// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2010 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * CPU frequency scaling for S5PC110/S5PV210
*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/cpufreq.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/regulator/consumer.h>

static void __iomem *clk_base;
static void __iomem *dmc_base[2];

#define S5P_CLKREG(x)           (clk_base + (x))

#define S5P_APLL_LOCK           S5P_CLKREG(0x00)
#define S5P_APLL_CON            S5P_CLKREG(0x100)
#define S5P_CLK_SRC0            S5P_CLKREG(0x200)
#define S5P_CLK_SRC2            S5P_CLKREG(0x208)
#define S5P_CLK_DIV0            S5P_CLKREG(0x300)
#define S5P_CLK_DIV2            S5P_CLKREG(0x308)
#define S5P_CLK_DIV6            S5P_CLKREG(0x318)
#define S5P_CLKDIV_STAT0        S5P_CLKREG(0x1000)
#define S5P_CLKDIV_STAT1        S5P_CLKREG(0x1004)
#define S5P_CLKMUX_STAT0        S5P_CLKREG(0x1100)
#define S5P_CLKMUX_STAT1        S5P_CLKREG(0x1104)

#define S5P_ARM_MCS_CON         S5P_CLKREG(0x6100)

/* CLKSRC0 */
#define S5P_CLKSRC0_MUX200_SHIFT        (16)
#define S5P_CLKSRC0_MUX200_MASK         (0x1 << S5P_CLKSRC0_MUX200_SHIFT)
#define S5P_CLKSRC0_MUX166_MASK         (0x1<<20)
#define S5P_CLKSRC0_MUX133_MASK         (0x1<<24)

/* CLKSRC2 */
#define S5P_CLKSRC2_G3D_SHIFT           (0)
#define S5P_CLKSRC2_G3D_MASK            (0x3 << S5P_CLKSRC2_G3D_SHIFT)
#define S5P_CLKSRC2_MFC_SHIFT           (4)
#define S5P_CLKSRC2_MFC_MASK            (0x3 << S5P_CLKSRC2_MFC_SHIFT)

/* CLKDIV0 */
#define S5P_CLKDIV0_APLL_SHIFT          (0)
#define S5P_CLKDIV0_APLL_MASK           (0x7 << S5P_CLKDIV0_APLL_SHIFT)
#define S5P_CLKDIV0_A2M_SHIFT           (4)
#define S5P_CLKDIV0_A2M_MASK            (0x7 << S5P_CLKDIV0_A2M_SHIFT)
#define S5P_CLKDIV0_HCLK200_SHIFT       (8)
#define S5P_CLKDIV0_HCLK200_MASK        (0x7 << S5P_CLKDIV0_HCLK200_SHIFT)
#define S5P_CLKDIV0_PCLK100_SHIFT       (12)
#define S5P_CLKDIV0_PCLK100_MASK        (0x7 << S5P_CLKDIV0_PCLK100_SHIFT)
#define S5P_CLKDIV0_HCLK166_SHIFT       (16)
#define S5P_CLKDIV0_HCLK166_MASK        (0xF << S5P_CLKDIV0_HCLK166_SHIFT)
#define S5P_CLKDIV0_PCLK83_SHIFT        (20)
#define S5P_CLKDIV0_PCLK83_MASK         (0x7 << S5P_CLKDIV0_PCLK83_SHIFT)
#define S5P_CLKDIV0_HCLK133_SHIFT       (24)
#define S5P_CLKDIV0_HCLK133_MASK        (0xF << S5P_CLKDIV0_HCLK133_SHIFT)
#define S5P_CLKDIV0_PCLK66_SHIFT        (28)
#define S5P_CLKDIV0_PCLK66_MASK         (0x7 << S5P_CLKDIV0_PCLK66_SHIFT)

/* CLKDIV2 */
#define S5P_CLKDIV2_G3D_SHIFT           (0)
#define S5P_CLKDIV2_G3D_MASK            (0xF << S5P_CLKDIV2_G3D_SHIFT)
#define S5P_CLKDIV2_MFC_SHIFT           (4)
#define S5P_CLKDIV2_MFC_MASK            (0xF << S5P_CLKDIV2_MFC_SHIFT)

