staging: mt7621-gpio: avoid custom irq_domain for gpio

Instead of create a custom irq_domain for this chip, use
'gpiochip_set_chained_irqchip' from GPIOLIB_IRQCHIP. It
is ok to call this function several times. We have to
manually mark the line with 'IRQF_SHARED' and then loop
over the three banks until you find a hit. There were
some problems with removing an irqchip like that but this
driver is a bool so it might work just fine. After this
changes the functions 'mediatek_gpio_to_irq' is not needed
anymore and also the 'gpio_irq_domain' field from the state
container. Instead of use the custom irq domain in the irq
handler use the associated domain from the gpio_chip in
'irq_find_mapping' function. Function 'mediatek_gpio_bank_probe'
has been moved a it to the botton to have all the irq related
functions together and avoid some forward declarations to resolve
some symbols along the code.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-gpio/Kconfig

@@ -2,6 +2,7 @@ config GPIO_MT7621
 	bool "Mediatek GPIO Support"
 	depends on SOC_MT7620 || SOC_MT7621 || COMPILE_TEST
 	select GPIO_GENERIC
+	select GPIOLIB_IRQCHIP
 	select ARCH_REQUIRE_GPIOLIB
 	help
 	  Say yes here to support the Mediatek SoC GPIO device

drivers/staging/mt7621-gpio/gpio-mt7621.c

@@ -8,7 +8,6 @@
 #include <linux/gpio/driver.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
-#include <linux/irqdomain.h>
 #include <linux/module.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
@@ -58,14 +57,12 @@ struct mtk_gc {
  * @dev: device instance
  * @gpio_membase: memory base address
  * @gpio_irq: irq number from the device tree
- * @gpio_irq_domain: irq domain for this chip
  * @gc_map: array of the gpio chips
  */
 struct mtk_data {
 	struct device *dev;
 	void __iomem *gpio_membase;
 	int gpio_irq;
-	struct irq_domain *gpio_irq_domain;
 	struct mtk_gc gc_map[MTK_BANK_CNT];
 };
 
@@ -95,98 +92,36 @@ mtk_gpio_r32(struct mtk_gc *rg, u32 offset)
 	return gc->read_reg(gpio_data->gpio_membase + offset);
 }
 
-static int
-mediatek_gpio_to_irq(struct gpio_chip *chip, unsigned int pin)
-{
-	struct mtk_data *gpio_data = gpiochip_get_data(chip);
-	struct mtk_gc *rg = to_mediatek_gpio(chip);
-
-	return irq_create_mapping(gpio_data->gpio_irq_domain,
-				  pin + (rg->bank * MTK_BANK_WIDTH));
-}
-
-static int
-mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
-{
-	struct mtk_data *gpio = dev_get_drvdata(&pdev->dev);
-	const __be32 *id = of_get_property(bank, "reg", NULL);
-	struct mtk_gc *rg;
-	void __iomem *dat, *set, *ctrl, *diro;
-	int ret;
-
-	if (!id || be32_to_cpu(*id) >= MTK_BANK_CNT)
-		return -EINVAL;
-
-	rg = &gpio->gc_map[be32_to_cpu(*id)];
-	memset(rg, 0, sizeof(*rg));
-
-	spin_lock_init(&rg->lock);
-	rg->chip.of_node = bank;
-	rg->bank = be32_to_cpu(*id);
-
-	dat = gpio->gpio_membase + GPIO_REG_DATA + (rg->bank * GPIO_BANK_WIDE);
-	set = gpio->gpio_membase + GPIO_REG_DSET + (rg->bank * GPIO_BANK_WIDE);
-	ctrl = gpio->gpio_membase + GPIO_REG_DCLR + (rg->bank * GPIO_BANK_WIDE);
-	diro = gpio->gpio_membase + GPIO_REG_CTRL + (rg->bank * GPIO_BANK_WIDE);
-
-	ret = bgpio_init(&rg->chip, &pdev->dev, 4,
-			 dat, set, ctrl, diro, NULL, 0);
-	if (ret) {
-		dev_err(&pdev->dev, "bgpio_init() failed\n");
-		return ret;
-	}
-
-	if (gpio->gpio_irq_domain)
-		rg->chip.to_irq = mediatek_gpio_to_irq;
-
-	ret = devm_gpiochip_add_data(&pdev->dev, &rg->chip, gpio);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "Could not register gpio %d, ret=%d\n",
-			rg->chip.ngpio, ret);
-		return ret;
-	}
-
-	/* set polarity to low for all gpios */
-	mtk_gpio_w32(rg, GPIO_REG_POL, 0);
-
-	dev_info(&pdev->dev, "registering %d gpios\n", rg->chip.ngpio);
-
-	return 0;
-}
-
-static void
-mediatek_gpio_irq_handler(struct irq_desc *desc)
+static irqreturn_t
+mediatek_gpio_irq_handler(int irq, void *data)
 {
-	struct mtk_data *gpio_data = irq_desc_get_handler_data(desc);
-	int i;
-
-	for (i = 0; i < MTK_BANK_CNT; i++) {
-		struct mtk_gc *rg = &gpio_data->gc_map[i];
-		unsigned long pending;
-		int bit;
-
-		if (!rg)
-			continue;
+	struct gpio_chip *gc = data;
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
+	irqreturn_t ret = IRQ_NONE;
+	unsigned long pending;
+	int bit;
 
