drivers/gpio/gpio-davinci.c - kernel/msm-4.9 - Gitiles

 /*
  * TI DaVinci GPIO Support
  *
  * Copyright (c) 2006-2007 David Brownell
  * Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  */
 #include <linux/gpio.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/gpio-davinci.h>
 #include <linux/irqchip/chained_irq.h>

 struct davinci_gpio_regs {
 	u32	dir;
 	u32	out_data;
 	u32	set_data;
 	u32	clr_data;
 	u32	in_data;
 	u32	set_rising;
 	u32	clr_rising;
 	u32	set_falling;
 	u32	clr_falling;
 	u32	intstat;
 };

 typedef struct irq_chip *(*gpio_get_irq_chip_cb_t)(unsigned int irq);

 #define BINTEN	0x8 /* GPIO Interrupt Per-Bank Enable Register */

 #define chip2controller(chip)	\
 	container_of(chip, struct davinci_gpio_controller, chip)

 static void __iomem *gpio_base;

 static struct davinci_gpio_regs __iomem *gpio2regs(unsigned gpio)
 {
 	void __iomem *ptr;

 	if (gpio < 32 * 1)
 		ptr = gpio_base + 0x10;
 	else if (gpio < 32 * 2)
 		ptr = gpio_base + 0x38;
 	else if (gpio < 32 * 3)
 		ptr = gpio_base + 0x60;
 	else if (gpio < 32 * 4)
 		ptr = gpio_base + 0x88;
 	else if (gpio < 32 * 5)
 		ptr = gpio_base + 0xb0;
 	else
 		ptr = NULL;
 	return ptr;
 }

 static inline struct davinci_gpio_regs __iomem *irq2regs(struct irq_data *d)
 {
 	struct davinci_gpio_regs __iomem *g;

 	g = (__force struct davinci_gpio_regs __iomem *)irq_data_get_irq_chip_data(d);

 	return g;
 }

 static int davinci_gpio_irq_setup(struct platform_device *pdev);

 /*--------------------------------------------------------------------------*/

 /* board setup code *MUST* setup pinmux and enable the GPIO clock. */
 static inline int __davinci_direction(struct gpio_chip *chip,
 			unsigned offset, bool out, int value)
 {
 	struct davinci_gpio_controller *d = chip2controller(chip);
 	struct davinci_gpio_regs __iomem *g = d->regs;
 	unsigned long flags;
 	u32 temp;
 	u32 mask = 1 << offset;

 	spin_lock_irqsave(&d->lock, flags);
 	temp = readl_relaxed(&g->dir);
 	if (out) {
 		temp &= ~mask;
 		writel_relaxed(mask, value ? &g->set_data : &g->clr_data);
 	} else {
 		temp |= mask;
 	}
 	writel_relaxed(temp, &g->dir);
 	spin_unlock_irqrestore(&d->lock, flags);

 	return 0;
 }

 static int davinci_direction_in(struct gpio_chip *chip, unsigned offset)
 {
 	return __davinci_direction(chip, offset, false, 0);
 }

 static int
 davinci_direction_out(struct gpio_chip *chip, unsigned offset, int value)
 {
 	return __davinci_direction(chip, offset, true, value);
 }

 /*
  * Read the pin's value (works even if it's set up as output);
  * returns zero/nonzero.
  *
  * Note that changes are synched to the GPIO clock, so reading values back
  * right after you've set them may give old values.
  */
 static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	struct davinci_gpio_controller *d = chip2controller(chip);
 	struct davinci_gpio_regs __iomem *g = d->regs;

 	return (1 << offset) & readl_relaxed(&g->in_data);
 }

 /*
  * Assuming the pin is muxed as a gpio output, set its output value.
  */
 static void
 davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct davinci_gpio_controller *d = chip2controller(chip);
 	struct davinci_gpio_regs __iomem *g = d->regs;

 	writel_relaxed((1 << offset), value ? &g->set_data : &g->clr_data);
 }

 static struct davinci_gpio_platform_data *
 davinci_gpio_get_pdata(struct platform_device *pdev)
 {
 	struct device_node *dn = pdev->dev.of_node;
 	struct davinci_gpio_platform_data *pdata;
 	int ret;
 	u32 val;

 	if (!IS_ENABLED(CONFIG_OF) || !pdev->dev.of_node)
 		return pdev->dev.platform_data;

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

 	ret = of_property_read_u32(dn, "ti,ngpio", &val);
 	if (ret)
 		goto of_err;

 	pdata->ngpio = val;

 	ret = of_property_read_u32(dn, "ti,davinci-gpio-unbanked", &val);
 	if (ret)
 		goto of_err;

 	pdata->gpio_unbanked = val;

 	return pdata;

 of_err:
 	dev_err(&pdev->dev, "Populating pdata from DT failed: err %d\n", ret);
 	return NULL;
 }

