drivers/ps2/ps2_npcx_controller.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 2021 Nuvoton Technology Corporation.
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 #define DT_DRV_COMPAT nuvoton_npcx_ps2_ctrl

 /**
  * @file
  * @brief Nuvoton NPCX PS/2 module (controller) driver
  *
  * This file contains the driver of PS/2 module (controller) which provides a
  * hardware accelerator mechanism to handle both incoming and outgoing data.
  * The hardware accelerator mechanism is shared by four PS/2 channels.
  */

 #include <zephyr/drivers/clock_control.h>
 #include <zephyr/drivers/ps2.h>
 #include <zephyr/dt-bindings/clock/npcx_clock.h>

 #include <zephyr/logging/log.h>
 #include <zephyr/irq.h>
 LOG_MODULE_REGISTER(ps2_npcx_ctrl, CONFIG_PS2_LOG_LEVEL);

 #define NPCX_PS2_CH_COUNT 4

 /*
  * Set WDAT3-0 and clear CLK3-0 in the PSOSIG register to
  * reset the shift mechanism.
  */
 #define NPCX_PS2_SHIFT_MECH_RESET (uint8_t)~NPCX_PSOSIG_CLK_MASK_ALL

 /* in 50us units */
 #define PS2_RETRY_COUNT 10000

 /*
  * The max duration of a PS/2 clock is about 100 micro-seconds.
  * A PS/2 transaction needs 11 clock cycles. It will take about 1.1 ms for a
  * complete transaction.
  */
 #define PS2_TRANSACTION_TIMEOUT K_MSEC(2)

 /* Device config */
 struct ps2_npcx_ctrl_config {
 	uintptr_t base;
 	struct npcx_clk_cfg clk_cfg;
 };

 /* Driver data */
 struct ps2_npcx_ctrl_data {
 	/*
 	 * Bit mask to record the enabled PS/2 channels.
 	 * Only bit[7] and bit[5:3] are used
 	 * (i.e. the bit position of CLK3-0 in the PS2_PSOSIG register)
 	 */
 	uint8_t channel_enabled_mask;
 	/* The mutex of the PS/2 controller */
 	struct k_sem lock;
 	/* The semaphore to synchronize the Tx transaction */
 	struct k_sem tx_sync_sem;
 	/*
 	 * The callback function to handle the data received from PS/2 device
 	 */
 	ps2_callback_t callback_isr[NPCX_PS2_CH_COUNT];
 };

 /* Driver convenience defines */
 #define HAL_PS2_INSTANCE(dev)                                                                      \
 	((struct ps2_reg *)((const struct ps2_npcx_ctrl_config *)(dev)->config)->base)

 static uint8_t ps2_npcx_ctrl_get_ch_clk_mask(uint8_t channel_id)
 {
 	return BIT(NPCX_PSOSIG_CLK(channel_id));
 }

 int ps2_npcx_ctrl_configure(const struct device *dev, uint8_t channel_id,
 			    ps2_callback_t callback_isr)
 {
 	struct ps2_npcx_ctrl_data *const data = dev->data;

 	if (channel_id >= NPCX_PS2_CH_COUNT) {
 		LOG_ERR("unexpected channel ID: %d", channel_id);
 		return -EINVAL;
 	}

 	if (callback_isr == NULL) {
 		return -EINVAL;
 	}

 	k_sem_take(&data->lock, K_FOREVER);
 	data->callback_isr[channel_id] = callback_isr;
 	k_sem_give(&data->lock);

 	return 0;
 }

 int ps2_npcx_ctrl_enable_interface(const struct device *dev, uint8_t channel_id,
 				   bool enable)
 {
 	struct ps2_npcx_ctrl_data *const data = dev->data;
 	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
 	uint8_t ch_clk_mask;

 	k_sem_take(&data->lock, K_FOREVER);
 	/*
 	 * Disable the interrupt during changing the enabled channel mask to
 	 * prevent from preemption.
 	 */
 	irq_disable(DT_INST_IRQN(0));

 	if (channel_id >= NPCX_PS2_CH_COUNT) {
 		LOG_ERR("unexpected channel ID: %d", channel_id);
 		irq_enable(DT_INST_IRQN(0));
 		k_sem_give(&data->lock);
 		return -EINVAL;
 	}

