drivers/counter/intel-qep.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Intel Quadrature Encoder Peripheral driver
  *
  * Copyright (C) 2019-2021 Intel Corporation
  *
  * Author: Felipe Balbi (Intel)
  * Author: Jarkko Nikula <jarkko.nikula@linux.intel.com>
  * Author: Raymond Tan <raymond.tan@intel.com>
  */
 #include <linux/counter.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/pm_runtime.h>

 #define INTEL_QEPCON			0x00
 #define INTEL_QEPFLT			0x04
 #define INTEL_QEPCOUNT			0x08
 #define INTEL_QEPMAX			0x0c
 #define INTEL_QEPWDT			0x10
 #define INTEL_QEPCAPDIV			0x14
 #define INTEL_QEPCNTR			0x18
 #define INTEL_QEPCAPBUF			0x1c
 #define INTEL_QEPINT_STAT		0x20
 #define INTEL_QEPINT_MASK		0x24

 /* QEPCON */
 #define INTEL_QEPCON_EN			BIT(0)
 #define INTEL_QEPCON_FLT_EN		BIT(1)
 #define INTEL_QEPCON_EDGE_A		BIT(2)
 #define INTEL_QEPCON_EDGE_B		BIT(3)
 #define INTEL_QEPCON_EDGE_INDX		BIT(4)
 #define INTEL_QEPCON_SWPAB		BIT(5)
 #define INTEL_QEPCON_OP_MODE		BIT(6)
 #define INTEL_QEPCON_PH_ERR		BIT(7)
 #define INTEL_QEPCON_COUNT_RST_MODE	BIT(8)
 #define INTEL_QEPCON_INDX_GATING_MASK	GENMASK(10, 9)
 #define INTEL_QEPCON_INDX_GATING(n)	(((n) & 3) << 9)
 #define INTEL_QEPCON_INDX_PAL_PBL	INTEL_QEPCON_INDX_GATING(0)
 #define INTEL_QEPCON_INDX_PAL_PBH	INTEL_QEPCON_INDX_GATING(1)
 #define INTEL_QEPCON_INDX_PAH_PBL	INTEL_QEPCON_INDX_GATING(2)
 #define INTEL_QEPCON_INDX_PAH_PBH	INTEL_QEPCON_INDX_GATING(3)
 #define INTEL_QEPCON_CAP_MODE		BIT(11)
 #define INTEL_QEPCON_FIFO_THRE_MASK	GENMASK(14, 12)
 #define INTEL_QEPCON_FIFO_THRE(n)	((((n) - 1) & 7) << 12)
 #define INTEL_QEPCON_FIFO_EMPTY		BIT(15)

 /* QEPFLT */
 #define INTEL_QEPFLT_MAX_COUNT(n)	((n) & 0x1fffff)

 /* QEPINT */
 #define INTEL_QEPINT_FIFOCRIT		BIT(5)
 #define INTEL_QEPINT_FIFOENTRY		BIT(4)
 #define INTEL_QEPINT_QEPDIR		BIT(3)
 #define INTEL_QEPINT_QEPRST_UP		BIT(2)
 #define INTEL_QEPINT_QEPRST_DOWN	BIT(1)
 #define INTEL_QEPINT_WDT		BIT(0)

 #define INTEL_QEPINT_MASK_ALL		GENMASK(5, 0)

 #define INTEL_QEP_CLK_PERIOD_NS		10

 struct intel_qep {
 	struct mutex lock;
 	struct device *dev;
 	void __iomem *regs;
 	bool enabled;
 	/* Context save registers */
 	u32 qepcon;
 	u32 qepflt;
 	u32 qepmax;
 };

 static inline u32 intel_qep_readl(struct intel_qep *qep, u32 offset)
 {
 	return readl(qep->regs + offset);
 }

 static inline void intel_qep_writel(struct intel_qep *qep,
 				    u32 offset, u32 value)
 {
 	writel(value, qep->regs + offset);
 }

 static void intel_qep_init(struct intel_qep *qep)
 {
 	u32 reg;

 	reg = intel_qep_readl(qep, INTEL_QEPCON);
 	reg &= ~INTEL_QEPCON_EN;
 	intel_qep_writel(qep, INTEL_QEPCON, reg);
 	qep->enabled = false;
 	/*
 	 * Make sure peripheral is disabled by flushing the write with
 	 * a dummy read
 	 */
 	reg = intel_qep_readl(qep, INTEL_QEPCON);

