
+		return -ENOENT;
+	}
+
+	ret = device_bind(parent, drv, name, NULL, -1, &clk->dev);
+	if (ret) {
+		printf("%s: CLK: %s driver bind error [%d]!\n", __func__, name,
+		       ret);
+		return ret;
+	}
+
+	/* Store back pointer to clk from udevice */
+	clk->dev->uclass_priv = clk;
+
+	return 0;
+}
+
+ulong clk_generic_get_rate(struct clk *clk)
+{
+	return clk_get_parent_rate(clk);
+}
+
+const char *clk_hw_get_name(const struct clk *hw)
+{
+	return hw->dev->name;
+}

drivers/clk/imx/Kconfig

@@ -1,3 +1,19 @@
+config SPL_CLK_IMX6Q
+	bool "SPL clock support for i.MX6Q"
+	depends on ARCH_MX6 && SPL
+	select SPL_CLK
+	select SPL_CLK_CCF
+	help
+	  This enables SPL DM/DTS support for clock driver in i.MX6Q platforms.
+
+config CLK_IMX6Q
+	bool "Clock support for i.MX6Q"
+	depends on ARCH_MX6
+	select CLK
+	select CLK_CCF
+	help
+	  This enables DM/DTS support for clock driver in i.MX6Q platforms.
+
 config CLK_IMX8
 	bool "Clock support for i.MX8"
 	depends on ARCH_IMX8

drivers/clk/imx/Makefile

@@ -2,6 +2,8 @@
 #
 # SPDX-License-Identifier: GPL-2.0
 
+obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk-gate2.o clk-pllv3.o clk-pfd.o
+obj-$(CONFIG_$(SPL_TPL_)CLK_IMX6Q) += clk-imx6q.o
 obj-$(CONFIG_CLK_IMX8) += clk-imx8.o
 
 ifdef CONFIG_CLK_IMX8

drivers/clk/imx/clk-gate2.c

@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ *
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Gated clock implementation
+ *
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/clk-provider.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_IMX_GATE2 "imx_clk_gate2"
+
+struct clk_gate2 {
+	struct clk clk;
+	void __iomem	*reg;
+	u8		bit_idx;
+	u8		cgr_val;
+	u8		flags;
+};
+
+#define to_clk_gate2(_clk) container_of(_clk, struct clk_gate2, clk)
+
+static int clk_gate2_enable(struct clk *clk)
+{
+	struct clk_gate2 *gate = to_clk_gate2(dev_get_clk_ptr(clk->dev));
+	u32 reg;
+
+	reg = readl(gate->reg);
+	reg &= ~(3 << gate->bit_idx);
+	reg |= gate->cgr_val << gate->bit_idx;
+	writel(reg, gate->reg);
+
+	return 0;
+}
+
+static int clk_gate2_disable(struct clk *clk)
+{
+	struct clk_gate2 *gate = to_clk_gate2(dev_get_clk_ptr(clk->dev));
+	u32 reg;
+
+	reg = readl(gate->reg);
+	reg &= ~(3 << gate->bit_idx);
+	writel(reg, gate->reg);
+
+	return 0;
+}
+
+static const struct clk_ops clk_gate2_ops = {
+	.enable = clk_gate2_enable,
+	.disable = clk_gate2_disable,
+	.get_rate = clk_generic_get_rate,
+};
+
+struct clk *clk_register_gate2(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 bit_idx, u8 cgr_val,
+		u8 clk_gate2_flags)
+{
+	struct clk_gate2 *gate;
+	struct clk *clk;
+	int ret;
+
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		return ERR_PTR(-ENOMEM);
+
+	gate->reg = reg;
+	gate->bit_idx = bit_idx;
+	gate->cgr_val = cgr_val;
+	gate->flags = clk_gate2_flags;
+
+	clk = &gate->clk;
+
+	ret = clk_register(clk, UBOOT_DM_CLK_IMX_GATE2, name, parent_name);
+	if (ret) {
+		kfree(gate);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+U_BOOT_DRIVER(clk_gate2) = {
+	.name	= UBOOT_DM_CLK_IMX_GATE2,
+	.id	= UCLASS_CLK,
+	.ops	= &clk_gate2_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/imx/clk-imx6q.c

