// SPDX-License-Identifier: GPL-2.0+

#define pr_fmt(fmt) "clk-aspeed: " fmt

#include <linux/clk-provider.h>
#include <linux/mfd/syscon.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <dt-bindings/clock/aspeed-clock.h>

#define ASPEED_NUM_CLKS         36

#define ASPEED_RESET2_OFFSET    32

#define ASPEED_RESET_CTRL       0x04
#define ASPEED_CLK_SELECTION    0x08
#define ASPEED_CLK_STOP_CTRL    0x0c
#define ASPEED_MPLL_PARAM       0x20
#define ASPEED_HPLL_PARAM       0x24
#define  AST2500_HPLL_BYPASS_EN BIT(20)
#define  AST2400_HPLL_PROGRAMMED BIT(18)
#define  AST2400_HPLL_BYPASS_EN BIT(17)
#define ASPEED_MISC_CTRL        0x2c
#define  UART_DIV13_EN          BIT(12)
#define ASPEED_STRAP            0x70
#define  CLKIN_25MHZ_EN         BIT(23)
#define  AST2400_CLK_SOURCE_SEL BIT(18)
#define ASPEED_CLK_SELECTION_2  0xd8
#define ASPEED_RESET_CTRL2      0xd4

/* Globally visible clocks */
static DEFINE_SPINLOCK(aspeed_clk_lock);

/* Keeps track of all clocks */
static struct clk_hw_onecell_data *aspeed_clk_data;

static void __iomem *scu_base;

/**
 * struct aspeed_gate_data - Aspeed gated clocks
 * @clock_idx: bit used to gate this clock in the clock register
 * @reset_idx: bit used to reset this IP in the reset register. -1 if no
 *             reset is required when enabling the clock
 * @name: the clock name
 * @parent_name: the name of the parent clock
 * @flags: standard clock framework flags
 */
struct aspeed_gate_data {
        u8              clock_idx;
        s8              reset_idx;
        const char      *name;
        const char      *parent_name;
        unsigned long   flags;
};

/**
 * struct aspeed_clk_gate - Aspeed specific clk_gate structure
 * @hw:         handle between common and hardware-specific interfaces
 * @reg:        register controlling gate
 * @clock_idx:  bit used to gate this clock in the clock register
 * @reset_idx:  bit used to reset this IP in the reset register. -1 if no
 *              reset is required when enabling the clock
 * @flags:      hardware-specific flags
 * @lock:       register lock
 *
 * Some of the clocks in the Aspeed SoC must be put in reset before enabling.
 * This modified version of clk_gate allows an optional reset bit to be
 * specified.
 */
struct aspeed_clk_gate {
        struct clk_hw   hw;
        struct regmap   *map;
        u8              clock_idx;
        s8              reset_idx;
        u8              flags;
        spinlock_t      *lock;
};

#define to_aspeed_clk_gate(_hw) container_of(_hw, struct aspeed_clk_gate, hw)

