PM: AVS: qcom-cpr: Move the driver to the qcom specific drivers

The avs drivers are all SoC specific drivers that doesn't share any code.
Instead they are located in a directory, mostly to keep similar
functionality together. From a maintenance point of view, it makes better
sense to collect SoC specific drivers like these, into the SoC specific
directories.

Therefore, let's move the qcom-cpr driver to the qcom directory.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Niklas Cassel <nks@flawful.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 1805 insertions, 0 deletions

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 3dc3e3d61ea3..6a3b69b43ad5 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -26,6 +26,22 @@ config QCOM_COMMAND_DB
 	  resource on a RPM-hardened platform must use this database to get
 	  SoC specific identifier and information for the shared resources.
 
+config QCOM_CPR
+	tristate "QCOM Core Power Reduction (CPR) support"
+	depends on ARCH_QCOM && HAS_IOMEM
+	select PM_OPP
+	select REGMAP
+	help
+	  Say Y here to enable support for the CPR hardware found on Qualcomm
+	  SoCs like QCS404.
+
+	  This driver populates CPU OPPs tables and makes adjustments to the
+	  tables based on feedback from the CPR hardware. If you want to do
+	  CPUfrequency scaling say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called qcom-cpr
+
 config QCOM_GENI_SE
 	tristate "QCOM GENI Serial Engine Driver"
 	depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 93392d9dc7f7..ad675a6593d0 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -3,6 +3,7 @@ CFLAGS_rpmh-rsc.o := -I$(src)
 obj-$(CONFIG_QCOM_AOSS_QMP) +=	qcom_aoss.o
 obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
 obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
+obj-$(CONFIG_QCOM_CPR)		+= cpr.o
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
diff --git a/drivers/soc/qcom/cpr.c b/drivers/soc/qcom/cpr.c
new file mode 100644
index 000000000000..b24cc77d1889
--- /dev/null
+++ b/drivers/soc/qcom/cpr.c
@@ -0,0 +1,1788 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_opp.h>
+#include <linux/interrupt.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regulator/consumer.h>
+#include <linux/clk.h>
+#include <linux/nvmem-consumer.h>
+
+/* Register Offsets for RB-CPR and Bit Definitions */
+
+/* RBCPR Version Register */
+#define REG_RBCPR_VERSION		0
+#define RBCPR_VER_2			0x02
+#define FLAGS_IGNORE_1ST_IRQ_STATUS	BIT(0)
+
+/* RBCPR Gate Count and Target Registers */
+#define REG_RBCPR_GCNT_TARGET(n)	(0x60 + 4 * (n))
+
+#define RBCPR_GCNT_TARGET_TARGET_SHIFT	0
+#define RBCPR_GCNT_TARGET_TARGET_MASK	GENMASK(11, 0)
+#define RBCPR_GCNT_TARGET_GCNT_SHIFT	12
+#define RBCPR_GCNT_TARGET_GCNT_MASK	GENMASK(9, 0)
+
+/* RBCPR Timer Control */
+#define REG_RBCPR_TIMER_INTERVAL	0x44
+#define REG_RBIF_TIMER_ADJUST		0x4c
+
+#define RBIF_TIMER_ADJ_CONS_UP_MASK	GENMASK(3, 0)
+#define RBIF_TIMER_ADJ_CONS_UP_SHIFT	0
+#define RBIF_TIMER_ADJ_CONS_DOWN_MASK	GENMASK(3, 0)
+#define RBIF_TIMER_ADJ_CONS_DOWN_SHIFT	4
+#define RBIF_TIMER_ADJ_CLAMP_INT_MASK	GENMASK(7, 0)
+#define RBIF_TIMER_ADJ_CLAMP_INT_SHIFT	8
+
+/* RBCPR Config Register */
+#define REG_RBIF_LIMIT			0x48
+#define RBIF_LIMIT_CEILING_MASK		GENMASK(5, 0)
+#define RBIF_LIMIT_CEILING_SHIFT	6
+#define RBIF_LIMIT_FLOOR_BITS		6
+#define RBIF_LIMIT_FLOOR_MASK		GENMASK(5, 0)
+
+#define RBIF_LIMIT_CEILING_DEFAULT	RBIF_LIMIT_CEILING_MASK
+#define RBIF_LIMIT_FLOOR_DEFAULT	0
+
+#define REG_RBIF_SW_VLEVEL		0x94
+#define RBIF_SW_VLEVEL_DEFAULT		0x20
+
+#define REG_RBCPR_STEP_QUOT		0x80
+#define RBCPR_STEP_QUOT_STEPQUOT_MASK	GENMASK(7, 0)
+#define RBCPR_STEP_QUOT_IDLE_CLK_MASK	GENMASK(3, 0)
+#define RBCPR_STEP_QUOT_IDLE_CLK_SHIFT	8
+
+/* RBCPR Control Register */
+#define REG_RBCPR_CTL			0x90
+
+#define RBCPR_CTL_LOOP_EN			BIT(0)
+#define RBCPR_CTL_TIMER_EN			BIT(3)
+#define RBCPR_CTL_SW_AUTO_CONT_ACK_EN		BIT(5)
+#define RBCPR_CTL_SW_AUTO_CONT_NACK_DN_EN	BIT(6)
+#define RBCPR_CTL_COUNT_MODE			BIT(10)
+#define RBCPR_CTL_UP_THRESHOLD_MASK	GENMASK(3, 0)
+#define RBCPR_CTL_UP_THRESHOLD_SHIFT	24
+#define RBCPR_CTL_DN_THRESHOLD_MASK	GENMASK(3, 0)
+#define RBCPR_CTL_DN_THRESHOLD_SHIFT	28
+
+/* RBCPR Ack/Nack Response */
+#define REG_RBIF_CONT_ACK_CMD		0x98
+#define REG_RBIF_CONT_NACK_CMD		0x9c
+
+/* RBCPR Result status Register */
+#define REG_RBCPR_RESULT_0		0xa0
+
+#define RBCPR_RESULT0_BUSY_SHIFT	19
+#define RBCPR_RESULT0_BUSY_MASK		BIT(RBCPR_RESULT0_BUSY_SHIFT)
+#define RBCPR_RESULT0_ERROR_LT0_SHIFT	18
+#define RBCPR_RESULT0_ERROR_SHIFT	6
+#define RBCPR_RESULT0_ERROR_MASK	GENMASK(11, 0)
+#define RBCPR_RESULT0_ERROR_STEPS_SHIFT	2
+#define RBCPR_RESULT0_ERROR_STEPS_MASK	GENMASK(3, 0)
+#define RBCPR_RESULT0_STEP_UP_SHIFT	1
+
+/* RBCPR Interrupt Control Register */
+#define REG_RBIF_IRQ_EN(n)		(0x100 + 4 * (n))
+#define REG_RBIF_IRQ_CLEAR		0x110
+#define REG_RBIF_IRQ_STATUS		0x114
+
+#define CPR_INT_DONE		BIT(0)
+#define CPR_INT_MIN		BIT(1)
+#define CPR_INT_DOWN		BIT(2)
+#define CPR_INT_MID		BIT(3)
+#define CPR_INT_UP		BIT(4)
+#define CPR_INT_MAX		BIT(5)
+#define CPR_INT_CLAMP		BIT(6)
+#define CPR_INT_ALL	(CPR_INT_DONE | CPR_INT_MIN | CPR_INT_DOWN | \
+			CPR_INT_MID | CPR_INT_UP | CPR_INT_MAX | CPR_INT_CLAMP)
+#define CPR_INT_DEFAULT	(CPR_INT_UP | CPR_INT_DOWN)
+
+#define CPR_NUM_RING_OSC	8
+
+/* CPR eFuse parameters */
