/*
 * OMAP SmartReflex Voltage Control
 *
 * Author: Thara Gopinath       <thara@ti.com>
 *
 * Copyright (C) 2012 Texas Instruments, Inc.
 * Thara Gopinath <thara@ti.com>
 *
 * Copyright (C) 2008 Nokia Corporation
 * Kalle Jokiniemi
 *
 * Copyright (C) 2007 Texas Instruments, Inc.
 * Lesly A M <x0080970@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/module.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/power/smartreflex.h>

#define SMARTREFLEX_NAME_LEN    16
#define NVALUE_NAME_LEN         40
#define SR_DISABLE_TIMEOUT      200

/* sr_list contains all the instances of smartreflex module */
static LIST_HEAD(sr_list);

static struct omap_sr_class_data *sr_class;
static struct omap_sr_pmic_data *sr_pmic_data;
static struct dentry            *sr_dbg_dir;

static inline void sr_write_reg(struct omap_sr *sr, unsigned offset, u32 value)
{
        __raw_writel(value, (sr->base + offset));
}

static inline void sr_modify_reg(struct omap_sr *sr, unsigned offset, u32 mask,
                                        u32 value)
{
        u32 reg_val;

        /*
         * Smartreflex error config register is special as it contains
         * certain status bits which if written a 1 into means a clear
         * of those bits. So in order to make sure no accidental write of
         * 1 happens to those status bits, do a clear of them in the read
         * value. This mean this API doesn't rewrite values in these bits
         * if they are currently set, but does allow the caller to write
         * those bits.
         */
        if (sr->ip_type == SR_TYPE_V1 && offset == ERRCONFIG_V1)
                mask |= ERRCONFIG_STATUS_V1_MASK;
        else if (sr->ip_type == SR_TYPE_V2 && offset == ERRCONFIG_V2)
                mask |= ERRCONFIG_VPBOUNDINTST_V2;

        reg_val = __raw_readl(sr->base + offset);
        reg_val &= ~mask;

        value &= mask;

        reg_val |= value;

        __raw_writel(reg_val, (sr->base + offset));
}

static inline u32 sr_read_reg(struct omap_sr *sr, unsigned offset)
{
        return __raw_readl(sr->base + offset);
}

static struct omap_sr *_sr_lookup(struct voltagedomain *voltdm)
{
        struct omap_sr *sr_info;

        if (!voltdm) {
                pr_err("%s: Null voltage domain passed!\n", __func__);
                return ERR_PTR(-EINVAL);
        }

        list_for_each_entry(sr_info, &sr_list, node) {
                if (voltdm == sr_info->voltdm)
                        return sr_info;
        }

        return ERR_PTR(-ENODATA);
}

static irqreturn_t sr_interrupt(int irq, void *data)
{
        struct omap_sr *sr_info = data;
        u32 status = 0;

        switch (sr_info->ip_type) {
        case SR_TYPE_V1:
                /* Read the status bits */
                status = sr_read_reg(sr_info, ERRCONFIG_V1);

                /* Clear them by writing back */
                sr_write_reg(sr_info, ERRCONFIG_V1, status);
                break;
        case SR_TYPE_V2:
                /* Read the status bits */
                status = sr_read_reg(sr_info, IRQSTATUS);

                /* Clear them by writing back */
                sr_write_reg(sr_info, IRQSTATUS, status);
                break;
        default:
                dev_err(&sr_info->pdev->dev, "UNKNOWN IP type %d\n",
                        sr_info->ip_type);
                return IRQ_NONE;
        }

        if (sr_class->notify)
                sr_class->notify(sr_info, status);

        return IRQ_HANDLED;
}

static void sr_set_clk_length(struct omap_sr *sr)
{
        struct clk *fck;
        u32 fclk_speed;

        fck = clk_get(&sr->pdev->dev, "fck");

        if (IS_ERR(fck)) {
                dev_err(&sr->pdev->dev, "%s: unable to get fck for device %s\n",
                                __func__, dev_name(&sr->pdev->dev));
                return;
        }

        fclk_speed = clk_get_rate(fck);
        clk_put(fck);

        switch (fclk_speed) {
        case 12000000:
                sr->clk_length = SRCLKLENGTH_12MHZ_SYSCLK;
                break;
        case 13000000:
                sr->clk_length = SRCLKLENGTH_13MHZ_SYSCLK;
                break;
        case 19200000:
                sr->clk_length = SRCLKLENGTH_19MHZ_SYSCLK;
                break;
        case 26000000:
                sr->clk_length = SRCLKLENGTH_26MHZ_SYSCLK;
                break;
        case 38400000:
                sr->clk_length = SRCLKLENGTH_38MHZ_SYSCLK;
                break;
        default:
                dev_err(&sr->pdev->dev, "%s: Invalid fclk rate: %d\n",
                        __func__, fclk_speed);
                break;
        }
}

