gpio: mm-lantiq: Drop legacy-of-mm-gpiochip.h header from GPIO driver

Remove legacy-of-mm-gpiochip.h header file. The above mentioned
file provides an OF API that's deprecated. There is no agnostic
alternatives to it and we have to open code the logic which was
hidden behind of_mm_gpiochip_add_data(). Note, most of the GPIO
drivers are using their own labeling schemas and resource retrieval
that only a few may gain of the code deduplication, so whenever
alternative is appear we can move drivers again to use that one.

[Text copied from commit 34064c8267a6 ("powerpc/8xx: Drop
legacy-of-mm-gpiochip.h header")]

Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/Kconfig

···
 config GPIO_MM_LANTIQ
 	bool "Lantiq Memory mapped GPIOs"
 	depends on LANTIQ && SOC_XWAY
-	select OF_GPIO_MM_GPIOCHIP
 	help
 	  This enables support for memory mapped GPIOs on the External Bus Unit
 	  (EBU) found on Lantiq SoCs. The GPIOs are output only as they are

drivers/gpio/gpio-mm-lantiq.c

···
 #include <linux/platform_device.h>
 #include <linux/mutex.h>
 #include <linux/gpio/driver.h>
-#include <linux/gpio/legacy-of-mm-gpiochip.h>
 #include <linux/of.h>
 #include <linux/io.h>
 #include <linux/slab.h>
···
 #define LTQ_EBU_WP	0x80000000	/* write protect bit */
 
 struct ltq_mm {
-	struct of_mm_gpio_chip mmchip;
+	struct gpio_chip gc;
+	void __iomem *regs;
 	u16 shadow;	/* shadow the latches state */
 };
 
···
 
 	spin_lock_irqsave(&ebu_lock, flags);
 	ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1);
-	__raw_writew(chip->shadow, chip->mmchip.regs);
+	__raw_writew(chip->shadow, chip->regs);
 	ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);
 	spin_unlock_irqrestore(&ebu_lock, flags);
 }
···
  * ltq_mm_save_regs() - Set initial values of GPIO pins
  * @mm_gc: pointer to memory mapped GPIO chip structure
  */
-static void ltq_mm_save_regs(struct of_mm_gpio_chip *mm_gc)
+static void ltq_mm_save_regs(struct ltq_mm *chip)
 {
-	struct ltq_mm *chip =
-		container_of(mm_gc, struct ltq_mm, mmchip);
-
 	/* tell the ebu controller which memory address we will be using */
-	ltq_ebu_w32(CPHYSADDR(chip->mmchip.regs) | 0x1, LTQ_EBU_ADDRSEL1);
+	ltq_ebu_w32(CPHYSADDR((__force void *)chip->regs) | 0x1, LTQ_EBU_ADDRSEL1);
 
 	ltq_mm_apply(chip);
 }
 
 static int ltq_mm_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct gpio_chip *gc;
 	struct ltq_mm *chip;
 	u32 shadow;
 
···
 	if (!chip)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, chip);
+	gc = &chip->gc;
 
-	chip->mmchip.gc.ngpio = 16;
-	chip->mmchip.gc.direction_output = ltq_mm_dir_out;
-	chip->mmchip.gc.set = ltq_mm_set;
-	chip->mmchip.save_regs = ltq_mm_save_regs;
+	gc->base = -1;
+	gc->ngpio = 16;
+	gc->direction_output = ltq_mm_dir_out;
+	gc->set = ltq_mm_set;
+	gc->parent = dev;
+	gc->owner = THIS_MODULE;
+	gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pOF", np);
+	if (!gc->label)
+		return -ENOMEM;
+
+	chip->regs = devm_of_iomap(dev, np, 0, NULL);
+	if (IS_ERR(chip->regs))
+		return PTR_ERR(chip->regs);
+
+	ltq_mm_save_regs(chip);
 
 	/* store the shadow value if one was passed by the devicetree */
 	if (!of_property_read_u32(pdev->dev.of_node, "lantiq,shadow", &shadow))
 		chip->shadow = shadow;
 
-	return of_mm_gpiochip_add_data(pdev->dev.of_node, &chip->mmchip, chip);
-}
-
-static void ltq_mm_remove(struct platform_device *pdev)
-{
-	struct ltq_mm *chip = platform_get_drvdata(pdev);
-
-	of_mm_gpiochip_remove(&chip->mmchip);
+	return devm_gpiochip_add_data(dev, gc, chip);
 }
 
 static const struct of_device_id ltq_mm_match[] = {
···
 
 static struct platform_driver ltq_mm_driver = {
 	.probe = ltq_mm_probe,
-	.remove = ltq_mm_remove,
 	.driver = {
 		.name = "gpio-mm-ltq",
 		.of_match_table = ltq_mm_match,