/* TODO: ask Aspeed about the actual parent data */
static const struct aspeed_gate_data aspeed_gates[] = {
        /*                               clk rst   name                 parent  flags */
        [ASPEED_CLK_GATE_ECLK] =        {  0, -1, "eclk-gate",          "eclk", 0 }, /* Video Engine */
        [ASPEED_CLK_GATE_GCLK] =        {  1,  7, "gclk-gate",          NULL,   0 }, /* 2D engine */
        [ASPEED_CLK_GATE_MCLK] =        {  2, -1, "mclk-gate",          "mpll", CLK_IS_CRITICAL }, /* SDRAM */
        [ASPEED_CLK_GATE_VCLK] =        {  3,  6, "vclk-gate",          NULL,   0 }, /* Video Capture */
        [ASPEED_CLK_GATE_BCLK] =        {  4,  8, "bclk-gate",          "bclk", CLK_IS_CRITICAL }, /* PCIe/PCI */
        [ASPEED_CLK_GATE_DCLK] =        {  5, -1, "dclk-gate",          NULL,   CLK_IS_CRITICAL }, /* DAC */
        [ASPEED_CLK_GATE_REFCLK] =      {  6, -1, "refclk-gate",        "clkin", CLK_IS_CRITICAL },
        [ASPEED_CLK_GATE_USBPORT2CLK] = {  7,  3, "usb-port2-gate",     NULL,   0 }, /* USB2.0 Host port 2 */
        [ASPEED_CLK_GATE_LCLK] =        {  8,  5, "lclk-gate",          NULL,   0 }, /* LPC */
        [ASPEED_CLK_GATE_USBUHCICLK] =  {  9, 15, "usb-uhci-gate",      NULL,   0 }, /* USB1.1 (requires port 2 enabled) */
        [ASPEED_CLK_GATE_D1CLK] =       { 10, 13, "d1clk-gate",         NULL,   0 }, /* GFX CRT */
        [ASPEED_CLK_GATE_YCLK] =        { 13,  4, "yclk-gate",          NULL,   0 }, /* HAC */
        [ASPEED_CLK_GATE_USBPORT1CLK] = { 14, 14, "usb-port1-gate",     NULL,   0 }, /* USB2 hub/USB2 host port 1/USB1.1 dev */
        [ASPEED_CLK_GATE_UART1CLK] =    { 15, -1, "uart1clk-gate",      "uart", 0 }, /* UART1 */
        [ASPEED_CLK_GATE_UART2CLK] =    { 16, -1, "uart2clk-gate",      "uart", 0 }, /* UART2 */
        [ASPEED_CLK_GATE_UART5CLK] =    { 17, -1, "uart5clk-gate",      "uart", 0 }, /* UART5 */
        [ASPEED_CLK_GATE_ESPICLK] =     { 19, -1, "espiclk-gate",       NULL,   0 }, /* eSPI */
        [ASPEED_CLK_GATE_MAC1CLK] =     { 20, 11, "mac1clk-gate",       "mac",  0 }, /* MAC1 */
        [ASPEED_CLK_GATE_MAC2CLK] =     { 21, 12, "mac2clk-gate",       "mac",  0 }, /* MAC2 */
        [ASPEED_CLK_GATE_RSACLK] =      { 24, -1, "rsaclk-gate",        NULL,   0 }, /* RSA */
        [ASPEED_CLK_GATE_UART3CLK] =    { 25, -1, "uart3clk-gate",      "uart", 0 }, /* UART3 */
        [ASPEED_CLK_GATE_UART4CLK] =    { 26, -1, "uart4clk-gate",      "uart", 0 }, /* UART4 */
        [ASPEED_CLK_GATE_SDCLK] =       { 27, 16, "sdclk-gate",         NULL,   0 }, /* SDIO/SD */
        [ASPEED_CLK_GATE_LHCCLK] =      { 28, -1, "lhclk-gate",         "lhclk", 0 }, /* LPC master/LPC+ */
};

static const struct clk_div_table ast2500_mac_div_table[] = {
        { 0x0, 4 }, /* Yep, really. Aspeed confirmed this is correct */
        { 0x1, 4 },
        { 0x2, 6 },
        { 0x3, 8 },
        { 0x4, 10 },
        { 0x5, 12 },
        { 0x6, 14 },
        { 0x7, 16 },
        { 0 }
};

static const struct clk_div_table ast2400_div_table[] = {
        { 0x0, 2 },
        { 0x1, 4 },
        { 0x2, 6 },
        { 0x3, 8 },
        { 0x4, 10 },
        { 0x5, 12 },
        { 0x6, 14 },
        { 0x7, 16 },
        { 0 }
};

static const struct clk_div_table ast2500_div_table[] = {
        { 0x0, 4 },
        { 0x1, 8 },
        { 0x2, 12 },
        { 0x3, 16 },
        { 0x4, 20 },
        { 0x5, 24 },
        { 0x6, 28 },
        { 0x7, 32 },
        { 0 }
};

static struct clk_hw *aspeed_ast2400_calc_pll(const char *name, u32 val)
{
        unsigned int mult, div;

