diff mbox series

[v9,4/5] counter: Add Renesas RZ/G2L MTU3a counter driver

Message ID 20221214103136.2493474-5-biju.das.jz@bp.renesas.com (mailing list archive)
State Handled Elsewhere
Headers show
Series None | expand

Commit Message

Biju Das Dec. 14, 2022, 10:31 a.m. UTC
Add RZ/G2L MTU3a counter driver. This IP supports the following
phase counting modes on MTU1 and MTU2 channels

1) 16-bit phase counting modes on MTU1 and MTU2 channels.
2) 32-bit phase counting mode by cascading MTU1 and MTU2 channels.

This patch adds 3 counter value channels.
	count0: 16-bit phase counter value channel on MTU1
	count1: 16-bit phase counter value channel on MTU2
	count2: 32-bit phase counter value channel by cascading
                MTU1 and MTU2 channels.

The external input phase clock pin for the counter value channels
are as follows:
	count0: "MTCLKA-MTCLKB"
	count1: "MTCLKA-MTCLKB" or "MTCLKC-MTCLKD"
	count2: "MTCLKA-MTCLKB" or "MTCLKC-MTCLKD"

Use the sysfs variable "external_input_phase_clock_select" to select the
external input phase clock pin and "cascade_counts_enable" to enable/
disable cascading of channels.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v8->v9:
 * Added count_is_enabled variable to struct rz_mtu3_cnt
 * Added check for ch->is_busy and count_is_enabled before every Counter
   callback to ensure we do not try to access a busy channel used by other
   subsystem(eg: pwm).
 * Removed id parameter from rz_mtu3_32bit_cnt_setting()
 * Made defintion of rz_mtu3_get_ch() in single line.
 * Replaced break->return in rz_mtu3_32bit_cnt_setting(),
   rz_mtu3_count_function_read() and rz_mtu3_initialize_counter()
   and removed redundant return 0.
 * Simplified synapse signal check for rz_mtu3_action_read().
v7->v8:
 * Simplified rz_mtu3_initialize_counter by calling rz_mtu3_request_
   channel() and release the acquired sibling channel in case of error.
 * Simplified rz_mtu3_terminate_counter by calling rz_mtu3_release_
   channel().
 * Removed unused ceiling and ch_id from rz_mtu3_count_write()
 * Replaced the error -EINVAL->-EBUSY for rz_mtu3_is_counter_invalid()
 * Avoided race between rz_mtu3_count_{read, write} with rz_mtu3_
   cascade_counts_enable_set() by adding locks and moved the lock
   before rz_mtu3_is_counter_invalid()
 * Protected the rz_mtu3_count_ceiling_read() function with a lock
   to make sure the cascade operation mode doesn't not change and
   that the priv data structure accesses don't race when they are
   changed in the ceiling_write() callback.
 * Added lock in rz_mtu3_cascade_enable_set() to make sure the other
   callbacks don't try to read the LWA state while updating LWA.
 * Added lock in rz_mtu3_ext_input_phase_clock_select_set() to ensure
   the other callbacks don't try to read the PHCKSEL state while updating
   PHCKSEL.
 * Added lock to avoid race between rz_mtu3_count_function_write() and
   rz_mtu3_action_read()
 * Updated rz_mtu3_action_read to return 0, if Synapse is in COUNTER_SYNAPSE
