arch/arm/mach-omap2/vc.c - kernel/panda - Git at Google

 /*
  * OMAP Voltage Controller (VC) interface
  *
  * Copyright (C) 2011 Texas Instruments, Inc.
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/init.h>

 #include <plat/cpu.h>

 #include "voltage.h"
 #include "vc.h"
 #include "prm-regbits-34xx.h"
 #include "prm-regbits-44xx.h"
 #include "prm44xx.h"

 /**
  * struct omap_vc_channel_cfg - describe the cfg_channel bitfield
  * @sa: bit for slave address
  * @rav: bit for voltage configuration register
  * @rac: bit for command configuration register
  * @racen: enable bit for RAC
  * @cmd: bit for command value set selection
  *
  * Channel configuration bits, common for OMAP3+
  * OMAP3 register: PRM_VC_CH_CONF
  * OMAP4 register: PRM_VC_CFG_CHANNEL
  * OMAP5 register: PRM_VC_SMPS_<voltdm>_CONFIG
  */
 struct omap_vc_channel_cfg {
 	u8 sa;
 	u8 rav;
 	u8 rac;
 	u8 racen;
 	u8 cmd;
 };

 static struct omap_vc_channel_cfg vc_default_channel_cfg = {
 	.sa    = BIT(0),
 	.rav   = BIT(1),
 	.rac   = BIT(2),
 	.racen = BIT(3),
 	.cmd   = BIT(4),
 };

 /*
  * On OMAP3+, all VC channels have the above default bitfield
  * configuration, except the OMAP4 MPU channel.  This appears
  * to be a freak accident as every other VC channel has the
  * default configuration, thus creating a mutant channel config.
  */
 static struct omap_vc_channel_cfg vc_mutant_channel_cfg = {
 	.sa    = BIT(0),
 	.rav   = BIT(2),
 	.rac   = BIT(3),
 	.racen = BIT(4),
 	.cmd   = BIT(1),
 };

 static struct omap_vc_channel_cfg *vc_cfg_bits;
 #define CFG_CHANNEL_MASK 0x1f

 /**
  * omap_vc_config_channel - configure VC channel to PMIC mappings
  * @voltdm: pointer to voltagdomain defining the desired VC channel
  *
  * Configures the VC channel to PMIC mappings for the following
  * PMIC settings
  * - i2c slave address (SA)
  * - voltage configuration address (RAV)
  * - command configuration address (RAC) and enable bit (RACEN)
  * - command values for ON, ONLP, RET and OFF (CMD)
  *
  * This function currently only allows flexible configuration of the
  * non-default channel.  Starting with OMAP4, there are more than 2
  * channels, with one defined as the default (on OMAP4, it's MPU.)
  * Only the non-default channel can be configured.
  */
 static int omap_vc_config_channel(struct voltagedomain *voltdm)
 {
 	struct omap_vc_channel *vc = voltdm->vc;

 	/*
 	 * For default channel, the only configurable bit is RACEN.
 	 * All others must stay at zero (see function comment above.)
 	 */
 	if (vc->flags & OMAP_VC_CHANNEL_DEFAULT)
 		vc->cfg_channel &= vc_cfg_bits->racen;

 	voltdm->rmw(CFG_CHANNEL_MASK << vc->cfg_channel_sa_shift,
 		    vc->cfg_channel << vc->cfg_channel_sa_shift,
 		    vc->cfg_channel_reg);

 	return 0;
 }

 /* Voltage scale and accessory APIs */
 int omap_vc_pre_scale(struct voltagedomain *voltdm,
 		      unsigned long target_volt,
 		      u8 *target_vsel, u8 *current_vsel)
 {
 	struct omap_vc_channel *vc = voltdm->vc;
 	u32 vc_cmdval;

