drivers/gpio/gpio_intel_apl.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 2018-2019 Intel Corporation
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 /**
  * @file
  * @brief Intel Apollo Lake SoC GPIO Controller Driver
  *
  * The GPIO controller on Intel Apollo Lake SoC serves
  * both GPIOs and Pinmuxing function. This driver provides
  * the GPIO function.
  *
  * The GPIO controller has 245 pins divided into four sets.
  * Each set has its own MMIO address space. Due to GPIO
  * callback only allowing 32 pins (as a 32-bit mask) at once,
  * each set is further sub-divided into multiple devices, so
  * we export GPIO_INTEL_APL_NR_SUBDEVS devices to the kernel.
  */

 #define GPIO_INTEL_APL_NR_SUBDEVS 10

 #include <errno.h>
 #include <drivers/gpio.h>
 #include <soc.h>
 #include <sys/sys_io.h>
 #include <sys/__assert.h>
 #include <sys/slist.h>
 #include <sys/speculation.h>

 #include "gpio_utils.h"

 /*
  * only IRQ 14 is supported now. the docs say IRQ 15 is supported
  * as well, but my (admitted cursory) testing disagrees.
  */

 BUILD_ASSERT(DT_APL_GPIO_IRQ == 14);

 #define REG_PAD_BASE_ADDR		0x000C

 #define REG_MISCCFG			0x0010
 #define MISCCFG_IRQ_ROUTE_POS		3

 #define REG_PAD_OWNER_BASE		0x0020
 #define PAD_OWN_MASK			0x03
 #define PAD_OWN_HOST			0
 #define PAD_OWN_CSME			1
 #define PAD_OWN_ISH			2
 #define PAD_OWN_IE			3

 #define REG_PAD_HOST_SW_OWNER		0x0080
 #define PAD_HOST_SW_OWN_GPIO		1
 #define PAD_HOST_SW_OWN_ACPI		0

 #define REG_GPI_INT_STS_BASE		0x0100
 #define REG_GPI_INT_EN_BASE		0x0110

 #define PAD_CFG0_RXPADSTSEL		BIT(29)
 #define PAD_CFG0_RXRAW1			BIT(28)

 #define PAD_CFG0_PMODE_MASK		(0x0F << 10)

 #define PAD_CFG0_RXEVCFG_POS		25
 #define PAD_CFG0_RXEVCFG_MASK		(0x03 << PAD_CFG0_RXEVCFG_POS)
 #define PAD_CFG0_RXEVCFG_LEVEL		(0 << PAD_CFG0_RXEVCFG_POS)
 #define PAD_CFG0_RXEVCFG_EDGE		(1 << PAD_CFG0_RXEVCFG_POS)
 #define PAD_CFG0_RXEVCFG_DRIVE0		(2 << PAD_CFG0_RXEVCFG_POS)

 #define PAD_CFG0_PREGFRXSEL		BIT(24)
 #define PAD_CFG0_RXINV			BIT(23)

 #define PAD_CFG0_RXDIS			BIT(9)
 #define PAD_CFG0_TXDIS			BIT(8)
 #define PAD_CFG0_RXSTATE		BIT(1)
 #define PAD_CFG0_RXSTATE_POS		1
 #define PAD_CFG0_TXSTATE		BIT(0)
 #define PAD_CFG0_TXSTATE_POS		0

 #define PAD_CFG1_IOSTERM_POS		8
 #define PAD_CFG1_IOSTERM_MASK		(0x03 << PAD_CFG1_IOSTERM_POS)
 #define PAD_CFG1_IOSTERM_FUNC		(0 << PAD_CFG1_IOSTERM_POS)
 #define PAD_CFG1_IOSTERM_DISPUD		(1 << PAD_CFG1_IOSTERM_POS)
 #define PAD_CFG1_IOSTERM_PU		(2 << PAD_CFG1_IOSTERM_POS)
 #define PAD_CFG1_IOSTERM_PD		(3 << PAD_CFG1_IOSTERM_POS)

 #define PAD_CFG1_TERM_POS		10
 #define PAD_CFG1_TERM_MASK		(0x0F << PAD_CFG1_TERM_POS)
 #define PAD_CFG1_TERM_NONE		(0x00 << PAD_CFG1_TERM_POS)
 #define PAD_CFG1_TERM_PD		(0x04 << PAD_CFG1_TERM_POS)
 #define PAD_CFG1_TERM_PU		(0x0C << PAD_CFG1_TERM_POS)

 #define PAD_CFG1_IOSSTATE_POS		14
 #define PAD_CFG1_IOSSTATE_MASK		(0x0F << PAD_CFG1_IOSSTATE_POS)
 #define PAD_CFG1_IOSSTATE_IGNORE	(0x0F << PAD_CFG1_IOSSTATE_POS)

 struct gpio_intel_apl_config {
 	u32_t	reg_base;

 	u8_t	pin_offset;
 	u8_t	num_pins;
 };

 struct gpio_intel_apl_data {
 	/* Pad base address */
 	u32_t		pad_base;

 	sys_slist_t	cb;
 };

