drivers/gpio/gpio-aspeed-sgpio.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright 2019 American Megatrends International LLC.
  *
  * Author: Karthikeyan Mani <karthikeyanm@amiindia.co.in>
  */

 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/gpio/driver.h>
 #include <linux/hashtable.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>

 #define MAX_NR_SGPIO			80

 #define ASPEED_SGPIO_CTRL		0x54

 #define ASPEED_SGPIO_PINS_MASK		GENMASK(9, 6)
 #define ASPEED_SGPIO_CLK_DIV_MASK	GENMASK(31, 16)
 #define ASPEED_SGPIO_ENABLE		BIT(0)

 struct aspeed_sgpio {
 	struct gpio_chip chip;
 	struct clk *pclk;
 	spinlock_t lock;
 	void __iomem *base;
 	uint32_t dir_in[3];
 	int irq;
 };

 struct aspeed_sgpio_bank {
 	uint16_t    val_regs;
 	uint16_t    rdata_reg;
 	uint16_t    irq_regs;
 	const char  names[4][3];
 };

 /*
  * Note: The "value" register returns the input value when the GPIO is
  *	 configured as an input.
  *
  *	 The "rdata" register returns the output value when the GPIO is
  *	 configured as an output.
  */
 static const struct aspeed_sgpio_bank aspeed_sgpio_banks[] = {
 	{
 		.val_regs = 0x0000,
 		.rdata_reg = 0x0070,
 		.irq_regs = 0x0004,
 		.names = { "A", "B", "C", "D" },
 	},
 	{
 		.val_regs = 0x001C,
 		.rdata_reg = 0x0074,
 		.irq_regs = 0x0020,
 		.names = { "E", "F", "G", "H" },
 	},
 	{
 		.val_regs = 0x0038,
 		.rdata_reg = 0x0078,
 		.irq_regs = 0x003C,
 		.names = { "I", "J" },
 	},
 };

 enum aspeed_sgpio_reg {
 	reg_val,
 	reg_rdata,
 	reg_irq_enable,
 	reg_irq_type0,
 	reg_irq_type1,
 	reg_irq_type2,
 	reg_irq_status,
 };

 #define GPIO_VAL_VALUE      0x00
 #define GPIO_IRQ_ENABLE     0x00
 #define GPIO_IRQ_TYPE0      0x04
 #define GPIO_IRQ_TYPE1      0x08
 #define GPIO_IRQ_TYPE2      0x0C
 #define GPIO_IRQ_STATUS     0x10

 static void __iomem *bank_reg(struct aspeed_sgpio *gpio,
 				     const struct aspeed_sgpio_bank *bank,
 				     const enum aspeed_sgpio_reg reg)
 {
 	switch (reg) {
 	case reg_val:
 		return gpio->base + bank->val_regs + GPIO_VAL_VALUE;
 	case reg_rdata:
 		return gpio->base + bank->rdata_reg;
 	case reg_irq_enable:
 		return gpio->base + bank->irq_regs + GPIO_IRQ_ENABLE;
 	case reg_irq_type0:
 		return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE0;
 	case reg_irq_type1:
 		return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE1;
 	case reg_irq_type2:
 		return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE2;
 	case reg_irq_status:
 		return gpio->base + bank->irq_regs + GPIO_IRQ_STATUS;
 	default:
 		/* acturally if code runs to here, it's an error case */
 		BUG();
 	}
 }

 #define GPIO_BANK(x)    ((x) >> 5)
 #define GPIO_OFFSET(x)  ((x) & 0x1f)
 #define GPIO_BIT(x)     BIT(GPIO_OFFSET(x))

 static const struct aspeed_sgpio_bank *to_bank(unsigned int offset)
 {
 	unsigned int bank = GPIO_BANK(offset);

