/*
 * Driver for IDT Versaclock 5
 *
 * Copyright (C) 2017 Marek Vasut <marek.vasut@gmail.com>
 *
 * This program 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

/*
 * Possible optimizations:
 * - Use spread spectrum
 * - Use integer divider in FOD if applicable
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/rational.h>
#include <linux/regmap.h>
#include <linux/slab.h>

/* VersaClock5 registers */
#define VC5_OTP_CONTROL                         0x00

/* Factory-reserved register block */
#define VC5_RSVD_DEVICE_ID                      0x01
#define VC5_RSVD_ADC_GAIN_7_0                   0x02
#define VC5_RSVD_ADC_GAIN_15_8                  0x03
#define VC5_RSVD_ADC_OFFSET_7_0                 0x04
#define VC5_RSVD_ADC_OFFSET_15_8                0x05
#define VC5_RSVD_TEMPY                          0x06
#define VC5_RSVD_OFFSET_TBIN                    0x07
#define VC5_RSVD_GAIN                           0x08
#define VC5_RSVD_TEST_NP                        0x09
#define VC5_RSVD_UNUSED                         0x0a
#define VC5_RSVD_BANDGAP_TRIM_UP                0x0b
#define VC5_RSVD_BANDGAP_TRIM_DN                0x0c
#define VC5_RSVD_CLK_R_12_CLK_AMP_4             0x0d
#define VC5_RSVD_CLK_R_34_CLK_AMP_4             0x0e
#define VC5_RSVD_CLK_AMP_123                    0x0f

/* Configuration register block */
#define VC5_PRIM_SRC_SHDN                       0x10
#define VC5_PRIM_SRC_SHDN_EN_XTAL               BIT(7)
#define VC5_PRIM_SRC_SHDN_EN_CLKIN              BIT(6)
#define VC5_PRIM_SRC_SHDN_EN_DOUBLE_XTAL_FREQ   BIT(3)
#define VC5_PRIM_SRC_SHDN_SP                    BIT(1)
#define VC5_PRIM_SRC_SHDN_EN_GBL_SHDN           BIT(0)

#define VC5_VCO_BAND                            0x11
#define VC5_XTAL_X1_LOAD_CAP                    0x12
#define VC5_XTAL_X2_LOAD_CAP                    0x13
#define VC5_REF_DIVIDER                         0x15
#define VC5_REF_DIVIDER_SEL_PREDIV2             BIT(7)
#define VC5_REF_DIVIDER_REF_DIV(n)              ((n) & 0x3f)

#define VC5_VCO_CTRL_AND_PREDIV                 0x16
#define VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV   BIT(7)

#define VC5_FEEDBACK_INT_DIV                    0x17
#define VC5_FEEDBACK_INT_DIV_BITS               0x18
#define VC5_FEEDBACK_FRAC_DIV(n)                (0x19 + (n))
#define VC5_RC_CONTROL0                         0x1e
#define VC5_RC_CONTROL1                         0x1f
/* Register 0x20 is factory reserved */

/* Output divider control for divider 1,2,3,4 */
#define VC5_OUT_DIV_CONTROL(idx)        (0x21 + ((idx) * 0x10))
#define VC5_OUT_DIV_CONTROL_RESET       BIT(7)
#define VC5_OUT_DIV_CONTROL_SELB_NORM   BIT(3)
#define VC5_OUT_DIV_CONTROL_SEL_EXT     BIT(2)
#define VC5_OUT_DIV_CONTROL_INT_MODE    BIT(1)
#define VC5_OUT_DIV_CONTROL_EN_FOD      BIT(0)

#define VC5_OUT_DIV_FRAC(idx, n)        (0x22 + ((idx) * 0x10) + (n))
#define VC5_OUT_DIV_FRAC4_OD_SCEE       BIT(1)

#define VC5_OUT_DIV_STEP_SPREAD(idx, n) (0x26 + ((idx) * 0x10) + (n))
#define VC5_OUT_DIV_SPREAD_MOD(idx, n)  (0x29 + ((idx) * 0x10) + (n))
#define VC5_OUT_DIV_SKEW_INT(idx, n)    (0x2b + ((idx) * 0x10) + (n))
#define VC5_OUT_DIV_INT(idx, n)         (0x2d + ((idx) * 0x10) + (n))
#define VC5_OUT_DIV_SKEW_FRAC(idx)      (0x2f + ((idx) * 0x10))
/* Registers 0x30, 0x40, 0x50 are factory reserved */