 #ifdef CONFIG_GPIO_INTEL_APL_CHECK_PERMS
 /**
  * @brief Check if host has permission to alter this GPIO pin.
  *
  * @param "struct device *dev" Device struct
  * @param "u32_t raw_pin" Raw GPIO pin
  *
  * @return true if host owns the GPIO pin, false otherwise
  */
 static bool check_perm(struct device *dev, u32_t raw_pin)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	struct gpio_intel_apl_data *data = dev->driver_data;
 	u32_t offset, val;

 	/* First is to establish that host software owns the pin */

 	/* read the Pad Ownership register related to the pin */
 	offset = REG_PAD_OWNER_BASE + ((raw_pin >> 3) << 2);
 	val = sys_read32(cfg->reg_base + offset);

 	/* get the bits about ownership */
 	offset = raw_pin % 8;
 	val = (val >> offset) & PAD_OWN_MASK;
 	if (val) {
 		/* PAD_OWN_HOST == 0, so !0 => false*/
 		return false;
 	}

 	/* Also need to make sure the function of pad is GPIO */
 	offset = data->pad_base + (raw_pin << 3);
 	val = sys_read32(cfg->reg_base + offset);
 	if (val & PAD_CFG0_PMODE_MASK) {
 		/* mode is not zero => not functioning as GPIO */
 		return false;
 	}

 	return true;
 }
 #else
 #define check_perm(...) (1)
 #endif

 /*
  * as the kernel initializes the subdevices, we add them
  * to the list of devices to check at ISR time.
  */

 static int nr_isr_devs;

 static struct device *isr_devs[GPIO_INTEL_APL_NR_SUBDEVS];

 static int gpio_intel_apl_isr(struct device *dev)
 {
 	const struct gpio_intel_apl_config *cfg;
 	struct gpio_intel_apl_data *data;
 	struct gpio_callback *cb, *tmp;
 	u32_t reg, int_sts, cur_mask, acc_mask;
 	int isr_dev;

 	for (isr_dev = 0; isr_dev < nr_isr_devs; ++isr_dev) {
 		dev = isr_devs[isr_dev];
 		cfg = dev->config->config_info;
 		data = dev->driver_data;

 		reg = cfg->reg_base + REG_GPI_INT_STS_BASE
 			+ ((cfg->pin_offset >> 5) << 2);
 		int_sts = sys_read32(reg);
 		acc_mask = 0U;

 		SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&data->cb, cb, tmp, node) {
 			cur_mask = int_sts & cb->pin_mask;
 			acc_mask |= cur_mask;
 			if (cur_mask) {
 				__ASSERT(cb->handler, "No callback handler!");
 				cb->handler(dev, cb, cur_mask);
 			}
 		}

 		/* clear handled interrupt bits */
 		sys_write32(acc_mask, reg);
 	}

 	return 0;
 }

 static int gpio_intel_apl_config(struct device *dev, int access_op,
 				 u32_t pin, int flags)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	struct gpio_intel_apl_data *data = dev->driver_data;
 	u32_t raw_pin, reg, cfg0, cfg1, val;

 	if (access_op != GPIO_ACCESS_BY_PIN) {
 		return -ENOTSUP;
 	}

 	/*
 	 * Pin must be input for interrupt to work.
 	 * And there is no double-edge trigger according
 	 * to datasheet.
 	 */
 	if ((flags & GPIO_INT)
 		&& ((flags & GPIO_DIR_OUT)
 			|| (flags & GPIO_INT_DOUBLE_EDGE))) {
 		return -EINVAL;
 	}

 	if ((flags & GPIO_POL_MASK) == GPIO_POL_INV) {
 		/* hardware cannot invert signal */
 		return -EINVAL;
 	}

 	if (pin > cfg->num_pins) {
 		return -EINVAL;
 	}
 	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

 	raw_pin = cfg->pin_offset + pin;

 	if (!check_perm(dev, raw_pin)) {
 		return -EPERM;
 	}

 	/* Set GPIO to trigger legacy interrupt */
 	if (flags & GPIO_INT) {
 		reg = cfg->reg_base + REG_PAD_HOST_SW_OWNER;
 		sys_bitfield_set_bit(reg, raw_pin);
 	}

 	/* read in pad configuration register */
 	reg = cfg->reg_base + data->pad_base + (raw_pin * 8U);
 	cfg0 = sys_read32(reg);
 	cfg1 = sys_read32(reg + 4);