/* CLKDIV6 */
#define S5P_CLKDIV6_ONEDRAM_SHIFT       (28)
#define S5P_CLKDIV6_ONEDRAM_MASK        (0xF << S5P_CLKDIV6_ONEDRAM_SHIFT)

static struct clk *dmc0_clk;
static struct clk *dmc1_clk;
static DEFINE_MUTEX(set_freq_lock);

/* APLL M,P,S values for 1G/800Mhz */
#define APLL_VAL_1000   ((1 << 31) | (125 << 16) | (3 << 8) | 1)
#define APLL_VAL_800    ((1 << 31) | (100 << 16) | (3 << 8) | 1)

/* Use 800MHz when entering sleep mode */
#define SLEEP_FREQ      (800 * 1000)

/* Tracks if CPU frequency can be updated anymore */
static bool no_cpufreq_access;

/*
 * DRAM configurations to calculate refresh counter for changing
 * frequency of memory.
 */
struct dram_conf {
        unsigned long freq;     /* HZ */
        unsigned long refresh;  /* DRAM refresh counter * 1000 */
};

/* DRAM configuration (DMC0 and DMC1) */
static struct dram_conf s5pv210_dram_conf[2];

enum perf_level {
        L0, L1, L2, L3, L4,
};

enum s5pv210_mem_type {
        LPDDR   = 0x1,
        LPDDR2  = 0x2,
        DDR2    = 0x4,
};

enum s5pv210_dmc_port {
        DMC0 = 0,
        DMC1,
};

static struct cpufreq_frequency_table s5pv210_freq_table[] = {
        {0, L0, 1000*1000},
        {0, L1, 800*1000},
        {0, L2, 400*1000},
        {0, L3, 200*1000},
        {0, L4, 100*1000},
        {0, 0, CPUFREQ_TABLE_END},
};

static struct regulator *arm_regulator;
static struct regulator *int_regulator;

struct s5pv210_dvs_conf {
        int arm_volt;   /* uV */
        int int_volt;   /* uV */
};

static const int arm_volt_max = 1350000;
static const int int_volt_max = 1250000;

static struct s5pv210_dvs_conf dvs_conf[] = {
        [L0] = {
                .arm_volt       = 1250000,
                .int_volt       = 1100000,
        },
        [L1] = {
                .arm_volt       = 1200000,
                .int_volt       = 1100000,
        },
        [L2] = {
                .arm_volt       = 1050000,
                .int_volt       = 1100000,
        },
        [L3] = {
                .arm_volt       = 950000,
                .int_volt       = 1100000,
        },
        [L4] = {
                .arm_volt       = 950000,
                .int_volt       = 1000000,
        },
};

static u32 clkdiv_val[5][11] = {
        /*
         * Clock divider value for following
         * { APLL, A2M, HCLK_MSYS, PCLK_MSYS,
         *   HCLK_DSYS, PCLK_DSYS, HCLK_PSYS, PCLK_PSYS,
         *   ONEDRAM, MFC, G3D }
         */

        /* L0 : [1000/200/100][166/83][133/66][200/200] */
        {0, 4, 4, 1, 3, 1, 4, 1, 3, 0, 0},

        /* L1 : [800/200/100][166/83][133/66][200/200] */
        {0, 3, 3, 1, 3, 1, 4, 1, 3, 0, 0},

        /* L2 : [400/200/100][166/83][133/66][200/200] */
        {1, 3, 1, 1, 3, 1, 4, 1, 3, 0, 0},

        /* L3 : [200/200/100][166/83][133/66][200/200] */
        {3, 3, 1, 1, 3, 1, 4, 1, 3, 0, 0},

        /* L4 : [100/100/100][83/83][66/66][100/100] */
        {7, 7, 0, 0, 7, 0, 9, 0, 7, 0, 0},
};

/*
 * This function set DRAM refresh counter
 * according to operating frequency of DRAM
 * ch: DMC port number 0 or 1
 * freq: Operating frequency of DRAM(KHz)
 */
static void s5pv210_set_refresh(enum s5pv210_dmc_port ch, unsigned long freq)
{
        unsigned long tmp, tmp1;
        void __iomem *reg = NULL;

        if (ch == DMC0) {
                reg = (dmc_base[0] + 0x30);
        } else if (ch == DMC1) {
                reg = (dmc_base[1] + 0x30);
        } else {
                pr_err("Cannot find DMC port\n");
                return;
        }

