kernel/drivers/counter/rz-mtu3-cnt.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Renesas RZ/G2L MTU3a Counter driver
 *
 * Copyright (C) 2022 Renesas Electronics Corporation
 */

#include <linux/clk.h>
#include <linux/counter.h>
#include <linux/mfd/rz-mtu3.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/types.h>

/*
 * Register descriptions
 *   TSR: Timer Status Register
 *   TMDR1: Timer Mode Register 1
 *   TMDR3: Timer Mode Register 3
 *   TIOR: Timer I/O Control Register
 *   TCR: Timer Control Register
 *   TCNT: Timer Counter
 *   TGRA: Timer general register A
 *   TCNTLW: Timer Longword Counter
 *   TGRALW: Timer longword general register A
 */

#define RZ_MTU3_TSR_TCFD	BIT(7) /* Count Direction Flag */

#define RZ_MTU3_TMDR1_PH_CNT_MODE_1	(4) /* Phase counting mode 1 */
#define RZ_MTU3_TMDR1_PH_CNT_MODE_2	(5) /* Phase counting mode 2 */
#define RZ_MTU3_TMDR1_PH_CNT_MODE_3	(6) /* Phase counting mode 3 */
#define RZ_MTU3_TMDR1_PH_CNT_MODE_4	(7) /* Phase counting mode 4 */
#define RZ_MTU3_TMDR1_PH_CNT_MODE_5	(9) /* Phase counting mode 5 */
#define RZ_MTU3_TMDR1_PH_CNT_MODE_MASK	(0xf)

/*
 * LWA: MTU1/MTU2 Combination Longword Access Control
 * 0: 16-bit, 1: 32-bit
 */
#define RZ_MTU3_TMDR3_LWA	(0)

/*
 * PHCKSEL: External Input Phase Clock Select
 * 0: MTCLKA and MTCLKB, 1: MTCLKC and MTCLKD
 */
#define RZ_MTU3_TMDR3_PHCKSEL	(1)

#define RZ_MTU3_16_BIT_MTU1_CH	(0)
#define RZ_MTU3_16_BIT_MTU2_CH	(1)
#define RZ_MTU3_32_BIT_CH	(2)

#define RZ_MTU3_TIOR_NO_OUTPUT	(0) /* Output prohibited */
#define RZ_MTU3_TIOR_IC_BOTH	(10) /* Input capture at both edges */

#define SIGNAL_A_ID	(0)
#define SIGNAL_B_ID	(1)
#define SIGNAL_C_ID	(2)
#define SIGNAL_D_ID	(3)

#define RZ_MTU3_MAX_HW_CNTR_CHANNELS	(2)
#define RZ_MTU3_MAX_LOGICAL_CNTR_CHANNELS	(3)

/**
 * struct rz_mtu3_cnt - MTU3 counter private data
 *
 * @clk: MTU3 module clock
 * @lock: Lock to prevent concurrent access for ceiling and count
 * @ch: HW channels for the counters
 * @count_is_enabled: Enabled state of Counter value channel
 * @mtu_16bit_max: Cache for 16-bit counters
 * @mtu_32bit_max: Cache for 32-bit counters
 */
struct rz_mtu3_cnt {
	struct clk *clk;
	struct mutex lock;
	struct rz_mtu3_channel *ch;
	bool count_is_enabled[RZ_MTU3_MAX_LOGICAL_CNTR_CHANNELS];
	union {
		u16 mtu_16bit_max[RZ_MTU3_MAX_HW_CNTR_CHANNELS];
		u32 mtu_32bit_max;
	};
};

static const enum counter_function rz_mtu3_count_functions[] = {
	COUNTER_FUNCTION_QUADRATURE_X4,
	COUNTER_FUNCTION_PULSE_DIRECTION,
	COUNTER_FUNCTION_QUADRATURE_X2_B,
};

static inline size_t rz_mtu3_get_hw_ch(const size_t id)
{
	return (id == RZ_MTU3_32_BIT_CH) ? 0 : id;
}