 	/* change direction */
 	if ((flags & GPIO_DIR_MASK) == GPIO_DIR_OUT) {
 		/* pin to output */
 		cfg0 &= ~PAD_CFG0_TXDIS;
 		cfg0 |= PAD_CFG0_RXDIS;
 	} else {
 		/* pin to input */
 		cfg0 &= ~PAD_CFG0_RXDIS;
 		cfg0 |= PAD_CFG0_TXDIS;

 		/* don't override RX to 1 */
 		cfg0 &= ~PAD_CFG0_RXRAW1;
 	}

 	/* clear some bits first before interrupt setup */
 	cfg0 &= ~(PAD_CFG0_RXPADSTSEL | PAD_CFG0_RXINV
 		  | PAD_CFG0_RXEVCFG_MASK);

 	/* setup interrupt if desired */
 	if (flags & GPIO_INT) {
 		/* invert signal for interrupt controller */
 		if ((flags & GPIO_INT_ACTIVE_HIGH) == 0) {
 			cfg0 |= PAD_CFG0_RXINV;
 		}

 		/* level == 0 / edge == 1*/
 		if (flags & GPIO_INT_EDGE) {
 			cfg0 |= PAD_CFG0_RXEVCFG_EDGE;
 		}
 	} else {
 		/* set RX conf to drive 0 */
 		cfg0 |= PAD_CFG0_RXEVCFG_DRIVE0;
 	}

 	/* pull-up or pull-down */
 	val = flags & GPIO_PUD_MASK;
 	cfg1 &= ~PAD_CFG1_TERM_MASK;
 	if (val == GPIO_PUD_PULL_UP) {
 		cfg1 |= PAD_CFG1_TERM_PU;
 	} else if (val == GPIO_PUD_PULL_DOWN) {
 		cfg1 |= PAD_CFG1_TERM_PD;
 	} else {
 		cfg1 |= PAD_CFG1_TERM_NONE;
 	}

 	/* set IO Standby Termination to function mode */
 	cfg1 &= ~PAD_CFG1_IOSTERM_MASK;

 	/* IO Standby state to TX,RX enabled */
 	cfg1 &= ~PAD_CFG1_IOSSTATE_MASK;

 	/* write back pad configuration register after all changes */
 	sys_write32(cfg0, reg);
 	sys_write32(cfg1, (reg + 4));

 	return 0;
 }

 static int gpio_intel_apl_write(struct device *dev, int access_op,
 				u32_t pin, u32_t value)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	struct gpio_intel_apl_data *data = dev->driver_data;
 	u32_t raw_pin, reg, val;

 	if (access_op != GPIO_ACCESS_BY_PIN) {
 		return -ENOTSUP;
 	}

 	if (pin > cfg->num_pins) {
 		return -EINVAL;
 	}
 	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

 	raw_pin = cfg->pin_offset + pin;

 	if (!check_perm(dev, raw_pin)) {
 		return -EPERM;
 	}

 	reg = cfg->reg_base + data->pad_base + (raw_pin * 8U);
 	val = sys_read32(reg);

 	if (value) {
 		val |= PAD_CFG0_TXSTATE;
 	} else {
 		val &= ~PAD_CFG0_TXSTATE;
 	}

 	sys_write32(val, reg);

 	return 0;
 }

 static int gpio_intel_apl_read(struct device *dev, int access_op,
 			       u32_t pin, u32_t *value)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	struct gpio_intel_apl_data *data = dev->driver_data;
 	u32_t raw_pin, reg, val;

 	if (access_op != GPIO_ACCESS_BY_PIN) {
 		return -ENOTSUP;
 	}

 	if (pin > cfg->num_pins) {
 		return -EINVAL;
 	}
 	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

 	raw_pin = cfg->pin_offset + pin;

 	if (!check_perm(dev, raw_pin)) {
 		return -EPERM;
 	}

 	reg = cfg->reg_base + data->pad_base + (raw_pin * 8U);
 	val = sys_read32(reg);

 	if (!(val & PAD_CFG0_TXDIS)) {
 		/* If TX is not disabled, return TX_STATE */
 		*value = (val & PAD_CFG0_TXSTATE) >> PAD_CFG0_TXSTATE_POS;
 	} else {
 		/* else just return RX_STATE */
 		*value = (val & PAD_CFG0_RXSTATE) >> PAD_CFG0_RXSTATE_POS;
 	}

 	return 0;
 }

 static int gpio_intel_apl_manage_callback(struct device *dev,
 					  struct gpio_callback *callback,
 					  bool set)
 {
 	struct gpio_intel_apl_data *data = dev->driver_data;

 	return gpio_manage_callback(&data->cb, callback, set);
 }

 static int gpio_intel_apl_enable_callback(struct device *dev,
 					  int access_op, u32_t pin)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	u32_t raw_pin, reg;

 	if (access_op != GPIO_ACCESS_BY_PIN) {
 		return -ENOTSUP;
 	}

 	if (pin > cfg->num_pins) {
 		return -EINVAL;
 	}
 	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

 	raw_pin = cfg->pin_offset + pin;

 	if (!check_perm(dev, raw_pin)) {
 		return -EPERM;
 	}

 	/* clear (by setting) interrupt status bit */
 	reg = cfg->reg_base + REG_GPI_INT_STS_BASE;
 	sys_bitfield_set_bit(reg, raw_pin);