@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+#include <dt-bindings/clock/imx6qdl-clock.h>
+
+#include "clk.h"
+
+static int imx6q_check_id(ulong id)
+{
+	if (id < IMX6QDL_CLK_DUMMY || id >= IMX6QDL_CLK_END) {
+		printf("%s: Invalid clk ID #%lu\n", __func__, id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static ulong imx6q_clk_get_rate(struct clk *clk)
+{
+	struct clk *c;
+	int ret;
+
+	debug("%s(#%lu)\n", __func__, clk->id);
+
+	ret = imx6q_check_id(clk->id);
+	if (ret)
+		return ret;
+
+	ret = clk_get_by_id(clk->id, &c);
+	if (ret)
+		return ret;
+
+	return clk_get_rate(c);
+}
+
+static ulong imx6q_clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	debug("%s(#%lu), rate: %lu\n", __func__, clk->id, rate);
+
+	return rate;
+}
+
+static int __imx6q_clk_enable(struct clk *clk, bool enable)
+{
+	struct clk *c;
+	int ret = 0;
+
+	debug("%s(#%lu) en: %d\n", __func__, clk->id, enable);
+
+	ret = imx6q_check_id(clk->id);
+	if (ret)
+		return ret;
+
+	ret = clk_get_by_id(clk->id, &c);
+	if (ret)
+		return ret;
+
+	if (enable)
+		ret = clk_enable(c);
+	else
+		ret = clk_disable(c);
+
+	return ret;
+}
+
+static int imx6q_clk_disable(struct clk *clk)
+{
+	return __imx6q_clk_enable(clk, 0);
+}
+
+static int imx6q_clk_enable(struct clk *clk)
+{
+	return __imx6q_clk_enable(clk, 1);
+}
+
+static struct clk_ops imx6q_clk_ops = {
+	.set_rate = imx6q_clk_set_rate,
+	.get_rate = imx6q_clk_get_rate,
+	.enable = imx6q_clk_enable,
+	.disable = imx6q_clk_disable,
+};
+
+static const char *const usdhc_sels[] = { "pll2_pfd2_396m", "pll2_pfd0_352m", };
+
+static int imx6q_clk_probe(struct udevice *dev)
+{
+	void *base;
+
+	/* Anatop clocks */
+	base = (void *)ANATOP_BASE_ADDR;
+
+	clk_dm(IMX6QDL_CLK_PLL2,
+	       imx_clk_pllv3(IMX_PLLV3_GENERIC, "pll2_bus", "osc",
+			     base + 0x30, 0x1));
+	clk_dm(IMX6QDL_CLK_PLL3_USB_OTG,
+	       imx_clk_pllv3(IMX_PLLV3_USB, "pll3_usb_otg", "osc",
+			     base + 0x10, 0x3));
+	clk_dm(IMX6QDL_CLK_PLL3_60M,
+	       imx_clk_fixed_factor("pll3_60m",  "pll3_usb_otg",   1, 8));
+	clk_dm(IMX6QDL_CLK_PLL2_PFD0_352M,
+	       imx_clk_pfd("pll2_pfd0_352m", "pll2_bus", base + 0x100, 0));
+	clk_dm(IMX6QDL_CLK_PLL2_PFD2_396M,
+	       imx_clk_pfd("pll2_pfd2_396m", "pll2_bus", base + 0x100, 2));
+
+	/* CCM clocks */
+	base = dev_read_addr_ptr(dev);
+	if (base == (void *)FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	clk_dm(IMX6QDL_CLK_USDHC1_SEL,
+	       imx_clk_mux("usdhc1_sel", base + 0x1c, 16, 1,
+			   usdhc_sels, ARRAY_SIZE(usdhc_sels)));
+	clk_dm(IMX6QDL_CLK_USDHC2_SEL,
+	       imx_clk_mux("usdhc2_sel", base + 0x1c, 17, 1,
+			   usdhc_sels, ARRAY_SIZE(usdhc_sels)));
+	clk_dm(IMX6QDL_CLK_USDHC3_SEL,
+	       imx_clk_mux("usdhc3_sel", base + 0x1c, 18, 1,
+			   usdhc_sels, ARRAY_SIZE(usdhc_sels)));
+	clk_dm(IMX6QDL_CLK_USDHC4_SEL,
+	       imx_clk_mux("usdhc4_sel", base + 0x1c, 19, 1,
+			   usdhc_sels, ARRAY_SIZE(usdhc_sels)));
+
+	clk_dm(IMX6QDL_CLK_USDHC1_PODF,
+	       imx_clk_divider("usdhc1_podf", "usdhc1_sel",
+			       base + 0x24, 11, 3));
+	clk_dm(IMX6QDL_CLK_USDHC2_PODF,
+	       imx_clk_divider("usdhc2_podf", "usdhc2_sel",
+			       base + 0x24, 16, 3));
+	clk_dm(IMX6QDL_CLK_USDHC3_PODF,
+	       imx_clk_divider("usdhc3_podf", "usdhc3_sel",
+			       base + 0x24, 19, 3));
+	clk_dm(IMX6QDL_CLK_USDHC4_PODF,
+	       imx_clk_divider("usdhc4_podf", "usdhc4_sel",
+			       base + 0x24, 22, 3));
+
+	clk_dm(IMX6QDL_CLK_ECSPI_ROOT,
+	       imx_clk_divider("ecspi_root", "pll3_60m", base + 0x38, 19, 6));
+
+	clk_dm(IMX6QDL_CLK_ECSPI1,
+	       imx_clk_gate2("ecspi1", "ecspi_root", base + 0x6c, 0));
+	clk_dm(IMX6QDL_CLK_ECSPI2,
+	       imx_clk_gate2("ecspi2", "ecspi_root", base + 0x6c, 2));
+	clk_dm(IMX6QDL_CLK_ECSPI3,
+	       imx_clk_gate2("ecspi3", "ecspi_root", base + 0x6c, 4));
+	clk_dm(IMX6QDL_CLK_ECSPI4,
+	       imx_clk_gate2("ecspi4", "ecspi_root", base + 0x6c, 6));
+	clk_dm(IMX6QDL_CLK_USDHC1,
+	       imx_clk_gate2("usdhc1", "usdhc1_podf", base + 0x80, 2));
+	clk_dm(IMX6QDL_CLK_USDHC2,
+	       imx_clk_gate2("usdhc2", "usdhc2_podf", base + 0x80, 4));
+	clk_dm(IMX6QDL_CLK_USDHC3,
+	       imx_clk_gate2("usdhc3", "usdhc3_podf", base + 0x80, 6));
+	clk_dm(IMX6QDL_CLK_USDHC4,
+	       imx_clk_gate2("usdhc4", "usdhc4_podf", base + 0x80, 8));
+
+	return 0;
+}
+
+static const struct udevice_id imx6q_clk_ids[] = {
+	{ .compatible = "fsl,imx6q-ccm" },
+	{ },
+};
+
+U_BOOT_DRIVER(imx6q_clk) = {
+	.name = "clk_imx6q",
+	.id = UCLASS_CLK,
+	.of_match = imx6q_clk_ids,
+	.ops = &imx6q_clk_ops,
+	.probe = imx6q_clk_probe,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/imx/clk-pfd.c

