M3 Pro: panel off on DPMS, sleep with a dark external display

Documentation/devicetree/bindings/rtc/apple,smc-rtc.yaml

@@ -20,15 +20,36 @@ properties:
     const: apple,smc-rtc
 
   nvmem-cells:
+    minItems: 1
     items:
       - description:
           RTC offset. By default a 48bit value, specified in 32768 (2^15) Hz
           clock ticks. With apple,rtc-offset-seconds, a 64bit little-endian
           count of whole seconds.
+      - description:
+          PMU alarm control byte, with the alarm enable, the monitor bit and
+          the latched alarm event.
+      - description:
+          PMU alarm compare value, a 32-bit count of whole seconds of the RTC
+          counter without the offset.
+      - description: PMU alarm mask byte.
 
   nvmem-cell-names:
-    items:
-      - const: rtc_offset
+    oneOf:
+      - items:
+          - const: rtc_offset
+      - items:
+          - const: rtc_offset
+          - const: rtc_ctrl
+          - const: rtc_alarm
+          - const: rtc_alarm_mask
+
+  interrupts:
+    maxItems: 1
+    description:
+      The PMU's RTC alarm interrupt. Only used with the three alarm cells.
+
+  wakeup-source: true
 
   apple,rtc-offset-seconds:
     type: boolean

arch/arm64/boot/dts/apple/t6030.dtsi

@@ -1060,6 +1060,8 @@
 			#size-cells = <0>;
 			interrupt-parent = <&aic>;
 			interrupts = <AIC_IRQ 485 IRQ_TYPE_LEVEL_HIGH>;
+			interrupt-controller;
+			#interrupt-cells = <2>;
 
 			pmic1: pmic@b {
 				compatible = "apple,chapel-pmic", "apple,spmi-nvmem";
@@ -1070,10 +1072,22 @@
 					#address-cells = <1>;
 					#size-cells = <1>;
 
+					rtc_ctrl: rtc-ctrl@2000 {
+						reg = <0x2000 0x1>;
+					};
+
 					pm_setting: pm-setting@2001 {
 						reg = <0x2001 0x1>;
 					};
 
+					rtc_alarm: rtc-alarm@2008 {
+						reg = <0x2008 0x4>;
+					};
+
+					rtc_alarm_mask: rtc-alarm-mask@200e {
+						reg = <0x200e 0x1>;
+					};
+
 					rtc_offset: rtc-offset@2100 {
 						reg = <0x2100 0x6>;
 					};
@@ -1182,8 +1196,13 @@
 
 			rtc {
 				compatible = "apple,smc-rtc";
-				nvmem-cells = <&rtc_offset>;
-				nvmem-cell-names = "rtc_offset";
+				nvmem-cells = <&rtc_offset>, <&rtc_ctrl>, <&rtc_alarm>,
+					<&rtc_alarm_mask>;
+				nvmem-cell-names = "rtc_offset", "rtc_ctrl", "rtc_alarm",
+					"rtc_alarm_mask";
+				/* The PMIC's RTC alarm, peripheral interrupt 2 of nub-spmi0 */
+				interrupts-extended = <&nub_spmi 2 IRQ_TYPE_EDGE_RISING>;
+				wakeup-source;
 			};
 		};
 
@@ -1520,7 +1539,7 @@
 			port02: pci@2,0 {
 				device_type = "pci";
 				reg = <0x1000 0x0 0x0 0x0 0x0>;
 				reset-gpios = <&pinctrl_ap 169 GPIO_ACTIVE_LOW>; // perst
 
 				#address-cells = <3>;
 				#size-cells = <2>;
@@ -1547,7 +1566,7 @@
 				ranges;
 
 				interrupt-controller;
 				#interrupt-cells = <1>;
 
 				interrupt-map-mask = <0 0 0 7>;
 				interrupt-map = <0 0 0 1 &port03 0 0 0 0>,
@@ -2063,7 +2082,7 @@
 
 		dwc3_2: usb@f02280000 {
 			compatible = "apple,t6030-dwc3", "apple,t8103-dwc3";
 			reg = <0xf 0x02280000 0x0 0xcd00>, <0xf 0x0228cd00 0x0 0x3200>;
 			reg-names = "dwc3-core", "dwc3-apple";
 			interrupt-parent = <&aic>;
 			interrupts = <AIC_IRQ 1203 IRQ_TYPE_LEVEL_HIGH>;