/* Clock control register for clock 1,2 */
#define VC5_CLK_OUTPUT_CFG(idx, n)      (0x60 + ((idx) * 0x2) + (n))
#define VC5_CLK_OUTPUT_CFG1_EN_CLKBUF   BIT(0)

#define VC5_CLK_OE_SHDN                         0x68
#define VC5_CLK_OS_SHDN                         0x69

#define VC5_GLOBAL_REGISTER                     0x76
#define VC5_GLOBAL_REGISTER_GLOBAL_RESET        BIT(5)

/* PLL/VCO runs between 2.5 GHz and 3.0 GHz */
#define VC5_PLL_VCO_MIN                         2500000000UL
#define VC5_PLL_VCO_MAX                         3000000000UL

/* VC5 Input mux settings */
#define VC5_MUX_IN_XIN          BIT(0)
#define VC5_MUX_IN_CLKIN        BIT(1)

/* Maximum number of clk_out supported by this driver */
#define VC5_MAX_CLK_OUT_NUM     5

/* Maximum number of FODs supported by this driver */
#define VC5_MAX_FOD_NUM 4

/* flags to describe chip features */
/* chip has built-in oscilator */
#define VC5_HAS_INTERNAL_XTAL   BIT(0)
/* chip has PFD requency doubler */
#define VC5_HAS_PFD_FREQ_DBL    BIT(1)

/* Supported IDT VC5 models. */
enum vc5_model {
        IDT_VC5_5P49V5923,
        IDT_VC5_5P49V5925,
        IDT_VC5_5P49V5933,
        IDT_VC5_5P49V5935,
        IDT_VC6_5P49V6901,
};

/* Structure to describe features of a particular VC5 model */
struct vc5_chip_info {
        const enum vc5_model    model;
        const unsigned int      clk_fod_cnt;
        const unsigned int      clk_out_cnt;
        const u32               flags;
};

struct vc5_driver_data;

struct vc5_hw_data {
        struct clk_hw           hw;
        struct vc5_driver_data  *vc5;
        u32                     div_int;
        u32                     div_frc;
        unsigned int            num;
};

struct vc5_driver_data {
        struct i2c_client       *client;
        struct regmap           *regmap;
        const struct vc5_chip_info      *chip_info;

        struct clk              *pin_xin;
        struct clk              *pin_clkin;
        unsigned char           clk_mux_ins;
        struct clk_hw           clk_mux;
        struct clk_hw           clk_mul;
        struct clk_hw           clk_pfd;
        struct vc5_hw_data      clk_pll;
        struct vc5_hw_data      clk_fod[VC5_MAX_FOD_NUM];
        struct vc5_hw_data      clk_out[VC5_MAX_CLK_OUT_NUM];
};

static const char * const vc5_mux_names[] = {
        "mux"
};

static const char * const vc5_dbl_names[] = {
        "dbl"
};

static const char * const vc5_pfd_names[] = {
        "pfd"
};

static const char * const vc5_pll_names[] = {
        "pll"
};

static const char * const vc5_fod_names[] = {
        "fod0", "fod1", "fod2", "fod3",
};

static const char * const vc5_clk_out_names[] = {
        "out0_sel_i2cb", "out1", "out2", "out3", "out4",
};

/*
 * VersaClock5 i2c regmap
 */
static bool vc5_regmap_is_writeable(struct device *dev, unsigned int reg)
{
        /* Factory reserved regs, make them read-only */
        if (reg <= 0xf)
                return false;

        /* Factory reserved regs, make them read-only */
        if (reg == 0x14 || reg == 0x1c || reg == 0x1d)
                return false;

        return true;
}

static const struct regmap_config vc5_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .cache_type = REGCACHE_RBTREE,
        .max_register = 0x76,
        .writeable_reg = vc5_regmap_is_writeable,
};