 	/* enable interrupt bit */
 	reg = cfg->reg_base + REG_GPI_INT_EN_BASE;
 	sys_bitfield_set_bit(reg, raw_pin);

 	return 0;
 }

 static int gpio_intel_apl_disable_callback(struct device *dev,
 					   int access_op, u32_t pin)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	u32_t raw_pin, reg;

 	if (access_op != GPIO_ACCESS_BY_PIN) {
 		return -ENOTSUP;
 	}

 	if (pin > cfg->num_pins) {
 		return -EINVAL;
 	}
 	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

 	raw_pin = cfg->pin_offset + pin;

 	if (!check_perm(dev, raw_pin)) {
 		return -EPERM;
 	}

 	/* disable interrupt bit */
 	reg = cfg->reg_base + REG_GPI_INT_EN_BASE;
 	sys_bitfield_clear_bit(reg, raw_pin);

 	return 0;
 }

 static const struct gpio_driver_api gpio_intel_apl_api = {
 	.config = gpio_intel_apl_config,
 	.write = gpio_intel_apl_write,
 	.read = gpio_intel_apl_read,
 	.manage_callback = gpio_intel_apl_manage_callback,
 	.enable_callback = gpio_intel_apl_enable_callback,
 	.disable_callback = gpio_intel_apl_disable_callback,
 };

 int gpio_intel_apl_init(struct device *dev)
 {
 	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
 	struct gpio_intel_apl_data *data = dev->driver_data;

 	data->pad_base = sys_read32(cfg->reg_base + REG_PAD_BASE_ADDR);

 	__ASSERT(nr_isr_devs < GPIO_INTEL_APL_NR_SUBDEVS, "too many subdevs");

 	if (nr_isr_devs == 0) {
 		IRQ_CONNECT(DT_APL_GPIO_IRQ,
 			    DT_APL_GPIO_IRQ_PRIORITY,
 			    gpio_intel_apl_isr, NULL,
 			    DT_APL_GPIO_IRQ_SENSE);

 		irq_enable(DT_APL_GPIO_IRQ);
 	}

 	isr_devs[nr_isr_devs++] = dev;

 	/* route to IRQ 14 */

 	sys_bitfield_clear_bit(data->pad_base + REG_MISCCFG,
 			       MISCCFG_IRQ_ROUTE_POS);

 	dev->driver_api = &gpio_intel_apl_api;

 	return 0;
 }

 #define GPIO_INTEL_APL_DEV_CFG_DATA(dir_l, dir_u, pos, offset, pins)	\
 static const struct gpio_intel_apl_config				\
 	gpio_intel_apl_cfg_##dir_l##_##pos = {				\
 	.reg_base = DT_APL_GPIO_BASE_ADDRESS_##dir_u,			\
 	.pin_offset = offset,						\
 	.num_pins = pins,						\
 };									\
 									\
 static struct gpio_intel_apl_data gpio_intel_apl_data_##dir_l##_##pos;	\
 									\
 DEVICE_AND_API_INIT(gpio_intel_apl_##dir_l##_##pos,			\
 		    DT_APL_GPIO_LABEL_##dir_u##_##pos,			\
 		    gpio_intel_apl_init,				\
 		    &gpio_intel_apl_data_##dir_l##_##pos,		\
 		    &gpio_intel_apl_cfg_##dir_l##_##pos,		\
 		    POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,	\
 		    &gpio_intel_apl_api)

 /* "sub" devices.  no more than GPIO_INTEL_APL_NR_SUBDEVS of these! */

 GPIO_INTEL_APL_DEV_CFG_DATA(n, N, 0, 0, 32);
 GPIO_INTEL_APL_DEV_CFG_DATA(n, N, 1, 32, 32);
 GPIO_INTEL_APL_DEV_CFG_DATA(n, N, 2, 32, 14);

 GPIO_INTEL_APL_DEV_CFG_DATA(nw, NW, 0, 0, 32);
 GPIO_INTEL_APL_DEV_CFG_DATA(nw, NW, 1, 32, 32);
 GPIO_INTEL_APL_DEV_CFG_DATA(nw, NW, 2, 32, 13);