+#define CPR_FUSE_TARGET_QUOT_BITS_MASK	GENMASK(11, 0)
+
+#define CPR_FUSE_MIN_QUOT_DIFF		50
+
+#define FUSE_REVISION_UNKNOWN		(-1)
+
+enum voltage_change_dir {
+	NO_CHANGE,
+	DOWN,
+	UP,
+};
+
+struct cpr_fuse {
+	char *ring_osc;
+	char *init_voltage;
+	char *quotient;
+	char *quotient_offset;
+};
+
+struct fuse_corner_data {
+	int ref_uV;
+	int max_uV;
+	int min_uV;
+	int max_volt_scale;
+	int max_quot_scale;
+	/* fuse quot */
+	int quot_offset;
+	int quot_scale;
+	int quot_adjust;
+	/* fuse quot_offset */
+	int quot_offset_scale;
+	int quot_offset_adjust;
+};
+
+struct cpr_fuses {
+	int init_voltage_step;
+	int init_voltage_width;
+	struct fuse_corner_data *fuse_corner_data;
+};
+
+struct corner_data {
+	unsigned int fuse_corner;
+	unsigned long freq;
+};
+
+struct cpr_desc {
+	unsigned int num_fuse_corners;
+	int min_diff_quot;
+	int *step_quot;
+
+	unsigned int		timer_delay_us;
+	unsigned int		timer_cons_up;
+	unsigned int		timer_cons_down;
+	unsigned int		up_threshold;
+	unsigned int		down_threshold;
+	unsigned int		idle_clocks;
+	unsigned int		gcnt_us;
+	unsigned int		vdd_apc_step_up_limit;
+	unsigned int		vdd_apc_step_down_limit;
+	unsigned int		clamp_timer_interval;
+
+	struct cpr_fuses cpr_fuses;
+	bool reduce_to_fuse_uV;
+	bool reduce_to_corner_uV;
+};
+
+struct acc_desc {
+	unsigned int	enable_reg;
+	u32		enable_mask;
+
+	struct reg_sequence	*config;
+	struct reg_sequence	*settings;
+	int			num_regs_per_fuse;
+};
+
+struct cpr_acc_desc {
+	const struct cpr_desc *cpr_desc;
+	const struct acc_desc *acc_desc;
+};
+
+struct fuse_corner {
+	int min_uV;
+	int max_uV;
+	int uV;
+	int quot;
+	int step_quot;
+	const struct reg_sequence *accs;
+	int num_accs;
+	unsigned long max_freq;
+	u8 ring_osc_idx;
+};
+
+struct corner {
+	int min_uV;
+	int max_uV;
+	int uV;
+	int last_uV;
+	int quot_adjust;
+	u32 save_ctl;
+	u32 save_irq;
+	unsigned long freq;
+	struct fuse_corner *fuse_corner;
+};
+
+struct cpr_drv {
+	unsigned int		num_corners;
+	unsigned int		ref_clk_khz;
+
+	struct generic_pm_domain pd;
+	struct device		*dev;
+	struct device		*attached_cpu_dev;
+	struct mutex		lock;
+	void __iomem		*base;
+	struct corner		*corner;
+	struct regulator	*vdd_apc;
+	struct clk		*cpu_clk;
+	struct regmap		*tcsr;
+	bool			loop_disabled;
+	u32			gcnt;
+	unsigned long		flags;
+
+	struct fuse_corner	*fuse_corners;
+	struct corner		*corners;
+
+	const struct cpr_desc *desc;
+	const struct acc_desc *acc_desc;
+	const struct cpr_fuse *cpr_fuses;
+
+	struct dentry *debugfs;
+};
+
+static bool cpr_is_allowed(struct cpr_drv *drv)
+{
+	return !drv->loop_disabled;
+}
+
+static void cpr_write(struct cpr_drv *drv, u32 offset, u32 value)
+{
+	writel_relaxed(value, drv->base + offset);
+}
+
+static u32 cpr_read(struct cpr_drv *drv, u32 offset)
+{
+	return readl_relaxed(drv->base + offset);
+}
+
+static void
+cpr_masked_write(struct cpr_drv *drv, u32 offset, u32 mask, u32 value)
+{
+	u32 val;
+
+	val = readl_relaxed(drv->base + offset);
+	val &= ~mask;
+	val |= value & mask;
+	writel_relaxed(val, drv->base + offset);
+}
+
+static void cpr_irq_clr(struct cpr_drv *drv)
+{
+	cpr_write(drv, REG_RBIF_IRQ_CLEAR, CPR_INT_ALL);
+}
+
+static void cpr_irq_clr_nack(struct cpr_drv *drv)
+{
+	cpr_irq_clr(drv);
+	cpr_write(drv, REG_RBIF_CONT_NACK_CMD, 1);
+}
+
+static void cpr_irq_clr_ack(struct cpr_drv *drv)
+{
+	cpr_irq_clr(drv);
+	cpr_write(drv, REG_RBIF_CONT_ACK_CMD, 1);
+}
+
+static void cpr_irq_set(struct cpr_drv *drv, u32 int_bits)
+{
+	cpr_write(drv, REG_RBIF_IRQ_EN(0), int_bits);
+}
+
+static void cpr_ctl_modify(struct cpr_drv *drv, u32 mask, u32 value)
+{
+	cpr_masked_write(drv, REG_RBCPR_CTL, mask, value);
+}
+
+static void cpr_ctl_enable(struct cpr_drv *drv, struct corner *corner)
+{
+	u32 val, mask;
+	const struct cpr_desc *desc = drv->desc;
+
+	/* Program Consecutive Up & Down */
+	val = desc->timer_cons_down << RBIF_TIMER_ADJ_CONS_DOWN_SHIFT;
+	val |= desc->timer_cons_up << RBIF_TIMER_ADJ_CONS_UP_SHIFT;
+	mask = RBIF_TIMER_ADJ_CONS_UP_MASK | RBIF_TIMER_ADJ_CONS_DOWN_MASK;
+	cpr_masked_write(drv, REG_RBIF_TIMER_ADJUST, mask, val);
+	cpr_masked_write(drv, REG_RBCPR_CTL,
+			 RBCPR_CTL_SW_AUTO_CONT_NACK_DN_EN |
+			 RBCPR_CTL_SW_AUTO_CONT_ACK_EN,
+			 corner->save_ctl);
+	cpr_irq_set(drv, corner->save_irq);
+
+	if (cpr_is_allowed(drv) && corner->max_uV > corner->min_uV)
+		val = RBCPR_CTL_LOOP_EN;
+	else
+		val = 0;
+	cpr_ctl_modify(drv, RBCPR_CTL_LOOP_EN, val);
+}
+
+static void cpr_ctl_disable(struct cpr_drv *drv)
+{
+	cpr_irq_set(drv, 0);
+	cpr_ctl_modify(drv, RBCPR_CTL_SW_AUTO_CONT_NACK_DN_EN |
+		       RBCPR_CTL_SW_AUTO_CONT_ACK_EN, 0);
+	cpr_masked_write(drv, REG_RBIF_TIMER_ADJUST,
+			 RBIF_TIMER_ADJ_CONS_UP_MASK |
+			 RBIF_TIMER_ADJ_CONS_DOWN_MASK, 0);
+	cpr_irq_clr(drv);
+	cpr_write(drv, REG_RBIF_CONT_ACK_CMD, 1);
+	cpr_write(drv, REG_RBIF_CONT_NACK_CMD, 1);
+	cpr_ctl_modify(drv, RBCPR_CTL_LOOP_EN, 0);
+}
+
+static bool cpr_ctl_is_enabled(struct cpr_drv *drv)
+{
+	u32 reg_val;
+
+	reg_val = cpr_read(drv, REG_RBCPR_CTL);
+	return reg_val & RBCPR_CTL_LOOP_EN;
+}
+
+static bool cpr_ctl_is_busy(struct cpr_drv *drv)
+{
+	u32 reg_val;
+
+	reg_val = cpr_read(drv, REG_RBCPR_RESULT_0);
+	return reg_val & RBCPR_RESULT0_BUSY_MASK;
+}
+
+static void cpr_corner_save(struct cpr_drv *drv, struct corner *corner)
+{
+	corner->save_ctl = cpr_read(drv, REG_RBCPR_CTL);