        /* Find current DRAM frequency */
        tmp = s5pv210_dram_conf[ch].freq;

        tmp /= freq;

        tmp1 = s5pv210_dram_conf[ch].refresh;

        tmp1 /= tmp;

        writel_relaxed(tmp1, reg);
}

static int s5pv210_target(struct cpufreq_policy *policy, unsigned int index)
{
        unsigned long reg;
        unsigned int priv_index;
        unsigned int pll_changing = 0;
        unsigned int bus_speed_changing = 0;
        unsigned int old_freq, new_freq;
        int arm_volt, int_volt;
        int ret = 0;

        mutex_lock(&set_freq_lock);

        if (no_cpufreq_access) {
                pr_err("Denied access to %s as it is disabled temporarily\n",
                       __func__);
                ret = -EINVAL;
                goto exit;
        }

        old_freq = policy->cur;
        new_freq = s5pv210_freq_table[index].frequency;

        /* Finding current running level index */
        priv_index = cpufreq_table_find_index_h(policy, old_freq, false);

        arm_volt = dvs_conf[index].arm_volt;
        int_volt = dvs_conf[index].int_volt;

        if (new_freq > old_freq) {
                ret = regulator_set_voltage(arm_regulator,
                                arm_volt, arm_volt_max);
                if (ret)
                        goto exit;

                ret = regulator_set_voltage(int_regulator,
                                int_volt, int_volt_max);
                if (ret)
                        goto exit;
        }

        /* Check if there need to change PLL */
        if ((index == L0) || (priv_index == L0))
                pll_changing = 1;

        /* Check if there need to change System bus clock */
        if ((index == L4) || (priv_index == L4))
                bus_speed_changing = 1;

        if (bus_speed_changing) {
                /*
                 * Reconfigure DRAM refresh counter value for minimum
                 * temporary clock while changing divider.
                 * expected clock is 83Mhz : 7.8usec/(1/83Mhz) = 0x287
                 */
                if (pll_changing)
                        s5pv210_set_refresh(DMC1, 83000);
                else
                        s5pv210_set_refresh(DMC1, 100000);

                s5pv210_set_refresh(DMC0, 83000);
        }

        /*
         * APLL should be changed in this level
         * APLL -> MPLL(for stable transition) -> APLL
         * Some clock source's clock API are not prepared.
         * Do not use clock API in below code.
         */
        if (pll_changing) {
                /*
                 * 1. Temporary Change divider for MFC and G3D
                 * SCLKA2M(200/1=200)->(200/4=50)Mhz
                 */
                reg = readl_relaxed(S5P_CLK_DIV2);
                reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
                reg |= (3 << S5P_CLKDIV2_G3D_SHIFT) |
                        (3 << S5P_CLKDIV2_MFC_SHIFT);
                writel_relaxed(reg, S5P_CLK_DIV2);

                /* For MFC, G3D dividing */
                do {
                        reg = readl_relaxed(S5P_CLKDIV_STAT0);
                } while (reg & ((1 << 16) | (1 << 17)));

                /*
                 * 2. Change SCLKA2M(200Mhz)to SCLKMPLL in MFC_MUX, G3D MUX
                 * (200/4=50)->(667/4=166)Mhz
                 */
                reg = readl_relaxed(S5P_CLK_SRC2);
                reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
                reg |= (1 << S5P_CLKSRC2_G3D_SHIFT) |
                        (1 << S5P_CLKSRC2_MFC_SHIFT);
                writel_relaxed(reg, S5P_CLK_SRC2);

                do {
                        reg = readl_relaxed(S5P_CLKMUX_STAT1);
                } while (reg & ((1 << 7) | (1 << 3)));

                /*
                 * 3. DMC1 refresh count for 133Mhz if (index == L4) is
                 * true refresh counter is already programmed in upper
                 * code. 0x287@83Mhz
                 */
                if (!bus_speed_changing)
                        s5pv210_set_refresh(DMC1, 133000);

                /* 4. SCLKAPLL -> SCLKMPLL */
                reg = readl_relaxed(S5P_CLK_SRC0);
                reg &= ~(S5P_CLKSRC0_MUX200_MASK);
                reg |= (0x1 << S5P_CLKSRC0_MUX200_SHIFT);
                writel_relaxed(reg, S5P_CLK_SRC0);

                do {
                        reg = readl_relaxed(S5P_CLKMUX_STAT0);
                } while (reg & (0x1 << 18));