/*
 * VersaClock5 input multiplexer between XTAL and CLKIN divider
 */
static unsigned char vc5_mux_get_parent(struct clk_hw *hw)
{
        struct vc5_driver_data *vc5 =
                container_of(hw, struct vc5_driver_data, clk_mux);
        const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL | VC5_PRIM_SRC_SHDN_EN_CLKIN;
        unsigned int src;

        regmap_read(vc5->regmap, VC5_PRIM_SRC_SHDN, &src);
        src &= mask;

        if (src == VC5_PRIM_SRC_SHDN_EN_XTAL)
                return 0;

        if (src == VC5_PRIM_SRC_SHDN_EN_CLKIN)
                return 1;

        dev_warn(&vc5->client->dev,
                 "Invalid clock input configuration (%02x)\n", src);
        return 0;
}

static int vc5_mux_set_parent(struct clk_hw *hw, u8 index)
{
        struct vc5_driver_data *vc5 =
                container_of(hw, struct vc5_driver_data, clk_mux);
        const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL | VC5_PRIM_SRC_SHDN_EN_CLKIN;
        u8 src;

        if ((index > 1) || !vc5->clk_mux_ins)
                return -EINVAL;

        if (vc5->clk_mux_ins == (VC5_MUX_IN_CLKIN | VC5_MUX_IN_XIN)) {
                if (index == 0)
                        src = VC5_PRIM_SRC_SHDN_EN_XTAL;
                if (index == 1)
                        src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
        } else {
                if (index != 0)
                        return -EINVAL;

                if (vc5->clk_mux_ins == VC5_MUX_IN_XIN)
                        src = VC5_PRIM_SRC_SHDN_EN_XTAL;
                if (vc5->clk_mux_ins == VC5_MUX_IN_CLKIN)
                        src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
        }

        return regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN, mask, src);
}

static const struct clk_ops vc5_mux_ops = {
        .set_parent     = vc5_mux_set_parent,
        .get_parent     = vc5_mux_get_parent,
};

static unsigned long vc5_dbl_recalc_rate(struct clk_hw *hw,
                                         unsigned long parent_rate)
{
        struct vc5_driver_data *vc5 =
                container_of(hw, struct vc5_driver_data, clk_mul);
        unsigned int premul;

        regmap_read(vc5->regmap, VC5_PRIM_SRC_SHDN, &premul);
        if (premul & VC5_PRIM_SRC_SHDN_EN_DOUBLE_XTAL_FREQ)
                parent_rate *= 2;

        return parent_rate;
}

static long vc5_dbl_round_rate(struct clk_hw *hw, unsigned long rate,
                               unsigned long *parent_rate)
{
        if ((*parent_rate == rate) || ((*parent_rate * 2) == rate))
                return rate;
        else
                return -EINVAL;
}

static int vc5_dbl_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        struct vc5_driver_data *vc5 =
                container_of(hw, struct vc5_driver_data, clk_mul);
        u32 mask;

        if ((parent_rate * 2) == rate)
                mask = VC5_PRIM_SRC_SHDN_EN_DOUBLE_XTAL_FREQ;
        else
                mask = 0;

        regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN,
                           VC5_PRIM_SRC_SHDN_EN_DOUBLE_XTAL_FREQ,
                           mask);

        return 0;
}

static const struct clk_ops vc5_dbl_ops = {
        .recalc_rate    = vc5_dbl_recalc_rate,
        .round_rate     = vc5_dbl_round_rate,
        .set_rate       = vc5_dbl_set_rate,
};

static unsigned long vc5_pfd_recalc_rate(struct clk_hw *hw,
                                         unsigned long parent_rate)
{
        struct vc5_driver_data *vc5 =
                container_of(hw, struct vc5_driver_data, clk_pfd);
        unsigned int prediv, div;

        regmap_read(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV, &prediv);

        /* The bypass_prediv is set, PLL fed from Ref_in directly. */
        if (prediv & VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV)
                return parent_rate;

        regmap_read(vc5->regmap, VC5_REF_DIVIDER, &div);

        /* The Sel_prediv2 is set, PLL fed from prediv2 (Ref_in / 2) */
        if (div & VC5_REF_DIVIDER_SEL_PREDIV2)
                return parent_rate / 2;
        else
                return parent_rate / VC5_REF_DIVIDER_REF_DIV(div);
}

static long vc5_pfd_round_rate(struct clk_hw *hw, unsigned long rate,
                               unsigned long *parent_rate)
{
        unsigned long idiv;

        /* PLL cannot operate with input clock above 50 MHz. */
        if (rate > 50000000)
                return -EINVAL;