+	corner->save_irq = cpr_read(drv, REG_RBIF_IRQ_EN(0));
+}
+
+static void cpr_corner_restore(struct cpr_drv *drv, struct corner *corner)
+{
+	u32 gcnt, ctl, irq, ro_sel, step_quot;
+	struct fuse_corner *fuse = corner->fuse_corner;
+	const struct cpr_desc *desc = drv->desc;
+	int i;
+
+	ro_sel = fuse->ring_osc_idx;
+	gcnt = drv->gcnt;
+	gcnt |= fuse->quot - corner->quot_adjust;
+
+	/* Program the step quotient and idle clocks */
+	step_quot = desc->idle_clocks << RBCPR_STEP_QUOT_IDLE_CLK_SHIFT;
+	step_quot |= fuse->step_quot & RBCPR_STEP_QUOT_STEPQUOT_MASK;
+	cpr_write(drv, REG_RBCPR_STEP_QUOT, step_quot);
+
+	/* Clear the target quotient value and gate count of all ROs */
+	for (i = 0; i < CPR_NUM_RING_OSC; i++)
+		cpr_write(drv, REG_RBCPR_GCNT_TARGET(i), 0);
+
+	cpr_write(drv, REG_RBCPR_GCNT_TARGET(ro_sel), gcnt);
+	ctl = corner->save_ctl;
+	cpr_write(drv, REG_RBCPR_CTL, ctl);
+	irq = corner->save_irq;
+	cpr_irq_set(drv, irq);
+	dev_dbg(drv->dev, "gcnt = %#08x, ctl = %#08x, irq = %#08x\n", gcnt,
+		ctl, irq);
+}
+
+static void cpr_set_acc(struct regmap *tcsr, struct fuse_corner *f,
+			struct fuse_corner *end)
+{
+	if (f == end)
+		return;
+
+	if (f < end) {
+		for (f += 1; f <= end; f++)
+			regmap_multi_reg_write(tcsr, f->accs, f->num_accs);
+	} else {
+		for (f -= 1; f >= end; f--)
+			regmap_multi_reg_write(tcsr, f->accs, f->num_accs);
+	}
+}
+
+static int cpr_pre_voltage(struct cpr_drv *drv,
+			   struct fuse_corner *fuse_corner,
+			   enum voltage_change_dir dir)
+{
+	struct fuse_corner *prev_fuse_corner = drv->corner->fuse_corner;
+
+	if (drv->tcsr && dir == DOWN)
+		cpr_set_acc(drv->tcsr, prev_fuse_corner, fuse_corner);
+
+	return 0;
+}
+
+static int cpr_post_voltage(struct cpr_drv *drv,
+			    struct fuse_corner *fuse_corner,
+			    enum voltage_change_dir dir)
+{
+	struct fuse_corner *prev_fuse_corner = drv->corner->fuse_corner;
+
+	if (drv->tcsr && dir == UP)
+		cpr_set_acc(drv->tcsr, prev_fuse_corner, fuse_corner);
+
+	return 0;
+}
+
+static int cpr_scale_voltage(struct cpr_drv *drv, struct corner *corner,
+			     int new_uV, enum voltage_change_dir dir)
+{
+	int ret;
+	struct fuse_corner *fuse_corner = corner->fuse_corner;
+
+	ret = cpr_pre_voltage(drv, fuse_corner, dir);
+	if (ret)
+		return ret;
+
+	ret = regulator_set_voltage(drv->vdd_apc, new_uV, new_uV);
+	if (ret) {
+		dev_err_ratelimited(drv->dev, "failed to set apc voltage %d\n",
+				    new_uV);
+		return ret;
+	}
+
+	ret = cpr_post_voltage(drv, fuse_corner, dir);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static unsigned int cpr_get_cur_perf_state(struct cpr_drv *drv)
+{
+	return drv->corner ? drv->corner - drv->corners + 1 : 0;
+}
+
+static int cpr_scale(struct cpr_drv *drv, enum voltage_change_dir dir)
+{
+	u32 val, error_steps, reg_mask;
+	int last_uV, new_uV, step_uV, ret;
+	struct corner *corner;
+	const struct cpr_desc *desc = drv->desc;
+
+	if (dir != UP && dir != DOWN)
+		return 0;
+
+	step_uV = regulator_get_linear_step(drv->vdd_apc);
+	if (!step_uV)
+		return -EINVAL;
+
+	corner = drv->corner;
+
+	val = cpr_read(drv, REG_RBCPR_RESULT_0);
+
+	error_steps = val >> RBCPR_RESULT0_ERROR_STEPS_SHIFT;
+	error_steps &= RBCPR_RESULT0_ERROR_STEPS_MASK;
+	last_uV = corner->last_uV;
+
+	if (dir == UP) {
+		if (desc->clamp_timer_interval &&
+		    error_steps < desc->up_threshold) {
+			/*
+			 * Handle the case where another measurement started
+			 * after the interrupt was triggered due to a core
+			 * exiting from power collapse.
+			 */
+			error_steps = max(desc->up_threshold,
+					  desc->vdd_apc_step_up_limit);
+		}
+
+		if (last_uV >= corner->max_uV) {
+			cpr_irq_clr_nack(drv);
+
+			/* Maximize the UP threshold */
+			reg_mask = RBCPR_CTL_UP_THRESHOLD_MASK;
+			reg_mask <<= RBCPR_CTL_UP_THRESHOLD_SHIFT;
+			val = reg_mask;
+			cpr_ctl_modify(drv, reg_mask, val);
+
+			/* Disable UP interrupt */
+			cpr_irq_set(drv, CPR_INT_DEFAULT & ~CPR_INT_UP);
+
+			return 0;
+		}
+
+		if (error_steps > desc->vdd_apc_step_up_limit)
+			error_steps = desc->vdd_apc_step_up_limit;
+
+		/* Calculate new voltage */
+		new_uV = last_uV + error_steps * step_uV;
+		new_uV = min(new_uV, corner->max_uV);
+
+		dev_dbg(drv->dev,
+			"UP: -> new_uV: %d last_uV: %d perf state: %u\n",
+			new_uV, last_uV, cpr_get_cur_perf_state(drv));
+	} else {
+		if (desc->clamp_timer_interval &&
+		    error_steps < desc->down_threshold) {
+			/*
+			 * Handle the case where another measurement started
+			 * after the interrupt was triggered due to a core
+			 * exiting from power collapse.
+			 */
+			error_steps = max(desc->down_threshold,
+					  desc->vdd_apc_step_down_limit);
+		}
+
+		if (last_uV <= corner->min_uV) {
+			cpr_irq_clr_nack(drv);
+
+			/* Enable auto nack down */
+			reg_mask = RBCPR_CTL_SW_AUTO_CONT_NACK_DN_EN;
+			val = RBCPR_CTL_SW_AUTO_CONT_NACK_DN_EN;
+
+			cpr_ctl_modify(drv, reg_mask, val);
+
+			/* Disable DOWN interrupt */
+			cpr_irq_set(drv, CPR_INT_DEFAULT & ~CPR_INT_DOWN);
+
+			return 0;
+		}
+
+		if (error_steps > desc->vdd_apc_step_down_limit)
+			error_steps = desc->vdd_apc_step_down_limit;
+
+		/* Calculate new voltage */
+		new_uV = last_uV - error_steps * step_uV;
+		new_uV = max(new_uV, corner->min_uV);
+
+		dev_dbg(drv->dev,
+			"DOWN: -> new_uV: %d last_uV: %d perf state: %u\n",
+			new_uV, last_uV, cpr_get_cur_perf_state(drv));
+	}