static inline struct rz_mtu3_channel *rz_mtu3_get_ch(struct counter_device *counter, int id)
{
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	const size_t ch_id = rz_mtu3_get_hw_ch(id);

	return &priv->ch[ch_id];
}

static bool rz_mtu3_is_counter_invalid(struct counter_device *counter, int id)
{
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	unsigned long tmdr;

	pm_runtime_get_sync(priv->ch->dev);
	tmdr = rz_mtu3_shared_reg_read(priv->ch, RZ_MTU3_TMDR3);
	pm_runtime_put(priv->ch->dev);

	if (id == RZ_MTU3_32_BIT_CH && test_bit(RZ_MTU3_TMDR3_LWA, &tmdr))
		return false;

	if (id != RZ_MTU3_32_BIT_CH && !test_bit(RZ_MTU3_TMDR3_LWA, &tmdr))
		return false;

	return true;
}

static int rz_mtu3_lock_if_counter_is_valid(struct counter_device *counter,
					    struct rz_mtu3_channel *const ch,
					    struct rz_mtu3_cnt *const priv,
					    int id)
{
	mutex_lock(&priv->lock);

	if (ch->is_busy && !priv->count_is_enabled[id]) {
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	if (rz_mtu3_is_counter_invalid(counter, id)) {
		mutex_unlock(&priv->lock);
		return -EBUSY;
	}

	return 0;
}

static int rz_mtu3_lock_if_count_is_enabled(struct rz_mtu3_channel *const ch,
					    struct rz_mtu3_cnt *const priv,
					    int id)
{
	mutex_lock(&priv->lock);

	if (ch->is_busy && !priv->count_is_enabled[id]) {
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	return 0;
}

static int rz_mtu3_count_read(struct counter_device *counter,
			      struct counter_count *count, u64 *val)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;

	ret = rz_mtu3_lock_if_counter_is_valid(counter, ch, priv, count->id);
	if (ret)
		return ret;

	pm_runtime_get_sync(ch->dev);
	if (count->id == RZ_MTU3_32_BIT_CH)
		*val = rz_mtu3_32bit_ch_read(ch, RZ_MTU3_TCNTLW);
	else
		*val = rz_mtu3_16bit_ch_read(ch, RZ_MTU3_TCNT);
	pm_runtime_put(ch->dev);
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_count_write(struct counter_device *counter,
			       struct counter_count *count, const u64 val)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;

	ret = rz_mtu3_lock_if_counter_is_valid(counter, ch, priv, count->id);
	if (ret)
		return ret;

	pm_runtime_get_sync(ch->dev);
	if (count->id == RZ_MTU3_32_BIT_CH)
		rz_mtu3_32bit_ch_write(ch, RZ_MTU3_TCNTLW, val);
	else
		rz_mtu3_16bit_ch_write(ch, RZ_MTU3_TCNT, val);
	pm_runtime_put(ch->dev);
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_count_function_read_helper(struct rz_mtu3_channel *const ch,
					      struct rz_mtu3_cnt *const priv,
					      enum counter_function *function)
{
	u8 timer_mode;

	pm_runtime_get_sync(ch->dev);
	timer_mode = rz_mtu3_8bit_ch_read(ch, RZ_MTU3_TMDR1);
	pm_runtime_put(ch->dev);

	switch (timer_mode & RZ_MTU3_TMDR1_PH_CNT_MODE_MASK) {
	case RZ_MTU3_TMDR1_PH_CNT_MODE_1:
		*function = COUNTER_FUNCTION_QUADRATURE_X4;
		return 0;
	case RZ_MTU3_TMDR1_PH_CNT_MODE_2:
		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
		return 0;
	case RZ_MTU3_TMDR1_PH_CNT_MODE_4:
		*function = COUNTER_FUNCTION_QUADRATURE_X2_B;
		return 0;
	default:
		/*
		 * TODO:
		 *  - need to add RZ_MTU3_TMDR1_PH_CNT_MODE_3
		 *  - need to add RZ_MTU3_TMDR1_PH_CNT_MODE_5
		 */
		return -EINVAL;
	}
}