        /* CLKIN within range of PLL input, feed directly to PLL. */
        if (*parent_rate <= 50000000)
                return *parent_rate;

        idiv = DIV_ROUND_UP(*parent_rate, rate);
        if (idiv > 127)
                return -EINVAL;

        return *parent_rate / idiv;
}

static int vc5_pfd_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        struct vc5_driver_data *vc5 =
                container_of(hw, struct vc5_driver_data, clk_pfd);
        unsigned long idiv;
        u8 div;

        /* CLKIN within range of PLL input, feed directly to PLL. */
        if (parent_rate <= 50000000) {
                regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
                                   VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV,
                                   VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV);
                regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, 0x00);
                return 0;
        }

        idiv = DIV_ROUND_UP(parent_rate, rate);

        /* We have dedicated div-2 predivider. */
        if (idiv == 2)
                div = VC5_REF_DIVIDER_SEL_PREDIV2;
        else
                div = VC5_REF_DIVIDER_REF_DIV(idiv);

        regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, div);
        regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
                           VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV, 0);

        return 0;
}

static const struct clk_ops vc5_pfd_ops = {
        .recalc_rate    = vc5_pfd_recalc_rate,
        .round_rate     = vc5_pfd_round_rate,
        .set_rate       = vc5_pfd_set_rate,
};

/*
 * VersaClock5 PLL/VCO
 */
static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
                                         unsigned long parent_rate)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        u32 div_int, div_frc;
        u8 fb[5];

        regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);

        div_int = (fb[0] << 4) | (fb[1] >> 4);
        div_frc = (fb[2] << 16) | (fb[3] << 8) | fb[4];

        /* The PLL divider has 12 integer bits and 24 fractional bits */
        return (parent_rate * div_int) + ((parent_rate * div_frc) >> 24);
}

static long vc5_pll_round_rate(struct clk_hw *hw, unsigned long rate,
                               unsigned long *parent_rate)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        u32 div_int;
        u64 div_frc;

        if (rate < VC5_PLL_VCO_MIN)
                rate = VC5_PLL_VCO_MIN;
        if (rate > VC5_PLL_VCO_MAX)
                rate = VC5_PLL_VCO_MAX;

        /* Determine integer part, which is 12 bit wide */
        div_int = rate / *parent_rate;
        if (div_int > 0xfff)
                rate = *parent_rate * 0xfff;

        /* Determine best fractional part, which is 24 bit wide */
        div_frc = rate % *parent_rate;
        div_frc *= BIT(24) - 1;
        do_div(div_frc, *parent_rate);

        hwdata->div_int = div_int;
        hwdata->div_frc = (u32)div_frc;

        return (*parent_rate * div_int) + ((*parent_rate * div_frc) >> 24);
}

static int vc5_pll_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        u8 fb[5];

        fb[0] = hwdata->div_int >> 4;
        fb[1] = hwdata->div_int << 4;
        fb[2] = hwdata->div_frc >> 16;
        fb[3] = hwdata->div_frc >> 8;
        fb[4] = hwdata->div_frc;

        return regmap_bulk_write(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
}

static const struct clk_ops vc5_pll_ops = {
        .recalc_rate    = vc5_pll_recalc_rate,
        .round_rate     = vc5_pll_round_rate,
        .set_rate       = vc5_pll_set_rate,
};

static unsigned long vc5_fod_recalc_rate(struct clk_hw *hw,
                                         unsigned long parent_rate)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        /* VCO frequency is divided by two before entering FOD */
        u32 f_in = parent_rate / 2;
        u32 div_int, div_frc;
        u8 od_int[2];
        u8 od_frc[4];

        regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
                         od_int, 2);
        regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
                         od_frc, 4);

        div_int = (od_int[0] << 4) | (od_int[1] >> 4);
        div_frc = (od_frc[0] << 22) | (od_frc[1] << 14) |
                  (od_frc[2] << 6) | (od_frc[3] >> 2);

        /* Avoid division by zero if the output is not configured. */
        if (div_int == 0 && div_frc == 0)
                return 0;

        /* The PLL divider has 12 integer bits and 30 fractional bits */
        return div64_u64((u64)f_in << 24ULL, ((u64)div_int << 24ULL) + div_frc);
}

static long vc5_fod_round_rate(struct clk_hw *hw, unsigned long rate,
                               unsigned long *parent_rate)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        /* VCO frequency is divided by two before entering FOD */
        u32 f_in = *parent_rate / 2;
        u32 div_int;
        u64 div_frc;