+
+	ret = cpr_scale_voltage(drv, corner, new_uV, dir);
+	if (ret) {
+		cpr_irq_clr_nack(drv);
+		return ret;
+	}
+	drv->corner->last_uV = new_uV;
+
+	if (dir == UP) {
+		/* Disable auto nack down */
+		reg_mask = RBCPR_CTL_SW_AUTO_CONT_NACK_DN_EN;
+		val = 0;
+	} else {
+		/* Restore default threshold for UP */
+		reg_mask = RBCPR_CTL_UP_THRESHOLD_MASK;
+		reg_mask <<= RBCPR_CTL_UP_THRESHOLD_SHIFT;
+		val = desc->up_threshold;
+		val <<= RBCPR_CTL_UP_THRESHOLD_SHIFT;
+	}
+
+	cpr_ctl_modify(drv, reg_mask, val);
+
+	/* Re-enable default interrupts */
+	cpr_irq_set(drv, CPR_INT_DEFAULT);
+
+	/* Ack */
+	cpr_irq_clr_ack(drv);
+
+	return 0;
+}
+
+static irqreturn_t cpr_irq_handler(int irq, void *dev)
+{
+	struct cpr_drv *drv = dev;
+	const struct cpr_desc *desc = drv->desc;
+	irqreturn_t ret = IRQ_HANDLED;
+	u32 val;
+
+	mutex_lock(&drv->lock);
+
+	val = cpr_read(drv, REG_RBIF_IRQ_STATUS);
+	if (drv->flags & FLAGS_IGNORE_1ST_IRQ_STATUS)
+		val = cpr_read(drv, REG_RBIF_IRQ_STATUS);
+
+	dev_dbg(drv->dev, "IRQ_STATUS = %#02x\n", val);
+
+	if (!cpr_ctl_is_enabled(drv)) {
+		dev_dbg(drv->dev, "CPR is disabled\n");
+		ret = IRQ_NONE;
+	} else if (cpr_ctl_is_busy(drv) && !desc->clamp_timer_interval) {
+		dev_dbg(drv->dev, "CPR measurement is not ready\n");
+	} else if (!cpr_is_allowed(drv)) {
+		val = cpr_read(drv, REG_RBCPR_CTL);
+		dev_err_ratelimited(drv->dev,
+				    "Interrupt broken? RBCPR_CTL = %#02x\n",
+				    val);
+		ret = IRQ_NONE;
+	} else {
+		/*
+		 * Following sequence of handling is as per each IRQ's
+		 * priority
+		 */
+		if (val & CPR_INT_UP) {
+			cpr_scale(drv, UP);
+		} else if (val & CPR_INT_DOWN) {
+			cpr_scale(drv, DOWN);
+		} else if (val & CPR_INT_MIN) {
+			cpr_irq_clr_nack(drv);
+		} else if (val & CPR_INT_MAX) {
+			cpr_irq_clr_nack(drv);
+		} else if (val & CPR_INT_MID) {
+			/* RBCPR_CTL_SW_AUTO_CONT_ACK_EN is enabled */
+			dev_dbg(drv->dev, "IRQ occurred for Mid Flag\n");
+		} else {
+			dev_dbg(drv->dev,
+				"IRQ occurred for unknown flag (%#08x)\n", val);
+		}
+
+		/* Save register values for the corner */
+		cpr_corner_save(drv, drv->corner);
+	}
+
+	mutex_unlock(&drv->lock);
+
+	return ret;
+}
+
+static int cpr_enable(struct cpr_drv *drv)
+{
+	int ret;
+
+	ret = regulator_enable(drv->vdd_apc);
+	if (ret)
+		return ret;
+
+	mutex_lock(&drv->lock);
+
+	if (cpr_is_allowed(drv) && drv->corner) {
+		cpr_irq_clr(drv);
+		cpr_corner_restore(drv, drv->corner);
+		cpr_ctl_enable(drv, drv->corner);
+	}
+
+	mutex_unlock(&drv->lock);
+
+	return 0;
+}
+
+static int cpr_disable(struct cpr_drv *drv)
+{
+	mutex_lock(&drv->lock);
+
+	if (cpr_is_allowed(drv)) {
+		cpr_ctl_disable(drv);
+		cpr_irq_clr(drv);
+	}
+
+	mutex_unlock(&drv->lock);
+
+	return regulator_disable(drv->vdd_apc);
+}
+
+static int cpr_config(struct cpr_drv *drv)
+{
+	int i;
+	u32 val, gcnt;
+	struct corner *corner;
+	const struct cpr_desc *desc = drv->desc;
+
+	/* Disable interrupt and CPR */
+	cpr_write(drv, REG_RBIF_IRQ_EN(0), 0);
+	cpr_write(drv, REG_RBCPR_CTL, 0);
+
+	/* Program the default HW ceiling, floor and vlevel */
+	val = (RBIF_LIMIT_CEILING_DEFAULT & RBIF_LIMIT_CEILING_MASK)
+		<< RBIF_LIMIT_CEILING_SHIFT;
+	val |= RBIF_LIMIT_FLOOR_DEFAULT & RBIF_LIMIT_FLOOR_MASK;
+	cpr_write(drv, REG_RBIF_LIMIT, val);
+	cpr_write(drv, REG_RBIF_SW_VLEVEL, RBIF_SW_VLEVEL_DEFAULT);
+
+	/*
+	 * Clear the target quotient value and gate count of all
+	 * ring oscillators
+	 */
+	for (i = 0; i < CPR_NUM_RING_OSC; i++)
+		cpr_write(drv, REG_RBCPR_GCNT_TARGET(i), 0);
+
+	/* Init and save gcnt */
+	gcnt = (drv->ref_clk_khz * desc->gcnt_us) / 1000;
+	gcnt = gcnt & RBCPR_GCNT_TARGET_GCNT_MASK;
+	gcnt <<= RBCPR_GCNT_TARGET_GCNT_SHIFT;
+	drv->gcnt = gcnt;
+
+	/* Program the delay count for the timer */
+	val = (drv->ref_clk_khz * desc->timer_delay_us) / 1000;
+	cpr_write(drv, REG_RBCPR_TIMER_INTERVAL, val);
+	dev_dbg(drv->dev, "Timer count: %#0x (for %d us)\n", val,
+		desc->timer_delay_us);
+
+	/* Program Consecutive Up & Down */
+	val = desc->timer_cons_down << RBIF_TIMER_ADJ_CONS_DOWN_SHIFT;
+	val |= desc->timer_cons_up << RBIF_TIMER_ADJ_CONS_UP_SHIFT;
+	val |= desc->clamp_timer_interval << RBIF_TIMER_ADJ_CLAMP_INT_SHIFT;
+	cpr_write(drv, REG_RBIF_TIMER_ADJUST, val);
+
+	/* Program the control register */
+	val = desc->up_threshold << RBCPR_CTL_UP_THRESHOLD_SHIFT;
+	val |= desc->down_threshold << RBCPR_CTL_DN_THRESHOLD_SHIFT;
+	val |= RBCPR_CTL_TIMER_EN | RBCPR_CTL_COUNT_MODE;
+	val |= RBCPR_CTL_SW_AUTO_CONT_ACK_EN;
+	cpr_write(drv, REG_RBCPR_CTL, val);
+
+	for (i = 0; i < drv->num_corners; i++) {
+		corner = &drv->corners[i];
+		corner->save_ctl = val;
+		corner->save_irq = CPR_INT_DEFAULT;
+	}
+
+	cpr_irq_set(drv, CPR_INT_DEFAULT);
+
+	val = cpr_read(drv, REG_RBCPR_VERSION);
+	if (val <= RBCPR_VER_2)
+		drv->flags |= FLAGS_IGNORE_1ST_IRQ_STATUS;
+
+	return 0;
+}
+
+static int cpr_set_performance_state(struct generic_pm_domain *domain,
+				     unsigned int state)
+{
+	struct cpr_drv *drv = container_of(domain, struct cpr_drv, pd);
+	struct corner *corner, *end;
+	enum voltage_change_dir dir;
+	int ret = 0, new_uV;
+
+	mutex_lock(&drv->lock);
+
+	dev_dbg(drv->dev, "%s: setting perf state: %u (prev state: %u)\n",
+		__func__, state, cpr_get_cur_perf_state(drv));
+
+	/*
+	 * Determine new corner we're going to.
+	 * Remove one since lowest performance state is 1.
