From: Frank Li <Frank.Li@nxp.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
linux-i3c@lists.infradead.org (moderated list:SILVACO I3C
DUAL-ROLE MASTER),
imx@lists.linux.dev (open list:SILVACO I3C DUAL-ROLE MASTER),
linux-kernel@vger.kernel.org (open list)
Cc: imx@lists.linux.dev
Subject: [PATCH 1/1] i3c: master: svc: skip address resend on repeat START
Date: Wed, 16 Apr 2025 12:47:50 -0400 [thread overview]
Message-ID: <20250416164751.3437085-1-Frank.Li@nxp.com> (raw)
According to the I3C specification, address arbitration only happens during
the START. Repeated START do not initiate arbitration, and In-Band
Interrupts (IBIs) cannot occur at this stage.
Resending the address upon a NACK in a repeat START is therefore redundant
and unnecessary. Avoid redundant retries, improving efficiency and ensuring
protocol compliance.
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
drivers/i3c/master/svc-i3c-master.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 85e16de208d3b..5212c2cc6855f 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1281,9 +1281,9 @@ static int svc_i3c_master_write(struct svc_i3c_master *master,
static int svc_i3c_master_xfer(struct svc_i3c_master *master,
bool rnw, unsigned int xfer_type, u8 addr,
u8 *in, const u8 *out, unsigned int xfer_len,
- unsigned int *actual_len, bool continued)
+ unsigned int *actual_len, bool continued, bool repeat_start)
{
- int retry = 2;
+ int retry = repeat_start ? 1 : 2;
u32 reg;
int ret;
@@ -1468,7 +1468,7 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
ret = svc_i3c_master_xfer(master, cmd->rnw, xfer->type,
cmd->addr, cmd->in, cmd->out,
cmd->len, &cmd->actual_len,
- cmd->continued);
+ cmd->continued, !!i);
/* cmd->xfer is NULL if I2C or CCC transfer */
if (cmd->xfer)
cmd->xfer->actual_len = cmd->actual_len;
--
2.34.1
next reply other threads:[~2025-04-16 16:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-16 16:47 Frank Li [this message]
2025-04-23 7:17 ` [PATCH 1/1] i3c: master: svc: skip address resend on repeat START Miquel Raynal
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