        }

        /* Change divider */
        reg = readl_relaxed(S5P_CLK_DIV0);

        reg &= ~(S5P_CLKDIV0_APLL_MASK | S5P_CLKDIV0_A2M_MASK |
                S5P_CLKDIV0_HCLK200_MASK | S5P_CLKDIV0_PCLK100_MASK |
                S5P_CLKDIV0_HCLK166_MASK | S5P_CLKDIV0_PCLK83_MASK |
                S5P_CLKDIV0_HCLK133_MASK | S5P_CLKDIV0_PCLK66_MASK);

        reg |= ((clkdiv_val[index][0] << S5P_CLKDIV0_APLL_SHIFT) |
                (clkdiv_val[index][1] << S5P_CLKDIV0_A2M_SHIFT) |
                (clkdiv_val[index][2] << S5P_CLKDIV0_HCLK200_SHIFT) |
                (clkdiv_val[index][3] << S5P_CLKDIV0_PCLK100_SHIFT) |
                (clkdiv_val[index][4] << S5P_CLKDIV0_HCLK166_SHIFT) |
                (clkdiv_val[index][5] << S5P_CLKDIV0_PCLK83_SHIFT) |
                (clkdiv_val[index][6] << S5P_CLKDIV0_HCLK133_SHIFT) |
                (clkdiv_val[index][7] << S5P_CLKDIV0_PCLK66_SHIFT));

        writel_relaxed(reg, S5P_CLK_DIV0);

        do {
                reg = readl_relaxed(S5P_CLKDIV_STAT0);
        } while (reg & 0xff);

        /* ARM MCS value changed */
        reg = readl_relaxed(S5P_ARM_MCS_CON);
        reg &= ~0x3;
        if (index >= L3)
                reg |= 0x3;
        else
                reg |= 0x1;

        writel_relaxed(reg, S5P_ARM_MCS_CON);

        if (pll_changing) {
                /* 5. Set Lock time = 30us*24Mhz = 0x2cf */
                writel_relaxed(0x2cf, S5P_APLL_LOCK);

                /*
                 * 6. Turn on APLL
                 * 6-1. Set PMS values
                 * 6-2. Wait until the PLL is locked
                 */
                if (index == L0)
                        writel_relaxed(APLL_VAL_1000, S5P_APLL_CON);
                else
                        writel_relaxed(APLL_VAL_800, S5P_APLL_CON);

                do {
                        reg = readl_relaxed(S5P_APLL_CON);
                } while (!(reg & (0x1 << 29)));

                /*
                 * 7. Change source clock from SCLKMPLL(667Mhz)
                 * to SCLKA2M(200Mhz) in MFC_MUX and G3D MUX
                 * (667/4=166)->(200/4=50)Mhz
                 */
                reg = readl_relaxed(S5P_CLK_SRC2);
                reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
                reg |= (0 << S5P_CLKSRC2_G3D_SHIFT) |
                        (0 << S5P_CLKSRC2_MFC_SHIFT);
                writel_relaxed(reg, S5P_CLK_SRC2);

                do {
                        reg = readl_relaxed(S5P_CLKMUX_STAT1);
                } while (reg & ((1 << 7) | (1 << 3)));

                /*
                 * 8. Change divider for MFC and G3D
                 * (200/4=50)->(200/1=200)Mhz
                 */
                reg = readl_relaxed(S5P_CLK_DIV2);
                reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
                reg |= (clkdiv_val[index][10] << S5P_CLKDIV2_G3D_SHIFT) |
                        (clkdiv_val[index][9] << S5P_CLKDIV2_MFC_SHIFT);
                writel_relaxed(reg, S5P_CLK_DIV2);

                /* For MFC, G3D dividing */
                do {
                        reg = readl_relaxed(S5P_CLKDIV_STAT0);
                } while (reg & ((1 << 16) | (1 << 17)));

