[PATCH v2 1/3] i3c: Add comment for -EAGAIN in i3c_device_do_priv_xfers()

From: Frank Li <Frank.Li@nxp.com>
To: miquel.raynal@bootlin.com
Cc: Frank.Li@nxp.com, alexandre.belloni@bootlin.com,
	conor.culhane@silvaco.com, imx@lists.linux.dev,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/3] i3c: Add comment for -EAGAIN in i3c_device_do_priv_xfers()
Date: Mon,  6 May 2024 12:40:07 -0400	[thread overview]
Message-ID: <20240506164009.21375-1-Frank.Li@nxp.com> (raw)

In accordance with I3C spec ver 1.1.1 09-Jun-2021, section: 5.1.2.2.3, if
a target requests hot join (HJ), In-Band Interrupt (IBI), or controller
role request (CRR) during the emission of an I3C address in
i3c_device_do_priv_xfers(), the target may win bus arbitration. In such
cases, it is imperative to notify the I3C client driver and retry
i3c_device_do_priv_xfers() after some delay.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---

Notes:
    Change from v1 to v2
    - new patch

 drivers/i3c/device.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
index 1a6a8703dbc3a..b04a55a1337d4 100644
--- a/drivers/i3c/device.c
+++ b/drivers/i3c/device.c
@@ -27,6 +27,10 @@
  * This function can sleep and thus cannot be called in atomic context.
  *
  * Return: 0 in case of success, a negative error core otherwise.
+ *	   -EAGAIN: controller lost address arbitration. Target
+ *		    (IBI, HJ or controller role request) win the bus. Client
+ *		    driver need resend this 'xfers' some time later.
+ *		    See I3C spec ver 1.1.1 09-Jun-2021. Section: 5.1.2.2.3.
  */
 int i3c_device_do_priv_xfers(struct i3c_device *dev,
 			     struct i3c_priv_xfer *xfers,
-- 
2.34.1


-- 
linux-i3c mailing list
linux-i3c@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-i3c