   _ACTION_NONE state.
 * Replaced sysfs variable cascade_enable->cascade_counts_enable
 * Renamed rz_mtu3_cascade_enable_get->rz_mtu3_cascade_counts_enable_get
 * Renamed rz_mtu3_cascade_enable_set->rz_mtu3_cascade_counts_enable_set
 * Removed redundent ceiling assignment from rz_mtu3_count_ceiling_read()
 * Removed unused ceiling and ch_id from rz_mtu3_count_write().
v6->v7:
 * Updated commit description
 * Added Register descriptions
 * Opimized size of cache variable by using union
 * Used test_bit() in rz_mtu3_is_counter_invalid()
 * Replaced val->timer_mode in rz_mtu3_count_function_{read,write}
 * Added TODO comment phase3 and phase5 modes.
 * replaced if-else with ternary expression in rz_mtu3_count_direction_read()
 * Used switch statement in rz_mtu3_count_ceiling_read to consistent with write
 * Provided default case for all switch statement.
 * Add mutex lock for avoiding races with other devices
 * Updated comments in rz_mtu3_action_read
 * Replaced COUNTER_COMP_DEVICE_BOOL->COUNTER_COMP_DEVICE_BOOL for 
   cascade_enable
 * Replaced RZ_MTU3_GET_HW_CH->rz_mtu3_get_hw_ch
 * Added rz_mtu3_get_ch() to get channels
 * used rz_mtu3_shared_reg_update_bit for cascade_enable and
   selecting phase input clock.
 * Added rz_mtu3_is_counter_invalid() check in rz_mtu3_count_ceiling_read()
v5->v6:
 * Updated KConfig and commit description
 * Sorted header
 * Fixed RZ_MTU3_GET_HW_CH Macro for argument reuse 'id' - 
   possible side-effects?
 * Replaced SET_RUNTIME_PM_OPS->DEFINE_RUNTIME_DEV_PM_OPS and removed
   __maybe_unused from suspend/resume()
v4->v5:
 * Updated the Kconfig with SoC vendor name
 * Introduced rz_mtu3_is_counter_invalid()
 * replaced pointer to an array of struct rz_mtu3_channel with
   a simple pointer to struct rz_mtu3_channel.
 * Added long_word_access_ctrl_mode sysfs entry for 16-bit and
   32-bit access
 * Added external_input_phase_clock_select sysfs entry for
   selecting input clocks.
 * used preprocessor defines represent SIGNAL_{A,B,C,D}_ID instead of
   signal ids.
v3->v4:
 * There is no resource associated with "rz-mtu3-counter" compatible
   and moved the code to mfd subsystem as it binds against "rz-mtu".
 * Removed struct platform_driver rz_mtu3_cnt_driver.
 * Updated commit description
 * Updated Kconfig description
 * Added macros RZ_MTU3_16_BIT_MTU{1,2}_CH for MTU1 and MTU2 channels
 * Added RZ_MTU3_GET_HW_CH macro for getting channel ID.
 * replaced priv->ch[id]->priv->ch[0] in rz_mtu3_count_read()
 * Cached counter max values
 * replaced cnt->tsr in rz_mtu3_count_direction_read()
 * Added comments for RZ_MTU3_TCR_CCLR_NONE
 * Replaced if with switch in rz_mtu3_initialize_counter() and
   rz_mtu3_count_ceiling_write()
 * Added locks in initialize, terminate and enable_read to prevent races.
 * Updated rz_mtu3_action_read to take care of MTU2 signals.
 * Added separate distinct array for each group of Synapse.
 * Moved pm handling to parent.