                /* 9. Change MPLL to APLL in MSYS_MUX */
                reg = readl_relaxed(S5P_CLK_SRC0);
                reg &= ~(S5P_CLKSRC0_MUX200_MASK);
                reg |= (0x0 << S5P_CLKSRC0_MUX200_SHIFT);
                writel_relaxed(reg, S5P_CLK_SRC0);

                do {
                        reg = readl_relaxed(S5P_CLKMUX_STAT0);
                } while (reg & (0x1 << 18));

                /*
                 * 10. DMC1 refresh counter
                 * L4 : DMC1 = 100Mhz 7.8us/(1/100) = 0x30c
                 * Others : DMC1 = 200Mhz 7.8us/(1/200) = 0x618
                 */
                if (!bus_speed_changing)
                        s5pv210_set_refresh(DMC1, 200000);
        }

        /*
         * L4 level needs to change memory bus speed, hence ONEDRAM clock
         * divider and memory refresh parameter should be changed
         */
        if (bus_speed_changing) {
                reg = readl_relaxed(S5P_CLK_DIV6);
                reg &= ~S5P_CLKDIV6_ONEDRAM_MASK;
                reg |= (clkdiv_val[index][8] << S5P_CLKDIV6_ONEDRAM_SHIFT);
                writel_relaxed(reg, S5P_CLK_DIV6);

                do {
                        reg = readl_relaxed(S5P_CLKDIV_STAT1);
                } while (reg & (1 << 15));

                /* Reconfigure DRAM refresh counter value */
                if (index != L4) {
                        /*
                         * DMC0 : 166Mhz
                         * DMC1 : 200Mhz
                         */
                        s5pv210_set_refresh(DMC0, 166000);
                        s5pv210_set_refresh(DMC1, 200000);
                } else {
                        /*
                         * DMC0 : 83Mhz
                         * DMC1 : 100Mhz
                         */
                        s5pv210_set_refresh(DMC0, 83000);
                        s5pv210_set_refresh(DMC1, 100000);
                }
        }

        if (new_freq < old_freq) {
                regulator_set_voltage(int_regulator,
                                int_volt, int_volt_max);

                regulator_set_voltage(arm_regulator,
                                arm_volt, arm_volt_max);
        }

        pr_debug("Perf changed[L%d]\n", index);

exit:
        mutex_unlock(&set_freq_lock);
        return ret;
}

static int check_mem_type(void __iomem *dmc_reg)
{
        unsigned long val;

        val = readl_relaxed(dmc_reg + 0x4);
        val = (val & (0xf << 8));

        return val >> 8;
}

static int s5pv210_cpu_init(struct cpufreq_policy *policy)
{
        unsigned long mem_type;
        int ret;

        policy->clk = clk_get(NULL, "armclk");
        if (IS_ERR(policy->clk))
                return PTR_ERR(policy->clk);

        dmc0_clk = clk_get(NULL, "sclk_dmc0");
        if (IS_ERR(dmc0_clk)) {
                ret = PTR_ERR(dmc0_clk);
                goto out_dmc0;
        }

        dmc1_clk = clk_get(NULL, "hclk_msys");
        if (IS_ERR(dmc1_clk)) {
                ret = PTR_ERR(dmc1_clk);
                goto out_dmc1;
        }

        if (policy->cpu != 0) {
                ret = -EINVAL;
                goto out;
        }

        /*
         * check_mem_type : This driver only support LPDDR & LPDDR2.
         * other memory type is not supported.
         */
        mem_type = check_mem_type(dmc_base[0]);

        if ((mem_type != LPDDR) && (mem_type != LPDDR2)) {
                pr_err("CPUFreq doesn't support this memory type\n");
                ret = -EINVAL;
                goto out;
        }

        /* Find current refresh counter and frequency each DMC */
        s5pv210_dram_conf[0].refresh = (readl_relaxed(dmc_base[0] + 0x30) * 1000);
        s5pv210_dram_conf[0].freq = clk_get_rate(dmc0_clk);

        s5pv210_dram_conf[1].refresh = (readl_relaxed(dmc_base[1] + 0x30) * 1000);
        s5pv210_dram_conf[1].freq = clk_get_rate(dmc1_clk);

        policy->suspend_freq = SLEEP_FREQ;
        cpufreq_generic_init(policy, s5pv210_freq_table, 40000);
        return 0;

