i3c: master: svc: Fix npcm845 DAA process corruption

When MCONFIG.SKEW=0 and MCONFIG.ODHPP=0, the ENTDAA transaction gets
corrupted and results in a no repeated-start condition at the end of
address assignment.

Workaround: Set MCONFIG.SKEW to 1 before initiating the DAA process.
After the DAA process is completed, return MCONFIG.SKEW to its previous
value.

Reviewed-by: Frank Li <[email protected]>
Signed-off-by: Stanley Chu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

Author: stanleychuys

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

@@ -32,6 +32,7 @@
 #define   SVC_I3C_MCONFIG_ODBAUD(x) FIELD_PREP(GENMASK(23, 16), (x))
 #define   SVC_I3C_MCONFIG_ODHPP(x) FIELD_PREP(BIT(24), (x))
 #define   SVC_I3C_MCONFIG_SKEW(x) FIELD_PREP(GENMASK(27, 25), (x))
+#define   SVC_I3C_MCONFIG_SKEW_MASK GENMASK(27, 25)
 #define   SVC_I3C_MCONFIG_I2CBAUD(x) FIELD_PREP(GENMASK(31, 28), (x))
 
 #define SVC_I3C_MCTRL        0x084
@@ -150,6 +151,16 @@
  * If it is a true SlvStart, the MSTATUS state is SLVREQ.
  */
 #define SVC_I3C_QUIRK_FALSE_SLVSTART	BIT(1)
+/*
+ * SVC_I3C_QUIRK_DAA_CORRUPT:
+ * When MCONFIG.SKEW=0 and MCONFIG.ODHPP=0, the ENTDAA transaction gets
+ * corrupted and results in a no repeated-start condition at the end of
+ * address assignment.
+ * Workaround:
+ * Set MCONFIG.SKEW to 1 before initiating the DAA process. After the DAA
+ * process is completed, return MCONFIG.SKEW to its previous value.
+ */
+#define SVC_I3C_QUIRK_DAA_CORRUPT	BIT(2)
 
 struct svc_i3c_cmd {
 	u8 addr;
@@ -259,6 +270,13 @@ static inline bool svc_has_quirk(struct svc_i3c_master *master, u32 quirk)
 	return (master->drvdata->quirks & quirk);
 }
 
+static inline bool svc_has_daa_corrupt(struct svc_i3c_master *master)
+{
+	return ((master->drvdata->quirks & SVC_I3C_QUIRK_DAA_CORRUPT) &&
+		!(master->mctrl_config &
+		(SVC_I3C_MCONFIG_SKEW_MASK | SVC_I3C_MCONFIG_ODHPP(1))));
+}
+
 static inline bool is_events_enabled(struct svc_i3c_master *master, u32 mask)
 {
 	return !!(master->enabled_events & mask);
@@ -1146,7 +1164,16 @@ static int svc_i3c_master_do_daa(struct i3c_master_controller *m)
 	}
 
 	spin_lock_irqsave(&master->xferqueue.lock, flags);
+
+	if (svc_has_daa_corrupt(master))
+		writel(master->mctrl_config | SVC_I3C_MCONFIG_SKEW(1),
+		       master->regs + SVC_I3C_MCONFIG);
+
 	ret = svc_i3c_master_do_daa_locked(master, addrs, &dev_nb);
+
+	if (svc_has_daa_corrupt(master))
+		writel(master->mctrl_config, master->regs + SVC_I3C_MCONFIG);
+
 	spin_unlock_irqrestore(&master->xferqueue.lock, flags);
 
 	svc_i3c_master_clear_merrwarn(master);
@@ -2033,7 +2060,8 @@ static const struct dev_pm_ops svc_i3c_pm_ops = {
 
 static const struct svc_i3c_drvdata npcm845_drvdata = {
 	.quirks = SVC_I3C_QUIRK_FIFO_EMPTY |
-		SVC_I3C_QUIRK_FALSE_SLVSTART,
+		SVC_I3C_QUIRK_FALSE_SLVSTART |
+		SVC_I3C_QUIRK_DAA_CORRUPT,
 };
 
 static const struct svc_i3c_drvdata svc_default_drvdata = {};