diff mbox

[v3,02/11] OMAP3: PM: Adding voltage driver support for OMAP3

Message ID 1285166719-19352-3-git-send-email-thara@ti.com (mailing list archive)
State Changes Requested
Delegated to: Kevin Hilman
Headers show

Commit Message

Thara Gopinath Sept. 22, 2010, 2:45 p.m. UTC
None
diff mbox

Patch

diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index a88b75a..4f74f2b 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -52,7 +52,8 @@  obj-$(CONFIG_ARCH_OMAP2)		+= sdrc2xxx.o
 ifeq ($(CONFIG_PM),y)
 obj-$(CONFIG_ARCH_OMAP2)		+= pm24xx.o
 obj-$(CONFIG_ARCH_OMAP2)		+= sleep24xx.o pm_bus.o
-obj-$(CONFIG_ARCH_OMAP3)		+= pm34xx.o sleep34xx.o cpuidle34xx.o pm_bus.o
+obj-$(CONFIG_ARCH_OMAP3)		+= pm34xx.o sleep34xx.o voltage.o \
+					   cpuidle34xx.o pm_bus.o
 obj-$(CONFIG_ARCH_OMAP4)		+= pm44xx.o pm_bus.o
 obj-$(CONFIG_PM_DEBUG)			+= pm-debug.o
 
diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach-omap2/voltage.c
new file mode 100644
index 0000000..49013cb
--- /dev/null
+++ b/arch/arm/mach-omap2/voltage.c
@@ -0,0 +1,1117 @@ 
+/*
+ * OMAP3/OMAP4 Voltage Management Routines
+ *
+ * Author: Thara Gopinath	<thara@ti.com>
+ *
+ * Copyright (C) 2007 Texas Instruments, Inc.
+ * Rajendra Nayak <rnayak@ti.com>
+ * Lesly A M <x0080970@ti.com>
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ * Kalle Jokiniemi
+ *
+ * Copyright (C) 2010 Texas Instruments, Inc.
+ * Thara Gopinath <thara@ti.com>
+ *
+ * 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/delay.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#include <plat/common.h>
+#include <plat/voltage.h>
+
+#include "prm-regbits-34xx.h"
+
+#define VP_IDLE_TIMEOUT		200
+#define VP_TRANXDONE_TIMEOUT	300
+
+/* PRM voltage module */
+static u32 volt_mod;
+
+/* Voltage processor register offsets */
+struct vp_reg_offs {
+	u8 vpconfig;
+	u8 vstepmin;
+	u8 vstepmax;
+	u8 vlimitto;
+	u8 vstatus;
+	u8 voltage;
+};
+
+/* Voltage Processor bit field values, shifts and masks */
+struct vp_reg_val {
+	/* VPx_VPCONFIG */
+	u32 vpconfig_erroroffset;
+	u16 vpconfig_errorgain;
+	u32 vpconfig_errorgain_mask;
+	u8 vpconfig_errorgain_shift;
+	u32 vpconfig_initvoltage_mask;
+	u8 vpconfig_initvoltage_shift;
+	u32 vpconfig_timeouten;
+	u32 vpconfig_initvdd;
+	u32 vpconfig_forceupdate;
+	u32 vpconfig_vpenable;
+	/* VPx_VSTEPMIN */
+	u8 vstepmin_stepmin;
+	u16 vstepmin_smpswaittimemin;
+	u8 vstepmin_stepmin_shift;
+	u8 vstepmin_smpswaittimemin_shift;
+	/* VPx_VSTEPMAX */
+	u8 vstepmax_stepmax;
+	u16 vstepmax_smpswaittimemax;
+	u8 vstepmax_stepmax_shift;
+	u8 vstepmax_smpswaittimemax_shift;
+	/* VPx_VLIMITTO */
+	u16 vlimitto_vddmin;
+	u16 vlimitto_vddmax;
+	u16 vlimitto_timeout;
+	u16 vlimitto_vddmin_shift;
+	u16 vlimitto_vddmax_shift;
+	u16 vlimitto_timeout_shift;
+	/* PRM_IRQSTATUS*/
+	u32 tranxdone_status;
+};
+
+/**
+ * omap_vdd_info - Per Voltage Domain info
+ *
+ * @volt_data		: voltage table having the distinct voltages supported
+ *			  by the domain and other associated per voltage data.
+ * @vp_offs		: structure containing the offsets for various
+ *			  vp registers
+ * @vp_reg		: the register values, shifts, masks for various
+ *			  vp registers
+ * @volt_data_count	: Number of distinct voltages supported by this vdd.
+ * @nominal_volt	: Nominal voltage for this vdd.
+ * @curr_volt		: Current voltage for this vdd;
+ * cmdval_reg		: Voltage controller cmdval register.
+ * @vdd_sr_reg		: The smartreflex register associated with this VDD.
+ */
+struct omap_vdd_info{
+	struct omap_volt_data *volt_data;
+	struct vp_reg_offs vp_offs;
+	struct vp_reg_val vp_reg;
+	struct voltagedomain voltdm;
+	int volt_data_count;
+	u32 nominal_volt;
+	u32 curr_volt;
+	u8 cmdval_reg;
+	u8 vdd_sr_reg;
+};
+
+static struct omap_vdd_info *vdd_info;
+/*
+ * Number of scalable voltage domains.
+ */
+static int nr_scalable_vdd;
+
+/* OMAP3 VDD sturctures */
+static struct omap_vdd_info omap3_vdd_info[] = {
+	{
+		.vp_offs = {
+			.vpconfig = OMAP3_PRM_VP1_CONFIG_OFFSET,
+			.vstepmin = OMAP3_PRM_VP1_VSTEPMIN_OFFSET,
+			.vstepmax = OMAP3_PRM_VP1_VSTEPMAX_OFFSET,
+			.vlimitto = OMAP3_PRM_VP1_VLIMITTO_OFFSET,
+			.vstatus = OMAP3_PRM_VP1_STATUS_OFFSET,
+			.voltage = OMAP3_PRM_VP1_VOLTAGE_OFFSET,
+		},
+		.voltdm = {
+			.name = "mpu",
+		},
+	},
+	{
+		.vp_offs = {
+			.vpconfig = OMAP3_PRM_VP2_CONFIG_OFFSET,
+			.vstepmin = OMAP3_PRM_VP2_VSTEPMIN_OFFSET,
+			.vstepmax = OMAP3_PRM_VP2_VSTEPMAX_OFFSET,
+			.vlimitto = OMAP3_PRM_VP2_VLIMITTO_OFFSET,
+			.vstatus = OMAP3_PRM_VP2_STATUS_OFFSET,
+			.voltage = OMAP3_PRM_VP2_VOLTAGE_OFFSET,
+		},
+		.voltdm = {
+			.name = "core",
+		},
+	},
+};
+
+#define OMAP3_NR_SCALABLE_VDD ARRAY_SIZE(omap3_vdd_info)
+
+/* TODO: OMAP4 register offsets */
+
+/*
+ * Default voltage controller settings.
