gpio: generic: factor into gpio_chip struct

The separate struct bgpio_chip has been a pain to handle, both
by being confusingly similar in name to struct gpio_chip and
for being contained inside a struct so that struct gpio_chip
is contained in a struct contained in a struct, making several
steps of dereferencing necessary.

Make things simpler: include the fields directly into
<linux/gpio/driver.h>, #ifdef:ed for CONFIG_GENERIC_GPIO, and
get rid of the <linux/basic_mmio_gpio.h> altogether. Prefix
some of the member variables with bgpio_* and add proper
kerneldoc while we're at it.

Modify all users to handle the change and use a struct
gpio_chip directly. And while we're at it: replace all
container_of() dereferencing by gpiochip_get_data() and
registering the gpio_chip with gpiochip_add_data().

Cc: arm@kernel.org
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Rabin Vincent <rabin@rab.in>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-omap@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: bcm-kernel-feedback-list@broadcom.com
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-mxc.c

@@ -26,10 +26,11 @@
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/irqchip/chained_irq.h>
-#include <linux/gpio.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
-#include <linux/basic_mmio_gpio.h>
+#include <linux/gpio/driver.h>
+/* FIXME: for gpio_get_value() replace this with direct register read */
+#include <linux/gpio.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/module.h>
@@ -64,7 +65,7 @@ struct mxc_gpio_port {
 	int irq;
 	int irq_high;
 	struct irq_domain *domain;
-	struct bgpio_chip bgc;
+	struct gpio_chip gc;
 	u32 both_edges;
 };
 
@@ -172,7 +173,7 @@ static int gpio_set_irq_type(struct irq_data *d, u32 type)
 	struct mxc_gpio_port *port = gc->private;
 	u32 bit, val;
 	u32 gpio_idx = d->hwirq;
-	u32 gpio = port->bgc.gc.base + gpio_idx;
+	u32 gpio = port->gc.base + gpio_idx;
 	int edge;
 	void __iomem *reg = port->base;
 
@@ -398,9 +399,7 @@ static void mxc_gpio_get_hw(struct platform_device *pdev)
 
 static int mxc_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
 {
-	struct bgpio_chip *bgc = to_bgpio_chip(gc);
-	struct mxc_gpio_port *port =
-		container_of(bgc, struct mxc_gpio_port, bgc);
+	struct mxc_gpio_port *port = gpiochip_get_data(gc);
 
 	return irq_find_mapping(port->domain, offset);
 }
@@ -451,7 +450,7 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 							 port);
 	}
 
-	err = bgpio_init(&port->bgc, &pdev->dev, 4,
+	err = bgpio_init(&port->gc, &pdev->dev, 4,
 			 port->base + GPIO_PSR,
 			 port->base + GPIO_DR, NULL,
 			 port->base + GPIO_GDIR, NULL,
@@ -459,13 +458,13 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 	if (err)
 		goto out_bgio;
 
-	port->bgc.gc.to_irq = mxc_gpio_to_irq;
-	port->bgc.gc.base = (pdev->id < 0) ? of_alias_get_id(np, "gpio") * 32 :
+	port->gc.to_irq = mxc_gpio_to_irq;
+	port->gc.base = (pdev->id < 0) ? of_alias_get_id(np, "gpio") * 32 :
 					     pdev->id * 32;
 
-	err = gpiochip_add(&port->bgc.gc);
+	err = gpiochip_add_data(&port->gc, port);
 	if (err)
-		goto out_bgpio_remove;
+		goto out_bgio;
 
 	irq_base = irq_alloc_descs(-1, 0, 32, numa_node_id());
 	if (irq_base < 0) {
@@ -494,9 +493,7 @@ out_irqdomain_remove:
 out_irqdesc_free:
 	irq_free_descs(irq_base, 32);
 out_gpiochip_remove:
-	gpiochip_remove(&port->bgc.gc);
-out_bgpio_remove:
-	bgpio_remove(&port->bgc);
+	gpiochip_remove(&port->gc);
 out_bgio:
 	dev_info(&pdev->dev, "%s failed with errno %d\n", __func__, err);
 	return err;