 GPIO_INTEL_APL_DEV_CFG_DATA(w, W, 0, 0, 32);
 GPIO_INTEL_APL_DEV_CFG_DATA(w, W, 1, 32, 15);

 GPIO_INTEL_APL_DEV_CFG_DATA(sw, SW, 0, 0, 32);
 GPIO_INTEL_APL_DEV_CFG_DATA(sw, SW, 1, 32, 11);
	/*
	* Copyright (c) 2018-2019 Intel Corporation
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	/**
	* @file
	* @brief Intel Apollo Lake SoC GPIO Controller Driver
	*
	* The GPIO controller on Intel Apollo Lake SoC serves
	* both GPIOs and Pinmuxing function. This driver provides
	* the GPIO function.
	*
	* The GPIO controller has 245 pins divided into four sets.
	* Each set has its own MMIO address space. Due to GPIO
	* callback only allowing 32 pins (as a 32-bit mask) at once,
	* each set is further sub-divided into multiple devices, so
	* we export GPIO_INTEL_APL_NR_SUBDEVS devices to the kernel.
	*/

	#define GPIO_INTEL_APL_NR_SUBDEVS 10

	#include <errno.h>
	#include <drivers/gpio.h>
	#include <soc.h>
	#include <sys/sys_io.h>
	#include <sys/__assert.h>
	#include <sys/slist.h>
	#include <sys/speculation.h>

	#include "gpio_utils.h"

	/*
	* only IRQ 14 is supported now. the docs say IRQ 15 is supported
	* as well, but my (admitted cursory) testing disagrees.
	*/

	BUILD_ASSERT(DT_APL_GPIO_IRQ == 14);

	#define REG_PAD_BASE_ADDR 0x000C

	#define REG_MISCCFG 0x0010
	#define MISCCFG_IRQ_ROUTE_POS 3

	#define REG_PAD_OWNER_BASE 0x0020
	#define PAD_OWN_MASK 0x03
	#define PAD_OWN_HOST 0
	#define PAD_OWN_CSME 1
	#define PAD_OWN_ISH 2
	#define PAD_OWN_IE 3

	#define REG_PAD_HOST_SW_OWNER 0x0080
	#define PAD_HOST_SW_OWN_GPIO 1
	#define PAD_HOST_SW_OWN_ACPI 0

	#define REG_GPI_INT_STS_BASE 0x0100
	#define REG_GPI_INT_EN_BASE 0x0110

	#define PAD_CFG0_RXPADSTSEL BIT(29)
	#define PAD_CFG0_RXRAW1 BIT(28)

	#define PAD_CFG0_PMODE_MASK (0x0F << 10)

	#define PAD_CFG0_RXEVCFG_POS 25
	#define PAD_CFG0_RXEVCFG_MASK (0x03 << PAD_CFG0_RXEVCFG_POS)
	#define PAD_CFG0_RXEVCFG_LEVEL (0 << PAD_CFG0_RXEVCFG_POS)
	#define PAD_CFG0_RXEVCFG_EDGE (1 << PAD_CFG0_RXEVCFG_POS)
	#define PAD_CFG0_RXEVCFG_DRIVE0 (2 << PAD_CFG0_RXEVCFG_POS)

	#define PAD_CFG0_PREGFRXSEL BIT(24)
	#define PAD_CFG0_RXINV BIT(23)

	#define PAD_CFG0_RXDIS BIT(9)
	#define PAD_CFG0_TXDIS BIT(8)
	#define PAD_CFG0_RXSTATE BIT(1)
	#define PAD_CFG0_RXSTATE_POS 1
	#define PAD_CFG0_TXSTATE BIT(0)
	#define PAD_CFG0_TXSTATE_POS 0

	#define PAD_CFG1_IOSTERM_POS 8
	#define PAD_CFG1_IOSTERM_MASK (0x03 << PAD_CFG1_IOSTERM_POS)
	#define PAD_CFG1_IOSTERM_FUNC (0 << PAD_CFG1_IOSTERM_POS)
	#define PAD_CFG1_IOSTERM_DISPUD (1 << PAD_CFG1_IOSTERM_POS)
	#define PAD_CFG1_IOSTERM_PU (2 << PAD_CFG1_IOSTERM_POS)
	#define PAD_CFG1_IOSTERM_PD (3 << PAD_CFG1_IOSTERM_POS)

	#define PAD_CFG1_TERM_POS 10
	#define PAD_CFG1_TERM_MASK (0x0F << PAD_CFG1_TERM_POS)
	#define PAD_CFG1_TERM_NONE (0x00 << PAD_CFG1_TERM_POS)
	#define PAD_CFG1_TERM_PD (0x04 << PAD_CFG1_TERM_POS)
	#define PAD_CFG1_TERM_PU (0x0C << PAD_CFG1_TERM_POS)