@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ *
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ * Copyright 2012 Linaro Ltd.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/clk-provider.h>
+#include <div64.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_IMX_PFD "imx_clk_pfd"
+
+struct clk_pfd {
+	struct clk	clk;
+	void __iomem	*reg;
+	u8		idx;
+};
+
+#define to_clk_pfd(_clk) container_of(_clk, struct clk_pfd, clk)
+
+#define SET	0x4
+#define CLR	0x8
+#define OTG	0xc
+
+static unsigned long clk_pfd_recalc_rate(struct clk *clk)
+{
+	struct clk_pfd *pfd =
+		to_clk_pfd(dev_get_clk_ptr(clk->dev));
+	unsigned long parent_rate = clk_get_parent_rate(clk);
+	u64 tmp = parent_rate;
+	u8 frac = (readl(pfd->reg) >> (pfd->idx * 8)) & 0x3f;
+
+	tmp *= 18;
+	do_div(tmp, frac);
+
+	return tmp;
+}
+
+static const struct clk_ops clk_pfd_ops = {
+	.get_rate	= clk_pfd_recalc_rate,
+};
+
+struct clk *imx_clk_pfd(const char *name, const char *parent_name,
+			void __iomem *reg, u8 idx)
+{
+	struct clk_pfd *pfd;
+	struct clk *clk;
+	int ret;
+
+	pfd = kzalloc(sizeof(*pfd), GFP_KERNEL);
+	if (!pfd)
+		return ERR_PTR(-ENOMEM);
+
+	pfd->reg = reg;
+	pfd->idx = idx;
+
+	/* register the clock */
+	clk = &pfd->clk;
+
+	ret = clk_register(clk, UBOOT_DM_CLK_IMX_PFD, name, parent_name);
+	if (ret) {
+		kfree(pfd);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+U_BOOT_DRIVER(clk_pfd) = {
+	.name	= UBOOT_DM_CLK_IMX_PFD,
+	.id	= UCLASS_CLK,
+	.ops	= &clk_pfd_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/imx/clk-pllv3.c