v1->v3:
 * Modelled as a counter device supporting 3 counters(2 16-bit and 
   32-bit)
 * Add kernel-doc comments to document struct rz_mtu3_cnt
 * Removed mmio variable from struct rz_mtu3_cnt
 * Removed cnt local variable from rz_mtu3_count_read()
 * Replaced -EINVAL->-ERANGE for out of range error conditions.
 * Removed explicit cast from write functions.
 * Removed local variable val from rz_mtu3_count_ceiling_read()
 * Added lock for RMW for counter/ceiling updates.
 * Added different synapses for counter0 and counter{1,2}
 * Used ARRAY for assigning num_counts.
 * Added PM runtime for managing clocks.
 * Add MODULE_IMPORT_NS(COUNTER) to import the COUNTER namespace.
---
 drivers/counter/Kconfig       |  11 +
 drivers/counter/Makefile      |   1 +
 drivers/counter/rz-mtu3-cnt.c | 847 ++++++++++++++++++++++++++++++++++
 3 files changed, 859 insertions(+)
 create mode 100644 drivers/counter/rz-mtu3-cnt.c

Comments

William Breathitt Gray Dec. 16, 2022, 4:01 p.m. UTC | #1
On Wed, Dec 14, 2022 at 10:31:35AM +0000, Biju Das wrote:
> Add RZ/G2L MTU3a counter driver. This IP supports the following
> phase counting modes on MTU1 and MTU2 channels
> 
> 1) 16-bit phase counting modes on MTU1 and MTU2 channels.
> 2) 32-bit phase counting mode by cascading MTU1 and MTU2 channels.
> 
> This patch adds 3 counter value channels.
> 	count0: 16-bit phase counter value channel on MTU1
> 	count1: 16-bit phase counter value channel on MTU2
> 	count2: 32-bit phase counter value channel by cascading
>                 MTU1 and MTU2 channels.
> 
> The external input phase clock pin for the counter value channels
> are as follows:
> 	count0: "MTCLKA-MTCLKB"
> 	count1: "MTCLKA-MTCLKB" or "MTCLKC-MTCLKD"
> 	count2: "MTCLKA-MTCLKB" or "MTCLKC-MTCLKD"
> 
> Use the sysfs variable "external_input_phase_clock_select" to select the
> external input phase clock pin and "cascade_counts_enable" to enable/
> disable cascading of channels.
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>

Hello Biju,

Do you need to take the ch->lock before checking ch->is_busy to ensure
it does not change?

Regardless, I have some race comments below.

> +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);
> +	u8 timer_mode;
> +
> +	if (ch->is_busy && !priv->count_is_enabled[count->id])
> +		return -EINVAL;

The priv->lock must be taken because count_is_enabled could change
after it's checked here.

However, you'll need to spin up a helper function because you're
currently calling rz_mtu3_count_function_read() in
rz_mtu3_action_read(). So move the implementation of this function to a
new helper function and call that here with the appropriate locks.

> +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);
> +	u8 tsr;
> +
> +	if (ch->is_busy && !priv->count_is_enabled[count->id])
> +		return -EINVAL;

This needs to be locked for the same reason as above.

William Breathitt Gray
Biju Das Dec. 16, 2022, 5 p.m. UTC | #2
Hi William Breathitt Gray,

> Subject: Re: [PATCH v9 4/5] counter: Add Renesas RZ/G2L MTU3a counter driver
> 
> On Wed, Dec 14, 2022 at 10:31:35AM +0000, Biju Das wrote:
> > Add RZ/G2L MTU3a counter driver. This IP supports the following phase
> > counting modes on MTU1 and MTU2 channels
> >
> > 1) 16-bit phase counting modes on MTU1 and MTU2 channels.
> > 2) 32-bit phase counting mode by cascading MTU1 and MTU2 channels.
> >
> > This patch adds 3 counter value channels.
> > 	count0: 16-bit phase counter value channel on MTU1
> > 	count1: 16-bit phase counter value channel on MTU2
> > 	count2: 32-bit phase counter value channel by cascading
> >                 MTU1 and MTU2 channels.
> >
> > The external input phase clock pin for the counter value channels are
> > as follows:
> > 	count0: "MTCLKA-MTCLKB"
> > 	count1: "MTCLKA-MTCLKB" or "MTCLKC-MTCLKD"
> > 	count2: "MTCLKA-MTCLKB" or "MTCLKC-MTCLKD"
> >
> > Use the sysfs variable "external_input_phase_clock_select" to select
> > the external input phase clock pin and "cascade_counts_enable" to
> > enable/ disable cascading of channels.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> 
> Hello Biju,
> 
> Do you need to take the ch->lock before checking ch->is_busy to ensure it
> does not change?

priv->count_is_enabled[count->id]-> true means channel is held by counter.
So pwm won't be able to change the state ch->is_busy.

priv->count_is_enabled[count->id]-> false and if there is contention for ch->busy
whoever is first calling rz_mtu3_request_channel() will get the channel.
among pwm_request and counter_enable.

So I think it is safe here. Please correct me if I am missing something.

static inline bool rz_mtu3_request_channel(struct rz_mtu3_channel *ch)
{
	bool is_idle;

	mutex_lock(&ch->lock);
	is_idle = !ch->is_busy;
	if (is_idle)
		ch->is_busy = true;
	mutex_unlock(&ch->lock);

	return is_idle;
}

> 
> Regardless, I have some race comments below.
> 
> > +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);
> > +	u8 timer_mode;
> > +
> > +	if (ch->is_busy && !priv->count_is_enabled[count->id])
> > +		return -EINVAL;
> 

The above check is for avoiding race between pwm and counter.

> The priv->lock must be taken because count_is_enabled could change after
> it's checked here.

OK, Will add priv->lock.

> 
> However, you'll need to spin up a helper function because you're currently
> calling rz_mtu3_count_function_read() in rz_mtu3_action_read(). So move the
> implementation of this function to a new helper function and call that here
> with the appropriate locks.