 #ifdef CONFIG_OF_GPIO
 static int davinci_gpio_of_xlate(struct gpio_chip *gc,
 			     const struct of_phandle_args *gpiospec,
 			     u32 *flags)
 {
 	struct davinci_gpio_controller *chips = dev_get_drvdata(gc->dev);
 	struct davinci_gpio_platform_data *pdata = dev_get_platdata(gc->dev);

 	if (gpiospec->args[0] > pdata->ngpio)
 		return -EINVAL;

 	if (gc != &chips[gpiospec->args[0] / 32].chip)
 		return -EINVAL;

 	if (flags)
 		*flags = gpiospec->args[1];

 	return gpiospec->args[0] % 32;
 }
 #endif

 static int davinci_gpio_probe(struct platform_device *pdev)
 {
 	int i, base;
 	unsigned ngpio;
 	struct davinci_gpio_controller *chips;
 	struct davinci_gpio_platform_data *pdata;
 	struct davinci_gpio_regs __iomem *regs;
 	struct device *dev = &pdev->dev;
 	struct resource *res;

 	pdata = davinci_gpio_get_pdata(pdev);
 	if (!pdata) {
 		dev_err(dev, "No platform data found\n");
 		return -EINVAL;
 	}

 	dev->platform_data = pdata;

 	/*
 	 * The gpio banks conceptually expose a segmented bitmap,
 	 * and "ngpio" is one more than the largest zero-based
 	 * bit index that's valid.
 	 */
 	ngpio = pdata->ngpio;
 	if (ngpio == 0) {
 		dev_err(dev, "How many GPIOs?\n");
 		return -EINVAL;
 	}

 	if (WARN_ON(ARCH_NR_GPIOS < ngpio))
 		ngpio = ARCH_NR_GPIOS;

 	chips = devm_kzalloc(dev,
 			     ngpio * sizeof(struct davinci_gpio_controller),
 			     GFP_KERNEL);
 	if (!chips)
 		return -ENOMEM;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	gpio_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(gpio_base))
 		return PTR_ERR(gpio_base);

 	for (i = 0, base = 0; base < ngpio; i++, base += 32) {
 		chips[i].chip.label = "DaVinci";

 		chips[i].chip.direction_input = davinci_direction_in;
 		chips[i].chip.get = davinci_gpio_get;
 		chips[i].chip.direction_output = davinci_direction_out;
 		chips[i].chip.set = davinci_gpio_set;

 		chips[i].chip.base = base;
 		chips[i].chip.ngpio = ngpio - base;
 		if (chips[i].chip.ngpio > 32)
 			chips[i].chip.ngpio = 32;

 #ifdef CONFIG_OF_GPIO
 		chips[i].chip.of_gpio_n_cells = 2;
 		chips[i].chip.of_xlate = davinci_gpio_of_xlate;
 		chips[i].chip.dev = dev;
 		chips[i].chip.of_node = dev->of_node;
 #endif
 		spin_lock_init(&chips[i].lock);

 		regs = gpio2regs(base);
 		chips[i].regs = regs;
 		chips[i].set_data = &regs->set_data;
 		chips[i].clr_data = &regs->clr_data;
 		chips[i].in_data = &regs->in_data;

 		gpiochip_add(&chips[i].chip);
 	}

 	platform_set_drvdata(pdev, chips);
 	davinci_gpio_irq_setup(pdev);
 	return 0;
 }

 /*--------------------------------------------------------------------------*/
 /*
  * We expect irqs will normally be set up as input pins, but they can also be
  * used as output pins ... which is convenient for testing.
  *
  * NOTE:  The first few GPIOs also have direct INTC hookups in addition
  * to their GPIOBNK0 irq, with a bit less overhead.
  *
  * All those INTC hookups (direct, plus several IRQ banks) can also
  * serve as EDMA event triggers.
  */

 static void gpio_irq_disable(struct irq_data *d)
 {
 	struct davinci_gpio_regs __iomem *g = irq2regs(d);
 	u32 mask = (u32) irq_data_get_irq_handler_data(d);

 	writel_relaxed(mask, &g->clr_falling);
 	writel_relaxed(mask, &g->clr_rising);
 }

 static void gpio_irq_enable(struct irq_data *d)
 {
 	struct davinci_gpio_regs __iomem *g = irq2regs(d);
 	u32 mask = (u32) irq_data_get_irq_handler_data(d);
 	unsigned status = irqd_get_trigger_type(d);

 	status &= IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;
 	if (!status)
 		status = IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;

 	if (status & IRQ_TYPE_EDGE_FALLING)
 		writel_relaxed(mask, &g->set_falling);
 	if (status & IRQ_TYPE_EDGE_RISING)
 		writel_relaxed(mask, &g->set_rising);
 }

 static int gpio_irq_type(struct irq_data *d, unsigned trigger)
 {
 	if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
 		return -EINVAL;

 	return 0;
 }

 static struct irq_chip gpio_irqchip = {
 	.name		= "GPIO",
 	.irq_enable	= gpio_irq_enable,
 	.irq_disable	= gpio_irq_disable,
 	.irq_set_type	= gpio_irq_type,
 	.flags		= IRQCHIP_SET_TYPE_MASKED,
 };

 static void
 gpio_irq_handler(unsigned __irq, struct irq_desc *desc)
 {
 	unsigned int irq = irq_desc_get_irq(desc);
 	struct davinci_gpio_regs __iomem *g;
 	u32 mask = 0xffff;
 	struct davinci_gpio_controller *d;

 	d = (struct davinci_gpio_controller *)irq_desc_get_handler_data(desc);
 	g = (struct davinci_gpio_regs __iomem *)d->regs;