static int rz_mtu3_count_function_read(struct counter_device *counter,
				       struct counter_count *count,
				       enum counter_function *function)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;

	ret = rz_mtu3_lock_if_count_is_enabled(ch, priv, count->id);
	if (ret)
		return ret;

	ret = rz_mtu3_count_function_read_helper(ch, priv, function);
	mutex_unlock(&priv->lock);

	return ret;
}

static int rz_mtu3_count_function_write(struct counter_device *counter,
					struct counter_count *count,
					enum counter_function function)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	u8 timer_mode;
	int ret;

	ret = rz_mtu3_lock_if_count_is_enabled(ch, priv, count->id);
	if (ret)
		return ret;

	switch (function) {
	case COUNTER_FUNCTION_QUADRATURE_X4:
		timer_mode = RZ_MTU3_TMDR1_PH_CNT_MODE_1;
		break;
	case COUNTER_FUNCTION_PULSE_DIRECTION:
		timer_mode = RZ_MTU3_TMDR1_PH_CNT_MODE_2;
		break;
	case COUNTER_FUNCTION_QUADRATURE_X2_B:
		timer_mode = RZ_MTU3_TMDR1_PH_CNT_MODE_4;
		break;
	default:
		/*
		 * TODO:
		 *  - need to add RZ_MTU3_TMDR1_PH_CNT_MODE_3
		 *  - need to add RZ_MTU3_TMDR1_PH_CNT_MODE_5
		 */
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	pm_runtime_get_sync(ch->dev);
	rz_mtu3_8bit_ch_write(ch, RZ_MTU3_TMDR1, timer_mode);
	pm_runtime_put(ch->dev);
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_count_direction_read(struct counter_device *counter,
					struct counter_count *count,
					enum counter_count_direction *direction)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;
	u8 tsr;

	ret = rz_mtu3_lock_if_count_is_enabled(ch, priv, count->id);
	if (ret)
		return ret;

	pm_runtime_get_sync(ch->dev);
	tsr = rz_mtu3_8bit_ch_read(ch, RZ_MTU3_TSR);
	pm_runtime_put(ch->dev);

	*direction = (tsr & RZ_MTU3_TSR_TCFD) ?
		COUNTER_COUNT_DIRECTION_FORWARD : COUNTER_COUNT_DIRECTION_BACKWARD;
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_count_ceiling_read(struct counter_device *counter,
				      struct counter_count *count,
				      u64 *ceiling)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	const size_t ch_id = rz_mtu3_get_hw_ch(count->id);
	int ret;

	ret = rz_mtu3_lock_if_counter_is_valid(counter, ch, priv, count->id);
	if (ret)
		return ret;

	switch (count->id) {
	case RZ_MTU3_16_BIT_MTU1_CH:
	case RZ_MTU3_16_BIT_MTU2_CH:
		*ceiling = priv->mtu_16bit_max[ch_id];
		break;
	case RZ_MTU3_32_BIT_CH:
		*ceiling = priv->mtu_32bit_max;
		break;
	default:
		/* should never reach this path */
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	mutex_unlock(&priv->lock);
	return 0;
}

static int rz_mtu3_count_ceiling_write(struct counter_device *counter,
				       struct counter_count *count,
				       u64 ceiling)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	const size_t ch_id = rz_mtu3_get_hw_ch(count->id);
	int ret;

	ret = rz_mtu3_lock_if_counter_is_valid(counter, ch, priv, count->id);
	if (ret)
		return ret;