 	reg &= ~(INTEL_QEPCON_OP_MODE | INTEL_QEPCON_FLT_EN);
 	reg |= INTEL_QEPCON_EDGE_A | INTEL_QEPCON_EDGE_B |
 	       INTEL_QEPCON_EDGE_INDX | INTEL_QEPCON_COUNT_RST_MODE;
 	intel_qep_writel(qep, INTEL_QEPCON, reg);
 	intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL);
 }

 static int intel_qep_count_read(struct counter_device *counter,
 				struct counter_count *count, u64 *val)
 {
 	struct intel_qep *const qep = counter_priv(counter);

 	pm_runtime_get_sync(qep->dev);
 	*val = intel_qep_readl(qep, INTEL_QEPCOUNT);
 	pm_runtime_put(qep->dev);

 	return 0;
 }

 static const enum counter_function intel_qep_count_functions[] = {
 	COUNTER_FUNCTION_QUADRATURE_X4,
 };

 static int intel_qep_function_read(struct counter_device *counter,
 				   struct counter_count *count,
 				   enum counter_function *function)
 {
 	*function = COUNTER_FUNCTION_QUADRATURE_X4;

 	return 0;
 }

 static const enum counter_synapse_action intel_qep_synapse_actions[] = {
 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
 };

 static int intel_qep_action_read(struct counter_device *counter,
 				 struct counter_count *count,
 				 struct counter_synapse *synapse,
 				 enum counter_synapse_action *action)
 {
 	*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 	return 0;
 }

 static const struct counter_ops intel_qep_counter_ops = {
 	.count_read = intel_qep_count_read,
 	.function_read = intel_qep_function_read,
 	.action_read = intel_qep_action_read,
 };

 #define INTEL_QEP_SIGNAL(_id, _name) {				\
 	.id = (_id),						\
 	.name = (_name),					\
 }

 static struct counter_signal intel_qep_signals[] = {
 	INTEL_QEP_SIGNAL(0, "Phase A"),
 	INTEL_QEP_SIGNAL(1, "Phase B"),
 	INTEL_QEP_SIGNAL(2, "Index"),
 };

 #define INTEL_QEP_SYNAPSE(_signal_id) {				\
 	.actions_list = intel_qep_synapse_actions,		\
 	.num_actions = ARRAY_SIZE(intel_qep_synapse_actions),	\
 	.signal = &intel_qep_signals[(_signal_id)],		\
 }

 static struct counter_synapse intel_qep_count_synapses[] = {
 	INTEL_QEP_SYNAPSE(0),
 	INTEL_QEP_SYNAPSE(1),
 	INTEL_QEP_SYNAPSE(2),
 };

 static int intel_qep_ceiling_read(struct counter_device *counter,
 				  struct counter_count *count, u64 *ceiling)
 {
 	struct intel_qep *qep = counter_priv(counter);

 	pm_runtime_get_sync(qep->dev);
 	*ceiling = intel_qep_readl(qep, INTEL_QEPMAX);
 	pm_runtime_put(qep->dev);

 	return 0;
 }

 static int intel_qep_ceiling_write(struct counter_device *counter,
 				   struct counter_count *count, u64 max)
 {
 	struct intel_qep *qep = counter_priv(counter);
 	int ret = 0;

 	/* Intel QEP ceiling configuration only supports 32-bit values */
 	if (max != (u32)max)
 		return -ERANGE;

 	mutex_lock(&qep->lock);
 	if (qep->enabled) {
 		ret = -EBUSY;
 		goto out;
 	}

 	pm_runtime_get_sync(qep->dev);
 	intel_qep_writel(qep, INTEL_QEPMAX, max);
 	pm_runtime_put(qep->dev);

 out:
 	mutex_unlock(&qep->lock);
 	return ret;
 }

 static int intel_qep_enable_read(struct counter_device *counter,
 				 struct counter_count *count, u8 *enable)
 {
 	struct intel_qep *qep = counter_priv(counter);

 	*enable = qep->enabled;

 	return 0;
 }

 static int intel_qep_enable_write(struct counter_device *counter,
 				  struct counter_count *count, u8 val)
 {
 	struct intel_qep *qep = counter_priv(counter);
 	u32 reg;
 	bool changed;

 	mutex_lock(&qep->lock);
 	changed = val ^ qep->enabled;
 	if (!changed)
 		goto out;

 	pm_runtime_get_sync(qep->dev);
 	reg = intel_qep_readl(qep, INTEL_QEPCON);
 	if (val) {
 		/* Enable peripheral and keep runtime PM always on */
 		reg |= INTEL_QEPCON_EN;
 		pm_runtime_get_noresume(qep->dev);
 	} else {
 		/* Let runtime PM be idle and disable peripheral */
 		pm_runtime_put_noidle(qep->dev);
 		reg &= ~INTEL_QEPCON_EN;
 	}
 	intel_qep_writel(qep, INTEL_QEPCON, reg);
 	pm_runtime_put(qep->dev);
 	qep->enabled = val;