 	/* Check if sufficient pmic info is available for this vdd */
 	if (!voltdm->pmic) {
 		pr_err("%s: Insufficient pmic info to scale the vdd_%s\n",
 			__func__, voltdm->name);
 		return -EINVAL;
 	}

 	if (!voltdm->pmic->uv_to_vsel) {
 		pr_err("%s: PMIC function to convert voltage in uV to"
 			"vsel not registered. Hence unable to scale voltage"
 			"for vdd_%s\n", __func__, voltdm->name);
 		return -ENODATA;
 	}

 	if (!voltdm->read || !voltdm->write) {
 		pr_err("%s: No read/write API for accessing vdd_%s regs\n",
 			__func__, voltdm->name);
 		return -EINVAL;
 	}

 	*target_vsel = voltdm->pmic->uv_to_vsel(target_volt);
 	*current_vsel = voltdm->pmic->uv_to_vsel(voltdm->nominal_volt);

 	/* Setting the ON voltage to the new target voltage */
 	vc_cmdval = voltdm->read(vc->cmdval_reg);
 	vc_cmdval &= ~vc->common->cmd_on_mask;
 	vc_cmdval |= (*target_vsel << vc->common->cmd_on_shift);
 	voltdm->write(vc_cmdval, vc->cmdval_reg);

 	omap_vp_update_errorgain(voltdm, target_volt);

 	return 0;
 }

 void omap_vc_post_scale(struct voltagedomain *voltdm,
 			unsigned long target_volt,
 			u8 target_vsel, u8 current_vsel)
 {
 	u32 smps_steps = 0, smps_delay = 0;

 	smps_steps = abs(target_vsel - current_vsel);
 	/* SMPS slew rate / step size. 2us added as buffer. */
 	smps_delay = ((smps_steps * voltdm->pmic->step_size) /
 			voltdm->pmic->slew_rate) + 2;
 	udelay(smps_delay);
 }

 /* vc_bypass_scale - VC bypass method of voltage scaling */
 int omap_vc_bypass_scale(struct voltagedomain *voltdm,
 			 unsigned long target_volt)
 {
 	struct omap_vc_channel *vc = voltdm->vc;
 	u32 loop_cnt = 0, retries_cnt = 0;
 	u32 vc_valid, vc_bypass_val_reg, vc_bypass_value;
 	u8 target_vsel, current_vsel;
 	int ret;

 	ret = omap_vc_pre_scale(voltdm, target_volt, &target_vsel, &current_vsel);
 	if (ret)
 		return ret;

 	vc_valid = vc->common->valid;
 	vc_bypass_val_reg = vc->common->bypass_val_reg;
 	vc_bypass_value = (target_vsel << vc->common->data_shift) |
 		(vc->volt_reg_addr << vc->common->regaddr_shift) |
 		(vc->i2c_slave_addr << vc->common->slaveaddr_shift);

 	voltdm->write(vc_bypass_value, vc_bypass_val_reg);
 	voltdm->write(vc_bypass_value | vc_valid, vc_bypass_val_reg);

 	vc_bypass_value = voltdm->read(vc_bypass_val_reg);
 	/*
 	 * 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 = voltdm->read(vc_bypass_val_reg);
 	}

 	return 0;

 }

 static int omap_vc_bypass_send_value(struct voltagedomain *voltdm,
 		struct omap_vc_channel *vc, u8 sa, u8 reg, u32 data)
 {
 	u32 loop_cnt = 0, retries_cnt = 0;
 	u32 vc_valid, vc_bypass_val_reg, vc_bypass_value;

 	if (IS_ERR_OR_NULL(vc->common)) {
 		pr_err("%s voldm=%s bad value for vc->common\n",
 				__func__, voltdm->name);
 		return -EINVAL;
 	}

 	vc_valid = vc->common->valid;
 	vc_bypass_val_reg = vc->common->bypass_val_reg;
 	vc_bypass_value = (data << vc->common->data_shift) |
 		(reg << vc->common->regaddr_shift) |
 		(sa << vc->common->slaveaddr_shift);

 	voltdm->write(vc_bypass_value, vc_bypass_val_reg);
 	voltdm->write(vc_bypass_value | vc_valid, vc_bypass_val_reg);

 	vc_bypass_value = voltdm->read(vc_bypass_val_reg);

