drm/i915/bxt: add support for HPD long/short pulse detection on HPD_PORT_A pin

This is a requirement for enabling display port HPD support on the port
A HPD pin. This support is to be added by follow-up patches.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NSonika Jindal <sonika.jindal@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -1227,6 +1227,22 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_i915_private *dev_priv,
 	return ret;
 }
 
+static bool bxt_port_hotplug_long_detect(enum port port, u32 val)
+{
+	switch (port) {
+	case PORT_A:
+		return val & BXT_PORTA_HOTPLUG_LONG_DETECT;
+	case PORT_B:
+		return val & PORTB_HOTPLUG_LONG_DETECT;
+	case PORT_C:
+		return val & PORTC_HOTPLUG_LONG_DETECT;
+	case PORT_D:
+		return val & PORTD_HOTPLUG_LONG_DETECT;
+	default:
+		return false;
+	}
+}
+
 static bool pch_port_hotplug_long_detect(enum port port, u32 val)
 {
 	switch (port) {
@@ -1964,7 +1980,7 @@ static void bxt_hpd_handler(struct drm_device *dev, uint32_t iir_status)
 	I915_WRITE(BXT_HOTPLUG_CTL, hp_control);
 
 	intel_get_hpd_pins(&pin_mask, &long_mask, hp_trigger, hp_control,
-			   hpd_bxt, pch_port_hotplug_long_detect);
+			   hpd_bxt, bxt_port_hotplug_long_detect);
 	intel_hpd_irq_handler(dev, pin_mask, long_mask);
 }
 

drivers/gpu/drm/i915/i915_reg.h

@@ -5985,6 +5985,11 @@ enum skl_disp_power_wells {
 
 /* digital port hotplug */
 #define PCH_PORT_HOTPLUG        0xc4030		/* SHOTPLUG_CTL */
+#define BXT_PORTA_HOTPLUG_ENABLE	(1 << 28)
+#define BXT_PORTA_HOTPLUG_STATUS_MASK	(0x3 << 24)
+#define  BXT_PORTA_HOTPLUG_NO_DETECT	(0 << 24)
+#define  BXT_PORTA_HOTPLUG_SHORT_DETECT	(1 << 24)
+#define  BXT_PORTA_HOTPLUG_LONG_DETECT	(2 << 24)
 #define PORTD_HOTPLUG_ENABLE            (1 << 20)
 #define PORTD_PULSE_DURATION_2ms        (0)
 #define PORTD_PULSE_DURATION_4_5ms      (1 << 18)