drivers/gpu/drm/apple/dcp.c

@@ -4823,11 +4823,12 @@ static void dcp_release_after_sleep(struct apple_dcp *dcp)
 /*
  * Why an external processor must keep the system awake, or NULL. The manual
  * path refuses sleep once its firmware was ever started. A native processor
- * refuses while its firmware starts or holds a display link, and while a
- * display is attached to it at all, lit or not: resume does not bring an
- * attached display back. Idle with nothing attached, its firmware stays
- * powered across s2idle like the panel's (the gate holds its CPU domain at
- * the active floor) and the next attach reconnects through it.
+ * refuses while its firmware starts or a display is lit (user space turns
+ * displays off before sleep). A dark attached display sleeps with it:
+ * suspend releases an HDMI link and keeps a Type-C tunnel, and resume finds
+ * the display again as after DPMS off. Its firmware stays powered across
+ * s2idle like the panel's (the gate holds its CPU domain at the active
+ * floor), and the next attach reconnects through it.
  *
  * A processor that failed (its start, or its session later) never refuses
  * sleep: it drives no display until reboot, attached or not, and its power
@@ -4845,15 +4846,8 @@ static const char *dcp_external_sleep_vetoed(struct apple_dcp *dcp)
 	why = iomfb_v14_7_external_busy(dcp);
 	if (why)
 		return why;
-	if (iomfb_v14_7_external_failed(dcp)) {
-		if (dcp->v14)
-			dev_info(dcp->dev, "external display processor failed earlier: sleeping with it as it is\n");
-		return NULL;
-	}
-	if (READ_ONCE(dcp->active_typec_route) || READ_ONCE(dcp->typec_cable_connected))
-		return "a USB-C display is attached";
-	if (dcp->hdmi_hpd && gpiod_get_value_cansleep(dcp->hdmi_hpd) > 0)
-		return "an HDMI display is attached";
+	if (iomfb_v14_7_external_failed(dcp) && dcp->v14)
+		dev_info(dcp->dev, "external display processor failed earlier: sleeping with it as it is\n");
 	return NULL;
 }
 

drivers/gpu/drm/apple/iomfb_v14_7.c

@@ -19,6 +19,7 @@
 #include <linux/sizes.h>
 #include <linux/slab.h>
 #include <linux/soc/apple/pmp-report.h>
+#include <linux/suspend.h>
 #include <linux/soc/apple/rtkit.h>
 #include <linux/unaligned.h>
 #include <linux/workqueue.h>
@@ -304,8 +305,14 @@ struct apple_dcp_v14 {
 	enum dcp_v14_bl_gate bl_gate;
 	u32 nits_sent;
 	u64 nits_presents, brightness_presents, nits_refused;
+	/* Panel: its display controller is stopped (A472 hardware power off). */
+	bool panel_off;
 };
 
+static bool panel_hw_off = true;
+module_param(panel_hw_off, bool, 0644);
+MODULE_PARM_DESC(panel_hw_off, "Internal 14.7 panel: stop its display controller on DPMS off, not only blank it [default: true]");
+
 /*
  * The panel's DCP session; one per boot, RTKit is never started twice. The
  * manual external start waits for it, as the PMP runs once the panel's
@@ -1150,6 +1157,24 @@ static int dcp_v14_callback(void *cookie, u32 tag, const void *input, u32 in_siz
 	/* Swap information for a completed swap; the link checks its id. */
 	if (tag == D(589) && SHAPE(0x6f0, 0))
 		return 0;
+	/*
+	 * The panel's display-controller power transitions (A472 with the
+	 * hardware selector): will power off and an intent swap, both
+	 * notifications; display DART power and a kernel power assertion, both
+	 * held by the host throughout, so status 0; and the backlight message
+	 * at power on, which the backlight restore after A472(1) answers. Only
+	 * the J514S/J516S panel sends A472 so; elsewhere these stay unhandled.
+	 */
+	if (dcp_v14_board_nits(v14) &&
+	    ((tag == D(2) && SHAPE(0, 0)) || (tag == D(591) && SHAPE(20, 0)) ||
+	     (tag == D(593) && SHAPE(4, 0))))
+		return 0;
+	if (dcp_v14_board_nits(v14) && (tag == D(574) || tag == D(700)) && SHAPE(4, 4)) {
+		if (tag == D(574) && in[0] > 1)
+			return -EINVAL;
+		put_unaligned_le32(0, out);
+		return 0;
+	}
 	if ((tag == D(588) && SHAPE(8, 0)) || (tag == D(598) && SHAPE(0, 0)))
 		return 0;
 	/* Main-display query, answered by asking the firmware. */
@@ -2082,8 +2107,8 @@ bool iomfb_v14_7_external_ready(struct apple_dcp *dcp)
 