-		pending = mtk_gpio_r32(rg, GPIO_REG_STAT);
+	pending = mtk_gpio_r32(rg, GPIO_REG_STAT);
 
+	if (pending) {
 		for_each_set_bit(bit, &pending, MTK_BANK_WIDTH) {
-			u32 map = irq_find_mapping(gpio_data->gpio_irq_domain,
-						   (MTK_BANK_WIDTH * i) + bit);
+			u32 map = irq_find_mapping(gc->irq.domain, bit);
 
 			generic_handle_irq(map);
 			mtk_gpio_w32(rg, GPIO_REG_STAT, BIT(bit));
+			ret |= IRQ_HANDLED;
 		}
 	}
+
+	return ret;
 }
 
 static void
 mediatek_gpio_irq_unmask(struct irq_data *d)
 {
-	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
 	int pin = d->hwirq;
-	int bank = pin / MTK_BANK_WIDTH;
-	struct mtk_gc *rg = &gpio_data->gc_map[bank];
 	unsigned long flags;
 	u32 rise, fall, high, low;
 
@@ -208,10 +143,9 @@ mediatek_gpio_irq_unmask(struct irq_data *d)
 static void
 mediatek_gpio_irq_mask(struct irq_data *d)
 {
-	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
 	int pin = d->hwirq;
-	int bank = pin / MTK_BANK_WIDTH;
-	struct mtk_gc *rg = &gpio_data->gc_map[bank];
 	unsigned long flags;
 	u32 rise, fall, high, low;
 
@@ -233,10 +167,9 @@ mediatek_gpio_irq_mask(struct irq_data *d)
 static int
 mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
 {
-	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mtk_gc *rg = to_mediatek_gpio(gc);
 	int pin = d->hwirq;
-	int bank = pin / MTK_BANK_WIDTH;
-	struct mtk_gc *rg = &gpio_data->gc_map[bank];
 	u32 mask = PIN_MASK(pin);
 
 	if (!rg)
@@ -277,65 +210,84 @@ mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
 	return 0;
 }
 
-static int mediatek_irq_reqres(struct irq_data *d)
-{
-	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
-	int bank = irqd_to_hwirq(d) / MTK_BANK_WIDTH;
-	struct mtk_gc *rg = &gpio_data->gc_map[bank];
-	struct gpio_chip *gc = &rg->chip;
-	int ret;
-
-	ret = gpiochip_lock_as_irq(gc, irqd_to_hwirq(d));
-	if (ret) {
-		dev_err(gpio_data->dev, "unable to lock HW IRQ %lu for IRQ\n",
-			irqd_to_hwirq(d));
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static void mediatek_irq_relres(struct irq_data *d)
-{
-	struct mtk_data *gpio_data = irq_data_get_irq_chip_data(d);
-	int bank = irqd_to_hwirq(d) / MTK_BANK_WIDTH;
-	struct mtk_gc *rg = &gpio_data->gc_map[bank];
-	struct gpio_chip *gc = &rg->chip;
-
-	gpiochip_unlock_as_irq(gc, irqd_to_hwirq(d));
-}
-
 static struct irq_chip mediatek_gpio_irq_chip = {
 	.name			= "GPIO",
 	.irq_unmask		= mediatek_gpio_irq_unmask,
 	.irq_mask		= mediatek_gpio_irq_mask,
 	.irq_mask_ack		= mediatek_gpio_irq_mask,
 	.irq_set_type		= mediatek_gpio_irq_type,
-	.irq_request_resources	= mediatek_irq_reqres,
-	.irq_release_resources	= mediatek_irq_relres,
 };
 
 static int
-mediatek_gpio_gpio_map(struct irq_domain *d, unsigned int irq,
-		       irq_hw_number_t hw)
+mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
 {
+	struct mtk_data *gpio = dev_get_drvdata(&pdev->dev);
+	const __be32 *id = of_get_property(bank, "reg", NULL);
+	struct mtk_gc *rg;
+	void __iomem *dat, *set, *ctrl, *diro;
 	int ret;
 