 	/* we only care about one bank */
 	if (irq & 1)
 		mask <<= 16;

 	/* temporarily mask (level sensitive) parent IRQ */
 	chained_irq_enter(irq_desc_get_chip(desc), desc);
 	while (1) {
 		u32		status;
 		int		bit;

 		/* ack any irqs */
 		status = readl_relaxed(&g->intstat) & mask;
 		if (!status)
 			break;
 		writel_relaxed(status, &g->intstat);

 		/* now demux them to the right lowlevel handler */

 		while (status) {
 			bit = __ffs(status);
 			status &= ~BIT(bit);
 			generic_handle_irq(
 				irq_find_mapping(d->irq_domain,
 						 d->chip.base + bit));
 		}
 	}
 	chained_irq_exit(irq_desc_get_chip(desc), desc);
 	/* now it may re-trigger */
 }

 static int gpio_to_irq_banked(struct gpio_chip *chip, unsigned offset)
 {
 	struct davinci_gpio_controller *d = chip2controller(chip);

 	if (d->irq_domain)
 		return irq_create_mapping(d->irq_domain, d->chip.base + offset);
 	else
 		return -ENXIO;
 }

 static int gpio_to_irq_unbanked(struct gpio_chip *chip, unsigned offset)
 {
 	struct davinci_gpio_controller *d = chip2controller(chip);

 	/*
 	 * NOTE:  we assume for now that only irqs in the first gpio_chip
 	 * can provide direct-mapped IRQs to AINTC (up to 32 GPIOs).
 	 */
 	if (offset < d->gpio_unbanked)
 		return d->gpio_irq + offset;
 	else
 		return -ENODEV;
 }

 static int gpio_irq_type_unbanked(struct irq_data *data, unsigned trigger)
 {
 	struct davinci_gpio_controller *d;
 	struct davinci_gpio_regs __iomem *g;
 	u32 mask;

 	d = (struct davinci_gpio_controller *)irq_data_get_irq_handler_data(data);
 	g = (struct davinci_gpio_regs __iomem *)d->regs;
 	mask = __gpio_mask(data->irq - d->gpio_irq);

 	if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
 		return -EINVAL;

 	writel_relaxed(mask, (trigger & IRQ_TYPE_EDGE_FALLING)
 		     ? &g->set_falling : &g->clr_falling);
 	writel_relaxed(mask, (trigger & IRQ_TYPE_EDGE_RISING)
 		     ? &g->set_rising : &g->clr_rising);

 	return 0;
 }

 static int
 davinci_gpio_irq_map(struct irq_domain *d, unsigned int irq,
 		     irq_hw_number_t hw)
 {
 	struct davinci_gpio_regs __iomem *g = gpio2regs(hw);

 	irq_set_chip_and_handler_name(irq, &gpio_irqchip, handle_simple_irq,
 				"davinci_gpio");
 	irq_set_irq_type(irq, IRQ_TYPE_NONE);
 	irq_set_chip_data(irq, (__force void *)g);
 	irq_set_handler_data(irq, (void *)__gpio_mask(hw));

 	return 0;
 }

 static const struct irq_domain_ops davinci_gpio_irq_ops = {
 	.map = davinci_gpio_irq_map,
 	.xlate = irq_domain_xlate_onetwocell,
 };

 static struct irq_chip *davinci_gpio_get_irq_chip(unsigned int irq)
 {
 	static struct irq_chip_type gpio_unbanked;

 	gpio_unbanked = *container_of(irq_get_chip(irq),
 				      struct irq_chip_type, chip);

 	return &gpio_unbanked.chip;
 };

 static struct irq_chip *keystone_gpio_get_irq_chip(unsigned int irq)
 {
 	static struct irq_chip gpio_unbanked;

 	gpio_unbanked = *irq_get_chip(irq);
 	return &gpio_unbanked;
 };

 static const struct of_device_id davinci_gpio_ids[];

 /*
  * NOTE:  for suspend/resume, probably best to make a platform_device with
  * suspend_late/resume_resume calls hooking into results of the set_wake()
  * calls ... so if no gpios are wakeup events the clock can be disabled,
  * with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
  * (dm6446) can be set appropriately for GPIOV33 pins.
  */

 static int davinci_gpio_irq_setup(struct platform_device *pdev)
 {
 	unsigned	gpio, bank;
 	int		irq;
 	struct clk	*clk;
 	u32		binten = 0;
 	unsigned	ngpio, bank_irq;
 	struct device *dev = &pdev->dev;
 	struct resource	*res;
 	struct davinci_gpio_controller *chips = platform_get_drvdata(pdev);
 	struct davinci_gpio_platform_data *pdata = dev->platform_data;
 	struct davinci_gpio_regs __iomem *g;
 	struct irq_domain	*irq_domain = NULL;
 	const struct of_device_id *match;
 	struct irq_chip *irq_chip;
 	gpio_get_irq_chip_cb_t gpio_get_irq_chip;