+ */
+static struct omap_volt_vc_data vc_config = {
+	.clksetup = 0xff,
+	.voltsetup_time1 = 0xfff,
+	.voltsetup_time2 = 0xfff,
+	.voltoffset = 0xff,
+	.voltsetup2 = 0xff,
+	.vdd0_on = 0x30,        /* 1.2v */
+	.vdd0_onlp = 0x20,      /* 1.0v */
+	.vdd0_ret = 0x1e,       /* 0.975v */
+	.vdd0_off = 0x00,       /* 0.6v */
+	.vdd1_on = 0x2c,        /* 1.15v */
+	.vdd1_onlp = 0x20,      /* 1.0v */
+	.vdd1_ret = 0x1e,       /* .975v */
+	.vdd1_off = 0x00,       /* 0.6v */
+};
+
+/*
+ * Default PMIC Data
+ */
+static struct omap_volt_pmic_info volt_pmic_info = {
+	.slew_rate = 4000,
+	.step_size = 12500,
+};
+
+/*
+ * Structures containing OMAP3430/OMAP3630 voltage supported and various
+ * data associated with it per voltage domain basis. Smartreflex Ntarget
+ * values are left as 0 as they have to be populated by smartreflex
+ * driver after reading the efuse.
+ */
+
+/* VDD1 */
+static struct omap_volt_data omap34xx_vdd1_volt_data[] = {
+	{.volt_nominal = 975000, .sr_errminlimit = 0xF4, .vp_errgain = 0x0C},
+	{.volt_nominal = 1075000, .sr_errminlimit = 0xF4, .vp_errgain = 0x0C},
+	{.volt_nominal = 1200000, .sr_errminlimit = 0xF9, .vp_errgain = 0x18},
+	{.volt_nominal = 1270000, .sr_errminlimit = 0xF9, .vp_errgain = 0x18},
+	{.volt_nominal = 1350000, .sr_errminlimit = 0xF9, .vp_errgain = 0x18},
+};
+
+static struct omap_volt_data omap36xx_vdd1_volt_data[] = {
+	{.volt_nominal = 930000, .sr_errminlimit = 0xF4, .vp_errgain = 0x0C},
+	{.volt_nominal = 1100000, .sr_errminlimit = 0xF9, .vp_errgain = 0x16},
+	{.volt_nominal = 1260000, .sr_errminlimit = 0xFA, .vp_errgain = 0x23},
+	{.volt_nominal = 1350000, .sr_errminlimit = 0xFA, .vp_errgain = 0x27},
+};
+
+/* VDD2 */
+static struct omap_volt_data omap34xx_vdd2_volt_data[] = {
+	{.volt_nominal = 975000, .sr_errminlimit = 0xF4, .vp_errgain = 0x0C},
+	{.volt_nominal = 1050000, .sr_errminlimit = 0xF4, .vp_errgain = 0x0C},
+	{.volt_nominal = 1150000, .sr_errminlimit = 0xF9, .vp_errgain = 0x18},
+};
+
+static struct omap_volt_data omap36xx_vdd2_volt_data[] = {
+	{.volt_nominal = 930000, .sr_errminlimit = 0xF4, .vp_errgain = 0x0C},
+	{.volt_nominal = 1137500, .sr_errminlimit = 0xF9, .vp_errgain = 0x16},
+};
+
+
+/* By default VPFORCEUPDATE is the chosen method of voltage scaling */
+static bool voltscale_vpforceupdate = true;
+
+static inline u32 voltage_read_reg(u8 offset)
+{
+	return prm_read_mod_reg(volt_mod, offset);
+}
+
+static inline void voltage_write_reg(u8 offset, u32 value)
+{
+	prm_write_mod_reg(value, volt_mod, offset);
+}
+
+static void vp_latch_vsel(struct omap_vdd_info *vdd)
+{
+	u32 vpconfig;
+	unsigned long uvdc;
+	char vsel;
+
+	uvdc = omap_voltage_get_nom_volt(&vdd->voltdm);
+	if (!uvdc) {
+		pr_warning("%s: unable to find current voltage for vdd_%s\n",
+			__func__, vdd->voltdm.name);
+		return;
+	}
+
+	if (!volt_pmic_info.uv_to_vsel) {
+		pr_warning("%s: PMIC function to convert voltage in uV to"
+			" vsel not registered\n", __func__);
+		return;
+	}
+
+	vsel = volt_pmic_info.uv_to_vsel(uvdc);
+
+	vpconfig = voltage_read_reg(vdd->vp_offs.vpconfig);
+	vpconfig &= ~(vdd->vp_reg.vpconfig_initvoltage_mask |
+			vdd->vp_reg.vpconfig_initvdd);
+	vpconfig |= vsel << vdd->vp_reg.vpconfig_initvoltage_shift;
+
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	/* Trigger initVDD value copy to voltage processor */
+	voltage_write_reg(vdd->vp_offs.vpconfig,
+			(vpconfig | vdd->vp_reg.vpconfig_initvdd));
+
+	/* Clear initVDD copy trigger bit */
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+}
+
+/* OMAP3 specific voltage init functions */
+/*
+ * Intializes the voltage controller registers with the PMIC and board
+ * specific parameters and voltage setup times for OMAP3. If the board
+ * file does not populate the voltage controller parameters through
+ * omap3_pm_init_vc, default values specified in vc_config is used.