 	/*
 	 * 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 = voltdm->read(vc_bypass_val_reg);
 	}

 	return 0;

 }

 /**
  * omap_vc_bypass_send_i2c_msg() - Function to control PMIC registers over SRI2C
  * @voltdm:	voltage domain
  * @slave_addr:	slave address of the device.
  * @reg_addr:	register address to access
  * @data:	what do we want to write there
  *
  * Many simpler PMICs with a single I2C interface still have configuration
  * registers that may need population. Typical being slew rate configurations
  * thermal shutdown configuration etc. When these PMICs are hooked on I2C_SR,
  * this function allows these configuration registers to be accessed.
  *
  * WARNING: Though this could be used for voltage register configurations over
  * I2C_SR, DONOT use it for that purpose, all the Voltage controller's internal
  * information is bypassed using this function and must be used judiciously.
  */
 int omap_vc_bypass_send_i2c_msg(struct voltagedomain *voltdm, u8 slave_addr,
 				u8 reg_addr, u8 data)
 {
 	struct omap_vc_channel *vc;

 	if (IS_ERR_OR_NULL(voltdm)) {
 		pr_err("%s bad voldm\n", __func__);
 		return -EINVAL;
 	}

 	vc = voltdm->vc;
 	if (IS_ERR_OR_NULL(vc)) {
 		pr_err("%s voldm=%s bad vc\n", __func__, voltdm->name);
 		return -EINVAL;
 	}

 	return omap_vc_bypass_send_value(voltdm, vc, slave_addr,
 					reg_addr, data);
 }

 static void __init omap3_vfsm_init(struct voltagedomain *voltdm)
 {
 	/*
 	 * Voltage Manager FSM parameters init
 	 * XXX This data should be passed in from the board file
 	 */
 	voltdm->write(OMAP3_CLKSETUP, OMAP3_PRM_CLKSETUP_OFFSET);
 	voltdm->write(OMAP3_VOLTOFFSET, OMAP3_PRM_VOLTOFFSET_OFFSET);
 	voltdm->write(OMAP3_VOLTSETUP2, OMAP3_PRM_VOLTSETUP2_OFFSET);
 }

 static void __init omap3_vc_init_channel(struct voltagedomain *voltdm)
 {
 	static bool is_initialized;

 	if (is_initialized)
 		return;

 	omap3_vfsm_init(voltdm);

 	is_initialized = true;
 }


 /* OMAP4 specific voltage init functions */
 static void __init omap4_vc_init_channel(struct voltagedomain *voltdm)
 {
 	static bool is_initialized;
 	struct omap_voltdm_pmic *pmic = voltdm->pmic;
 	u32 vc_val = 0;

 	if (is_initialized)
 		return;

 	if (pmic->i2c_high_speed) {
 		vc_val |= pmic->i2c_hscll_low << OMAP4430_HSCLL_SHIFT;
 		vc_val |= pmic->i2c_hscll_high << OMAP4430_HSCLH_SHIFT;
 	}

 	vc_val |= pmic->i2c_scll_low << OMAP4430_SCLL_SHIFT;
 	vc_val |= pmic->i2c_scll_high << OMAP4430_SCLH_SHIFT;

 	if (vc_val)
 		voltdm->write(vc_val, OMAP4_PRM_VC_CFG_I2C_CLK_OFFSET);

 	is_initialized = true;
 }

 /**
  * omap_vc_i2c_init - initialize I2C interface to PMIC
  * @voltdm: voltage domain containing VC data
  *
  * Use PMIC supplied seetings for I2C high-speed mode and
  * master code (if set) and program the VC I2C configuration
  * register.
  *
  * The VC I2C configuration is common to all VC channels,
  * so this function only configures I2C for the first VC
  * channel registers.  All other VC channels will use the
  * same configuration.
  */
 static void __init omap_vc_i2c_init(struct voltagedomain *voltdm)
 {
 	struct omap_vc_channel *vc = voltdm->vc;
 	static bool initialized;
 	static bool i2c_high_speed;
 	u8 mcode;