 	/*
 	 * Use davinci_gpio_get_irq_chip by default to handle non DT cases
 	 */
 	gpio_get_irq_chip = davinci_gpio_get_irq_chip;
 	match = of_match_device(of_match_ptr(davinci_gpio_ids),
 				dev);
 	if (match)
 		gpio_get_irq_chip = (gpio_get_irq_chip_cb_t)match->data;

 	ngpio = pdata->ngpio;
 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (!res) {
 		dev_err(dev, "Invalid IRQ resource\n");
 		return -EBUSY;
 	}

 	bank_irq = res->start;

 	if (!bank_irq) {
 		dev_err(dev, "Invalid IRQ resource\n");
 		return -ENODEV;
 	}

 	clk = devm_clk_get(dev, "gpio");
 	if (IS_ERR(clk)) {
 		printk(KERN_ERR "Error %ld getting gpio clock?\n",
 		       PTR_ERR(clk));
 		return PTR_ERR(clk);
 	}
 	clk_prepare_enable(clk);

 	if (!pdata->gpio_unbanked) {
 		irq = irq_alloc_descs(-1, 0, ngpio, 0);
 		if (irq < 0) {
 			dev_err(dev, "Couldn't allocate IRQ numbers\n");
 			return irq;
 		}

 		irq_domain = irq_domain_add_legacy(NULL, ngpio, irq, 0,
 							&davinci_gpio_irq_ops,
 							chips);
 		if (!irq_domain) {
 			dev_err(dev, "Couldn't register an IRQ domain\n");
 			return -ENODEV;
 		}
 	}

 	/*
 	 * Arrange gpio_to_irq() support, handling either direct IRQs or
 	 * banked IRQs.  Having GPIOs in the first GPIO bank use direct
 	 * IRQs, while the others use banked IRQs, would need some setup
 	 * tweaks to recognize hardware which can do that.
 	 */
 	for (gpio = 0, bank = 0; gpio < ngpio; bank++, gpio += 32) {
 		chips[bank].chip.to_irq = gpio_to_irq_banked;
 		chips[bank].irq_domain = irq_domain;
 	}

 	/*
 	 * AINTC can handle direct/unbanked IRQs for GPIOs, with the GPIO
 	 * controller only handling trigger modes.  We currently assume no
 	 * IRQ mux conflicts; gpio_irq_type_unbanked() is only for GPIOs.
 	 */
 	if (pdata->gpio_unbanked) {
 		/* pass "bank 0" GPIO IRQs to AINTC */
 		chips[0].chip.to_irq = gpio_to_irq_unbanked;
 		chips[0].gpio_irq = bank_irq;
 		chips[0].gpio_unbanked = pdata->gpio_unbanked;
 		binten = GENMASK(pdata->gpio_unbanked / 16, 0);

 		/* AINTC handles mask/unmask; GPIO handles triggering */
 		irq = bank_irq;
 		irq_chip = gpio_get_irq_chip(irq);
 		irq_chip->name = "GPIO-AINTC";
 		irq_chip->irq_set_type = gpio_irq_type_unbanked;

 		/* default trigger: both edges */
 		g = gpio2regs(0);
 		writel_relaxed(~0, &g->set_falling);
 		writel_relaxed(~0, &g->set_rising);

 		/* set the direct IRQs up to use that irqchip */
 		for (gpio = 0; gpio < pdata->gpio_unbanked; gpio++, irq++) {
 			irq_set_chip(irq, irq_chip);
 			irq_set_handler_data(irq, &chips[gpio / 32]);
 			irq_set_status_flags(irq, IRQ_TYPE_EDGE_BOTH);
 		}

 		goto done;
 	}

 	/*
 	 * Or, AINTC can handle IRQs for banks of 16 GPIO IRQs, which we
 	 * then chain through our own handler.
 	 */
 	for (gpio = 0, bank = 0; gpio < ngpio; bank++, bank_irq++, gpio += 16) {
 		/* disabled by default, enabled only as needed */
 		g = gpio2regs(gpio);
 		writel_relaxed(~0, &g->clr_falling);
 		writel_relaxed(~0, &g->clr_rising);

 		/*
 		 * Each chip handles 32 gpios, and each irq bank consists of 16
 		 * gpio irqs. Pass the irq bank's corresponding controller to
 		 * the chained irq handler.
 		 */
 		irq_set_chained_handler_and_data(bank_irq, gpio_irq_handler,
 						 &chips[gpio / 32]);

 		binten |= BIT(bank);
 	}

 done:
 	/*
 	 * BINTEN -- per-bank interrupt enable. genirq would also let these
 	 * bits be set/cleared dynamically.
 	 */
 	writel_relaxed(binten, gpio_base + BINTEN);

 	return 0;
 }

 #if IS_ENABLED(CONFIG_OF)
 static const struct of_device_id davinci_gpio_ids[] = {
 	{ .compatible = "ti,keystone-gpio", keystone_gpio_get_irq_chip},
 	{ .compatible = "ti,dm6441-gpio", davinci_gpio_get_irq_chip},
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, davinci_gpio_ids);
 #endif

 static struct platform_driver davinci_gpio_driver = {
 	.probe		= davinci_gpio_probe,
 	.driver		= {
 		.name		= "davinci_gpio",
 		.of_match_table	= of_match_ptr(davinci_gpio_ids),
 	},
 };