+ */
+static void __init omap3_init_voltagecontroller(void)
+{
+	voltage_write_reg(OMAP3_PRM_VC_SMPS_SA_OFFSET,
+			(OMAP3_SRI2C_SLAVE_ADDR <<
+			 OMAP3430_PRM_VC_SMPS_SA_SA1_SHIFT) |
+			(OMAP3_SRI2C_SLAVE_ADDR <<
+			 OMAP3430_PRM_VC_SMPS_SA_SA0_SHIFT));
+	voltage_write_reg(OMAP3_PRM_VC_SMPS_VOL_RA_OFFSET,
+			(OMAP3_VDD2_SR_CONTROL_REG << OMAP3430_VOLRA1_SHIFT) |
+			(OMAP3_VDD1_SR_CONTROL_REG << OMAP3430_VOLRA0_SHIFT));
+	voltage_write_reg(OMAP3_PRM_VC_CMD_VAL_0_OFFSET,
+			(vc_config.vdd0_on << OMAP3430_VC_CMD_ON_SHIFT) |
+			(vc_config.vdd0_onlp << OMAP3430_VC_CMD_ONLP_SHIFT) |
+			(vc_config.vdd0_ret << OMAP3430_VC_CMD_RET_SHIFT) |
+			(vc_config.vdd0_off << OMAP3430_VC_CMD_OFF_SHIFT));
+	voltage_write_reg(OMAP3_PRM_VC_CMD_VAL_1_OFFSET,
+			(vc_config.vdd1_on << OMAP3430_VC_CMD_ON_SHIFT) |
+			(vc_config.vdd1_onlp << OMAP3430_VC_CMD_ONLP_SHIFT) |
+			(vc_config.vdd1_ret << OMAP3430_VC_CMD_RET_SHIFT) |
+			(vc_config.vdd1_off << OMAP3430_VC_CMD_OFF_SHIFT));
+	voltage_write_reg(OMAP3_PRM_VC_CH_CONF_OFFSET,
+			OMAP3430_CMD1_MASK | OMAP3430_RAV1_MASK);
+	voltage_write_reg(OMAP3_PRM_VC_I2C_CFG_OFFSET,
+			OMAP3430_MCODE_SHIFT | OMAP3430_HSEN_MASK);
+
+	/* Write setup times */
+	voltage_write_reg(OMAP3_PRM_CLKSETUP_OFFSET, vc_config.clksetup);
+	voltage_write_reg(OMAP3_PRM_VOLTSETUP1_OFFSET,
+			(vc_config.voltsetup_time2 <<
+			 OMAP3430_SETUP_TIME2_SHIFT) |
+			(vc_config.voltsetup_time1 <<
+			 OMAP3430_SETUP_TIME1_SHIFT));
+	voltage_write_reg(OMAP3_PRM_VOLTOFFSET_OFFSET, vc_config.voltoffset);
+	voltage_write_reg(OMAP3_PRM_VOLTSETUP2_OFFSET, vc_config.voltsetup2);
+}
+
+/* Sets up all the VDD related info for OMAP3 */
+static void __init omap3_vdd_data_configure(struct omap_vdd_info *vdd)
+{
+	struct clk *sys_ck;
+	u32 sys_clk_speed, timeout_val, waittime;
+
+	if (!strcmp(vdd->voltdm.name, "mpu")) {
+		if (cpu_is_omap3630()) {
+			vdd->vp_reg.vlimitto_vddmin =
+					OMAP3630_VP1_VLIMITTO_VDDMIN;
+			vdd->vp_reg.vlimitto_vddmax =
+					OMAP3630_VP1_VLIMITTO_VDDMAX;
+			vdd->volt_data = omap36xx_vdd1_volt_data;
+			vdd->volt_data_count =
+					ARRAY_SIZE(omap36xx_vdd1_volt_data);
+		} else {
+			vdd->vp_reg.vlimitto_vddmin =
+					OMAP3430_VP1_VLIMITTO_VDDMIN;
+			vdd->vp_reg.vlimitto_vddmax =
+					OMAP3430_VP1_VLIMITTO_VDDMAX;
+			vdd->volt_data = omap34xx_vdd1_volt_data;
+			vdd->volt_data_count =
+					ARRAY_SIZE(omap34xx_vdd1_volt_data);
+		}
+
+		vdd->vp_reg.tranxdone_status = OMAP3430_VP1_TRANXDONE_ST_MASK;
+		vdd->cmdval_reg = OMAP3_PRM_VC_CMD_VAL_0_OFFSET;
+		vdd->vdd_sr_reg = OMAP3_VDD1_SR_CONTROL_REG;
+	} else if (!strcmp(vdd->voltdm.name, "core")) {
+		if (cpu_is_omap3630()) {
+			vdd->vp_reg.vlimitto_vddmin =
+					OMAP3630_VP2_VLIMITTO_VDDMIN;
+			vdd->vp_reg.vlimitto_vddmax =
+					OMAP3630_VP2_VLIMITTO_VDDMAX;
+			vdd->volt_data = omap36xx_vdd2_volt_data;
+			vdd->volt_data_count =
+					ARRAY_SIZE(omap36xx_vdd2_volt_data);
+		} else {
+			vdd->vp_reg.vlimitto_vddmin =
+					OMAP3430_VP2_VLIMITTO_VDDMIN;
+			vdd->vp_reg.vlimitto_vddmax =
+					OMAP3430_VP2_VLIMITTO_VDDMAX;
+			vdd->volt_data = omap34xx_vdd2_volt_data;
+			vdd->volt_data_count =
+					ARRAY_SIZE(omap34xx_vdd2_volt_data);
+		}
+
+		vdd->vp_reg.tranxdone_status = OMAP3430_VP2_TRANXDONE_ST_MASK;
+		vdd->cmdval_reg = OMAP3_PRM_VC_CMD_VAL_1_OFFSET;
+		vdd->vdd_sr_reg = OMAP3_VDD2_SR_CONTROL_REG;
+	} else {
+		pr_warning("%s: vdd_%s does not exisit in OMAP3\n",
+			__func__, vdd->voltdm.name);
+		return;
+	}
+
+	/*
+	 * Sys clk rate is require to calculate vp timeout value and
+	 * smpswaittimemin and smpswaittimemax.
+	 */
+	sys_ck = clk_get(NULL, "sys_ck");
+	if (IS_ERR(sys_ck)) {
+		pr_warning("%s: Could not get the sys clk to calculate"
+			"various vdd_%s params\n", __func__, vdd->voltdm.name);
+		return;
+	}
+	sys_clk_speed = clk_get_rate(sys_ck);
+	clk_put(sys_ck);
+	/* Divide to avoid overflow */
+	sys_clk_speed /= 1000;
+
+	/* Nominal/Reset voltage of the VDD */
+	vdd->nominal_volt = vdd->curr_volt = 1200000;
+
+	/* VPCONFIG bit fields */
+	vdd->vp_reg.vpconfig_erroroffset = (OMAP3_VP_CONFIG_ERROROFFSET <<
+				 OMAP3430_ERROROFFSET_SHIFT);
+	vdd->vp_reg.vpconfig_errorgain_mask = OMAP3430_ERRORGAIN_MASK;
+	vdd->vp_reg.vpconfig_errorgain_shift = OMAP3430_ERRORGAIN_SHIFT;
+	vdd->vp_reg.vpconfig_initvoltage_shift = OMAP3430_INITVOLTAGE_SHIFT;
+	vdd->vp_reg.vpconfig_initvoltage_mask = OMAP3430_INITVOLTAGE_MASK;
+	vdd->vp_reg.vpconfig_timeouten = OMAP3430_TIMEOUTEN_MASK;
+	vdd->vp_reg.vpconfig_initvdd = OMAP3430_INITVDD_MASK;
+	vdd->vp_reg.vpconfig_forceupdate = OMAP3430_FORCEUPDATE_MASK;
+	vdd->vp_reg.vpconfig_vpenable = OMAP3430_VPENABLE_MASK;
+
+	/* VSTEPMIN VSTEPMAX bit fields */
+	waittime = ((volt_pmic_info.step_size / volt_pmic_info.slew_rate) *
+				sys_clk_speed) / 1000;
+	vdd->vp_reg.vstepmin_smpswaittimemin = waittime;
+	vdd->vp_reg.vstepmax_smpswaittimemax = waittime;
+	vdd->vp_reg.vstepmin_stepmin = OMAP3_VP_VSTEPMIN_VSTEPMIN;
+	vdd->vp_reg.vstepmax_stepmax = OMAP3_VP_VSTEPMAX_VSTEPMAX;
+	vdd->vp_reg.vstepmin_smpswaittimemin_shift =
+				OMAP3430_SMPSWAITTIMEMIN_SHIFT;
+	vdd->vp_reg.vstepmax_smpswaittimemax_shift =