 	if (initialized) {
 		if (voltdm->pmic->i2c_high_speed != i2c_high_speed)
 			pr_warn("%s: I2C config for all channels must match.",
 				__func__);
 		return;
 	}

 	i2c_high_speed = voltdm->pmic->i2c_high_speed;
 	if (i2c_high_speed)
 		voltdm->rmw(vc->common->i2c_cfg_hsen_mask,
 			    vc->common->i2c_cfg_hsen_mask,
 			    vc->common->i2c_cfg_reg);

 	mcode = voltdm->pmic->i2c_mcode;
 	if (mcode)
 		voltdm->rmw(vc->common->i2c_mcode_mask,
 			    mcode << __ffs(vc->common->i2c_mcode_mask),
 			    vc->common->i2c_cfg_reg);

 	initialized = true;
 }

 void __init omap_vc_init_channel(struct voltagedomain *voltdm)
 {
 	struct omap_vc_channel *vc = voltdm->vc;
 	u8 on_vsel, onlp_vsel, ret_vsel, off_vsel;
 	u32 val;

 	if (!voltdm->pmic || !voltdm->pmic->uv_to_vsel) {
 		pr_err("%s: PMIC info requried to configure vc for"
 			"vdd_%s not populated.Hence cannot initialize vc\n",
 			__func__, voltdm->name);
 		return;
 	}

 	if (!voltdm->read || !voltdm->write) {
 		pr_err("%s: No read/write API for accessing vdd_%s regs\n",
 			__func__, voltdm->name);
 		return;
 	}

 	vc->cfg_channel = 0;
 	if (vc->flags & OMAP_VC_CHANNEL_CFG_MUTANT)
 		vc_cfg_bits = &vc_mutant_channel_cfg;
 	else
 		vc_cfg_bits = &vc_default_channel_cfg;

 	/* get PMIC/board specific settings */
 	vc->i2c_slave_addr = voltdm->pmic->i2c_slave_addr;
 	vc->volt_reg_addr = voltdm->pmic->volt_reg_addr;
 	vc->cmd_reg_addr = voltdm->pmic->cmd_reg_addr;
 	vc->setup_time = voltdm->pmic->volt_setup_time;

 	/* Configure the i2c slave address for this VC */
 	voltdm->rmw(vc->smps_sa_mask,
 		    vc->i2c_slave_addr << __ffs(vc->smps_sa_mask),
 		    vc->smps_sa_reg);
 	vc->cfg_channel |= vc_cfg_bits->sa;

 	/*
 	 * Configure the PMIC register addresses.
 	 */
 	voltdm->rmw(vc->smps_volra_mask,
 		    vc->volt_reg_addr << __ffs(vc->smps_volra_mask),
 		    vc->smps_volra_reg);
 	vc->cfg_channel |= vc_cfg_bits->rav;

 	if (vc->cmd_reg_addr) {
 		voltdm->rmw(vc->smps_cmdra_mask,
 			    vc->cmd_reg_addr << __ffs(vc->smps_cmdra_mask),
 			    vc->smps_cmdra_reg);
 		vc->cfg_channel |= vc_cfg_bits->rac | vc_cfg_bits->racen;
 	}

 	/* Set up the on, inactive, retention and off voltage */
 	on_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->on_volt);
 	onlp_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->onlp_volt);
 	ret_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->ret_volt);
 	off_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->off_volt);
 	val = ((on_vsel << vc->common->cmd_on_shift) |
 	       (onlp_vsel << vc->common->cmd_onlp_shift) |
 	       (ret_vsel << vc->common->cmd_ret_shift) |
 	       (off_vsel << vc->common->cmd_off_shift));
 	voltdm->write(val, vc->cmdval_reg);
 	vc->cfg_channel |= vc_cfg_bits->cmd;

 	/* Channel configuration */
 	omap_vc_config_channel(voltdm);