static void sr_start_vddautocomp(struct omap_sr *sr)
{
        if (!sr_class || !(sr_class->enable) || !(sr_class->configure)) {
                dev_warn(&sr->pdev->dev,
                        "%s: smartreflex class driver not registered\n",
                        __func__);
                return;
        }

        if (!sr_class->enable(sr))
                sr->autocomp_active = true;
}

static void sr_stop_vddautocomp(struct omap_sr *sr)
{
        if (!sr_class || !(sr_class->disable)) {
                dev_warn(&sr->pdev->dev,
                        "%s: smartreflex class driver not registered\n",
                        __func__);
                return;
        }

        if (sr->autocomp_active) {
                sr_class->disable(sr, 1);
                sr->autocomp_active = false;
        }
}

/*
 * This function handles the intializations which have to be done
 * only when both sr device and class driver regiter has
 * completed. This will be attempted to be called from both sr class
 * driver register and sr device intializtion API's. Only one call
 * will ultimately succeed.
 *
 * Currently this function registers interrupt handler for a particular SR
 * if smartreflex class driver is already registered and has
 * requested for interrupts and the SR interrupt line in present.
 */
static int sr_late_init(struct omap_sr *sr_info)
{
        struct omap_sr_data *pdata = sr_info->pdev->dev.platform_data;
        struct resource *mem;
        int ret = 0;

        if (sr_class->notify && sr_class->notify_flags && sr_info->irq) {
                ret = request_irq(sr_info->irq, sr_interrupt,
                                  0, sr_info->name, sr_info);
                if (ret)
                        goto error;
                disable_irq(sr_info->irq);
        }

        if (pdata && pdata->enable_on_init)
                sr_start_vddautocomp(sr_info);

        return ret;

error:
        iounmap(sr_info->base);
        mem = platform_get_resource(sr_info->pdev, IORESOURCE_MEM, 0);
        release_mem_region(mem->start, resource_size(mem));
        list_del(&sr_info->node);
        dev_err(&sr_info->pdev->dev, "%s: ERROR in registering"
                "interrupt handler. Smartreflex will"
                "not function as desired\n", __func__);
        kfree(sr_info);

        return ret;
}

static void sr_v1_disable(struct omap_sr *sr)
{
        int timeout = 0;
        int errconf_val = ERRCONFIG_MCUACCUMINTST | ERRCONFIG_MCUVALIDINTST |
                        ERRCONFIG_MCUBOUNDINTST;

        /* Enable MCUDisableAcknowledge interrupt */
        sr_modify_reg(sr, ERRCONFIG_V1,
                        ERRCONFIG_MCUDISACKINTEN, ERRCONFIG_MCUDISACKINTEN);

        /* SRCONFIG - disable SR */
        sr_modify_reg(sr, SRCONFIG, SRCONFIG_SRENABLE, 0x0);

        /* Disable all other SR interrupts and clear the status as needed */
        if (sr_read_reg(sr, ERRCONFIG_V1) & ERRCONFIG_VPBOUNDINTST_V1)
                errconf_val |= ERRCONFIG_VPBOUNDINTST_V1;
        sr_modify_reg(sr, ERRCONFIG_V1,
                        (ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUVALIDINTEN |
                        ERRCONFIG_MCUBOUNDINTEN | ERRCONFIG_VPBOUNDINTEN_V1),
                        errconf_val);

        /*
         * Wait for SR to be disabled.
         * wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
         */
        sr_test_cond_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
                             ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
                             timeout);

        if (timeout >= SR_DISABLE_TIMEOUT)
                dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
                        __func__);

        /* Disable MCUDisableAcknowledge interrupt & clear pending interrupt */
        sr_modify_reg(sr, ERRCONFIG_V1, ERRCONFIG_MCUDISACKINTEN,
                        ERRCONFIG_MCUDISACKINTST);
}

static void sr_v2_disable(struct omap_sr *sr)
{
        int timeout = 0;

        /* Enable MCUDisableAcknowledge interrupt */
        sr_write_reg(sr, IRQENABLE_SET, IRQENABLE_MCUDISABLEACKINT);

        /* SRCONFIG - disable SR */
        sr_modify_reg(sr, SRCONFIG, SRCONFIG_SRENABLE, 0x0);