 	WARN_ON(bank >= ARRAY_SIZE(aspeed_sgpio_banks));
 	return &aspeed_sgpio_banks[bank];
 }

 static int aspeed_sgpio_get(struct gpio_chip *gc, unsigned int offset)
 {
 	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
 	const struct aspeed_sgpio_bank *bank = to_bank(offset);
 	unsigned long flags;
 	enum aspeed_sgpio_reg reg;
 	bool is_input;
 	int rc = 0;

 	spin_lock_irqsave(&gpio->lock, flags);

 	is_input = gpio->dir_in[GPIO_BANK(offset)] & GPIO_BIT(offset);
 	reg = is_input ? reg_val : reg_rdata;
 	rc = !!(ioread32(bank_reg(gpio, bank, reg)) & GPIO_BIT(offset));

 	spin_unlock_irqrestore(&gpio->lock, flags);

 	return rc;
 }

 static void sgpio_set_value(struct gpio_chip *gc, unsigned int offset, int val)
 {
 	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
 	const struct aspeed_sgpio_bank *bank = to_bank(offset);
 	void __iomem *addr;
 	u32 reg = 0;

 	addr = bank_reg(gpio, bank, reg_val);
 	reg = ioread32(addr);

 	if (val)
 		reg |= GPIO_BIT(offset);
 	else
 		reg &= ~GPIO_BIT(offset);

 	iowrite32(reg, addr);
 }

 static void aspeed_sgpio_set(struct gpio_chip *gc, unsigned int offset, int val)
 {
 	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
 	unsigned long flags;

 	spin_lock_irqsave(&gpio->lock, flags);

 	sgpio_set_value(gc, offset, val);

 	spin_unlock_irqrestore(&gpio->lock, flags);
 }

 static int aspeed_sgpio_dir_in(struct gpio_chip *gc, unsigned int offset)
 {
 	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
 	unsigned long flags;

 	spin_lock_irqsave(&gpio->lock, flags);
 	gpio->dir_in[GPIO_BANK(offset)] |= GPIO_BIT(offset);
 	spin_unlock_irqrestore(&gpio->lock, flags);

 	return 0;
 }

 static int aspeed_sgpio_dir_out(struct gpio_chip *gc, unsigned int offset, int val)
 {
 	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
 	unsigned long flags;

 	spin_lock_irqsave(&gpio->lock, flags);

 	gpio->dir_in[GPIO_BANK(offset)] &= ~GPIO_BIT(offset);
 	sgpio_set_value(gc, offset, val);

 	spin_unlock_irqrestore(&gpio->lock, flags);

 	return 0;
 }

 static int aspeed_sgpio_get_direction(struct gpio_chip *gc, unsigned int offset)
 {
 	int dir_status;
 	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
 	unsigned long flags;

 	spin_lock_irqsave(&gpio->lock, flags);
 	dir_status = gpio->dir_in[GPIO_BANK(offset)] & GPIO_BIT(offset);
 	spin_unlock_irqrestore(&gpio->lock, flags);

 	return dir_status;

 }

 static void irqd_to_aspeed_sgpio_data(struct irq_data *d,
 					struct aspeed_sgpio **gpio,
 					const struct aspeed_sgpio_bank **bank,
 					u32 *bit, int *offset)
 {
 	struct aspeed_sgpio *internal;

 	*offset = irqd_to_hwirq(d);
 	internal = irq_data_get_irq_chip_data(d);
 	WARN_ON(!internal);

 	*gpio = internal;
 	*bank = to_bank(*offset);
 	*bit = GPIO_BIT(*offset);
 }

 static void aspeed_sgpio_irq_ack(struct irq_data *d)
 {
 	const struct aspeed_sgpio_bank *bank;
 	struct aspeed_sgpio *gpio;
 	unsigned long flags;
 	void __iomem *status_addr;
 	int offset;
 	u32 bit;

 	irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);

 	status_addr = bank_reg(gpio, bank, reg_irq_status);

 	spin_lock_irqsave(&gpio->lock, flags);

 	iowrite32(bit, status_addr);

 	spin_unlock_irqrestore(&gpio->lock, flags);
 }

 static void aspeed_sgpio_irq_set_mask(struct irq_data *d, bool set)
 {
 	const struct aspeed_sgpio_bank *bank;
 	struct aspeed_sgpio *gpio;
 	unsigned long flags;
 	u32 reg, bit;
 	void __iomem *addr;
 	int offset;

 	irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
 	addr = bank_reg(gpio, bank, reg_irq_enable);

 	spin_lock_irqsave(&gpio->lock, flags);

 	reg = ioread32(addr);
 	if (set)
 		reg |= bit;
 	else
 		reg &= ~bit;

 	iowrite32(reg, addr);