+	 */
+	corner = drv->corners + state - 1;
+	end = &drv->corners[drv->num_corners - 1];
+	if (corner > end || corner < drv->corners) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	/* Determine direction */
+	if (drv->corner > corner)
+		dir = DOWN;
+	else if (drv->corner < corner)
+		dir = UP;
+	else
+		dir = NO_CHANGE;
+
+	if (cpr_is_allowed(drv))
+		new_uV = corner->last_uV;
+	else
+		new_uV = corner->uV;
+
+	if (cpr_is_allowed(drv))
+		cpr_ctl_disable(drv);
+
+	ret = cpr_scale_voltage(drv, corner, new_uV, dir);
+	if (ret)
+		goto unlock;
+
+	if (cpr_is_allowed(drv)) {
+		cpr_irq_clr(drv);
+		if (drv->corner != corner)
+			cpr_corner_restore(drv, corner);
+		cpr_ctl_enable(drv, corner);
+	}
+
+	drv->corner = corner;
+
+unlock:
+	mutex_unlock(&drv->lock);
+
+	return ret;
+}
+
+static int cpr_read_efuse(struct device *dev, const char *cname, u32 *data)
+{
+	struct nvmem_cell *cell;
+	ssize_t len;
+	char *ret;
+	int i;
+
+	*data = 0;
+
+	cell = nvmem_cell_get(dev, cname);
+	if (IS_ERR(cell)) {
+		if (PTR_ERR(cell) != -EPROBE_DEFER)
+			dev_err(dev, "undefined cell %s\n", cname);
+		return PTR_ERR(cell);
+	}
+
+	ret = nvmem_cell_read(cell, &len);
+	nvmem_cell_put(cell);
+	if (IS_ERR(ret)) {
+		dev_err(dev, "can't read cell %s\n", cname);
+		return PTR_ERR(ret);
+	}
+
+	for (i = 0; i < len; i++)
+		*data |= ret[i] << (8 * i);
+
+	kfree(ret);
+	dev_dbg(dev, "efuse read(%s) = %x, bytes %zd\n", cname, *data, len);
+
+	return 0;
+}
+
+static int
+cpr_populate_ring_osc_idx(struct cpr_drv *drv)
+{
+	struct fuse_corner *fuse = drv->fuse_corners;
+	struct fuse_corner *end = fuse + drv->desc->num_fuse_corners;
+	const struct cpr_fuse *fuses = drv->cpr_fuses;
+	u32 data;
+	int ret;
+
+	for (; fuse < end; fuse++, fuses++) {
+		ret = cpr_read_efuse(drv->dev, fuses->ring_osc,
+				     &data);
+		if (ret)
+			return ret;
+		fuse->ring_osc_idx = data;
+	}
+
+	return 0;
+}
+
+static int cpr_read_fuse_uV(const struct cpr_desc *desc,
+			    const struct fuse_corner_data *fdata,
+			    const char *init_v_efuse,
+			    int step_volt,
+			    struct cpr_drv *drv)
+{
+	int step_size_uV, steps, uV;
+	u32 bits = 0;
+	int ret;
+
+	ret = cpr_read_efuse(drv->dev, init_v_efuse, &bits);
+	if (ret)
+		return ret;
+
+	steps = bits & ~BIT(desc->cpr_fuses.init_voltage_width - 1);
+	/* Not two's complement.. instead highest bit is sign bit */
+	if (bits & BIT(desc->cpr_fuses.init_voltage_width - 1))
+		steps = -steps;
+
+	step_size_uV = desc->cpr_fuses.init_voltage_step;
+
+	uV = fdata->ref_uV + steps * step_size_uV;
+	return DIV_ROUND_UP(uV, step_volt) * step_volt;
+}
+
+static int cpr_fuse_corner_init(struct cpr_drv *drv)
+{
+	const struct cpr_desc *desc = drv->desc;
+	const struct cpr_fuse *fuses = drv->cpr_fuses;
+	const struct acc_desc *acc_desc = drv->acc_desc;
+	int i;
+	unsigned int step_volt;
+	struct fuse_corner_data *fdata;
+	struct fuse_corner *fuse, *end;
+	int uV;
+	const struct reg_sequence *accs;
+	int ret;
+
+	accs = acc_desc->settings;
+
+	step_volt = regulator_get_linear_step(drv->vdd_apc);
+	if (!step_volt)
+		return -EINVAL;
+
+	/* Populate fuse_corner members */
+	fuse = drv->fuse_corners;
+	end = &fuse[desc->num_fuse_corners - 1];
+	fdata = desc->cpr_fuses.fuse_corner_data;
+
+	for (i = 0; fuse <= end; fuse++, fuses++, i++, fdata++) {
+		/*
+		 * Update SoC voltages: platforms might choose a different
+		 * regulators than the one used to characterize the algorithms
+		 * (ie, init_voltage_step).
+		 */
+		fdata->min_uV = roundup(fdata->min_uV, step_volt);
+		fdata->max_uV = roundup(fdata->max_uV, step_volt);
+
+		/* Populate uV */
+		uV = cpr_read_fuse_uV(desc, fdata, fuses->init_voltage,
+				      step_volt, drv);
+		if (uV < 0)
+			return uV;
+
+		fuse->min_uV = fdata->min_uV;
+		fuse->max_uV = fdata->max_uV;
+		fuse->uV = clamp(uV, fuse->min_uV, fuse->max_uV);
+
+		if (fuse == end) {
+			/*
+			 * Allow the highest fuse corner's PVS voltage to
+			 * define the ceiling voltage for that corner in order
+			 * to support SoC's in which variable ceiling values
+			 * are required.
+			 */
+			end->max_uV = max(end->max_uV, end->uV);
+		}
+
+		/* Populate target quotient by scaling */
+		ret = cpr_read_efuse(drv->dev, fuses->quotient, &fuse->quot);
+		if (ret)
+			return ret;
+
+		fuse->quot *= fdata->quot_scale;
+		fuse->quot += fdata->quot_offset;
+		fuse->quot += fdata->quot_adjust;
+		fuse->step_quot = desc->step_quot[fuse->ring_osc_idx];
+
+		/* Populate acc settings */
+		fuse->accs = accs;
+		fuse->num_accs = acc_desc->num_regs_per_fuse;
+		accs += acc_desc->num_regs_per_fuse;
+	}
+
+	/*
+	 * Restrict all fuse corner PVS voltages based upon per corner
+	 * ceiling and floor voltages.
+	 */
+	for (fuse = drv->fuse_corners, i = 0; fuse <= end; fuse++, i++) {
+		if (fuse->uV > fuse->max_uV)
+			fuse->uV = fuse->max_uV;
+		else if (fuse->uV < fuse->min_uV)
+			fuse->uV = fuse->min_uV;
+
+		ret = regulator_is_supported_voltage(drv->vdd_apc,
+						     fuse->min_uV,
+						     fuse->min_uV);
+		if (!ret) {
+			dev_err(drv->dev,
+				"min uV: %d (fuse corner: %d) not supported by regulator\n",
+				fuse->min_uV, i);
+			return -EINVAL;
+		}
+
+		ret = regulator_is_supported_voltage(drv->vdd_apc,
+						     fuse->max_uV,
+						     fuse->max_uV);
+		if (!ret) {
+			dev_err(drv->dev,
+				"max uV: %d (fuse corner: %d) not supported by regulator\n",
+				fuse->max_uV, i);
+			return -EINVAL;
+		}
+
+		dev_dbg(drv->dev,
+			"fuse corner %d: [%d %d %d] RO%hhu quot %d squot %d\n",
+			i, fuse->min_uV, fuse->uV, fuse->max_uV,
+			fuse->ring_osc_idx, fuse->quot, fuse->step_quot);
+	}
+
+	return 0;
+}
+
+static int cpr_calculate_scaling(const char *quot_offset,
+				 struct cpr_drv *drv,
+				 const struct fuse_corner_data *fdata,
+				 const struct corner *corner)
+{
+	u32 quot_diff = 0;
+	unsigned long freq_diff;
+	int scaling;
+	const struct fuse_corner *fuse, *prev_fuse;
+	int ret;
+
+	fuse = corner->fuse_corner;
+	prev_fuse = fuse - 1;
+
+	if (quot_offset) {
+		ret = cpr_read_efuse(drv->dev, quot_offset, &quot_diff);
+		if (ret)
+			return ret;
+
+		quot_diff *= fdata->quot_offset_scale;
+		quot_diff += fdata->quot_offset_adjust;
+	} else {
+		quot_diff = fuse->quot - prev_fuse->quot;
+	}
+
+	freq_diff = fuse->max_freq - prev_fuse->max_freq;
+	freq_diff /= 1000000; /* Convert to MHz */
+	scaling = 1000 * quot_diff / freq_diff;
+	return min(scaling, fdata->max_quot_scale);
+}
+
+static int cpr_interpolate(const struct corner *corner, int step_volt,
+			   const struct fuse_corner_data *fdata)
+{
+	unsigned long f_high, f_low, f_diff;
+	int uV_high, uV_low, uV;
+	u64 temp, temp_limit;
+	const struct fuse_corner *fuse, *prev_fuse;
+
+	fuse = corner->fuse_corner;
+	prev_fuse = fuse - 1;
+
+	f_high = fuse->max_freq;
+	f_low = prev_fuse->max_freq;
+	uV_high = fuse->uV;
+	uV_low = prev_fuse->uV;
+	f_diff = fuse->max_freq - corner->freq;
+
+	/*
+	 * Don't interpolate in the wrong direction. This could happen
+	 * if the adjusted fuse voltage overlaps with the previous fuse's
+	 * adjusted voltage.
+	 */
+	if (f_high <= f_low || uV_high <= uV_low || f_high <= corner->freq)
+		return corner->uV;
+
+	temp = f_diff * (uV_high - uV_low);
+	do_div(temp, f_high - f_low);
+
+	/*
+	 * max_volt_scale has units of uV/MHz while freq values
+	 * have units of Hz.  Divide by 1000000 to convert to.