 	/* Configure the setup times */
 	voltdm->rmw(voltdm->vfsm->voltsetup_mask,
 		    vc->setup_time << __ffs(voltdm->vfsm->voltsetup_mask),
 		    voltdm->vfsm->voltsetup_reg);

 	omap_vc_i2c_init(voltdm);

 	if (cpu_is_omap34xx())
 		omap3_vc_init_channel(voltdm);
 	else if (cpu_is_omap44xx())
 		omap4_vc_init_channel(voltdm);
 }
	/*
	* OMAP Voltage Controller (VC) interface
	*
	* Copyright (C) 2011 Texas Instruments, Inc.
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/init.h>

	#include <plat/cpu.h>

	#include "voltage.h"
	#include "vc.h"
	#include "prm-regbits-34xx.h"
	#include "prm-regbits-44xx.h"
	#include "prm44xx.h"

	/**
	* struct omap_vc_channel_cfg - describe the cfg_channel bitfield
	* @sa: bit for slave address
	* @rav: bit for voltage configuration register
	* @rac: bit for command configuration register
	* @racen: enable bit for RAC
	* @cmd: bit for command value set selection
	*
	* Channel configuration bits, common for OMAP3+
	* OMAP3 register: PRM_VC_CH_CONF
	* OMAP4 register: PRM_VC_CFG_CHANNEL
	* OMAP5 register: PRM_VC_SMPS_<voltdm>_CONFIG
	*/
	struct omap_vc_channel_cfg {
	u8 sa;
	u8 rav;
	u8 rac;
	u8 racen;
	u8 cmd;
	};

	static struct omap_vc_channel_cfg vc_default_channel_cfg = {
	.sa = BIT(0),
	.rav = BIT(1),
	.rac = BIT(2),
	.racen = BIT(3),
	.cmd = BIT(4),
	};

	/*
	* On OMAP3+, all VC channels have the above default bitfield
	* configuration, except the OMAP4 MPU channel. This appears
	* to be a freak accident as every other VC channel has the
	* default configuration, thus creating a mutant channel config.
	*/
	static struct omap_vc_channel_cfg vc_mutant_channel_cfg = {
	.sa = BIT(0),
	.rav = BIT(2),
	.rac = BIT(3),
	.racen = BIT(4),
	.cmd = BIT(1),
	};

	static struct omap_vc_channel_cfg *vc_cfg_bits;
	#define CFG_CHANNEL_MASK 0x1f

	/**
	* omap_vc_config_channel - configure VC channel to PMIC mappings
	* @voltdm: pointer to voltagdomain defining the desired VC channel
	*
	* Configures the VC channel to PMIC mappings for the following
	* PMIC settings
	* - i2c slave address (SA)
	* - voltage configuration address (RAV)
	* - command configuration address (RAC) and enable bit (RACEN)
	* - command values for ON, ONLP, RET and OFF (CMD)
	*
	* This function currently only allows flexible configuration of the
	* non-default channel. Starting with OMAP4, there are more than 2
	* channels, with one defined as the default (on OMAP4, it's MPU.)
	* Only the non-default channel can be configured.
	*/
	static int omap_vc_config_channel(struct voltagedomain *voltdm)
	{
	struct omap_vc_channel *vc = voltdm->vc;

	/*
	* For default channel, the only configurable bit is RACEN.
	* All others must stay at zero (see function comment above.)
	*/
	if (vc->flags & OMAP_VC_CHANNEL_DEFAULT)
	vc->cfg_channel &= vc_cfg_bits->racen;

	voltdm->rmw(CFG_CHANNEL_MASK << vc->cfg_channel_sa_shift,
	vc->cfg_channel << vc->cfg_channel_sa_shift,
	vc->cfg_channel_reg);

	return 0;
	}

	/* Voltage scale and accessory APIs */
	int omap_vc_pre_scale(struct voltagedomain *voltdm,
	unsigned long target_volt,
	u8 target_vsel, u8 current_vsel)
	{
	struct omap_vc_channel *vc = voltdm->vc;
	u32 vc_cmdval;