	#define PAD_CFG1_IOSSTATE_POS 14
	#define PAD_CFG1_IOSSTATE_MASK (0x0F << PAD_CFG1_IOSSTATE_POS)
	#define PAD_CFG1_IOSSTATE_IGNORE (0x0F << PAD_CFG1_IOSSTATE_POS)

	struct gpio_intel_apl_config {
	u32_t reg_base;

	u8_t pin_offset;
	u8_t num_pins;
	};

	struct gpio_intel_apl_data {
	/* Pad base address */
	u32_t pad_base;

	sys_slist_t cb;
	};

	#ifdef CONFIG_GPIO_INTEL_APL_CHECK_PERMS
	/**
	* @brief Check if host has permission to alter this GPIO pin.
	*
	* @param "struct device *dev" Device struct
	* @param "u32_t raw_pin" Raw GPIO pin
	*
	* @return true if host owns the GPIO pin, false otherwise
	*/
	static bool check_perm(struct device *dev, u32_t raw_pin)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	struct gpio_intel_apl_data *data = dev->driver_data;
	u32_t offset, val;

	/* First is to establish that host software owns the pin */

	/* read the Pad Ownership register related to the pin */
	offset = REG_PAD_OWNER_BASE + ((raw_pin >> 3) << 2);
	val = sys_read32(cfg->reg_base + offset);

	/* get the bits about ownership */
	offset = raw_pin % 8;
	val = (val >> offset) & PAD_OWN_MASK;
	if (val) {
	/* PAD_OWN_HOST == 0, so !0 => false*/
	return false;
	}

	/* Also need to make sure the function of pad is GPIO */
	offset = data->pad_base + (raw_pin << 3);
	val = sys_read32(cfg->reg_base + offset);
	if (val & PAD_CFG0_PMODE_MASK) {
	/* mode is not zero => not functioning as GPIO */
	return false;
	}

	return true;
	}
	#else
	#define check_perm(...) (1)
	#endif

	/*
	* as the kernel initializes the subdevices, we add them
	* to the list of devices to check at ISR time.
	*/

	static int nr_isr_devs;

	static struct device *isr_devs[GPIO_INTEL_APL_NR_SUBDEVS];

	static int gpio_intel_apl_isr(struct device *dev)
	{
	const struct gpio_intel_apl_config *cfg;
	struct gpio_intel_apl_data *data;
	struct gpio_callback cb, tmp;
	u32_t reg, int_sts, cur_mask, acc_mask;
	int isr_dev;

	for (isr_dev = 0; isr_dev < nr_isr_devs; ++isr_dev) {
	dev = isr_devs[isr_dev];
	cfg = dev->config->config_info;
	data = dev->driver_data;

	reg = cfg->reg_base + REG_GPI_INT_STS_BASE
	+ ((cfg->pin_offset >> 5) << 2);
	int_sts = sys_read32(reg);
	acc_mask = 0U;

	SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&data->cb, cb, tmp, node) {
	cur_mask = int_sts & cb->pin_mask;
	acc_mask \|= cur_mask;
	if (cur_mask) {
	__ASSERT(cb->handler, "No callback handler!");
	cb->handler(dev, cb, cur_mask);
	}
	}

	/* clear handled interrupt bits */
	sys_write32(acc_mask, reg);
	}

	return 0;
	}

	static int gpio_intel_apl_config(struct device *dev, int access_op,
	u32_t pin, int flags)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	struct gpio_intel_apl_data *data = dev->driver_data;
	u32_t raw_pin, reg, cfg0, cfg1, val;

	if (access_op != GPIO_ACCESS_BY_PIN) {
	return -ENOTSUP;
	}

	/*
	* Pin must be input for interrupt to work.
	* And there is no double-edge trigger according
	* to datasheet.
	*/
	if ((flags & GPIO_INT)
	&& ((flags & GPIO_DIR_OUT)
	\|\| (flags & GPIO_INT_DOUBLE_EDGE))) {
	return -EINVAL;
	}

	if ((flags & GPIO_POL_MASK) == GPIO_POL_INV) {
	/* hardware cannot invert signal */
	return -EINVAL;
	}

	if (pin > cfg->num_pins) {
	return -EINVAL;
	}
	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

	raw_pin = cfg->pin_offset + pin;

	if (!check_perm(dev, raw_pin)) {
	return -EPERM;
	}

	/* Set GPIO to trigger legacy interrupt */
	if (flags & GPIO_INT) {
	reg = cfg->reg_base + REG_PAD_HOST_SW_OWNER;
	sys_bitfield_set_bit(reg, raw_pin);
	}

	/* read in pad configuration register */
	reg = cfg->reg_base + data->pad_base + (raw_pin * 8U);
	cfg0 = sys_read32(reg);
	cfg1 = sys_read32(reg + 4);