+	 */
+	temp_limit = f_diff * fdata->max_volt_scale;
+	do_div(temp_limit, 1000000);
+
+	uV = uV_high - min(temp, temp_limit);
+	return roundup(uV, step_volt);
+}
+
+static unsigned int cpr_get_fuse_corner(struct dev_pm_opp *opp)
+{
+	struct device_node *np;
+	unsigned int fuse_corner = 0;
+
+	np = dev_pm_opp_get_of_node(opp);
+	if (of_property_read_u32(np, "qcom,opp-fuse-level", &fuse_corner))
+		pr_err("%s: missing 'qcom,opp-fuse-level' property\n",
+		       __func__);
+
+	of_node_put(np);
+
+	return fuse_corner;
+}
+
+static unsigned long cpr_get_opp_hz_for_req(struct dev_pm_opp *ref,
+					    struct device *cpu_dev)
+{
+	u64 rate = 0;
+	struct device_node *ref_np;
+	struct device_node *desc_np;
+	struct device_node *child_np = NULL;
+	struct device_node *child_req_np = NULL;
+
+	desc_np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+	if (!desc_np)
+		return 0;
+
+	ref_np = dev_pm_opp_get_of_node(ref);
+	if (!ref_np)
+		goto out_ref;
+
+	do {
+		of_node_put(child_req_np);
+		child_np = of_get_next_available_child(desc_np, child_np);
+		child_req_np = of_parse_phandle(child_np, "required-opps", 0);
+	} while (child_np && child_req_np != ref_np);
+
+	if (child_np && child_req_np == ref_np)
+		of_property_read_u64(child_np, "opp-hz", &rate);
+
+	of_node_put(child_req_np);
+	of_node_put(child_np);
+	of_node_put(ref_np);
+out_ref:
+	of_node_put(desc_np);
+
+	return (unsigned long) rate;
+}
+
+static int cpr_corner_init(struct cpr_drv *drv)
+{
+	const struct cpr_desc *desc = drv->desc;
+	const struct cpr_fuse *fuses = drv->cpr_fuses;
+	int i, level, scaling = 0;
+	unsigned int fnum, fc;
+	const char *quot_offset;
+	struct fuse_corner *fuse, *prev_fuse;
+	struct corner *corner, *end;
+	struct corner_data *cdata;
+	const struct fuse_corner_data *fdata;
+	bool apply_scaling;
+	unsigned long freq_diff, freq_diff_mhz;
+	unsigned long freq;
+	int step_volt = regulator_get_linear_step(drv->vdd_apc);
+	struct dev_pm_opp *opp;
+
+	if (!step_volt)
+		return -EINVAL;
+
+	corner = drv->corners;
+	end = &corner[drv->num_corners - 1];
+
+	cdata = devm_kcalloc(drv->dev, drv->num_corners,
+			     sizeof(struct corner_data),
+			     GFP_KERNEL);
+	if (!cdata)
+		return -ENOMEM;
+
+	/*
+	 * Store maximum frequency for each fuse corner based on the frequency
+	 * plan
+	 */
+	for (level = 1; level <= drv->num_corners; level++) {
+		opp = dev_pm_opp_find_level_exact(&drv->pd.dev, level);
+		if (IS_ERR(opp))
+			return -EINVAL;
+		fc = cpr_get_fuse_corner(opp);
+		if (!fc) {
+			dev_pm_opp_put(opp);
+			return -EINVAL;
+		}
+		fnum = fc - 1;
+		freq = cpr_get_opp_hz_for_req(opp, drv->attached_cpu_dev);
+		if (!freq) {
+			dev_pm_opp_put(opp);
+			return -EINVAL;
+		}
+		cdata[level - 1].fuse_corner = fnum;
+		cdata[level - 1].freq = freq;
+
+		fuse = &drv->fuse_corners[fnum];
+		dev_dbg(drv->dev, "freq: %lu level: %u fuse level: %u\n",
+			freq, dev_pm_opp_get_level(opp) - 1, fnum);
+		if (freq > fuse->max_freq)
+			fuse->max_freq = freq;
+		dev_pm_opp_put(opp);
+	}
+
+	/*
+	 * Get the quotient adjustment scaling factor, according to:
+	 *
+	 * scaling = min(1000 * (QUOT(corner_N) - QUOT(corner_N-1))
+	 *		/ (freq(corner_N) - freq(corner_N-1)), max_factor)
+	 *
+	 * QUOT(corner_N):	quotient read from fuse for fuse corner N
+	 * QUOT(corner_N-1):	quotient read from fuse for fuse corner (N - 1)
+	 * freq(corner_N):	max frequency in MHz supported by fuse corner N
+	 * freq(corner_N-1):	max frequency in MHz supported by fuse corner
+	 *			 (N - 1)
+	 *
+	 * Then walk through the corners mapped to each fuse corner
+	 * and calculate the quotient adjustment for each one using the
+	 * following formula:
+	 *
+	 * quot_adjust = (freq_max - freq_corner) * scaling / 1000
+	 *
+	 * freq_max: max frequency in MHz supported by the fuse corner
+	 * freq_corner: frequency in MHz corresponding to the corner
+	 * scaling: calculated from above equation
+	 *
+	 *
+	 *     +                           +
+	 *     |                         v |
+	 *   q |           f c           o |           f c
+	 *   u |         c               l |         c
+	 *   o |       f                 t |       f
+	 *   t |     c                   a |     c
+	 *     | c f                     g | c f
+	 *     |                         e |
+	 *     +---------------            +----------------
+	 *       0 1 2 3 4 5 6               0 1 2 3 4 5 6
+	 *          corner                      corner
+	 *
+	 *    c = corner
+	 *    f = fuse corner
+	 *
+	 */
+	for (apply_scaling = false, i = 0; corner <= end; corner++, i++) {
+		fnum = cdata[i].fuse_corner;
+		fdata = &desc->cpr_fuses.fuse_corner_data[fnum];
+		quot_offset = fuses[fnum].quotient_offset;
+		fuse = &drv->fuse_corners[fnum];
+		if (fnum)
+			prev_fuse = &drv->fuse_corners[fnum - 1];
+		else
+			prev_fuse = NULL;
+
+		corner->fuse_corner = fuse;
+		corner->freq = cdata[i].freq;
+		corner->uV = fuse->uV;
+
+		if (prev_fuse && cdata[i - 1].freq == prev_fuse->max_freq) {
+			scaling = cpr_calculate_scaling(quot_offset, drv,
+							fdata, corner);
+			if (scaling < 0)
+				return scaling;
+
+			apply_scaling = true;
+		} else if (corner->freq == fuse->max_freq) {
+			/* This is a fuse corner; don't scale anything */
+			apply_scaling = false;
+		}
+
+		if (apply_scaling) {
+			freq_diff = fuse->max_freq - corner->freq;
+			freq_diff_mhz = freq_diff / 1000000;
+			corner->quot_adjust = scaling * freq_diff_mhz / 1000;
+
+			corner->uV = cpr_interpolate(corner, step_volt, fdata);
+		}
+
+		corner->max_uV = fuse->max_uV;
+		corner->min_uV = fuse->min_uV;
+		corner->uV = clamp(corner->uV, corner->min_uV, corner->max_uV);
+		corner->last_uV = corner->uV;
+
+		/* Reduce the ceiling voltage if needed */
+		if (desc->reduce_to_corner_uV && corner->uV < corner->max_uV)
+			corner->max_uV = corner->uV;
+		else if (desc->reduce_to_fuse_uV && fuse->uV < corner->max_uV)
+			corner->max_uV = max(corner->min_uV, fuse->uV);
+
+		dev_dbg(drv->dev, "corner %d: [%d %d %d] quot %d\n", i,
+			corner->min_uV, corner->uV, corner->max_uV,
+			fuse->quot - corner->quot_adjust);
+	}
+
+	return 0;
+}
+
+static const struct cpr_fuse *cpr_get_fuses(struct cpr_drv *drv)
+{
+	const struct cpr_desc *desc = drv->desc;
+	struct cpr_fuse *fuses;
+	int i;
+
+	fuses = devm_kcalloc(drv->dev, desc->num_fuse_corners,
+			     sizeof(struct cpr_fuse),
+			     GFP_KERNEL);
+	if (!fuses)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < desc->num_fuse_corners; i++) {
+		char tbuf[32];
+
+		snprintf(tbuf, 32, "cpr_ring_osc%d", i + 1);
+		fuses[i].ring_osc = devm_kstrdup(drv->dev, tbuf, GFP_KERNEL);
+		if (!fuses[i].ring_osc)
+			return ERR_PTR(-ENOMEM);
+
+		snprintf(tbuf, 32, "cpr_init_voltage%d", i + 1);
+		fuses[i].init_voltage = devm_kstrdup(drv->dev, tbuf,
+						     GFP_KERNEL);
+		if (!fuses[i].init_voltage)
+			return ERR_PTR(-ENOMEM);
+
+		snprintf(tbuf, 32, "cpr_quotient%d", i + 1);
+		fuses[i].quotient = devm_kstrdup(drv->dev, tbuf, GFP_KERNEL);
+		if (!fuses[i].quotient)
+			return ERR_PTR(-ENOMEM);
+
+		snprintf(tbuf, 32, "cpr_quotient_offset%d", i + 1);
+		fuses[i].quotient_offset = devm_kstrdup(drv->dev, tbuf,
+							GFP_KERNEL);
+		if (!fuses[i].quotient_offset)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	return fuses;
+}
+
+static void cpr_set_loop_allowed(struct cpr_drv *drv)
+{
+	drv->loop_disabled = false;
+}
+
+static int cpr_init_parameters(struct cpr_drv *drv)
+{
+	const struct cpr_desc *desc = drv->desc;
+	struct clk *clk;
+
+	clk = clk_get(drv->dev, "ref");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	drv->ref_clk_khz = clk_get_rate(clk) / 1000;
+	clk_put(clk);
+
+	if (desc->timer_cons_up > RBIF_TIMER_ADJ_CONS_UP_MASK ||
+	    desc->timer_cons_down > RBIF_TIMER_ADJ_CONS_DOWN_MASK ||
+	    desc->up_threshold > RBCPR_CTL_UP_THRESHOLD_MASK ||
+	    desc->down_threshold > RBCPR_CTL_DN_THRESHOLD_MASK ||
+	    desc->idle_clocks > RBCPR_STEP_QUOT_IDLE_CLK_MASK ||
+	    desc->clamp_timer_interval > RBIF_TIMER_ADJ_CLAMP_INT_MASK)
+		return -EINVAL;
+
+	dev_dbg(drv->dev, "up threshold = %u, down threshold = %u\n",
+		desc->up_threshold, desc->down_threshold);
+
+	return 0;
+}
+
+static int cpr_find_initial_corner(struct cpr_drv *drv)
+{
+	unsigned long rate;
+	const struct corner *end;
+	struct corner *iter;
+	unsigned int i = 0;
+
+	if (!drv->cpu_clk) {
+		dev_err(drv->dev, "cannot get rate from NULL clk\n");
+		return -EINVAL;
+	}
+
+	end = &drv->corners[drv->num_corners - 1];
+	rate = clk_get_rate(drv->cpu_clk);
+
+	/*
+	 * Some bootloaders set a CPU clock frequency that is not defined
+	 * in the OPP table. When running at an unlisted frequency,
+	 * cpufreq_online() will change to the OPP which has the lowest
+	 * frequency, at or above the unlisted frequency.
