staging: mt7621-gpio: make use 'bgpio_init' from GPIO_GENERIC

Gpio complexity is just masking the fact that offset is always
0..n and writes to bits 0..n of some memory address. Because
of this whole thing can just me converted to use GPIO_GENERIC
and avoid duplications of a lot of driver custom functions.
So use bgpio_init instead of custom code adding GPIO_GENERIC
dependency to the Kconfig file. Also to make easier using
bgpio_init function offset for each gpio bank, enumeration
where register were defined has been replaced in favour of
some macros which handle each gpio offset taking into account
the bank where are located. Because of this change write and
read functions which are being used for remaining irq handling
stuff have been updated also as well as its dependencies along
the code.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-gpio/Kconfig

 config GPIO_MT7621
 	bool "Mediatek GPIO Support"
 	depends on SOC_MT7620 || SOC_MT7621
+	select GPIO_GENERIC
 	select ARCH_REQUIRE_GPIOLIB
 	help
 	  Say yes here to support the Mediatek SoC GPIO device

drivers/staging/mt7621-gpio/gpio-mt7621.c

@@ -19,19 +19,18 @@
 #define MTK_BANK_WIDTH		32
 #define PIN_MASK(nr)		(1UL << ((nr % MTK_BANK_WIDTH)))
 
-enum mediatek_gpio_reg {
-	GPIO_REG_CTRL = 0,
-	GPIO_REG_POL,
-	GPIO_REG_DATA,
-	GPIO_REG_DSET,
-	GPIO_REG_DCLR,
-	GPIO_REG_REDGE,
-	GPIO_REG_FEDGE,
-	GPIO_REG_HLVL,
-	GPIO_REG_LLVL,
-	GPIO_REG_STAT,
-	GPIO_REG_EDGE,
-};
+#define GPIO_BANK_WIDE	0x04
+#define GPIO_REG_CTRL	0x00
+#define GPIO_REG_POL	0x10
+#define GPIO_REG_DATA	0x20
+#define GPIO_REG_DSET	0x30
+#define GPIO_REG_DCLR	0x40
+#define GPIO_REG_REDGE	0x50
+#define GPIO_REG_FEDGE	0x60
+#define GPIO_REG_HLVL	0x70
+#define GPIO_REG_LLVL	0x80
+#define GPIO_REG_STAT	0x90
+#define GPIO_REG_EDGE	0xA0
 
 struct mtk_gc {
 	struct gpio_chip chip;
@@ -55,80 +54,23 @@ to_mediatek_gpio(struct gpio_chip *chip)
 }
 
 static inline void
-mtk_gpio_w32(struct mtk_gc *rg, u8 reg, u32 val)
+mtk_gpio_w32(struct mtk_gc *rg, u32 offset, u32 val)
 {
-	struct mtk_data *gpio_data = gpiochip_get_data(&rg->chip);
-	u32 offset = (reg * 0x10) + (rg->bank * 0x4);
+	struct gpio_chip *gc = &rg->chip;
+	struct mtk_data *gpio_data = gpiochip_get_data(gc);
 
-	iowrite32(val, gpio_data->gpio_membase + offset);
+	offset = (rg->bank * GPIO_BANK_WIDE) + offset;
+	gc->write_reg(gpio_data->gpio_membase + offset, val);
 }
 
 static inline u32
-mtk_gpio_r32(struct mtk_gc *rg, u8 reg)
-{
-	struct mtk_data *gpio_data = gpiochip_get_data(&rg->chip);
-	u32 offset = (reg * 0x10) + (rg->bank * 0x4);
-
-	return ioread32(gpio_data->gpio_membase + offset);
-}
-
-static void
-mediatek_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
-{
-	struct mtk_gc *rg = to_mediatek_gpio(chip);
-
-	mtk_gpio_w32(rg, (value) ? GPIO_REG_DSET : GPIO_REG_DCLR, BIT(offset));
-}
-
-static int
-mediatek_gpio_get(struct gpio_chip *chip, unsigned int offset)
-{
-	struct mtk_gc *rg = to_mediatek_gpio(chip);
-
-	return !!(mtk_gpio_r32(rg, GPIO_REG_DATA) & BIT(offset));
-}
-
-static int
-mediatek_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
-{
-	struct mtk_gc *rg = to_mediatek_gpio(chip);
-	unsigned long flags;
-	u32 t;
-
-	spin_lock_irqsave(&rg->lock, flags);
-	t = mtk_gpio_r32(rg, GPIO_REG_CTRL);
-	t &= ~BIT(offset);
-	mtk_gpio_w32(rg, GPIO_REG_CTRL, t);
-	spin_unlock_irqrestore(&rg->lock, flags);
-
-	return 0;
-}
-
-static int
-mediatek_gpio_direction_output(struct gpio_chip *chip,
-					unsigned int offset, int value)
+mtk_gpio_r32(struct mtk_gc *rg, u32 offset)
 {
-	struct mtk_gc *rg = to_mediatek_gpio(chip);
-	unsigned long flags;
-	u32 t;
+	struct gpio_chip *gc = &rg->chip;
+	struct mtk_data *gpio_data = gpiochip_get_data(gc);
 