        if (val & AST2400_HPLL_BYPASS_EN) {
                /* Pass through mode */
                mult = div = 1;
        } else {
                /* F = 24Mhz * (2-OD) * [(N + 2) / (D + 1)] */
                u32 n = (val >> 5) & 0x3f;
                u32 od = (val >> 4) & 0x1;
                u32 d = val & 0xf;

                mult = (2 - od) * (n + 2);
                div = d + 1;
        }
        return clk_hw_register_fixed_factor(NULL, name, "clkin", 0,
                        mult, div);
};

static struct clk_hw *aspeed_ast2500_calc_pll(const char *name, u32 val)
{
        unsigned int mult, div;

        if (val & AST2500_HPLL_BYPASS_EN) {
                /* Pass through mode */
                mult = div = 1;
        } else {
                /* F = clkin * [(M+1) / (N+1)] / (P + 1) */
                u32 p = (val >> 13) & 0x3f;
                u32 m = (val >> 5) & 0xff;
                u32 n = val & 0x1f;

                mult = (m + 1) / (n + 1);
                div = p + 1;
        }

        return clk_hw_register_fixed_factor(NULL, name, "clkin", 0,
                        mult, div);
}

struct aspeed_clk_soc_data {
        const struct clk_div_table *div_table;
        const struct clk_div_table *mac_div_table;
        struct clk_hw *(*calc_pll)(const char *name, u32 val);
};

static const struct aspeed_clk_soc_data ast2500_data = {
        .div_table = ast2500_div_table,
        .mac_div_table = ast2500_mac_div_table,
        .calc_pll = aspeed_ast2500_calc_pll,
};

static const struct aspeed_clk_soc_data ast2400_data = {
        .div_table = ast2400_div_table,
        .mac_div_table = ast2400_div_table,
        .calc_pll = aspeed_ast2400_calc_pll,
};

static int aspeed_clk_is_enabled(struct clk_hw *hw)
{
        struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
        u32 clk = BIT(gate->clock_idx);
        u32 rst = BIT(gate->reset_idx);
        u32 enval = (gate->flags & CLK_GATE_SET_TO_DISABLE) ? 0 : clk;
        u32 reg;

        /*
         * If the IP is in reset, treat the clock as not enabled,
         * this happens with some clocks such as the USB one when
         * coming from cold reset. Without this, aspeed_clk_enable()
         * will fail to lift the reset.
         */
        if (gate->reset_idx >= 0) {
                regmap_read(gate->map, ASPEED_RESET_CTRL, &reg);
                if (reg & rst)
                        return 0;
        }

        regmap_read(gate->map, ASPEED_CLK_STOP_CTRL, &reg);

        return ((reg & clk) == enval) ? 1 : 0;
}

static int aspeed_clk_enable(struct clk_hw *hw)
{
        struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
        unsigned long flags;
        u32 clk = BIT(gate->clock_idx);
        u32 rst = BIT(gate->reset_idx);
        u32 enval;

        spin_lock_irqsave(gate->lock, flags);

        if (aspeed_clk_is_enabled(hw)) {
                spin_unlock_irqrestore(gate->lock, flags);
                return 0;
        }

        if (gate->reset_idx >= 0) {
                /* Put IP in reset */
                regmap_update_bits(gate->map, ASPEED_RESET_CTRL, rst, rst);

                /* Delay 100us */
                udelay(100);
        }

        /* Enable clock */
        enval = (gate->flags & CLK_GATE_SET_TO_DISABLE) ? 0 : clk;
        regmap_update_bits(gate->map, ASPEED_CLK_STOP_CTRL, clk, enval);

        if (gate->reset_idx >= 0) {
                /* A delay of 10ms is specified by the ASPEED docs */
                mdelay(10);