 out:
 	mutex_unlock(&qep->lock);
 	return 0;
 }

 static int intel_qep_spike_filter_ns_read(struct counter_device *counter,
 					  struct counter_count *count,
 					  u64 *length)
 {
 	struct intel_qep *qep = counter_priv(counter);
 	u32 reg;

 	pm_runtime_get_sync(qep->dev);
 	reg = intel_qep_readl(qep, INTEL_QEPCON);
 	if (!(reg & INTEL_QEPCON_FLT_EN)) {
 		pm_runtime_put(qep->dev);
 		return 0;
 	}
 	reg = INTEL_QEPFLT_MAX_COUNT(intel_qep_readl(qep, INTEL_QEPFLT));
 	pm_runtime_put(qep->dev);

 	*length = (reg + 2) * INTEL_QEP_CLK_PERIOD_NS;

 	return 0;
 }

 static int intel_qep_spike_filter_ns_write(struct counter_device *counter,
 					   struct counter_count *count,
 					   u64 length)
 {
 	struct intel_qep *qep = counter_priv(counter);
 	u32 reg;
 	bool enable;
 	int ret = 0;

 	/*
 	 * Spike filter length is (MAX_COUNT + 2) clock periods.
 	 * Disable filter when userspace writes 0, enable for valid
 	 * nanoseconds values and error out otherwise.
 	 */
 	do_div(length, INTEL_QEP_CLK_PERIOD_NS);
 	if (length == 0) {
 		enable = false;
 		length = 0;
 	} else if (length >= 2) {
 		enable = true;
 		length -= 2;
 	} else {
 		return -EINVAL;
 	}

 	if (length > INTEL_QEPFLT_MAX_COUNT(length))
 		return -ERANGE;

 	mutex_lock(&qep->lock);
 	if (qep->enabled) {
 		ret = -EBUSY;
 		goto out;
 	}

 	pm_runtime_get_sync(qep->dev);
 	reg = intel_qep_readl(qep, INTEL_QEPCON);
 	if (enable)
 		reg |= INTEL_QEPCON_FLT_EN;
 	else
 		reg &= ~INTEL_QEPCON_FLT_EN;
 	intel_qep_writel(qep, INTEL_QEPFLT, length);
 	intel_qep_writel(qep, INTEL_QEPCON, reg);
 	pm_runtime_put(qep->dev);

 out:
 	mutex_unlock(&qep->lock);
 	return ret;
 }

 static int intel_qep_preset_enable_read(struct counter_device *counter,
 					struct counter_count *count,
 					u8 *preset_enable)
 {
 	struct intel_qep *qep = counter_priv(counter);
 	u32 reg;

 	pm_runtime_get_sync(qep->dev);
 	reg = intel_qep_readl(qep, INTEL_QEPCON);
 	pm_runtime_put(qep->dev);

 	*preset_enable = !(reg & INTEL_QEPCON_COUNT_RST_MODE);

 	return 0;
 }

 static int intel_qep_preset_enable_write(struct counter_device *counter,
 					 struct counter_count *count, u8 val)
 {
 	struct intel_qep *qep = counter_priv(counter);
 	u32 reg;
 	int ret = 0;

 	mutex_lock(&qep->lock);
 	if (qep->enabled) {
 		ret = -EBUSY;
 		goto out;
 	}

 	pm_runtime_get_sync(qep->dev);
 	reg = intel_qep_readl(qep, INTEL_QEPCON);
 	if (val)
 		reg &= ~INTEL_QEPCON_COUNT_RST_MODE;
 	else
 		reg |= INTEL_QEPCON_COUNT_RST_MODE;

 	intel_qep_writel(qep, INTEL_QEPCON, reg);
 	pm_runtime_put(qep->dev);

 out:
 	mutex_unlock(&qep->lock);

 	return ret;
 }

 static struct counter_comp intel_qep_count_ext[] = {
 	COUNTER_COMP_ENABLE(intel_qep_enable_read, intel_qep_enable_write),
 	COUNTER_COMP_CEILING(intel_qep_ceiling_read, intel_qep_ceiling_write),
 	COUNTER_COMP_PRESET_ENABLE(intel_qep_preset_enable_read,
 				   intel_qep_preset_enable_write),
 	COUNTER_COMP_COUNT_U64("spike_filter_ns",
 			       intel_qep_spike_filter_ns_read,
 			       intel_qep_spike_filter_ns_write),
 };