	/* Check if sufficient pmic info is available for this vdd */
	if (!voltdm->pmic) {
	pr_err("%s: Insufficient pmic info to scale the vdd_%s\n",
	__func__, voltdm->name);
	return -EINVAL;
	}

	if (!voltdm->pmic->uv_to_vsel) {
	pr_err("%s: PMIC function to convert voltage in uV to"
	"vsel not registered. Hence unable to scale voltage"
	"for vdd_%s\n", __func__, voltdm->name);
	return -ENODATA;
	}

	if (!voltdm->read \|\| !voltdm->write) {
	pr_err("%s: No read/write API for accessing vdd_%s regs\n",
	__func__, voltdm->name);
	return -EINVAL;
	}

	*target_vsel = voltdm->pmic->uv_to_vsel(target_volt);
	*current_vsel = voltdm->pmic->uv_to_vsel(voltdm->nominal_volt);

	/* Setting the ON voltage to the new target voltage */
	vc_cmdval = voltdm->read(vc->cmdval_reg);
	vc_cmdval &= ~vc->common->cmd_on_mask;
	vc_cmdval \|= (*target_vsel << vc->common->cmd_on_shift);
	voltdm->write(vc_cmdval, vc->cmdval_reg);

	omap_vp_update_errorgain(voltdm, target_volt);

	return 0;
	}

	void omap_vc_post_scale(struct voltagedomain *voltdm,
	unsigned long target_volt,
	u8 target_vsel, u8 current_vsel)
	{
	u32 smps_steps = 0, smps_delay = 0;

	smps_steps = abs(target_vsel - current_vsel);
	/* SMPS slew rate / step size. 2us added as buffer. */
	smps_delay = ((smps_steps * voltdm->pmic->step_size) /
	voltdm->pmic->slew_rate) + 2;
	udelay(smps_delay);
	}

	/* vc_bypass_scale - VC bypass method of voltage scaling */
	int omap_vc_bypass_scale(struct voltagedomain *voltdm,
	unsigned long target_volt)
	{
	struct omap_vc_channel *vc = voltdm->vc;
	u32 loop_cnt = 0, retries_cnt = 0;
	u32 vc_valid, vc_bypass_val_reg, vc_bypass_value;
	u8 target_vsel, current_vsel;
	int ret;

	ret = omap_vc_pre_scale(voltdm, target_volt, &target_vsel, &current_vsel);
	if (ret)
	return ret;

	vc_valid = vc->common->valid;
	vc_bypass_val_reg = vc->common->bypass_val_reg;
	vc_bypass_value = (target_vsel << vc->common->data_shift) \|
	(vc->volt_reg_addr << vc->common->regaddr_shift) \|
	(vc->i2c_slave_addr << vc->common->slaveaddr_shift);

	voltdm->write(vc_bypass_value, vc_bypass_val_reg);
	voltdm->write(vc_bypass_value \| vc_valid, vc_bypass_val_reg);

	vc_bypass_value = voltdm->read(vc_bypass_val_reg);
	/*
	* 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 = voltdm->read(vc_bypass_val_reg);
	}

	return 0;

	}

	static int omap_vc_bypass_send_value(struct voltagedomain *voltdm,
	struct omap_vc_channel *vc, u8 sa, u8 reg, u32 data)
	{
	u32 loop_cnt = 0, retries_cnt = 0;
	u32 vc_valid, vc_bypass_val_reg, vc_bypass_value;

	if (IS_ERR_OR_NULL(vc->common)) {
	pr_err("%s voldm=%s bad value for vc->common\n",
	__func__, voltdm->name);
	return -EINVAL;
	}

	vc_valid = vc->common->valid;
	vc_bypass_val_reg = vc->common->bypass_val_reg;
	vc_bypass_value = (data << vc->common->data_shift) \|
	(reg << vc->common->regaddr_shift) \|
	(sa << vc->common->slaveaddr_shift);

	voltdm->write(vc_bypass_value, vc_bypass_val_reg);
	voltdm->write(vc_bypass_value \| vc_valid, vc_bypass_val_reg);

	vc_bypass_value = voltdm->read(vc_bypass_val_reg);

	/*
	* 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 = voltdm->read(vc_bypass_val_reg);
	}

	return 0;

