Merge remote-tracking branch 'agust/next' into next

<<
Switch mpc512x to the common clock framework and adapt mpc512x
drivers to use the new clock driver. Old PPC_CLOCK code is
removed entirely since there are no users any more.
>>

6 files changed, 1317 insertions, 834 deletions

diff --git a/arch/powerpc/platforms/512x/Kconfig b/arch/powerpc/platforms/512x/Kconfig
index fc9c1cbfcb1..5aa3f4b5332 100644
--- a/arch/powerpc/platforms/512x/Kconfig
+++ b/arch/powerpc/platforms/512x/Kconfig
@@ -1,9 +1,9 @@
 config PPC_MPC512x
 	bool "512x-based boards"
 	depends on 6xx
+	select COMMON_CLK
 	select FSL_SOC
 	select IPIC
-	select PPC_CLOCK
 	select PPC_PCI_CHOICE
 	select FSL_PCI if PCI
 	select ARCH_WANT_OPTIONAL_GPIOLIB
diff --git a/arch/powerpc/platforms/512x/Makefile b/arch/powerpc/platforms/512x/Makefile
index 72fb9340e09..01693121a2b 100644
--- a/arch/powerpc/platforms/512x/Makefile
+++ b/arch/powerpc/platforms/512x/Makefile
@@ -1,7 +1,8 @@
 #
 # Makefile for the Freescale PowerPC 512x linux kernel.
 #
-obj-y				+= clock.o mpc512x_shared.o
+obj-$(CONFIG_COMMON_CLK)	+= clock-commonclk.o
+obj-y				+= mpc512x_shared.o
 obj-$(CONFIG_MPC5121_ADS)	+= mpc5121_ads.o mpc5121_ads_cpld.o
 obj-$(CONFIG_MPC512x_GENERIC)	+= mpc512x_generic.o
 obj-$(CONFIG_PDM360NG)		+= pdm360ng.o
diff --git a/arch/powerpc/platforms/512x/clock-commonclk.c b/arch/powerpc/platforms/512x/clock-commonclk.c
new file mode 100644
index 00000000000..6eb614a271f
--- /dev/null
+++ b/arch/powerpc/platforms/512x/clock-commonclk.c
@@ -0,0 +1,1221 @@
+/*
+ * Copyright (C) 2013 DENX Software Engineering
+ *
+ * Gerhard Sittig, <gsi@denx.de>
+ *
+ * common clock driver support for the MPC512x platform
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include <asm/mpc5121.h>
+#include <dt-bindings/clock/mpc512x-clock.h>
+
+#include "mpc512x.h"		/* our public mpc5121_clk_init() API */
+
+/* helpers to keep the MCLK intermediates "somewhere" in our table */
+enum {
+	MCLK_IDX_MUX0,
+	MCLK_IDX_EN0,
+	MCLK_IDX_DIV0,
+	MCLK_MAX_IDX,
+};
+
+#define NR_PSCS			12
+#define NR_MSCANS		4
+#define NR_SPDIFS		1
+#define NR_OUTCLK		4
+#define NR_MCLKS		(NR_PSCS + NR_MSCANS + NR_SPDIFS + NR_OUTCLK)
+
+/* extend the public set of clocks by adding internal slots for management */
+enum {
+	/* arrange for adjacent numbers after the public set */
+	MPC512x_CLK_START_PRIVATE = MPC512x_CLK_LAST_PUBLIC,
+	/* clocks which aren't announced to the public */
+	MPC512x_CLK_DDR,
+	MPC512x_CLK_MEM,
+	MPC512x_CLK_IIM,
+	/* intermediates in div+gate combos or fractional dividers */
+	MPC512x_CLK_DDR_UG,
+	MPC512x_CLK_SDHC_x4,
+	MPC512x_CLK_SDHC_UG,
+	MPC512x_CLK_SDHC2_UG,
+	MPC512x_CLK_DIU_x4,
+	MPC512x_CLK_DIU_UG,
+	MPC512x_CLK_MBX_BUS_UG,
+	MPC512x_CLK_MBX_UG,
+	MPC512x_CLK_MBX_3D_UG,
+	MPC512x_CLK_PCI_UG,
+	MPC512x_CLK_NFC_UG,
+	MPC512x_CLK_LPC_UG,
+	MPC512x_CLK_SPDIF_TX_IN,
+	/* intermediates for the mux+gate+div+mux MCLK generation */
+	MPC512x_CLK_MCLKS_FIRST,
+	MPC512x_CLK_MCLKS_LAST = MPC512x_CLK_MCLKS_FIRST
+				+ NR_MCLKS * MCLK_MAX_IDX,
+	/* internal, symbolic spec for the number of slots */
+	MPC512x_CLK_LAST_PRIVATE,
+};
+
+/* data required for the OF clock provider registration */
+static struct clk *clks[MPC512x_CLK_LAST_PRIVATE];
+static struct clk_onecell_data clk_data;
+
+/* CCM register access */
+static struct mpc512x_ccm __iomem *clkregs;
+static DEFINE_SPINLOCK(clklock);
+
+/* SoC variants {{{ */
+
+/*
+ * tell SoC variants apart as they are rather similar yet not identical,
+ * cache the result in an enum to not repeatedly run the expensive OF test
+ *
+ * MPC5123 is an MPC5121 without the MBX graphics accelerator
+ *
+ * MPC5125 has many more differences: no MBX, no AXE, no VIU, no SPDIF,
+ * no PATA, no SATA, no PCI, two FECs (of different compatibility name),
+ * only 10 PSCs (of different compatibility name), two SDHCs, different
+ * NFC IP block, output clocks, system PLL status query, different CPMF
+ * interpretation, no CFM, different fourth PSC/CAN mux0 input -- yet
+ * those differences can get folded into this clock provider support
+ * code and don't warrant a separate highly redundant implementation
+ */
+
+static enum soc_type {
+	MPC512x_SOC_MPC5121,
+	MPC512x_SOC_MPC5123,
+	MPC512x_SOC_MPC5125,
+} soc;
+
+static void mpc512x_clk_determine_soc(void)
+{
+	if (of_machine_is_compatible("fsl,mpc5121")) {
+		soc = MPC512x_SOC_MPC5121;
+		return;
+	}
+	if (of_machine_is_compatible("fsl,mpc5123")) {
+		soc = MPC512x_SOC_MPC5123;
+		return;
+	}
+	if (of_machine_is_compatible("fsl,mpc5125")) {
+		soc = MPC512x_SOC_MPC5125;
+		return;
+	}
+}
+
+static bool soc_has_mbx(void)
+{
+	if (soc == MPC512x_SOC_MPC5121)
+		return true;
+	return false;
+}
+
+static bool soc_has_axe(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return false;
+	return true;
+}
+
+static bool soc_has_viu(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return false;
+	return true;
+}
+
+static bool soc_has_spdif(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return false;
+	return true;
+}
+
+static bool soc_has_pata(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return false;
+	return true;
+}
+
+static bool soc_has_sata(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return false;
+	return true;
+}
+
+static bool soc_has_pci(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return false;
+	return true;
+}
+
+static bool soc_has_fec2(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return true;
+	return false;
+}
+
+static int soc_max_pscnum(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return 10;
+	return 12;
+}
+
+static bool soc_has_sdhc2(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return true;
+	return false;
+}
+
+static bool soc_has_nfc_5125(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return true;
+	return false;
+}
+
+static bool soc_has_outclk(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return true;
+	return false;
+}
+
+static bool soc_has_cpmf_0_bypass(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return true;
+	return false;
+}
+
+static bool soc_has_mclk_mux0_canin(void)
+{
+	if (soc == MPC512x_SOC_MPC5125)
+		return true;
+	return false;
+}
+
+/* }}} SoC variants */
+/* common clk API wrappers {{{ */
+
+/* convenience wrappers around the common clk API */
+static inline struct clk *mpc512x_clk_fixed(const char *name, int rate)
+{
+	return clk_register_fixed_rate(NULL, name, NULL, CLK_IS_ROOT, rate);
+}
+
+static inline struct clk *mpc512x_clk_factor(
+	const char *name, const char *parent_name,
+	int mul, int div)
+{
+	int clkflags;
+
+	clkflags = CLK_SET_RATE_PARENT;
+	return clk_register_fixed_factor(NULL, name, parent_name, clkflags,
+					 mul, div);
+}
+
+static inline struct clk *mpc512x_clk_divider(
+	const char *name, const char *parent_name, u8 clkflags,
+	u32 __iomem *reg, u8 pos, u8 len, int divflags)
+{
+	return clk_register_divider(NULL, name, parent_name, clkflags,
+				    reg, pos, len, divflags, &clklock);
+}
+
+static inline struct clk *mpc512x_clk_divtable(
+	const char *name, const char *parent_name,
+	u32 __iomem *reg, u8 pos, u8 len,
+	const struct clk_div_table *divtab)