 	ch_clk_mask = ps2_npcx_ctrl_get_ch_clk_mask(channel_id);
 	if (enable) {
 		data->channel_enabled_mask |= ch_clk_mask;
 		/* Enable the relevant channel clock */
 		inst->PSOSIG |= ch_clk_mask;
 	} else {
 		data->channel_enabled_mask &= ~ch_clk_mask;
 		/* Disable the relevant channel clock */
 		inst->PSOSIG &= ~ch_clk_mask;
 	}

 	irq_enable(DT_INST_IRQN(0));
 	k_sem_give(&data->lock);

 	return 0;
 }

 static int ps2_npcx_ctrl_bus_busy(const struct device *dev)
 {
 	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);

 	/*
 	 * The driver pulls the CLK for non-active channels to low when Start
 	 * bit is detected and pull the CLK of the active channel low after
 	 * Stop bit detected. The EOT bit is set when Stop bit is detected,
 	 * but both SOT and EOT are cleared when all CLKs are pull low
 	 * (due to Shift Mechanism is reset)
 	 */
 	return (IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_SOT) ||
 		IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_EOT)) ?
 		       -EBUSY :
 		       0;
 }

 int ps2_npcx_ctrl_write(const struct device *dev, uint8_t channel_id,
 			uint8_t value)
 {
 	struct ps2_npcx_ctrl_data *const data = dev->data;
 	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
 	int i = 0;

 	if (channel_id >= NPCX_PS2_CH_COUNT) {
 		LOG_ERR("unexpected channel ID: %d", channel_id);
 		return -EINVAL;
 	}

 	if (!(ps2_npcx_ctrl_get_ch_clk_mask(channel_id) &
 	      data->channel_enabled_mask)) {
 		LOG_ERR("channel %d is not enabled", channel_id);
 		return -EINVAL;
 	}

 	k_sem_take(&data->lock, K_FOREVER);

 	while (ps2_npcx_ctrl_bus_busy(dev) && (i < PS2_RETRY_COUNT)) {
 		k_busy_wait(50);
 		i++;
 	}

 	if (unlikely(i == PS2_RETRY_COUNT)) {
 		LOG_ERR("PS2 write attempt timed out");
 		goto timeout_invalid;
 	}

 	/* Set PS/2 in transmit mode */
 	inst->PSCON |= BIT(NPCX_PSCON_XMT);
 	/* Enable Start Of Transaction interrupt */
 	inst->PSIEN |= BIT(NPCX_PSIEN_SOTIE);

 	/* Reset the shift mechanism */
 	inst->PSOSIG = NPCX_PS2_SHIFT_MECH_RESET;
 	/* Inhibit communication should last at least 100 micro-seconds */
 	k_busy_wait(100);

 	/* Write the data to be transmitted */
 	inst->PSDAT = value;
 	/* Apply the Request-to-send */
 	inst->PSOSIG &= ~BIT(NPCX_PSOSIG_WDAT(channel_id));
 	inst->PSOSIG |= ps2_npcx_ctrl_get_ch_clk_mask(channel_id);
 	if (k_sem_take(&data->tx_sync_sem, PS2_TRANSACTION_TIMEOUT) != 0) {
 		irq_disable(DT_INST_IRQN(0));
 		LOG_ERR("PS/2 Tx timeout");
 		/* Reset the shift mechanism */
 		inst->PSOSIG = NPCX_PS2_SHIFT_MECH_RESET;
 		/* Change the PS/2 module to receive mode */
 		inst->PSCON &= ~BIT(NPCX_PSCON_XMT);
 		/*
 		 * Restore the channel back to enable according to
 		 * channel_enabled_mask.
 		 */
 		inst->PSOSIG |= data->channel_enabled_mask;
 		irq_enable(DT_INST_IRQN(0));
 		goto timeout_invalid;
 	}

 	k_sem_give(&data->lock);
 	return 0;

 timeout_invalid:
 	k_sem_give(&data->lock);
 	return -ETIMEDOUT;
 }

 static int ps2_npcx_ctrl_is_rx_error(const struct device *dev)
 {
 	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
 	uint8_t status;

 	status = inst->PSTAT & (BIT(NPCX_PSTAT_PERR) | BIT(NPCX_PSTAT_RFERR));
 	if (status) {
 		if (status & BIT(NPCX_PSTAT_PERR))
 			LOG_ERR("RX parity error");
 		if (status & BIT(NPCX_PSTAT_RFERR))
 			LOG_ERR("RX Frame error");
 		return -EIO;
 	}

 	return 0;
 }

 static void ps2_npcx_ctrl_isr(const struct device *dev)
 {
 	uint8_t active_ch, mask;
 	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
 	struct ps2_npcx_ctrl_data *const data = dev->data;