        /* Determine integer part, which is 12 bit wide */
        div_int = f_in / rate;
        /*
         * WARNING: The clock chip does not output signal if the integer part
         *          of the divider is 0xfff and fractional part is non-zero.
         *          Clamp the divider at 0xffe to keep the code simple.
         */
        if (div_int > 0xffe) {
                div_int = 0xffe;
                rate = f_in / div_int;
        }

        /* Determine best fractional part, which is 30 bit wide */
        div_frc = f_in % rate;
        div_frc <<= 24;
        do_div(div_frc, rate);

        hwdata->div_int = div_int;
        hwdata->div_frc = (u32)div_frc;

        return div64_u64((u64)f_in << 24ULL, ((u64)div_int << 24ULL) + div_frc);
}

static int vc5_fod_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        u8 data[14] = {
                hwdata->div_frc >> 22, hwdata->div_frc >> 14,
                hwdata->div_frc >> 6, hwdata->div_frc << 2,
                0, 0, 0, 0, 0,
                0, 0,
                hwdata->div_int >> 4, hwdata->div_int << 4,
                0
        };

        regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
                          data, 14);

        /*
         * Toggle magic bit in undocumented register for unknown reason.
         * This is what the IDT timing commander tool does and the chip
         * datasheet somewhat implies this is needed, but the register
         * and the bit is not documented.
         */
        regmap_update_bits(vc5->regmap, VC5_GLOBAL_REGISTER,
                           VC5_GLOBAL_REGISTER_GLOBAL_RESET, 0);
        regmap_update_bits(vc5->regmap, VC5_GLOBAL_REGISTER,
                           VC5_GLOBAL_REGISTER_GLOBAL_RESET,
                           VC5_GLOBAL_REGISTER_GLOBAL_RESET);
        return 0;
}

static const struct clk_ops vc5_fod_ops = {
        .recalc_rate    = vc5_fod_recalc_rate,
        .round_rate     = vc5_fod_round_rate,
        .set_rate       = vc5_fod_set_rate,
};

static int vc5_clk_out_prepare(struct clk_hw *hw)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        const u8 mask = VC5_OUT_DIV_CONTROL_SELB_NORM |
                        VC5_OUT_DIV_CONTROL_SEL_EXT |
                        VC5_OUT_DIV_CONTROL_EN_FOD;
        unsigned int src;
        int ret;

        /*
         * If the input mux is disabled, enable it first and
         * select source from matching FOD.
         */
        regmap_read(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num), &src);
        if ((src & mask) == 0) {
                src = VC5_OUT_DIV_CONTROL_RESET | VC5_OUT_DIV_CONTROL_EN_FOD;
                ret = regmap_update_bits(vc5->regmap,
                                         VC5_OUT_DIV_CONTROL(hwdata->num),
                                         mask | VC5_OUT_DIV_CONTROL_RESET, src);
                if (ret)
                        return ret;
        }

        /* Enable the clock buffer */
        regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num, 1),
                           VC5_CLK_OUTPUT_CFG1_EN_CLKBUF,
                           VC5_CLK_OUTPUT_CFG1_EN_CLKBUF);
        return 0;
}

static void vc5_clk_out_unprepare(struct clk_hw *hw)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;

        /* Disable the clock buffer */
        regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num, 1),
                           VC5_CLK_OUTPUT_CFG1_EN_CLKBUF, 0);
}

static unsigned char vc5_clk_out_get_parent(struct clk_hw *hw)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        const u8 mask = VC5_OUT_DIV_CONTROL_SELB_NORM |
                        VC5_OUT_DIV_CONTROL_SEL_EXT |
                        VC5_OUT_DIV_CONTROL_EN_FOD;
        const u8 fodclkmask = VC5_OUT_DIV_CONTROL_SELB_NORM |
                              VC5_OUT_DIV_CONTROL_EN_FOD;
        const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
                          VC5_OUT_DIV_CONTROL_SEL_EXT;
        unsigned int src;

        regmap_read(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num), &src);
        src &= mask;

        if (src == 0)   /* Input mux set to DISABLED */
                return 0;

        if ((src & fodclkmask) == VC5_OUT_DIV_CONTROL_EN_FOD)
                return 0;

        if (src == extclk)
                return 1;

        dev_warn(&vc5->client->dev,
                 "Invalid clock output configuration (%02x)\n", src);
        return 0;
}