OK. Will add helper function.

> 
> > +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);
> > +	u8 tsr;
> > +
> > +	if (ch->is_busy && !priv->count_is_enabled[count->id])
> > +		return -EINVAL;
> 
> This needs to be locked for the same reason as above.

Agreed.

Cheers,
Biju
William Breathitt Gray Dec. 16, 2022, 5:13 p.m. UTC | #3
On Fri, Dec 16, 2022 at 05:00:30PM +0000, Biju Das wrote:
> > Hello Biju,
> > 
> > Do you need to take the ch->lock before checking ch->is_busy to ensure it
> > does not change?
> 
> priv->count_is_enabled[count->id]-> true means channel is held by counter.
> So pwm won't be able to change the state ch->is_busy.
> 
> priv->count_is_enabled[count->id]-> false and if there is contention for ch->busy
> whoever is first calling rz_mtu3_request_channel() will get the channel.
> among pwm_request and counter_enable.
> 
> So I think it is safe here. Please correct me if I am missing something.
> 
> static inline bool rz_mtu3_request_channel(struct rz_mtu3_channel *ch)
> {
> 	bool is_idle;
> 
> 	mutex_lock(&ch->lock);
> 	is_idle = !ch->is_busy;
> 	if (is_idle)
> 		ch->is_busy = true;
> 	mutex_unlock(&ch->lock);
> 
> 	return is_idle;
> }

Okay seems safe then. If the respective count_is_enabled will only be
true when the respective channel is held by the counter, is there a need
to check ch->is_busy, or would checking count_is_enabled alone suffice?

William Breathitt Gray
Biju Das Dec. 16, 2022, 5:24 p.m. UTC | #4
Hi William Breathitt Gray,

> Subject: Re: [PATCH v9 4/5] counter: Add Renesas RZ/G2L MTU3a counter driver
> 
> On Fri, Dec 16, 2022 at 05:00:30PM +0000, Biju Das wrote:
> > > Hello Biju,
> > >
> > > Do you need to take the ch->lock before checking ch->is_busy to
> > > ensure it does not change?
> >
> > priv->count_is_enabled[count->id]-> true means channel is held by counter.
> > So pwm won't be able to change the state ch->is_busy.
> >
> > priv->count_is_enabled[count->id]-> false and if there is contention
> > priv->for ch->busy
> > whoever is first calling rz_mtu3_request_channel() will get the channel.
> > among pwm_request and counter_enable.
> >
> > So I think it is safe here. Please correct me if I am missing something.
> >
> > static inline bool rz_mtu3_request_channel(struct rz_mtu3_channel *ch)
> > {
> > 	bool is_idle;
> >
> > 	mutex_lock(&ch->lock);
> > 	is_idle = !ch->is_busy;
> > 	if (is_idle)
> > 		ch->is_busy = true;
> > 	mutex_unlock(&ch->lock);
> >
> > 	return is_idle;
> > }
> 
> Okay seems safe then. If the respective count_is_enabled will only be true
> when the respective channel is held by the counter, is there a need to check
> ch->is_busy, or would checking count_is_enabled alone suffice?

We still can configure below properties before enabling the count.
That can be done only when ch->is_busy = false or ch->is_busy= true and count_is_enabled.
That is channel is used by the counter.

/sys/bus/counter/devices/counterX/external_input_phase_clock_select
/sys/bus/counter/devices/counterX/long_word_access_ctrl_mode
/sys/bus/counter/devices/counterX/count2/count
/sys/bus/counter/devices/counterX/count2/ceiling