 /**
  * GPIO driver registration needs to be done before machine_init functions
  * access GPIO. Hence davinci_gpio_drv_reg() is a postcore_initcall.
  */
 static int __init davinci_gpio_drv_reg(void)
 {
 	return platform_driver_register(&davinci_gpio_driver);
 }
 postcore_initcall(davinci_gpio_drv_reg);
	/*
	* TI DaVinci GPIO Support
	*
	* Copyright (c) 2006-2007 David Brownell
	* Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*/
	#include <linux/gpio.h>
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/irq.h>
	#include <linux/irqdomain.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/platform_data/gpio-davinci.h>
	#include <linux/irqchip/chained_irq.h>

	struct davinci_gpio_regs {
	u32 dir;
	u32 out_data;
	u32 set_data;
	u32 clr_data;
	u32 in_data;
	u32 set_rising;
	u32 clr_rising;
	u32 set_falling;
	u32 clr_falling;
	u32 intstat;
	};

	typedef struct irq_chip (gpio_get_irq_chip_cb_t)(unsigned int irq);

	#define BINTEN 0x8 /* GPIO Interrupt Per-Bank Enable Register */

	#define chip2controller(chip) \
	container_of(chip, struct davinci_gpio_controller, chip)

	static void __iomem *gpio_base;

	static struct davinci_gpio_regs __iomem *gpio2regs(unsigned gpio)
	{
	void __iomem *ptr;

	if (gpio < 32 * 1)
	ptr = gpio_base + 0x10;
	else if (gpio < 32 * 2)
	ptr = gpio_base + 0x38;
	else if (gpio < 32 * 3)
	ptr = gpio_base + 0x60;
	else if (gpio < 32 * 4)
	ptr = gpio_base + 0x88;
	else if (gpio < 32 * 5)
	ptr = gpio_base + 0xb0;
	else
	ptr = NULL;
	return ptr;
	}

	static inline struct davinci_gpio_regs __iomem irq2regs(struct irq_data d)
	{
	struct davinci_gpio_regs __iomem *g;

	g = (__force struct davinci_gpio_regs __iomem *)irq_data_get_irq_chip_data(d);

	return g;
	}

	static int davinci_gpio_irq_setup(struct platform_device *pdev);

	/--------------------------------------------------------------------------/

	/* board setup code MUST setup pinmux and enable the GPIO clock. */
	static inline int __davinci_direction(struct gpio_chip *chip,
	unsigned offset, bool out, int value)
	{
	struct davinci_gpio_controller *d = chip2controller(chip);
	struct davinci_gpio_regs __iomem *g = d->regs;
	unsigned long flags;
	u32 temp;
	u32 mask = 1 << offset;

	spin_lock_irqsave(&d->lock, flags);
	temp = readl_relaxed(&g->dir);
	if (out) {
	temp &= ~mask;
	writel_relaxed(mask, value ? &g->set_data : &g->clr_data);
	} else {
	temp \|= mask;
	}
	writel_relaxed(temp, &g->dir);
	spin_unlock_irqrestore(&d->lock, flags);

	return 0;
	}

	static int davinci_direction_in(struct gpio_chip *chip, unsigned offset)
	{
	return __davinci_direction(chip, offset, false, 0);
	}

	static int
	davinci_direction_out(struct gpio_chip *chip, unsigned offset, int value)
	{
	return __davinci_direction(chip, offset, true, value);
	}

	/*
	* Read the pin's value (works even if it's set up as output);
	* returns zero/nonzero.
	*
	* Note that changes are synched to the GPIO clock, so reading values back
	* right after you've set them may give old values.
	*/
	static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
	{
	struct davinci_gpio_controller *d = chip2controller(chip);
	struct davinci_gpio_regs __iomem *g = d->regs;

	return (1 << offset) & readl_relaxed(&g->in_data);
	}

	/*
	* Assuming the pin is muxed as a gpio output, set its output value.
	*/
	static void
	davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
	{
	struct davinci_gpio_controller *d = chip2controller(chip);
	struct davinci_gpio_regs __iomem *g = d->regs;

	writel_relaxed((1 << offset), value ? &g->set_data : &g->clr_data);
	}

	static struct davinci_gpio_platform_data *
	davinci_gpio_get_pdata(struct platform_device *pdev)
	{
	struct device_node *dn = pdev->dev.of_node;
	struct davinci_gpio_platform_data *pdata;
	int ret;
	u32 val;

	if (!IS_ENABLED(CONFIG_OF) \|\| !pdev->dev.of_node)
	return pdev->dev.platform_data;

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

	ret = of_property_read_u32(dn, "ti,ngpio", &val);
	if (ret)
	goto of_err;

	pdata->ngpio = val;

	ret = of_property_read_u32(dn, "ti,davinci-gpio-unbanked", &val);
	if (ret)
	goto of_err;

	pdata->gpio_unbanked = val;

	return pdata;

	of_err:
	dev_err(&pdev->dev, "Populating pdata from DT failed: err %d\n", ret);
	return NULL;
	}