                /* Take IP out of reset */
                regmap_update_bits(gate->map, ASPEED_RESET_CTRL, rst, 0);
        }

        spin_unlock_irqrestore(gate->lock, flags);

        return 0;
}

static void aspeed_clk_disable(struct clk_hw *hw)
{
        struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
        unsigned long flags;
        u32 clk = BIT(gate->clock_idx);
        u32 enval;

        spin_lock_irqsave(gate->lock, flags);

        enval = (gate->flags & CLK_GATE_SET_TO_DISABLE) ? clk : 0;
        regmap_update_bits(gate->map, ASPEED_CLK_STOP_CTRL, clk, enval);

        spin_unlock_irqrestore(gate->lock, flags);
}

static const struct clk_ops aspeed_clk_gate_ops = {
        .enable = aspeed_clk_enable,
        .disable = aspeed_clk_disable,
        .is_enabled = aspeed_clk_is_enabled,
};

/**
 * struct aspeed_reset - Aspeed reset controller
 * @map: regmap to access the containing system controller
 * @rcdev: reset controller device
 */
struct aspeed_reset {
        struct regmap                   *map;
        struct reset_controller_dev     rcdev;
};

#define to_aspeed_reset(p) container_of((p), struct aspeed_reset, rcdev)

static const u8 aspeed_resets[] = {
        /* SCU04 resets */
        [ASPEED_RESET_XDMA]     = 25,
        [ASPEED_RESET_MCTP]     = 24,
        [ASPEED_RESET_ADC]      = 23,
        [ASPEED_RESET_JTAG_MASTER] = 22,
        [ASPEED_RESET_MIC]      = 18,
        [ASPEED_RESET_PWM]      =  9,
        [ASPEED_RESET_PECI]     = 10,
        [ASPEED_RESET_I2C]      =  2,
        [ASPEED_RESET_AHB]      =  1,

        /*
         * SCUD4 resets start at an offset to separate them from
         * the SCU04 resets.
         */
        [ASPEED_RESET_CRT1]     = ASPEED_RESET2_OFFSET + 5,
};

static int aspeed_reset_deassert(struct reset_controller_dev *rcdev,
                                 unsigned long id)
{
        struct aspeed_reset *ar = to_aspeed_reset(rcdev);
        u32 reg = ASPEED_RESET_CTRL;
        u32 bit = aspeed_resets[id];

        if (bit >= ASPEED_RESET2_OFFSET) {
                bit -= ASPEED_RESET2_OFFSET;
                reg = ASPEED_RESET_CTRL2;
        }

        return regmap_update_bits(ar->map, reg, BIT(bit), 0);
}

static int aspeed_reset_assert(struct reset_controller_dev *rcdev,
                               unsigned long id)
{
        struct aspeed_reset *ar = to_aspeed_reset(rcdev);
        u32 reg = ASPEED_RESET_CTRL;
        u32 bit = aspeed_resets[id];

        if (bit >= ASPEED_RESET2_OFFSET) {
                bit -= ASPEED_RESET2_OFFSET;
                reg = ASPEED_RESET_CTRL2;
        }

        return regmap_update_bits(ar->map, reg, BIT(bit), BIT(bit));
}

static int aspeed_reset_status(struct reset_controller_dev *rcdev,
                               unsigned long id)
{
        struct aspeed_reset *ar = to_aspeed_reset(rcdev);
        u32 reg = ASPEED_RESET_CTRL;
        u32 bit = aspeed_resets[id];
        int ret, val;

        if (bit >= ASPEED_RESET2_OFFSET) {
                bit -= ASPEED_RESET2_OFFSET;
                reg = ASPEED_RESET_CTRL2;
        }

        ret = regmap_read(ar->map, reg, &val);
        if (ret)
                return ret;

        return !!(val & BIT(bit));
}

static const struct reset_control_ops aspeed_reset_ops = {
        .assert = aspeed_reset_assert,
        .deassert = aspeed_reset_deassert,
        .status = aspeed_reset_status,
};

static struct clk_hw *aspeed_clk_hw_register_gate(struct device *dev,
                const char *name, const char *parent_name, unsigned long flags,
                struct regmap *map, u8 clock_idx, u8 reset_idx,
                u8 clk_gate_flags, spinlock_t *lock)
{
        struct aspeed_clk_gate *gate;
        struct clk_init_data init;
        struct clk_hw *hw;
        int ret;

        gate = kzalloc(sizeof(*gate), GFP_KERNEL);
        if (!gate)
                return ERR_PTR(-ENOMEM);