+				OMAP3430_SMPSWAITTIMEMAX_SHIFT;
+	vdd->vp_reg.vstepmin_stepmin_shift = OMAP3430_VSTEPMIN_SHIFT;
+	vdd->vp_reg.vstepmax_stepmax_shift = OMAP3430_VSTEPMAX_SHIFT;
+
+	/* VLIMITTO bit fields */
+	timeout_val = (sys_clk_speed * OMAP3_VP_VLIMITTO_TIMEOUT_US) / 1000;
+	vdd->vp_reg.vlimitto_timeout = timeout_val;
+	vdd->vp_reg.vlimitto_vddmin_shift = OMAP3430_VDDMIN_SHIFT;
+	vdd->vp_reg.vlimitto_vddmax_shift = OMAP3430_VDDMAX_SHIFT;
+	vdd->vp_reg.vlimitto_timeout_shift = OMAP3430_TIMEOUT_SHIFT;
+}
+
+/* Generic voltage init functions */
+static void __init init_voltageprocessor(struct omap_vdd_info *vdd)
+{
+	u32 vpconfig;
+
+	vpconfig = vdd->vp_reg.vpconfig_erroroffset |
+			(vdd->vp_reg.vpconfig_errorgain <<
+			vdd->vp_reg.vpconfig_errorgain_shift) |
+			vdd->vp_reg.vpconfig_timeouten;
+
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	voltage_write_reg(vdd->vp_offs.vstepmin,
+			(vdd->vp_reg.vstepmin_smpswaittimemin <<
+			vdd->vp_reg.vstepmin_smpswaittimemin_shift) |
+			(vdd->vp_reg.vstepmin_stepmin <<
+			vdd->vp_reg.vstepmin_stepmin_shift));
+
+	voltage_write_reg(vdd->vp_offs.vstepmax,
+			(vdd->vp_reg.vstepmax_smpswaittimemax <<
+			vdd->vp_reg.vstepmax_smpswaittimemax_shift) |
+			(vdd->vp_reg.vstepmax_stepmax <<
+			vdd->vp_reg.vstepmax_stepmax_shift));
+
+	voltage_write_reg(vdd->vp_offs.vlimitto,
+			(vdd->vp_reg.vlimitto_vddmax <<
+			vdd->vp_reg.vlimitto_vddmax_shift) |
+			(vdd->vp_reg.vlimitto_vddmin <<
+			vdd->vp_reg.vlimitto_vddmin_shift) |
+			(vdd->vp_reg.vlimitto_timeout <<
+			vdd->vp_reg.vlimitto_timeout_shift));
+
+	/* Set the init voltage */
+	vp_latch_vsel(vdd);
+
+	vpconfig = voltage_read_reg(vdd->vp_offs.vpconfig);
+	/* Force update of voltage */
+	voltage_write_reg(vdd->vp_offs.vpconfig,
+			(vpconfig | vdd->vp_reg.vpconfig_forceupdate));
+	/* Clear force bit */
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+}
+
+static void __init vdd_data_configure(struct omap_vdd_info *vdd)
+{
+	if (cpu_is_omap34xx())
+		omap3_vdd_data_configure(vdd);
+}
+
+static void __init init_voltagecontroller(void)
+{
+	if (cpu_is_omap34xx())
+		omap3_init_voltagecontroller();
+}
+
+/* vc_bypass_scale_voltage - VC bypass method of voltage scaling */
+static int vc_bypass_scale_voltage(struct omap_vdd_info *vdd,
+		unsigned long target_volt)
+{
+	struct omap_volt_data *volt_data;
+	u32 vc_bypass_value, vc_cmdval, vc_valid, vc_bypass_val_reg_offs;
+	u32 vp_errgain_val, vc_cmd_on_mask;
+	u32 loop_cnt = 0, retries_cnt = 0;
+	u32 smps_steps = 0, smps_delay = 0;
+	u8 vc_data_shift, vc_slaveaddr_shift, vc_regaddr_shift;
+	u8 vc_cmd_on_shift;
+	u8 target_vsel, current_vsel, sr_i2c_slave_addr;
+
+	if (cpu_is_omap34xx()) {
+		vc_cmd_on_shift = OMAP3430_VC_CMD_ON_SHIFT;
+		vc_cmd_on_mask = OMAP3430_VC_CMD_ON_MASK;
+		vc_data_shift = OMAP3430_DATA_SHIFT;
+		vc_slaveaddr_shift = OMAP3430_SLAVEADDR_SHIFT;
+		vc_regaddr_shift = OMAP3430_REGADDR_SHIFT;
+		vc_valid = OMAP3430_VALID_MASK;
+		vc_bypass_val_reg_offs = OMAP3_PRM_VC_BYPASS_VAL_OFFSET;
+		sr_i2c_slave_addr = OMAP3_SRI2C_SLAVE_ADDR;
+	} else {
+		pr_warning("%s: Voltage scaling not yet enabled for"
+			"this chip\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Get volt_data corresponding to target_volt */
+	volt_data = omap_voltage_get_voltdata(&vdd->voltdm, target_volt);
+	if (IS_ERR(volt_data)) {
+		/*
+		 * If a match is not found but the target voltage is
+		 * is the nominal vdd voltage allow scaling
+		 */
+		if (target_volt != vdd->nominal_volt) {
+			pr_warning("%s: Unable to get volt table for vdd_%s"
+				"during voltage scaling. Some really Wrong!",
+				__func__, vdd->voltdm.name);
+			return -ENODATA;
+		}
+		volt_data = NULL;
+	}
+
+	if (!volt_pmic_info.uv_to_vsel) {
+		pr_warning("%s: PMIC function to convert voltage in uV to"
+			"vsel not registered. Hence unable to scale voltage"
+			"for vdd_%s\n", __func__, vdd->voltdm.name);
+		return -ENODATA;
+	}
+
+	target_vsel = volt_pmic_info.uv_to_vsel(target_volt);
+	current_vsel = voltage_read_reg(vdd->vp_offs.voltage);
+	smps_steps = abs(target_vsel - current_vsel);
+
+	/* Setting the ON voltage to the new target voltage */
+	vc_cmdval = voltage_read_reg(vdd->cmdval_reg);
+	vc_cmdval &= ~vc_cmd_on_mask;
+	vc_cmdval |= (target_vsel << vc_cmd_on_shift);
+	voltage_write_reg(vdd->cmdval_reg, vc_cmdval);
+
+	/* Setting vp errorgain based on the voltage */
+	if (volt_data) {
+		vp_errgain_val = voltage_read_reg(vdd->vp_offs.vpconfig);
+		vdd->vp_reg.vpconfig_errorgain = volt_data->vp_errgain;
+		vp_errgain_val &= ~vdd->vp_reg.vpconfig_errorgain_mask;
+		vp_errgain_val |= vdd->vp_reg.vpconfig_errorgain <<
+				vdd->vp_reg.vpconfig_errorgain_shift;
+		voltage_write_reg(vdd->vp_offs.vpconfig, vp_errgain_val);
+	}
+
+	vc_bypass_value = (target_vsel << vc_data_shift) |
+			(vdd->vdd_sr_reg << vc_regaddr_shift) |
+			(sr_i2c_slave_addr << vc_slaveaddr_shift);
+
+	voltage_write_reg(vc_bypass_val_reg_offs, vc_bypass_value);
+
+	voltage_write_reg(vc_bypass_val_reg_offs, vc_bypass_value | vc_valid);
+	vc_bypass_value = voltage_read_reg(vc_bypass_val_reg_offs);
+
+	/*
+	 * Loop till the bypass command is acknowledged from the SMPS.