	switch (count->id) {
	case RZ_MTU3_16_BIT_MTU1_CH:
	case RZ_MTU3_16_BIT_MTU2_CH:
		if (ceiling > U16_MAX) {
			mutex_unlock(&priv->lock);
			return -ERANGE;
		}
		priv->mtu_16bit_max[ch_id] = ceiling;
		break;
	case RZ_MTU3_32_BIT_CH:
		if (ceiling > U32_MAX) {
			mutex_unlock(&priv->lock);
			return -ERANGE;
		}
		priv->mtu_32bit_max = ceiling;
		break;
	default:
		/* should never reach this path */
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	pm_runtime_get_sync(ch->dev);
	if (count->id == RZ_MTU3_32_BIT_CH)
		rz_mtu3_32bit_ch_write(ch, RZ_MTU3_TGRALW, ceiling);
	else
		rz_mtu3_16bit_ch_write(ch, RZ_MTU3_TGRA, ceiling);

	rz_mtu3_8bit_ch_write(ch, RZ_MTU3_TCR, RZ_MTU3_TCR_CCLR_TGRA);
	pm_runtime_put(ch->dev);
	mutex_unlock(&priv->lock);

	return 0;
}

static void rz_mtu3_32bit_cnt_setting(struct counter_device *counter)
{
	struct rz_mtu3_channel *const ch1 = rz_mtu3_get_ch(counter, 0);
	struct rz_mtu3_channel *const ch2 = rz_mtu3_get_ch(counter, 1);

	/* Phase counting mode 1 is used as default in initialization. */
	rz_mtu3_8bit_ch_write(ch1, RZ_MTU3_TMDR1, RZ_MTU3_TMDR1_PH_CNT_MODE_1);

	rz_mtu3_8bit_ch_write(ch1, RZ_MTU3_TCR, RZ_MTU3_TCR_CCLR_TGRA);
	rz_mtu3_8bit_ch_write(ch1, RZ_MTU3_TIOR, RZ_MTU3_TIOR_IC_BOTH);

	rz_mtu3_enable(ch1);
	rz_mtu3_enable(ch2);
}

static void rz_mtu3_16bit_cnt_setting(struct counter_device *counter, int id)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, id);

	/* Phase counting mode 1 is used as default in initialization. */
	rz_mtu3_8bit_ch_write(ch, RZ_MTU3_TMDR1, RZ_MTU3_TMDR1_PH_CNT_MODE_1);

	rz_mtu3_8bit_ch_write(ch, RZ_MTU3_TCR, RZ_MTU3_TCR_CCLR_TGRA);
	rz_mtu3_8bit_ch_write(ch, RZ_MTU3_TIOR, RZ_MTU3_TIOR_NO_OUTPUT);
	rz_mtu3_enable(ch);
}

static int rz_mtu3_initialize_counter(struct counter_device *counter, int id)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, id);
	struct rz_mtu3_channel *const ch1 = rz_mtu3_get_ch(counter, 0);
	struct rz_mtu3_channel *const ch2 = rz_mtu3_get_ch(counter, 1);

	switch (id) {
	case RZ_MTU3_16_BIT_MTU1_CH:
	case RZ_MTU3_16_BIT_MTU2_CH:
		if (!rz_mtu3_request_channel(ch))
			return -EBUSY;

		rz_mtu3_16bit_cnt_setting(counter, id);
		return 0;
	case RZ_MTU3_32_BIT_CH:
		/*
		 * 32-bit phase counting need MTU1 and MTU2 to create 32-bit
		 * cascade counter.
		 */
		if (!rz_mtu3_request_channel(ch1))
			return -EBUSY;

		if (!rz_mtu3_request_channel(ch2)) {
			rz_mtu3_release_channel(ch1);
			return -EBUSY;
		}

		rz_mtu3_32bit_cnt_setting(counter);
		return 0;
	default:
		/* should never reach this path */
		return -EINVAL;
	}
}

static void rz_mtu3_terminate_counter(struct counter_device *counter, int id)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, id);
	struct rz_mtu3_channel *const ch1 = rz_mtu3_get_ch(counter, 0);
	struct rz_mtu3_channel *const ch2 = rz_mtu3_get_ch(counter, 1);

