drivers/cpufreq/s5pv210-cpufreq.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2010 Samsung Electronics Co., Ltd.
  *		http://www.samsung.com
  *
  * CPU frequency scaling for S5PC110/S5PV210
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
 */

 #include <linux/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 freqency 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
  * accoriding 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 {
 		printk(KERN_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;

 	__raw_writel(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 */
 	if (cpufreq_frequency_table_target(policy, s5pv210_freq_table,
 					   old_freq, CPUFREQ_RELATION_H,
 					   &priv_index)) {
 		ret = -EINVAL;
 		goto exit;
 	}

 	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 = __raw_readl(S5P_CLK_DIV2);
 		reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
 		reg |= (3 << S5P_CLKDIV2_G3D_SHIFT) |
 			(3 << S5P_CLKDIV2_MFC_SHIFT);
 		__raw_writel(reg, S5P_CLK_DIV2);

 		/* For MFC, G3D dividing */
 		do {
 			reg = __raw_readl(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 = __raw_readl(S5P_CLK_SRC2);
 		reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
 		reg |= (1 << S5P_CLKSRC2_G3D_SHIFT) |
 			(1 << S5P_CLKSRC2_MFC_SHIFT);
 		__raw_writel(reg, S5P_CLK_SRC2);

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

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

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

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

 	}

 	/* Change divider */
 	reg = __raw_readl(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));

 	__raw_writel(reg, S5P_CLK_DIV0);

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

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

 	__raw_writel(reg, S5P_ARM_MCS_CON);

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

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

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

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

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

 		/*
 		 * 8. Change divider for MFC and G3D
 		 * (200/4=50)->(200/1=200)Mhz
 		 */
 		reg = __raw_readl(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);
 		__raw_writel(reg, S5P_CLK_DIV2);

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

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

 		do {
 			reg = __raw_readl(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 need to change memory bus speed, hence onedram clock divier
 	 * and memory refresh parameter should be changed
 	 */
 	if (bus_speed_changing) {
 		reg = __raw_readl(S5P_CLK_DIV6);
 		reg &= ~S5P_CLKDIV6_ONEDRAM_MASK;
 		reg |= (clkdiv_val[index][8] << S5P_CLKDIV6_ONEDRAM_SHIFT);
 		__raw_writel(reg, S5P_CLK_DIV6);

 		do {
 			reg = __raw_readl(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);
 	}

 	printk(KERN_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 = __raw_readl(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_dmc1;
 	}

 	/*
 	 * 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)) {
 		printk(KERN_ERR "CPUFreq doesn't support this memory type\n");
 		ret = -EINVAL;
 		goto out_dmc1;
 	}

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

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

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

 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)
 {
 	int ret;

 	ret = cpufreq_driver_target(cpufreq_cpu_get(0), SLEEP_FREQ, 0);
 	if (ret < 0)
 		return NOTIFY_BAD;

 	no_cpufreq_access = true;
 	return NOTIFY_DONE;
 }

 static struct cpufreq_driver s5pv210_driver = {
 	.flags		= CPUFREQ_STICKY | 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_node *np;
 	int id;

 	/*
 	 * 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.
 	 */
 	np = of_find_compatible_node(NULL, NULL, "samsung,s5pv210-clock");
 	if (!np) {
 		pr_err("%s: failed to find clock controller DT node\n",
 			__func__);
 		return -ENODEV;
 	}

 	clk_base = of_iomap(np, 0);
 	if (!clk_base) {
 		pr_err("%s: failed to map clock registers\n", __func__);
 		return -EFAULT;
 	}

 	for_each_compatible_node(np, NULL, "samsung,s5pv210-dmc") {
 		id = of_alias_get_id(np, "dmc");
 		if (id < 0 || id >= ARRAY_SIZE(dmc_base)) {
 			pr_err("%s: failed to get alias of dmc node '%s'\n",
 				__func__, np->name);
 			return id;
 		}

 		dmc_base[id] = of_iomap(np, 0);
 		if (!dmc_base[id]) {
 			pr_err("%s: failed to map dmc%d registers\n",
 				__func__, id);
 			return -EFAULT;
 		}
 	}

 	for (id = 0; id < ARRAY_SIZE(dmc_base); ++id) {
 		if (!dmc_base[id]) {
 			pr_err("%s: failed to find dmc%d node\n", __func__, id);
 			return -ENODEV;
 		}
 	}

 	arm_regulator = regulator_get(NULL, "vddarm");
 	if (IS_ERR(arm_regulator)) {
 		pr_err("failed to get regulator vddarm");
 		return PTR_ERR(arm_regulator);
 	}

 	int_regulator = regulator_get(NULL, "vddint");
 	if (IS_ERR(int_regulator)) {
 		pr_err("failed to get regulator vddint");
 		regulator_put(arm_regulator);
 		return PTR_ERR(int_regulator);
 	}

 	register_reboot_notifier(&s5pv210_cpufreq_reboot_notifier);

 	return cpufreq_register_driver(&s5pv210_driver);
 }

 static struct platform_driver s5pv210_cpufreq_platdrv = {
 	.driver = {
 		.name	= "s5pv210-cpufreq",
 	},
 	.probe = s5pv210_cpufreq_probe,
 };
 builtin_platform_driver(s5pv210_cpufreq_platdrv);
	/*
	* Copyright (c) 2010 Samsung Electronics Co., Ltd.
	* http://www.samsung.com
	*
	* CPU frequency scaling for S5PC110/S5PV210
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/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 freqency 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
	* accoriding 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 {
	printk(KERN_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;

