OMAP3: PM: Adding smartreflex driver support.

SmartReflex modules do adaptive voltage control for real-time
voltage adjustments. With Smartreflex the power supply voltage
can be adapted to the silicon performance(manufacturing process,
temperature induced performance, age induced performance etc).

There are differnet classes of smartreflex implementation.
	Class-0: Manufacturing Test Calibration
	Class-1: Boot-Time Software Calibration
	Class-2: Continuous Software Calibration
	Class-3: Continuous Hardware Calibration
	Class-4: Fully Integrated Power Management

OMAP3 has two smartreflex modules one associated with VDD MPU and the
other associated with VDD CORE.
This patch adds support for  smartreflex driver. The driver is designed
for Class-1 , Class-2 and Class-3 support and is  a platform driver.
Smartreflex driver can be enabled through a Kconfig option
"SmartReflex support" under "System type"->"TI OMAP implementations" menu.

Smartreflex autocompensation feature can be enabled runtime through
a debug fs option.
To enable smartreflex autocompensation feature
	echo 1 > /debug/voltage/vdd_<X>/smartreflex/autocomp
To disable smartreflex autocompensation feature
	echo 0 > /debug/voltage/vdd_<X>/smartreflex/autocomp

where X can be mpu, core , iva etc.

This patch contains code originally in linux omap pm branch.
Major contributors to this driver are
Lesly A M, Rajendra Nayak, Kalle Jokiniemi, Paul Walmsley,
Nishant Menon, Kevin Hilman.