	if (id == RZ_MTU3_32_BIT_CH) {
		rz_mtu3_release_channel(ch2);
		rz_mtu3_release_channel(ch1);
		rz_mtu3_disable(ch2);
		rz_mtu3_disable(ch1);
	} else {
		rz_mtu3_release_channel(ch);
		rz_mtu3_disable(ch);
	}
}

static int rz_mtu3_count_enable_read(struct counter_device *counter,
				     struct counter_count *count, u8 *enable)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_channel *const ch1 = rz_mtu3_get_ch(counter, 0);
	struct rz_mtu3_channel *const ch2 = rz_mtu3_get_ch(counter, 1);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;

	ret = rz_mtu3_lock_if_count_is_enabled(ch, priv, count->id);
	if (ret)
		return ret;

	if (count->id == RZ_MTU3_32_BIT_CH)
		*enable = rz_mtu3_is_enabled(ch1) && rz_mtu3_is_enabled(ch2);
	else
		*enable = rz_mtu3_is_enabled(ch);

	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_count_enable_write(struct counter_device *counter,
				      struct counter_count *count, u8 enable)
{
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret = 0;

	if (enable) {
		mutex_lock(&priv->lock);
		pm_runtime_get_sync(ch->dev);
		ret = rz_mtu3_initialize_counter(counter, count->id);
		if (ret == 0)
			priv->count_is_enabled[count->id] = true;
		mutex_unlock(&priv->lock);
	} else {
		mutex_lock(&priv->lock);
		rz_mtu3_terminate_counter(counter, count->id);
		priv->count_is_enabled[count->id] = false;
		pm_runtime_put(ch->dev);
		mutex_unlock(&priv->lock);
	}

	return ret;
}

static int rz_mtu3_lock_if_ch0_is_enabled(struct rz_mtu3_cnt *const priv)
{
	mutex_lock(&priv->lock);
	if (priv->ch->is_busy && !(priv->count_is_enabled[RZ_MTU3_16_BIT_MTU1_CH] ||
				   priv->count_is_enabled[RZ_MTU3_32_BIT_CH])) {
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	return 0;
}

static int rz_mtu3_cascade_counts_enable_get(struct counter_device *counter,
					     u8 *cascade_enable)
{
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	unsigned long tmdr;
	int ret;

	ret = rz_mtu3_lock_if_ch0_is_enabled(priv);
	if (ret)
		return ret;

	pm_runtime_get_sync(priv->ch->dev);
	tmdr = rz_mtu3_shared_reg_read(priv->ch, RZ_MTU3_TMDR3);
	pm_runtime_put(priv->ch->dev);
	*cascade_enable = test_bit(RZ_MTU3_TMDR3_LWA, &tmdr);
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_cascade_counts_enable_set(struct counter_device *counter,
					     u8 cascade_enable)
{
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;

	ret = rz_mtu3_lock_if_ch0_is_enabled(priv);
	if (ret)
		return ret;

	pm_runtime_get_sync(priv->ch->dev);
	rz_mtu3_shared_reg_update_bit(priv->ch, RZ_MTU3_TMDR3,
				      RZ_MTU3_TMDR3_LWA, cascade_enable);
	pm_runtime_put(priv->ch->dev);
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_ext_input_phase_clock_select_get(struct counter_device *counter,
						    u32 *ext_input_phase_clock_select)
{
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	unsigned long tmdr;
	int ret;

	ret = rz_mtu3_lock_if_ch0_is_enabled(priv);
	if (ret)
		return ret;

	pm_runtime_get_sync(priv->ch->dev);
	tmdr = rz_mtu3_shared_reg_read(priv->ch, RZ_MTU3_TMDR3);
	pm_runtime_put(priv->ch->dev);
	*ext_input_phase_clock_select = test_bit(RZ_MTU3_TMDR3_PHCKSEL, &tmdr);
	mutex_unlock(&priv->lock);

	return 0;
}

static int rz_mtu3_ext_input_phase_clock_select_set(struct counter_device *counter,
						    u32 ext_input_phase_clock_select)
{
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	int ret;

	ret = rz_mtu3_lock_if_ch0_is_enabled(priv);
	if (ret)
		return ret;