@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <dm/uclass.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_IMX_PLLV3 "imx_clk_pllv3"
+
+struct clk_pllv3 {
+	struct clk	clk;
+	void __iomem	*base;
+	u32		div_mask;
+	u32		div_shift;
+};
+
+#define to_clk_pllv3(_clk) container_of(_clk, struct clk_pllv3, clk)
+
+static ulong clk_pllv3_get_rate(struct clk *clk)
+{
+	struct clk_pllv3 *pll = to_clk_pllv3(dev_get_clk_ptr(clk->dev));
+	unsigned long parent_rate = clk_get_parent_rate(clk);
+
+	u32 div = (readl(pll->base) >> pll->div_shift) & pll->div_mask;
+
+	return (div == 1) ? parent_rate * 22 : parent_rate * 20;
+}
+
+static const struct clk_ops clk_pllv3_generic_ops = {
+	.get_rate       = clk_pllv3_get_rate,
+};
+
+struct clk *imx_clk_pllv3(enum imx_pllv3_type type, const char *name,
+			  const char *parent_name, void __iomem *base,
+			  u32 div_mask)
+{
+	struct clk_pllv3 *pll;
+	struct clk *clk;
+	char *drv_name;
+	int ret;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	switch (type) {
+	case IMX_PLLV3_GENERIC:
+	case IMX_PLLV3_USB:
+		drv_name = UBOOT_DM_CLK_IMX_PLLV3;
+		break;
+	default:
+		kfree(pll);
+		return ERR_PTR(-ENOTSUPP);
+	}
+
+	pll->base = base;
+	pll->div_mask = div_mask;
+	clk = &pll->clk;
+
+	ret = clk_register(clk, drv_name, name, parent_name);
+	if (ret) {
+		kfree(pll);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+U_BOOT_DRIVER(clk_pllv3_generic) = {
+	.name	= UBOOT_DM_CLK_IMX_PLLV3,
+	.id	= UCLASS_CLK,
+	.ops	= &clk_pllv3_generic_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/imx/clk.h

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ */
+#ifndef __MACH_IMX_CLK_H
+#define __MACH_IMX_CLK_H
+
+#include <linux/clk-provider.h>
+
+enum imx_pllv3_type {
+	IMX_PLLV3_GENERIC,
+	IMX_PLLV3_SYS,
+	IMX_PLLV3_USB,
+	IMX_PLLV3_USB_VF610,
+	IMX_PLLV3_AV,
+	IMX_PLLV3_ENET,
+	IMX_PLLV3_ENET_IMX7,
+	IMX_PLLV3_SYS_VF610,
+	IMX_PLLV3_DDR_IMX7,
+};
+
+struct clk *clk_register_gate2(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 bit_idx, u8 cgr_val,
+		u8 clk_gate_flags);
+
+struct clk *imx_clk_pllv3(enum imx_pllv3_type type, const char *name,
+			  const char *parent_name, void __iomem *base,
+			  u32 div_mask);
+
+static inline struct clk *imx_clk_gate2(const char *name, const char *parent,
+					void __iomem *reg, u8 shift)
+{
+	return clk_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
+			shift, 0x3, 0);
+}
+
+static inline struct clk *imx_clk_fixed_factor(const char *name,
+		const char *parent, unsigned int mult, unsigned int div)
+{
+	return clk_register_fixed_factor(NULL, name, parent,
+			CLK_SET_RATE_PARENT, mult, div);
+}
+
+static inline struct clk *imx_clk_divider(const char *name, const char *parent,
+		void __iomem *reg, u8 shift, u8 width)
+{
+	return clk_register_divider(NULL, name, parent, CLK_SET_RATE_PARENT,
+			reg, shift, width, 0);
+}
+
+struct clk *imx_clk_pfd(const char *name, const char *parent_name,
+			void __iomem *reg, u8 idx);
+
+struct clk *imx_clk_fixup_mux(const char *name, void __iomem *reg,
+			      u8 shift, u8 width, const char * const *parents,
+			      int num_parents, void (*fixup)(u32 *val));
+
+static inline struct clk *imx_clk_mux(const char *name, void __iomem *reg,
+			u8 shift, u8 width, const char * const *parents,
+			int num_parents)
+{
+	return clk_register_mux(NULL, name, parents, num_parents,
+			CLK_SET_RATE_NO_REPARENT, reg, shift,
+			width, 0);
+}
+
+#endif /* __MACH_IMX_CLK_H */

include/linux/clk-provider.h

@@ -9,6 +9,115 @@
 #ifndef __LINUX_CLK_PROVIDER_H
 #define __LINUX_CLK_PROVIDER_H
 