+	 * NOTE: This is legacy code. The loop count and retry count needs
+	 * to be revisited.
+	 */
+	while (!(vc_bypass_value & vc_valid)) {
+		loop_cnt++;
+
+		if (retries_cnt > 10) {
+			pr_warning("%s: Retry count exceeded\n", __func__);
+			return -ETIMEDOUT;
+		}
+
+		if (loop_cnt > 50) {
+			retries_cnt++;
+			loop_cnt = 0;
+			udelay(10);
+		}
+		vc_bypass_value = voltage_read_reg(vc_bypass_val_reg_offs);
+	}
+
+	/* SMPS slew rate / step size. 2us added as buffer. */
+	smps_delay = ((smps_steps * volt_pmic_info.step_size) /
+			volt_pmic_info.slew_rate) + 2;
+	udelay(smps_delay);
+
+	vdd->curr_volt = target_volt;
+
+	return 0;
+}
+
+/* VP force update method of voltage scaling */
+static int vp_forceupdate_scale_voltage(struct omap_vdd_info *vdd,
+		unsigned long target_volt)
+{
+	struct omap_volt_data *volt_data;
+	u32 vc_cmd_on_mask, vc_cmdval, vpconfig;
+	u32 smps_steps = 0, smps_delay = 0;
+	int timeout = 0;
+	u8 target_vsel, current_vsel;
+	u8 vc_cmd_on_shift;
+	u8 prm_irqst_reg_offs, ocp_mod;
+
+	if (cpu_is_omap34xx()) {
+		vc_cmd_on_shift = OMAP3430_VC_CMD_ON_SHIFT;
+		vc_cmd_on_mask = OMAP3430_VC_CMD_ON_MASK;
+		prm_irqst_reg_offs = OMAP3_PRM_IRQSTATUS_MPU_OFFSET;
+		ocp_mod = OCP_MOD;
+	} else {
+		pr_warning("%s: Voltage scaling not yet enabled for"
+			"this chip\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Get volt_data corresponding to the target_volt */
+	volt_data = omap_voltage_get_voltdata(&vdd->voltdm, target_volt);
+	if (IS_ERR(volt_data)) {
+		/*
+		 * If a match is not found but the target voltage is
+		 * is the nominal vdd voltage allow scaling
+		 */
+		if (target_volt != vdd->nominal_volt) {
+			pr_warning("%s: Unable to get voltage table for vdd_%s"
+				"during voltage scaling. Some really Wrong!",
+				__func__, vdd->voltdm.name);
+			return -ENODATA;
+		}
+		volt_data = NULL;
+	}
+
+	if (!volt_pmic_info.uv_to_vsel) {
+		pr_warning("%s: PMIC function to convert voltage in uV to"
+			"vsel not registered. Hence unable to scale voltage"
+			"for vdd_%s\n", __func__, vdd->voltdm.name);
+		return -ENODATA;
+	}
+
+	target_vsel = volt_pmic_info.uv_to_vsel(target_volt);
+	current_vsel = voltage_read_reg(vdd->vp_offs.voltage);
+	smps_steps = abs(target_vsel - current_vsel);
+
+	/* Setting the ON voltage to the new target voltage */
+	vc_cmdval = voltage_read_reg(vdd->cmdval_reg);
+	vc_cmdval &= ~vc_cmd_on_mask;
+	vc_cmdval |= (target_vsel << vc_cmd_on_shift);
+	voltage_write_reg(vdd->cmdval_reg, vc_cmdval);
+
+	/* Getting  vp errorgain based on the voltage */
+	if (volt_data)
+		vdd->vp_reg.vpconfig_errorgain =
+					volt_data->vp_errgain;
+
+	/*
+	 * Clear all pending TransactionDone interrupt/status. Typical latency
+	 * is <3us
+	 */
+	while (timeout++ < VP_TRANXDONE_TIMEOUT) {
+		prm_write_mod_reg(vdd->vp_reg.tranxdone_status,
+				ocp_mod, prm_irqst_reg_offs);
+		if (!(prm_read_mod_reg(ocp_mod, prm_irqst_reg_offs) &
+				vdd->vp_reg.tranxdone_status))
+				break;
+		udelay(1);
+	}
+	if (timeout >= VP_TRANXDONE_TIMEOUT) {
+		pr_warning("%s: vdd_%s TRANXDONE timeout exceeded."
+			"Voltage change aborted", __func__, vdd->voltdm.name);
+		return -ETIMEDOUT;
+	}
+
+	/* Configure for VP-Force Update */
+	vpconfig = voltage_read_reg(vdd->vp_offs.vpconfig);
+	vpconfig &= ~(vdd->vp_reg.vpconfig_initvdd |
+			vdd->vp_reg.vpconfig_forceupdate |
+			vdd->vp_reg.vpconfig_initvoltage_mask |
+			vdd->vp_reg.vpconfig_errorgain_mask);
+	vpconfig |= ((target_vsel <<
+			vdd->vp_reg.vpconfig_initvoltage_shift) |
+			(vdd->vp_reg.vpconfig_errorgain <<
+			 vdd->vp_reg.vpconfig_errorgain_shift));
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	/* Trigger initVDD value copy to voltage processor */
+	vpconfig |= vdd->vp_reg.vpconfig_initvdd;
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	/* Force update of voltage */
+	vpconfig |= vdd->vp_reg.vpconfig_forceupdate;
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	/*
+	 * Wait for TransactionDone. Typical latency is <200us.
+	 * Depends on SMPSWAITTIMEMIN/MAX and voltage change
+	 */
+	timeout = 0;
+	omap_test_timeout((prm_read_mod_reg(ocp_mod, prm_irqst_reg_offs) &
+			vdd->vp_reg.tranxdone_status),
+			VP_TRANXDONE_TIMEOUT, timeout);
+	if (timeout >= VP_TRANXDONE_TIMEOUT)
+		pr_err("%s: vdd_%s TRANXDONE timeout exceeded."