-	ret = irq_set_chip_data(irq, d->host_data);
-	if (ret < 0)
+	if (!id || be32_to_cpu(*id) >= MTK_BANK_CNT)
+		return -EINVAL;
+
+	rg = &gpio->gc_map[be32_to_cpu(*id)];
+	memset(rg, 0, sizeof(*rg));
+
+	spin_lock_init(&rg->lock);
+	rg->chip.of_node = bank;
+	rg->bank = be32_to_cpu(*id);
+
+	dat = gpio->gpio_membase + GPIO_REG_DATA + (rg->bank * GPIO_BANK_WIDE);
+	set = gpio->gpio_membase + GPIO_REG_DSET + (rg->bank * GPIO_BANK_WIDE);
+	ctrl = gpio->gpio_membase + GPIO_REG_DCLR + (rg->bank * GPIO_BANK_WIDE);
+	diro = gpio->gpio_membase + GPIO_REG_CTRL + (rg->bank * GPIO_BANK_WIDE);
+
+	ret = bgpio_init(&rg->chip, &pdev->dev, 4,
+			 dat, set, ctrl, diro, NULL, 0);
+	if (ret) {
+		dev_err(&pdev->dev, "bgpio_init() failed\n");
+		return ret;
+	}
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &rg->chip, gpio);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpio %d, ret=%d\n",
+			rg->chip.ngpio, ret);
+		return ret;
+	}
+
+	/*
+	 * Manually request the irq here instead of passing a flow-handler
+	 * to gpiochip_set_chained_irqchip, because the irq is shared.
+	 */
+	ret = devm_request_irq(&pdev->dev, gpio->gpio_irq,
+			       mediatek_gpio_irq_handler, IRQF_SHARED,
+			       "mt7621", &rg->chip);
+
+	if (ret) {
+		dev_err(&pdev->dev, "Error requesting IRQ %d: %d\n",
+			gpio->gpio_irq, ret);
 		return ret;
-	irq_set_chip_and_handler(irq, &mediatek_gpio_irq_chip,
-				 handle_level_irq);
-	irq_set_handler_data(irq, d);
+	}
+
+	ret = gpiochip_irqchip_add(&rg->chip, &mediatek_gpio_irq_chip,
+				   0, handle_simple_irq, IRQ_TYPE_NONE);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add gpiochip_irqchip\n");
+		return ret;
+	}
+
+	gpiochip_set_chained_irqchip(&rg->chip, &mediatek_gpio_irq_chip,
+				     gpio->gpio_irq, NULL);
+
+	/* set polarity to low for all gpios */
+	mtk_gpio_w32(rg, GPIO_REG_POL, 0);
+
+	dev_info(&pdev->dev, "registering %d gpios\n", rg->chip.ngpio);
 
 	return 0;
 }
 
-static const struct irq_domain_ops irq_domain_ops = {
-	.xlate = irq_domain_xlate_twocell,
-	.map = mediatek_gpio_gpio_map,
-};
-
 static int
 mediatek_gpio_probe(struct platform_device *pdev)
 {
@@ -352,14 +304,6 @@ mediatek_gpio_probe(struct platform_device *pdev)
 		return PTR_ERR(gpio_data->gpio_membase);
 
 	gpio_data->gpio_irq = irq_of_parse_and_map(np, 0);
-	if (gpio_data->gpio_irq) {
-		gpio_data->gpio_irq_domain = irq_domain_add_linear(np,
-			MTK_BANK_CNT * MTK_BANK_WIDTH,
-			&irq_domain_ops, gpio_data);
-		if (!gpio_data->gpio_irq_domain)
-			dev_err(&pdev->dev, "irq_domain_add_linear failed\n");
-	}
-
 	gpio_data->dev = &pdev->dev;
 	platform_set_drvdata(pdev, gpio_data);
 
@@ -367,11 +311,6 @@ mediatek_gpio_probe(struct platform_device *pdev)
 		if (of_device_is_compatible(bank, "mediatek,mt7621-gpio-bank"))
 			mediatek_gpio_bank_probe(pdev, bank);
 
-	if (gpio_data->gpio_irq_domain)
-		irq_set_chained_handler_and_data(gpio_data->gpio_irq,
-						 mediatek_gpio_irq_handler,
-						 gpio_data);
-
 	return 0;
 }