        /*
         * Disable all other SR interrupts and clear the status
         * write to status register ONLY on need basis - only if status
         * is set.
         */
        if (sr_read_reg(sr, ERRCONFIG_V2) & ERRCONFIG_VPBOUNDINTST_V2)
                sr_modify_reg(sr, ERRCONFIG_V2, ERRCONFIG_VPBOUNDINTEN_V2,
                        ERRCONFIG_VPBOUNDINTST_V2);
        else
                sr_modify_reg(sr, ERRCONFIG_V2, ERRCONFIG_VPBOUNDINTEN_V2,
                                0x0);
        sr_write_reg(sr, IRQENABLE_CLR, (IRQENABLE_MCUACCUMINT |
                        IRQENABLE_MCUVALIDINT |
                        IRQENABLE_MCUBOUNDSINT));
        sr_write_reg(sr, IRQSTATUS, (IRQSTATUS_MCUACCUMINT |
                        IRQSTATUS_MCVALIDINT |
                        IRQSTATUS_MCBOUNDSINT));

        /*
         * Wait for SR to be disabled.
         * wait until IRQSTATUS.MCUDISACKINTST = 1. Typical latency is 1us.
         */
        sr_test_cond_timeout((sr_read_reg(sr, IRQSTATUS) &
                             IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
                             timeout);

        if (timeout >= SR_DISABLE_TIMEOUT)
                dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
                        __func__);

        /* Disable MCUDisableAcknowledge interrupt & clear pending interrupt */
        sr_write_reg(sr, IRQENABLE_CLR, IRQENABLE_MCUDISABLEACKINT);
        sr_write_reg(sr, IRQSTATUS, IRQSTATUS_MCUDISABLEACKINT);
}

static struct omap_sr_nvalue_table *sr_retrieve_nvalue_row(
                                struct omap_sr *sr, u32 efuse_offs)
{
        int i;

        if (!sr->nvalue_table) {
                dev_warn(&sr->pdev->dev, "%s: Missing ntarget value table\n",
                        __func__);
                return NULL;
        }

        for (i = 0; i < sr->nvalue_count; i++) {
                if (sr->nvalue_table[i].efuse_offs == efuse_offs)
                        return &sr->nvalue_table[i];
        }

        return NULL;
}

/* Public Functions */

/**
 * sr_configure_errgen() - Configures the smrtreflex to perform AVS using the
 *                       error generator module.
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the smartreflex class driver to
 * configure the error generator module inside the smartreflex module.
 * SR settings if using the ERROR module inside Smartreflex.
 * SR CLASS 3 by default uses only the ERROR module where as
 * SR CLASS 2 can choose between ERROR module and MINMAXAVG
 * module. Returns 0 on success and error value in case of failure.
 */
int sr_configure_errgen(struct voltagedomain *voltdm)
{
        u32 sr_config, sr_errconfig, errconfig_offs;
        u32 vpboundint_en, vpboundint_st;
        u32 senp_en = 0, senn_en = 0;
        u8 senp_shift, senn_shift;
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return PTR_ERR(sr);
        }

        if (!sr->clk_length)
                sr_set_clk_length(sr);

        senp_en = sr->senp_mod;
        senn_en = sr->senn_mod;

        sr_config = (sr->clk_length << SRCONFIG_SRCLKLENGTH_SHIFT) |
                SRCONFIG_SENENABLE | SRCONFIG_ERRGEN_EN;

        switch (sr->ip_type) {
        case SR_TYPE_V1:
                sr_config |= SRCONFIG_DELAYCTRL;
                senn_shift = SRCONFIG_SENNENABLE_V1_SHIFT;
                senp_shift = SRCONFIG_SENPENABLE_V1_SHIFT;
                errconfig_offs = ERRCONFIG_V1;
                vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V1;
                vpboundint_st = ERRCONFIG_VPBOUNDINTST_V1;
                break;
        case SR_TYPE_V2:
                senn_shift = SRCONFIG_SENNENABLE_V2_SHIFT;
                senp_shift = SRCONFIG_SENPENABLE_V2_SHIFT;
                errconfig_offs = ERRCONFIG_V2;
                vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V2;
                vpboundint_st = ERRCONFIG_VPBOUNDINTST_V2;
                break;
        default:
                dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex"
                        "module without specifying the ip\n", __func__);
                return -EINVAL;
        }

        sr_config |= ((senn_en << senn_shift) | (senp_en << senp_shift));
        sr_write_reg(sr, SRCONFIG, sr_config);
        sr_errconfig = (sr->err_weight << ERRCONFIG_ERRWEIGHT_SHIFT) |
                (sr->err_maxlimit << ERRCONFIG_ERRMAXLIMIT_SHIFT) |
                (sr->err_minlimit <<  ERRCONFIG_ERRMINLIMIT_SHIFT);
        sr_modify_reg(sr, errconfig_offs, (SR_ERRWEIGHT_MASK |
                SR_ERRMAXLIMIT_MASK | SR_ERRMINLIMIT_MASK),
                sr_errconfig);