 	/*
 	 * ACH = 1 : Channel 0
 	 * ACH = 2 : Channel 1
 	 * ACH = 4 : Channel 2
 	 * ACH = 5 : Channel 3
 	 */
 	active_ch = GET_FIELD(inst->PSTAT, NPCX_PSTAT_ACH);
 	active_ch = active_ch > 2 ? (active_ch - 2) : (active_ch - 1);
 	LOG_DBG("ACH: %d\n", active_ch);

 	/*
 	 * Inhibit PS/2 transaction of the other non-active channels by
 	 * pulling down the clock signal
 	 */
 	mask = ~NPCX_PSOSIG_CLK_MASK_ALL | BIT(NPCX_PSOSIG_CLK(active_ch));
 	inst->PSOSIG &= mask;

 	/* PS/2 Start of Transaction */
 	if (IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_SOT) &&
 	    IS_BIT_SET(inst->PSIEN, NPCX_PSIEN_SOTIE)) {
 		/*
 		 * Once set, SOT is not cleared until the shift mechanism
 		 * is reset. Therefore, SOTIE should be cleared on the
 		 * first occurrence of an SOT interrupt.
 		 */
 		inst->PSIEN &= ~BIT(NPCX_PSIEN_SOTIE);
 		LOG_DBG("SOT");
 		/* PS/2 End of Transaction */
 	} else if (IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_EOT)) {
 		inst->PSIEN &= ~BIT(NPCX_PSIEN_EOTIE);

 		/*
 		 * Clear the CLK of active channel to reset
 		 * the shift mechanism
 		 */
 		inst->PSOSIG &= ~BIT(NPCX_PSOSIG_CLK(active_ch));

 		/* Tx is done */
 		if (IS_BIT_SET(inst->PSCON, NPCX_PSCON_XMT)) {
 			/* Change the PS/2 module to receive mode */
 			inst->PSCON &= ~BIT(NPCX_PSCON_XMT);
 			k_sem_give(&data->tx_sync_sem);
 		} else {
 			if (ps2_npcx_ctrl_is_rx_error(dev) == 0) {
 				ps2_callback_t callback;
 				uint8_t data_in = inst->PSDAT;

 				LOG_DBG("Recv:0x%02x", data_in);
 				callback = data->callback_isr[active_ch];
 				if (callback != NULL) {
 					callback(dev, data_in);
 				}
 			}
 		}

 		/* Restore the enabled channel */
 		inst->PSOSIG |= data->channel_enabled_mask;
 		/*
 		 * Re-enable the Start Of Transaction interrupt when
 		 * the shift mechanism is reset
 		 */
 		inst->PSIEN |= BIT(NPCX_PSIEN_SOTIE);
 		inst->PSIEN |= BIT(NPCX_PSIEN_EOTIE);
 		LOG_DBG("EOT");
 	}
 }

 /* PS/2 driver registration */
 static int ps2_npcx_ctrl_init(const struct device *dev);

 static struct ps2_npcx_ctrl_data ps2_npcx_ctrl_data_0;

 static const struct ps2_npcx_ctrl_config ps2_npcx_ctrl_config_0 = {
 	.base = DT_INST_REG_ADDR(0),
 	.clk_cfg = NPCX_DT_CLK_CFG_ITEM(0),
 };

 DEVICE_DT_INST_DEFINE(0, &ps2_npcx_ctrl_init, NULL, &ps2_npcx_ctrl_data_0,
 		      &ps2_npcx_ctrl_config_0, POST_KERNEL,
 		      CONFIG_PS2_INIT_PRIORITY, NULL);

 static int ps2_npcx_ctrl_init(const struct device *dev)
 {
 	const struct ps2_npcx_ctrl_config *const config = dev->config;
 	struct ps2_npcx_ctrl_data *const data = dev->data;
 	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
 	const struct device *const clk_dev = DEVICE_DT_GET(NPCX_CLK_CTRL_NODE);
 	int ret;

 	if (!device_is_ready(clk_dev)) {
 		LOG_ERR("%s device not ready", clk_dev->name);
 		return -ENODEV;
 	}