+			"TRANXDONE never got set after the voltage update\n",
+			__func__, vdd->voltdm.name);
+
+	/*
+	 * Wait for voltage to settle with SW wait-loop.
+	 * SMPS slew rate / step size. 2us added as buffer.
+	 */
+	smps_delay = ((smps_steps * volt_pmic_info.step_size) /
+			volt_pmic_info.slew_rate) + 2;
+	udelay(smps_delay);
+
+	/*
+	 * Disable TransactionDone interrupt , clear all status, clear
+	 * control registers
+	 */
+	timeout = 0;
+	while (timeout++ < VP_TRANXDONE_TIMEOUT) {
+		prm_write_mod_reg(vdd->vp_reg.tranxdone_status,
+				ocp_mod, prm_irqst_reg_offs);
+		if (!(prm_read_mod_reg(ocp_mod, prm_irqst_reg_offs) &
+				vdd->vp_reg.tranxdone_status))
+				break;
+		udelay(1);
+	}
+	if (timeout >= VP_TRANXDONE_TIMEOUT)
+		pr_warning("%s: vdd_%s TRANXDONE timeout exceeded while trying"
+			"to clear the TRANXDONE status\n",
+			__func__, vdd->voltdm.name);
+
+	vpconfig = voltage_read_reg(vdd->vp_offs.vpconfig);
+	/* Clear initVDD copy trigger bit */
+	vpconfig &= ~vdd->vp_reg.vpconfig_initvdd;;
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+	/* Clear force bit */
+	vpconfig &= ~vdd->vp_reg.vpconfig_forceupdate;
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	vdd->curr_volt = target_volt;
+
+	return 0;
+}
+
+/* Public functions */
+/**
+ * omap_voltage_get_nom_volt() - Gets the current non-auto-compensated voltage
+ * @voltdm:	pointer to the VDD for which current voltage info is needed
+ *
+ * API to get the current non-auto-compensated voltage for a VDD.
+ * Returns 0 in case of error else returns the current voltage for the VDD.
+ */
+unsigned long omap_voltage_get_nom_volt(struct voltagedomain *voltdm)
+{
+	struct omap_vdd_info *vdd;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return 0;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	return vdd->curr_volt;
+}
+
+/**
+ * omap_vp_get_curr_volt() - API to get the current vp voltage.
+ * @voltdm:	pointer to the VDD.
+ *
+ * This API returns the current voltage for the specified voltage processor
+ */
+unsigned long omap_vp_get_curr_volt(struct voltagedomain *voltdm)
+{
+	struct omap_vdd_info *vdd;
+	u8 curr_vsel;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return 0;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	curr_vsel = voltage_read_reg(vdd->vp_offs.voltage);
+
+	if (!volt_pmic_info.vsel_to_uv) {
+		pr_warning("%s: PMIC function to convert vsel to voltage"
+			"in uV not registerd\n", __func__);
+		return 0;
+	}
+
+	return volt_pmic_info.vsel_to_uv(curr_vsel);
+}
+
+/**
+ * omap_vp_enable() - API to enable a particular VP
+ * @voltdm:	pointer to the VDD whose VP is to be enabled.
+ *
+ * This API enables a particular voltage processor. Needed by the smartreflex
+ * class drivers.
+ */
+void omap_vp_enable(struct voltagedomain *voltdm)
+{
+	struct omap_vdd_info *vdd;
+	u32 vpconfig;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	/* If VP is already enabled, do nothing. Return */
+	if (voltage_read_reg(vdd->vp_offs.vpconfig) &
+				vdd->vp_reg.vpconfig_vpenable)
+		return;
+	/*
+	 * This latching is required only if VC bypass method is used for
+	 * voltage scaling during dvfs.
+	 */
+	if (!voltscale_vpforceupdate)
+		vp_latch_vsel(vdd);
+
+	/* Enable VP */
+	vpconfig = voltage_read_reg(vdd->vp_offs.vpconfig);
+	voltage_write_reg(vdd->vp_offs.vpconfig,
+				vpconfig | vdd->vp_reg.vpconfig_vpenable);
+}
+
+/**
+ * omap_vp_disable() - API to disable a particular VP
+ * @voltdm:	pointer to the VDD whose VP is to be disabled.
+ *
+ * This API disables a particular voltage processor. Needed by the smartreflex
+ * class drivers.
+ */
+void omap_vp_disable(struct voltagedomain *voltdm)
+{
+	struct omap_vdd_info *vdd;
+	u32 vpconfig;
+	int timeout;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	/* If VP is already disabled, do nothing. Return */
+	if (!(voltage_read_reg(vdd->vp_offs.vpconfig) &
+				vdd->vp_reg.vpconfig_vpenable)) {
+		pr_warning("%s: Trying to disable VP for vdd_%s when"
+			"it is already disabled\n", __func__, voltdm->name);
+		return;
+	}
+
+	/* Disable VP */
+	vpconfig = voltage_read_reg(vdd->vp_offs.vpconfig);
+	vpconfig &= ~vdd->vp_reg.vpconfig_vpenable;
+	voltage_write_reg(vdd->vp_offs.vpconfig, vpconfig);
+
+	/*
+	 * Wait for VP idle Typical latency is <2us. Maximum latency is ~100us
+	 */
+	omap_test_timeout((voltage_read_reg(vdd->vp_offs.vstatus)),
+				VP_IDLE_TIMEOUT, timeout);
+
+	if (timeout >= VP_IDLE_TIMEOUT)
+		pr_warning("%s: vdd_%s idle timedout\n",
+			__func__, voltdm->name);
+	return;
+}
+
+/**
+ * omap_voltage_scale_vdd() - API to scale voltage of a particular
+ *				voltage domain.
+ * @voltdm:	pointer to the VDD which is to be scaled.
+ * @target_volt:	The target voltage of the voltage domain
+ *
+ * This API should be called by the kernel to do the voltage scaling
+ * for a particular voltage domain during dvfs or any other situation.
+ */
+int omap_voltage_scale_vdd(struct voltagedomain *voltdm,
+		unsigned long target_volt)
+{
+	struct omap_vdd_info *vdd;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return -EINVAL;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	if (voltscale_vpforceupdate)
+		return vp_forceupdate_scale_voltage(vdd, target_volt);
+	else
+		return vc_bypass_scale_voltage(vdd, target_volt);
+}
+
+
+
+/**
+ * omap_voltage_reset() - Resets the voltage of a particular voltage domain
+ *			to that of the current OPP.
+ * @voltdm:	pointer to the VDD whose voltage is to be reset.
+ *
+ * This API finds out the correct voltage the voltage domain is supposed
+ * to be at and resets the voltage to that level. Should be used expecially
+ * while disabling any voltage compensation modules.