+{
+	u8 divflags;
+
+	divflags = 0;
+	return clk_register_divider_table(NULL, name, parent_name, 0,
+					  reg, pos, len, divflags,
+					  divtab, &clklock);
+}
+
+static inline struct clk *mpc512x_clk_gated(
+	const char *name, const char *parent_name,
+	u32 __iomem *reg, u8 pos)
+{
+	int clkflags;
+
+	clkflags = CLK_SET_RATE_PARENT;
+	return clk_register_gate(NULL, name, parent_name, clkflags,
+				 reg, pos, 0, &clklock);
+}
+
+static inline struct clk *mpc512x_clk_muxed(const char *name,
+	const char **parent_names, int parent_count,
+	u32 __iomem *reg, u8 pos, u8 len)
+{
+	int clkflags;
+	u8 muxflags;
+
+	clkflags = CLK_SET_RATE_PARENT;
+	muxflags = 0;
+	return clk_register_mux(NULL, name,
+				parent_names, parent_count, clkflags,
+				reg, pos, len, muxflags, &clklock);
+}
+
+/* }}} common clk API wrappers */
+
+/* helper to isolate a bit field from a register */
+static inline int get_bit_field(uint32_t __iomem *reg, uint8_t pos, uint8_t len)
+{
+	uint32_t val;
+
+	val = in_be32(reg);
+	val >>= pos;
+	val &= (1 << len) - 1;
+	return val;
+}
+
+/* get the SPMF and translate it into the "sys pll" multiplier */
+static int get_spmf_mult(void)
+{
+	static int spmf_to_mult[] = {
+		68, 1, 12, 16, 20, 24, 28, 32,
+		36, 40, 44, 48, 52, 56, 60, 64,
+	};
+	int spmf;
+
+	spmf = get_bit_field(&clkregs->spmr, 24, 4);
+	return spmf_to_mult[spmf];
+}
+
+/*
+ * get the SYS_DIV value and translate it into a divide factor
+ *
+ * values returned from here are a multiple of the real factor since the
+ * divide ratio is fractional
+ */
+static int get_sys_div_x2(void)
+{
+	static int sysdiv_code_to_x2[] = {
+		4, 5, 6, 7, 8, 9, 10, 14,
+		12, 16, 18, 22, 20, 24, 26, 30,
+		28, 32, 34, 38, 36, 40, 42, 46,
+		44, 48, 50, 54, 52, 56, 58, 62,
+		60, 64, 66,
+	};
+	int divcode;
+
+	divcode = get_bit_field(&clkregs->scfr2, 26, 6);
+	return sysdiv_code_to_x2[divcode];
+}
+
+/*
+ * get the CPMF value and translate it into a multiplier factor
+ *
+ * values returned from here are a multiple of the real factor since the
+ * multiplier ratio is fractional
+ */
+static int get_cpmf_mult_x2(void)
+{
+	static int cpmf_to_mult_x36[] = {
+		/* 0b000 is "times 36" */
+		72, 2, 2, 3, 4, 5, 6, 7,
+	};
+	static int cpmf_to_mult_0by[] = {
+		/* 0b000 is "bypass" */
+		2, 2, 2, 3, 4, 5, 6, 7,
+	};
+
+	int *cpmf_to_mult;
+	int cpmf;
+
+	cpmf = get_bit_field(&clkregs->spmr, 16, 4);
+	if (soc_has_cpmf_0_bypass())
+		cpmf_to_mult = cpmf_to_mult_0by;
+	else
+		cpmf_to_mult = cpmf_to_mult_x36;
+	return cpmf_to_mult[cpmf];
+}
+
+/*
+ * some of the clock dividers do scale in a linear way, yet not all of
+ * their bit combinations are legal; use a divider table to get a
+ * resulting set of applicable divider values
+ */
+
+/* applies to the IPS_DIV, and PCI_DIV values */
+static struct clk_div_table divtab_2346[] = {
+	{ .val = 2, .div = 2, },
+	{ .val = 3, .div = 3, },
+	{ .val = 4, .div = 4, },
+	{ .val = 6, .div = 6, },
+	{ .div = 0, },
+};
+
+/* applies to the MBX_DIV, LPC_DIV, and NFC_DIV values */
+static struct clk_div_table divtab_1234[] = {
+	{ .val = 1, .div = 1, },
+	{ .val = 2, .div = 2, },
+	{ .val = 3, .div = 3, },
+	{ .val = 4, .div = 4, },
+	{ .div = 0, },
+};
+
+static int get_freq_from_dt(char *propname)
+{
+	struct device_node *np;
+	const unsigned int *prop;
+	int val;
+
+	val = 0;
+	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-immr");
+	if (np) {
+		prop = of_get_property(np, propname, NULL);
+		if (prop)
+			val = *prop;
+	    of_node_put(np);
+	}
+	return val;
+}
+
+static void mpc512x_clk_preset_data(void)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(clks); i++)
+		clks[i] = ERR_PTR(-ENODEV);
+}
+
+/*
+ * - receives the "bus frequency" from the caller (that's the IPS clock
+ *   rate, the historical source of clock information)
+ * - fetches the system PLL multiplier and divider values as well as the
+ *   IPS divider value from hardware
+ * - determines the REF clock rate either from the XTAL/OSC spec (if
+ *   there is a device tree node describing the oscillator) or from the
+ *   IPS bus clock (supported for backwards compatibility, such that
+ *   setups without XTAL/OSC specs keep working)
+ * - creates the "ref" clock item in the clock tree, such that
+ *   subsequent code can create the remainder of the hierarchy (REF ->
+ *   SYS -> CSB -> IPS) from the REF clock rate and the returned mul/div
+ *   values
+ */
+static void mpc512x_clk_setup_ref_clock(struct device_node *np, int bus_freq,
+					int *sys_mul, int *sys_div,
+					int *ips_div)
+{
+	struct clk *osc_clk;
+	int calc_freq;
+
+	/* fetch mul/div factors from the hardware */
+	*sys_mul = get_spmf_mult();
+	*sys_mul *= 2;		/* compensate for the fractional divider */
+	*sys_div = get_sys_div_x2();
+	*ips_div = get_bit_field(&clkregs->scfr1, 23, 3);
+
+	/* lookup the oscillator clock for its rate */
+	osc_clk = of_clk_get_by_name(np, "osc");
+
+	/*
+	 * either descend from OSC to REF (and in bypassing verify the
+	 * IPS rate), or backtrack from IPS and multiplier values that
+	 * were fetched from hardware to REF and thus to the OSC value
+	 *
+	 * in either case the REF clock gets created here and the
+	 * remainder of the clock tree can get spanned from there
+	 */
+	if (!IS_ERR(osc_clk)) {
+		clks[MPC512x_CLK_REF] = mpc512x_clk_factor("ref", "osc", 1, 1);
+		calc_freq = clk_get_rate(clks[MPC512x_CLK_REF]);
+		calc_freq *= *sys_mul;
+		calc_freq /= *sys_div;
+		calc_freq /= 2;
+		calc_freq /= *ips_div;
+		if (bus_freq && calc_freq != bus_freq)
+			pr_warn("calc rate %d != OF spec %d\n",
+				calc_freq, bus_freq);
+	} else {
+		calc_freq = bus_freq;	/* start with IPS */
+		calc_freq *= *ips_div;	/* IPS -> CSB */
+		calc_freq *= 2;		/* CSB -> SYS */
+		calc_freq *= *sys_div;	/* SYS -> PLL out */
+		calc_freq /= *sys_mul;	/* PLL out -> REF == OSC */
+		clks[MPC512x_CLK_REF] = mpc512x_clk_fixed("ref", calc_freq);
+	}
+}
+
+/* MCLK helpers {{{ */
+
+/*
+ * helper code for the MCLK subtree setup
+ *
+ * the overview in section 5.2.4 of the MPC5121e Reference Manual rev4
+ * suggests that all instances of the "PSC clock generation" are equal,
+ * and that one might re-use the PSC setup for MSCAN clock generation
+ * (section 5.2.5) as well, at least the logic if not the data for
+ * description
+ *
+ * the details (starting at page 5-20) show differences in the specific
+ * inputs of the first mux stage ("can clk in", "spdif tx"), and the
+ * factual non-availability of the second mux stage (it's present yet
+ * only one input is valid)
+ *
+ * the MSCAN clock related registers (starting at page 5-35) all
+ * reference "spdif clk" at the first mux stage and don't mention any
+ * "can clk" at all, which somehow is unexpected
+ *
+ * TODO re-check the document, and clarify whether the RM is correct in
+ * the overview or in the details, and whether the difference is a
+ * clipboard induced error or results from chip revisions
+ *
+ * it turns out that the RM rev4 as of 2012-06 talks about "can" for the
+ * PSCs while RM rev3 as of 2008-10 talks about "spdif", so I guess that
+ * first a doc update is required which better reflects reality in the
