Message-Id: <20220810140724.182389-4-jpanis@baylibre.com>
Date:   Wed, 10 Aug 2022 16:07:24 +0200
From:   Julien Panis <jpanis@...libre.com>
To:     vilhelm.gray@...il.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, mranostay@...com,
        Julien Panis <jpanis@...libre.com>
Subject: [PATCH v4 3/3] counter: capture-tiecap: capture driver support for ECAP

ECAP hardware on AM62x SoC supports capture feature. It can be used
to timestamp events (falling/rising edges) detected on signal input pin.

This commit adds capture driver support for ECAP hardware on AM62x SoC.

In the ECAP hardware, capture pin can also be configured to be in
PWM mode. Current implementation only supports capture operating mode.
Hardware also supports timebase sync between multiple instances, but
this driver supports simple independent capture functionality.

Signed-off-by: Julien Panis <jpanis@...libre.com>
---
 drivers/counter/Kconfig          |  14 +
 drivers/counter/Makefile         |   1 +
 drivers/counter/capture-tiecap.c | 634 +++++++++++++++++++++++++++++++
 include/uapi/linux/counter.h     |   2 +
 4 files changed, 651 insertions(+)
 create mode 100644 drivers/counter/capture-tiecap.c

diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 5edd155f1911..580640807a94 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -101,4 +101,18 @@ config INTEL_QEP
 	  To compile this driver as a module, choose M here: the module
 	  will be called intel-qep.
 
+config CAPTURE_TIECAP
+	tristate "TI eCAP capture driver"
+	depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX || ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  Select this option to enable the Texas Instruments Enhanced Capture
+	  (eCAP) driver in input mode.
+
+	  It can be used to timestamp events (falling/rising edges) detected
+	  on signal input pin.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called capture-tiecap.
+
 endif # COUNTER
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 8fde6c100ebc..7fac3e0985b5 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -14,3 +14,4 @@ obj-$(CONFIG_TI_EQEP)		+= ti-eqep.o
 obj-$(CONFIG_FTM_QUADDEC)	+= ftm-quaddec.o
 obj-$(CONFIG_MICROCHIP_TCB_CAPTURE)	+= microchip-tcb-capture.o
 obj-$(CONFIG_INTEL_QEP)		+= intel-qep.o
+obj-$(CONFIG_CAPTURE_TIECAP)	+= capture-tiecap.o
diff --git a/drivers/counter/capture-tiecap.c b/drivers/counter/capture-tiecap.c
new file mode 100644
index 000000000000..0601c65ef203
--- /dev/null
+++ b/drivers/counter/capture-tiecap.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ECAP Capture driver
+ *
+ * Copyright (C) 2022 Julien Panis <jpanis@...libre.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/counter.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+#define ECAP_DRV_NAME "ecap"
+
+/* Registers */
+#define ECAP_NB_CAP			4
+
+#define ECAP_TSCNT_REG			0x00
+
+#define ECAP_CAP_REG(i)		(((i) << 2) + 0x08)
+
+#define ECAP_ECCTL_REG			0x28
+#define ECAP_CAPPOL_BIT(i)		BIT((i) << 1)
+#define ECAP_EV_MODE_MASK		GENMASK(7, 0)
+#define ECAP_CAPLDEN_BIT		BIT(8)
+#define ECAP_CONT_ONESHT_BIT		BIT(16)
+#define ECAP_STOPVALUE_MASK		GENMASK(18, 17)
+#define ECAP_REARM_RESET_BIT		BIT(19)
+#define ECAP_TSCNTSTP_BIT		BIT(20)
+#define ECAP_SYNCO_DIS_MASK		GENMASK(23, 22)
+#define ECAP_CAP_APWM_BIT		BIT(25)
+#define ECAP_ECCTL_EN_MASK		(ECAP_CAPLDEN_BIT | ECAP_TSCNTSTP_BIT)