	pm_runtime_get_sync(priv->ch->dev);
	rz_mtu3_shared_reg_update_bit(priv->ch, RZ_MTU3_TMDR3,
				      RZ_MTU3_TMDR3_PHCKSEL,
				      ext_input_phase_clock_select);
	pm_runtime_put(priv->ch->dev);
	mutex_unlock(&priv->lock);

	return 0;
}

static struct counter_comp rz_mtu3_count_ext[] = {
	COUNTER_COMP_DIRECTION(rz_mtu3_count_direction_read),
	COUNTER_COMP_ENABLE(rz_mtu3_count_enable_read,
			    rz_mtu3_count_enable_write),
	COUNTER_COMP_CEILING(rz_mtu3_count_ceiling_read,
			     rz_mtu3_count_ceiling_write),
};

static const enum counter_synapse_action rz_mtu3_synapse_actions[] = {
	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
	COUNTER_SYNAPSE_ACTION_NONE,
};

static int rz_mtu3_action_read(struct counter_device *counter,
			       struct counter_count *count,
			       struct counter_synapse *synapse,
			       enum counter_synapse_action *action)
{
	const bool is_signal_ab = (synapse->signal->id == SIGNAL_A_ID) ||
				  (synapse->signal->id == SIGNAL_B_ID);
	struct rz_mtu3_channel *const ch = rz_mtu3_get_ch(counter, count->id);
	struct rz_mtu3_cnt *const priv = counter_priv(counter);
	enum counter_function function;
	bool mtclkc_mtclkd;
	unsigned long tmdr;
	int ret;

	ret = rz_mtu3_lock_if_count_is_enabled(ch, priv, count->id);
	if (ret)
		return ret;

	ret = rz_mtu3_count_function_read_helper(ch, priv, &function);
	if (ret) {
		mutex_unlock(&priv->lock);
		return ret;
	}

	/* Default action mode */
	*action = COUNTER_SYNAPSE_ACTION_NONE;

	if (count->id != RZ_MTU3_16_BIT_MTU1_CH) {
		tmdr = rz_mtu3_shared_reg_read(priv->ch, RZ_MTU3_TMDR3);
		mtclkc_mtclkd = test_bit(RZ_MTU3_TMDR3_PHCKSEL, &tmdr);
		if ((mtclkc_mtclkd && is_signal_ab) ||
		    (!mtclkc_mtclkd && !is_signal_ab)) {
			mutex_unlock(&priv->lock);
			return 0;
		}
	}

	switch (function) {
	case COUNTER_FUNCTION_PULSE_DIRECTION:
		/*
		 * Rising edges on signal A (signal C) updates the respective
		 * count. The input level of signal B (signal D) determines
		 * direction.
		 */
		if (synapse->signal->id == SIGNAL_A_ID ||
		    synapse->signal->id == SIGNAL_C_ID)
			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
		break;
	case COUNTER_FUNCTION_QUADRATURE_X2_B:
		/*
		 * Any state transition on quadrature pair signal B (signal D)
		 * updates the respective count.
		 */
		if (synapse->signal->id == SIGNAL_B_ID ||
		    synapse->signal->id == SIGNAL_D_ID)
			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
		break;
	case COUNTER_FUNCTION_QUADRATURE_X4:
		/* counts up/down on both edges of A (C)  and B (D) signal */
		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
		break;
	default:
		/* should never reach this path */
		mutex_unlock(&priv->lock);
		return -EINVAL;
	}

	mutex_unlock(&priv->lock);

	return 0;
}

static const struct counter_ops rz_mtu3_cnt_ops = {
	.count_read = rz_mtu3_count_read,
	.count_write = rz_mtu3_count_write,
	.function_read = rz_mtu3_count_function_read,
	.function_write = rz_mtu3_count_function_write,
	.action_read = rz_mtu3_action_read,
};