+ * SoC before the implementation should follow while no questions remain
+ */
+
+/*
+ * note that this declaration raises a checkpatch warning, but
+ * it's the very data type dictated by <linux/clk-provider.h>,
+ * "fixing" this warning will break compilation
+ */
+static const char *parent_names_mux0_spdif[] = {
+	"sys", "ref", "psc-mclk-in", "spdif-tx",
+};
+
+static const char *parent_names_mux0_canin[] = {
+	"sys", "ref", "psc-mclk-in", "can-clk-in",
+};
+
+enum mclk_type {
+	MCLK_TYPE_PSC,
+	MCLK_TYPE_MSCAN,
+	MCLK_TYPE_SPDIF,
+	MCLK_TYPE_OUTCLK,
+};
+
+struct mclk_setup_data {
+	enum mclk_type type;
+	bool has_mclk1;
+	const char *name_mux0;
+	const char *name_en0;
+	const char *name_div0;
+	const char *parent_names_mux1[2];
+	const char *name_mclk;
+};
+
+#define MCLK_SETUP_DATA_PSC(id) { \
+	MCLK_TYPE_PSC, 0, \
+	"psc" #id "-mux0", \
+	"psc" #id "-en0", \
+	"psc" #id "_mclk_div", \
+	{ "psc" #id "_mclk_div", "dummy", }, \
+	"psc" #id "_mclk", \
+}
+
+#define MCLK_SETUP_DATA_MSCAN(id) { \
+	MCLK_TYPE_MSCAN, 0, \
+	"mscan" #id "-mux0", \
+	"mscan" #id "-en0", \
+	"mscan" #id "_mclk_div", \
+	{ "mscan" #id "_mclk_div", "dummy", }, \
+	"mscan" #id "_mclk", \
+}
+
+#define MCLK_SETUP_DATA_SPDIF { \
+	MCLK_TYPE_SPDIF, 1, \
+	"spdif-mux0", \
+	"spdif-en0", \
+	"spdif_mclk_div", \
+	{ "spdif_mclk_div", "spdif-rx", }, \
+	"spdif_mclk", \
+}
+
+#define MCLK_SETUP_DATA_OUTCLK(id) { \
+	MCLK_TYPE_OUTCLK, 0, \
+	"out" #id "-mux0", \
+	"out" #id "-en0", \
+	"out" #id "_mclk_div", \
+	{ "out" #id "_mclk_div", "dummy", }, \
+	"out" #id "_clk", \
+}
+
+static struct mclk_setup_data mclk_psc_data[] = {
+	MCLK_SETUP_DATA_PSC(0),
+	MCLK_SETUP_DATA_PSC(1),
+	MCLK_SETUP_DATA_PSC(2),
+	MCLK_SETUP_DATA_PSC(3),
+	MCLK_SETUP_DATA_PSC(4),
+	MCLK_SETUP_DATA_PSC(5),
+	MCLK_SETUP_DATA_PSC(6),
+	MCLK_SETUP_DATA_PSC(7),
+	MCLK_SETUP_DATA_PSC(8),
+	MCLK_SETUP_DATA_PSC(9),
+	MCLK_SETUP_DATA_PSC(10),
+	MCLK_SETUP_DATA_PSC(11),
+};
+
+static struct mclk_setup_data mclk_mscan_data[] = {
+	MCLK_SETUP_DATA_MSCAN(0),
+	MCLK_SETUP_DATA_MSCAN(1),
+	MCLK_SETUP_DATA_MSCAN(2),
+	MCLK_SETUP_DATA_MSCAN(3),
+};
+
+static struct mclk_setup_data mclk_spdif_data[] = {
+	MCLK_SETUP_DATA_SPDIF,
+};
+
+static struct mclk_setup_data mclk_outclk_data[] = {
+	MCLK_SETUP_DATA_OUTCLK(0),
+	MCLK_SETUP_DATA_OUTCLK(1),
+	MCLK_SETUP_DATA_OUTCLK(2),
+	MCLK_SETUP_DATA_OUTCLK(3),
+};
+
+/* setup the MCLK clock subtree of an individual PSC/MSCAN/SPDIF */
+static void mpc512x_clk_setup_mclk(struct mclk_setup_data *entry, size_t idx)
+{
+	size_t clks_idx_pub, clks_idx_int;
+	u32 __iomem *mccr_reg;	/* MCLK control register (mux, en, div) */
+	int div;
+
+	/* derive a few parameters from the component type and index */
+	switch (entry->type) {
+	case MCLK_TYPE_PSC:
+		clks_idx_pub = MPC512x_CLK_PSC0_MCLK + idx;
+		clks_idx_int = MPC512x_CLK_MCLKS_FIRST
+			     + (idx) * MCLK_MAX_IDX;
+		mccr_reg = &clkregs->psc_ccr[idx];
+		break;
+	case MCLK_TYPE_MSCAN:
+		clks_idx_pub = MPC512x_CLK_MSCAN0_MCLK + idx;
+		clks_idx_int = MPC512x_CLK_MCLKS_FIRST
+			     + (NR_PSCS + idx) * MCLK_MAX_IDX;
+		mccr_reg = &clkregs->mscan_ccr[idx];
+		break;
+	case MCLK_TYPE_SPDIF:
+		clks_idx_pub = MPC512x_CLK_SPDIF_MCLK;
+		clks_idx_int = MPC512x_CLK_MCLKS_FIRST
+			     + (NR_PSCS + NR_MSCANS) * MCLK_MAX_IDX;
+		mccr_reg = &clkregs->spccr;
+		break;
+	case MCLK_TYPE_OUTCLK:
+		clks_idx_pub = MPC512x_CLK_OUT0_CLK + idx;
+		clks_idx_int = MPC512x_CLK_MCLKS_FIRST
+			     + (NR_PSCS + NR_MSCANS + NR_SPDIFS + idx)
+			     * MCLK_MAX_IDX;
+		mccr_reg = &clkregs->out_ccr[idx];
+		break;
+	default:
+		return;
+	}
+
+	/*
+	 * this was grabbed from the PPC_CLOCK implementation, which
+	 * enforced a specific MCLK divider while the clock was gated
+	 * during setup (that's a documented hardware requirement)
+	 *
+	 * the PPC_CLOCK implementation might even have violated the
+	 * "MCLK <= IPS" constraint, the fixed divider value of 1
+	 * results in a divider of 2 and thus MCLK = SYS/2 which equals
+	 * CSB which is greater than IPS; the serial port setup may have
+	 * adjusted the divider which the clock setup might have left in
+	 * an undesirable state
+	 *
+	 * initial setup is:
+	 * - MCLK 0 from SYS
+	 * - MCLK DIV such to not exceed the IPS clock
+	 * - MCLK 0 enabled
+	 * - MCLK 1 from MCLK DIV
+	 */
+	div = clk_get_rate(clks[MPC512x_CLK_SYS]);
+	div /= clk_get_rate(clks[MPC512x_CLK_IPS]);
+	out_be32(mccr_reg, (0 << 16));
+	out_be32(mccr_reg, (0 << 16) | ((div - 1) << 17));
+	out_be32(mccr_reg, (1 << 16) | ((div - 1) << 17));
+
+	/*
+	 * create the 'struct clk' items of the MCLK's clock subtree
+	 *
+	 * note that by design we always create all nodes and won't take
+	 * shortcuts here, because
+	 * - the "internal" MCLK_DIV and MCLK_OUT signal in turn are
+	 *   selectable inputs to the CFM while those who "actually use"
+	 *   the PSC/MSCAN/SPDIF (serial drivers et al) need the MCLK
+	 *   for their bitrate
+	 * - in the absence of "aliases" for clocks we need to create
+	 *   individial 'struct clk' items for whatever might get
+	 *   referenced or looked up, even if several of those items are
+	 *   identical from the logical POV (their rate value)
+	 * - for easier future maintenance and for better reflection of
+	 *   the SoC's documentation, it appears appropriate to generate
+	 *   clock items even for those muxers which actually are NOPs
+	 *   (those with two inputs of which one is reserved)
+	 */
+	clks[clks_idx_int + MCLK_IDX_MUX0] = mpc512x_clk_muxed(
+			entry->name_mux0,
+			soc_has_mclk_mux0_canin()
+				? &parent_names_mux0_canin[0]
+				: &parent_names_mux0_spdif[0],
+			ARRAY_SIZE(parent_names_mux0_spdif),
+			mccr_reg, 14, 2);
+	clks[clks_idx_int + MCLK_IDX_EN0] = mpc512x_clk_gated(
+			entry->name_en0, entry->name_mux0,
+			mccr_reg, 16);
+	clks[clks_idx_int + MCLK_IDX_DIV0] = mpc512x_clk_divider(
+			entry->name_div0,
+			entry->name_en0, CLK_SET_RATE_GATE,
+			mccr_reg, 17, 15, 0);
+	if (entry->has_mclk1) {
+		clks[clks_idx_pub] = mpc512x_clk_muxed(
+				entry->name_mclk,
+				&entry->parent_names_mux1[0],
+				ARRAY_SIZE(entry->parent_names_mux1),
+				mccr_reg, 7, 1);
+	} else {
+		clks[clks_idx_pub] = mpc512x_clk_factor(
+				entry->name_mclk,
+				entry->parent_names_mux1[0],
+				1, 1);
+	}
+}
+
+/* }}} MCLK helpers */
+
+static void mpc512x_clk_setup_clock_tree(struct device_node *np, int busfreq)
+{
+	int sys_mul, sys_div, ips_div;
+	int mul, div;
+	size_t mclk_idx;
+	int freq;
+
+	/*
+	 * developer's notes:
+	 * - consider whether to handle clocks which have both gates and
+	 *   dividers via intermediates or by means of composites
+	 * - fractional dividers appear to not map well to composites
+	 *   since they can be seen as a fixed multiplier and an
+	 *   adjustable divider, while composites can only combine at
+	 *   most one of a mux, div, and gate each into one 'struct clk'
+	 *   item
+	 * - PSC/MSCAN/SPDIF clock generation OTOH already is very
+	 *   specific and cannot get mapped to componsites (at least not
+	 *   a single one, maybe two of them, but then some of these
+	 *   intermediate clock signals get referenced elsewhere (e.g.