+#define ECAP_ECCTL_CFG_MASK		(ECAP_SYNCO_DIS_MASK | ECAP_STOPVALUE_MASK	\
+					| ECAP_ECCTL_EN_MASK | ECAP_REARM_RESET_BIT	\
+					| ECAP_CAP_APWM_BIT | ECAP_CONT_ONESHT_BIT)
+
+#define ECAP_ECINT_EN_FLG_REG		0x2c
+#define ECAP_NB_CEVT			(ECAP_NB_CAP + 1)
+#define ECAP_CEVT_EN_MASK		GENMASK(ECAP_NB_CEVT, ECAP_NB_CAP)
+#define ECAP_CEVT_FLG_BIT(i)		BIT((i) + 17)
+
+#define ECAP_ECINT_CLR_FRC_REG	0x30
+#define ECAP_INT_CLR_BIT		BIT(0)
+#define ECAP_CEVT_CLR_BIT(i)		BIT((i) + 1)
+#define ECAP_CEVT_CLR_MASK		GENMASK(ECAP_NB_CEVT, 0)
+
+#define ECAP_PID_REG			0x5c
+
+/*
+ * Event modes
+ * One bit for each CAPx register : 1 = falling edge / 0 = rising edge
+ * e.g. mode = 13 = 0xd = 0b1101
+ * -> falling edge for CAP1-3-4 / rising edge for CAP2
+ */
+#define ECAP_EV_MODE_BIT(i)		BIT(i)
+
+/* ECAP input */
+#define ECAP_SIGNAL 0
+
+static const struct regmap_config ecap_cnt_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = ECAP_PID_REG,
+};
+
+/**
+ * struct ecap_cnt_dev - device private data structure
+ * @enabled:      device state
+ * @clk:          device clock
+ * @clk_rate:     device clock rate
+ * @regmap:       device register map
+ * @elapsed_time: elapsed time since capture start
+ * @lock:         synchronization lock to prevent race conditions when computing times
+ * @pm_ctx:       device context for PM operations
+ */
+struct ecap_cnt_dev {
+	bool enabled;
+	struct clk *clk;
+	unsigned long clk_rate;
+	struct regmap *regmap;
+	__aligned_u64 elapsed_time;
+	spinlock_t lock;
+	struct {
+		u8 ev_mode;
+		unsigned int time_cntr;
+	} pm_ctx;
+};
+
+static u8 ecap_cnt_capture_get_evmode(struct counter_device *counter)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+	u8 ev_mode = 0;
+	unsigned int regval;
+	int i;
+
+	pm_runtime_get_sync(counter->parent);
+	regmap_read(ecap_dev->regmap, ECAP_ECCTL_REG, &regval);
+	pm_runtime_put_sync(counter->parent);
+
+	for (i = 0 ; i < ECAP_NB_CAP ; i++) {
+		if (regval & ECAP_CAPPOL_BIT(i))
+			ev_mode |= ECAP_EV_MODE_BIT(i);
+	}
+
+	return ev_mode;
+}
+
+static void ecap_cnt_capture_set_evmode(struct counter_device *counter, u8 ev_mode)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+	unsigned int regval = 0;
+	int i;
+
+	for (i = 0 ; i < ECAP_NB_CAP ; i++) {
+		if (ev_mode & ECAP_EV_MODE_BIT(i))
+			regval |= ECAP_CAPPOL_BIT(i);
+	}
+
+	pm_runtime_get_sync(counter->parent);
+	regmap_update_bits(ecap_dev->regmap, ECAP_ECCTL_REG, ECAP_EV_MODE_MASK, regval);
+	pm_runtime_put_sync(counter->parent);
+}
+
+static void ecap_cnt_capture_enable(struct counter_device *counter, bool rearm)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+	unsigned int regval;
+
+	pm_runtime_get_sync(counter->parent);
+
+	/* Enable interrupts on events */
+	regmap_update_bits(ecap_dev->regmap, ECAP_ECINT_EN_FLG_REG,
+			   ECAP_CEVT_EN_MASK, ECAP_CEVT_EN_MASK);
+
+	/* Run counter */
+	regval = ECAP_SYNCO_DIS_MASK | ECAP_STOPVALUE_MASK | ECAP_ECCTL_EN_MASK;
+	if (rearm) {
+		ecap_dev->elapsed_time = 0;
+		regmap_write(ecap_dev->regmap, ECAP_TSCNT_REG, 0);
+		regval |= ECAP_REARM_RESET_BIT;
+	}
+	regmap_update_bits(ecap_dev->regmap, ECAP_ECCTL_REG, ECAP_ECCTL_CFG_MASK, regval);
+}
+
+static void ecap_cnt_capture_disable(struct counter_device *counter)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+
+	/* Disable interrupts on events */