	/* change direction */
	if ((flags & GPIO_DIR_MASK) == GPIO_DIR_OUT) {
	/* pin to output */
	cfg0 &= ~PAD_CFG0_TXDIS;
	cfg0 \|= PAD_CFG0_RXDIS;
	} else {
	/* pin to input */
	cfg0 &= ~PAD_CFG0_RXDIS;
	cfg0 \|= PAD_CFG0_TXDIS;

	/* don't override RX to 1 */
	cfg0 &= ~PAD_CFG0_RXRAW1;
	}

	/* clear some bits first before interrupt setup */
	cfg0 &= ~(PAD_CFG0_RXPADSTSEL \| PAD_CFG0_RXINV
	\| PAD_CFG0_RXEVCFG_MASK);

	/* setup interrupt if desired */
	if (flags & GPIO_INT) {
	/* invert signal for interrupt controller */
	if ((flags & GPIO_INT_ACTIVE_HIGH) == 0) {
	cfg0 \|= PAD_CFG0_RXINV;
	}

	/* level == 0 / edge == 1*/
	if (flags & GPIO_INT_EDGE) {
	cfg0 \|= PAD_CFG0_RXEVCFG_EDGE;
	}
	} else {
	/* set RX conf to drive 0 */
	cfg0 \|= PAD_CFG0_RXEVCFG_DRIVE0;
	}

	/* pull-up or pull-down */
	val = flags & GPIO_PUD_MASK;
	cfg1 &= ~PAD_CFG1_TERM_MASK;
	if (val == GPIO_PUD_PULL_UP) {
	cfg1 \|= PAD_CFG1_TERM_PU;
	} else if (val == GPIO_PUD_PULL_DOWN) {
	cfg1 \|= PAD_CFG1_TERM_PD;
	} else {
	cfg1 \|= PAD_CFG1_TERM_NONE;
	}

	/* set IO Standby Termination to function mode */
	cfg1 &= ~PAD_CFG1_IOSTERM_MASK;

	/* IO Standby state to TX,RX enabled */
	cfg1 &= ~PAD_CFG1_IOSSTATE_MASK;

	/* write back pad configuration register after all changes */
	sys_write32(cfg0, reg);
	sys_write32(cfg1, (reg + 4));

	return 0;
	}

	static int gpio_intel_apl_write(struct device *dev, int access_op,
	u32_t pin, u32_t value)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	struct gpio_intel_apl_data *data = dev->driver_data;
	u32_t raw_pin, reg, val;

	if (access_op != GPIO_ACCESS_BY_PIN) {
	return -ENOTSUP;
	}

	if (pin > cfg->num_pins) {
	return -EINVAL;
	}
	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

	raw_pin = cfg->pin_offset + pin;

	if (!check_perm(dev, raw_pin)) {
	return -EPERM;
	}

	reg = cfg->reg_base + data->pad_base + (raw_pin * 8U);
	val = sys_read32(reg);

	if (value) {
	val \|= PAD_CFG0_TXSTATE;
	} else {
	val &= ~PAD_CFG0_TXSTATE;
	}

	sys_write32(val, reg);

	return 0;
	}

	static int gpio_intel_apl_read(struct device *dev, int access_op,
	u32_t pin, u32_t *value)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	struct gpio_intel_apl_data *data = dev->driver_data;
	u32_t raw_pin, reg, val;

	if (access_op != GPIO_ACCESS_BY_PIN) {
	return -ENOTSUP;
	}

	if (pin > cfg->num_pins) {
	return -EINVAL;
	}
	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

	raw_pin = cfg->pin_offset + pin;

	if (!check_perm(dev, raw_pin)) {
	return -EPERM;
	}

	reg = cfg->reg_base + data->pad_base + (raw_pin * 8U);
	val = sys_read32(reg);

	if (!(val & PAD_CFG0_TXDIS)) {
	/* If TX is not disabled, return TX_STATE */
	*value = (val & PAD_CFG0_TXSTATE) >> PAD_CFG0_TXSTATE_POS;
	} else {
	/* else just return RX_STATE */
	*value = (val & PAD_CFG0_RXSTATE) >> PAD_CFG0_RXSTATE_POS;
	}

	return 0;
	}

	static int gpio_intel_apl_manage_callback(struct device *dev,
	struct gpio_callback *callback,
	bool set)
	{
	struct gpio_intel_apl_data *data = dev->driver_data;

	return gpio_manage_callback(&data->cb, callback, set);
	}

	static int gpio_intel_apl_enable_callback(struct device *dev,
	int access_op, u32_t pin)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	u32_t raw_pin, reg;

	if (access_op != GPIO_ACCESS_BY_PIN) {
	return -ENOTSUP;
	}

	if (pin > cfg->num_pins) {
	return -EINVAL;
	}
	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

	raw_pin = cfg->pin_offset + pin;

	if (!check_perm(dev, raw_pin)) {
	return -EPERM;
	}

	/* clear (by setting) interrupt status bit */
	reg = cfg->reg_base + REG_GPI_INT_STS_BASE;
	sys_bitfield_set_bit(reg, raw_pin);