Signed-off-by: Thara Gopinath <thara@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 983 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/smartreflex.c b/arch/arm/mach-omap2/smartreflex.c
new file mode 100644
index 000000000000..eee23d0f50de
--- /dev/null
+++ b/arch/arm/mach-omap2/smartreflex.c
@@ -0,0 +1,983 @@
+/*
+ * OMAP SmartReflex Voltage Control
+ *
+ * Author: Thara Gopinath	<thara@ti.com>
+ *
+ * Copyright (C) 2010 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/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 <plat/common.h>
+#include <plat/smartreflex.h>
+
+#include "pm.h"
+
+#define SMARTREFLEX_NAME_LEN	16
+#define SR_DISABLE_TIMEOUT	200
+
+struct omap_sr {
+	int				srid;
+	int				ip_type;
+	int				nvalue_count;
+	bool				autocomp_active;
+	u32				clk_length;
+	u32				err_weight;
+	u32				err_minlimit;
+	u32				err_maxlimit;
+	u32				accum_data;
+	u32				senn_avgweight;
+	u32				senp_avgweight;
+	u32				senp_mod;
+	u32				senn_mod;
+	unsigned int			irq;
+	void __iomem			*base;
+	struct platform_device		*pdev;
+	struct list_head		node;
+	struct omap_sr_nvalue_table	*nvalue_table;
+	struct voltagedomain		*voltdm;
+};
+
+/* 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 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;
+	u32 errconfig_offs = 0, errconfig_mask = 0;
+
+	reg_val = __raw_readl(sr->base + offset);
+	reg_val &= ~mask;
+
+	/*
+	 * 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) {
+		errconfig_offs = ERRCONFIG_V1;
+		errconfig_mask = ERRCONFIG_STATUS_V1_MASK;
+	} else if (sr->ip_type == SR_TYPE_V2) {
+		errconfig_offs = ERRCONFIG_V2;
+		errconfig_mask = ERRCONFIG_VPBOUNDINTST_V2;
+	}
+
+	if (offset == errconfig_offs)
+		reg_val &= ~errconfig_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 = (struct omap_sr *)data;
+	u32 status = 0;
+
+	if (sr_info->ip_type == 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);
+	} else if (sr_info->ip_type == SR_TYPE_V2) {
+		/* Read the status bits */
+		sr_read_reg(sr_info, IRQSTATUS);
+
+		/* Clear them by writing back */
+		sr_write_reg(sr_info, IRQSTATUS, status);
+	}
+
+	if (sr_class->class_type == SR_CLASS2 && sr_class->notify)
+		sr_class->notify(sr_info->voltdm, status);
+
+	return IRQ_HANDLED;
+}
+
+static void sr_set_clk_length(struct omap_sr *sr)
+{
+	struct clk *sys_ck;
+	u32 sys_clk_speed;
+
+	sys_ck = clk_get(NULL, "sys_ck");
+	if (IS_ERR(sys_ck)) {
+		dev_err(&sr->pdev->dev, "%s: unable to get sys clk\n",
+			__func__);
+		return;
+	}
+	sys_clk_speed = clk_get_rate(sys_ck);
+	clk_put(sys_ck);
+
+	switch (sys_clk_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 sysclk value: %d\n",
+			__func__, sys_clk_speed);
+		break;
+	}
+}
+
+static void sr_set_regfields(struct omap_sr *sr)
+{
+	/*
+	 * For time being these values are defined in smartreflex.h
+	 * and populated during init. May be they can be moved to board
+	 * file or pmic specific data structure. In that case these structure
+	 * fields will have to be populated using the pdata or pmic structure.
+	 */
+	if (cpu_is_omap34xx()) {
+		sr->err_weight = OMAP3430_SR_ERRWEIGHT;
+		sr->err_maxlimit = OMAP3430_SR_ERRMAXLIMIT;
+		sr->accum_data = OMAP3430_SR_ACCUMDATA;
+		if (!(strcmp(sr->voltdm->name, "mpu"))) {
+			sr->senn_avgweight = OMAP3430_SR1_SENNAVGWEIGHT;
+			sr->senp_avgweight = OMAP3430_SR1_SENPAVGWEIGHT;
+		} else {
+			sr->senn_avgweight = OMAP3430_SR2_SENNAVGWEIGHT;
+			sr->senp_avgweight = OMAP3430_SR2_SENPAVGWEIGHT;
+		}
+	}
+}
+
+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->voltdm))
+		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->voltdm, 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.
+ *
+ * Currenly this function registers interrrupt 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)
+{
+	char *name;
+	struct omap_sr_data *pdata = sr_info->pdev->dev.platform_data;
+	struct resource *mem;
+	int ret = 0;
+
+	if (sr_class->class_type == SR_CLASS2 &&
+		sr_class->notify_flags && sr_info->irq) {
+
+		name = kzalloc(SMARTREFLEX_NAME_LEN + 1, GFP_KERNEL);
+		strcpy(name, "sr_");
+		strcat(name, sr_info->voltdm->name);
+		ret = request_irq(sr_info->irq, sr_interrupt,
+				0, name, (void *)sr_info);
+		if (ret)
+			goto error;
+	}
+
+	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;
+
+	/* 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 */
+	sr_modify_reg(sr, ERRCONFIG_V1,
+			(ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUVALIDINTEN |
+			ERRCONFIG_MCUBOUNDINTEN | ERRCONFIG_VPBOUNDINTEN_V1),
+			(ERRCONFIG_MCUACCUMINTST | ERRCONFIG_MCUVALIDINTST |
+			ERRCONFIG_MCUBOUNDINTST |
+			ERRCONFIG_VPBOUNDINTST_V1));
+
+	/*
+	 * Wait for SR to be disabled.
+	 * wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
+	 */
+	omap_test_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 */
+	sr_modify_reg(sr, ERRCONFIG_V2, ERRCONFIG_VPBOUNDINTEN_V2,
+			ERRCONFIG_VPBOUNDINTST_V2);
+	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.
+	 */
+	omap_test_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 u32 sr_retrieve_nvalue(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 0;
+	}
+
+	for (i = 0; i < sr->nvalue_count; i++) {
+		if (sr->nvalue_table[i].efuse_offs == efuse_offs)
+			return sr->nvalue_table[i].nvalue;
+	}
+
+	return 0;
+}
+
+/* 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, vpboundint_en;
+	u32 vpboundint_st, 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 sr_%s not found\n",
+			__func__, voltdm->name);
+		return -EINVAL;
+	}
+
+	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;
+
+	if (sr->ip_type == 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;
+	} else if (sr->ip_type == 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;
+	} else {
+		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_en | vpboundint_st));