 static struct counter_count intel_qep_counter_count[] = {
 	{
 		.id = 0,
 		.name = "Channel 1 Count",
 		.functions_list = intel_qep_count_functions,
 		.num_functions = ARRAY_SIZE(intel_qep_count_functions),
 		.synapses = intel_qep_count_synapses,
 		.num_synapses = ARRAY_SIZE(intel_qep_count_synapses),
 		.ext = intel_qep_count_ext,
 		.num_ext = ARRAY_SIZE(intel_qep_count_ext),
 	},
 };

 static int intel_qep_probe(struct pci_dev *pci, const struct pci_device_id *id)
 {
 	struct counter_device *counter;
 	struct intel_qep *qep;
 	struct device *dev = &pci->dev;
 	void __iomem *regs;
 	int ret;

 	counter = devm_counter_alloc(dev, sizeof(*qep));
 	if (!counter)
 		return -ENOMEM;
 	qep = counter_priv(counter);

 	ret = pcim_enable_device(pci);
 	if (ret)
 		return ret;

 	pci_set_master(pci);

 	ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
 	if (ret)
 		return ret;

 	regs = pcim_iomap_table(pci)[0];
 	if (!regs)
 		return -ENOMEM;

 	qep->dev = dev;
 	qep->regs = regs;
 	mutex_init(&qep->lock);

 	intel_qep_init(qep);
 	pci_set_drvdata(pci, qep);

 	counter->name = pci_name(pci);
 	counter->parent = dev;
 	counter->ops = &intel_qep_counter_ops;
 	counter->counts = intel_qep_counter_count;
 	counter->num_counts = ARRAY_SIZE(intel_qep_counter_count);
 	counter->signals = intel_qep_signals;
 	counter->num_signals = ARRAY_SIZE(intel_qep_signals);
 	qep->enabled = false;

 	pm_runtime_put(dev);
 	pm_runtime_allow(dev);

 	ret = devm_counter_add(&pci->dev, counter);
 	if (ret < 0)
 		return dev_err_probe(&pci->dev, ret, "Failed to add counter\n");

 	return 0;
 }

 static void intel_qep_remove(struct pci_dev *pci)
 {
 	struct intel_qep *qep = pci_get_drvdata(pci);
 	struct device *dev = &pci->dev;

 	pm_runtime_forbid(dev);
 	if (!qep->enabled)
 		pm_runtime_get(dev);

 	intel_qep_writel(qep, INTEL_QEPCON, 0);
 }

 static int __maybe_unused intel_qep_suspend(struct device *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct intel_qep *qep = pci_get_drvdata(pdev);

 	qep->qepcon = intel_qep_readl(qep, INTEL_QEPCON);
 	qep->qepflt = intel_qep_readl(qep, INTEL_QEPFLT);
 	qep->qepmax = intel_qep_readl(qep, INTEL_QEPMAX);

 	return 0;
 }

 static int __maybe_unused intel_qep_resume(struct device *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct intel_qep *qep = pci_get_drvdata(pdev);

 	/*
 	 * Make sure peripheral is disabled when restoring registers and
 	 * control register bits that are writable only when the peripheral
 	 * is disabled
 	 */
 	intel_qep_writel(qep, INTEL_QEPCON, 0);
 	intel_qep_readl(qep, INTEL_QEPCON);

 	intel_qep_writel(qep, INTEL_QEPFLT, qep->qepflt);
 	intel_qep_writel(qep, INTEL_QEPMAX, qep->qepmax);
 	intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL);

 	/* Restore all other control register bits except enable status */
 	intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon & ~INTEL_QEPCON_EN);
 	intel_qep_readl(qep, INTEL_QEPCON);

 	/* Restore enable status */
 	intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon);

 	return 0;
 }

 static UNIVERSAL_DEV_PM_OPS(intel_qep_pm_ops,
 			    intel_qep_suspend, intel_qep_resume, NULL);

 static const struct pci_device_id intel_qep_id_table[] = {
 	/* EHL */
 	{ PCI_VDEVICE(INTEL, 0x4bc3), },
 	{ PCI_VDEVICE(INTEL, 0x4b81), },
 	{ PCI_VDEVICE(INTEL, 0x4b82), },
 	{ PCI_VDEVICE(INTEL, 0x4b83), },
 	{  } /* Terminating Entry */
 };
 MODULE_DEVICE_TABLE(pci, intel_qep_id_table);

 static struct pci_driver intel_qep_driver = {
 	.name = "intel-qep",
 	.id_table = intel_qep_id_table,
 	.probe = intel_qep_probe,
 	.remove = intel_qep_remove,
 	.driver = {
 		.pm = &intel_qep_pm_ops,
 	}
 };

 module_pci_driver(intel_qep_driver);