	/* enable interrupt bit */
	reg = cfg->reg_base + REG_GPI_INT_EN_BASE;
	sys_bitfield_set_bit(reg, raw_pin);

	return 0;
	}

	static int gpio_intel_apl_disable_callback(struct device *dev,
	int access_op, u32_t pin)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	u32_t raw_pin, reg;

	if (access_op != GPIO_ACCESS_BY_PIN) {
	return -ENOTSUP;
	}

	if (pin > cfg->num_pins) {
	return -EINVAL;
	}
	pin = k_array_index_sanitize(pin, cfg->num_pins + 1);

	raw_pin = cfg->pin_offset + pin;

	if (!check_perm(dev, raw_pin)) {
	return -EPERM;
	}

	/* disable interrupt bit */
	reg = cfg->reg_base + REG_GPI_INT_EN_BASE;
	sys_bitfield_clear_bit(reg, raw_pin);

	return 0;
	}

	static const struct gpio_driver_api gpio_intel_apl_api = {
	.config = gpio_intel_apl_config,
	.write = gpio_intel_apl_write,
	.read = gpio_intel_apl_read,
	.manage_callback = gpio_intel_apl_manage_callback,
	.enable_callback = gpio_intel_apl_enable_callback,
	.disable_callback = gpio_intel_apl_disable_callback,
	};

	int gpio_intel_apl_init(struct device *dev)
	{
	const struct gpio_intel_apl_config *cfg = dev->config->config_info;
	struct gpio_intel_apl_data *data = dev->driver_data;

	data->pad_base = sys_read32(cfg->reg_base + REG_PAD_BASE_ADDR);

	__ASSERT(nr_isr_devs < GPIO_INTEL_APL_NR_SUBDEVS, "too many subdevs");

	if (nr_isr_devs == 0) {
	IRQ_CONNECT(DT_APL_GPIO_IRQ,
	DT_APL_GPIO_IRQ_PRIORITY,
	gpio_intel_apl_isr, NULL,
	DT_APL_GPIO_IRQ_SENSE);

	irq_enable(DT_APL_GPIO_IRQ);
	}

	isr_devs[nr_isr_devs++] = dev;

	/* route to IRQ 14 */

	sys_bitfield_clear_bit(data->pad_base + REG_MISCCFG,
	MISCCFG_IRQ_ROUTE_POS);

	dev->driver_api = &gpio_intel_apl_api;

	return 0;
	}

	#define GPIO_INTEL_APL_DEV_CFG_DATA(dir_l, dir_u, pos, offset, pins) \
	static const struct gpio_intel_apl_config \
	gpio_intel_apl_cfg_##dir_l##_##pos = { \
	.reg_base = DT_APL_GPIO_BASE_ADDRESS_##dir_u, \
	.pin_offset = offset, \
	.num_pins = pins, \
	}; \
	\
	static struct gpio_intel_apl_data gpio_intel_apl_data_##dir_l##_##pos; \
	\
	DEVICE_AND_API_INIT(gpio_intel_apl_##dir_l##_##pos, \
	DT_APL_GPIO_LABEL_##dir_u##_##pos, \
	gpio_intel_apl_init, \
	&gpio_intel_apl_data_##dir_l##_##pos, \
	&gpio_intel_apl_cfg_##dir_l##_##pos, \
	POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \
	&gpio_intel_apl_api)

	/* "sub" devices. no more than GPIO_INTEL_APL_NR_SUBDEVS of these! */

	GPIO_INTEL_APL_DEV_CFG_DATA(n, N, 0, 0, 32);
	GPIO_INTEL_APL_DEV_CFG_DATA(n, N, 1, 32, 32);
	GPIO_INTEL_APL_DEV_CFG_DATA(n, N, 2, 32, 14);

	GPIO_INTEL_APL_DEV_CFG_DATA(nw, NW, 0, 0, 32);
	GPIO_INTEL_APL_DEV_CFG_DATA(nw, NW, 1, 32, 32);
	GPIO_INTEL_APL_DEV_CFG_DATA(nw, NW, 2, 32, 13);

	GPIO_INTEL_APL_DEV_CFG_DATA(w, W, 0, 0, 32);
	GPIO_INTEL_APL_DEV_CFG_DATA(w, W, 1, 32, 15);

	GPIO_INTEL_APL_DEV_CFG_DATA(sw, SW, 0, 0, 32);
	GPIO_INTEL_APL_DEV_CFG_DATA(sw, SW, 1, 32, 11);