[3/3] counter: Add atmel TCB capture counter

diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index c80fa76bb531..c50d7453ec33 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -70,4 +70,15 @@  config FTM_QUADDEC
 	  To compile this driver as a module, choose M here: the
 	  module will be called ftm-quaddec.
 
+config ATMEL_TCB_CAPTURE
+	tristate "Atmel Timer Counter Capture driver"
+	depends on HAS_IOMEM && OF
+	select REGMAP_MMIO
+	help
+	  Select this option to enable the Atmel Timer Counter Block
+	  capture driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called atmel-tcb-capture.
+
 endif # COUNTER
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 55142d1f4c43..70c5b8924588 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -10,3 +10,4 @@  obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
 obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o
 obj-$(CONFIG_TI_EQEP)		+= ti-eqep.o
 obj-$(CONFIG_FTM_QUADDEC)	+= ftm-quaddec.o
+obj-$(CONFIG_ATMEL_TCB_CAPTURE)	+= atmel-tcb-capture.o
diff --git a/drivers/counter/atmel-tcb-capture.c b/drivers/counter/atmel-tcb-capture.c
new file mode 100644
index 000000000000..6ac809503f90
--- /dev/null
+++ b/drivers/counter/atmel-tcb-capture.c
@@ -0,0 +1,388 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/**
+ * Copyright (C) 2020 Atmel
+ *
+ * Author: Kamel Bouhara <kamel.bouhara@bootlin.com>
+ *
+ */
+#include <linux/clk.h>
+#include <linux/counter.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <soc/at91/atmel_tcb.h>
+
+#define ATMEL_TC_CMR_MASK	(ATMEL_TC_LDRA_RISING | ATMEL_TC_LDRB_FALLING | \
+				 ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \
+				 ATMEL_TC_LDBSTOP)
+
+#define ATMEL_TC_QDEN			BIT(8)
+#define ATMEL_TC_POSEN			BIT(9)
+
+struct atmel_tc_data {
+	const struct atmel_tcb_config *tc_cfg;
+	struct counter_device counter;
+	struct regmap *regmap;
+	int qdec_mode;
+	int num_channels;
+	int channel[2];
+	bool trig_inverted;
+};
+
+enum atmel_tc_count_function {
+	ATMEL_TC_FUNCTION_INCREASE,
+	ATMEL_TC_FUNCTION_QUADRATURE,
+};
+
+static enum counter_count_function atmel_tc_count_functions[] = {
+	[ATMEL_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
+	[ATMEL_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+};
+
+enum atmel_tc_synapse_action {
+	ATMEL_TC_SYNAPSE_ACTION_NONE = 0,
+	ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE,
+	ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE,
+	ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE
+};
+
+static enum counter_synapse_action atmel_tc_synapse_actions[] = {
+	[ATMEL_TC_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+	[ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	[ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	[ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+};
+
+static struct counter_signal atmel_tc_count_signals[] = {
+	{
+		.id = 0,
+		.name = "Channel A",
+	},
+	{
+		.id = 1,
+		.name = "Channel B",
+	}
+};
+
+static struct counter_synapse atmel_tc_count_synapses[] = {
+	{
+		.actions_list = atmel_tc_synapse_actions,
+		.num_actions = ARRAY_SIZE(atmel_tc_synapse_actions),
+		.signal = &atmel_tc_count_signals[0]
+	},
+	{
+		.actions_list = atmel_tc_synapse_actions,
+		.num_actions = ARRAY_SIZE(atmel_tc_synapse_actions),
+		.signal = &atmel_tc_count_signals[1]
+	}
+};
+
+static int atmel_tc_count_function_get(struct counter_device *counter,
+				       struct counter_count *count,
+				       size_t *function)
+{
+	struct atmel_tc_data *const priv = counter->priv;
+
+	if (priv->qdec_mode)
+		*function = ATMEL_TC_FUNCTION_QUADRATURE;
+	else
+		*function = ATMEL_TC_FUNCTION_INCREASE;
+
+	return 0;
+}
+
+static int atmel_tc_count_function_set(struct counter_device *counter,
+				       struct counter_count *count,
+				       size_t function)
+{
+	struct atmel_tc_data *const priv = counter->priv;
+	u32 bmr, cmr;
+
+	regmap_read(priv->regmap, ATMEL_TC_BMR, &bmr);
+	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