+	 * Since cpufreq_online() always "rounds up" in the case of an
+	 * unlisted frequency, this function always "rounds down" in case
+	 * of an unlisted frequency. That way, when cpufreq_online()
+	 * triggers the first ever call to cpr_set_performance_state(),
+	 * it will correctly determine the direction as UP.
+	 */
+	for (iter = drv->corners; iter <= end; iter++) {
+		if (iter->freq > rate)
+			break;
+		i++;
+		if (iter->freq == rate) {
+			drv->corner = iter;
+			break;
+		}
+		if (iter->freq < rate)
+			drv->corner = iter;
+	}
+
+	if (!drv->corner) {
+		dev_err(drv->dev, "boot up corner not found\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(drv->dev, "boot up perf state: %u\n", i);
+
+	return 0;
+}
+
+static const struct cpr_desc qcs404_cpr_desc = {
+	.num_fuse_corners = 3,
+	.min_diff_quot = CPR_FUSE_MIN_QUOT_DIFF,
+	.step_quot = (int []){ 25, 25, 25, },
+	.timer_delay_us = 5000,
+	.timer_cons_up = 0,
+	.timer_cons_down = 2,
+	.up_threshold = 1,
+	.down_threshold = 3,
+	.idle_clocks = 15,
+	.gcnt_us = 1,
+	.vdd_apc_step_up_limit = 1,
+	.vdd_apc_step_down_limit = 1,
+	.cpr_fuses = {
+		.init_voltage_step = 8000,
+		.init_voltage_width = 6,
+		.fuse_corner_data = (struct fuse_corner_data[]){
+			/* fuse corner 0 */
+			{
+				.ref_uV = 1224000,
+				.max_uV = 1224000,
+				.min_uV = 1048000,
+				.max_volt_scale = 0,
+				.max_quot_scale = 0,
+				.quot_offset = 0,
+				.quot_scale = 1,
+				.quot_adjust = 0,
+				.quot_offset_scale = 5,
+				.quot_offset_adjust = 0,
+			},
+			/* fuse corner 1 */
+			{
+				.ref_uV = 1288000,
+				.max_uV = 1288000,
+				.min_uV = 1048000,
+				.max_volt_scale = 2000,
+				.max_quot_scale = 1400,
+				.quot_offset = 0,
+				.quot_scale = 1,
+				.quot_adjust = -20,
+				.quot_offset_scale = 5,
+				.quot_offset_adjust = 0,
+			},
+			/* fuse corner 2 */
+			{
+				.ref_uV = 1352000,
+				.max_uV = 1384000,
+				.min_uV = 1088000,
+				.max_volt_scale = 2000,
+				.max_quot_scale = 1400,
+				.quot_offset = 0,
+				.quot_scale = 1,
+				.quot_adjust = 0,
+				.quot_offset_scale = 5,
+				.quot_offset_adjust = 0,
+			},
+		},
+	},
+};
+
+static const struct acc_desc qcs404_acc_desc = {
+	.settings = (struct reg_sequence[]){
+		{ 0xb120, 0x1041040 },
+		{ 0xb124, 0x41 },
+		{ 0xb120, 0x0 },
+		{ 0xb124, 0x0 },
+		{ 0xb120, 0x0 },
+		{ 0xb124, 0x0 },
+	},
+	.config = (struct reg_sequence[]){
+		{ 0xb138, 0xff },
+		{ 0xb130, 0x5555 },
+	},
+	.num_regs_per_fuse = 2,
+};
+
+static const struct cpr_acc_desc qcs404_cpr_acc_desc = {
+	.cpr_desc = &qcs404_cpr_desc,
+	.acc_desc = &qcs404_acc_desc,
+};
+
+static unsigned int cpr_get_performance_state(struct generic_pm_domain *genpd,
+					      struct dev_pm_opp *opp)
+{
+	return dev_pm_opp_get_level(opp);
+}
+
+static int cpr_power_off(struct generic_pm_domain *domain)
+{
+	struct cpr_drv *drv = container_of(domain, struct cpr_drv, pd);
+
+	return cpr_disable(drv);
+}
+
+static int cpr_power_on(struct generic_pm_domain *domain)
+{
+	struct cpr_drv *drv = container_of(domain, struct cpr_drv, pd);
+
+	return cpr_enable(drv);
+}
+
+static int cpr_pd_attach_dev(struct generic_pm_domain *domain,
+			     struct device *dev)
+{
+	struct cpr_drv *drv = container_of(domain, struct cpr_drv, pd);
+	const struct acc_desc *acc_desc = drv->acc_desc;
+	int ret = 0;
+
+	mutex_lock(&drv->lock);
+
+	dev_dbg(drv->dev, "attach callback for: %s\n", dev_name(dev));
+
+	/*
+	 * This driver only supports scaling voltage for a CPU cluster
+	 * where all CPUs in the cluster share a single regulator.
+	 * Therefore, save the struct device pointer only for the first
+	 * CPU device that gets attached. There is no need to do any
+	 * additional initialization when further CPUs get attached.
+	 */
+	if (drv->attached_cpu_dev)
+		goto unlock;
+
+	/*
+	 * cpr_scale_voltage() requires the direction (if we are changing
+	 * to a higher or lower OPP). The first time
+	 * cpr_set_performance_state() is called, there is no previous
+	 * performance state defined. Therefore, we call
+	 * cpr_find_initial_corner() that gets the CPU clock frequency
+	 * set by the bootloader, so that we can determine the direction
+	 * the first time cpr_set_performance_state() is called.
+	 */
+	drv->cpu_clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(drv->cpu_clk)) {
+		ret = PTR_ERR(drv->cpu_clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(drv->dev, "could not get cpu clk: %d\n", ret);
+		goto unlock;
+	}
+	drv->attached_cpu_dev = dev;
+
+	dev_dbg(drv->dev, "using cpu clk from: %s\n",
+		dev_name(drv->attached_cpu_dev));
+
+	/*
+	 * Everything related to (virtual) corners has to be initialized
+	 * here, when attaching to the power domain, since we need to know
+	 * the maximum frequency for each fuse corner, and this is only
+	 * available after the cpufreq driver has attached to us.
+	 * The reason for this is that we need to know the highest
+	 * frequency associated with each fuse corner.
