pinctrl: rockchip: Handle wakeup pins

The rockchip pinctrl driver was using irq_gc_set_wake() as its
implementation of irq_set_wake() but was totally ignoring everything
that irq_gc_set_wake() did (which is to upkeep gc->wake_active).

Let's fix that by setting gc->wake_active as GPIO_INTEN at suspend
time and restoring GPIO_INTEN at resume time.

NOTE a few quirks when thinking about this patch:
- Rockchip pinctrl hardware supports both "disable/enable" and
  "mask/unmask".  Right now we only use "disable/enable" and present
  those to Linux as "mask/unmask".  This should be OK because
  enable/disable is optional and Linux will implement it in terms of
  mask/unmask.  At the moment we always tell hardware all interrupts
  are unmasked (the boot default).
- At suspend time Linux tries to call "disable" on all interrupts and
  also enables wakeup on all wakeup interrupts.  One would think that
  since "disable" is implemented as "mask" when "disable" isn't
  provided and that since we were ignoring gc->wake_active that
  nothing would have woken us up.  That's not the case since Linux
  "optimizes" things and just leaves interrutps unmasked, assuming it
  could mask them later when they go off.  That meant that at suspend
  time all interrupts were actually being left enabled.

With this patch random non-wakeup interrupts no longer wake the system
up.  Wakeup interrupts still wake the system up.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-rockchip.c

@@ -89,6 +89,7 @@ struct rockchip_iomux {
  * @reg_pull: optional separate register for additional pull settings
  * @clk: clock of the gpio bank
  * @irq: interrupt of the gpio bank
+ * @saved_enables: Saved content of GPIO_INTEN at suspend time.
  * @pin_base: first pin number
  * @nr_pins: number of pins in this bank
  * @name: name of the bank
@@ -107,6 +108,7 @@ struct rockchip_pin_bank {
 	struct regmap			*regmap_pull;
 	struct clk			*clk;
 	int				irq;
+	u32				saved_enables;
 	u32				pin_base;
 	u8				nr_pins;
 	char				*name;
@@ -1543,6 +1545,23 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
 	return 0;
 }
 
+static void rockchip_irq_suspend(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct rockchip_pin_bank *bank = gc->private;
+
+	bank->saved_enables = irq_reg_readl(gc, GPIO_INTEN);
+	irq_reg_writel(gc, gc->wake_active, GPIO_INTEN);
+}
+
+static void rockchip_irq_resume(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct rockchip_pin_bank *bank = gc->private;
+
+	irq_reg_writel(gc, bank->saved_enables, GPIO_INTEN);
+}
+
 static int rockchip_interrupts_register(struct platform_device *pdev,
 						struct rockchip_pinctrl *info)
 {
@@ -1587,6 +1606,8 @@ static int rockchip_interrupts_register(struct platform_device *pdev,
 		gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
 		gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
 		gc->chip_types[0].chip.irq_set_wake = irq_gc_set_wake;
+		gc->chip_types[0].chip.irq_suspend = rockchip_irq_suspend;
+		gc->chip_types[0].chip.irq_resume = rockchip_irq_resume;
 		gc->chip_types[0].chip.irq_set_type = rockchip_irq_set_type;
 		gc->wake_enabled = IRQ_MSK(bank->nr_pins);