        /* Enabling the interrupts if the ERROR module is used */
        sr_modify_reg(sr, errconfig_offs, (vpboundint_en | vpboundint_st),
                      vpboundint_en);

        return 0;
}

/**
 * sr_disable_errgen() - Disables SmartReflex AVS module's errgen component
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the smartreflex class driver to
 * disable the error generator module inside the smartreflex module.
 *
 * Returns 0 on success and error value in case of failure.
 */
int sr_disable_errgen(struct voltagedomain *voltdm)
{
        u32 errconfig_offs;
        u32 vpboundint_en, vpboundint_st;
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return PTR_ERR(sr);
        }

        switch (sr->ip_type) {
        case SR_TYPE_V1:
                errconfig_offs = ERRCONFIG_V1;
                vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V1;
                vpboundint_st = ERRCONFIG_VPBOUNDINTST_V1;
                break;
        case SR_TYPE_V2:
                errconfig_offs = ERRCONFIG_V2;
                vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V2;
                vpboundint_st = ERRCONFIG_VPBOUNDINTST_V2;
                break;
        default:
                dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex"
                        "module without specifying the ip\n", __func__);
                return -EINVAL;
        }

        /* Disable the interrupts of ERROR module */
        sr_modify_reg(sr, errconfig_offs, vpboundint_en | vpboundint_st, 0);

        /* Disable the Sensor and errorgen */
        sr_modify_reg(sr, SRCONFIG, SRCONFIG_SENENABLE | SRCONFIG_ERRGEN_EN, 0);

        return 0;
}

/**
 * sr_configure_minmax() - Configures the smrtreflex to perform AVS using the
 *                       minmaxavg module.
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the smartreflex class driver to
 * configure the minmaxavg module inside the smartreflex module.
 * SR settings if using the ERROR module inside Smartreflex.
 * SR CLASS 3 by default uses only the ERROR module where as
 * SR CLASS 2 can choose between ERROR module and MINMAXAVG
 * module. Returns 0 on success and error value in case of failure.
 */
int sr_configure_minmax(struct voltagedomain *voltdm)
{
        u32 sr_config, sr_avgwt;
        u32 senp_en = 0, senn_en = 0;
        u8 senp_shift, senn_shift;
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return PTR_ERR(sr);
        }

        if (!sr->clk_length)
                sr_set_clk_length(sr);

        senp_en = sr->senp_mod;
        senn_en = sr->senn_mod;

        sr_config = (sr->clk_length << SRCONFIG_SRCLKLENGTH_SHIFT) |
                SRCONFIG_SENENABLE |
                (sr->accum_data << SRCONFIG_ACCUMDATA_SHIFT);

        switch (sr->ip_type) {
        case SR_TYPE_V1:
                sr_config |= SRCONFIG_DELAYCTRL;
                senn_shift = SRCONFIG_SENNENABLE_V1_SHIFT;
                senp_shift = SRCONFIG_SENPENABLE_V1_SHIFT;
                break;
        case SR_TYPE_V2:
                senn_shift = SRCONFIG_SENNENABLE_V2_SHIFT;
                senp_shift = SRCONFIG_SENPENABLE_V2_SHIFT;
                break;
        default:
                dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex"
                        "module without specifying the ip\n", __func__);
                return -EINVAL;
        }

        sr_config |= ((senn_en << senn_shift) | (senp_en << senp_shift));
        sr_write_reg(sr, SRCONFIG, sr_config);
        sr_avgwt = (sr->senp_avgweight << AVGWEIGHT_SENPAVGWEIGHT_SHIFT) |
                (sr->senn_avgweight << AVGWEIGHT_SENNAVGWEIGHT_SHIFT);
        sr_write_reg(sr, AVGWEIGHT, sr_avgwt);