+	regmap_update_bits(ecap_dev->regmap, ECAP_ECINT_EN_FLG_REG, ECAP_CEVT_EN_MASK, 0);
+
+	/* Stop counter */
+	regmap_update_bits(ecap_dev->regmap, ECAP_ECCTL_REG, ECAP_ECCTL_EN_MASK, 0);
+
+	pm_runtime_put_sync(counter->parent);
+}
+
+static int ecap_cnt_count_get_ns(struct counter_device *counter, unsigned int reg, u64 *val)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+	unsigned int regval;
+	unsigned long flags;
+
+	pm_runtime_get_sync(counter->parent);
+	spin_lock_irqsave(&ecap_dev->lock, flags);
+
+	/* time_ns = 10^9 * (time_cycles + time_cumul) / clk_rate */
+	regmap_read(ecap_dev->regmap, reg, &regval);
+	*val = (regval + ecap_dev->elapsed_time) * NSEC_PER_SEC;
+	do_div(*val, ecap_dev->clk_rate);
+
+	spin_unlock_irqrestore(&ecap_dev->lock, flags);
+	pm_runtime_put_sync(counter->parent);
+
+	return 0;
+}
+
+static inline int ecap_cnt_count_read(struct counter_device *counter,
+				      struct counter_count *count,
+				      u64 *val)
+{
+	return ecap_cnt_count_get_ns(counter, ECAP_TSCNT_REG, val);
+}
+
+static int ecap_cnt_function_read(struct counter_device *counter,
+				  struct counter_count *count,
+				  enum counter_function *function)
+{
+	*function = COUNTER_FUNCTION_INCREASE;
+
+	return 0;
+}
+
+static int ecap_cnt_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 int ecap_cnt_watch_validate(struct counter_device *counter,
+				   const struct counter_watch *watch)
+{
+	struct counter_event_node *event_node;
+
+	if (watch->channel || watch->event != COUNTER_EVENT_CAPTURE)
+		return -EINVAL;
+
+	list_for_each_entry(event_node, &counter->next_events_list, l)
+		if (watch->component.type != COUNTER_COMPONENT_EXTENSION ||
+		    watch->component.scope != COUNTER_SCOPE_COUNT ||
+		    watch->component.parent ||
+		    watch->component.id >= ECAP_NB_CAP)
+			return -EINVAL;
+
+	return 0;
+}
+
+static int ecap_cnt_enable_read(struct counter_device *counter,
+				struct counter_count *count,
+				u8 *enable)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+
+	*enable = ecap_dev->enabled;
+
+	return 0;
+}
+
+static int ecap_cnt_enable_write(struct counter_device *counter,
+				 struct counter_count *count,
+				 u8 enable)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+
+	if (enable > 1)
+		return -EINVAL;
+	if (enable == ecap_dev->enabled)
+		return 0;
+	if (enable)
+		ecap_cnt_capture_enable(counter, true);
+	else
+		ecap_cnt_capture_disable(counter);
+	ecap_dev->enabled = enable;
+
+	return 0;
+}
+
+static int ecap_cnt_cap_get_pol(struct counter_device *counter,
+				struct counter_signal *signal,
+				u32 *pol, u8 inst)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+
+	pm_runtime_get_sync(counter->parent);
+	*pol = regmap_test_bits(ecap_dev->regmap, ECAP_ECCTL_REG, ECAP_CAPPOL_BIT(inst));
+	pm_runtime_put_sync(counter->parent);
+
+	return 0;
+}
+
+static int ecap_cnt_cap_set_pol(struct counter_device *counter,
+				struct counter_signal *signal,
+				u32 pol, u8 inst)
+{
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter);
+
+	if (ecap_dev->enabled)
+		return -EBUSY;
+	if (pol > 1)
+		return -EINVAL;
+
+	pm_runtime_get_sync(counter->parent);
+	if (pol)
+		regmap_set_bits(ecap_dev->regmap, ECAP_ECCTL_REG, ECAP_CAPPOL_BIT(inst));
+	else
+		regmap_clear_bits(ecap_dev->regmap, ECAP_ECCTL_REG, ECAP_CAPPOL_BIT(inst));
+	pm_runtime_put_sync(counter->parent);
+
+	return 0;
+}
+