	#ifdef CONFIG_OF_GPIO
	static int davinci_gpio_of_xlate(struct gpio_chip *gc,
	const struct of_phandle_args *gpiospec,
	u32 *flags)
	{
	struct davinci_gpio_controller *chips = dev_get_drvdata(gc->dev);
	struct davinci_gpio_platform_data *pdata = dev_get_platdata(gc->dev);

	if (gpiospec->args[0] > pdata->ngpio)
	return -EINVAL;

	if (gc != &chips[gpiospec->args[0] / 32].chip)
	return -EINVAL;

	if (flags)
	*flags = gpiospec->args[1];

	return gpiospec->args[0] % 32;
	}
	#endif

	static int davinci_gpio_probe(struct platform_device *pdev)
	{
	int i, base;
	unsigned ngpio;
	struct davinci_gpio_controller *chips;
	struct davinci_gpio_platform_data *pdata;
	struct davinci_gpio_regs __iomem *regs;
	struct device *dev = &pdev->dev;
	struct resource *res;

	pdata = davinci_gpio_get_pdata(pdev);
	if (!pdata) {
	dev_err(dev, "No platform data found\n");
	return -EINVAL;
	}

	dev->platform_data = pdata;

	/*
	* The gpio banks conceptually expose a segmented bitmap,
	* and "ngpio" is one more than the largest zero-based
	* bit index that's valid.
	*/
	ngpio = pdata->ngpio;
	if (ngpio == 0) {
	dev_err(dev, "How many GPIOs?\n");
	return -EINVAL;
	}

	if (WARN_ON(ARCH_NR_GPIOS < ngpio))
	ngpio = ARCH_NR_GPIOS;

	chips = devm_kzalloc(dev,
	ngpio * sizeof(struct davinci_gpio_controller),
	GFP_KERNEL);
	if (!chips)
	return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	gpio_base = devm_ioremap_resource(dev, res);
	if (IS_ERR(gpio_base))
	return PTR_ERR(gpio_base);

	for (i = 0, base = 0; base < ngpio; i++, base += 32) {
	chips[i].chip.label = "DaVinci";

	chips[i].chip.direction_input = davinci_direction_in;
	chips[i].chip.get = davinci_gpio_get;
	chips[i].chip.direction_output = davinci_direction_out;
	chips[i].chip.set = davinci_gpio_set;

	chips[i].chip.base = base;
	chips[i].chip.ngpio = ngpio - base;
	if (chips[i].chip.ngpio > 32)
	chips[i].chip.ngpio = 32;

	#ifdef CONFIG_OF_GPIO
	chips[i].chip.of_gpio_n_cells = 2;
	chips[i].chip.of_xlate = davinci_gpio_of_xlate;
	chips[i].chip.dev = dev;
	chips[i].chip.of_node = dev->of_node;
	#endif
	spin_lock_init(&chips[i].lock);

	regs = gpio2regs(base);
	chips[i].regs = regs;
	chips[i].set_data = &regs->set_data;
	chips[i].clr_data = &regs->clr_data;
	chips[i].in_data = &regs->in_data;

	gpiochip_add(&chips[i].chip);
	}

	platform_set_drvdata(pdev, chips);
	davinci_gpio_irq_setup(pdev);
	return 0;
	}

	/--------------------------------------------------------------------------/
	/*
	* We expect irqs will normally be set up as input pins, but they can also be
	* used as output pins ... which is convenient for testing.
	*
	* NOTE: The first few GPIOs also have direct INTC hookups in addition
	* to their GPIOBNK0 irq, with a bit less overhead.
	*
	* All those INTC hookups (direct, plus several IRQ banks) can also
	* serve as EDMA event triggers.
	*/

	static void gpio_irq_disable(struct irq_data *d)
	{
	struct davinci_gpio_regs __iomem *g = irq2regs(d);
	u32 mask = (u32) irq_data_get_irq_handler_data(d);

	writel_relaxed(mask, &g->clr_falling);
	writel_relaxed(mask, &g->clr_rising);
	}

	static void gpio_irq_enable(struct irq_data *d)
	{
	struct davinci_gpio_regs __iomem *g = irq2regs(d);
	u32 mask = (u32) irq_data_get_irq_handler_data(d);
	unsigned status = irqd_get_trigger_type(d);

	status &= IRQ_TYPE_EDGE_FALLING \| IRQ_TYPE_EDGE_RISING;
	if (!status)
	status = IRQ_TYPE_EDGE_FALLING \| IRQ_TYPE_EDGE_RISING;

	if (status & IRQ_TYPE_EDGE_FALLING)
	writel_relaxed(mask, &g->set_falling);
	if (status & IRQ_TYPE_EDGE_RISING)
	writel_relaxed(mask, &g->set_rising);
	}

	static int gpio_irq_type(struct irq_data *d, unsigned trigger)
	{
	if (trigger & ~(IRQ_TYPE_EDGE_FALLING \| IRQ_TYPE_EDGE_RISING))
	return -EINVAL;

	return 0;
	}

	static struct irq_chip gpio_irqchip = {
	.name = "GPIO",
	.irq_enable = gpio_irq_enable,
	.irq_disable = gpio_irq_disable,
	.irq_set_type = gpio_irq_type,
	.flags = IRQCHIP_SET_TYPE_MASKED,
	};

	static void
	gpio_irq_handler(unsigned __irq, struct irq_desc *desc)
	{
	unsigned int irq = irq_desc_get_irq(desc);
	struct davinci_gpio_regs __iomem *g;
	u32 mask = 0xffff;
	struct davinci_gpio_controller *d;

	d = (struct davinci_gpio_controller *)irq_desc_get_handler_data(desc);
	g = (struct davinci_gpio_regs __iomem *)d->regs;