 	/* Turn on PS/2 controller device clock */
 	ret = clock_control_on(clk_dev,
 			       (clock_control_subsys_t)&config->clk_cfg);
 	if (ret < 0) {
 		LOG_ERR("Turn on PS/2 clock fail %d", ret);
 		return ret;
 	}

 	/* Disable shift mechanism and configure PS/2 to received mode. */
 	inst->PSCON = 0x0;
 	/* Set WDAT3-0 and clear CLK3-0 before enabling shift mechanism */
 	inst->PSOSIG = NPCX_PS2_SHIFT_MECH_RESET;
 	/*
 	 * PS/2 interrupt enable register
 	 * [0] - : SOTIE   = 1: Start Of Transaction Interrupt Enable
 	 * [1] - : EOTIE   = 1: End Of Transaction Interrupt Enable
 	 * [4] - : WUE     = 1: Wake-Up Enable
 	 * [7] - : CLK_SEL = 1: Select Free-Run clock as the basic clock
 	 *                   0: Select APB1 clock as the basic clock
 	 */
 	inst->PSIEN = BIT(NPCX_PSIEN_SOTIE) | BIT(NPCX_PSIEN_EOTIE) |
 		      BIT(NPCX_PSIEN_PS2_WUE);
 	if (config->clk_cfg.bus == NPCX_CLOCK_BUS_FREERUN)
 		inst->PSIEN |= BIT(NPCX_PSIEN_PS2_CLK_SEL);
 	/* Enable weak internal pull-up */
 	inst->PSCON |= BIT(NPCX_PSCON_WPUED);
 	/* Enable shift mechanism */
 	inst->PSCON |= BIT(NPCX_PSCON_EN);

 	k_sem_init(&data->lock, 1, 1);
 	k_sem_init(&data->tx_sync_sem, 0, 1);

 	IRQ_CONNECT(DT_INST_IRQN(0), DT_INST_IRQ(0, priority),
 		    ps2_npcx_ctrl_isr, DEVICE_DT_INST_GET(0), 0);

 	irq_enable(DT_INST_IRQN(0));

 	return 0;
 }
	/*
	* Copyright (c) 2021 Nuvoton Technology Corporation.
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	#define DT_DRV_COMPAT nuvoton_npcx_ps2_ctrl

	/**
	* @file
	* @brief Nuvoton NPCX PS/2 module (controller) driver
	*
	* This file contains the driver of PS/2 module (controller) which provides a
	* hardware accelerator mechanism to handle both incoming and outgoing data.
	* The hardware accelerator mechanism is shared by four PS/2 channels.
	*/

	#include <zephyr/drivers/clock_control.h>
	#include <zephyr/drivers/ps2.h>
	#include <zephyr/dt-bindings/clock/npcx_clock.h>

	#include <zephyr/logging/log.h>
	#include <zephyr/irq.h>
	LOG_MODULE_REGISTER(ps2_npcx_ctrl, CONFIG_PS2_LOG_LEVEL);

	#define NPCX_PS2_CH_COUNT 4

	/*
	* Set WDAT3-0 and clear CLK3-0 in the PSOSIG register to
	* reset the shift mechanism.
	*/
	#define NPCX_PS2_SHIFT_MECH_RESET (uint8_t)~NPCX_PSOSIG_CLK_MASK_ALL

	/* in 50us units */
	#define PS2_RETRY_COUNT 10000

	/*
	* The max duration of a PS/2 clock is about 100 micro-seconds.
	* A PS/2 transaction needs 11 clock cycles. It will take about 1.1 ms for a
	* complete transaction.
	*/
	#define PS2_TRANSACTION_TIMEOUT K_MSEC(2)

	/* Device config */
	struct ps2_npcx_ctrl_config {
	uintptr_t base;
	struct npcx_clk_cfg clk_cfg;
	};