        /*
         * Enabling the interrupts if MINMAXAVG module is used.
         * TODO: check if all the interrupts are mandatory
         */
        switch (sr->ip_type) {
        case SR_TYPE_V1:
                sr_modify_reg(sr, ERRCONFIG_V1,
                        (ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUVALIDINTEN |
                        ERRCONFIG_MCUBOUNDINTEN),
                        (ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUACCUMINTST |
                         ERRCONFIG_MCUVALIDINTEN | ERRCONFIG_MCUVALIDINTST |
                         ERRCONFIG_MCUBOUNDINTEN | ERRCONFIG_MCUBOUNDINTST));
                break;
        case SR_TYPE_V2:
                sr_write_reg(sr, IRQSTATUS,
                        IRQSTATUS_MCUACCUMINT | IRQSTATUS_MCVALIDINT |
                        IRQSTATUS_MCBOUNDSINT | IRQSTATUS_MCUDISABLEACKINT);
                sr_write_reg(sr, IRQENABLE_SET,
                        IRQENABLE_MCUACCUMINT | IRQENABLE_MCUVALIDINT |
                        IRQENABLE_MCUBOUNDSINT | IRQENABLE_MCUDISABLEACKINT);
                break;
        default:
                dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex"
                        "module without specifying the ip\n", __func__);
                return -EINVAL;
        }

        return 0;
}

/**
 * sr_enable() - Enables the smartreflex module.
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 * @volt:       The voltage at which the Voltage domain associated with
 *              the smartreflex module is operating at.
 *              This is required only to program the correct Ntarget value.
 *
 * This API is to be called from the smartreflex class driver to
 * enable a smartreflex module. Returns 0 on success. Returns error
 * value if the voltage passed is wrong or if ntarget value is wrong.
 */
int sr_enable(struct voltagedomain *voltdm, unsigned long volt)
{
        struct omap_volt_data *volt_data;
        struct omap_sr *sr = _sr_lookup(voltdm);
        struct omap_sr_nvalue_table *nvalue_row;
        int ret;

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return PTR_ERR(sr);
        }

        volt_data = omap_voltage_get_voltdata(sr->voltdm, volt);

        if (IS_ERR(volt_data)) {
                dev_warn(&sr->pdev->dev, "%s: Unable to get voltage table"
                        "for nominal voltage %ld\n", __func__, volt);
                return PTR_ERR(volt_data);
        }

        nvalue_row = sr_retrieve_nvalue_row(sr, volt_data->sr_efuse_offs);

        if (!nvalue_row) {
                dev_warn(&sr->pdev->dev, "%s: failure getting SR data for this voltage %ld\n",
                         __func__, volt);
                return -ENODATA;
        }

        /* errminlimit is opp dependent and hence linked to voltage */
        sr->err_minlimit = nvalue_row->errminlimit;

        pm_runtime_get_sync(&sr->pdev->dev);

        /* Check if SR is already enabled. If yes do nothing */
        if (sr_read_reg(sr, SRCONFIG) & SRCONFIG_SRENABLE)
                return 0;

        /* Configure SR */
        ret = sr_class->configure(sr);
        if (ret)
                return ret;

        sr_write_reg(sr, NVALUERECIPROCAL, nvalue_row->nvalue);

        /* SRCONFIG - enable SR */
        sr_modify_reg(sr, SRCONFIG, SRCONFIG_SRENABLE, SRCONFIG_SRENABLE);
        return 0;
}

/**
 * sr_disable() - Disables the smartreflex module.
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the smartreflex class driver to
 * disable a smartreflex module.
 */
void sr_disable(struct voltagedomain *voltdm)
{
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return;
        }

        /* Check if SR clocks are already disabled. If yes do nothing */
        if (pm_runtime_suspended(&sr->pdev->dev))
                return;

        /*
         * Disable SR if only it is indeed enabled. Else just
         * disable the clocks.
         */
        if (sr_read_reg(sr, SRCONFIG) & SRCONFIG_SRENABLE) {
                switch (sr->ip_type) {
                case SR_TYPE_V1:
                        sr_v1_disable(sr);
                        break;
                case SR_TYPE_V2:
                        sr_v2_disable(sr);
                        break;
                default:
                        dev_err(&sr->pdev->dev, "UNKNOWN IP type %d\n",
                                sr->ip_type);
                }
        }

        pm_runtime_put_sync_suspend(&sr->pdev->dev);
}

/**
 * sr_register_class() - API to register a smartreflex class parameters.
 * @class_data: The structure containing various sr class specific data.
 *
 * This API is to be called by the smartreflex class driver to register itself
 * with the smartreflex driver during init. Returns 0 on success else the
 * error value.
 */
int sr_register_class(struct omap_sr_class_data *class_data)
{
        struct omap_sr *sr_info;

        if (!class_data) {
                pr_warning("%s:, Smartreflex class data passed is NULL\n",
                        __func__);
                return -EINVAL;
        }

        if (sr_class) {
                pr_warning("%s: Smartreflex class driver already registered\n",
                        __func__);
                return -EBUSY;
        }

        sr_class = class_data;