        init.name = name;
        init.ops = &aspeed_clk_gate_ops;
        init.flags = flags;
        init.parent_names = parent_name ? &parent_name : NULL;
        init.num_parents = parent_name ? 1 : 0;

        gate->map = map;
        gate->clock_idx = clock_idx;
        gate->reset_idx = reset_idx;
        gate->flags = clk_gate_flags;
        gate->lock = lock;
        gate->hw.init = &init;

        hw = &gate->hw;
        ret = clk_hw_register(dev, hw);
        if (ret) {
                kfree(gate);
                hw = ERR_PTR(ret);
        }

        return hw;
}

static int aspeed_clk_probe(struct platform_device *pdev)
{
        const struct aspeed_clk_soc_data *soc_data;
        struct device *dev = &pdev->dev;
        struct aspeed_reset *ar;
        struct regmap *map;
        struct clk_hw *hw;
        u32 val, rate;
        int i, ret;

        map = syscon_node_to_regmap(dev->of_node);
        if (IS_ERR(map)) {
                dev_err(dev, "no syscon regmap\n");
                return PTR_ERR(map);
        }

        ar = devm_kzalloc(dev, sizeof(*ar), GFP_KERNEL);
        if (!ar)
                return -ENOMEM;

        ar->map = map;
        ar->rcdev.owner = THIS_MODULE;
        ar->rcdev.nr_resets = ARRAY_SIZE(aspeed_resets);
        ar->rcdev.ops = &aspeed_reset_ops;
        ar->rcdev.of_node = dev->of_node;

        ret = devm_reset_controller_register(dev, &ar->rcdev);
        if (ret) {
                dev_err(dev, "could not register reset controller\n");
                return ret;
        }

        /* SoC generations share common layouts but have different divisors */
        soc_data = of_device_get_match_data(dev);
        if (!soc_data) {
                dev_err(dev, "no match data for platform\n");
                return -EINVAL;
        }

        /* UART clock div13 setting */
        regmap_read(map, ASPEED_MISC_CTRL, &val);
        if (val & UART_DIV13_EN)
                rate = 24000000 / 13;
        else
                rate = 24000000;
        /* TODO: Find the parent data for the uart clock */
        hw = clk_hw_register_fixed_rate(dev, "uart", NULL, 0, rate);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_UART] = hw;

        /*
         * Memory controller (M-PLL) PLL. This clock is configured by the
         * bootloader, and is exposed to Linux as a read-only clock rate.
         */
        regmap_read(map, ASPEED_MPLL_PARAM, &val);
        hw = soc_data->calc_pll("mpll", val);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_MPLL] = hw;

        /* SD/SDIO clock divider (TODO: There's a gate too) */
        hw = clk_hw_register_divider_table(dev, "sdio", "hpll", 0,
                        scu_base + ASPEED_CLK_SELECTION, 12, 3, 0,
                        soc_data->div_table,
                        &aspeed_clk_lock);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_SDIO] = hw;

        /* MAC AHB bus clock divider */
        hw = clk_hw_register_divider_table(dev, "mac", "hpll", 0,
                        scu_base + ASPEED_CLK_SELECTION, 16, 3, 0,
                        soc_data->mac_div_table,
                        &aspeed_clk_lock);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_MAC] = hw;

        /* LPC Host (LHCLK) clock divider */
        hw = clk_hw_register_divider_table(dev, "lhclk", "hpll", 0,
                        scu_base + ASPEED_CLK_SELECTION, 20, 3, 0,
                        soc_data->div_table,
                        &aspeed_clk_lock);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_LHCLK] = hw;

        /* P-Bus (BCLK) clock divider */
        hw = clk_hw_register_divider_table(dev, "bclk", "hpll", 0,
                        scu_base + ASPEED_CLK_SELECTION_2, 0, 2, 0,
                        soc_data->div_table,
                        &aspeed_clk_lock);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_BCLK] = hw;