	/* Driver data */
	struct ps2_npcx_ctrl_data {
	/*
	* Bit mask to record the enabled PS/2 channels.
	* Only bit[7] and bit[5:3] are used
	* (i.e. the bit position of CLK3-0 in the PS2_PSOSIG register)
	*/
	uint8_t channel_enabled_mask;
	/* The mutex of the PS/2 controller */
	struct k_sem lock;
	/* The semaphore to synchronize the Tx transaction */
	struct k_sem tx_sync_sem;
	/*
	* The callback function to handle the data received from PS/2 device
	*/
	ps2_callback_t callback_isr[NPCX_PS2_CH_COUNT];
	};

	/* Driver convenience defines */
	#define HAL_PS2_INSTANCE(dev) \
	((struct ps2_reg )((const struct ps2_npcx_ctrl_config )(dev)->config)->base)

	static uint8_t ps2_npcx_ctrl_get_ch_clk_mask(uint8_t channel_id)
	{
	return BIT(NPCX_PSOSIG_CLK(channel_id));
	}

	int ps2_npcx_ctrl_configure(const struct device *dev, uint8_t channel_id,
	ps2_callback_t callback_isr)
	{
	struct ps2_npcx_ctrl_data *const data = dev->data;

	if (channel_id >= NPCX_PS2_CH_COUNT) {
	LOG_ERR("unexpected channel ID: %d", channel_id);
	return -EINVAL;
	}

	if (callback_isr == NULL) {
	return -EINVAL;
	}

	k_sem_take(&data->lock, K_FOREVER);
	data->callback_isr[channel_id] = callback_isr;
	k_sem_give(&data->lock);

	return 0;
	}

	int ps2_npcx_ctrl_enable_interface(const struct device *dev, uint8_t channel_id,
	bool enable)
	{
	struct ps2_npcx_ctrl_data *const data = dev->data;
	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
	uint8_t ch_clk_mask;

	k_sem_take(&data->lock, K_FOREVER);
	/*
	* Disable the interrupt during changing the enabled channel mask to
	* prevent from preemption.
	*/
	irq_disable(DT_INST_IRQN(0));

	if (channel_id >= NPCX_PS2_CH_COUNT) {
	LOG_ERR("unexpected channel ID: %d", channel_id);
	irq_enable(DT_INST_IRQN(0));
	k_sem_give(&data->lock);
	return -EINVAL;
	}

	ch_clk_mask = ps2_npcx_ctrl_get_ch_clk_mask(channel_id);
	if (enable) {
	data->channel_enabled_mask \|= ch_clk_mask;
	/* Enable the relevant channel clock */
	inst->PSOSIG \|= ch_clk_mask;
	} else {
	data->channel_enabled_mask &= ~ch_clk_mask;
	/* Disable the relevant channel clock */
	inst->PSOSIG &= ~ch_clk_mask;
	}

	irq_enable(DT_INST_IRQN(0));
	k_sem_give(&data->lock);

	return 0;
	}

	static int ps2_npcx_ctrl_bus_busy(const struct device *dev)
	{
	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);

	/*
	* The driver pulls the CLK for non-active channels to low when Start
	* bit is detected and pull the CLK of the active channel low after
	* Stop bit detected. The EOT bit is set when Stop bit is detected,
	* but both SOT and EOT are cleared when all CLKs are pull low
	* (due to Shift Mechanism is reset)
	*/
	return (IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_SOT) \|\|
	IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_EOT)) ?
	-EBUSY :
	0;
	}

	int ps2_npcx_ctrl_write(const struct device *dev, uint8_t channel_id,
	uint8_t value)
	{
	struct ps2_npcx_ctrl_data *const data = dev->data;
	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
	int i = 0;

	if (channel_id >= NPCX_PS2_CH_COUNT) {
	LOG_ERR("unexpected channel ID: %d", channel_id);
	return -EINVAL;
	}

	if (!(ps2_npcx_ctrl_get_ch_clk_mask(channel_id) &
	data->channel_enabled_mask)) {
	LOG_ERR("channel %d is not enabled", channel_id);
	return -EINVAL;
	}

	k_sem_take(&data->lock, K_FOREVER);

	while (ps2_npcx_ctrl_bus_busy(dev) && (i < PS2_RETRY_COUNT)) {
	k_busy_wait(50);
	i++;
	}

	if (unlikely(i == PS2_RETRY_COUNT)) {
	LOG_ERR("PS2 write attempt timed out");
	goto timeout_invalid;
	}