	}

	/**
	* omap_vc_bypass_send_i2c_msg() - Function to control PMIC registers over SRI2C
	* @voltdm: voltage domain
	* @slave_addr: slave address of the device.
	* @reg_addr: register address to access
	* @data: what do we want to write there
	*
	* Many simpler PMICs with a single I2C interface still have configuration
	* registers that may need population. Typical being slew rate configurations
	* thermal shutdown configuration etc. When these PMICs are hooked on I2C_SR,
	* this function allows these configuration registers to be accessed.
	*
	* WARNING: Though this could be used for voltage register configurations over
	* I2C_SR, DONOT use it for that purpose, all the Voltage controller's internal
	* information is bypassed using this function and must be used judiciously.
	*/
	int omap_vc_bypass_send_i2c_msg(struct voltagedomain *voltdm, u8 slave_addr,
	u8 reg_addr, u8 data)
	{
	struct omap_vc_channel *vc;

	if (IS_ERR_OR_NULL(voltdm)) {
	pr_err("%s bad voldm\n", __func__);
	return -EINVAL;
	}

	vc = voltdm->vc;
	if (IS_ERR_OR_NULL(vc)) {
	pr_err("%s voldm=%s bad vc\n", __func__, voltdm->name);
	return -EINVAL;
	}

	return omap_vc_bypass_send_value(voltdm, vc, slave_addr,
	reg_addr, data);
	}

	static void __init omap3_vfsm_init(struct voltagedomain *voltdm)
	{
	/*
	* Voltage Manager FSM parameters init
	* XXX This data should be passed in from the board file
	*/
	voltdm->write(OMAP3_CLKSETUP, OMAP3_PRM_CLKSETUP_OFFSET);
	voltdm->write(OMAP3_VOLTOFFSET, OMAP3_PRM_VOLTOFFSET_OFFSET);
	voltdm->write(OMAP3_VOLTSETUP2, OMAP3_PRM_VOLTSETUP2_OFFSET);
	}

	static void __init omap3_vc_init_channel(struct voltagedomain *voltdm)
	{
	static bool is_initialized;

	if (is_initialized)
	return;

	omap3_vfsm_init(voltdm);

	is_initialized = true;
	}


	/* OMAP4 specific voltage init functions */
	static void __init omap4_vc_init_channel(struct voltagedomain *voltdm)
	{
	static bool is_initialized;
	struct omap_voltdm_pmic *pmic = voltdm->pmic;
	u32 vc_val = 0;

	if (is_initialized)
	return;

	if (pmic->i2c_high_speed) {
	vc_val \|= pmic->i2c_hscll_low << OMAP4430_HSCLL_SHIFT;
	vc_val \|= pmic->i2c_hscll_high << OMAP4430_HSCLH_SHIFT;
	}

	vc_val \|= pmic->i2c_scll_low << OMAP4430_SCLL_SHIFT;
	vc_val \|= pmic->i2c_scll_high << OMAP4430_SCLH_SHIFT;

	if (vc_val)
	voltdm->write(vc_val, OMAP4_PRM_VC_CFG_I2C_CLK_OFFSET);

	is_initialized = true;
	}

	/**
	* omap_vc_i2c_init - initialize I2C interface to PMIC
	* @voltdm: voltage domain containing VC data
	*
	* Use PMIC supplied seetings for I2C high-speed mode and
	* master code (if set) and program the VC I2C configuration
	* register.
	*
	* The VC I2C configuration is common to all VC channels,
	* so this function only configures I2C for the first VC
	* channel registers. All other VC channels will use the
	* same configuration.
	*/
	static void __init omap_vc_i2c_init(struct voltagedomain *voltdm)
	{
	struct omap_vc_channel *vc = voltdm->vc;
	static bool initialized;
	static bool i2c_high_speed;
	u8 mcode;

	if (initialized) {
	if (voltdm->pmic->i2c_high_speed != i2c_high_speed)
	pr_warn("%s: I2C config for all channels must match.",
	__func__);
	return;
	}