+static inline void clk_dm(ulong id, struct clk *clk)
+{
+	if (!IS_ERR(clk))
+		clk->id = id;
+}
+
+/*
+ * flags used across common struct clk.  these flags should only affect the
+ * top-level framework.  custom flags for dealing with hardware specifics
+ * belong in struct clk_foo
+ *
+ * Please update clk_flags[] in drivers/clk/clk.c when making changes here!
+ */
+#define CLK_SET_RATE_GATE	BIT(0) /* must be gated across rate change */
+#define CLK_SET_PARENT_GATE	BIT(1) /* must be gated across re-parent */
+#define CLK_SET_RATE_PARENT	BIT(2) /* propagate rate change up one level */
+#define CLK_IGNORE_UNUSED	BIT(3) /* do not gate even if unused */
+				/* unused */
+#define CLK_IS_BASIC		BIT(5) /* Basic clk, can't do a to_clk_foo() */
+#define CLK_GET_RATE_NOCACHE	BIT(6) /* do not use the cached clk rate */
+#define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */
+#define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */
+#define CLK_RECALC_NEW_RATES	BIT(9) /* recalc rates after notifications */
+#define CLK_SET_RATE_UNGATE	BIT(10) /* clock needs to run to set rate */
+#define CLK_IS_CRITICAL		BIT(11) /* do not gate, ever */
+/* parents need enable during gate/ungate, set rate and re-parent */
+#define CLK_OPS_PARENT_ENABLE	BIT(12)
+/* duty cycle call may be forwarded to the parent clock */
+#define CLK_DUTY_CYCLE_PARENT	BIT(13)
+
+#define CLK_MUX_INDEX_ONE		BIT(0)
+#define CLK_MUX_INDEX_BIT		BIT(1)
+#define CLK_MUX_HIWORD_MASK		BIT(2)
+#define CLK_MUX_READ_ONLY		BIT(3) /* mux can't be changed */
+#define CLK_MUX_ROUND_CLOSEST		BIT(4)
+
+struct clk_mux {
+	struct clk	clk;
+	void __iomem	*reg;
+	u32		*table;
+	u32		mask;
+	u8		shift;
+	u8		flags;
+
+	/*
+	 * Fields from struct clk_init_data - this struct has been
+	 * omitted to avoid too deep level of CCF for bootloader
+	 */
+	const char	* const *parent_names;
+	u8		num_parents;
+};
+
+#define to_clk_mux(_clk) container_of(_clk, struct clk_mux, clk)
+
+struct clk_div_table {
+	unsigned int	val;
+	unsigned int	div;
+};
+
+struct clk_divider {
+	struct clk	clk;
+	void __iomem	*reg;
+	u8		shift;
+	u8		width;
+	u8		flags;
+	const struct clk_div_table	*table;
+};
+
+#define clk_div_mask(width)	((1 << (width)) - 1)
+#define to_clk_divider(_clk) container_of(_clk, struct clk_divider, clk)
+
+#define CLK_DIVIDER_ONE_BASED		BIT(0)
+#define CLK_DIVIDER_POWER_OF_TWO	BIT(1)
+#define CLK_DIVIDER_ALLOW_ZERO		BIT(2)
+#define CLK_DIVIDER_HIWORD_MASK		BIT(3)
+#define CLK_DIVIDER_ROUND_CLOSEST	BIT(4)
+#define CLK_DIVIDER_READ_ONLY		BIT(5)
+#define CLK_DIVIDER_MAX_AT_ZERO		BIT(6)
+
+struct clk_fixed_factor {
+	struct clk	clk;
+	unsigned int	mult;
+	unsigned int	div;
+};
+
+#define to_clk_fixed_factor(_clk) container_of(_clk, struct clk_fixed_factor,\
+					       clk)
+
+int clk_register(struct clk *clk, const char *drv_name, const char *name,
+		 const char *parent_name);
+
+struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		unsigned int mult, unsigned int div);
+
+struct clk *clk_register_divider(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_divider_flags);
+
+struct clk *clk_register_mux(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents,
+		unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_mux_flags);
+
+const char *clk_hw_get_name(const struct clk *hw);
+ulong clk_generic_get_rate(struct clk *clk);
+
 static inline struct clk *dev_get_clk_ptr(struct udevice *dev)
 {
 	return (struct clk *)dev_get_uclass_priv(dev);