	__raw_writel(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 */
	if (cpufreq_frequency_table_target(policy, s5pv210_freq_table,
	old_freq, CPUFREQ_RELATION_H,
	&priv_index)) {
	ret = -EINVAL;
	goto exit;
	}

	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 = __raw_readl(S5P_CLK_DIV2);
	reg &= ~(S5P_CLKDIV2_G3D_MASK \| S5P_CLKDIV2_MFC_MASK);
	reg \|= (3 << S5P_CLKDIV2_G3D_SHIFT) \|
	(3 << S5P_CLKDIV2_MFC_SHIFT);
	__raw_writel(reg, S5P_CLK_DIV2);

	/* For MFC, G3D dividing */
	do {
	reg = __raw_readl(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 = __raw_readl(S5P_CLK_SRC2);
	reg &= ~(S5P_CLKSRC2_G3D_MASK \| S5P_CLKSRC2_MFC_MASK);
	reg \|= (1 << S5P_CLKSRC2_G3D_SHIFT) \|
	(1 << S5P_CLKSRC2_MFC_SHIFT);
	__raw_writel(reg, S5P_CLK_SRC2);

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

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

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

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

	}

	/* Change divider */
	reg = __raw_readl(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));

	__raw_writel(reg, S5P_CLK_DIV0);

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

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

	__raw_writel(reg, S5P_ARM_MCS_CON);

	if (pll_changing) {
	/* 5. Set Lock time = 30us24Mhz = 0x2cf /
	__raw_writel(0x2cf, S5P_APLL_LOCK);

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

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

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

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

	/*
	* 8. Change divider for MFC and G3D
	* (200/4=50)->(200/1=200)Mhz
	*/
	reg = __raw_readl(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);
	__raw_writel(reg, S5P_CLK_DIV2);

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

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

	do {
	reg = __raw_readl(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 need to change memory bus speed, hence onedram clock divier
	* and memory refresh parameter should be changed
	*/
	if (bus_speed_changing) {
	reg = __raw_readl(S5P_CLK_DIV6);
	reg &= ~S5P_CLKDIV6_ONEDRAM_MASK;
	reg \|= (clkdiv_val[index][8] << S5P_CLKDIV6_ONEDRAM_SHIFT);
	__raw_writel(reg, S5P_CLK_DIV6);

	do {
	reg = __raw_readl(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);
	}

	printk(KERN_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 = __raw_readl(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_dmc1;
	}

	/*
	* 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)) {
	printk(KERN_ERR "CPUFreq doesn't support this memory type\n");
	ret = -EINVAL;
	goto out_dmc1;
	}

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

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

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

	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)
	{
	int ret;

	ret = cpufreq_driver_target(cpufreq_cpu_get(0), SLEEP_FREQ, 0);
	if (ret < 0)
	return NOTIFY_BAD;

	no_cpufreq_access = true;
	return NOTIFY_DONE;
	}

	static struct cpufreq_driver s5pv210_driver = {
	.flags = CPUFREQ_STICKY \| 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_node *np;
	int id;

	/*
	* 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.
	*/
	np = of_find_compatible_node(NULL, NULL, "samsung,s5pv210-clock");
	if (!np) {
	pr_err("%s: failed to find clock controller DT node\n",
	__func__);
	return -ENODEV;
	}

	clk_base = of_iomap(np, 0);
	if (!clk_base) {
	pr_err("%s: failed to map clock registers\n", __func__);
	return -EFAULT;
	}

	for_each_compatible_node(np, NULL, "samsung,s5pv210-dmc") {
	id = of_alias_get_id(np, "dmc");
	if (id < 0 \|\| id >= ARRAY_SIZE(dmc_base)) {
	pr_err("%s: failed to get alias of dmc node '%s'\n",
	__func__, np->name);
	return id;
	}

	dmc_base[id] = of_iomap(np, 0);
	if (!dmc_base[id]) {
	pr_err("%s: failed to map dmc%d registers\n",
	__func__, id);
	return -EFAULT;
	}
	}

	for (id = 0; id < ARRAY_SIZE(dmc_base); ++id) {
	if (!dmc_base[id]) {
	pr_err("%s: failed to find dmc%d node\n", __func__, id);
	return -ENODEV;
	}
	}

	arm_regulator = regulator_get(NULL, "vddarm");
	if (IS_ERR(arm_regulator)) {
	pr_err("failed to get regulator vddarm");
	return PTR_ERR(arm_regulator);
	}

	int_regulator = regulator_get(NULL, "vddint");
	if (IS_ERR(int_regulator)) {
	pr_err("failed to get regulator vddint");
	regulator_put(arm_regulator);
	return PTR_ERR(int_regulator);
	}

	register_reboot_notifier(&s5pv210_cpufreq_reboot_notifier);

	return cpufreq_register_driver(&s5pv210_driver);
	}

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