#define RZ_MTU3_PHASE_SIGNAL(_id, _name) {		\
	.id = (_id),				\
	.name = (_name),			\
}

static struct counter_signal rz_mtu3_signals[] = {
	RZ_MTU3_PHASE_SIGNAL(SIGNAL_A_ID, "MTU1 MTCLKA"),
	RZ_MTU3_PHASE_SIGNAL(SIGNAL_B_ID, "MTU1 MTCLKB"),
	RZ_MTU3_PHASE_SIGNAL(SIGNAL_C_ID, "MTU2 MTCLKC"),
	RZ_MTU3_PHASE_SIGNAL(SIGNAL_D_ID, "MTU2 MTCLKD"),
};

static struct counter_synapse rz_mtu3_mtu1_count_synapses[] = {
	{
		.actions_list = rz_mtu3_synapse_actions,
		.num_actions = ARRAY_SIZE(rz_mtu3_synapse_actions),
		.signal = rz_mtu3_signals,
	},
	{
		.actions_list = rz_mtu3_synapse_actions,
		.num_actions = ARRAY_SIZE(rz_mtu3_synapse_actions),
		.signal = rz_mtu3_signals + 1,
	}
};

static struct counter_synapse rz_mtu3_mtu2_count_synapses[] = {
	{
		.actions_list = rz_mtu3_synapse_actions,
		.num_actions = ARRAY_SIZE(rz_mtu3_synapse_actions),
		.signal = rz_mtu3_signals,
	},
	{
		.actions_list = rz_mtu3_synapse_actions,
		.num_actions = ARRAY_SIZE(rz_mtu3_synapse_actions),
		.signal = rz_mtu3_signals + 1,
	},
	{
		.actions_list = rz_mtu3_synapse_actions,
		.num_actions = ARRAY_SIZE(rz_mtu3_synapse_actions),
		.signal = rz_mtu3_signals + 2,
	},
	{
		.actions_list = rz_mtu3_synapse_actions,
		.num_actions = ARRAY_SIZE(rz_mtu3_synapse_actions),
		.signal = rz_mtu3_signals + 3,
	}
};

static struct counter_count rz_mtu3_counts[] = {
	{
		.id = RZ_MTU3_16_BIT_MTU1_CH,
		.name = "Channel 1 Count",
		.functions_list = rz_mtu3_count_functions,
		.num_functions = ARRAY_SIZE(rz_mtu3_count_functions),
		.synapses = rz_mtu3_mtu1_count_synapses,
		.num_synapses = ARRAY_SIZE(rz_mtu3_mtu1_count_synapses),
		.ext = rz_mtu3_count_ext,
		.num_ext = ARRAY_SIZE(rz_mtu3_count_ext),
	},
	{
		.id = RZ_MTU3_16_BIT_MTU2_CH,
		.name = "Channel 2 Count",
		.functions_list = rz_mtu3_count_functions,
		.num_functions = ARRAY_SIZE(rz_mtu3_count_functions),
		.synapses = rz_mtu3_mtu2_count_synapses,
		.num_synapses = ARRAY_SIZE(rz_mtu3_mtu2_count_synapses),
		.ext = rz_mtu3_count_ext,
		.num_ext = ARRAY_SIZE(rz_mtu3_count_ext),
	},
	{
		.id = RZ_MTU3_32_BIT_CH,
		.name = "Channel 1 and 2 (cascaded) Count",
		.functions_list = rz_mtu3_count_functions,
		.num_functions = ARRAY_SIZE(rz_mtu3_count_functions),
		.synapses = rz_mtu3_mtu2_count_synapses,
		.num_synapses = ARRAY_SIZE(rz_mtu3_mtu2_count_synapses),
		.ext = rz_mtu3_count_ext,
		.num_ext = ARRAY_SIZE(rz_mtu3_count_ext),
	}
};

static const char *const rz_mtu3_ext_input_phase_clock_select[] = {
	"MTCLKA-MTCLKB",
	"MTCLKC-MTCLKD",
};