+ */
+void omap_voltage_reset(struct voltagedomain *voltdm)
+{
+	unsigned long target_uvdc;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return;
+	}
+
+	target_uvdc = omap_voltage_get_nom_volt(voltdm);
+	if (!target_uvdc) {
+		pr_err("%s: unable to find current voltage for vdd_%s\n",
+			__func__, voltdm->name);
+		return;
+	}
+
+	omap_voltage_scale_vdd(voltdm, target_uvdc);
+}
+
+/**
+ * omap_change_voltscale_method() - API to change the voltage scaling method.
+ * @voltscale_method:	the method to be used for voltage scaling.
+ *
+ * This API can be used by the board files to change the method of voltage
+ * scaling between vpforceupdate and vcbypass. The parameter values are
+ * defined in voltage.h
+ */
+void omap_change_voltscale_method(int voltscale_method)
+{
+	switch (voltscale_method) {
+	case VOLTSCALE_VPFORCEUPDATE:
+		voltscale_vpforceupdate = true;
+		return;
+	case VOLTSCALE_VCBYPASS:
+		voltscale_vpforceupdate = false;
+		return;
+	default:
+		pr_warning("%s: Trying to change the method of voltage scaling"
+			"to an unsupported one!\n", __func__);
+	}
+}
+
+/**
+ * omap_voltage_init_vc() - polpulates vc_config with values specified in
+ *			  board file
+ * @setup_vc:	the structure with various vc parameters
+ *
+ * Updates vc_config with the voltage setup times and other parameters as
+ * specified in setup_vc. vc_config is later used in init_voltagecontroller
+ * to initialize the voltage controller registers. Board files should call
+ * this function with the correct volatge settings corresponding
+ * the particular PMIC and chip.
+ */
+void __init omap_voltage_init_vc(struct omap_volt_vc_data *setup_vc)
+{
+	if (!setup_vc)
+		return;
+
+	vc_config.clksetup = setup_vc->clksetup;
+	vc_config.voltsetup_time1 = setup_vc->voltsetup_time1;
+	vc_config.voltsetup_time2 = setup_vc->voltsetup_time2;
+	vc_config.voltoffset = setup_vc->voltoffset;
+	vc_config.voltsetup2 = setup_vc->voltsetup2;
+	vc_config.vdd0_on = setup_vc->vdd0_on;
+	vc_config.vdd0_onlp = setup_vc->vdd0_onlp;
+	vc_config.vdd0_ret = setup_vc->vdd0_ret;
+	vc_config.vdd0_off = setup_vc->vdd0_off;
+	vc_config.vdd1_on = setup_vc->vdd1_on;
+	vc_config.vdd1_onlp = setup_vc->vdd1_onlp;
+	vc_config.vdd1_ret = setup_vc->vdd1_ret;
+	vc_config.vdd1_off = setup_vc->vdd1_off;
+}
+
+/**
+ * omap_voltage_get_volttable() - API to get the voltage table associated with a
+ *				particular voltage domain.
+ * @voltdm:	pointer to the VDD for which the voltage table is required
+ * @volt_data:	the voltage table for the particular vdd which is to be
+ *		populated by this API
+ *
+ * This API populates the voltage table associated with a VDD into the
+ * passed parameter pointer. Returns the count of distinct voltages
+ * supported by this vdd.
+ *
+ */
+int omap_voltage_get_volttable(struct voltagedomain *voltdm,
+		struct omap_volt_data **volt_data)
+{
+	struct omap_vdd_info *vdd;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return 0;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	*volt_data = vdd->volt_data;
+	return vdd->volt_data_count;
+}
+
+/**
+ * omap_voltage_get_voltdata() - API to get the voltage table entry for a
+ *				particular voltage
+ * @voltdm:	pointer to the VDD whose voltage table has to be searched
+ * @volt:	the voltage to be searched in the voltage table
+ *
+ * This API searches through the voltage table for the required voltage
+ * domain and tries to find a matching entry for the passed voltage volt.
+ * If a matching entry is found volt_data is populated with that entry.
+ * This API searches only through the non-compensated voltages int the
+ * voltage table.
+ * Returns pointer to the voltage table entry corresponding to volt on
+ * sucess. Returns -ENODATA if no voltage table exisits for the passed voltage
+ * domain or if there is no matching entry.
+ */
+struct omap_volt_data *omap_voltage_get_voltdata(struct voltagedomain *voltdm,
+		unsigned long volt)
+{
+	struct omap_vdd_info *vdd;
+	int i;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	if (!vdd->volt_data) {
+		pr_warning("%s: voltage table does not exist for vdd_%s\n",
+			__func__, voltdm->name);
+		return ERR_PTR(-ENODATA);
+	}
+
+	for (i = 0; i < vdd->volt_data_count; i++) {
+		if (vdd->volt_data[i].volt_nominal == volt)
+			return &vdd->volt_data[i];
+	}
+
+	pr_notice("%s: Unable to match the current voltage with the voltage"
+		"table for vdd_%s\n", __func__, voltdm->name);
+
+	return ERR_PTR(-ENODATA);
+}
+
+/**
+ * omap_voltage_register_pmic() - API to register PMIC specific data
+ * @pmic_info:	the structure containing pmic info
+ *
+ * This API is to be called by the borad file to specify the pmic specific
+ * info as present in omap_volt_pmic_info structure. A default pmic info
+ * table is maintained in the driver volt_pmic_info. If the board file do
+ * not override the default table using this API, the default values wiil
+ * be used in the driver.
+ */
+void omap_voltage_register_pmic(struct omap_volt_pmic_info *pmic_info)
+{
+	volt_pmic_info.slew_rate = pmic_info->slew_rate;
+	volt_pmic_info.step_size = pmic_info->step_size;
+	volt_pmic_info.vsel_to_uv = pmic_info->vsel_to_uv;
+	volt_pmic_info.uv_to_vsel = pmic_info->uv_to_vsel;
+}
+
+/**
+ * omap_voltage_domain_get() - API to get the voltage domain pointer
+ * @name:	Name of the voltage domain
+ *
+ * This API looks up in the global vdd_info struct for the
+ * existence of voltage domain <name>. If it exists, the API returns
+ * a pointer to the voltage domain structure corresponding to the
+ * VDD<name>. Else retuns error pointer.
+ */
+struct voltagedomain *omap_voltage_domain_get(char *name)
+{
+	int i;
+
+	if (!vdd_info) {
+		pr_err("%s: Voltage driver init not yet happened.Faulting!\n",
+			__func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!name) {
+		pr_err("%s: No name to get the votage domain!\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	for (i = 0; i < nr_scalable_vdd; i++) {
+		if (!(strcmp(name, vdd_info[i].voltdm.name)))
+			return &vdd_info[i].voltdm;
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+/**
+ * omap_voltage_init : Volatage init API which does VP and VC init.