+
+	/* Set capture mode */
+	cmr &= ~ATMEL_TC_WAVE;
+
+	switch (function) {
+	case ATMEL_TC_FUNCTION_INCREASE:
+		priv->qdec_mode = 0;
+		/* Set highest rate based on whether soc has gclk or not */
+		bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN);
+		if (priv->tc_cfg->has_gclk)
+			cmr |= ATMEL_TC_TIMER_CLOCK2;
+		else
+			cmr |= ATMEL_TC_TIMER_CLOCK1;
+		/* Setup the period capture mode */
+		cmr |=  ATMEL_TC_CMR_MASK;
+		cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0);
+		break;
+	case ATMEL_TC_FUNCTION_QUADRATURE:
+		if (!priv->tc_cfg->has_qdec)
+			return -ENODEV;
+		/* In QDEC mode settings both channels 0 and 1 are required */
+		if (priv->num_channels < 2 || priv->channel[0] != 0 ||
+		    priv->channel[1] != 1) {
+			pr_err("Invalid channels number or id for quadrature mode\n");
+			return -EINVAL;
+		}
+		priv->qdec_mode = 1;
+		bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
+		cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
+		break;
+	}
+
+	regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
+	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), cmr);
+
+	/* Enable clock and trigger counter */
+	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CCR),
+		     ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
+
+	if (priv->qdec_mode) {
+		regmap_write(priv->regmap,
+			     ATMEL_TC_REG(priv->channel[1], CMR), cmr);
+		regmap_write(priv->regmap,
+			     ATMEL_TC_REG(priv->channel[1], CCR),
+			     ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
+	}
+
+	return 0;
+}
+
+static int atmel_tc_count_signal_read(struct counter_device *counter,
+				      struct counter_signal *signal,
+				      enum counter_signal_value *val)
+{
+	struct atmel_tc_data *const priv = counter->priv;
+	bool sigstatus;
+	u32 sr;
+
+	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr);
+
+	if (priv->trig_inverted)
+		sigstatus = (sr & ATMEL_TC_MTIOB);
+	else
+		sigstatus = (sr & ATMEL_TC_MTIOA);
+
+	*val = sigstatus ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+
+	return 0;
+}
+
+static int atmel_tc_count_action_get(struct counter_device *counter,
+				     struct counter_count *count,
+				     struct counter_synapse *synapse,
+				     size_t *action)
+{
+	struct atmel_tc_data *const priv = counter->priv;
+	u32 cmr;
+
+	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
+
+	*action = ATMEL_TC_SYNAPSE_ACTION_NONE;
+
+	if (cmr & ATMEL_TC_ETRGEDG_NONE)
+		*action = ATMEL_TC_SYNAPSE_ACTION_NONE;
+	else if (cmr & ATMEL_TC_ETRGEDG_RISING)
+		*action = ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE;
+	else if (cmr & ATMEL_TC_ETRGEDG_FALLING)
+		*action = ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE;
+	else if (cmr & ATMEL_TC_ETRGEDG_BOTH)
+		*action = ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE;
+
+	return 0;
+}
+
+static int atmel_tc_count_action_set(struct counter_device *counter,
+				     struct counter_count *count,
+				     struct counter_synapse *synapse,
+				     size_t action)
+{
+	struct atmel_tc_data *const priv = counter->priv;
+	u32 edge = ATMEL_TC_ETRGEDG_NONE;
+
+	switch (action) {
+	case ATMEL_TC_SYNAPSE_ACTION_NONE:
+		edge = ATMEL_TC_ETRGEDG_NONE;
+		break;
+	case ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE:
+		edge = ATMEL_TC_ETRGEDG_RISING;
+		break;
+	case ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE:
+		edge = ATMEL_TC_ETRGEDG_FALLING;
+		break;
+	case ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE:
+		edge = ATMEL_TC_ETRGEDG_BOTH;
+		break;
+	}
+
+	return regmap_write_bits(priv->regmap,
+				ATMEL_TC_REG(priv->channel[0], CMR),
+				ATMEL_TC_ETRGEDG, edge);
+}
+
+static int atmel_tc_count_read(struct counter_device *counter,
+			       struct counter_count *count,
+			       unsigned long *val)
+{
+	struct atmel_tc_data *const priv = counter->priv;
+	u32 cnt;
+
+	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CV), &cnt);
+	*val = cnt;
+
+	return 0;
+}
+