        /* Fixed 24MHz clock */
        hw = clk_hw_register_fixed_rate(NULL, "fixed-24m", "clkin",
                                        0, 24000000);
        if (IS_ERR(hw))
                return PTR_ERR(hw);
        aspeed_clk_data->hws[ASPEED_CLK_24M] = hw;

        /*
         * TODO: There are a number of clocks that not included in this driver
         * as more information is required:
         *   D2-PLL
         *   D-PLL
         *   YCLK
         *   RGMII
         *   RMII
         *   UART[1..5] clock source mux
         *   Video Engine (ECLK) mux and clock divider
         */

        for (i = 0; i < ARRAY_SIZE(aspeed_gates); i++) {
                const struct aspeed_gate_data *gd = &aspeed_gates[i];
                u32 gate_flags;

                /* Special case: the USB port 1 clock (bit 14) is always
                 * working the opposite way from the other ones.
                 */
                gate_flags = (gd->clock_idx == 14) ? 0 : CLK_GATE_SET_TO_DISABLE;
                hw = aspeed_clk_hw_register_gate(dev,
                                gd->name,
                                gd->parent_name,
                                gd->flags,
                                map,
                                gd->clock_idx,
                                gd->reset_idx,
                                gate_flags,
                                &aspeed_clk_lock);
                if (IS_ERR(hw))
                        return PTR_ERR(hw);
                aspeed_clk_data->hws[i] = hw;
        }

        return 0;
};

static const struct of_device_id aspeed_clk_dt_ids[] = {
        { .compatible = "aspeed,ast2400-scu", .data = &ast2400_data },
        { .compatible = "aspeed,ast2500-scu", .data = &ast2500_data },
        { }
};

static struct platform_driver aspeed_clk_driver = {
        .probe  = aspeed_clk_probe,
        .driver = {
                .name = "aspeed-clk",
                .of_match_table = aspeed_clk_dt_ids,
                .suppress_bind_attrs = true,
        },
};
builtin_platform_driver(aspeed_clk_driver);

static void __init aspeed_ast2400_cc(struct regmap *map)
{
        struct clk_hw *hw;
        u32 val, div, clkin, hpll;
        const u16 hpll_rates[][4] = {
                {384, 360, 336, 408},
                {400, 375, 350, 425},
        };
        int rate;

        /*
         * CLKIN is the crystal oscillator, 24, 48 or 25MHz selected by
         * strapping
         */
        regmap_read(map, ASPEED_STRAP, &val);
        rate = (val >> 8) & 3;
        if (val & CLKIN_25MHZ_EN) {
                clkin = 25000000;
                hpll = hpll_rates[1][rate];
        } else if (val & AST2400_CLK_SOURCE_SEL) {
                clkin = 48000000;
                hpll = hpll_rates[0][rate];
        } else {
                clkin = 24000000;
                hpll = hpll_rates[0][rate];
        }
        hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, clkin);
        pr_debug("clkin @%u MHz\n", clkin / 1000000);

        /*
         * High-speed PLL clock derived from the crystal. This the CPU clock,
         * and we assume that it is enabled. It can be configured through the
         * HPLL_PARAM register, or set to a specified frequency by strapping.
         */
        regmap_read(map, ASPEED_HPLL_PARAM, &val);
        if (val & AST2400_HPLL_PROGRAMMED)
                hw = aspeed_ast2400_calc_pll("hpll", val);
        else
                hw = clk_hw_register_fixed_rate(NULL, "hpll", "clkin", 0,
                                hpll * 1000000);

        aspeed_clk_data->hws[ASPEED_CLK_HPLL] = hw;

        /*
         * Strap bits 11:10 define the CPU/AHB clock frequency ratio (aka HCLK)
         *   00: Select CPU:AHB = 1:1
         *   01: Select CPU:AHB = 2:1
         *   10: Select CPU:AHB = 4:1
         *   11: Select CPU:AHB = 3:1
         */
        regmap_read(map, ASPEED_STRAP, &val);
        val = (val >> 10) & 0x3;
        div = val + 1;
        if (div == 3)
                div = 4;
        else if (div == 4)
                div = 3;
        hw = clk_hw_register_fixed_factor(NULL, "ahb", "hpll", 0, 1, div);
        aspeed_clk_data->hws[ASPEED_CLK_AHB] = hw;