 	spin_unlock_irqrestore(&gpio->lock, flags);
 }

 static void aspeed_sgpio_irq_mask(struct irq_data *d)
 {
 	aspeed_sgpio_irq_set_mask(d, false);
 }

 static void aspeed_sgpio_irq_unmask(struct irq_data *d)
 {
 	aspeed_sgpio_irq_set_mask(d, true);
 }

 static int aspeed_sgpio_set_type(struct irq_data *d, unsigned int type)
 {
 	u32 type0 = 0;
 	u32 type1 = 0;
 	u32 type2 = 0;
 	u32 bit, reg;
 	const struct aspeed_sgpio_bank *bank;
 	irq_flow_handler_t handler;
 	struct aspeed_sgpio *gpio;
 	unsigned long flags;
 	void __iomem *addr;
 	int offset;

 	irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);

 	switch (type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_EDGE_BOTH:
 		type2 |= bit;
 		/* fall through */
 	case IRQ_TYPE_EDGE_RISING:
 		type0 |= bit;
 		/* fall through */
 	case IRQ_TYPE_EDGE_FALLING:
 		handler = handle_edge_irq;
 		break;
 	case IRQ_TYPE_LEVEL_HIGH:
 		type0 |= bit;
 		/* fall through */
 	case IRQ_TYPE_LEVEL_LOW:
 		type1 |= bit;
 		handler = handle_level_irq;
 		break;
 	default:
 		return -EINVAL;
 	}

 	spin_lock_irqsave(&gpio->lock, flags);

 	addr = bank_reg(gpio, bank, reg_irq_type0);
 	reg = ioread32(addr);
 	reg = (reg & ~bit) | type0;
 	iowrite32(reg, addr);

 	addr = bank_reg(gpio, bank, reg_irq_type1);
 	reg = ioread32(addr);
 	reg = (reg & ~bit) | type1;
 	iowrite32(reg, addr);

 	addr = bank_reg(gpio, bank, reg_irq_type2);
 	reg = ioread32(addr);
 	reg = (reg & ~bit) | type2;
 	iowrite32(reg, addr);

 	spin_unlock_irqrestore(&gpio->lock, flags);

 	irq_set_handler_locked(d, handler);

 	return 0;
 }

 static void aspeed_sgpio_irq_handler(struct irq_desc *desc)
 {
 	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
 	struct irq_chip *ic = irq_desc_get_chip(desc);
 	struct aspeed_sgpio *data = gpiochip_get_data(gc);
 	unsigned int i, p, girq;
 	unsigned long reg;

 	chained_irq_enter(ic, desc);

 	for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
 		const struct aspeed_sgpio_bank *bank = &aspeed_sgpio_banks[i];

 		reg = ioread32(bank_reg(data, bank, reg_irq_status));

 		for_each_set_bit(p, &reg, 32) {
 			girq = irq_find_mapping(gc->irq.domain, i * 32 + p);
 			generic_handle_irq(girq);
 		}

 	}

 	chained_irq_exit(ic, desc);
 }

 static struct irq_chip aspeed_sgpio_irqchip = {
 	.name       = "aspeed-sgpio",
 	.irq_ack    = aspeed_sgpio_irq_ack,
 	.irq_mask   = aspeed_sgpio_irq_mask,
 	.irq_unmask = aspeed_sgpio_irq_unmask,
 	.irq_set_type   = aspeed_sgpio_set_type,
 };

 static int aspeed_sgpio_setup_irqs(struct aspeed_sgpio *gpio,
 				   struct platform_device *pdev)
 {
 	int rc, i;
 	const struct aspeed_sgpio_bank *bank;
 	struct gpio_irq_chip *irq;

 	rc = platform_get_irq(pdev, 0);
 	if (rc < 0)
 		return rc;

 	gpio->irq = rc;

 	/* Disable IRQ and clear Interrupt status registers for all SGPIO Pins. */
 	for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
 		bank =  &aspeed_sgpio_banks[i];
 		/* disable irq enable bits */
 		iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_enable));
 		/* clear status bits */
 		iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_status));
 	}

 	irq = &gpio->chip.irq;
 	irq->chip = &aspeed_sgpio_irqchip;
 	irq->handler = handle_bad_irq;
 	irq->default_type = IRQ_TYPE_NONE;
 	irq->parent_handler = aspeed_sgpio_irq_handler;
 	irq->parent_handler_data = gpio;
 	irq->parents = &gpio->irq;
 	irq->num_parents = 1;