+static struct counter_count atmel_tc_count = {
+	.id = 0,
+	.name = "Timer Counter",
+	.functions_list = atmel_tc_count_functions,
+	.num_functions = ARRAY_SIZE(atmel_tc_count_functions),
+	.synapses = atmel_tc_count_synapses,
+	.num_synapses = ARRAY_SIZE(atmel_tc_count_synapses),
+};
+
+static struct counter_ops atmel_tc_ops = {
+	.signal_read  = atmel_tc_count_signal_read,
+	.count_read   = atmel_tc_count_read,
+	.count_write  = NULL,
+	.function_get = atmel_tc_count_function_get,
+	.function_set = atmel_tc_count_function_set,
+	.action_get   = atmel_tc_count_action_get,
+	.action_set   = atmel_tc_count_action_set
+};
+
+static const struct atmel_tcb_config tcb_rm9200_config = {
+		.counter_width = 16,
+};
+
+static const struct atmel_tcb_config tcb_sam9x5_config = {
+		.counter_width = 32,
+};
+
+static const struct atmel_tcb_config tcb_sama5d2_config = {
+		.counter_width = 32,
+		.has_gclk = true,
+		.has_qdec = true,
+};
+
+static const struct atmel_tcb_config tcb_sama5d3_config = {
+		.counter_width = 32,
+		.has_qdec = true,
+};
+
+static const struct of_device_id atmel_tc_of_match[] = {
+	{ .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
+	{ .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
+	{ .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
+	{ .compatible = "atmel,sama5d3-tcb", .data = &tcb_sama5d3_config, },
+	{ /* sentinel */ }
+};
+
+static int atmel_tc_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const struct atmel_tcb_config *tcb_config;
+	const struct of_device_id *match;
+	struct atmel_tc_data *priv;
+	char clk_name[] = "t0_clk";
+	struct regmap *regmap;
+	struct clk *clk[3];
+	int channel;
+	int ret, i;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	match = of_match_node(atmel_tc_of_match, np->parent);
+	tcb_config = match->data;
+	if (!tcb_config) {
+		dev_err(&pdev->dev, "No matching parent node found\n");
+		return -ENODEV;
+	}
+
+	regmap = syscon_node_to_regmap(np->parent);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	/* max. channels number is 2 when in QDEC mode */
+	priv->num_channels = of_property_count_u32_elems(np, "reg");
+	if (priv->num_channels < 0) {
+		dev_err(&pdev->dev, "Invalid or missing channel\n");
+		return -EINVAL;
+	}
+
+	/* Register channels and initialize clocks */
+	for (i = 0; i < priv->num_channels; i++) {
+		ret = of_property_read_u32_index(np, "reg", i, &channel);
+		if (ret < 0 || channel > 2)
+			return -ENODEV;
+
+		priv->channel[i] = channel;
+
+		clk_name[1] += channel;
+		clk[i] = of_clk_get_by_name(np->parent, clk_name);
+		if (IS_ERR(clk[i])) {
+			/* Fallback to t0_clk */
+			clk[i] = of_clk_get_by_name(np->parent, "t0_clk");
+			if (IS_ERR(clk[i]))
+				return PTR_ERR(clk[i]);
+		}
+
+		ret = clk_prepare_enable(clk[i]);
+		if (ret)
+			return ret;
+
+		dev_info(&pdev->dev,
+			 "Initialized capture mode on channel %d\n",
+			 channel);
+	}
+
+	priv->tc_cfg = tcb_config;
+	priv->regmap = regmap;
+	priv->counter.name = dev_name(&pdev->dev);
+	priv->counter.parent = &pdev->dev;
+	priv->counter.ops = &atmel_tc_ops;
+	priv->counter.num_counts = 1;
+	priv->counter.counts = &atmel_tc_count;
+	priv->counter.num_signals = ARRAY_SIZE(atmel_tc_count_signals);
+	priv->counter.signals = atmel_tc_count_signals;
+	priv->counter.priv = priv;
+
+	ret = devm_counter_register(&pdev->dev, &priv->counter);
+	if (ret < 0) {
+		for (i = 0; i < priv->num_channels; i++)
+			clk_disable_unprepare(clk[i]);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id atmel_tc_dt_ids[] = {
+	{ .compatible = "atmel,tcb-capture", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, atmel_tc_dt_ids);
+
+static struct platform_driver atmel_tc_driver = {
+	.probe = atmel_tc_probe,
+	.driver = {
+		.name = "atmel-tcb-capture",
+		.of_match_table = atmel_tc_dt_ids,
+	},
+};
+module_platform_driver(atmel_tc_driver);
+
+MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
+MODULE_DESCRIPTION("Atmel TCB Capture driver");
+MODULE_LICENSE("GPL v2");