 MODULE_AUTHOR("Felipe Balbi (Intel)");
 MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
 MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Intel Quadrature Encoder Peripheral driver");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Intel Quadrature Encoder Peripheral driver
	*
	* Copyright (C) 2019-2021 Intel Corporation
	*
	* Author: Felipe Balbi (Intel)
	* Author: Jarkko Nikula <jarkko.nikula@linux.intel.com>
	* Author: Raymond Tan <raymond.tan@intel.com>
	*/
	#include <linux/counter.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/pci.h>
	#include <linux/pm_runtime.h>

	#define INTEL_QEPCON 0x00
	#define INTEL_QEPFLT 0x04
	#define INTEL_QEPCOUNT 0x08
	#define INTEL_QEPMAX 0x0c
	#define INTEL_QEPWDT 0x10
	#define INTEL_QEPCAPDIV 0x14
	#define INTEL_QEPCNTR 0x18
	#define INTEL_QEPCAPBUF 0x1c
	#define INTEL_QEPINT_STAT 0x20
	#define INTEL_QEPINT_MASK 0x24

	/* QEPCON */
	#define INTEL_QEPCON_EN BIT(0)
	#define INTEL_QEPCON_FLT_EN BIT(1)
	#define INTEL_QEPCON_EDGE_A BIT(2)
	#define INTEL_QEPCON_EDGE_B BIT(3)
	#define INTEL_QEPCON_EDGE_INDX BIT(4)
	#define INTEL_QEPCON_SWPAB BIT(5)
	#define INTEL_QEPCON_OP_MODE BIT(6)
	#define INTEL_QEPCON_PH_ERR BIT(7)
	#define INTEL_QEPCON_COUNT_RST_MODE BIT(8)
	#define INTEL_QEPCON_INDX_GATING_MASK GENMASK(10, 9)
	#define INTEL_QEPCON_INDX_GATING(n) (((n) & 3) << 9)
	#define INTEL_QEPCON_INDX_PAL_PBL INTEL_QEPCON_INDX_GATING(0)
	#define INTEL_QEPCON_INDX_PAL_PBH INTEL_QEPCON_INDX_GATING(1)
	#define INTEL_QEPCON_INDX_PAH_PBL INTEL_QEPCON_INDX_GATING(2)
	#define INTEL_QEPCON_INDX_PAH_PBH INTEL_QEPCON_INDX_GATING(3)
	#define INTEL_QEPCON_CAP_MODE BIT(11)
	#define INTEL_QEPCON_FIFO_THRE_MASK GENMASK(14, 12)
	#define INTEL_QEPCON_FIFO_THRE(n) ((((n) - 1) & 7) << 12)
	#define INTEL_QEPCON_FIFO_EMPTY BIT(15)

	/* QEPFLT */
	#define INTEL_QEPFLT_MAX_COUNT(n) ((n) & 0x1fffff)

	/* QEPINT */
	#define INTEL_QEPINT_FIFOCRIT BIT(5)
	#define INTEL_QEPINT_FIFOENTRY BIT(4)
	#define INTEL_QEPINT_QEPDIR BIT(3)
	#define INTEL_QEPINT_QEPRST_UP BIT(2)
	#define INTEL_QEPINT_QEPRST_DOWN BIT(1)
	#define INTEL_QEPINT_WDT BIT(0)

	#define INTEL_QEPINT_MASK_ALL GENMASK(5, 0)

	#define INTEL_QEP_CLK_PERIOD_NS 10

	struct intel_qep {
	struct mutex lock;
	struct device *dev;
	void __iomem *regs;
	bool enabled;
	/* Context save registers */
	u32 qepcon;
	u32 qepflt;
	u32 qepmax;
	};

	static inline u32 intel_qep_readl(struct intel_qep *qep, u32 offset)
	{
	return readl(qep->regs + offset);
	}

	static inline void intel_qep_writel(struct intel_qep *qep,
	u32 offset, u32 value)
	{
	writel(value, qep->regs + offset);
	}

	static void intel_qep_init(struct intel_qep *qep)
	{
	u32 reg;

	reg = intel_qep_readl(qep, INTEL_QEPCON);
	reg &= ~INTEL_QEPCON_EN;
	intel_qep_writel(qep, INTEL_QEPCON, reg);
	qep->enabled = false;
	/*
	* Make sure peripheral is disabled by flushing the write with
	* a dummy read
	*/
	reg = intel_qep_readl(qep, INTEL_QEPCON);