 	/* set IRQ settings and Enable Interrupt */
 	for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
 		bank = &aspeed_sgpio_banks[i];
 		/* set falling or level-low irq */
 		iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_type0));
 		/* trigger type is edge */
 		iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_type1));
 		/* dual edge trigger mode. */
 		iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_type2));
 		/* enable irq */
 		iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_enable));
 	}

 	return 0;
 }

 static const struct of_device_id aspeed_sgpio_of_table[] = {
 	{ .compatible = "aspeed,ast2400-sgpio" },
 	{ .compatible = "aspeed,ast2500-sgpio" },
 	{}
 };

 MODULE_DEVICE_TABLE(of, aspeed_sgpio_of_table);

 static int __init aspeed_sgpio_probe(struct platform_device *pdev)
 {
 	struct aspeed_sgpio *gpio;
 	u32 nr_gpios, sgpio_freq, sgpio_clk_div;
 	int rc;
 	unsigned long apb_freq;

 	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
 	if (!gpio)
 		return -ENOMEM;

 	gpio->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(gpio->base))
 		return PTR_ERR(gpio->base);

 	rc = of_property_read_u32(pdev->dev.of_node, "ngpios", &nr_gpios);
 	if (rc < 0) {
 		dev_err(&pdev->dev, "Could not read ngpios property\n");
 		return -EINVAL;
 	} else if (nr_gpios > MAX_NR_SGPIO) {
 		dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d: %d\n",
 			MAX_NR_SGPIO, nr_gpios);
 		return -EINVAL;
 	}

 	rc = of_property_read_u32(pdev->dev.of_node, "bus-frequency", &sgpio_freq);
 	if (rc < 0) {
 		dev_err(&pdev->dev, "Could not read bus-frequency property\n");
 		return -EINVAL;
 	}

 	gpio->pclk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(gpio->pclk)) {
 		dev_err(&pdev->dev, "devm_clk_get failed\n");
 		return PTR_ERR(gpio->pclk);
 	}

 	apb_freq = clk_get_rate(gpio->pclk);

 	/*
 	 * From the datasheet,
 	 *	SGPIO period = 1/PCLK * 2 * (GPIO254[31:16] + 1)
 	 *	period = 2 * (GPIO254[31:16] + 1) / PCLK
 	 *	frequency = 1 / (2 * (GPIO254[31:16] + 1) / PCLK)
 	 *	frequency = PCLK / (2 * (GPIO254[31:16] + 1))
 	 *	frequency * 2 * (GPIO254[31:16] + 1) = PCLK
 	 *	GPIO254[31:16] = PCLK / (frequency * 2) - 1
 	 */
 	if (sgpio_freq == 0)
 		return -EINVAL;

 	sgpio_clk_div = (apb_freq / (sgpio_freq * 2)) - 1;

 	if (sgpio_clk_div > (1 << 16) - 1)
 		return -EINVAL;

 	iowrite32(FIELD_PREP(ASPEED_SGPIO_CLK_DIV_MASK, sgpio_clk_div) |
 		  FIELD_PREP(ASPEED_SGPIO_PINS_MASK, (nr_gpios / 8)) |
 		  ASPEED_SGPIO_ENABLE,
 		  gpio->base + ASPEED_SGPIO_CTRL);

 	spin_lock_init(&gpio->lock);

 	gpio->chip.parent = &pdev->dev;
 	gpio->chip.ngpio = nr_gpios;
 	gpio->chip.direction_input = aspeed_sgpio_dir_in;
 	gpio->chip.direction_output = aspeed_sgpio_dir_out;
 	gpio->chip.get_direction = aspeed_sgpio_get_direction;
 	gpio->chip.request = NULL;
 	gpio->chip.free = NULL;
 	gpio->chip.get = aspeed_sgpio_get;
 	gpio->chip.set = aspeed_sgpio_set;
 	gpio->chip.set_config = NULL;
 	gpio->chip.label = dev_name(&pdev->dev);
 	gpio->chip.base = -1;