static int vc5_clk_out_set_parent(struct clk_hw *hw, u8 index)
{
        struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
        struct vc5_driver_data *vc5 = hwdata->vc5;
        const u8 mask = VC5_OUT_DIV_CONTROL_RESET |
                        VC5_OUT_DIV_CONTROL_SELB_NORM |
                        VC5_OUT_DIV_CONTROL_SEL_EXT |
                        VC5_OUT_DIV_CONTROL_EN_FOD;
        const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
                          VC5_OUT_DIV_CONTROL_SEL_EXT;
        u8 src = VC5_OUT_DIV_CONTROL_RESET;

        if (index == 0)
                src |= VC5_OUT_DIV_CONTROL_EN_FOD;
        else
                src |= extclk;

        return regmap_update_bits(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num),
                                  mask, src);
}

static const struct clk_ops vc5_clk_out_ops = {
        .prepare        = vc5_clk_out_prepare,
        .unprepare      = vc5_clk_out_unprepare,
        .set_parent     = vc5_clk_out_set_parent,
        .get_parent     = vc5_clk_out_get_parent,
};

static struct clk_hw *vc5_of_clk_get(struct of_phandle_args *clkspec,
                                     void *data)
{
        struct vc5_driver_data *vc5 = data;
        unsigned int idx = clkspec->args[0];

        if (idx >= vc5->chip_info->clk_out_cnt)
                return ERR_PTR(-EINVAL);

        return &vc5->clk_out[idx].hw;
}

static int vc5_map_index_to_output(const enum vc5_model model,
                                   const unsigned int n)
{
        switch (model) {
        case IDT_VC5_5P49V5933:
                return (n == 0) ? 0 : 3;
        case IDT_VC5_5P49V5923:
        case IDT_VC5_5P49V5925:
        case IDT_VC5_5P49V5935:
        case IDT_VC6_5P49V6901:
        default:
                return n;
        }
}

static const struct of_device_id clk_vc5_of_match[];

static int vc5_probe(struct i2c_client *client,
                     const struct i2c_device_id *id)
{
        struct vc5_driver_data *vc5;
        struct clk_init_data init;
        const char *parent_names[2];
        unsigned int n, idx = 0;
        int ret;

        vc5 = devm_kzalloc(&client->dev, sizeof(*vc5), GFP_KERNEL);
        if (vc5 == NULL)
                return -ENOMEM;

        i2c_set_clientdata(client, vc5);
        vc5->client = client;
        vc5->chip_info = of_device_get_match_data(&client->dev);

        vc5->pin_xin = devm_clk_get(&client->dev, "xin");
        if (PTR_ERR(vc5->pin_xin) == -EPROBE_DEFER)
                return -EPROBE_DEFER;

        vc5->pin_clkin = devm_clk_get(&client->dev, "clkin");
        if (PTR_ERR(vc5->pin_clkin) == -EPROBE_DEFER)
                return -EPROBE_DEFER;

        vc5->regmap = devm_regmap_init_i2c(client, &vc5_regmap_config);
        if (IS_ERR(vc5->regmap)) {
                dev_err(&client->dev, "failed to allocate register map\n");
                return PTR_ERR(vc5->regmap);
        }

        /* Register clock input mux */
        memset(&init, 0, sizeof(init));

        if (!IS_ERR(vc5->pin_xin)) {
                vc5->clk_mux_ins |= VC5_MUX_IN_XIN;
                parent_names[init.num_parents++] = __clk_get_name(vc5->pin_xin);
        } else if (vc5->chip_info->flags & VC5_HAS_INTERNAL_XTAL) {
                vc5->pin_xin = clk_register_fixed_rate(&client->dev,
                                                       "internal-xtal", NULL,
                                                       0, 25000000);
                if (IS_ERR(vc5->pin_xin))
                        return PTR_ERR(vc5->pin_xin);
                vc5->clk_mux_ins |= VC5_MUX_IN_XIN;
                parent_names[init.num_parents++] = __clk_get_name(vc5->pin_xin);
        }

        if (!IS_ERR(vc5->pin_clkin)) {
                vc5->clk_mux_ins |= VC5_MUX_IN_CLKIN;
                parent_names[init.num_parents++] =
                        __clk_get_name(vc5->pin_clkin);
        }

        if (!init.num_parents) {
                dev_err(&client->dev, "no input clock specified!\n");
                return -EINVAL;
        }