	reg &= ~(INTEL_QEPCON_OP_MODE \| INTEL_QEPCON_FLT_EN);
	reg \|= INTEL_QEPCON_EDGE_A \| INTEL_QEPCON_EDGE_B \|
	INTEL_QEPCON_EDGE_INDX \| INTEL_QEPCON_COUNT_RST_MODE;
	intel_qep_writel(qep, INTEL_QEPCON, reg);
	intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL);
	}

	static int intel_qep_count_read(struct counter_device *counter,
	struct counter_count count, u64 val)
	{
	struct intel_qep *const qep = counter_priv(counter);

	pm_runtime_get_sync(qep->dev);
	*val = intel_qep_readl(qep, INTEL_QEPCOUNT);
	pm_runtime_put(qep->dev);

	return 0;
	}

	static const enum counter_function intel_qep_count_functions[] = {
	COUNTER_FUNCTION_QUADRATURE_X4,
	};

	static int intel_qep_function_read(struct counter_device *counter,
	struct counter_count *count,
	enum counter_function *function)
	{
	*function = COUNTER_FUNCTION_QUADRATURE_X4;

	return 0;
	}

	static const enum counter_synapse_action intel_qep_synapse_actions[] = {
	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
	};

	static int intel_qep_action_read(struct counter_device *counter,
	struct counter_count *count,
	struct counter_synapse *synapse,
	enum counter_synapse_action *action)
	{
	*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
	return 0;
	}

	static const struct counter_ops intel_qep_counter_ops = {
	.count_read = intel_qep_count_read,
	.function_read = intel_qep_function_read,
	.action_read = intel_qep_action_read,
	};

	#define INTEL_QEP_SIGNAL(_id, _name) { \
	.id = (_id), \
	.name = (_name), \
	}

	static struct counter_signal intel_qep_signals[] = {
	INTEL_QEP_SIGNAL(0, "Phase A"),
	INTEL_QEP_SIGNAL(1, "Phase B"),
	INTEL_QEP_SIGNAL(2, "Index"),
	};

	#define INTEL_QEP_SYNAPSE(_signal_id) { \
	.actions_list = intel_qep_synapse_actions, \
	.num_actions = ARRAY_SIZE(intel_qep_synapse_actions), \
	.signal = &intel_qep_signals[(_signal_id)], \
	}

	static struct counter_synapse intel_qep_count_synapses[] = {
	INTEL_QEP_SYNAPSE(0),
	INTEL_QEP_SYNAPSE(1),
	INTEL_QEP_SYNAPSE(2),
	};

	static int intel_qep_ceiling_read(struct counter_device *counter,
	struct counter_count count, u64 ceiling)
	{
	struct intel_qep *qep = counter_priv(counter);

	pm_runtime_get_sync(qep->dev);
	*ceiling = intel_qep_readl(qep, INTEL_QEPMAX);
	pm_runtime_put(qep->dev);

	return 0;
	}

	static int intel_qep_ceiling_write(struct counter_device *counter,
	struct counter_count *count, u64 max)
	{
	struct intel_qep *qep = counter_priv(counter);
	int ret = 0;

	/* Intel QEP ceiling configuration only supports 32-bit values */
	if (max != (u32)max)
	return -ERANGE;

	mutex_lock(&qep->lock);
	if (qep->enabled) {
	ret = -EBUSY;
	goto out;
	}

	pm_runtime_get_sync(qep->dev);
	intel_qep_writel(qep, INTEL_QEPMAX, max);
	pm_runtime_put(qep->dev);

	out:
	mutex_unlock(&qep->lock);
	return ret;
	}

	static int intel_qep_enable_read(struct counter_device *counter,
	struct counter_count count, u8 enable)
	{
	struct intel_qep *qep = counter_priv(counter);