        /* APB clock clock selection register SCU08 (aka PCLK) */
        hw = clk_hw_register_divider_table(NULL, "apb", "hpll", 0,
                        scu_base + ASPEED_CLK_SELECTION, 23, 3, 0,
                        ast2400_div_table,
                        &aspeed_clk_lock);
        aspeed_clk_data->hws[ASPEED_CLK_APB] = hw;
}

static void __init aspeed_ast2500_cc(struct regmap *map)
{
        struct clk_hw *hw;
        u32 val, freq, div;

        /* CLKIN is the crystal oscillator, 24 or 25MHz selected by strapping */
        regmap_read(map, ASPEED_STRAP, &val);
        if (val & CLKIN_25MHZ_EN)
                freq = 25000000;
        else
                freq = 24000000;
        hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, freq);
        pr_debug("clkin @%u MHz\n", freq / 1000000);

        /*
         * High-speed PLL clock derived from the crystal. This the CPU clock,
         * and we assume that it is enabled
         */
        regmap_read(map, ASPEED_HPLL_PARAM, &val);
        aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2500_calc_pll("hpll", val);

        /* Strap bits 11:9 define the AXI/AHB clock frequency ratio (aka HCLK)*/
        regmap_read(map, ASPEED_STRAP, &val);
        val = (val >> 9) & 0x7;
        WARN(val == 0, "strapping is zero: cannot determine ahb clock");
        div = 2 * (val + 1);
        hw = clk_hw_register_fixed_factor(NULL, "ahb", "hpll", 0, 1, div);
        aspeed_clk_data->hws[ASPEED_CLK_AHB] = hw;

        /* APB clock clock selection register SCU08 (aka PCLK) */
        regmap_read(map, ASPEED_CLK_SELECTION, &val);
        val = (val >> 23) & 0x7;
        div = 4 * (val + 1);
        hw = clk_hw_register_fixed_factor(NULL, "apb", "hpll", 0, 1, div);
        aspeed_clk_data->hws[ASPEED_CLK_APB] = hw;
};

static void __init aspeed_cc_init(struct device_node *np)
{
        struct regmap *map;
        u32 val;
        int ret;
        int i;

        scu_base = of_iomap(np, 0);
        if (!scu_base)
                return;

        aspeed_clk_data = kzalloc(struct_size(aspeed_clk_data, hws,
                                              ASPEED_NUM_CLKS),
                                  GFP_KERNEL);
        if (!aspeed_clk_data)
                return;

        /*
         * This way all clocks fetched before the platform device probes,
         * except those we assign here for early use, will be deferred.
         */
        for (i = 0; i < ASPEED_NUM_CLKS; i++)
                aspeed_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);

        map = syscon_node_to_regmap(np);
        if (IS_ERR(map)) {
                pr_err("no syscon regmap\n");
                return;
        }
        /*
         * We check that the regmap works on this very first access,
         * but as this is an MMIO-backed regmap, subsequent regmap
         * access is not going to fail and we skip error checks from
         * this point.
         */
        ret = regmap_read(map, ASPEED_STRAP, &val);
        if (ret) {
                pr_err("failed to read strapping register\n");
                return;
        }

        if (of_device_is_compatible(np, "aspeed,ast2400-scu"))
                aspeed_ast2400_cc(map);
        else if (of_device_is_compatible(np, "aspeed,ast2500-scu"))
                aspeed_ast2500_cc(map);
        else
                pr_err("unknown platform, failed to add clocks\n");

        aspeed_clk_data->num = ASPEED_NUM_CLKS;
        ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, aspeed_clk_data);
        if (ret)
                pr_err("failed to add DT provider: %d\n", ret);
};
CLK_OF_DECLARE_DRIVER(aspeed_cc_g5, "aspeed,ast2500-scu", aspeed_cc_init);
CLK_OF_DECLARE_DRIVER(aspeed_cc_g4, "aspeed,ast2400-scu", aspeed_cc_init);