+	 */
+	ret = dev_pm_opp_get_opp_count(&drv->pd.dev);
+	if (ret < 0) {
+		dev_err(drv->dev, "could not get OPP count\n");
+		goto unlock;
+	}
+	drv->num_corners = ret;
+
+	if (drv->num_corners < 2) {
+		dev_err(drv->dev, "need at least 2 OPPs to use CPR\n");
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	drv->corners = devm_kcalloc(drv->dev, drv->num_corners,
+				    sizeof(*drv->corners),
+				    GFP_KERNEL);
+	if (!drv->corners) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	ret = cpr_corner_init(drv);
+	if (ret)
+		goto unlock;
+
+	cpr_set_loop_allowed(drv);
+
+	ret = cpr_init_parameters(drv);
+	if (ret)
+		goto unlock;
+
+	/* Configure CPR HW but keep it disabled */
+	ret = cpr_config(drv);
+	if (ret)
+		goto unlock;
+
+	ret = cpr_find_initial_corner(drv);
+	if (ret)
+		goto unlock;
+
+	if (acc_desc->config)
+		regmap_multi_reg_write(drv->tcsr, acc_desc->config,
+				       acc_desc->num_regs_per_fuse);
+
+	/* Enable ACC if required */
+	if (acc_desc->enable_mask)
+		regmap_update_bits(drv->tcsr, acc_desc->enable_reg,
+				   acc_desc->enable_mask,
+				   acc_desc->enable_mask);
+
+	dev_info(drv->dev, "driver initialized with %u OPPs\n",
+		 drv->num_corners);
+
+unlock:
+	mutex_unlock(&drv->lock);
+
+	return ret;
+}
+
+static int cpr_debug_info_show(struct seq_file *s, void *unused)
+{
+	u32 gcnt, ro_sel, ctl, irq_status, reg, error_steps;
+	u32 step_dn, step_up, error, error_lt0, busy;
+	struct cpr_drv *drv = s->private;
+	struct fuse_corner *fuse_corner;
+	struct corner *corner;
+
+	corner = drv->corner;
+	fuse_corner = corner->fuse_corner;
+
+	seq_printf(s, "corner, current_volt = %d uV\n",
+		       corner->last_uV);
+
+	ro_sel = fuse_corner->ring_osc_idx;
+	gcnt = cpr_read(drv, REG_RBCPR_GCNT_TARGET(ro_sel));
+	seq_printf(s, "rbcpr_gcnt_target (%u) = %#02X\n", ro_sel, gcnt);
+
+	ctl = cpr_read(drv, REG_RBCPR_CTL);
+	seq_printf(s, "rbcpr_ctl = %#02X\n", ctl);
+
+	irq_status = cpr_read(drv, REG_RBIF_IRQ_STATUS);
+	seq_printf(s, "rbcpr_irq_status = %#02X\n", irq_status);
+
+	reg = cpr_read(drv, REG_RBCPR_RESULT_0);
+	seq_printf(s, "rbcpr_result_0 = %#02X\n", reg);
+
+	step_dn = reg & 0x01;
+	step_up = (reg >> RBCPR_RESULT0_STEP_UP_SHIFT) & 0x01;
+	seq_printf(s, "  [step_dn = %u", step_dn);
+
+	seq_printf(s, ", step_up = %u", step_up);
+
+	error_steps = (reg >> RBCPR_RESULT0_ERROR_STEPS_SHIFT)
+				& RBCPR_RESULT0_ERROR_STEPS_MASK;
+	seq_printf(s, ", error_steps = %u", error_steps);
+
+	error = (reg >> RBCPR_RESULT0_ERROR_SHIFT) & RBCPR_RESULT0_ERROR_MASK;
+	seq_printf(s, ", error = %u", error);
+
+	error_lt0 = (reg >> RBCPR_RESULT0_ERROR_LT0_SHIFT) & 0x01;
+	seq_printf(s, ", error_lt_0 = %u", error_lt0);
+
+	busy = (reg >> RBCPR_RESULT0_BUSY_SHIFT) & 0x01;
+	seq_printf(s, ", busy = %u]\n", busy);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(cpr_debug_info);
+
+static void cpr_debugfs_init(struct cpr_drv *drv)
+{
+	drv->debugfs = debugfs_create_dir("qcom_cpr", NULL);
+
+	debugfs_create_file("debug_info", 0444, drv->debugfs,
+			    drv, &cpr_debug_info_fops);
+}
+
+static int cpr_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	struct cpr_drv *drv;
+	int irq, ret;
+	const struct cpr_acc_desc *data;
+	struct device_node *np;
+	u32 cpr_rev = FUSE_REVISION_UNKNOWN;
+
+	data = of_device_get_match_data(dev);
+	if (!data || !data->cpr_desc || !data->acc_desc)
+		return -EINVAL;
+
+	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+	drv->dev = dev;
+	drv->desc = data->cpr_desc;
+	drv->acc_desc = data->acc_desc;
+
+	drv->fuse_corners = devm_kcalloc(dev, drv->desc->num_fuse_corners,
+					 sizeof(*drv->fuse_corners),
+					 GFP_KERNEL);
+	if (!drv->fuse_corners)
+		return -ENOMEM;
+
+	np = of_parse_phandle(dev->of_node, "acc-syscon", 0);
+	if (!np)
+		return -ENODEV;
+
+	drv->tcsr = syscon_node_to_regmap(np);
+	of_node_put(np);
+	if (IS_ERR(drv->tcsr))
+		return PTR_ERR(drv->tcsr);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	drv->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(drv->base))
+		return PTR_ERR(drv->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -EINVAL;
+
+	drv->vdd_apc = devm_regulator_get(dev, "vdd-apc");
+	if (IS_ERR(drv->vdd_apc))
+		return PTR_ERR(drv->vdd_apc);
+
+	/*
+	 * Initialize fuse corners, since it simply depends
+	 * on data in efuses.
+	 * Everything related to (virtual) corners has to be
+	 * initialized after attaching to the power domain,
+	 * since it depends on the CPU's OPP table.
+	 */
+	ret = cpr_read_efuse(dev, "cpr_fuse_revision", &cpr_rev);
+	if (ret)
+		return ret;
+
+	drv->cpr_fuses = cpr_get_fuses(drv);
+	if (IS_ERR(drv->cpr_fuses))
+		return PTR_ERR(drv->cpr_fuses);
+
+	ret = cpr_populate_ring_osc_idx(drv);
+	if (ret)
+		return ret;
+
+	ret = cpr_fuse_corner_init(drv);
+	if (ret)
+		return ret;
+
+	mutex_init(&drv->lock);
+
+	ret = devm_request_threaded_irq(dev, irq, NULL,
+					cpr_irq_handler,
+					IRQF_ONESHOT | IRQF_TRIGGER_RISING,
+					"cpr", drv);
+	if (ret)
+		return ret;
+
+	drv->pd.name = devm_kstrdup_const(dev, dev->of_node->full_name,
+					  GFP_KERNEL);
+	if (!drv->pd.name)
+		return -EINVAL;
+
+	drv->pd.power_off = cpr_power_off;
+	drv->pd.power_on = cpr_power_on;
+	drv->pd.set_performance_state = cpr_set_performance_state;
+	drv->pd.opp_to_performance_state = cpr_get_performance_state;
+	drv->pd.attach_dev = cpr_pd_attach_dev;
+
+	ret = pm_genpd_init(&drv->pd, NULL, true);
+	if (ret)
+		return ret;
+
+	ret = of_genpd_add_provider_simple(dev->of_node, &drv->pd);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, drv);
+	cpr_debugfs_init(drv);
+
+	return 0;
+}
+
+static int cpr_remove(struct platform_device *pdev)
+{
+	struct cpr_drv *drv = platform_get_drvdata(pdev);
+
+	if (cpr_is_allowed(drv)) {
+		cpr_ctl_disable(drv);
+		cpr_irq_set(drv, 0);
+	}
+
+	of_genpd_del_provider(pdev->dev.of_node);
+	pm_genpd_remove(&drv->pd);
+
+	debugfs_remove_recursive(drv->debugfs);
+
+	return 0;
+}
+
+static const struct of_device_id cpr_match_table[] = {
+	{ .compatible = "qcom,qcs404-cpr", .data = &qcs404_cpr_acc_desc },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, cpr_match_table);
+
+static struct platform_driver cpr_driver = {
+	.probe		= cpr_probe,
+	.remove		= cpr_remove,
+	.driver		= {
+		.name	= "qcom-cpr",
+		.of_match_table = cpr_match_table,
+	},
+};
+module_platform_driver(cpr_driver);
+
+MODULE_DESCRIPTION("Core Power Reduction (CPR) driver");
+MODULE_LICENSE("GPL v2");