+	 *   in the clock frequency measurement, CFM) and thus need
+	 *   publicly available names
+	 * - the current source layout appropriately reflects the
+	 *   hardware setup, and it works, so it's questionable whether
+	 *   further changes will result in big enough a benefit
+	 */
+
+	/* regardless of whether XTAL/OSC exists, have REF created */
+	mpc512x_clk_setup_ref_clock(np, busfreq, &sys_mul, &sys_div, &ips_div);
+
+	/* now setup the REF -> SYS -> CSB -> IPS hierarchy */
+	clks[MPC512x_CLK_SYS] = mpc512x_clk_factor("sys", "ref",
+						   sys_mul, sys_div);
+	clks[MPC512x_CLK_CSB] = mpc512x_clk_factor("csb", "sys", 1, 2);
+	clks[MPC512x_CLK_IPS] = mpc512x_clk_divtable("ips", "csb",
+						     &clkregs->scfr1, 23, 3,
+						     divtab_2346);
+	/* now setup anything below SYS and CSB and IPS */
+
+	clks[MPC512x_CLK_DDR_UG] = mpc512x_clk_factor("ddr-ug", "sys", 1, 2);
+
+	/*
+	 * the Reference Manual discusses that for SDHC only even divide
+	 * ratios are supported because clock domain synchronization
+	 * between 'per' and 'ipg' is broken;
+	 * keep the divider's bit 0 cleared (per reset value), and only
+	 * allow to setup the divider's bits 7:1, which results in that
+	 * only even divide ratios can get configured upon rate changes;
+	 * keep the "x4" name because this bit shift hack is an internal
+	 * implementation detail, the "fractional divider with quarters"
+	 * semantics remains
+	 */
+	clks[MPC512x_CLK_SDHC_x4] = mpc512x_clk_factor("sdhc-x4", "csb", 2, 1);
+	clks[MPC512x_CLK_SDHC_UG] = mpc512x_clk_divider("sdhc-ug", "sdhc-x4", 0,
+							&clkregs->scfr2, 1, 7,
+							CLK_DIVIDER_ONE_BASED);
+	if (soc_has_sdhc2()) {
+		clks[MPC512x_CLK_SDHC2_UG] = mpc512x_clk_divider(
+				"sdhc2-ug", "sdhc-x4", 0, &clkregs->scfr2,
+				9, 7, CLK_DIVIDER_ONE_BASED);
+	}
+
+	clks[MPC512x_CLK_DIU_x4] = mpc512x_clk_factor("diu-x4", "csb", 4, 1);
+	clks[MPC512x_CLK_DIU_UG] = mpc512x_clk_divider("diu-ug", "diu-x4", 0,
+						       &clkregs->scfr1, 0, 8,
+						       CLK_DIVIDER_ONE_BASED);
+
+	/*
+	 * the "power architecture PLL" was setup from data which was
+	 * sampled from the reset config word, at this point in time the
+	 * configuration can be considered fixed and read only (i.e. no
+	 * longer adjustable, or no longer in need of adjustment), which
+	 * is why we don't register a PLL here but assume fixed factors
+	 */
+	mul = get_cpmf_mult_x2();
+	div = 2;	/* compensate for the fractional factor */
+	clks[MPC512x_CLK_E300] = mpc512x_clk_factor("e300", "csb", mul, div);
+
+	if (soc_has_mbx()) {
+		clks[MPC512x_CLK_MBX_BUS_UG] = mpc512x_clk_factor(
+				"mbx-bus-ug", "csb", 1, 2);
+		clks[MPC512x_CLK_MBX_UG] = mpc512x_clk_divtable(
+				"mbx-ug", "mbx-bus-ug", &clkregs->scfr1,
+				14, 3, divtab_1234);
+		clks[MPC512x_CLK_MBX_3D_UG] = mpc512x_clk_factor(
+				"mbx-3d-ug", "mbx-ug", 1, 1);
+	}
+	if (soc_has_pci()) {
+		clks[MPC512x_CLK_PCI_UG] = mpc512x_clk_divtable(
+				"pci-ug", "csb", &clkregs->scfr1,
+				20, 3, divtab_2346);
+	}
+	if (soc_has_nfc_5125()) {
+		/*
+		 * XXX TODO implement 5125 NFC clock setup logic,
+		 * with high/low period counters in clkregs->scfr3,
+		 * currently there are no users so it's ENOIMPL
+		 */
+		clks[MPC512x_CLK_NFC_UG] = ERR_PTR(-ENOTSUPP);
+	} else {
+		clks[MPC512x_CLK_NFC_UG] = mpc512x_clk_divtable(
+				"nfc-ug", "ips", &clkregs->scfr1,
+				8, 3, divtab_1234);
+	}
+	clks[MPC512x_CLK_LPC_UG] = mpc512x_clk_divtable("lpc-ug", "ips",
+							&clkregs->scfr1, 11, 3,
+							divtab_1234);
+
+	clks[MPC512x_CLK_LPC] = mpc512x_clk_gated("lpc", "lpc-ug",
+						  &clkregs->sccr1, 30);
+	clks[MPC512x_CLK_NFC] = mpc512x_clk_gated("nfc", "nfc-ug",
+						  &clkregs->sccr1, 29);
+	if (soc_has_pata()) {
+		clks[MPC512x_CLK_PATA] = mpc512x_clk_gated(
+				"pata", "ips", &clkregs->sccr1, 28);
+	}
+	/* for PSCs there is a "registers" gate and a bitrate MCLK subtree */
+	for (mclk_idx = 0; mclk_idx < soc_max_pscnum(); mclk_idx++) {
+		char name[12];
+		snprintf(name, sizeof(name), "psc%d", mclk_idx);
+		clks[MPC512x_CLK_PSC0 + mclk_idx] = mpc512x_clk_gated(
+				name, "ips", &clkregs->sccr1, 27 - mclk_idx);
+		mpc512x_clk_setup_mclk(&mclk_psc_data[mclk_idx], mclk_idx);
+	}
+	clks[MPC512x_CLK_PSC_FIFO] = mpc512x_clk_gated("psc-fifo", "ips",
+						       &clkregs->sccr1, 15);
+	if (soc_has_sata()) {
+		clks[MPC512x_CLK_SATA] = mpc512x_clk_gated(
+				"sata", "ips", &clkregs->sccr1, 14);
+	}
+	clks[MPC512x_CLK_FEC] = mpc512x_clk_gated("fec", "ips",
+						  &clkregs->sccr1, 13);
+	if (soc_has_pci()) {
+		clks[MPC512x_CLK_PCI] = mpc512x_clk_gated(
+				"pci", "pci-ug", &clkregs->sccr1, 11);
+	}
+	clks[MPC512x_CLK_DDR] = mpc512x_clk_gated("ddr", "ddr-ug",
+						  &clkregs->sccr1, 10);
+	if (soc_has_fec2()) {
+		clks[MPC512x_CLK_FEC2] = mpc512x_clk_gated(
+				"fec2", "ips", &clkregs->sccr1, 9);
+	}
+
+	clks[MPC512x_CLK_DIU] = mpc512x_clk_gated("diu", "diu-ug",
+						  &clkregs->sccr2, 31);
+	if (soc_has_axe()) {
+		clks[MPC512x_CLK_AXE] = mpc512x_clk_gated(
+				"axe", "csb", &clkregs->sccr2, 30);
+	}
+	clks[MPC512x_CLK_MEM] = mpc512x_clk_gated("mem", "ips",
+						  &clkregs->sccr2, 29);
+	clks[MPC512x_CLK_USB1] = mpc512x_clk_gated("usb1", "csb",
+						   &clkregs->sccr2, 28);
+	clks[MPC512x_CLK_USB2] = mpc512x_clk_gated("usb2", "csb",
+						   &clkregs->sccr2, 27);
+	clks[MPC512x_CLK_I2C] = mpc512x_clk_gated("i2c", "ips",
+						  &clkregs->sccr2, 26);
+	/* MSCAN differs from PSC with just one gate for multiple components */
+	clks[MPC512x_CLK_BDLC] = mpc512x_clk_gated("bdlc", "ips",
+						   &clkregs->sccr2, 25);
+	for (mclk_idx = 0; mclk_idx < ARRAY_SIZE(mclk_mscan_data); mclk_idx++)
+		mpc512x_clk_setup_mclk(&mclk_mscan_data[mclk_idx], mclk_idx);
+	clks[MPC512x_CLK_SDHC] = mpc512x_clk_gated("sdhc", "sdhc-ug",
+						   &clkregs->sccr2, 24);
+	/* there is only one SPDIF component, which shares MCLK support code */
+	if (soc_has_spdif()) {
+		clks[MPC512x_CLK_SPDIF] = mpc512x_clk_gated(
+				"spdif", "ips", &clkregs->sccr2, 23);
+		mpc512x_clk_setup_mclk(&mclk_spdif_data[0], 0);
+	}
+	if (soc_has_mbx()) {
+		clks[MPC512x_CLK_MBX_BUS] = mpc512x_clk_gated(
+				"mbx-bus", "mbx-bus-ug", &clkregs->sccr2, 22);
+		clks[MPC512x_CLK_MBX] = mpc512x_clk_gated(
+				"mbx", "mbx-ug", &clkregs->sccr2, 21);
+		clks[MPC512x_CLK_MBX_3D] = mpc512x_clk_gated(
+				"mbx-3d", "mbx-3d-ug", &clkregs->sccr2, 20);
+	}
+	clks[MPC512x_CLK_IIM] = mpc512x_clk_gated("iim", "csb",
+						  &clkregs->sccr2, 19);
+	if (soc_has_viu()) {
+		clks[MPC512x_CLK_VIU] = mpc512x_clk_gated(
+				"viu", "csb", &clkregs->sccr2, 18);
+	}
+	if (soc_has_sdhc2()) {
+		clks[MPC512x_CLK_SDHC2] = mpc512x_clk_gated(
+				"sdhc-2", "sdhc2-ug", &clkregs->sccr2, 17);
+	}
+
+	if (soc_has_outclk()) {
+		size_t idx;	/* used as mclk_idx, just to trim line length */
+		for (idx = 0; idx < ARRAY_SIZE(mclk_outclk_data); idx++)
+			mpc512x_clk_setup_mclk(&mclk_outclk_data[idx], idx);
+	}
+
+	/*
+	 * externally provided clocks (when implemented in hardware,
+	 * device tree may specify values which otherwise were unknown)
+	 */
+	freq = get_freq_from_dt("psc_mclk_in");
+	if (!freq)
+		freq = 25000000;
+	clks[MPC512x_CLK_PSC_MCLK_IN] = mpc512x_clk_fixed("psc_mclk_in", freq);
+	if (soc_has_mclk_mux0_canin()) {
+		freq = get_freq_from_dt("can_clk_in");
+		clks[MPC512x_CLK_CAN_CLK_IN] = mpc512x_clk_fixed(
+				"can_clk_in", freq);
+	} else {
+		freq = get_freq_from_dt("spdif_tx_in");
+		clks[MPC512x_CLK_SPDIF_TX_IN] = mpc512x_clk_fixed(
+				"spdif_tx_in", freq);
+		freq = get_freq_from_dt("spdif_rx_in");
+		clks[MPC512x_CLK_SPDIF_TX_IN] = mpc512x_clk_fixed(
+				"spdif_rx_in", freq);
+	}
+
+	/* fixed frequency for AC97, always 24.567MHz */
+	clks[MPC512x_CLK_AC97] = mpc512x_clk_fixed("ac97", 24567000);
+
+	/*
+	 * pre-enable those "internal" clock items which never get
+	 * claimed by any peripheral driver, to not have the clock
+	 * subsystem disable them late at startup
+	 */
+	clk_prepare_enable(clks[MPC512x_CLK_DUMMY]);
+	clk_prepare_enable(clks[MPC512x_CLK_E300]);	/* PowerPC CPU */
+	clk_prepare_enable(clks[MPC512x_CLK_DDR]);	/* DRAM */
+	clk_prepare_enable(clks[MPC512x_CLK_MEM]);	/* SRAM */
+	clk_prepare_enable(clks[MPC512x_CLK_IPS]);	/* SoC periph */
+	clk_prepare_enable(clks[MPC512x_CLK_LPC]);	/* boot media */
+}
+
+/*
+ * registers the set of public clocks (those listed in the dt-bindings/
+ * header file) for OF lookups, keeps the intermediates private to us
+ */
+static void mpc5121_clk_register_of_provider(struct device_node *np)
+{
+	clk_data.clks = clks;
+	clk_data.clk_num = MPC512x_CLK_LAST_PUBLIC + 1;	/* _not_ ARRAY_SIZE() */
+	of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
+}
+
+/*
+ * temporary support for the period of time between introduction of CCF
+ * support and the adjustment of peripheral drivers to OF based lookups
+ */
+static void mpc5121_clk_provide_migration_support(void)
+{
+
+	/*