	*enable = qep->enabled;

	return 0;
	}

	static int intel_qep_enable_write(struct counter_device *counter,
	struct counter_count *count, u8 val)
	{
	struct intel_qep *qep = counter_priv(counter);
	u32 reg;
	bool changed;

	mutex_lock(&qep->lock);
	changed = val ^ qep->enabled;
	if (!changed)
	goto out;

	pm_runtime_get_sync(qep->dev);
	reg = intel_qep_readl(qep, INTEL_QEPCON);
	if (val) {
	/* Enable peripheral and keep runtime PM always on */
	reg \|= INTEL_QEPCON_EN;
	pm_runtime_get_noresume(qep->dev);
	} else {
	/* Let runtime PM be idle and disable peripheral */
	pm_runtime_put_noidle(qep->dev);
	reg &= ~INTEL_QEPCON_EN;
	}
	intel_qep_writel(qep, INTEL_QEPCON, reg);
	pm_runtime_put(qep->dev);
	qep->enabled = val;

	out:
	mutex_unlock(&qep->lock);
	return 0;
	}

	static int intel_qep_spike_filter_ns_read(struct counter_device *counter,
	struct counter_count *count,
	u64 *length)
	{
	struct intel_qep *qep = counter_priv(counter);
	u32 reg;

	pm_runtime_get_sync(qep->dev);
	reg = intel_qep_readl(qep, INTEL_QEPCON);
	if (!(reg & INTEL_QEPCON_FLT_EN)) {
	pm_runtime_put(qep->dev);
	return 0;
	}
	reg = INTEL_QEPFLT_MAX_COUNT(intel_qep_readl(qep, INTEL_QEPFLT));
	pm_runtime_put(qep->dev);

	length = (reg + 2) INTEL_QEP_CLK_PERIOD_NS;

	return 0;
	}

	static int intel_qep_spike_filter_ns_write(struct counter_device *counter,
	struct counter_count *count,
	u64 length)
	{
	struct intel_qep *qep = counter_priv(counter);
	u32 reg;
	bool enable;
	int ret = 0;

	/*
	* Spike filter length is (MAX_COUNT + 2) clock periods.
	* Disable filter when userspace writes 0, enable for valid
	* nanoseconds values and error out otherwise.
	*/
	do_div(length, INTEL_QEP_CLK_PERIOD_NS);
	if (length == 0) {
	enable = false;
	length = 0;
	} else if (length >= 2) {
	enable = true;
	length -= 2;
	} else {
	return -EINVAL;
	}

	if (length > INTEL_QEPFLT_MAX_COUNT(length))
	return -ERANGE;

	mutex_lock(&qep->lock);
	if (qep->enabled) {
	ret = -EBUSY;
	goto out;
	}

	pm_runtime_get_sync(qep->dev);
	reg = intel_qep_readl(qep, INTEL_QEPCON);
	if (enable)
	reg \|= INTEL_QEPCON_FLT_EN;
	else
	reg &= ~INTEL_QEPCON_FLT_EN;
	intel_qep_writel(qep, INTEL_QEPFLT, length);
	intel_qep_writel(qep, INTEL_QEPCON, reg);
	pm_runtime_put(qep->dev);

	out:
	mutex_unlock(&qep->lock);
	return ret;
	}

	static int intel_qep_preset_enable_read(struct counter_device *counter,
	struct counter_count *count,
	u8 *preset_enable)
	{
	struct intel_qep *qep = counter_priv(counter);
	u32 reg;

	pm_runtime_get_sync(qep->dev);
	reg = intel_qep_readl(qep, INTEL_QEPCON);
	pm_runtime_put(qep->dev);

	*preset_enable = !(reg & INTEL_QEPCON_COUNT_RST_MODE);

	return 0;
	}

	static int intel_qep_preset_enable_write(struct counter_device *counter,
	struct counter_count *count, u8 val)
	{
	struct intel_qep *qep = counter_priv(counter);
	u32 reg;
	int ret = 0;

	mutex_lock(&qep->lock);
	if (qep->enabled) {
	ret = -EBUSY;
	goto out;
	}

	pm_runtime_get_sync(qep->dev);
	reg = intel_qep_readl(qep, INTEL_QEPCON);
	if (val)
	reg &= ~INTEL_QEPCON_COUNT_RST_MODE;
	else
	reg \|= INTEL_QEPCON_COUNT_RST_MODE;

	intel_qep_writel(qep, INTEL_QEPCON, reg);
	pm_runtime_put(qep->dev);

	out:
	mutex_unlock(&qep->lock);

	return ret;
	}

	static struct counter_comp intel_qep_count_ext[] = {
	COUNTER_COMP_ENABLE(intel_qep_enable_read, intel_qep_enable_write),
	COUNTER_COMP_CEILING(intel_qep_ceiling_read, intel_qep_ceiling_write),
	COUNTER_COMP_PRESET_ENABLE(intel_qep_preset_enable_read,
	intel_qep_preset_enable_write),
	COUNTER_COMP_COUNT_U64("spike_filter_ns",
	intel_qep_spike_filter_ns_read,
	intel_qep_spike_filter_ns_write),
	};