	/* Set PS/2 in transmit mode */
	inst->PSCON \|= BIT(NPCX_PSCON_XMT);
	/* Enable Start Of Transaction interrupt */
	inst->PSIEN \|= BIT(NPCX_PSIEN_SOTIE);

	/* Reset the shift mechanism */
	inst->PSOSIG = NPCX_PS2_SHIFT_MECH_RESET;
	/* Inhibit communication should last at least 100 micro-seconds */
	k_busy_wait(100);

	/* Write the data to be transmitted */
	inst->PSDAT = value;
	/* Apply the Request-to-send */
	inst->PSOSIG &= ~BIT(NPCX_PSOSIG_WDAT(channel_id));
	inst->PSOSIG \|= ps2_npcx_ctrl_get_ch_clk_mask(channel_id);
	if (k_sem_take(&data->tx_sync_sem, PS2_TRANSACTION_TIMEOUT) != 0) {
	irq_disable(DT_INST_IRQN(0));
	LOG_ERR("PS/2 Tx timeout");
	/* Reset the shift mechanism */
	inst->PSOSIG = NPCX_PS2_SHIFT_MECH_RESET;
	/* Change the PS/2 module to receive mode */
	inst->PSCON &= ~BIT(NPCX_PSCON_XMT);
	/*
	* Restore the channel back to enable according to
	* channel_enabled_mask.
	*/
	inst->PSOSIG \|= data->channel_enabled_mask;
	irq_enable(DT_INST_IRQN(0));
	goto timeout_invalid;
	}

	k_sem_give(&data->lock);
	return 0;

	timeout_invalid:
	k_sem_give(&data->lock);
	return -ETIMEDOUT;
	}

	static int ps2_npcx_ctrl_is_rx_error(const struct device *dev)
	{
	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
	uint8_t status;

	status = inst->PSTAT & (BIT(NPCX_PSTAT_PERR) \| BIT(NPCX_PSTAT_RFERR));
	if (status) {
	if (status & BIT(NPCX_PSTAT_PERR))
	LOG_ERR("RX parity error");
	if (status & BIT(NPCX_PSTAT_RFERR))
	LOG_ERR("RX Frame error");
	return -EIO;
	}

	return 0;
	}

	static void ps2_npcx_ctrl_isr(const struct device *dev)
	{
	uint8_t active_ch, mask;
	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
	struct ps2_npcx_ctrl_data *const data = dev->data;

	/*
	* ACH = 1 : Channel 0
	* ACH = 2 : Channel 1
	* ACH = 4 : Channel 2
	* ACH = 5 : Channel 3
	*/
	active_ch = GET_FIELD(inst->PSTAT, NPCX_PSTAT_ACH);
	active_ch = active_ch > 2 ? (active_ch - 2) : (active_ch - 1);
	LOG_DBG("ACH: %d\n", active_ch);

	/*
	* Inhibit PS/2 transaction of the other non-active channels by
	* pulling down the clock signal
	*/
	mask = ~NPCX_PSOSIG_CLK_MASK_ALL \| BIT(NPCX_PSOSIG_CLK(active_ch));
	inst->PSOSIG &= mask;

	/* PS/2 Start of Transaction */
	if (IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_SOT) &&
	IS_BIT_SET(inst->PSIEN, NPCX_PSIEN_SOTIE)) {
	/*
	* Once set, SOT is not cleared until the shift mechanism
	* is reset. Therefore, SOTIE should be cleared on the
	* first occurrence of an SOT interrupt.
	*/
	inst->PSIEN &= ~BIT(NPCX_PSIEN_SOTIE);
	LOG_DBG("SOT");
	/* PS/2 End of Transaction */
	} else if (IS_BIT_SET(inst->PSTAT, NPCX_PSTAT_EOT)) {
	inst->PSIEN &= ~BIT(NPCX_PSIEN_EOTIE);

	/*
	* Clear the CLK of active channel to reset
	* the shift mechanism
	*/
	inst->PSOSIG &= ~BIT(NPCX_PSOSIG_CLK(active_ch));