 	/* set all SGPIO pins as input (1). */
 	memset(gpio->dir_in, 0xff, sizeof(gpio->dir_in));

 	aspeed_sgpio_setup_irqs(gpio, pdev);

 	rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
 	if (rc < 0)
 		return rc;

 	return 0;
 }

 static struct platform_driver aspeed_sgpio_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
 		.of_match_table = aspeed_sgpio_of_table,
 	},
 };

 module_platform_driver_probe(aspeed_sgpio_driver, aspeed_sgpio_probe);
 MODULE_DESCRIPTION("Aspeed Serial GPIO Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright 2019 American Megatrends International LLC.
	*
	* Author: Karthikeyan Mani <karthikeyanm@amiindia.co.in>
	*/

	#include <linux/bitfield.h>
	#include <linux/clk.h>
	#include <linux/gpio/driver.h>
	#include <linux/hashtable.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/spinlock.h>
	#include <linux/string.h>

	#define MAX_NR_SGPIO 80

	#define ASPEED_SGPIO_CTRL 0x54

	#define ASPEED_SGPIO_PINS_MASK GENMASK(9, 6)
	#define ASPEED_SGPIO_CLK_DIV_MASK GENMASK(31, 16)
	#define ASPEED_SGPIO_ENABLE BIT(0)

	struct aspeed_sgpio {
	struct gpio_chip chip;
	struct clk *pclk;
	spinlock_t lock;
	void __iomem *base;
	uint32_t dir_in[3];
	int irq;
	};

	struct aspeed_sgpio_bank {
	uint16_t val_regs;
	uint16_t rdata_reg;
	uint16_t irq_regs;
	const char names[4][3];
	};

	/*
	* Note: The "value" register returns the input value when the GPIO is
	* configured as an input.
	*
	* The "rdata" register returns the output value when the GPIO is
	* configured as an output.
	*/
	static const struct aspeed_sgpio_bank aspeed_sgpio_banks[] = {
	{
	.val_regs = 0x0000,
	.rdata_reg = 0x0070,
	.irq_regs = 0x0004,
	.names = { "A", "B", "C", "D" },
	},
	{
	.val_regs = 0x001C,
	.rdata_reg = 0x0074,
	.irq_regs = 0x0020,
	.names = { "E", "F", "G", "H" },
	},
	{
	.val_regs = 0x0038,
	.rdata_reg = 0x0078,
	.irq_regs = 0x003C,
	.names = { "I", "J" },
	},
	};

	enum aspeed_sgpio_reg {
	reg_val,
	reg_rdata,
	reg_irq_enable,
	reg_irq_type0,
	reg_irq_type1,
	reg_irq_type2,
	reg_irq_status,
	};

	#define GPIO_VAL_VALUE 0x00
	#define GPIO_IRQ_ENABLE 0x00
	#define GPIO_IRQ_TYPE0 0x04
	#define GPIO_IRQ_TYPE1 0x08
	#define GPIO_IRQ_TYPE2 0x0C
	#define GPIO_IRQ_STATUS 0x10

	static void __iomem bank_reg(struct aspeed_sgpio gpio,
	const struct aspeed_sgpio_bank *bank,
	const enum aspeed_sgpio_reg reg)
	{
	switch (reg) {
	case reg_val:
	return gpio->base + bank->val_regs + GPIO_VAL_VALUE;
	case reg_rdata:
	return gpio->base + bank->rdata_reg;
	case reg_irq_enable:
	return gpio->base + bank->irq_regs + GPIO_IRQ_ENABLE;
	case reg_irq_type0:
	return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE0;
	case reg_irq_type1:
	return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE1;
	case reg_irq_type2:
	return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE2;
	case reg_irq_status:
	return gpio->base + bank->irq_regs + GPIO_IRQ_STATUS;
	default:
	/* acturally if code runs to here, it's an error case */
	BUG();
	}
	}

	#define GPIO_BANK(x) ((x) >> 5)
	#define GPIO_OFFSET(x) ((x) & 0x1f)
	#define GPIO_BIT(x) BIT(GPIO_OFFSET(x))

	static const struct aspeed_sgpio_bank *to_bank(unsigned int offset)
	{
	unsigned int bank = GPIO_BANK(offset);