	static struct counter_count intel_qep_counter_count[] = {
	{
	.id = 0,
	.name = "Channel 1 Count",
	.functions_list = intel_qep_count_functions,
	.num_functions = ARRAY_SIZE(intel_qep_count_functions),
	.synapses = intel_qep_count_synapses,
	.num_synapses = ARRAY_SIZE(intel_qep_count_synapses),
	.ext = intel_qep_count_ext,
	.num_ext = ARRAY_SIZE(intel_qep_count_ext),
	},
	};

	static int intel_qep_probe(struct pci_dev pci, const struct pci_device_id id)
	{
	struct counter_device *counter;
	struct intel_qep *qep;
	struct device *dev = &pci->dev;
	void __iomem *regs;
	int ret;

	counter = devm_counter_alloc(dev, sizeof(*qep));
	if (!counter)
	return -ENOMEM;
	qep = counter_priv(counter);

	ret = pcim_enable_device(pci);
	if (ret)
	return ret;

	pci_set_master(pci);

	ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
	if (ret)
	return ret;

	regs = pcim_iomap_table(pci)[0];
	if (!regs)
	return -ENOMEM;

	qep->dev = dev;
	qep->regs = regs;
	mutex_init(&qep->lock);

	intel_qep_init(qep);
	pci_set_drvdata(pci, qep);

	counter->name = pci_name(pci);
	counter->parent = dev;
	counter->ops = &intel_qep_counter_ops;
	counter->counts = intel_qep_counter_count;
	counter->num_counts = ARRAY_SIZE(intel_qep_counter_count);
	counter->signals = intel_qep_signals;
	counter->num_signals = ARRAY_SIZE(intel_qep_signals);
	qep->enabled = false;

	pm_runtime_put(dev);
	pm_runtime_allow(dev);

	ret = devm_counter_add(&pci->dev, counter);
	if (ret < 0)
	return dev_err_probe(&pci->dev, ret, "Failed to add counter\n");

	return 0;
	}

	static void intel_qep_remove(struct pci_dev *pci)
	{
	struct intel_qep *qep = pci_get_drvdata(pci);
	struct device *dev = &pci->dev;

	pm_runtime_forbid(dev);
	if (!qep->enabled)
	pm_runtime_get(dev);

	intel_qep_writel(qep, INTEL_QEPCON, 0);
	}

	static int __maybe_unused intel_qep_suspend(struct device *dev)
	{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct intel_qep *qep = pci_get_drvdata(pdev);

	qep->qepcon = intel_qep_readl(qep, INTEL_QEPCON);
	qep->qepflt = intel_qep_readl(qep, INTEL_QEPFLT);
	qep->qepmax = intel_qep_readl(qep, INTEL_QEPMAX);

	return 0;
	}

	static int __maybe_unused intel_qep_resume(struct device *dev)
	{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct intel_qep *qep = pci_get_drvdata(pdev);

	/*
	* Make sure peripheral is disabled when restoring registers and
	* control register bits that are writable only when the peripheral
	* is disabled
	*/
	intel_qep_writel(qep, INTEL_QEPCON, 0);
	intel_qep_readl(qep, INTEL_QEPCON);

	intel_qep_writel(qep, INTEL_QEPFLT, qep->qepflt);
	intel_qep_writel(qep, INTEL_QEPMAX, qep->qepmax);
	intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL);

	/* Restore all other control register bits except enable status */
	intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon & ~INTEL_QEPCON_EN);
	intel_qep_readl(qep, INTEL_QEPCON);

	/* Restore enable status */
	intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon);

	return 0;
	}

	static UNIVERSAL_DEV_PM_OPS(intel_qep_pm_ops,
	intel_qep_suspend, intel_qep_resume, NULL);

	static const struct pci_device_id intel_qep_id_table[] = {
	/* EHL */
	{ PCI_VDEVICE(INTEL, 0x4bc3), },
	{ PCI_VDEVICE(INTEL, 0x4b81), },
	{ PCI_VDEVICE(INTEL, 0x4b82), },
	{ PCI_VDEVICE(INTEL, 0x4b83), },
	{ } /* Terminating Entry */
	};
	MODULE_DEVICE_TABLE(pci, intel_qep_id_table);

	static struct pci_driver intel_qep_driver = {
	.name = "intel-qep",
	.id_table = intel_qep_id_table,
	.probe = intel_qep_probe,
	.remove = intel_qep_remove,
	.driver = {
	.pm = &intel_qep_pm_ops,
	}
	};

	module_pci_driver(intel_qep_driver);

	MODULE_AUTHOR("Felipe Balbi (Intel)");
	MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
	MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Intel Quadrature Encoder Peripheral driver");