        /*
         * Call into late init to do intializations that require
         * both sr driver and sr class driver to be initiallized.
         */
        list_for_each_entry(sr_info, &sr_list, node)
                sr_late_init(sr_info);

        return 0;
}

/**
 * omap_sr_enable() -  API to enable SR clocks and to call into the
 *                      registered smartreflex class enable API.
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the kernel in order to enable
 * a particular smartreflex module. This API will do the initial
 * configurations to turn on the smartreflex module and in turn call
 * into the registered smartreflex class enable API.
 */
void omap_sr_enable(struct voltagedomain *voltdm)
{
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return;
        }

        if (!sr->autocomp_active)
                return;

        if (!sr_class || !(sr_class->enable) || !(sr_class->configure)) {
                dev_warn(&sr->pdev->dev, "%s: smartreflex class driver not"
                        "registered\n", __func__);
                return;
        }

        sr_class->enable(sr);
}

/**
 * omap_sr_disable() - API to disable SR without resetting the voltage
 *                      processor voltage
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the kernel in order to disable
 * a particular smartreflex module. This API will in turn call
 * into the registered smartreflex class disable API. This API will tell
 * the smartreflex class disable not to reset the VP voltage after
 * disabling smartreflex.
 */
void omap_sr_disable(struct voltagedomain *voltdm)
{
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return;
        }

        if (!sr->autocomp_active)
                return;

        if (!sr_class || !(sr_class->disable)) {
                dev_warn(&sr->pdev->dev, "%s: smartreflex class driver not"
                        "registered\n", __func__);
                return;
        }

        sr_class->disable(sr, 0);
}

/**
 * omap_sr_disable_reset_volt() - API to disable SR and reset the
 *                              voltage processor voltage
 * @voltdm:     VDD pointer to which the SR module to be configured belongs to.
 *
 * This API is to be called from the kernel in order to disable
 * a particular smartreflex module. This API will in turn call
 * into the registered smartreflex class disable API. This API will tell
 * the smartreflex class disable to reset the VP voltage after
 * disabling smartreflex.
 */
void omap_sr_disable_reset_volt(struct voltagedomain *voltdm)
{
        struct omap_sr *sr = _sr_lookup(voltdm);

        if (IS_ERR(sr)) {
                pr_warning("%s: omap_sr struct for voltdm not found\n", __func__);
                return;
        }

        if (!sr->autocomp_active)
                return;

        if (!sr_class || !(sr_class->disable)) {
                dev_warn(&sr->pdev->dev, "%s: smartreflex class driver not"
                        "registered\n", __func__);
                return;
        }

        sr_class->disable(sr, 1);
}

/**
 * omap_sr_register_pmic() - API to register pmic specific info.
 * @pmic_data:  The structure containing pmic specific data.
 *
 * This API is to be called from the PMIC specific code to register with
 * smartreflex driver pmic specific info. Currently the only info required
 * is the smartreflex init on the PMIC side.
 */
void omap_sr_register_pmic(struct omap_sr_pmic_data *pmic_data)
{
        if (!pmic_data) {
                pr_warning("%s: Trying to register NULL PMIC data structure"
                        "with smartreflex\n", __func__);
                return;
        }

        sr_pmic_data = pmic_data;
}

/* PM Debug FS entries to enable and disable smartreflex. */
static int omap_sr_autocomp_show(void *data, u64 *val)
{
        struct omap_sr *sr_info = data;

        if (!sr_info) {
                pr_warning("%s: omap_sr struct not found\n", __func__);
                return -EINVAL;
        }

        *val = sr_info->autocomp_active;

        return 0;
}

static int omap_sr_autocomp_store(void *data, u64 val)
{
        struct omap_sr *sr_info = data;

        if (!sr_info) {
                pr_warning("%s: omap_sr struct not found\n", __func__);
                return -EINVAL;
        }

        /* Sanity check */
        if (val > 1) {
                pr_warning("%s: Invalid argument %lld\n", __func__, val);
                return -EINVAL;
        }