	WARN_ON(bank >= ARRAY_SIZE(aspeed_sgpio_banks));
	return &aspeed_sgpio_banks[bank];
	}

	static int aspeed_sgpio_get(struct gpio_chip *gc, unsigned int offset)
	{
	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_sgpio_bank *bank = to_bank(offset);
	unsigned long flags;
	enum aspeed_sgpio_reg reg;
	bool is_input;
	int rc = 0;

	spin_lock_irqsave(&gpio->lock, flags);

	is_input = gpio->dir_in[GPIO_BANK(offset)] & GPIO_BIT(offset);
	reg = is_input ? reg_val : reg_rdata;
	rc = !!(ioread32(bank_reg(gpio, bank, reg)) & GPIO_BIT(offset));

	spin_unlock_irqrestore(&gpio->lock, flags);

	return rc;
	}

	static void sgpio_set_value(struct gpio_chip *gc, unsigned int offset, int val)
	{
	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_sgpio_bank *bank = to_bank(offset);
	void __iomem *addr;
	u32 reg = 0;

	addr = bank_reg(gpio, bank, reg_val);
	reg = ioread32(addr);

	if (val)
	reg \|= GPIO_BIT(offset);
	else
	reg &= ~GPIO_BIT(offset);

	iowrite32(reg, addr);
	}

	static void aspeed_sgpio_set(struct gpio_chip *gc, unsigned int offset, int val)
	{
	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&gpio->lock, flags);

	sgpio_set_value(gc, offset, val);

	spin_unlock_irqrestore(&gpio->lock, flags);
	}

	static int aspeed_sgpio_dir_in(struct gpio_chip *gc, unsigned int offset)
	{
	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&gpio->lock, flags);
	gpio->dir_in[GPIO_BANK(offset)] \|= GPIO_BIT(offset);
	spin_unlock_irqrestore(&gpio->lock, flags);

	return 0;
	}

	static int aspeed_sgpio_dir_out(struct gpio_chip *gc, unsigned int offset, int val)
	{
	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&gpio->lock, flags);

	gpio->dir_in[GPIO_BANK(offset)] &= ~GPIO_BIT(offset);
	sgpio_set_value(gc, offset, val);

	spin_unlock_irqrestore(&gpio->lock, flags);

	return 0;
	}

	static int aspeed_sgpio_get_direction(struct gpio_chip *gc, unsigned int offset)
	{
	int dir_status;
	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&gpio->lock, flags);
	dir_status = gpio->dir_in[GPIO_BANK(offset)] & GPIO_BIT(offset);
	spin_unlock_irqrestore(&gpio->lock, flags);

	return dir_status;

	}

	static void irqd_to_aspeed_sgpio_data(struct irq_data *d,
	struct aspeed_sgpio **gpio,
	const struct aspeed_sgpio_bank **bank,
	u32 bit, int offset)
	{
	struct aspeed_sgpio *internal;

	*offset = irqd_to_hwirq(d);
	internal = irq_data_get_irq_chip_data(d);
	WARN_ON(!internal);

	*gpio = internal;
	bank = to_bank(offset);
	bit = GPIO_BIT(offset);
	}

	static void aspeed_sgpio_irq_ack(struct irq_data *d)
	{
	const struct aspeed_sgpio_bank *bank;
	struct aspeed_sgpio *gpio;
	unsigned long flags;
	void __iomem *status_addr;
	int offset;
	u32 bit;

	irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);

	status_addr = bank_reg(gpio, bank, reg_irq_status);

	spin_lock_irqsave(&gpio->lock, flags);

	iowrite32(bit, status_addr);

	spin_unlock_irqrestore(&gpio->lock, flags);
	}

	static void aspeed_sgpio_irq_set_mask(struct irq_data *d, bool set)
	{
	const struct aspeed_sgpio_bank *bank;
	struct aspeed_sgpio *gpio;
	unsigned long flags;
	u32 reg, bit;
	void __iomem *addr;
	int offset;

	irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
	addr = bank_reg(gpio, bank, reg_irq_enable);

	spin_lock_irqsave(&gpio->lock, flags);

	reg = ioread32(addr);
	if (set)
	reg \|= bit;
	else
	reg &= ~bit;

	iowrite32(reg, addr);

	spin_unlock_irqrestore(&gpio->lock, flags);
	}

	static void aspeed_sgpio_irq_mask(struct irq_data *d)
	{
	aspeed_sgpio_irq_set_mask(d, false);
	}