 /*
  * What this processor's firmware holds that system sleep would not hand
- * back, or NULL: a start in progress, or a display link or a powered
- * display. The caller also refuses sleep while a display is attached.
+ * back, or NULL: a start in progress, or a powered display. Suspend
+ * releases a dark display's link itself.
  */
 const char *iomfb_v14_7_external_busy(struct apple_dcp *dcp)
 {
@@ -2094,10 +2119,8 @@ const char *iomfb_v14_7_external_busy(struct apple_dcp *dcp)
 		/* A stopped session drives nothing, whatever it held last. */
 		if (dcp->v14 && READ_ONCE(dcp->v14->failed))
 			return NULL;
-		if (READ_ONCE(dcp->dptxport[0].connected) ||
-		    READ_ONCE(dcp->external_link_ready) ||
-		    (dcp->v14 && READ_ONCE(dcp->v14->powered)))
-			return "a display link is up";
+		if (dcp->v14 && READ_ONCE(dcp->v14->powered))
+			return "a display is lit";
 		return NULL;
 	default:
 		return NULL;
@@ -3108,6 +3131,32 @@ static int dcp_v14_set_power(struct apple_dcp_v14 *v14, bool on)
 	return ret;
 }
 
+/*
+ * A472 with the hardware selector (+8) and a null output word (+11): the
+ * panel's display controller off or on. Off stops scanout and the panel once
+ * a blank has been presented, on restarts them; the soft form (+8 clear)
+ * leaves the controller running. The client, the RTKit session and every
+ * mapping are kept.
+ */
+static int dcp_v14_panel_power(struct apple_dcp_v14 *v14, bool on)
+{
+	u8 in[12] = {}, out[8] = {};
+	int ret;
+
+	put_unaligned_le64(on, in);
+	in[8] = 1;
+	in[11] = 1;
+	ret = dcp_v14_call(v14, A(472), in, sizeof(in), out, sizeof(out), 0);
+	if (!ret && get_unaligned_le32(out + 4)) {
+		dev_err(v14->dev, "display controller %s refused: %#x\n", on ? "on" : "off",
+			get_unaligned_le32(out + 4));
+		ret = -EIO;
+	}
+	if (!ret)
+		v14->panel_off = !on;
+	return ret;
+}
+
 /* The display is fully described, and no description is in transfer. */
 static bool dcp_v14_external_described(struct apple_dcp_v14 *v14)
 {
@@ -3344,8 +3393,35 @@ void iomfb_v14_7_flush(struct apple_dcp *dcp, struct drm_crtc *crtc,
 		dcp_v14_cancel_event(dcp);
 }
 
+/* A system sleep is in progress, as opposed to a DPMS change. */
+static bool dcp_v14_system_sleep(void)
+{
+	KUNIT_STATIC_STUB_REDIRECT(dcp_v14_system_sleep);
+	return pm_suspend_in_progress();
+}
+
 void iomfb_v14_7_poweron(struct apple_dcp *dcp)
 {
+	struct apple_dcp_v14 *v14 = dcp->v14;
+	bool dark;
+
+	/*
+	 * The display controller first, then the backlight, as at boot. A
+	 * refused power on is tried once more. If the controller stays off,
+	 * so does the backlight, rather than light a dark panel; the next
+	 * power on tries again.
+	 */
+	if (!dcp->external && v14 && v14->panel_off) {
+		mutex_lock(&v14->lock);
+		if (v14->panel_off && dcp_v14_panel_power(v14, true))
+			dcp_v14_panel_power(v14, true);
+		dark = v14->panel_off;
+		mutex_unlock(&v14->lock);
+		if (dark) {
+			dev_err(dcp->dev, "display controller did not power on: backlight left off\n");
+			return;
+		}
+	}
 	/* The next present restores a level only after Linux has set one. */
 	if (dcp->v14 && dcp_v14_bl_dpms_applies(dcp->v14, dcp))
 		dcp_backlight_dpms(dcp, true);
@@ -3369,9 +3445,21 @@ void iomfb_v14_7_poweroff(struct apple_dcp *dcp)
 		dcp_mode_invalidate(&dcp->mode_state);
 		return;
 	}
-	/* Blank to black; the panel and the DCP stay powered. */
-	if (v14 && v14->started)
-		dcp_v14_blank(v14, dcp);
+	/* Blank to black, then stop the display controller; the DCP stays powered. */
+	if (!v14 || !v14->started)
+		return;
+	dcp_v14_blank(v14, dcp);
+	/*
+	 * Only the J514S/J516S panel, the one this was measured on, and only
+	 * on DPMS off: suspend-to-idle cuts that power itself.
+	 */
+	if (!panel_hw_off || !dcp_v14_board_nits(v14) || dcp_v14_system_sleep())
+		return;
+	mutex_lock(&v14->lock);
+	if (!v14->panel_off && !READ_ONCE(v14->failed) && !READ_ONCE(dcp->crashed) &&
+	    !v14->active_fb && dcp_v14_panel_power(v14, false))
+		dev_err(dcp->dev, "display controller did not power off\n");
+	mutex_unlock(&v14->lock);
 }
 
 #if IS_ENABLED(CONFIG_DRM_APPLE_DISPLAY_KUNIT_TEST)