out:
        clk_put(dmc1_clk);
out_dmc1:
        clk_put(dmc0_clk);
out_dmc0:
        clk_put(policy->clk);
        return ret;
}

static int s5pv210_cpufreq_reboot_notifier_event(struct notifier_block *this,
                                                 unsigned long event, void *ptr)
{
        struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(0);
        int ret;

        if (!policy) {
                pr_debug("cpufreq: get no policy for cpu0\n");
                return NOTIFY_BAD;
        }

        ret = cpufreq_driver_target(policy, SLEEP_FREQ, 0);

        if (ret < 0)
                return NOTIFY_BAD;

        no_cpufreq_access = true;
        return NOTIFY_DONE;
}

static struct cpufreq_driver s5pv210_driver = {
        .flags          = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
        .verify         = cpufreq_generic_frequency_table_verify,
        .target_index   = s5pv210_target,
        .get            = cpufreq_generic_get,
        .init           = s5pv210_cpu_init,
        .name           = "s5pv210",
        .suspend        = cpufreq_generic_suspend,
        .resume         = cpufreq_generic_suspend, /* We need to set SLEEP FREQ again */
};

static struct notifier_block s5pv210_cpufreq_reboot_notifier = {
        .notifier_call = s5pv210_cpufreq_reboot_notifier_event,
};

static int s5pv210_cpufreq_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np;
        int id, result = 0;

        /*
         * HACK: This is a temporary workaround to get access to clock
         * and DMC controller registers directly and remove static mappings
         * and dependencies on platform headers. It is necessary to enable
         * S5PV210 multi-platform support and will be removed together with
         * this whole driver as soon as S5PV210 gets migrated to use
         * cpufreq-dt driver.
         */
        arm_regulator = regulator_get(NULL, "vddarm");
        if (IS_ERR(arm_regulator))
                return dev_err_probe(dev, PTR_ERR(arm_regulator),
                                     "failed to get regulator vddarm\n");

        int_regulator = regulator_get(NULL, "vddint");
        if (IS_ERR(int_regulator)) {
                result = dev_err_probe(dev, PTR_ERR(int_regulator),
                                       "failed to get regulator vddint\n");
                goto err_int_regulator;
        }

        np = of_find_compatible_node(NULL, NULL, "samsung,s5pv210-clock");
        if (!np) {
                dev_err(dev, "failed to find clock controller DT node\n");
                result = -ENODEV;
                goto err_clock;
        }

        clk_base = of_iomap(np, 0);
        of_node_put(np);
        if (!clk_base) {
                dev_err(dev, "failed to map clock registers\n");
                result = -EFAULT;
                goto err_clock;
        }

        for_each_compatible_node_scoped(dmc, NULL, "samsung,s5pv210-dmc") {
                id = of_alias_get_id(dmc, "dmc");
                if (id < 0 || id >= ARRAY_SIZE(dmc_base)) {
                        dev_err(dev, "failed to get alias of dmc node '%pOFn'\n", dmc);
                        result = id;
                        goto err_clk_base;
                }

                dmc_base[id] = of_iomap(dmc, 0);
                if (!dmc_base[id]) {
                        dev_err(dev, "failed to map dmc%d registers\n", id);
                        result = -EFAULT;
                        goto err_dmc;
                }
        }

        for (id = 0; id < ARRAY_SIZE(dmc_base); ++id) {
                if (!dmc_base[id]) {
                        dev_err(dev, "failed to find dmc%d node\n", id);
                        result = -ENODEV;
                        goto err_dmc;
                }
        }

        register_reboot_notifier(&s5pv210_cpufreq_reboot_notifier);

        return cpufreq_register_driver(&s5pv210_driver);

err_dmc:
        for (id = 0; id < ARRAY_SIZE(dmc_base); ++id)
                if (dmc_base[id]) {
                        iounmap(dmc_base[id]);
                        dmc_base[id] = NULL;
                }

err_clk_base:
        iounmap(clk_base);

err_clock:
        regulator_put(int_regulator);

err_int_regulator:
        regulator_put(arm_regulator);

        return result;
}

static struct platform_driver s5pv210_cpufreq_platdrv = {
        .driver = {
                .name   = "s5pv210-cpufreq",
        },
        .probe = s5pv210_cpufreq_probe,
};
builtin_platform_driver(s5pv210_cpufreq_platdrv);