static DEFINE_COUNTER_ENUM(rz_mtu3_ext_input_phase_clock_select_enum,
			   rz_mtu3_ext_input_phase_clock_select);

static struct counter_comp rz_mtu3_device_ext[] = {
	COUNTER_COMP_DEVICE_BOOL("cascade_counts_enable",
				 rz_mtu3_cascade_counts_enable_get,
				 rz_mtu3_cascade_counts_enable_set),
	COUNTER_COMP_DEVICE_ENUM("external_input_phase_clock_select",
				 rz_mtu3_ext_input_phase_clock_select_get,
				 rz_mtu3_ext_input_phase_clock_select_set,
				 rz_mtu3_ext_input_phase_clock_select_enum),
};

static int rz_mtu3_cnt_pm_runtime_suspend(struct device *dev)
{
	struct clk *const clk = dev_get_drvdata(dev);

	clk_disable_unprepare(clk);

	return 0;
}

static int rz_mtu3_cnt_pm_runtime_resume(struct device *dev)
{
	struct clk *const clk = dev_get_drvdata(dev);

	clk_prepare_enable(clk);

	return 0;
}

static DEFINE_RUNTIME_DEV_PM_OPS(rz_mtu3_cnt_pm_ops,
				 rz_mtu3_cnt_pm_runtime_suspend,
				 rz_mtu3_cnt_pm_runtime_resume, NULL);

static void rz_mtu3_cnt_pm_disable(void *data)
{
	struct device *dev = data;

	pm_runtime_disable(dev);
	pm_runtime_set_suspended(dev);
}

static int rz_mtu3_cnt_probe(struct platform_device *pdev)
{
	struct rz_mtu3 *ddata = dev_get_drvdata(pdev->dev.parent);
	struct device *dev = &pdev->dev;
	struct counter_device *counter;
	struct rz_mtu3_channel *ch;
	struct rz_mtu3_cnt *priv;
	unsigned int i;
	int ret;

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

	priv = counter_priv(counter);
	priv->clk = ddata->clk;
	priv->mtu_32bit_max = U32_MAX;
	priv->ch = &ddata->channels[RZ_MTU3_CHAN_1];
	ch = &priv->ch[0];
	for (i = 0; i < RZ_MTU3_MAX_HW_CNTR_CHANNELS; i++) {
		ch->dev = dev;
		priv->mtu_16bit_max[i] = U16_MAX;
		ch++;
	}

	mutex_init(&priv->lock);
	platform_set_drvdata(pdev, priv->clk);
	clk_prepare_enable(priv->clk);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);
	ret = devm_add_action_or_reset(&pdev->dev, rz_mtu3_cnt_pm_disable, dev);
	if (ret < 0)
		goto disable_clock;

	counter->name = dev_name(dev);
	counter->parent = dev;
	counter->ops = &rz_mtu3_cnt_ops;
	counter->counts = rz_mtu3_counts;
	counter->num_counts = ARRAY_SIZE(rz_mtu3_counts);
	counter->signals = rz_mtu3_signals;
	counter->num_signals = ARRAY_SIZE(rz_mtu3_signals);
	counter->ext = rz_mtu3_device_ext;
	counter->num_ext = ARRAY_SIZE(rz_mtu3_device_ext);

	/* Register Counter device */
	ret = devm_counter_add(dev, counter);
	if (ret < 0) {
		dev_err_probe(dev, ret, "Failed to add counter\n");
		goto disable_clock;
	}

	return 0;

disable_clock:
	clk_disable_unprepare(priv->clk);

	return ret;
}

static struct platform_driver rz_mtu3_cnt_driver = {
	.probe = rz_mtu3_cnt_probe,
	.driver = {
		.name = "rz-mtu3-counter",
		.pm = pm_ptr(&rz_mtu3_cnt_pm_ops),
	},
};
module_platform_driver(rz_mtu3_cnt_driver);

MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
MODULE_ALIAS("platform:rz-mtu3-counter");
MODULE_DESCRIPTION("Renesas RZ/G2L MTU3a counter driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS(COUNTER);