+	 * pre-enable those clock items which are not yet appropriately
+	 * acquired by their peripheral driver
+	 *
+	 * the PCI clock cannot get acquired by its peripheral driver,
+	 * because for this platform the driver won't probe(), instead
+	 * initialization is done from within the .setup_arch() routine
+	 * at a point in time where the clock provider has not been
+	 * setup yet and thus isn't available yet
+	 *
+	 * so we "pre-enable" the clock here, to not have the clock
+	 * subsystem automatically disable this item in a late init call
+	 *
+	 * this PCI clock pre-enable workaround only applies when there
+	 * are device tree nodes for PCI and thus the peripheral driver
+	 * has attached to bridges, otherwise the PCI clock remains
+	 * unused and so it gets disabled
+	 */
+	clk_prepare_enable(clks[MPC512x_CLK_PSC3_MCLK]);/* serial console */
+	if (of_find_compatible_node(NULL, "pci", "fsl,mpc5121-pci"))
+		clk_prepare_enable(clks[MPC512x_CLK_PCI]);
+}
+
+/*
+ * those macros are not exactly pretty, but they encapsulate a lot
+ * of copy'n'paste heavy code which is even more ugly, and reduce
+ * the potential for inconsistencies in those many code copies
+ */
+#define FOR_NODES(compatname) \
+	for_each_compatible_node(np, NULL, compatname)
+
+#define NODE_PREP do { \
+	of_address_to_resource(np, 0, &res); \
+	snprintf(devname, sizeof(devname), "%08x.%s", res.start, np->name); \
+} while (0)
+
+#define NODE_CHK(clkname, clkitem, regnode, regflag) do { \
+	struct clk *clk; \
+	clk = of_clk_get_by_name(np, clkname); \
+	if (IS_ERR(clk)) { \
+		clk = clkitem; \
+		clk_register_clkdev(clk, clkname, devname); \
+		if (regnode) \
+			clk_register_clkdev(clk, clkname, np->name); \
+		did_register |= DID_REG_ ## regflag; \
+		pr_debug("clock alias name '%s' for dev '%s' pointer %p\n", \
+			 clkname, devname, clk); \
+	} else { \
+		clk_put(clk); \
+	} \
+} while (0)
+
+/*
+ * register source code provided fallback results for clock lookups,
+ * these get consulted when OF based clock lookup fails (that is in the
+ * case of not yet adjusted device tree data, where clock related specs
+ * are missing)
+ */
+static void mpc5121_clk_provide_backwards_compat(void)
+{
+	enum did_reg_flags {
+		DID_REG_PSC	= BIT(0),
+		DID_REG_PSCFIFO	= BIT(1),
+		DID_REG_NFC	= BIT(2),
+		DID_REG_CAN	= BIT(3),
+		DID_REG_I2C	= BIT(4),
+		DID_REG_DIU	= BIT(5),
+		DID_REG_VIU	= BIT(6),
+		DID_REG_FEC	= BIT(7),
+		DID_REG_USB	= BIT(8),
+		DID_REG_PATA	= BIT(9),
+	};
+
+	int did_register;
+	struct device_node *np;
+	struct resource res;
+	int idx;
+	char devname[32];
+
+	did_register = 0;
+
+	FOR_NODES(mpc512x_select_psc_compat()) {
+		NODE_PREP;
+		idx = (res.start >> 8) & 0xf;
+		NODE_CHK("ipg", clks[MPC512x_CLK_PSC0 + idx], 0, PSC);
+		NODE_CHK("mclk", clks[MPC512x_CLK_PSC0_MCLK + idx], 0, PSC);
+	}
+
+	FOR_NODES("fsl,mpc5121-psc-fifo") {
+		NODE_PREP;
+		NODE_CHK("ipg", clks[MPC512x_CLK_PSC_FIFO], 1, PSCFIFO);
+	}
+
+	FOR_NODES("fsl,mpc5121-nfc") {
+		NODE_PREP;
+		NODE_CHK("ipg", clks[MPC512x_CLK_NFC], 0, NFC);
+	}
+
+	FOR_NODES("fsl,mpc5121-mscan") {
+		NODE_PREP;
+		idx = 0;
+		idx += (res.start & 0x2000) ? 2 : 0;
+		idx += (res.start & 0x0080) ? 1 : 0;
+		NODE_CHK("ipg", clks[MPC512x_CLK_BDLC], 0, CAN);
+		NODE_CHK("mclk", clks[MPC512x_CLK_MSCAN0_MCLK + idx], 0, CAN);
+	}
+
+	/*
+	 * do register the 'ips', 'sys', and 'ref' names globally
+	 * instead of inside each individual CAN node, as there is no
+	 * potential for a name conflict (in contrast to 'ipg' and 'mclk')
+	 */
+	if (did_register & DID_REG_CAN) {
+		clk_register_clkdev(clks[MPC512x_CLK_IPS], "ips", NULL);
+		clk_register_clkdev(clks[MPC512x_CLK_SYS], "sys", NULL);
+		clk_register_clkdev(clks[MPC512x_CLK_REF], "ref", NULL);
+	}
+
+	FOR_NODES("fsl,mpc5121-i2c") {
+		NODE_PREP;
+		NODE_CHK("ipg", clks[MPC512x_CLK_I2C], 0, I2C);
+	}
+
+	/*
+	 * workaround for the fact that the I2C driver does an "anonymous"
+	 * lookup (NULL name spec, which yields the first clock spec) for
+	 * which we cannot register an alias -- a _global_ 'ipg' alias that
+	 * is not bound to any device name and returns the I2C clock item
+	 * is not a good idea
+	 *
+	 * so we have the lookup in the peripheral driver fail, which is
+	 * silent and non-fatal, and pre-enable the clock item here such
+	 * that register access is possible
+	 *
+	 * see commit b3bfce2b "i2c: mpc: cleanup clock API use" for
+	 * details, adjusting s/NULL/"ipg"/ in i2c-mpc.c would make this
+	 * workaround obsolete
+	 */
+	if (did_register & DID_REG_I2C)
+		clk_prepare_enable(clks[MPC512x_CLK_I2C]);
+
+	FOR_NODES("fsl,mpc5121-diu") {
+		NODE_PREP;
+		NODE_CHK("ipg", clks[MPC512x_CLK_DIU], 1, DIU);
+	}
+
+	FOR_NODES("fsl,mpc5121-viu") {
+		NODE_PREP;
+		NODE_CHK("ipg", clks[MPC512x_CLK_VIU], 0, VIU);
+	}
+
+	/*
+	 * note that 2771399a "fs_enet: cleanup clock API use" did use the
+	 * "per" string for the clock lookup in contrast to the "ipg" name
+	 * which most other nodes are using -- this is not a fatal thing
+	 * but just something to keep in mind when doing compatibility
+	 * registration, it's a non-issue with up-to-date device tree data
+	 */
+	FOR_NODES("fsl,mpc5121-fec") {
+		NODE_PREP;
+		NODE_CHK("per", clks[MPC512x_CLK_FEC], 0, FEC);
+	}
+	FOR_NODES("fsl,mpc5121-fec-mdio") {
+		NODE_PREP;
+		NODE_CHK("per", clks[MPC512x_CLK_FEC], 0, FEC);
+	}
+	/*
+	 * MPC5125 has two FECs: FEC1 at 0x2800, FEC2 at 0x4800;
+	 * the clock items don't "form an array" since FEC2 was
+	 * added only later and was not allowed to shift all other
+	 * clock item indices, so the numbers aren't adjacent
+	 */
+	FOR_NODES("fsl,mpc5125-fec") {
+		NODE_PREP;
+		if (res.start & 0x4000)
+			idx = MPC512x_CLK_FEC2;
+		else
+			idx = MPC512x_CLK_FEC;
+		NODE_CHK("per", clks[idx], 0, FEC);
+	}
+
+	FOR_NODES("fsl,mpc5121-usb2-dr") {
+		NODE_PREP;
+		idx = (res.start & 0x4000) ? 1 : 0;
+		NODE_CHK("ipg", clks[MPC512x_CLK_USB1 + idx], 0, USB);
+	}
+
+	FOR_NODES("fsl,mpc5121-pata") {
+		NODE_PREP;
+		NODE_CHK("ipg", clks[MPC512x_CLK_PATA], 0, PATA);
+	}
+
+	/*
+	 * try to collapse diagnostics into a single line of output yet
+	 * provide a full list of what is missing, to avoid noise in the
+	 * absence of up-to-date device tree data -- backwards
+	 * compatibility to old DTBs is a requirement, updates may be
+	 * desirable or preferrable but are not at all mandatory
+	 */
+	if (did_register) {
+		pr_notice("device tree lacks clock specs, adding fallbacks (0x%x,%s%s%s%s%s%s%s%s%s%s)\n",
+			  did_register,
+			  (did_register & DID_REG_PSC) ? " PSC" : "",
+			  (did_register & DID_REG_PSCFIFO) ? " PSCFIFO" : "",
+			  (did_register & DID_REG_NFC) ? " NFC" : "",
+			  (did_register & DID_REG_CAN) ? " CAN" : "",
+			  (did_register & DID_REG_I2C) ? " I2C" : "",
+			  (did_register & DID_REG_DIU) ? " DIU" : "",
+			  (did_register & DID_REG_VIU) ? " VIU" : "",
+			  (did_register & DID_REG_FEC) ? " FEC" : "",
+			  (did_register & DID_REG_USB) ? " USB" : "",
+			  (did_register & DID_REG_PATA) ? " PATA" : "");
+	} else {
+		pr_debug("device tree has clock specs, no fallbacks added\n");
+	}
+}
+
+int __init mpc5121_clk_init(void)
+{
+	struct device_node *clk_np;
+	int busfreq;
+
+	/* map the clock control registers */
+	clk_np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
+	if (!clk_np)
+		return -ENODEV;
+	clkregs = of_iomap(clk_np, 0);
+	WARN_ON(!clkregs);
+
+	/* determine the SoC variant we run on */
+	mpc512x_clk_determine_soc();
+
+	/* invalidate all not yet registered clock slots */
+	mpc512x_clk_preset_data();
+
+	/*
+	 * have the device tree scanned for "fixed-clock" nodes (which
+	 * includes the oscillator node if the board's DT provides one)
+	 */
+	of_clk_init(NULL);
+
+	/*
+	 * add a dummy clock for those situations where a clock spec is
+	 * required yet no real clock is involved
+	 */
+	clks[MPC512x_CLK_DUMMY] = mpc512x_clk_fixed("dummy", 0);
+
+	/*
+	 * have all the real nodes in the clock tree populated from REF
+	 * down to all leaves, either starting from the OSC node or from
+	 * a REF root that was created from the IPS bus clock input
+	 */
+	busfreq = get_freq_from_dt("bus-frequency");
+	mpc512x_clk_setup_clock_tree(clk_np, busfreq);
+
+	/* register as an OF clock provider */
+	mpc5121_clk_register_of_provider(clk_np);
+
+	/*
+	 * unbreak not yet adjusted peripheral drivers during migration
+	 * towards fully operational common clock support, and allow
+	 * operation in the absence of clock related device tree specs
+	 */
+	mpc5121_clk_provide_migration_support();
+	mpc5121_clk_provide_backwards_compat();
+
+	return 0;
+}
diff --git a/arch/powerpc/platforms/512x/clock.c b/arch/powerpc/platforms/512x/clock.c
deleted file mode 100644
index fd8a3765341..00000000000
--- a/arch/powerpc/platforms/512x/clock.c
+++ /dev/null
@@ -1,754 +0,0 @@
-/*
- * Copyright (C) 2007,2008 Freescale Semiconductor, Inc. All rights reserved.