	static void aspeed_sgpio_irq_unmask(struct irq_data *d)
	{
	aspeed_sgpio_irq_set_mask(d, true);
	}

	static int aspeed_sgpio_set_type(struct irq_data *d, unsigned int type)
	{
	u32 type0 = 0;
	u32 type1 = 0;
	u32 type2 = 0;
	u32 bit, reg;
	const struct aspeed_sgpio_bank *bank;
	irq_flow_handler_t handler;
	struct aspeed_sgpio *gpio;
	unsigned long flags;
	void __iomem *addr;
	int offset;

	irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);

	switch (type & IRQ_TYPE_SENSE_MASK) {
	case IRQ_TYPE_EDGE_BOTH:
	type2 \|= bit;
	/* fall through */
	case IRQ_TYPE_EDGE_RISING:
	type0 \|= bit;
	/* fall through */
	case IRQ_TYPE_EDGE_FALLING:
	handler = handle_edge_irq;
	break;
	case IRQ_TYPE_LEVEL_HIGH:
	type0 \|= bit;
	/* fall through */
	case IRQ_TYPE_LEVEL_LOW:
	type1 \|= bit;
	handler = handle_level_irq;
	break;
	default:
	return -EINVAL;
	}

	spin_lock_irqsave(&gpio->lock, flags);

	addr = bank_reg(gpio, bank, reg_irq_type0);
	reg = ioread32(addr);
	reg = (reg & ~bit) \| type0;
	iowrite32(reg, addr);

	addr = bank_reg(gpio, bank, reg_irq_type1);
	reg = ioread32(addr);
	reg = (reg & ~bit) \| type1;
	iowrite32(reg, addr);

	addr = bank_reg(gpio, bank, reg_irq_type2);
	reg = ioread32(addr);
	reg = (reg & ~bit) \| type2;
	iowrite32(reg, addr);

	spin_unlock_irqrestore(&gpio->lock, flags);

	irq_set_handler_locked(d, handler);

	return 0;
	}

	static void aspeed_sgpio_irq_handler(struct irq_desc *desc)
	{
	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
	struct irq_chip *ic = irq_desc_get_chip(desc);
	struct aspeed_sgpio *data = gpiochip_get_data(gc);
	unsigned int i, p, girq;
	unsigned long reg;

	chained_irq_enter(ic, desc);

	for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
	const struct aspeed_sgpio_bank *bank = &aspeed_sgpio_banks[i];

	reg = ioread32(bank_reg(data, bank, reg_irq_status));

	for_each_set_bit(p, &reg, 32) {
	girq = irq_find_mapping(gc->irq.domain, i * 32 + p);
	generic_handle_irq(girq);
	}

	}

	chained_irq_exit(ic, desc);
	}

	static struct irq_chip aspeed_sgpio_irqchip = {
	.name = "aspeed-sgpio",
	.irq_ack = aspeed_sgpio_irq_ack,
	.irq_mask = aspeed_sgpio_irq_mask,
	.irq_unmask = aspeed_sgpio_irq_unmask,
	.irq_set_type = aspeed_sgpio_set_type,
	};

	static int aspeed_sgpio_setup_irqs(struct aspeed_sgpio *gpio,
	struct platform_device *pdev)
	{
	int rc, i;
	const struct aspeed_sgpio_bank *bank;
	struct gpio_irq_chip *irq;

	rc = platform_get_irq(pdev, 0);
	if (rc < 0)
	return rc;

	gpio->irq = rc;

	/* Disable IRQ and clear Interrupt status registers for all SGPIO Pins. */
	for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
	bank = &aspeed_sgpio_banks[i];
	/* disable irq enable bits */
	iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_enable));
	/* clear status bits */
	iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_status));
	}

	irq = &gpio->chip.irq;
	irq->chip = &aspeed_sgpio_irqchip;
	irq->handler = handle_bad_irq;
	irq->default_type = IRQ_TYPE_NONE;
	irq->parent_handler = aspeed_sgpio_irq_handler;
	irq->parent_handler_data = gpio;
	irq->parents = &gpio->irq;
	irq->num_parents = 1;