+static inline int ecap_cnt_cap_read(struct counter_device *counter,
+				    struct counter_count *count,
+				    u64 *cap, u8 inst)
+{
+	return ecap_cnt_count_get_ns(counter, ECAP_CAP_REG(inst), cap);
+}
+
+static inline int ecap_cnt_cap1_get_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 *pol)
+{
+	return ecap_cnt_cap_get_pol(counter, signal, pol, 0);
+}
+
+static inline int ecap_cnt_cap2_get_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 *pol)
+{
+	return ecap_cnt_cap_get_pol(counter, signal, pol, 1);
+}
+
+static inline int ecap_cnt_cap3_get_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 *pol)
+{
+	return ecap_cnt_cap_get_pol(counter, signal, pol, 2);
+}
+
+static inline int ecap_cnt_cap4_get_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 *pol)
+{
+	return ecap_cnt_cap_get_pol(counter, signal, pol, 3);
+}
+
+static inline int ecap_cnt_cap1_set_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 pol)
+{
+	return ecap_cnt_cap_set_pol(counter, signal, pol, 0);
+}
+
+static inline int ecap_cnt_cap2_set_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 pol)
+{
+	return ecap_cnt_cap_set_pol(counter, signal, pol, 1);
+}
+
+static inline int ecap_cnt_cap3_set_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 pol)
+{
+	return ecap_cnt_cap_set_pol(counter, signal, pol, 2);
+}
+
+static inline int ecap_cnt_cap4_set_pol(struct counter_device *counter,
+					struct counter_signal *signal, u32 pol)
+{
+	return ecap_cnt_cap_set_pol(counter, signal, pol, 3);
+}
+
+static inline int ecap_cnt_cap1_read(struct counter_device *counter,
+				     struct counter_count *count, u64 *cap)
+{
+	return ecap_cnt_cap_read(counter, count, cap, 0);
+}
+
+static inline int ecap_cnt_cap2_read(struct counter_device *counter,
+				     struct counter_count *count, u64 *cap)
+{
+	return ecap_cnt_cap_read(counter, count, cap, 1);
+}
+
+static inline int ecap_cnt_cap3_read(struct counter_device *counter,
+				     struct counter_count *count, u64 *cap)
+{
+	return ecap_cnt_cap_read(counter, count, cap, 2);
+}
+
+static inline int ecap_cnt_cap4_read(struct counter_device *counter,
+				     struct counter_count *count, u64 *cap)
+{
+	return ecap_cnt_cap_read(counter, count, cap, 3);
+}
+
+static const struct counter_ops ecap_cnt_ops = {
+	.count_read = ecap_cnt_count_read,
+	.function_read = ecap_cnt_function_read,
+	.action_read = ecap_cnt_action_read,
+	.watch_validate = ecap_cnt_watch_validate,
+};
+
+static const enum counter_function ecap_cnt_functions[] = {
+	COUNTER_FUNCTION_INCREASE,
+};
+
+static const enum counter_synapse_action ecap_cnt_actions[] = {
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+};
+
+static const char *const ecap_cnt_cap_polarities[] = {
+	"rising",
+	"falling",
+};
+
+static DEFINE_COUNTER_ENUM(ecap_cnt_cap_avail_pol, ecap_cnt_cap_polarities);
+
+static struct counter_comp ecap_cnt_signal_ext[] = {
+	COUNTER_COMP_SIGNAL_ENUM("polarity1", ecap_cnt_cap1_get_pol,
+				 ecap_cnt_cap1_set_pol, ecap_cnt_cap_avail_pol),
+	COUNTER_COMP_SIGNAL_ENUM("polarity2", ecap_cnt_cap2_get_pol,
+				 ecap_cnt_cap2_set_pol, ecap_cnt_cap_avail_pol),
+	COUNTER_COMP_SIGNAL_ENUM("polarity3", ecap_cnt_cap3_get_pol,
+				 ecap_cnt_cap3_set_pol, ecap_cnt_cap_avail_pol),
+	COUNTER_COMP_SIGNAL_ENUM("polarity4", ecap_cnt_cap4_get_pol,
+				 ecap_cnt_cap4_set_pol, ecap_cnt_cap_avail_pol),