+ */
+static int __init omap_voltage_init(void)
+{
+	int i;
+
+	if (cpu_is_omap34xx()) {
+		volt_mod = OMAP3430_GR_MOD;
+		vdd_info = omap3_vdd_info;
+		nr_scalable_vdd = OMAP3_NR_SCALABLE_VDD;
+	} else {
+		pr_warning("%s: voltage driver support not added\n", __func__);
+		return 0;
+	}
+
+	init_voltagecontroller();
+	for (i = 0; i < nr_scalable_vdd; i++) {
+		vdd_data_configure(&vdd_info[i]);
+		init_voltageprocessor(&vdd_info[i]);
+	}
+	return 0;
+}
+core_initcall(omap_voltage_init);
diff --git a/arch/arm/plat-omap/include/plat/voltage.h b/arch/arm/plat-omap/include/plat/voltage.h
new file mode 100644
index 0000000..99836a1
--- /dev/null
+++ b/arch/arm/plat-omap/include/plat/voltage.h
@@ -0,0 +1,136 @@ 
+/*
+ * OMAP Voltage Management Routines
+ *
+ * Author: Thara Gopinath	<thara@ti.com>
+ *
+ * Copyright (C) 2009 Texas Instruments, Inc.
+ * Thara Gopinath <thara@ti.com>
+ *
+ * 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.
+ */
+
+#ifndef __ARCH_ARM_MACH_OMAP2_VOLTAGE_H
+#define __ARCH_ARM_MACH_OMAP2_VOLTAGE_H
+
+#define VOLTSCALE_VPFORCEUPDATE		1
+#define VOLTSCALE_VCBYPASS		2
+
+/* Voltage SR Parameters for OMAP3*/
+#define OMAP3_SRI2C_SLAVE_ADDR			0x12
+#define OMAP3_VDD1_SR_CONTROL_REG		0x00
+#define OMAP3_VDD2_SR_CONTROL_REG		0x01
+
+/*
+ * Omap3 VP register specific values. Maybe these need to come from
+ * board file or PMIC data structure
+ */
+#define OMAP3_VP_CONFIG_ERROROFFSET		0x00
+#define	OMAP3_VP_VSTEPMIN_SMPSWAITTIMEMIN	0x3C
+#define OMAP3_VP_VSTEPMIN_VSTEPMIN		0x1
+#define OMAP3_VP_VSTEPMAX_SMPSWAITTIMEMAX	0x3C
+#define OMAP3_VP_VSTEPMAX_VSTEPMAX		0x04
+#define OMAP3_VP_VLIMITTO_TIMEOUT_US		0x200
+
+/*
+ * Omap3430 specific VP register values. Maybe these need to come from
+ * board file or PMIC data structure
+ */
+#define OMAP3430_VP1_VLIMITTO_VDDMIN		0x14
+#define OMAP3430_VP1_VLIMITTO_VDDMAX		0x42
+#define OMAP3430_VP2_VLIMITTO_VDDMAX		0x2C
+#define OMAP3430_VP2_VLIMITTO_VDDMIN		0x18
+
+/*
+ * Omap3630 specific VP register values. Maybe these need to come from
+ * board file or PMIC data structure
+ */
+#define OMAP3630_VP1_VLIMITTO_VDDMIN		0x18
+#define OMAP3630_VP1_VLIMITTO_VDDMAX		0x3C
+#define OMAP3630_VP2_VLIMITTO_VDDMIN		0x18
+#define OMAP3630_VP2_VLIMITTO_VDDMAX		0x30
+
+/* TODO OMAP4 VP register values if the same file is used for OMAP4*/
+
+/**
+ * voltagedomain - omap voltage domain global structure
+ * @name       : Name of the voltage domain which can be used as a unique
+ *               identifier.
+ */
+struct voltagedomain {
+	char *name;
+};
+
+/**
+ * omap_volt_data - Omap voltage specific data.
+ * @voltage_nominal	: The possible voltage value in uV
+ * @sr_nvalue		: Smartreflex N target value at voltage <voltage>
+ * @sr_errminlimit	: Error min limit value for smartreflex. This value
+ *			  differs at differnet opp and thus is linked
+ *			  with voltage.
+ * @vp_errorgain	: Error gain value for the voltage processor. This
+ *			  field also differs according to the voltage/opp.
+ */
+struct omap_volt_data {
+	u32	volt_nominal;
+	u32	sr_nvalue;
+	u8	sr_errminlimit;
+	u8	vp_errgain;
+};
+
+/**
+ * omap_volt_pmic_info - PMIC specific data required by the voltage driver.
+ * @slew_rate	: PMIC slew rate (in uv/us)
+ * @step_size	: PMIC voltage step size (in uv)
+ * @vsel_to_uv	: PMIC API to convert vsel value to actual voltage in uV.
+ * @uv_to_vsel	: PMIC API to convert voltage in uV to vsel value.
+ */
+struct omap_volt_pmic_info {
+	int slew_rate;
+	int step_size;
+	unsigned long (*vsel_to_uv) (const u8 vsel);
+	u8 (*uv_to_vsel) (unsigned long uV);
+};
+
+/* Various voltage controller related info */
+struct omap_volt_vc_data {
+	u16 clksetup;
+	u16 voltsetup_time1;
+	u16 voltsetup_time2;
+	u16 voltoffset;
+	u16 voltsetup2;
+	/* PRM_VC_CMD_VAL_0 specific bits */
+	u16 vdd0_on;
+	u16 vdd0_onlp;
+	u16 vdd0_ret;
+	u16 vdd0_off;
+	/* PRM_VC_CMD_VAL_1 specific bits */
+	u16 vdd1_on;
+	u16 vdd1_onlp;
+	u16 vdd1_ret;
+	u16 vdd1_off;
+};
+
+struct voltagedomain *omap_voltage_domain_get(char *name);
+unsigned long omap_vp_get_curr_volt(struct voltagedomain *voltdm);
+void omap_vp_enable(struct voltagedomain *voltdm);
+void omap_vp_disable(struct voltagedomain *voltdm);
+int omap_voltage_scale_vdd(struct voltagedomain *voltdm,
+		unsigned long target_volt);
+void omap_voltage_reset(struct voltagedomain *voltdm);
+int omap_voltage_get_volttable(struct voltagedomain *voltdm,
+		struct omap_volt_data **volt_data);
+struct omap_volt_data *omap_voltage_get_voltdata(struct voltagedomain *voltdm,
+		unsigned long volt);
+void omap_voltage_register_pmic(struct omap_volt_pmic_info *pmic_info);
+unsigned long omap_voltage_get_nom_volt(struct voltagedomain *voltdm);
+#ifdef CONFIG_PM
+void omap_voltage_init_vc(struct omap_volt_vc_data *setup_vc);
+void omap_change_voltscale_method(int voltscale_method);
+#else
+static inline void omap_voltage_init_vc(struct omap_volt_vc_data *setup_vc) {}
+static inline  void omap_change_voltscale_method(int voltscale_method) {}
+#endif
+
+#endif