+
+	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 sr_%s not found\n",
+			__func__, voltdm->name);
+		return -EINVAL;
+	}
+
+	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);
+
+	if (sr->ip_type == SR_TYPE_V1) {
+		sr_config |= SRCONFIG_DELAYCTRL;
+		senn_shift = SRCONFIG_SENNENABLE_V1_SHIFT;
+		senp_shift = SRCONFIG_SENPENABLE_V1_SHIFT;
+	} else if (sr->ip_type == SR_TYPE_V2) {
+		senn_shift = SRCONFIG_SENNENABLE_V2_SHIFT;
+		senp_shift = SRCONFIG_SENPENABLE_V2_SHIFT;
+	} else {
+		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
+	 */
+	if (sr->ip_type == 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));
+	} else if (sr->ip_type == 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);
+	}
+
+	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)
+{
+	u32 nvalue_reciprocal;
+	struct omap_volt_data *volt_data;
+	struct omap_sr *sr = _sr_lookup(voltdm);
+	int ret;
+
+	if (IS_ERR(sr)) {
+		pr_warning("%s: omap_sr struct for sr_%s not found\n",
+			__func__, voltdm->name);
+		return -EINVAL;
+	}
+
+	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 -ENODATA;
+	}
+
+	nvalue_reciprocal = sr_retrieve_nvalue(sr, volt_data->sr_efuse_offs);
+
+	if (!nvalue_reciprocal) {
+		dev_warn(&sr->pdev->dev, "%s: NVALUE = 0 at voltage %ld\n",
+			__func__, volt);
+		return -ENODATA;
+	}
+
+	/* errminlimit is opp dependent and hence linked to voltage */
+	sr->err_minlimit = volt_data->sr_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(voltdm);
+	if (ret)
+		return ret;
+
+	sr_write_reg(sr, NVALUERECIPROCAL, nvalue_reciprocal);
+
+	/* 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 sr_%s not found\n",
+			__func__, voltdm->name);
+		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) {
+		if (sr->ip_type == SR_TYPE_V1)
+			sr_v1_disable(sr);
+		else if (sr->ip_type == SR_TYPE_V2)
+			sr_v2_disable(sr);
+	}
+
+	pm_runtime_put_sync(&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 sr_%s not found\n",
+			__func__, voltdm->name);
+		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(voltdm);
+}
+
+/**
+ * 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 sr_%s not found\n",
+			__func__, voltdm->name);
+		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(voltdm, 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 sr_%s not found\n",
+			__func__, voltdm->name);
+		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(voltdm, 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 enteries to enable disable smartreflex. */
+static int omap_sr_autocomp_show(void *data, u64 *val)
+{
+	struct omap_sr *sr_info = (struct omap_sr *) data;
+
+	if (!sr_info) {
+		pr_warning("%s: omap_sr struct for sr_%s not found\n",
+			__func__, sr_info->voltdm->name);
+		return -EINVAL;
+	}
+
+	*val = sr_info->autocomp_active;
+
+	return 0;
+}
+
+static int omap_sr_autocomp_store(void *data, u64 val)
+{
+	struct omap_sr *sr_info = (struct omap_sr *) data;
+
+	if (!sr_info) {
+		pr_warning("%s: omap_sr struct for sr_%s not found\n",
+			__func__, sr_info->voltdm->name);
+		return -EINVAL;
+	}
+
+	/* Sanity check */
+	if (val && (val != 1)) {
+		pr_warning("%s: Invalid argument %lld\n", __func__, val);
+		return -EINVAL;
+	}
+
+	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 = kzalloc(sizeof(struct omap_sr), GFP_KERNEL);
+	struct omap_sr_data *pdata = pdev->dev.platform_data;
+	struct resource *mem, *irq;
+	struct dentry *vdd_dbg_dir, *dbg_dir;
+	int ret = 0;
+
+	if (!sr_info) {
+		dev_err(&pdev->dev, "%s: unable to allocate sr_info\n",
+			__func__);
+		return -ENOMEM;
+	}
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
+		return -EINVAL;
+	}
+
+	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;
+	}
+
+	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+
+	pm_runtime_enable(&pdev->dev);
+
+	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->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_release_region;
+	}
+
+	if (irq)
+		sr_info->irq = irq->start;
+
+	sr_set_clk_length(sr_info);
+	sr_set_regfields(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__);
+			return ret;
+		}
+	}
+
+	dev_info(&pdev->dev, "%s: SmartReflex driver initialized\n", __func__);
+
+	/*
+	 * If the voltage domain debugfs directory is not created, do
+	 * not try to create rest of the debugfs entries.
+	 */
+	vdd_dbg_dir = omap_voltage_get_dbgdir(sr_info->voltdm);
+	if (!vdd_dbg_dir)
+		return -EINVAL;
+
+	dbg_dir = debugfs_create_dir("smartreflex", vdd_dbg_dir);
+	if (IS_ERR(dbg_dir)) {
+		dev_err(&pdev->dev, "%s: Unable to create debugfs directory\n",
+			__func__);
+		return PTR_ERR(dbg_dir);
+	}
+
+	(void) debugfs_create_file("autocomp", S_IRUGO | S_IWUGO, dbg_dir,
+				(void *)sr_info, &pm_sr_fops);
+
+	return ret;
+
+err_release_region:
+	release_mem_region(mem->start, resource_size(mem));
+err_free_devinfo:
+	kfree(sr_info);
+
+	return ret;
+}
+
+static int __devexit 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 (!sr_info) {
+		dev_warn(&pdev->dev, "%s: omap_sr struct not found\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	if (sr_info->autocomp_active)
+		sr_stop_vddautocomp(sr_info);
+
+	list_del(&sr_info->node);
+	iounmap(sr_info->base);
+	kfree(sr_info);
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(mem->start, resource_size(mem));
+
+	return 0;
+}
+
+static struct platform_driver smartreflex_driver = {
+	.remove         = omap_sr_remove,
+	.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;
+}
+
+static void __exit sr_exit(void)
+{
+	platform_driver_unregister(&smartreflex_driver);
+}
+late_initcall(sr_init);
+module_exit(sr_exit);
+
+MODULE_DESCRIPTION("OMAP Smartreflex Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_AUTHOR("Texas Instruments Inc");