+};
+
+static struct counter_signal ecap_cnt_signals[] = {
+	{
+		.id = ECAP_SIGNAL,
+		.name = "ECAPSIG",
+		.ext = ecap_cnt_signal_ext,
+		.num_ext = ARRAY_SIZE(ecap_cnt_signal_ext),
+	},
+};
+
+static struct counter_synapse ecap_cnt_synapses[] = {
+	{
+		.actions_list = ecap_cnt_actions,
+		.num_actions = ARRAY_SIZE(ecap_cnt_actions),
+		.signal = &ecap_cnt_signals[ECAP_SIGNAL],
+	},
+};
+
+static struct counter_comp ecap_cnt_count_ext[] = {
+	COUNTER_COMP_COUNT_U64("capture1", ecap_cnt_cap1_read, NULL),
+	COUNTER_COMP_COUNT_U64("capture2", ecap_cnt_cap2_read, NULL),
+	COUNTER_COMP_COUNT_U64("capture3", ecap_cnt_cap3_read, NULL),
+	COUNTER_COMP_COUNT_U64("capture4", ecap_cnt_cap4_read, NULL),
+	COUNTER_COMP_ENABLE(ecap_cnt_enable_read, ecap_cnt_enable_write),
+};
+
+static struct counter_count ecap_cnt_counts[] = {
+	{
+		.id = 0,
+		.name = "ECAPCNT",
+		.functions_list = ecap_cnt_functions,
+		.num_functions = ARRAY_SIZE(ecap_cnt_functions),
+		.synapses = ecap_cnt_synapses,
+		.num_synapses = ARRAY_SIZE(ecap_cnt_synapses),
+		.ext = ecap_cnt_count_ext,
+		.num_ext = ARRAY_SIZE(ecap_cnt_count_ext),
+	},
+};
+
+static irqreturn_t ecap_cnt_isr(int irq, void *dev_id)
+{
+	struct counter_device *counter_dev = dev_id;
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter_dev);
+	unsigned int clr = 0;
+	unsigned int flg;
+	int i;
+	unsigned long flags;
+
+	regmap_read(ecap_dev->regmap, ECAP_ECINT_EN_FLG_REG, &flg);
+
+	for (i = ECAP_NB_CAP - 1 ; i < ECAP_NB_CEVT ; i++) {
+		if (flg & ECAP_CEVT_FLG_BIT(i)) {
+			if (i < ECAP_NB_CAP) {
+				/* Input signal edge detected on last CAP (CAP4) */
+				counter_push_event(counter_dev, COUNTER_EVENT_CAPTURE, 0);
+			} else {
+				/* Counter overflow */
+				spin_lock_irqsave(&ecap_dev->lock, flags);
+				ecap_dev->elapsed_time += (u64)U32_MAX + 1;
+				spin_unlock_irqrestore(&ecap_dev->lock, flags);
+			}
+
+			clr |= ECAP_CEVT_CLR_BIT(i);
+		}
+	}
+
+	clr |= ECAP_INT_CLR_BIT;
+	regmap_update_bits(ecap_dev->regmap, ECAP_ECINT_CLR_FRC_REG, ECAP_CEVT_CLR_MASK, clr);
+
+	return IRQ_HANDLED;
+}
+
+static void ecap_cnt_clk_disable(void *clk)
+{
+	clk_disable_unprepare(clk);
+}
+
+static int ecap_cnt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ecap_cnt_dev *ecap_dev;
+	struct counter_device *counter_dev;
+	void __iomem *mmio_base;
+	int ret;
+
+	counter_dev = devm_counter_alloc(dev, sizeof(*ecap_dev));
+	if (IS_ERR(counter_dev))
+		return PTR_ERR(counter_dev);
+
+	counter_dev->name = ECAP_DRV_NAME;
+	counter_dev->parent = dev;
+	counter_dev->ops = &ecap_cnt_ops;
+	counter_dev->signals = ecap_cnt_signals;
+	counter_dev->num_signals = ARRAY_SIZE(ecap_cnt_signals);
+	counter_dev->counts = ecap_cnt_counts;
+	counter_dev->num_counts = ARRAY_SIZE(ecap_cnt_counts);
+
+	ecap_dev = counter_priv(counter_dev);
+
+	ecap_dev->clk = devm_clk_get(dev, "fck");
+	if (IS_ERR(ecap_dev->clk))
+		return dev_err_probe(dev, PTR_ERR(ecap_dev->clk), "failed to get clock\n");
+
+	ret = clk_prepare_enable(ecap_dev->clk);
+	if (ret) {
+		dev_err(dev, "failed to enable clock\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev, ecap_cnt_clk_disable, ecap_dev->clk);
+	if (ret) {
+		dev_err(dev, "failed to add clock disable action\n");
+		return ret;
+	}
+
+	ecap_dev->clk_rate = clk_get_rate(ecap_dev->clk);
+	if (!ecap_dev->clk_rate) {
+		dev_err(dev, "failed to get clock rate\n");