        init.name = vc5_mux_names[0];
        init.ops = &vc5_mux_ops;
        init.flags = 0;
        init.parent_names = parent_names;
        vc5->clk_mux.init = &init;
        ret = devm_clk_hw_register(&client->dev, &vc5->clk_mux);
        if (ret) {
                dev_err(&client->dev, "unable to register %s\n", init.name);
                goto err_clk;
        }

        if (vc5->chip_info->flags & VC5_HAS_PFD_FREQ_DBL) {
                /* Register frequency doubler */
                memset(&init, 0, sizeof(init));
                init.name = vc5_dbl_names[0];
                init.ops = &vc5_dbl_ops;
                init.flags = CLK_SET_RATE_PARENT;
                init.parent_names = vc5_mux_names;
                init.num_parents = 1;
                vc5->clk_mul.init = &init;
                ret = devm_clk_hw_register(&client->dev, &vc5->clk_mul);
                if (ret) {
                        dev_err(&client->dev, "unable to register %s\n",
                                init.name);
                        goto err_clk;
                }
        }

        /* Register PFD */
        memset(&init, 0, sizeof(init));
        init.name = vc5_pfd_names[0];
        init.ops = &vc5_pfd_ops;
        init.flags = CLK_SET_RATE_PARENT;
        if (vc5->chip_info->flags & VC5_HAS_PFD_FREQ_DBL)
                init.parent_names = vc5_dbl_names;
        else
                init.parent_names = vc5_mux_names;
        init.num_parents = 1;
        vc5->clk_pfd.init = &init;
        ret = devm_clk_hw_register(&client->dev, &vc5->clk_pfd);
        if (ret) {
                dev_err(&client->dev, "unable to register %s\n", init.name);
                goto err_clk;
        }

        /* Register PLL */
        memset(&init, 0, sizeof(init));
        init.name = vc5_pll_names[0];
        init.ops = &vc5_pll_ops;
        init.flags = CLK_SET_RATE_PARENT;
        init.parent_names = vc5_pfd_names;
        init.num_parents = 1;
        vc5->clk_pll.num = 0;
        vc5->clk_pll.vc5 = vc5;
        vc5->clk_pll.hw.init = &init;
        ret = devm_clk_hw_register(&client->dev, &vc5->clk_pll.hw);
        if (ret) {
                dev_err(&client->dev, "unable to register %s\n", init.name);
                goto err_clk;
        }

        /* Register FODs */
        for (n = 0; n < vc5->chip_info->clk_fod_cnt; n++) {
                idx = vc5_map_index_to_output(vc5->chip_info->model, n);
                memset(&init, 0, sizeof(init));
                init.name = vc5_fod_names[idx];
                init.ops = &vc5_fod_ops;
                init.flags = CLK_SET_RATE_PARENT;
                init.parent_names = vc5_pll_names;
                init.num_parents = 1;
                vc5->clk_fod[n].num = idx;
                vc5->clk_fod[n].vc5 = vc5;
                vc5->clk_fod[n].hw.init = &init;
                ret = devm_clk_hw_register(&client->dev, &vc5->clk_fod[n].hw);
                if (ret) {
                        dev_err(&client->dev, "unable to register %s\n",
                                init.name);
                        goto err_clk;
                }
        }

        /* Register MUX-connected OUT0_I2C_SELB output */
        memset(&init, 0, sizeof(init));
        init.name = vc5_clk_out_names[0];
        init.ops = &vc5_clk_out_ops;
        init.flags = CLK_SET_RATE_PARENT;
        init.parent_names = vc5_mux_names;
        init.num_parents = 1;
        vc5->clk_out[0].num = idx;
        vc5->clk_out[0].vc5 = vc5;
        vc5->clk_out[0].hw.init = &init;
        ret = devm_clk_hw_register(&client->dev, &vc5->clk_out[0].hw);
        if (ret) {
                dev_err(&client->dev, "unable to register %s\n",
                        init.name);
                goto err_clk;
        }