        /* control enable/disable only if there is a delta in value */
        if (sr_info->autocomp_active != val) {
                if (!val)
                        sr_stop_vddautocomp(sr_info);
                else
                        sr_start_vddautocomp(sr_info);
        }

        return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(pm_sr_fops, omap_sr_autocomp_show,
                        omap_sr_autocomp_store, "%llu\n");

static int __init omap_sr_probe(struct platform_device *pdev)
{
        struct omap_sr *sr_info;
        struct omap_sr_data *pdata = pdev->dev.platform_data;
        struct resource *mem, *irq;
        struct dentry *nvalue_dir;
        int i, ret = 0;

        sr_info = kzalloc(sizeof(struct omap_sr), GFP_KERNEL);
        if (!sr_info) {
                dev_err(&pdev->dev, "%s: unable to allocate sr_info\n",
                        __func__);
                return -ENOMEM;
        }

        platform_set_drvdata(pdev, sr_info);

        if (!pdata) {
                dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
                ret = -EINVAL;
                goto err_free_devinfo;
        }

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!mem) {
                dev_err(&pdev->dev, "%s: no mem resource\n", __func__);
                ret = -ENODEV;
                goto err_free_devinfo;
        }

        mem = request_mem_region(mem->start, resource_size(mem),
                                        dev_name(&pdev->dev));
        if (!mem) {
                dev_err(&pdev->dev, "%s: no mem region\n", __func__);
                ret = -EBUSY;
                goto err_free_devinfo;
        }

        irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

        pm_runtime_enable(&pdev->dev);
        pm_runtime_irq_safe(&pdev->dev);

        sr_info->name = kasprintf(GFP_KERNEL, "%s", pdata->name);
        if (!sr_info->name) {
                dev_err(&pdev->dev, "%s: Unable to alloc SR instance name\n",
                        __func__);
                ret = -ENOMEM;
                goto err_release_region;
        }

        sr_info->pdev = pdev;
        sr_info->srid = pdev->id;
        sr_info->voltdm = pdata->voltdm;
        sr_info->nvalue_table = pdata->nvalue_table;
        sr_info->nvalue_count = pdata->nvalue_count;
        sr_info->senn_mod = pdata->senn_mod;
        sr_info->senp_mod = pdata->senp_mod;
        sr_info->err_weight = pdata->err_weight;
        sr_info->err_maxlimit = pdata->err_maxlimit;
        sr_info->accum_data = pdata->accum_data;
        sr_info->senn_avgweight = pdata->senn_avgweight;
        sr_info->senp_avgweight = pdata->senp_avgweight;
        sr_info->autocomp_active = false;
        sr_info->ip_type = pdata->ip_type;

        sr_info->base = ioremap(mem->start, resource_size(mem));
        if (!sr_info->base) {
                dev_err(&pdev->dev, "%s: ioremap fail\n", __func__);
                ret = -ENOMEM;
                goto err_free_name;
        }

        if (irq)
                sr_info->irq = irq->start;

        sr_set_clk_length(sr_info);

        list_add(&sr_info->node, &sr_list);

        /*
         * Call into late init to do intializations that require
         * both sr driver and sr class driver to be initiallized.
         */
        if (sr_class) {
                ret = sr_late_init(sr_info);
                if (ret) {
                        pr_warning("%s: Error in SR late init\n", __func__);
                        goto err_iounmap;
                }
        }

        dev_info(&pdev->dev, "%s: SmartReflex driver initialized\n", __func__);
        if (!sr_dbg_dir) {
                sr_dbg_dir = debugfs_create_dir("smartreflex", NULL);
                if (IS_ERR_OR_NULL(sr_dbg_dir)) {
                        ret = PTR_ERR(sr_dbg_dir);
                        pr_err("%s:sr debugfs dir creation failed(%d)\n",
                                __func__, ret);
                        goto err_iounmap;
                }
        }

        sr_info->dbg_dir = debugfs_create_dir(sr_info->name, sr_dbg_dir);
        if (IS_ERR_OR_NULL(sr_info->dbg_dir)) {
                dev_err(&pdev->dev, "%s: Unable to create debugfs directory\n",
                        __func__);
                ret = PTR_ERR(sr_info->dbg_dir);
                goto err_debugfs;
        }

