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* OMAP3/OMAP4 Voltage Management Routines
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* Author: Thara Gopinath <thara@ti.com>
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* Copyright (C) 2007 Texas Instruments, Inc.
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* Rajendra Nayak <rnayak@ti.com>
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* Lesly A M <x0080970@ti.com>
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* Copyright (C) 2008, 2011 Nokia Corporation
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* Copyright (C) 2010 Texas Instruments, Inc.
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* Thara Gopinath <thara@ti.com>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/export.h>
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#include <linux/debugfs.h>
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#include <linux/slab.h>
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#include <linux/clk.h>
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#include <plat/common.h>
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#include "prm-regbits-34xx.h"
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#include "prm-regbits-44xx.h"
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#include "prminst44xx.h"
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#include "powerdomain.h"
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static LIST_HEAD(voltdm_list);
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/* Public functions */
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* voltdm_get_voltage() - Gets the current non-auto-compensated voltage
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* @voltdm: pointer to the voltdm for which current voltage info is needed
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* API to get the current non-auto-compensated voltage for a voltage domain.
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* Returns 0 in case of error else returns the current voltage.
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unsigned long voltdm_get_voltage(struct voltagedomain *voltdm)
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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return voltdm->nominal_volt;
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* voltdm_scale() - API to scale voltage of a particular voltage domain.
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* @voltdm: pointer to the voltage domain which is to be scaled.
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* @target_volt: The target voltage of the voltage domain
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* This API should be called by the kernel to do the voltage scaling
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* for a particular voltage domain during DVFS.
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int voltdm_scale(struct voltagedomain *voltdm,
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unsigned long target_volt)
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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pr_err("%s: No voltage scale API registered for vdd_%s\n",
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__func__, voltdm->name);
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ret = voltdm->scale(voltdm, target_volt);
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voltdm->nominal_volt = target_volt;
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* voltdm_reset() - Resets the voltage of a particular voltage domain
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* to that of the current OPP.
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* @voltdm: pointer to the voltage domain whose voltage is to be reset.
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* This API finds out the correct voltage the voltage domain is supposed
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* to be at and resets the voltage to that level. Should be used especially
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* while disabling any voltage compensation modules.
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void voltdm_reset(struct voltagedomain *voltdm)
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unsigned long target_volt;
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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target_volt = voltdm_get_voltage(voltdm);
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pr_err("%s: unable to find current voltage for vdd_%s\n",
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__func__, voltdm->name);
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voltdm_scale(voltdm, target_volt);
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* omap_voltage_get_volttable() - API to get the voltage table associated with a
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* particular voltage domain.
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* @voltdm: pointer to the VDD for which the voltage table is required
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* @volt_data: the voltage table for the particular vdd which is to be
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* populated by this API
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* This API populates the voltage table associated with a VDD into the
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* passed parameter pointer. Returns the count of distinct voltages
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* supported by this vdd.
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void omap_voltage_get_volttable(struct voltagedomain *voltdm,
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struct omap_volt_data **volt_data)
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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*volt_data = voltdm->volt_data;
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* omap_voltage_get_voltdata() - API to get the voltage table entry for a
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* @voltdm: pointer to the VDD whose voltage table has to be searched
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* @volt: the voltage to be searched in the voltage table
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* This API searches through the voltage table for the required voltage
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* domain and tries to find a matching entry for the passed voltage volt.
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* If a matching entry is found volt_data is populated with that entry.
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* This API searches only through the non-compensated voltages int the
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* Returns pointer to the voltage table entry corresponding to volt on
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* success. Returns -ENODATA if no voltage table exisits for the passed voltage
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* domain or if there is no matching entry.
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struct omap_volt_data *omap_voltage_get_voltdata(struct voltagedomain *voltdm,
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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return ERR_PTR(-EINVAL);
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if (!voltdm->volt_data) {
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pr_warning("%s: voltage table does not exist for vdd_%s\n",
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__func__, voltdm->name);
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return ERR_PTR(-ENODATA);
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for (i = 0; voltdm->volt_data[i].volt_nominal != 0; i++) {
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if (voltdm->volt_data[i].volt_nominal == volt)
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return &voltdm->volt_data[i];
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pr_notice("%s: Unable to match the current voltage with the voltage"
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"table for vdd_%s\n", __func__, voltdm->name);
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return ERR_PTR(-ENODATA);
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* omap_voltage_register_pmic() - API to register PMIC specific data
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* @voltdm: pointer to the VDD for which the PMIC specific data is
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* @pmic: the structure containing pmic info
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* This API is to be called by the SOC/PMIC file to specify the
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* pmic specific info as present in omap_voltdm_pmic structure.
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int omap_voltage_register_pmic(struct voltagedomain *voltdm,
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struct omap_voltdm_pmic *pmic)
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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* omap_change_voltscale_method() - API to change the voltage scaling method.
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* @voltdm: pointer to the VDD whose voltage scaling method
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* @voltscale_method: the method to be used for voltage scaling.