-	spin_lock_irqsave(&rg->lock, flags);
-	t = mtk_gpio_r32(rg, GPIO_REG_CTRL);
-	t |= BIT(offset);
-	mtk_gpio_w32(rg, GPIO_REG_CTRL, t);
-	mediatek_gpio_set(chip, offset, value);
-	spin_unlock_irqrestore(&rg->lock, flags);
-
-	return 0;
-}
-
-static int
-mediatek_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
-{
-	struct mtk_gc *rg = to_mediatek_gpio(chip);
-	u32 t = mtk_gpio_r32(rg, GPIO_REG_CTRL);
-
-	return (t & BIT(offset)) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
+	offset = (rg->bank * GPIO_BANK_WIDE) + offset;
+	return gc->read_reg(gpio_data->gpio_membase + offset);
 }
 
 static int
@@ -144,34 +86,38 @@ mediatek_gpio_to_irq(struct gpio_chip *chip, unsigned int pin)
 static int
 mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
 {
-	struct mtk_data *gpio_data = dev_get_drvdata(&pdev->dev);
+	struct mtk_data *gpio = dev_get_drvdata(&pdev->dev);
 	const __be32 *id = of_get_property(bank, "reg", NULL);
 	struct mtk_gc *rg;
+	void __iomem *dat, *set, *ctrl, *diro;
 	int ret;
 
 	if (!id || be32_to_cpu(*id) >= MTK_BANK_CNT)
 		return -EINVAL;
 
-	rg = &gpio_data->gc_map[be32_to_cpu(*id)];
+	rg = &gpio->gc_map[be32_to_cpu(*id)];
 	memset(rg, 0, sizeof(*rg));
 
 	spin_lock_init(&rg->lock);
-
-	rg->chip.parent = &pdev->dev;
-	rg->chip.label = dev_name(&pdev->dev);
 	rg->chip.of_node = bank;
-	rg->chip.base = MTK_BANK_WIDTH * be32_to_cpu(*id);
-	rg->chip.ngpio = MTK_BANK_WIDTH;
-	rg->chip.direction_input = mediatek_gpio_direction_input;
-	rg->chip.direction_output = mediatek_gpio_direction_output;
-	rg->chip.get_direction = mediatek_gpio_get_direction;
-	rg->chip.get = mediatek_gpio_get;
-	rg->chip.set = mediatek_gpio_set;
-	if (gpio_data->gpio_irq_domain)
-		rg->chip.to_irq = mediatek_gpio_to_irq;
 	rg->bank = be32_to_cpu(*id);
 
-	ret = devm_gpiochip_add_data(&pdev->dev, &rg->chip, gpio_data);
+	dat = gpio->gpio_membase + GPIO_REG_DATA + (rg->bank * GPIO_BANK_WIDE);
+	set = gpio->gpio_membase + GPIO_REG_DSET + (rg->bank * GPIO_BANK_WIDE);
+	ctrl = gpio->gpio_membase + GPIO_REG_DCLR + (rg->bank * GPIO_BANK_WIDE);
+	diro = gpio->gpio_membase + GPIO_REG_CTRL + (rg->bank * GPIO_BANK_WIDE);
+
+	ret = bgpio_init(&rg->chip, &pdev->dev, 4,
+			 dat, set, ctrl, diro, NULL, 0);
+	if (ret) {
+		dev_err(&pdev->dev, "bgpio_init() failed\n");
+		return ret;
+	}
+
+	if (gpio->gpio_irq_domain)
+		rg->chip.to_irq = mediatek_gpio_to_irq;
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &rg->chip, gpio);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Could not register gpio %d, ret=%d\n",
 			rg->chip.ngpio, ret);