i3c: Add comment for -EAGAIN in i3c_device_do_priv_xfers()

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>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20240506164009.21375-1-Frank.Li@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
index 1a6a8703dbc3aa61b40e39eb09e40e72e6089b92..e80e4875691467cf2c898744b25c57b71ee82f91 100644 (file)
--- 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 needs to resend the '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,