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* This API can be used by the board files to change the method of voltage
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* scaling between vpforceupdate and vcbypass. The parameter values are
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* defined in voltage.h
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void omap_change_voltscale_method(struct voltagedomain *voltdm,
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int voltscale_method)
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if (!voltdm || IS_ERR(voltdm)) {
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pr_warning("%s: VDD specified does not exist!\n", __func__);
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switch (voltscale_method) {
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case VOLTSCALE_VPFORCEUPDATE:
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voltdm->scale = omap_vp_forceupdate_scale;
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case VOLTSCALE_VCBYPASS:
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voltdm->scale = omap_vc_bypass_scale;
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pr_warning("%s: Trying to change the method of voltage scaling"
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"to an unsupported one!\n", __func__);
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* omap_voltage_late_init() - Init the various voltage parameters
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* This API is to be called in the later stages of the
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* system boot to init the voltage controller and
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* voltage processors.
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int __init omap_voltage_late_init(void)
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struct voltagedomain *voltdm;
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if (list_empty(&voltdm_list)) {
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pr_err("%s: Voltage driver support not added\n",
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list_for_each_entry(voltdm, &voltdm_list, node) {
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if (!voltdm->scalable)
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sys_ck = clk_get(NULL, voltdm->sys_clk.name);
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if (IS_ERR(sys_ck)) {
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pr_warning("%s: Could not get sys clk.\n", __func__);
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voltdm->sys_clk.rate = clk_get_rate(sys_ck);
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WARN_ON(!voltdm->sys_clk.rate);
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voltdm->scale = omap_vc_bypass_scale;
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omap_vc_init_channel(voltdm);
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voltdm->scale = omap_vp_forceupdate_scale;
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omap_vp_init(voltdm);
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static struct voltagedomain *_voltdm_lookup(const char *name)
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struct voltagedomain *voltdm, *temp_voltdm;
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list_for_each_entry(temp_voltdm, &voltdm_list, node) {
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if (!strcmp(name, temp_voltdm->name)) {
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voltdm = temp_voltdm;
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* voltdm_add_pwrdm - add a powerdomain to a voltagedomain
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* @voltdm: struct voltagedomain * to add the powerdomain to
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* @pwrdm: struct powerdomain * to associate with a voltagedomain
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* Associate the powerdomain @pwrdm with a voltagedomain @voltdm. This
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* enables the use of voltdm_for_each_pwrdm(). Returns -EINVAL if
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* presented with invalid pointers; -ENOMEM if memory could not be allocated;
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int voltdm_add_pwrdm(struct voltagedomain *voltdm, struct powerdomain *pwrdm)
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if (!voltdm || !pwrdm)
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pr_debug("voltagedomain: associating powerdomain %s with voltagedomain "
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"%s\n", pwrdm->name, voltdm->name);
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list_add(&pwrdm->voltdm_node, &voltdm->pwrdm_list);
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* voltdm_for_each_pwrdm - call function for each pwrdm in a voltdm
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* @voltdm: struct voltagedomain * to iterate over
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* @fn: callback function *
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* Call the supplied function @fn for each powerdomain in the
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* voltagedomain @voltdm. Returns -EINVAL if presented with invalid
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* pointers; or passes along the last return value of the callback
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* function, which should be 0 for success or anything else to
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int voltdm_for_each_pwrdm(struct voltagedomain *voltdm,
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int (*fn)(struct voltagedomain *voltdm,
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struct powerdomain *pwrdm))
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struct powerdomain *pwrdm;
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list_for_each_entry(pwrdm, &voltdm->pwrdm_list, voltdm_node)
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ret = (*fn)(voltdm, pwrdm);
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* voltdm_for_each - call function on each registered voltagedomain
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* @fn: callback function *
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* Call the supplied function @fn for each registered voltagedomain.
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* The callback function @fn can return anything but 0 to bail out
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* early from the iterator. Returns the last return value of the
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* callback function, which should be 0 for success or anything else
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* to indicate failure; or -EINVAL if the function pointer is null.
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int voltdm_for_each(int (*fn)(struct voltagedomain *voltdm, void *user),
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struct voltagedomain *temp_voltdm;
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list_for_each_entry(temp_voltdm, &voltdm_list, node) {
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ret = (*fn)(temp_voltdm, user);
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static int _voltdm_register(struct voltagedomain *voltdm)
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if (!voltdm || !voltdm->name)
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INIT_LIST_HEAD(&voltdm->pwrdm_list);
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list_add(&voltdm->node, &voltdm_list);
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pr_debug("voltagedomain: registered %s\n", voltdm->name);
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* voltdm_lookup - look up a voltagedomain by name, return a pointer
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* @name: name of voltagedomain
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* Find a registered voltagedomain by its name @name. Returns a pointer
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* to the struct voltagedomain if found, or NULL otherwise.
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struct voltagedomain *voltdm_lookup(const char *name)
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struct voltagedomain *voltdm ;
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voltdm = _voltdm_lookup(name);
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* voltdm_init - set up the voltagedomain layer
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* @voltdm_list: array of struct voltagedomain pointers to register
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* Loop through the array of voltagedomains @voltdm_list, registering all
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* that are available on the current CPU. If voltdm_list is supplied
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* and not null, all of the referenced voltagedomains will be
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* registered. No return value.
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void voltdm_init(struct voltagedomain **voltdms)
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struct voltagedomain **v;
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for (v = voltdms; *v; v++)
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_voltdm_register(*v);