Cheers,
Biju
William Breathitt Gray Dec. 16, 2022, 5:34 p.m. UTC | #5
On Fri, Dec 16, 2022 at 05:24:02PM +0000, Biju Das wrote:
> Hi William Breathitt Gray,
> 
> > Subject: Re: [PATCH v9 4/5] counter: Add Renesas RZ/G2L MTU3a counter driver
> > 
> > On Fri, Dec 16, 2022 at 05:00:30PM +0000, Biju Das wrote:
> > > > Hello Biju,
> > > >
> > > > Do you need to take the ch->lock before checking ch->is_busy to
> > > > ensure it does not change?
> > >
> > > priv->count_is_enabled[count->id]-> true means channel is held by counter.
> > > So pwm won't be able to change the state ch->is_busy.
> > >
> > > priv->count_is_enabled[count->id]-> false and if there is contention
> > > priv->for ch->busy
> > > whoever is first calling rz_mtu3_request_channel() will get the channel.
> > > among pwm_request and counter_enable.
> > >
> > > So I think it is safe here. Please correct me if I am missing something.
> > >
> > > static inline bool rz_mtu3_request_channel(struct rz_mtu3_channel *ch)
> > > {
> > > 	bool is_idle;
> > >
> > > 	mutex_lock(&ch->lock);
> > > 	is_idle = !ch->is_busy;
> > > 	if (is_idle)
> > > 		ch->is_busy = true;
> > > 	mutex_unlock(&ch->lock);
> > >
> > > 	return is_idle;
> > > }
> > 
> > Okay seems safe then. If the respective count_is_enabled will only be true
> > when the respective channel is held by the counter, is there a need to check
> > ch->is_busy, or would checking count_is_enabled alone suffice?
> 
> We still can configure below properties before enabling the count.
> That can be done only when ch->is_busy = false or ch->is_busy= true and count_is_enabled.
> That is channel is used by the counter.
> 
> /sys/bus/counter/devices/counterX/external_input_phase_clock_select
> /sys/bus/counter/devices/counterX/long_word_access_ctrl_mode
> /sys/bus/counter/devices/counterX/count2/count
> /sys/bus/counter/devices/counterX/count2/ceiling
> 
> Cheers,
> Biju

I see what you mean now, we'll need to check ch->is_busy regardless and
not just the count_is_enable state. That should be fine then, thanks for
explaining.

William Breathitt Gray
diff mbox series

Patch

diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index d388bf26f4dc..daa352c7392d 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -39,6 +39,17 @@  config INTERRUPT_CNT
 	  To compile this driver as a module, choose M here: the
 	  module will be called interrupt-cnt.
 
+config RZ_MTU3_CNT
+	tristate "Renesas RZ/G2L MTU3a counter driver"
+	depends on RZ_MTU3 || COMPILE_TEST
+	help
+	  Enable support for MTU3a counter driver found on Renesas RZ/G2L alike
+	  SoCs. This IP supports both 16-bit and 32-bit phase counting mode
+	  support.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rz-mtu3-cnt.
+
 config STM32_TIMER_CNT
 	tristate "STM32 Timer encoder counter driver"
 	depends on MFD_STM32_TIMERS || COMPILE_TEST
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index b9a369e0d4fc..933fdd50b3e4 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -8,6 +8,7 @@  counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
 
 obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
 obj-$(CONFIG_INTERRUPT_CNT)		+= interrupt-cnt.o
+obj-$(CONFIG_RZ_MTU3_CNT)	+= rz-mtu3-cnt.o
 obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
 obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o
 obj-$(CONFIG_TI_EQEP)		+= ti-eqep.o
diff --git a/drivers/counter/rz-mtu3-cnt.c b/drivers/counter/rz-mtu3-cnt.c
new file mode 100644
index 000000000000..2cc8cc6d8799
--- /dev/null
+++ b/drivers/counter/rz-mtu3-cnt.c
@@ -0,0 +1,847 @@ 
+// 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/types.h>
+
+#include <clocksource/rz-mtu3.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_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);
+
+	mutex_lock(&priv->lock);
+	if (ch->is_busy && !priv->count_is_enabled[count->id]) {
+		mutex_unlock(&priv->lock);
+		return -EINVAL;
+	}
+
+	if (rz_mtu3_is_counter_invalid(counter, count->id)) {
+		mutex_unlock(&priv->lock);
+		return -EBUSY;
+	}
+
+	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);
+
+	mutex_lock(&priv->lock);
+	if (ch->is_busy && !priv->count_is_enabled[count->id]) {
+		mutex_unlock(&priv->lock);
+		return -EINVAL;
+	}
+
+	if (rz_mtu3_is_counter_invalid(counter, count->id)) {
+		mutex_unlock(&priv->lock);
+		return -EBUSY;
+	}
+
+	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(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;
+
+	if (ch->is_busy && !priv->count_is_enabled[count->id])
+		return -EINVAL;
+
+	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_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;
+
+	mutex_lock(&priv->lock);
+	if (ch->is_busy && !priv->count_is_enabled[count->id]) {
+		mutex_unlock(&priv->lock);
+		return -EINVAL;
+	}
+
+	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);
+	u8 tsr;
+
+	if (ch->is_busy && !priv->count_is_enabled[count->id])
+		return -EINVAL;
+
+	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;
+
+	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);
+
+	mutex_lock(&priv->lock);
+	if (ch->is_busy && !priv->count_is_enabled[count->id]) {
+		mutex_unlock(&priv->lock);
+		return -EINVAL;
+	}
+
+	if (rz_mtu3_is_counter_invalid(counter, count->id)) {
+		mutex_unlock(&priv->lock);
+		return -EBUSY;
+	}
+
+	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);
+
+	mutex_lock(&priv->lock);
+	if (ch->is_busy && !priv->count_is_enabled[count->id]) {
+		mutex_unlock(&priv->lock);
+		return -EINVAL;
+	}
+
+	if (rz_mtu3_is_counter_invalid(counter, count->id)) {
+		mutex_unlock(&priv->lock);
+		return -EBUSY;
+	}
+
+	switch (count->id) {
+	case RZ_MTU3_16_BIT_MTU1_CH:
+	case RZ_MTU3_16_BIT_MTU2_CH:
+		if (ceiling > U16_MAX)
+			return -ERANGE;
+		priv->mtu_16bit_max[ch_id] = ceiling;
+		break;
+	case RZ_MTU3_32_BIT_CH:
+		if (ceiling > U32_MAX)
+			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);
+
+	mutex_lock(&priv->lock);
+	if (ch->is_busy && !priv->count_is_enabled[count->id]) {
+		mutex_unlock(&priv->lock);
+		return -EINVAL;
+	}
+
+	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) {
+		pm_runtime_get_sync(ch->dev);
+		mutex_lock(&priv->lock);
+		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;
+		mutex_unlock(&priv->lock);
+		pm_runtime_put(ch->dev);
+	}
+
+	return ret;
+}
+
+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;
+
+	pm_runtime_get_sync(priv->ch->dev);
+	mutex_lock(&priv->lock);
+	tmdr = rz_mtu3_shared_reg_read(priv->ch, RZ_MTU3_TMDR3);
+	*cascade_enable = test_bit(RZ_MTU3_TMDR3_LWA, &tmdr);
+	mutex_unlock(&priv->lock);
+	pm_runtime_put(priv->ch->dev);
+
+	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);
+
+	pm_runtime_get_sync(priv->ch->dev);
+	mutex_lock(&priv->lock);
+	rz_mtu3_shared_reg_update_bit(priv->ch, RZ_MTU3_TMDR3,
+				      RZ_MTU3_TMDR3_LWA, cascade_enable);
+	mutex_unlock(&priv->lock);
+	pm_runtime_put(priv->ch->dev);
+
+	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;
+
+	pm_runtime_get_sync(priv->ch->dev);
+	mutex_lock(&priv->lock);
+	tmdr = rz_mtu3_shared_reg_read(priv->ch, RZ_MTU3_TMDR3);
+	*ext_input_phase_clock_select = test_bit(RZ_MTU3_TMDR3_PHCKSEL, &tmdr);
+	mutex_unlock(&priv->lock);
+	pm_runtime_put(priv->ch->dev);
+
+	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);
+
+	pm_runtime_get_sync(priv->ch->dev);
+	mutex_lock(&priv->lock);
+	rz_mtu3_shared_reg_update_bit(priv->ch, RZ_MTU3_TMDR3,
+				      RZ_MTU3_TMDR3_PHCKSEL,
+				      ext_input_phase_clock_select);
+	mutex_unlock(&priv->lock);
+	pm_runtime_put(priv->ch->dev);
+
+	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_cnt *const priv = counter_priv(counter);
+	enum counter_function function;
+	bool mtclkc_mtclkd;
+	unsigned long tmdr;
+	int err;
+
+	mutex_lock(&priv->lock);
+	err = rz_mtu3_count_function_read(counter, count, &function);
+	if (err) {
+		mutex_unlock(&priv->lock);
+		return err;
+	}
+
+	/* 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 (combined) 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_MTU1];
+	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);