+		return -EINVAL;
+	}
+
+	mmio_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mmio_base))
+		return PTR_ERR(mmio_base);
+
+	ecap_dev->regmap = devm_regmap_init_mmio(dev, mmio_base, &ecap_cnt_regmap_config);
+	if (IS_ERR(ecap_dev->regmap))
+		return dev_err_probe(dev, PTR_ERR(ecap_dev->regmap), "failed to init regmap\n");
+
+	spin_lock_init(&ecap_dev->lock);
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "failed to get irq\n");
+		return ret;
+	}
+
+	ret = devm_request_irq(dev, ret, ecap_cnt_isr, 0, pdev->name, counter_dev);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, counter_dev);
+	pm_runtime_enable(dev);
+
+	ecap_dev->enabled = 0;
+	ecap_cnt_capture_set_evmode(counter_dev, 0);
+
+	ret = devm_counter_add(dev, counter_dev);
+	if (ret) {
+		dev_err(dev, "failed to add counter\n");
+		pm_runtime_disable(dev);
+	}
+
+	return ret;
+}
+
+static int ecap_cnt_remove(struct platform_device *pdev)
+{
+	struct counter_device *counter_dev = platform_get_drvdata(pdev);
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter_dev);
+
+	if (ecap_dev->enabled)
+		ecap_cnt_capture_disable(counter_dev);
+
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static int ecap_cnt_suspend(struct device *dev)
+{
+	struct counter_device *counter_dev = dev_get_drvdata(dev);
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter_dev);
+
+	/* If eCAP is running, stop capture then save timestamp counter */
+	if (ecap_dev->enabled) {
+		ecap_cnt_capture_disable(counter_dev);
+
+		pm_runtime_get_sync(dev);
+		regmap_read(ecap_dev->regmap, ECAP_TSCNT_REG, &ecap_dev->pm_ctx.time_cntr);
+		pm_runtime_put_sync(dev);
+	}
+
+	ecap_dev->pm_ctx.ev_mode = ecap_cnt_capture_get_evmode(counter_dev);
+
+	return 0;
+}
+
+static int ecap_cnt_resume(struct device *dev)
+{
+	struct counter_device *counter_dev = dev_get_drvdata(dev);
+	struct ecap_cnt_dev *ecap_dev = counter_priv(counter_dev);
+
+	ecap_cnt_capture_set_evmode(counter_dev, ecap_dev->pm_ctx.ev_mode);
+
+	/* If eCAP was running, restore timestamp counter then run capture */
+	if (ecap_dev->enabled) {
+		pm_runtime_get_sync(dev);
+		regmap_write(ecap_dev->regmap, ECAP_TSCNT_REG, ecap_dev->pm_ctx.time_cntr);
+		pm_runtime_put_sync(dev);
+
+		ecap_cnt_capture_enable(counter_dev, false);
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ecap_cnt_pm_ops, ecap_cnt_suspend, ecap_cnt_resume);
+
+static const struct of_device_id ecap_cnt_of_match[] = {
+	{ .compatible	= "ti,am62-ecap-capture" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ecap_cnt_of_match);
+
+static struct platform_driver ecap_cnt_driver = {
+	.probe = ecap_cnt_probe,
+	.remove = ecap_cnt_remove,
+	.driver = {
+		.name = "ecap-capture",
+		.of_match_table = ecap_cnt_of_match,
+		.pm = pm_sleep_ptr(&ecap_cnt_pm_ops),
+	},
+};
+module_platform_driver(ecap_cnt_driver);
+
+MODULE_DESCRIPTION("ECAP Capture driver");
+MODULE_AUTHOR("Julien Panis <jpanis@...libre.com>");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
index 96c5ffd368ad..4c5372c6f2a3 100644
--- a/include/uapi/linux/counter.h
+++ b/include/uapi/linux/counter.h
@@ -63,6 +63,8 @@ enum counter_event_type {
 	COUNTER_EVENT_INDEX,
 	/* State of counter is changed */
 	COUNTER_EVENT_CHANGE_OF_STATE,
+	/* Count value is captured */
+	COUNTER_EVENT_CAPTURE,
 };
 
 /**
-- 
2.25.1

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