- *
- * Author: John Rigby <jrigby@freescale.com>
- *
- * Implements the clk api defined in include/linux/clk.h
- *
- *    Original based on linux/arch/arm/mach-integrator/clock.c
- *
- *    Copyright (C) 2004 ARM Limited.
- *    Written by Deep Blue Solutions Limited.
- *
- * 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.
- */
-#include <linux/kernel.h>
-#include <linux/list.h>
-#include <linux/errno.h>
-#include <linux/err.h>
-#include <linux/module.h>
-#include <linux/string.h>
-#include <linux/clk.h>
-#include <linux/mutex.h>
-#include <linux/io.h>
-
-#include <linux/of_address.h>
-#include <linux/of_platform.h>
-#include <asm/mpc5xxx.h>
-#include <asm/mpc5121.h>
-#include <asm/clk_interface.h>
-
-#include "mpc512x.h"
-
-#undef CLK_DEBUG
-
-static int clocks_initialized;
-
-#define CLK_HAS_RATE	0x1	/* has rate in MHz */
-#define CLK_HAS_CTRL	0x2	/* has control reg and bit */
-
-struct clk {
-	struct list_head node;
-	char name[32];
-	int flags;
-	struct device *dev;
-	unsigned long rate;
-	struct module *owner;
-	void (*calc) (struct clk *);
-	struct clk *parent;
-	int reg, bit;		/* CLK_HAS_CTRL */
-	int div_shift;		/* only used by generic_div_clk_calc */
-};
-
-static LIST_HEAD(clocks);
-static DEFINE_MUTEX(clocks_mutex);
-
-static struct clk *mpc5121_clk_get(struct device *dev, const char *id)
-{
-	struct clk *p, *clk = ERR_PTR(-ENOENT);
-	int dev_match;
-	int id_match;
-
-	if (dev == NULL || id == NULL)
-		return clk;
-
-	mutex_lock(&clocks_mutex);
-	list_for_each_entry(p, &clocks, node) {
-		dev_match = id_match = 0;
-
-		if (dev == p->dev)
-			dev_match++;
-		if (strcmp(id, p->name) == 0)
-			id_match++;
-		if ((dev_match || id_match) && try_module_get(p->owner)) {
-			clk = p;
-			break;
-		}
-	}
-	mutex_unlock(&clocks_mutex);
-
-	return clk;
-}
-
-#ifdef CLK_DEBUG
-static void dump_clocks(void)
-{
-	struct clk *p;
-
-	mutex_lock(&clocks_mutex);
-	printk(KERN_INFO "CLOCKS:\n");
-	list_for_each_entry(p, &clocks, node) {
-		pr_info("  %s=%ld", p->name, p->rate);
-		if (p->parent)
-			pr_cont(" %s=%ld", p->parent->name,
-			       p->parent->rate);
-		if (p->flags & CLK_HAS_CTRL)
-			pr_cont(" reg/bit=%d/%d", p->reg, p->bit);
-		pr_cont("\n");
-	}
-	mutex_unlock(&clocks_mutex);
-}
-#define	DEBUG_CLK_DUMP() dump_clocks()
-#else
-#define	DEBUG_CLK_DUMP()
-#endif
-
-
-static void mpc5121_clk_put(struct clk *clk)
-{
-	module_put(clk->owner);
-}
-
-#define NRPSC 12
-
-struct mpc512x_clockctl {
-	u32 spmr;		/* System PLL Mode Reg */
-	u32 sccr[2];		/* System Clk Ctrl Reg 1 & 2 */
-	u32 scfr1;		/* System Clk Freq Reg 1 */
-	u32 scfr2;		/* System Clk Freq Reg 2 */
-	u32 reserved;
-	u32 bcr;		/* Bread Crumb Reg */
-	u32 pccr[NRPSC];	/* PSC Clk Ctrl Reg 0-11 */
-	u32 spccr;		/* SPDIF Clk Ctrl Reg */
-	u32 cccr;		/* CFM Clk Ctrl Reg */
-	u32 dccr;		/* DIU Clk Cnfg Reg */
-};
-
-static struct mpc512x_clockctl __iomem *clockctl;
-
-static int mpc5121_clk_enable(struct clk *clk)
-{
-	unsigned int mask;
-
-	if (clk->flags & CLK_HAS_CTRL) {
-		mask = in_be32(&clockctl->sccr[clk->reg]);
-		mask |= 1 << clk->bit;
-		out_be32(&clockctl->sccr[clk->reg], mask);
-	}
-	return 0;
-}
-
-static void mpc5121_clk_disable(struct clk *clk)
-{
-	unsigned int mask;
-
-	if (clk->flags & CLK_HAS_CTRL) {
-		mask = in_be32(&clockctl->sccr[clk->reg]);
-		mask &= ~(1 << clk->bit);
-		out_be32(&clockctl->sccr[clk->reg], mask);
-	}
-}
-
-static unsigned long mpc5121_clk_get_rate(struct clk *clk)
-{
-	if (clk->flags & CLK_HAS_RATE)
-		return clk->rate;
-	else
-		return 0;
-}
-
-static long mpc5121_clk_round_rate(struct clk *clk, unsigned long rate)
-{
-	return rate;
-}
-
-static int mpc5121_clk_set_rate(struct clk *clk, unsigned long rate)
-{
-	return 0;
-}
-
-static int clk_register(struct clk *clk)
-{
-	mutex_lock(&clocks_mutex);
-	list_add(&clk->node, &clocks);
-	mutex_unlock(&clocks_mutex);
-	return 0;
-}
-
-static unsigned long spmf_mult(void)
-{
-	/*
-	 * Convert spmf to multiplier
-	 */
-	static int spmf_to_mult[] = {
-		68, 1, 12, 16,
-		20, 24, 28, 32,
-		36, 40, 44, 48,
-		52, 56, 60, 64
-	};
-	int spmf = (in_be32(&clockctl->spmr) >> 24) & 0xf;
-	return spmf_to_mult[spmf];
-}
-
-static unsigned long sysdiv_div_x_2(void)
-{
-	/*
-	 * Convert sysdiv to divisor x 2
-	 * Some divisors have fractional parts so
-	 * multiply by 2 then divide by this value
-	 */
-	static int sysdiv_to_div_x_2[] = {
-		4, 5, 6, 7,
-		8, 9, 10, 14,
-		12, 16, 18, 22,
-		20, 24, 26, 30,
-		28, 32, 34, 38,
-		36, 40, 42, 46,
-		44, 48, 50, 54,
-		52, 56, 58, 62,
-		60, 64, 66,
-	};
-	int sysdiv = (in_be32(&clockctl->scfr2) >> 26) & 0x3f;
-	return sysdiv_to_div_x_2[sysdiv];
-}
-
-static unsigned long ref_to_sys(unsigned long rate)
-{
-	rate *= spmf_mult();
-	rate *= 2;
-	rate /= sysdiv_div_x_2();
-
-	return rate;
-}
-
-static unsigned long sys_to_ref(unsigned long rate)
-{
-	rate *= sysdiv_div_x_2();
-	rate /= 2;
-	rate /= spmf_mult();
-
-	return rate;
-}
-
-static long ips_to_ref(unsigned long rate)
-{
-	int ips_div = (in_be32(&clockctl->scfr1) >> 23) & 0x7;
-
-	rate *= ips_div;	/* csb_clk = ips_clk * ips_div */
-	rate *= 2;		/* sys_clk = csb_clk * 2 */
-	return sys_to_ref(rate);
-}
-
-static unsigned long devtree_getfreq(char *clockname)
-{
-	struct device_node *np;
-	const unsigned int *prop;
-	unsigned int val = 0;
-
-	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-immr");
-	if (np) {
-		prop = of_get_property(np, clockname, NULL);
-		if (prop)
-			val = *prop;
-	    of_node_put(np);
-	}
-	return val;
-}
-
-static void ref_clk_calc(struct clk *clk)
-{
-	unsigned long rate;
-
-	rate = devtree_getfreq("bus-frequency");
-	if (rate == 0) {
-		printk(KERN_ERR "No bus-frequency in dev tree\n");
-		clk->rate = 0;
-		return;
-	}
-	clk->rate = ips_to_ref(rate);
-}
-
-static struct clk ref_clk = {
-	.name = "ref_clk",
-	.calc = ref_clk_calc,
-};
-
-
-static void sys_clk_calc(struct clk *clk)
-{
-	clk->rate = ref_to_sys(ref_clk.rate);
-}
-
-static struct clk sys_clk = {
-	.name = "sys_clk",
-	.calc = sys_clk_calc,
-};
-
-static void diu_clk_calc(struct clk *clk)
-{
-	int diudiv_x_2 = in_be32(&clockctl->scfr1) & 0xff;
-	unsigned long rate;
-
-	rate = sys_clk.rate;
-
-	rate *= 2;
-	rate /= diudiv_x_2;
-
-	clk->rate = rate;
-}
-
-static void viu_clk_calc(struct clk *clk)
-{
-	unsigned long rate;
-
-	rate = sys_clk.rate;
-	rate /= 2;
-	clk->rate = rate;
-}
-
-static void half_clk_calc(struct clk *clk)
-{
-	clk->rate = clk->parent->rate / 2;
-}
-
-static void generic_div_clk_calc(struct clk *clk)
-{
-	int div = (in_be32(&clockctl->scfr1) >> clk->div_shift) & 0x7;
-
-	clk->rate = clk->parent->rate / div;
-}
-
-static void unity_clk_calc(struct clk *clk)
-{
-	clk->rate = clk->parent->rate;
-}
-
-static struct clk csb_clk = {
-	.name = "csb_clk",
-	.calc = half_clk_calc,
-	.parent = &sys_clk,
-};
-
-static void e300_clk_calc(struct clk *clk)
-{
-	int spmf = (in_be32(&clockctl->spmr) >> 16) & 0xf;
-	int ratex2 = clk->parent->rate * spmf;
-
-	clk->rate = ratex2 / 2;
-}
-
-static struct clk e300_clk = {
-	.name = "e300_clk",
-	.calc = e300_clk_calc,
-	.parent = &csb_clk,
-};
-
-static struct clk ips_clk = {
-	.name = "ips_clk",
-	.calc = generic_div_clk_calc,
-	.parent = &csb_clk,
-	.div_shift = 23,
-};
-
-/*
- * Clocks controlled by SCCR1 (.reg = 0)
- */
-static struct clk lpc_clk = {
-	.name = "lpc_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 0,
-	.bit = 30,
-	.calc = generic_div_clk_calc,
-	.parent = &ips_clk,
-	.div_shift = 11,
-};
-
-static struct clk nfc_clk = {
-	.name = "nfc_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 0,
-	.bit = 29,
-	.calc = generic_div_clk_calc,
-	.parent = &ips_clk,
-	.div_shift = 8,
-};
-
