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.
>>

1 files changed, 1221 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/512x/clock-commonclk.c b/arch/powerpc/platforms/512x/clock-commonclk.c
new file mode 100644
index 000000000000..6eb614a271fb
--- /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;
+}