| Message ID | 20230517033030.3068085-3-xiaoning.wang@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | i3c: master: svc: add NACK check after start byte sent | expand |
Hi Clark, xiaoning.wang@nxp.com wrote on Wed, 17 May 2023 11:30:30 +0800: > 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@nxp.com> Nice addition. Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> > --- > 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 Thanks, Miquèl
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
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@nxp.com> --- drivers/i3c/master/svc-i3c-master.c | 6 ++++++ 1 file changed, 6 insertions(+)