-static struct clk pata_clk = {
-	.name = "pata_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 0,
-	.bit = 28,
-	.calc = unity_clk_calc,
-	.parent = &ips_clk,
-};
-
-/*
- * PSC clocks (bits 27 - 16)
- * are setup elsewhere
- */
-
-static struct clk sata_clk = {
-	.name = "sata_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 0,
-	.bit = 14,
-	.calc = unity_clk_calc,
-	.parent = &ips_clk,
-};
-
-static struct clk fec_clk = {
-	.name = "fec_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 0,
-	.bit = 13,
-	.calc = unity_clk_calc,
-	.parent = &ips_clk,
-};
-
-static struct clk pci_clk = {
-	.name = "pci_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 0,
-	.bit = 11,
-	.calc = generic_div_clk_calc,
-	.parent = &csb_clk,
-	.div_shift = 20,
-};
-
-/*
- * Clocks controlled by SCCR2 (.reg = 1)
- */
-static struct clk diu_clk = {
-	.name = "diu_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 31,
-	.calc = diu_clk_calc,
-};
-
-static struct clk viu_clk = {
-	.name = "viu_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 18,
-	.calc = viu_clk_calc,
-};
-
-static struct clk axe_clk = {
-	.name = "axe_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 30,
-	.calc = unity_clk_calc,
-	.parent = &csb_clk,
-};
-
-static struct clk usb1_clk = {
-	.name = "usb1_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 28,
-	.calc = unity_clk_calc,
-	.parent = &csb_clk,
-};
-
-static struct clk usb2_clk = {
-	.name = "usb2_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 27,
-	.calc = unity_clk_calc,
-	.parent = &csb_clk,
-};
-
-static struct clk i2c_clk = {
-	.name = "i2c_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 26,
-	.calc = unity_clk_calc,
-	.parent = &ips_clk,
-};
-
-static struct clk mscan_clk = {
-	.name = "mscan_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 25,
-	.calc = unity_clk_calc,
-	.parent = &ips_clk,
-};
-
-static struct clk sdhc_clk = {
-	.name = "sdhc_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 24,
-	.calc = unity_clk_calc,
-	.parent = &ips_clk,
-};
-
-static struct clk mbx_bus_clk = {
-	.name = "mbx_bus_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 22,
-	.calc = half_clk_calc,
-	.parent = &csb_clk,
-};
-
-static struct clk mbx_clk = {
-	.name = "mbx_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 21,
-	.calc = unity_clk_calc,
-	.parent = &csb_clk,
-};
-
-static struct clk mbx_3d_clk = {
-	.name = "mbx_3d_clk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 20,
-	.calc = generic_div_clk_calc,
-	.parent = &mbx_bus_clk,
-	.div_shift = 14,
-};
-
-static void psc_mclk_in_calc(struct clk *clk)
-{
-	clk->rate = devtree_getfreq("psc_mclk_in");
-	if (!clk->rate)
-		clk->rate = 25000000;
-}
-
-static struct clk psc_mclk_in = {
-	.name = "psc_mclk_in",
-	.calc = psc_mclk_in_calc,
-};
-
-static struct clk spdif_txclk = {
-	.name = "spdif_txclk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 23,
-};
-
-static struct clk spdif_rxclk = {
-	.name = "spdif_rxclk",
-	.flags = CLK_HAS_CTRL,
-	.reg = 1,
-	.bit = 23,
-};
-
-static void ac97_clk_calc(struct clk *clk)
-{
-	/* ac97 bit clock is always 24.567 MHz */
-	clk->rate = 24567000;
-}
-
-static struct clk ac97_clk = {
-	.name = "ac97_clk_in",
-	.calc = ac97_clk_calc,
-};
-
-static struct clk *rate_clks[] = {
-	&ref_clk,
-	&sys_clk,
-	&diu_clk,
-	&viu_clk,
-	&csb_clk,
-	&e300_clk,
-	&ips_clk,
-	&fec_clk,
-	&sata_clk,
-	&pata_clk,
-	&nfc_clk,
-	&lpc_clk,
-	&mbx_bus_clk,
-	&mbx_clk,
-	&mbx_3d_clk,
-	&axe_clk,
-	&usb1_clk,
-	&usb2_clk,
-	&i2c_clk,
-	&mscan_clk,
-	&sdhc_clk,
-	&pci_clk,
-	&psc_mclk_in,
-	&spdif_txclk,
-	&spdif_rxclk,
-	&ac97_clk,
-	NULL
-};
-
-static void rate_clk_init(struct clk *clk)
-{
-	if (clk->calc) {
-		clk->calc(clk);
-		clk->flags |= CLK_HAS_RATE;
-		clk_register(clk);
-	} else {
-		printk(KERN_WARNING
-		       "Could not initialize clk %s without a calc routine\n",
-		       clk->name);
-	}
-}
-
-static void rate_clks_init(void)
-{
-	struct clk **cpp, *clk;
-
-	cpp = rate_clks;
-	while ((clk = *cpp++))
-		rate_clk_init(clk);
-}
-
-/*
- * There are two clk enable registers with 32 enable bits each
- * psc clocks and device clocks are all stored in dev_clks
- */
-static struct clk dev_clks[2][32];
-
-/*
- * Given a psc number return the dev_clk
- * associated with it
- */
-static struct clk *psc_dev_clk(int pscnum)
-{
-	int reg, bit;
-	struct clk *clk;
-
-	reg = 0;
-	bit = 27 - pscnum;
-
-	clk = &dev_clks[reg][bit];
-	clk->reg = 0;
-	clk->bit = bit;
-	return clk;
-}
-
-/*
- * PSC clock rate calculation
- */
-static void psc_calc_rate(struct clk *clk, int pscnum, struct device_node *np)
-{
-	unsigned long mclk_src = sys_clk.rate;
-	unsigned long mclk_div;
-
-	/*
-	 * Can only change value of mclk divider
-	 * when the divider is disabled.
-	 *
-	 * Zero is not a valid divider so minimum
-	 * divider is 1
-	 *
-	 * disable/set divider/enable
-	 */
-	out_be32(&clockctl->pccr[pscnum], 0);
-	out_be32(&clockctl->pccr[pscnum], 0x00020000);
-	out_be32(&clockctl->pccr[pscnum], 0x00030000);
-
-	if (in_be32(&clockctl->pccr[pscnum]) & 0x80) {
-		clk->rate = spdif_rxclk.rate;
-		return;
-	}
-
-	switch ((in_be32(&clockctl->pccr[pscnum]) >> 14) & 0x3) {
-	case 0:
-		mclk_src = sys_clk.rate;
-		break;
-	case 1:
-		mclk_src = ref_clk.rate;
-		break;
-	case 2:
-		mclk_src = psc_mclk_in.rate;
-		break;
-	case 3:
-		mclk_src = spdif_txclk.rate;
-		break;
-	}
-
-	mclk_div = ((in_be32(&clockctl->pccr[pscnum]) >> 17) & 0x7fff) + 1;
-	clk->rate = mclk_src / mclk_div;
-}
-
-/*
- * Find all psc nodes in device tree and assign a clock
- * with name "psc%d_mclk" and dev pointing at the device
- * returned from of_find_device_by_node
- */
-static void psc_clks_init(void)
-{
-	struct device_node *np;
-	struct platform_device *ofdev;
-	u32 reg;
-	const char *psc_compat;
-
-	psc_compat = mpc512x_select_psc_compat();
-	if (!psc_compat)
-		return;
-
-	for_each_compatible_node(np, NULL, psc_compat) {
-		if (!of_property_read_u32(np, "reg", &reg)) {
-			int pscnum = (reg & 0xf00) >> 8;
-			struct clk *clk = psc_dev_clk(pscnum);
-
-			clk->flags = CLK_HAS_RATE | CLK_HAS_CTRL;
-			ofdev = of_find_device_by_node(np);
-			clk->dev = &ofdev->dev;
-			/*
-			 * AC97 is special rate clock does
-			 * not go through normal path
-			 */
-			if (of_device_is_compatible(np, "fsl,mpc5121-psc-ac97"))
-				clk->rate = ac97_clk.rate;
-			else
-				psc_calc_rate(clk, pscnum, np);
-			sprintf(clk->name, "psc%d_mclk", pscnum);
-			clk_register(clk);
-			clk_enable(clk);
-		}
-	}
-}
-
-static struct clk_interface mpc5121_clk_functions = {
-	.clk_get		= mpc5121_clk_get,
-	.clk_enable		= mpc5121_clk_enable,
-	.clk_disable		= mpc5121_clk_disable,
-	.clk_get_rate		= mpc5121_clk_get_rate,
-	.clk_put		= mpc5121_clk_put,
-	.clk_round_rate		= mpc5121_clk_round_rate,
-	.clk_set_rate		= mpc5121_clk_set_rate,
-	.clk_set_parent		= NULL,
-	.clk_get_parent		= NULL,
-};
-
-int __init mpc5121_clk_init(void)
-{
-	struct device_node *np;
-
-	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
-	if (np) {
-		clockctl = of_iomap(np, 0);
-		of_node_put(np);
-	}
-
-	if (!clockctl) {
-		printk(KERN_ERR "Could not map clock control registers\n");
-		return 0;
-	}
-
-	rate_clks_init();
-	psc_clks_init();
-
-	/* leave clockctl mapped forever */
-	/*iounmap(clockctl); */
-	DEBUG_CLK_DUMP();
-	clocks_initialized++;
-	clk_functions = mpc5121_clk_functions;
-	return 0;
-}
diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
index 36b5652aada..adb95f03d4d 100644
--- a/arch/powerpc/platforms/512x/mpc512x_shared.c
+++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
@@ -12,6 +12,7 @@
  * (at your option) any later version.