        /* Register FOD-connected OUTx outputs */
        for (n = 1; n < vc5->chip_info->clk_out_cnt; n++) {
                idx = vc5_map_index_to_output(vc5->chip_info->model, n - 1);
                parent_names[0] = vc5_fod_names[idx];
                if (n == 1)
                        parent_names[1] = vc5_mux_names[0];
                else
                        parent_names[1] = vc5_clk_out_names[n - 1];

                memset(&init, 0, sizeof(init));
                init.name = vc5_clk_out_names[idx + 1];
                init.ops = &vc5_clk_out_ops;
                init.flags = CLK_SET_RATE_PARENT;
                init.parent_names = parent_names;
                init.num_parents = 2;
                vc5->clk_out[n].num = idx;
                vc5->clk_out[n].vc5 = vc5;
                vc5->clk_out[n].hw.init = &init;
                ret = devm_clk_hw_register(&client->dev,
                                           &vc5->clk_out[n].hw);
                if (ret) {
                        dev_err(&client->dev, "unable to register %s\n",
                                init.name);
                        goto err_clk;
                }
        }

        ret = of_clk_add_hw_provider(client->dev.of_node, vc5_of_clk_get, vc5);
        if (ret) {
                dev_err(&client->dev, "unable to add clk provider\n");
                goto err_clk;
        }

        return 0;

err_clk:
        if (vc5->chip_info->flags & VC5_HAS_INTERNAL_XTAL)
                clk_unregister_fixed_rate(vc5->pin_xin);
        return ret;
}

static int vc5_remove(struct i2c_client *client)
{
        struct vc5_driver_data *vc5 = i2c_get_clientdata(client);

        of_clk_del_provider(client->dev.of_node);

        if (vc5->chip_info->flags & VC5_HAS_INTERNAL_XTAL)
                clk_unregister_fixed_rate(vc5->pin_xin);

        return 0;
}

static const struct vc5_chip_info idt_5p49v5923_info = {
        .model = IDT_VC5_5P49V5923,
        .clk_fod_cnt = 2,
        .clk_out_cnt = 3,
        .flags = 0,
};

static const struct vc5_chip_info idt_5p49v5925_info = {
        .model = IDT_VC5_5P49V5925,
        .clk_fod_cnt = 4,
        .clk_out_cnt = 5,
        .flags = 0,
};

static const struct vc5_chip_info idt_5p49v5933_info = {
        .model = IDT_VC5_5P49V5933,
        .clk_fod_cnt = 2,
        .clk_out_cnt = 3,
        .flags = VC5_HAS_INTERNAL_XTAL,
};

static const struct vc5_chip_info idt_5p49v5935_info = {
        .model = IDT_VC5_5P49V5935,
        .clk_fod_cnt = 4,
        .clk_out_cnt = 5,
        .flags = VC5_HAS_INTERNAL_XTAL,
};

static const struct vc5_chip_info idt_5p49v6901_info = {
        .model = IDT_VC6_5P49V6901,
        .clk_fod_cnt = 4,
        .clk_out_cnt = 5,
        .flags = VC5_HAS_PFD_FREQ_DBL,
};

static const struct i2c_device_id vc5_id[] = {
        { "5p49v5923", .driver_data = IDT_VC5_5P49V5923 },
        { "5p49v5925", .driver_data = IDT_VC5_5P49V5925 },
        { "5p49v5933", .driver_data = IDT_VC5_5P49V5933 },
        { "5p49v5935", .driver_data = IDT_VC5_5P49V5935 },
        { "5p49v6901", .driver_data = IDT_VC6_5P49V6901 },
        { }
};
MODULE_DEVICE_TABLE(i2c, vc5_id);

static const struct of_device_id clk_vc5_of_match[] = {
        { .compatible = "idt,5p49v5923", .data = &idt_5p49v5923_info },
        { .compatible = "idt,5p49v5925", .data = &idt_5p49v5925_info },
        { .compatible = "idt,5p49v5933", .data = &idt_5p49v5933_info },
        { .compatible = "idt,5p49v5935", .data = &idt_5p49v5935_info },
        { .compatible = "idt,5p49v6901", .data = &idt_5p49v6901_info },
        { },
};
MODULE_DEVICE_TABLE(of, clk_vc5_of_match);

static struct i2c_driver vc5_driver = {
        .driver = {
                .name = "vc5",
                .of_match_table = clk_vc5_of_match,
        },
        .probe          = vc5_probe,
        .remove         = vc5_remove,
        .id_table       = vc5_id,
};
module_i2c_driver(vc5_driver);

MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
MODULE_DESCRIPTION("IDT VersaClock 5 driver");
MODULE_LICENSE("GPL");