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 <anton@enomsg.org>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/powerpc/sysdev/simple_gpio.c

@@ -19,7 +19,7 @@
 #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"
@@ -32,11 +32,6 @@ struct u8_gpio_chip {
 	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)
 {
 	return 1 << (8 - 1 - pin);
@@ -52,7 +47,7 @@ static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio)
 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);
@@ -80,7 +75,7 @@ static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 
 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);
 }
@@ -108,7 +103,7 @@ static int __init u8_simple_gpiochip_add(struct device_node *np)
 	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;