Merge tag 'i3c/for-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux

Pull i3c updates from Alexandre Belloni:

 - svc: fix suspend/resume on some platforms, fix locking issues

* tag 'i3c/for-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
  i3c: master: svc: add NACK check after start byte sent
  i3c: master: svc: fix cpu schedule in spin lock
  i3c: master: svc: fix i3c suspend/resume issue

drivers/i3c/master/svc-i3c-master.c

@@ -92,6 +92,7 @@
 #define SVC_I3C_MINTCLR      0x094
 #define SVC_I3C_MINTMASKED   0x098
 #define SVC_I3C_MERRWARN     0x09C
+#define   SVC_I3C_MERRWARN_NACK BIT(2)
 #define SVC_I3C_MDMACTRL     0x0A0
 #define SVC_I3C_MDATACTRL    0x0AC
 #define   SVC_I3C_MDATACTRL_FLUSHTB BIT(0)
@@ -145,6 +146,11 @@ struct svc_i3c_xfer {
 	struct svc_i3c_cmd cmds[];
 };
 
+struct svc_i3c_regs_save {
+	u32 mconfig;
+	u32 mdynaddr;
+};
+
 /**
  * struct svc_i3c_master - Silvaco I3C Master structure
  * @base: I3C master controller
@@ -173,6 +179,7 @@ struct svc_i3c_master {
 	struct i3c_master_controller base;
 	struct device *dev;
 	void __iomem *regs;
+	struct svc_i3c_regs_save saved_regs;
 	u32 free_slots;
 	u8 addrs[SVC_I3C_MAX_DEVS];
 	struct i3c_dev_desc *descs[SVC_I3C_MAX_DEVS];
@@ -1008,6 +1015,11 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 	if (ret)
 		goto emit_stop;
 
+	if (readl(master->regs + SVC_I3C_MERRWARN) & SVC_I3C_MERRWARN_NACK) {
+		ret = -ENXIO;
+		goto emit_stop;
+	}
+
 	if (rnw)
 		ret = svc_i3c_master_read(master, in, xfer_len);
 	else
@@ -1090,12 +1102,6 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 	if (!xfer)
 		return;
 
-	ret = pm_runtime_resume_and_get(master->dev);
-	if (ret < 0) {
-		dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
-		return;
-	}
-
 	svc_i3c_master_clear_merrwarn(master);
 	svc_i3c_master_flush_fifo(master);
 
@@ -1110,9 +1116,6 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 			break;
 	}
 
-	pm_runtime_mark_last_busy(master->dev);
-	pm_runtime_put_autosuspend(master->dev);
-
 	xfer->ret = ret;
 	complete(&xfer->comp);
 
@@ -1133,6 +1136,13 @@ static void svc_i3c_master_enqueue_xfer(struct svc_i3c_master *master,
 					struct svc_i3c_xfer *xfer)
 {
 	unsigned long flags;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(master->dev);
+	if (ret < 0) {
+		dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
+		return;
+	}
 
 	init_completion(&xfer->comp);
 	spin_lock_irqsave(&master->xferqueue.lock, flags);
@@ -1143,6 +1153,9 @@ static void svc_i3c_master_enqueue_xfer(struct svc_i3c_master *master,
 		svc_i3c_master_start_xfer_locked(master);
 	}
 	spin_unlock_irqrestore(&master->xferqueue.lock, flags);
+
+	pm_runtime_mark_last_busy(master->dev);
+	pm_runtime_put_autosuspend(master->dev);
 }
 
 static bool
@@ -1579,10 +1592,28 @@ static void svc_i3c_master_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 }
 
+static void svc_i3c_save_regs(struct svc_i3c_master *master)
+{
+	master->saved_regs.mconfig = readl(master->regs + SVC_I3C_MCONFIG);
+	master->saved_regs.mdynaddr = readl(master->regs + SVC_I3C_MDYNADDR);
+}
+
+static void svc_i3c_restore_regs(struct svc_i3c_master *master)
+{
+	if (readl(master->regs + SVC_I3C_MDYNADDR) !=
+	    master->saved_regs.mdynaddr) {
+		writel(master->saved_regs.mconfig,
+		       master->regs + SVC_I3C_MCONFIG);
+		writel(master->saved_regs.mdynaddr,
+		       master->regs + SVC_I3C_MDYNADDR);
+	}
+}
+
 static int __maybe_unused svc_i3c_runtime_suspend(struct device *dev)
 {
 	struct svc_i3c_master *master = dev_get_drvdata(dev);
 
+	svc_i3c_save_regs(master);
 	svc_i3c_master_unprepare_clks(master);
 	pinctrl_pm_select_sleep_state(dev);
 
@@ -1596,6 +1627,8 @@ static int __maybe_unused svc_i3c_runtime_resume(struct device *dev)
 	pinctrl_pm_select_default_state(dev);
 	svc_i3c_master_prepare_clks(master);
 
+	svc_i3c_restore_regs(master);
+
 	return 0;
 }