	/* Tx is done */
	if (IS_BIT_SET(inst->PSCON, NPCX_PSCON_XMT)) {
	/* Change the PS/2 module to receive mode */
	inst->PSCON &= ~BIT(NPCX_PSCON_XMT);
	k_sem_give(&data->tx_sync_sem);
	} else {
	if (ps2_npcx_ctrl_is_rx_error(dev) == 0) {
	ps2_callback_t callback;
	uint8_t data_in = inst->PSDAT;

	LOG_DBG("Recv:0x%02x", data_in);
	callback = data->callback_isr[active_ch];
	if (callback != NULL) {
	callback(dev, data_in);
	}
	}
	}

	/* Restore the enabled channel */
	inst->PSOSIG \|= data->channel_enabled_mask;
	/*
	* Re-enable the Start Of Transaction interrupt when
	* the shift mechanism is reset
	*/
	inst->PSIEN \|= BIT(NPCX_PSIEN_SOTIE);
	inst->PSIEN \|= BIT(NPCX_PSIEN_EOTIE);
	LOG_DBG("EOT");
	}
	}

	/* PS/2 driver registration */
	static int ps2_npcx_ctrl_init(const struct device *dev);

	static struct ps2_npcx_ctrl_data ps2_npcx_ctrl_data_0;

	static const struct ps2_npcx_ctrl_config ps2_npcx_ctrl_config_0 = {
	.base = DT_INST_REG_ADDR(0),
	.clk_cfg = NPCX_DT_CLK_CFG_ITEM(0),
	};

	DEVICE_DT_INST_DEFINE(0, &ps2_npcx_ctrl_init, NULL, &ps2_npcx_ctrl_data_0,
	&ps2_npcx_ctrl_config_0, POST_KERNEL,
	CONFIG_PS2_INIT_PRIORITY, NULL);

	static int ps2_npcx_ctrl_init(const struct device *dev)
	{
	const struct ps2_npcx_ctrl_config *const config = dev->config;
	struct ps2_npcx_ctrl_data *const data = dev->data;
	struct ps2_reg *const inst = HAL_PS2_INSTANCE(dev);
	const struct device *const clk_dev = DEVICE_DT_GET(NPCX_CLK_CTRL_NODE);
	int ret;

	if (!device_is_ready(clk_dev)) {
	LOG_ERR("%s device not ready", clk_dev->name);
	return -ENODEV;
	}

	/* Turn on PS/2 controller device clock */
	ret = clock_control_on(clk_dev,
	(clock_control_subsys_t)&config->clk_cfg);
	if (ret < 0) {
	LOG_ERR("Turn on PS/2 clock fail %d", ret);
	return ret;
	}

	/* Disable shift mechanism and configure PS/2 to received mode. */
	inst->PSCON = 0x0;
	/* Set WDAT3-0 and clear CLK3-0 before enabling shift mechanism */
	inst->PSOSIG = NPCX_PS2_SHIFT_MECH_RESET;
	/*
	* PS/2 interrupt enable register
	* [0] - : SOTIE = 1: Start Of Transaction Interrupt Enable
	* [1] - : EOTIE = 1: End Of Transaction Interrupt Enable
	* [4] - : WUE = 1: Wake-Up Enable
	* [7] - : CLK_SEL = 1: Select Free-Run clock as the basic clock
	* 0: Select APB1 clock as the basic clock
	*/
	inst->PSIEN = BIT(NPCX_PSIEN_SOTIE) \| BIT(NPCX_PSIEN_EOTIE) \|
	BIT(NPCX_PSIEN_PS2_WUE);
	if (config->clk_cfg.bus == NPCX_CLOCK_BUS_FREERUN)
	inst->PSIEN \|= BIT(NPCX_PSIEN_PS2_CLK_SEL);
	/* Enable weak internal pull-up */
	inst->PSCON \|= BIT(NPCX_PSCON_WPUED);
	/* Enable shift mechanism */
	inst->PSCON \|= BIT(NPCX_PSCON_EN);

	k_sem_init(&data->lock, 1, 1);
	k_sem_init(&data->tx_sync_sem, 0, 1);

	IRQ_CONNECT(DT_INST_IRQN(0), DT_INST_IRQ(0, priority),
	ps2_npcx_ctrl_isr, DEVICE_DT_INST_GET(0), 0);

	irq_enable(DT_INST_IRQN(0));

	return 0;
	}