[PATCH 2/3 v2] GPIO: gpio-dwapb: Support Debounce

[Weike Chen <alvin.chen@intel.com>]

This patch enables 'debounce' for the designware GPIO, and
it is based on Josef Ahmad's previous work.

Reviewed-by: Hock Leong Kweh <hock.leong.kweh@intel.com>
Reviewed-by: Shevchenko, Andriy <andriy.shevchenko@intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
---
 drivers/gpio/gpio-dwapb.c |   62 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 52 insertions(+), 10 deletions(-)

diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index f2264a2..6db7501 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -36,6 +36,7 @@
 #define GPIO_INTTYPE_LEVEL	0x38
 #define GPIO_INT_POLARITY	0x3c
 #define GPIO_INTSTATUS		0x40
+#define GPIO_PORTA_DEBOUNCE	0x48
 #define GPIO_PORTA_EOI		0x4c
 #define GPIO_EXT_PORTA		0x50
 #define GPIO_EXT_PORTB		0x54
@@ -63,6 +64,23 @@ struct dwapb_gpio {
 	struct irq_domain	*domain;
 };
 
+static inline u32 dwapb_read(struct dwapb_gpio *gpio, unsigned int offset)
+{
+	struct bgpio_chip *bgc	= &gpio->ports[0].bgc;
+	void __iomem *reg_base	= gpio->regs;
+
+	return bgc->read_reg(reg_base + offset);
+}
+
+static inline void dwapb_write(struct dwapb_gpio *gpio, unsigned int offset,
+			       u32 val)
+{
+	struct bgpio_chip *bgc	= &gpio->ports[0].bgc;
+	void __iomem *reg_base	= gpio->regs;
+
+	bgc->write_reg(reg_base + offset, val);
+}
+
 static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
 {
 	struct bgpio_chip *bgc = to_bgpio_chip(gc);
@@ -75,14 +93,14 @@ static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
 
 static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
 {
-	u32 v = readl(gpio->regs + GPIO_INT_POLARITY);
+	u32 v = dwapb_read(gpio, GPIO_INT_POLARITY);
 
 	if (gpio_get_value(gpio->ports[0].bgc.gc.base + offs))
 		v &= ~BIT(offs);
 	else
 		v |= BIT(offs);
 
-	writel(v, gpio->regs + GPIO_INT_POLARITY);
+	dwapb_write(gpio, GPIO_INT_POLARITY, v);
 }
 
 static u32 _dwapb_irq_handler(struct dwapb_gpio *gpio)
@@ -125,9 +143,9 @@ static void dwapb_irq_enable(struct irq_data *d)
 	u32 val;
 
 	spin_lock_irqsave(&bgc->lock, flags);
-	val = readl(gpio->regs + GPIO_INTEN);
+	val = dwapb_read(gpio, GPIO_INTEN);
 	val |= BIT(d->hwirq);
-	writel(val, gpio->regs + GPIO_INTEN);
+	dwapb_write(gpio, GPIO_INTEN, val);
 	spin_unlock_irqrestore(&bgc->lock, flags);
 }
 
@@ -140,9 +158,9 @@ static void dwapb_irq_disable(struct irq_data *d)
 	u32 val;
 
 	spin_lock_irqsave(&bgc->lock, flags);
-	val = readl(gpio->regs + GPIO_INTEN);
+	val = dwapb_read(gpio, GPIO_INTEN);
 	val &= ~BIT(d->hwirq);
-	writel(val, gpio->regs + GPIO_INTEN);
+	dwapb_write(gpio, GPIO_INTEN, val);
 	spin_unlock_irqrestore(&bgc->lock, flags);
 }
 
@@ -182,8 +200,8 @@ static int dwapb_irq_set_type(struct irq_data *d, u32 type)
 		return -EINVAL;
 
 	spin_lock_irqsave(&bgc->lock, flags);
-	level = readl(gpio->regs + GPIO_INTTYPE_LEVEL);
-	polarity = readl(gpio->regs + GPIO_INT_POLARITY);
+	level = dwapb_read(gpio, GPIO_INTTYPE_LEVEL);
+	polarity = dwapb_read(gpio, GPIO_INT_POLARITY);
 
 	switch (type) {
 	case IRQ_TYPE_EDGE_BOTH:
@@ -210,8 +228,31 @@ static int dwapb_irq_set_type(struct irq_data *d, u32 type)
 
 	irq_setup_alt_chip(d, type);
 
-	writel(level, gpio->regs + GPIO_INTTYPE_LEVEL);
-	writel(polarity, gpio->regs + GPIO_INT_POLARITY);
+	dwapb_write(gpio, GPIO_INTTYPE_LEVEL, level);
+	dwapb_write(gpio, GPIO_INT_POLARITY, polarity);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+
+	return 0;
+}
+
+static int dwapb_gpio_set_debounce(struct gpio_chip *gc,
+				   unsigned offset, unsigned debounce)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+	struct dwapb_gpio_port *port =
+			container_of(bgc, struct dwapb_gpio_port, bgc);
+	struct dwapb_gpio *gpio = port->gpio;
+	unsigned long flags, val_deb;
+	unsigned long mask = bgc->pin2mask(bgc, offset);
+
+	spin_lock_irqsave(&bgc->lock, flags);
+
+	val_deb = dwapb_read(gpio, GPIO_PORTA_DEBOUNCE);
+	if (debounce)
+		dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, mask | val_deb);
+	else
+		dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, ~mask & val_deb);
+
 	spin_unlock_irqrestore(&bgc->lock, flags);
 
 	return 0;
@@ -354,6 +395,7 @@ static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
 #endif
 	port->bgc.gc.ngpio = pp->ngpio;
 	port->bgc.gc.base = pp->gpio_base;
+	port->bgc.gc.set_debounce = dwapb_gpio_set_debounce;
 
 	if (pp->irq)
 		dwapb_configure_irqs(gpio, port, pp);
-- 
1.7.9.5