	/* we only care about one bank */
	if (irq & 1)
	mask <<= 16;

	/* temporarily mask (level sensitive) parent IRQ */
	chained_irq_enter(irq_desc_get_chip(desc), desc);
	while (1) {
	u32 status;
	int bit;

	/* ack any irqs */
	status = readl_relaxed(&g->intstat) & mask;
	if (!status)
	break;
	writel_relaxed(status, &g->intstat);

	/* now demux them to the right lowlevel handler */

	while (status) {
	bit = __ffs(status);
	status &= ~BIT(bit);
	generic_handle_irq(
	irq_find_mapping(d->irq_domain,
	d->chip.base + bit));
	}
	}
	chained_irq_exit(irq_desc_get_chip(desc), desc);
	/* now it may re-trigger */
	}

	static int gpio_to_irq_banked(struct gpio_chip *chip, unsigned offset)
	{
	struct davinci_gpio_controller *d = chip2controller(chip);

	if (d->irq_domain)
	return irq_create_mapping(d->irq_domain, d->chip.base + offset);
	else
	return -ENXIO;
	}

	static int gpio_to_irq_unbanked(struct gpio_chip *chip, unsigned offset)
	{
	struct davinci_gpio_controller *d = chip2controller(chip);

	/*
	* NOTE: we assume for now that only irqs in the first gpio_chip
	* can provide direct-mapped IRQs to AINTC (up to 32 GPIOs).
	*/
	if (offset < d->gpio_unbanked)
	return d->gpio_irq + offset;
	else
	return -ENODEV;
	}

	static int gpio_irq_type_unbanked(struct irq_data *data, unsigned trigger)
	{
	struct davinci_gpio_controller *d;
	struct davinci_gpio_regs __iomem *g;
	u32 mask;

	d = (struct davinci_gpio_controller *)irq_data_get_irq_handler_data(data);
	g = (struct davinci_gpio_regs __iomem *)d->regs;
	mask = __gpio_mask(data->irq - d->gpio_irq);

	if (trigger & ~(IRQ_TYPE_EDGE_FALLING \| IRQ_TYPE_EDGE_RISING))
	return -EINVAL;

	writel_relaxed(mask, (trigger & IRQ_TYPE_EDGE_FALLING)
	? &g->set_falling : &g->clr_falling);
	writel_relaxed(mask, (trigger & IRQ_TYPE_EDGE_RISING)
	? &g->set_rising : &g->clr_rising);

	return 0;
	}

	static int
	davinci_gpio_irq_map(struct irq_domain *d, unsigned int irq,
	irq_hw_number_t hw)
	{
	struct davinci_gpio_regs __iomem *g = gpio2regs(hw);

	irq_set_chip_and_handler_name(irq, &gpio_irqchip, handle_simple_irq,
	"davinci_gpio");
	irq_set_irq_type(irq, IRQ_TYPE_NONE);
	irq_set_chip_data(irq, (__force void *)g);
	irq_set_handler_data(irq, (void *)__gpio_mask(hw));

	return 0;
	}

	static const struct irq_domain_ops davinci_gpio_irq_ops = {
	.map = davinci_gpio_irq_map,
	.xlate = irq_domain_xlate_onetwocell,
	};

	static struct irq_chip *davinci_gpio_get_irq_chip(unsigned int irq)
	{
	static struct irq_chip_type gpio_unbanked;

	gpio_unbanked = *container_of(irq_get_chip(irq),
	struct irq_chip_type, chip);

	return &gpio_unbanked.chip;
	};

	static struct irq_chip *keystone_gpio_get_irq_chip(unsigned int irq)
	{
	static struct irq_chip gpio_unbanked;

	gpio_unbanked = *irq_get_chip(irq);
	return &gpio_unbanked;
	};

	static const struct of_device_id davinci_gpio_ids[];

	/*
	* NOTE: for suspend/resume, probably best to make a platform_device with
	* suspend_late/resume_resume calls hooking into results of the set_wake()
	* calls ... so if no gpios are wakeup events the clock can be disabled,
	* with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
	* (dm6446) can be set appropriately for GPIOV33 pins.
	*/

	static int davinci_gpio_irq_setup(struct platform_device *pdev)
	{
	unsigned gpio, bank;
	int irq;
	struct clk *clk;
	u32 binten = 0;
	unsigned ngpio, bank_irq;
	struct device *dev = &pdev->dev;
	struct resource *res;
	struct davinci_gpio_controller *chips = platform_get_drvdata(pdev);
	struct davinci_gpio_platform_data *pdata = dev->platform_data;
	struct davinci_gpio_regs __iomem *g;
	struct irq_domain *irq_domain = NULL;
	const struct of_device_id *match;
	struct irq_chip *irq_chip;
	gpio_get_irq_chip_cb_t gpio_get_irq_chip;