  */
 
+#include <linux/clk.h>
 #include <linux/kernel.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -68,98 +69,112 @@ struct fsl_diu_shared_fb {
 	bool		in_use;
 };
 
-#define DIU_DIV_MASK	0x000000ff
+/* receives a pixel clock spec in pico seconds, adjusts the DIU clock rate */
 static void mpc512x_set_pixel_clock(unsigned int pixclock)
 {
-	unsigned long bestval, bestfreq, speed, busfreq;
-	unsigned long minpixclock, maxpixclock, pixval;
-	struct mpc512x_ccm __iomem *ccm;
 	struct device_node *np;
-	u32 temp;
-	long err;
-	int i;
+	struct clk *clk_diu;
+	unsigned long epsilon, minpixclock, maxpixclock;
+	unsigned long offset, want, got, delta;
 
-	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
+	/* lookup and enable the DIU clock */
+	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-diu");
 	if (!np) {
-		pr_err("Can't find clock control module.\n");
+		pr_err("Could not find DIU device tree node.\n");
 		return;
 	}
-
-	ccm = of_iomap(np, 0);
+	clk_diu = of_clk_get(np, 0);
+	if (IS_ERR(clk_diu)) {
+		/* backwards compat with device trees that lack clock specs */
+		clk_diu = clk_get_sys(np->name, "ipg");
+	}
 	of_node_put(np);
-	if (!ccm) {
-		pr_err("Can't map clock control module reg.\n");
+	if (IS_ERR(clk_diu)) {
+		pr_err("Could not lookup DIU clock.\n");
 		return;
 	}
-
-	np = of_find_node_by_type(NULL, "cpu");
-	if (np) {
-		const unsigned int *prop =
-			of_get_property(np, "bus-frequency", NULL);
-
-		of_node_put(np);
-		if (prop) {
-			busfreq = *prop;
-		} else {
-			pr_err("Can't get bus-frequency property\n");
-			return;
-		}
-	} else {
-		pr_err("Can't find 'cpu' node.\n");
+	if (clk_prepare_enable(clk_diu)) {
+		pr_err("Could not enable DIU clock.\n");
 		return;
 	}
 
-	/* Pixel Clock configuration */
-	pr_debug("DIU: Bus Frequency = %lu\n", busfreq);
-	speed = busfreq * 4; /* DIU_DIV ratio is 4 * CSB_CLK / DIU_CLK */
-
-	/* Calculate the pixel clock with the smallest error */
-	/* calculate the following in steps to avoid overflow */
-	pr_debug("DIU pixclock in ps - %d\n", pixclock);
-	temp = (1000000000 / pixclock) * 1000;
-	pixclock = temp;
-	pr_debug("DIU pixclock freq - %u\n", pixclock);
-
-	temp = temp / 20; /* pixclock * 0.05 */
-	pr_debug("deviation = %d\n", temp);
-	minpixclock = pixclock - temp;
-	maxpixclock = pixclock + temp;
-	pr_debug("DIU minpixclock - %lu\n", minpixclock);
-	pr_debug("DIU maxpixclock - %lu\n", maxpixclock);
-	pixval = speed/pixclock;
-	pr_debug("DIU pixval = %lu\n", pixval);
-
-	err = LONG_MAX;
-	bestval = pixval;
-	pr_debug("DIU bestval = %lu\n", bestval);
-
-	bestfreq = 0;
-	for (i = -1; i <= 1; i++) {
-		temp = speed / (pixval+i);
-		pr_debug("DIU test pixval i=%d, pixval=%lu, temp freq. = %u\n",
-			i, pixval, temp);
-		if ((temp < minpixclock) || (temp > maxpixclock))
-			pr_debug("DIU exceeds monitor range (%lu to %lu)\n",
-				minpixclock, maxpixclock);
-		else if (abs(temp - pixclock) < err) {
-			pr_debug("Entered the else if block %d\n", i);
-			err = abs(temp - pixclock);
-			bestval = pixval + i;
-			bestfreq = temp;
-		}
+	/*
+	 * convert the picoseconds spec into the desired clock rate,
+	 * determine the acceptable clock range for the monitor (+/- 5%),
+	 * do the calculation in steps to avoid integer overflow
+	 */
+	pr_debug("DIU pixclock in ps - %u\n", pixclock);
+	pixclock = (1000000000 / pixclock) * 1000;
+	pr_debug("DIU pixclock freq  - %u\n", pixclock);
+	epsilon = pixclock / 20; /* pixclock * 0.05 */
+	pr_debug("DIU deviation      - %lu\n", epsilon);
+	minpixclock = pixclock - epsilon;
+	maxpixclock = pixclock + epsilon;
+	pr_debug("DIU minpixclock    - %lu\n", minpixclock);
+	pr_debug("DIU maxpixclock    - %lu\n", maxpixclock);
+
+	/*
+	 * check whether the DIU supports the desired pixel clock
+	 *
+	 * - simply request the desired clock and see what the
+	 *   platform's clock driver will make of it, assuming that it
+	 *   will setup the best approximation of the requested value
+	 * - try other candidate frequencies in the order of decreasing
+	 *   preference (i.e. with increasing distance from the desired
+	 *   pixel clock, and checking the lower frequency before the
+	 *   higher frequency to not overload the hardware) until the
+	 *   first match is found -- any potential subsequent match
+	 *   would only be as good as the former match or typically
+	 *   would be less preferrable
+	 *
+	 * the offset increment of pixelclock divided by 64 is an
+	 * arbitrary choice -- it's simple to calculate, in the typical
+	 * case we expect the first check to succeed already, in the
+	 * worst case seven frequencies get tested (the exact center and
+	 * three more values each to the left and to the right) before
+	 * the 5% tolerance window is exceeded, resulting in fast enough
+	 * execution yet high enough probability of finding a suitable
+	 * value, while the error rate will be in the order of single
+	 * percents
+	 */
+	for (offset = 0; offset <= epsilon; offset += pixclock / 64) {
+		want = pixclock - offset;
+		pr_debug("DIU checking clock - %lu\n", want);
+		clk_set_rate(clk_diu, want);
+		got = clk_get_rate(clk_diu);
+		delta = abs(pixclock - got);
+		if (delta < epsilon)
+			break;
+		if (!offset)
+			continue;
+		want = pixclock + offset;
+		pr_debug("DIU checking clock - %lu\n", want);
+		clk_set_rate(clk_diu, want);
+		got = clk_get_rate(clk_diu);
+		delta = abs(pixclock - got);
+		if (delta < epsilon)
+			break;
 	}
+	if (offset <= epsilon) {
+		pr_debug("DIU clock accepted - %lu\n", want);
+		pr_debug("DIU pixclock want %u, got %lu, delta %lu, eps %lu\n",
+			 pixclock, got, delta, epsilon);
+		return;
+	}
+	pr_warn("DIU pixclock auto search unsuccessful\n");
 
-	pr_debug("DIU chose = %lx\n", bestval);
-	pr_debug("DIU error = %ld\n NomPixClk ", err);
-	pr_debug("DIU: Best Freq = %lx\n", bestfreq);
-	/* Modify DIU_DIV in CCM SCFR1 */
-	temp = in_be32(&ccm->scfr1);
-	pr_debug("DIU: Current value of SCFR1: 0x%08x\n", temp);
-	temp &= ~DIU_DIV_MASK;
-	temp |= (bestval & DIU_DIV_MASK);
-	out_be32(&ccm->scfr1, temp);
-	pr_debug("DIU: Modified value of SCFR1: 0x%08x\n", temp);
-	iounmap(ccm);
+	/*
+	 * what is the most appropriate action to take when the search
+	 * for an available pixel clock which is acceptable to the
+	 * monitor has failed?  disable the DIU (clock) or just provide
+	 * a "best effort"?  we go with the latter
+	 */
+	pr_warn("DIU pixclock best effort fallback (backend's choice)\n");
+	clk_set_rate(clk_diu, pixclock);
+	got = clk_get_rate(clk_diu);
+	delta = abs(pixclock - got);
+	pr_debug("DIU pixclock want %u, got %lu, delta %lu, eps %lu\n",
+		 pixclock, got, delta, epsilon);
 }
 
 static enum fsl_diu_monitor_port
diff --git a/arch/powerpc/platforms/52xx/Kconfig b/arch/powerpc/platforms/52xx/Kconfig
index af54174801f..b625a2c6f4f 100644
--- a/arch/powerpc/platforms/52xx/Kconfig
+++ b/arch/powerpc/platforms/52xx/Kconfig
@@ -1,7 +1,7 @@
 config PPC_MPC52xx
 	bool "52xx-based boards"
 	depends on 6xx
-	select PPC_CLOCK
+	select COMMON_CLK
 	select PPC_PCI_CHOICE
 
 config PPC_MPC5200_SIMPLE