[PATCH] i3c: master: svc: add NACK check after start byte sent
From: Clark Wang
Date: Tue May 16 2023 - 23:30:35 EST
Add NACK check after start byte is sent.
It is possible to detect early that a device is not on the bus
and avoid invalid transmissions thereafter.
Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
---
drivers/i3c/master/svc-i3c-master.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 4edf33ed207d..0d63b732ef0c 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/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)
@@ -1014,6 +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
--
2.34.1