	/* set IRQ settings and Enable Interrupt */
	for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
	bank = &aspeed_sgpio_banks[i];
	/* set falling or level-low irq */
	iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_type0));
	/* trigger type is edge */
	iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_type1));
	/* dual edge trigger mode. */
	iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_type2));
	/* enable irq */
	iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_enable));
	}

	return 0;
	}

	static const struct of_device_id aspeed_sgpio_of_table[] = {
	{ .compatible = "aspeed,ast2400-sgpio" },
	{ .compatible = "aspeed,ast2500-sgpio" },
	{}
	};

	MODULE_DEVICE_TABLE(of, aspeed_sgpio_of_table);

	static int __init aspeed_sgpio_probe(struct platform_device *pdev)
	{
	struct aspeed_sgpio *gpio;
	u32 nr_gpios, sgpio_freq, sgpio_clk_div;
	int rc;
	unsigned long apb_freq;

	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
	if (!gpio)
	return -ENOMEM;

	gpio->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(gpio->base))
	return PTR_ERR(gpio->base);

	rc = of_property_read_u32(pdev->dev.of_node, "ngpios", &nr_gpios);
	if (rc < 0) {
	dev_err(&pdev->dev, "Could not read ngpios property\n");
	return -EINVAL;
	} else if (nr_gpios > MAX_NR_SGPIO) {
	dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d: %d\n",
	MAX_NR_SGPIO, nr_gpios);
	return -EINVAL;
	}

	rc = of_property_read_u32(pdev->dev.of_node, "bus-frequency", &sgpio_freq);
	if (rc < 0) {
	dev_err(&pdev->dev, "Could not read bus-frequency property\n");
	return -EINVAL;
	}

	gpio->pclk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(gpio->pclk)) {
	dev_err(&pdev->dev, "devm_clk_get failed\n");
	return PTR_ERR(gpio->pclk);
	}

	apb_freq = clk_get_rate(gpio->pclk);

	/*
	* From the datasheet,
	* SGPIO period = 1/PCLK * 2 * (GPIO254[31:16] + 1)
	* period = 2 * (GPIO254[31:16] + 1) / PCLK
	* frequency = 1 / (2 * (GPIO254[31:16] + 1) / PCLK)
	* frequency = PCLK / (2 * (GPIO254[31:16] + 1))
	* frequency * 2 * (GPIO254[31:16] + 1) = PCLK
	* GPIO254[31:16] = PCLK / (frequency * 2) - 1
	*/
	if (sgpio_freq == 0)
	return -EINVAL;

	sgpio_clk_div = (apb_freq / (sgpio_freq * 2)) - 1;

	if (sgpio_clk_div > (1 << 16) - 1)
	return -EINVAL;

	iowrite32(FIELD_PREP(ASPEED_SGPIO_CLK_DIV_MASK, sgpio_clk_div) \|
	FIELD_PREP(ASPEED_SGPIO_PINS_MASK, (nr_gpios / 8)) \|
	ASPEED_SGPIO_ENABLE,
	gpio->base + ASPEED_SGPIO_CTRL);

	spin_lock_init(&gpio->lock);

	gpio->chip.parent = &pdev->dev;
	gpio->chip.ngpio = nr_gpios;
	gpio->chip.direction_input = aspeed_sgpio_dir_in;
	gpio->chip.direction_output = aspeed_sgpio_dir_out;
	gpio->chip.get_direction = aspeed_sgpio_get_direction;
	gpio->chip.request = NULL;
	gpio->chip.free = NULL;
	gpio->chip.get = aspeed_sgpio_get;
	gpio->chip.set = aspeed_sgpio_set;
	gpio->chip.set_config = NULL;
	gpio->chip.label = dev_name(&pdev->dev);
	gpio->chip.base = -1;

	/* set all SGPIO pins as input (1). */
	memset(gpio->dir_in, 0xff, sizeof(gpio->dir_in));

	aspeed_sgpio_setup_irqs(gpio, pdev);

	rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
	if (rc < 0)
	return rc;

	return 0;
	}

	static struct platform_driver aspeed_sgpio_driver = {
	.driver = {
	.name = KBUILD_MODNAME,
	.of_match_table = aspeed_sgpio_of_table,
	},
	};

	module_platform_driver_probe(aspeed_sgpio_driver, aspeed_sgpio_probe);
	MODULE_DESCRIPTION("Aspeed Serial GPIO Driver");
	MODULE_LICENSE("GPL");