gpio: mmio: use new generic GPIO chip API

Convert the driver to using the new generic GPIO chip interfaces from
linux/gpio/generic.h.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250910-gpio-mmio-gpio-conv-part4-v2-14-f3d1a4c57124@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: Bartosz Golaszewski

drivers/gpio/gpio-mmio.c

@@ -57,6 +57,7 @@ o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
 #include <linux/types.h>
 
 #include <linux/gpio/driver.h>
+#include <linux/gpio/generic.h>
 
 #include "gpiolib.h"
 
@@ -737,6 +738,8 @@ MODULE_DEVICE_TABLE(of, bgpio_of_match);
 
 static int bgpio_pdev_probe(struct platform_device *pdev)
 {
+	struct gpio_generic_chip_config config;
+	struct gpio_generic_chip *gen_gc;
 	struct device *dev = &pdev->dev;
 	struct resource *r;
 	void __iomem *dat;
@@ -748,7 +751,6 @@ static int bgpio_pdev_probe(struct platform_device *pdev)
 	unsigned long flags = 0;
 	unsigned int base;
 	int err;
-	struct gpio_chip *gc;
 	const char *label;
 
 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
@@ -777,8 +779,8 @@ static int bgpio_pdev_probe(struct platform_device *pdev)
 	if (IS_ERR(dirin))
 		return PTR_ERR(dirin);
 
-	gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
-	if (!gc)
+	gen_gc = devm_kzalloc(&pdev->dev, sizeof(*gen_gc), GFP_KERNEL);
+	if (!gen_gc)
 		return -ENOMEM;
 
 	if (device_is_big_endian(dev))
@@ -787,25 +789,36 @@ static int bgpio_pdev_probe(struct platform_device *pdev)
 	if (device_property_read_bool(dev, "no-output"))
 		flags |= BGPIOF_NO_OUTPUT;
 
-	err = bgpio_init(gc, dev, sz, dat, set, clr, dirout, dirin, flags);
+	config = (struct gpio_generic_chip_config) {
+		.dev = dev,
+		.sz = sz,
+		.dat = dat,
+		.set = set,
+		.clr = clr,
+		.dirout = dirout,
+		.dirin = dirin,
+		.flags = flags,
+	};
+
+	err = gpio_generic_chip_init(gen_gc, &config);
 	if (err)
 		return err;
 
 	err = device_property_read_string(dev, "label", &label);
 	if (!err)
-		gc->label = label;
+		gen_gc->gc.label = label;
 
 	/*
 	 * This property *must not* be used in device-tree sources, it's only
 	 * meant to be passed to the driver from board files and MFD core.
 	 */
 	err = device_property_read_u32(dev, "gpio-mmio,base", &base);
 	if (!err && base <= INT_MAX)
-		gc->base = base;
+		gen_gc->gc.base = base;
 
-	platform_set_drvdata(pdev, gc);
+	platform_set_drvdata(pdev, &gen_gc->gc);
 
-	return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
+	return devm_gpiochip_add_data(&pdev->dev, &gen_gc->gc, NULL);
 }
 
 static const struct platform_device_id bgpio_id_table[] = {