	i2c_high_speed = voltdm->pmic->i2c_high_speed;
	if (i2c_high_speed)
	voltdm->rmw(vc->common->i2c_cfg_hsen_mask,
	vc->common->i2c_cfg_hsen_mask,
	vc->common->i2c_cfg_reg);

	mcode = voltdm->pmic->i2c_mcode;
	if (mcode)
	voltdm->rmw(vc->common->i2c_mcode_mask,
	mcode << __ffs(vc->common->i2c_mcode_mask),
	vc->common->i2c_cfg_reg);

	initialized = true;
	}

	void __init omap_vc_init_channel(struct voltagedomain *voltdm)
	{
	struct omap_vc_channel *vc = voltdm->vc;
	u8 on_vsel, onlp_vsel, ret_vsel, off_vsel;
	u32 val;

	if (!voltdm->pmic \|\| !voltdm->pmic->uv_to_vsel) {
	pr_err("%s: PMIC info requried to configure vc for"
	"vdd_%s not populated.Hence cannot initialize vc\n",
	__func__, voltdm->name);
	return;
	}

	if (!voltdm->read \|\| !voltdm->write) {
	pr_err("%s: No read/write API for accessing vdd_%s regs\n",
	__func__, voltdm->name);
	return;
	}

	vc->cfg_channel = 0;
	if (vc->flags & OMAP_VC_CHANNEL_CFG_MUTANT)
	vc_cfg_bits = &vc_mutant_channel_cfg;
	else
	vc_cfg_bits = &vc_default_channel_cfg;

	/* get PMIC/board specific settings */
	vc->i2c_slave_addr = voltdm->pmic->i2c_slave_addr;
	vc->volt_reg_addr = voltdm->pmic->volt_reg_addr;
	vc->cmd_reg_addr = voltdm->pmic->cmd_reg_addr;
	vc->setup_time = voltdm->pmic->volt_setup_time;

	/* Configure the i2c slave address for this VC */
	voltdm->rmw(vc->smps_sa_mask,
	vc->i2c_slave_addr << __ffs(vc->smps_sa_mask),
	vc->smps_sa_reg);
	vc->cfg_channel \|= vc_cfg_bits->sa;

	/*
	* Configure the PMIC register addresses.
	*/
	voltdm->rmw(vc->smps_volra_mask,
	vc->volt_reg_addr << __ffs(vc->smps_volra_mask),
	vc->smps_volra_reg);
	vc->cfg_channel \|= vc_cfg_bits->rav;

	if (vc->cmd_reg_addr) {
	voltdm->rmw(vc->smps_cmdra_mask,
	vc->cmd_reg_addr << __ffs(vc->smps_cmdra_mask),
	vc->smps_cmdra_reg);
	vc->cfg_channel \|= vc_cfg_bits->rac \| vc_cfg_bits->racen;
	}

	/* Set up the on, inactive, retention and off voltage */
	on_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->on_volt);
	onlp_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->onlp_volt);
	ret_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->ret_volt);
	off_vsel = voltdm->pmic->uv_to_vsel(voltdm->pmic->off_volt);
	val = ((on_vsel << vc->common->cmd_on_shift) \|
	(onlp_vsel << vc->common->cmd_onlp_shift) \|
	(ret_vsel << vc->common->cmd_ret_shift) \|
	(off_vsel << vc->common->cmd_off_shift));
	voltdm->write(val, vc->cmdval_reg);
	vc->cfg_channel \|= vc_cfg_bits->cmd;

	/* Channel configuration */
	omap_vc_config_channel(voltdm);

	/* Configure the setup times */
	voltdm->rmw(voltdm->vfsm->voltsetup_mask,
	vc->setup_time << __ffs(voltdm->vfsm->voltsetup_mask),
	voltdm->vfsm->voltsetup_reg);

	omap_vc_i2c_init(voltdm);

	if (cpu_is_omap34xx())
	omap3_vc_init_channel(voltdm);
	else if (cpu_is_omap44xx())
	omap4_vc_init_channel(voltdm);
	}