powerpc: simple-gpio: use gpiochip data pointer

This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Cc: Anton Vorontsov <[e-mail]>
Cc: Anatolij Gustschin <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

arch/powerpc/sysdev/simple_gpio.c

···
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
-#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/slab.h>
 #include <asm/prom.h>
 #include "simple_gpio.h"
···
 	/* shadowed data register to clear/set bits safely */
 	u8 data;
 };
-
-static struct u8_gpio_chip *to_u8_gpio_chip(struct of_mm_gpio_chip *mm_gc)
-{
-	return container_of(mm_gc, struct u8_gpio_chip, mm_gc);
-}
 
 static u8 u8_pin2mask(unsigned int pin)
 {
···
 static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
-	struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc);
+	struct u8_gpio_chip *u8_gc = gpiochip_get_data(gc);
 	unsigned long flags;
 
 	spin_lock_irqsave(&u8_gc->lock, flags);
···
 
 static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 {
-	struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc);
+	struct u8_gpio_chip *u8_gc = gpiochip_get_data(&mm_gc->gc);
 
 	u8_gc->data = in_8(mm_gc->regs);
 }
···
 	gc->get = u8_gpio_get;
 	gc->set = u8_gpio_set;
 
-	ret = of_mm_gpiochip_add(np, mm_gc);
+	ret = of_mm_gpiochip_add_data(np, mm_gc, u8_gc);
 	if (ret)
 		goto err;
 	return 0;