	/*
	* Use davinci_gpio_get_irq_chip by default to handle non DT cases
	*/
	gpio_get_irq_chip = davinci_gpio_get_irq_chip;
	match = of_match_device(of_match_ptr(davinci_gpio_ids),
	dev);
	if (match)
	gpio_get_irq_chip = (gpio_get_irq_chip_cb_t)match->data;

	ngpio = pdata->ngpio;
	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res) {
	dev_err(dev, "Invalid IRQ resource\n");
	return -EBUSY;
	}

	bank_irq = res->start;

	if (!bank_irq) {
	dev_err(dev, "Invalid IRQ resource\n");
	return -ENODEV;
	}

	clk = devm_clk_get(dev, "gpio");
	if (IS_ERR(clk)) {
	printk(KERN_ERR "Error %ld getting gpio clock?\n",
	PTR_ERR(clk));
	return PTR_ERR(clk);
	}
	clk_prepare_enable(clk);

	if (!pdata->gpio_unbanked) {
	irq = irq_alloc_descs(-1, 0, ngpio, 0);
	if (irq < 0) {
	dev_err(dev, "Couldn't allocate IRQ numbers\n");
	return irq;
	}

	irq_domain = irq_domain_add_legacy(NULL, ngpio, irq, 0,
	&davinci_gpio_irq_ops,
	chips);
	if (!irq_domain) {
	dev_err(dev, "Couldn't register an IRQ domain\n");
	return -ENODEV;
	}
	}

	/*
	* Arrange gpio_to_irq() support, handling either direct IRQs or
	* banked IRQs. Having GPIOs in the first GPIO bank use direct
	* IRQs, while the others use banked IRQs, would need some setup
	* tweaks to recognize hardware which can do that.
	*/
	for (gpio = 0, bank = 0; gpio < ngpio; bank++, gpio += 32) {
	chips[bank].chip.to_irq = gpio_to_irq_banked;
	chips[bank].irq_domain = irq_domain;
	}

	/*
	* AINTC can handle direct/unbanked IRQs for GPIOs, with the GPIO
	* controller only handling trigger modes. We currently assume no
	* IRQ mux conflicts; gpio_irq_type_unbanked() is only for GPIOs.
	*/
	if (pdata->gpio_unbanked) {
	/* pass "bank 0" GPIO IRQs to AINTC */
	chips[0].chip.to_irq = gpio_to_irq_unbanked;
	chips[0].gpio_irq = bank_irq;
	chips[0].gpio_unbanked = pdata->gpio_unbanked;
	binten = GENMASK(pdata->gpio_unbanked / 16, 0);

	/* AINTC handles mask/unmask; GPIO handles triggering */
	irq = bank_irq;
	irq_chip = gpio_get_irq_chip(irq);
	irq_chip->name = "GPIO-AINTC";
	irq_chip->irq_set_type = gpio_irq_type_unbanked;

	/* default trigger: both edges */
	g = gpio2regs(0);
	writel_relaxed(~0, &g->set_falling);
	writel_relaxed(~0, &g->set_rising);

	/* set the direct IRQs up to use that irqchip */
	for (gpio = 0; gpio < pdata->gpio_unbanked; gpio++, irq++) {
	irq_set_chip(irq, irq_chip);
	irq_set_handler_data(irq, &chips[gpio / 32]);
	irq_set_status_flags(irq, IRQ_TYPE_EDGE_BOTH);
	}

	goto done;
	}

	/*
	* Or, AINTC can handle IRQs for banks of 16 GPIO IRQs, which we
	* then chain through our own handler.
	*/
	for (gpio = 0, bank = 0; gpio < ngpio; bank++, bank_irq++, gpio += 16) {
	/* disabled by default, enabled only as needed */
	g = gpio2regs(gpio);
	writel_relaxed(~0, &g->clr_falling);
	writel_relaxed(~0, &g->clr_rising);

	/*
	* Each chip handles 32 gpios, and each irq bank consists of 16
	* gpio irqs. Pass the irq bank's corresponding controller to
	* the chained irq handler.
	*/
	irq_set_chained_handler_and_data(bank_irq, gpio_irq_handler,
	&chips[gpio / 32]);

	binten \|= BIT(bank);
	}

	done:
	/*
	* BINTEN -- per-bank interrupt enable. genirq would also let these
	* bits be set/cleared dynamically.
	*/
	writel_relaxed(binten, gpio_base + BINTEN);

	return 0;
	}

	#if IS_ENABLED(CONFIG_OF)
	static const struct of_device_id davinci_gpio_ids[] = {
	{ .compatible = "ti,keystone-gpio", keystone_gpio_get_irq_chip},
	{ .compatible = "ti,dm6441-gpio", davinci_gpio_get_irq_chip},
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(of, davinci_gpio_ids);
	#endif

	static struct platform_driver davinci_gpio_driver = {
	.probe = davinci_gpio_probe,
	.driver = {
	.name = "davinci_gpio",
	.of_match_table = of_match_ptr(davinci_gpio_ids),
	},
	};

	/**
	* GPIO driver registration needs to be done before machine_init functions
	* access GPIO. Hence davinci_gpio_drv_reg() is a postcore_initcall.
	*/
	static int __init davinci_gpio_drv_reg(void)
	{
	return platform_driver_register(&davinci_gpio_driver);
	}
	postcore_initcall(davinci_gpio_drv_reg);