        (void) debugfs_create_file("autocomp", S_IRUGO | S_IWUSR,
                        sr_info->dbg_dir, (void *)sr_info, &pm_sr_fops);
        (void) debugfs_create_x32("errweight", S_IRUGO, sr_info->dbg_dir,
                        &sr_info->err_weight);
        (void) debugfs_create_x32("errmaxlimit", S_IRUGO, sr_info->dbg_dir,
                        &sr_info->err_maxlimit);

        nvalue_dir = debugfs_create_dir("nvalue", sr_info->dbg_dir);
        if (IS_ERR_OR_NULL(nvalue_dir)) {
                dev_err(&pdev->dev, "%s: Unable to create debugfs directory"
                        "for n-values\n", __func__);
                ret = PTR_ERR(nvalue_dir);
                goto err_debugfs;
        }

        if (sr_info->nvalue_count == 0 || !sr_info->nvalue_table) {
                dev_warn(&pdev->dev, "%s: %s: No Voltage table for the corresponding vdd. Cannot create debugfs entries for n-values\n",
                         __func__, sr_info->name);

                ret = -ENODATA;
                goto err_debugfs;
        }

        for (i = 0; i < sr_info->nvalue_count; i++) {
                char name[NVALUE_NAME_LEN + 1];

                snprintf(name, sizeof(name), "volt_%lu",
                                sr_info->nvalue_table[i].volt_nominal);
                (void) debugfs_create_x32(name, S_IRUGO | S_IWUSR, nvalue_dir,
                                &(sr_info->nvalue_table[i].nvalue));
                snprintf(name, sizeof(name), "errminlimit_%lu",
                         sr_info->nvalue_table[i].volt_nominal);
                (void) debugfs_create_x32(name, S_IRUGO | S_IWUSR, nvalue_dir,
                                &(sr_info->nvalue_table[i].errminlimit));

        }

        return ret;

err_debugfs:
        debugfs_remove_recursive(sr_info->dbg_dir);
err_iounmap:
        list_del(&sr_info->node);
        iounmap(sr_info->base);
err_free_name:
        kfree(sr_info->name);
err_release_region:
        release_mem_region(mem->start, resource_size(mem));

err_free_devinfo:
        kfree(sr_info);

        return ret;
}

static int omap_sr_remove(struct platform_device *pdev)
{
        struct omap_sr_data *pdata = pdev->dev.platform_data;
        struct omap_sr *sr_info;
        struct resource *mem;

        if (!pdata) {
                dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
                return -EINVAL;
        }

        sr_info = _sr_lookup(pdata->voltdm);
        if (IS_ERR(sr_info)) {
                dev_warn(&pdev->dev, "%s: omap_sr struct not found\n",
                        __func__);
                return PTR_ERR(sr_info);
        }

        if (sr_info->autocomp_active)
                sr_stop_vddautocomp(sr_info);
        if (sr_info->dbg_dir)
                debugfs_remove_recursive(sr_info->dbg_dir);

        list_del(&sr_info->node);
        iounmap(sr_info->base);
        kfree(sr_info->name);
        kfree(sr_info);
        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        release_mem_region(mem->start, resource_size(mem));

        return 0;
}

static void omap_sr_shutdown(struct platform_device *pdev)
{
        struct omap_sr_data *pdata = pdev->dev.platform_data;
        struct omap_sr *sr_info;

        if (!pdata) {
                dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
                return;
        }

        sr_info = _sr_lookup(pdata->voltdm);
        if (IS_ERR(sr_info)) {
                dev_warn(&pdev->dev, "%s: omap_sr struct not found\n",
                        __func__);
                return;
        }

        if (sr_info->autocomp_active)
                sr_stop_vddautocomp(sr_info);

        return;
}

static struct platform_driver smartreflex_driver = {
        .remove         = omap_sr_remove,
        .shutdown       = omap_sr_shutdown,
        .driver         = {
                .name   = "smartreflex",
        },
};

static int __init sr_init(void)
{
        int ret = 0;

        /*
         * sr_init is a late init. If by then a pmic specific API is not
         * registered either there is no need for anything to be done on
         * the PMIC side or somebody has forgotten to register a PMIC
         * handler. Warn for the second condition.
         */
        if (sr_pmic_data && sr_pmic_data->sr_pmic_init)
                sr_pmic_data->sr_pmic_init();
        else
                pr_warning("%s: No PMIC hook to init smartreflex\n", __func__);

        ret = platform_driver_probe(&smartreflex_driver, omap_sr_probe);
        if (ret) {
                pr_err("%s: platform driver register failed for SR\n",
                        __func__);
                return ret;
        }

        return 0;
}
late_initcall(sr_init);

static void __exit sr_exit(void)
{
        platform_driver_unregister(&smartreflex_driver);
}
module_exit(sr_exit);

MODULE_DESCRIPTION("OMAP Smartreflex Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_AUTHOR("Texas Instruments Inc");