diff options
| author | David Nyström <david.nystrom@est.tech> | 2026-02-19 21:58:03 +0100 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2026-04-12 16:32:11 +0200 |
| commit | 8ea0b60bc00d86b5ce33837487f4d16ae212f70a (patch) | |
| tree | 43c43892959917154ab7210e3d6537fbd2e248a2 /Documentation/ABI/testing | |
| parent | 335c21a2bb47585fdeb87c169d91f09b399c1d3d (diff) | |
i3c: master: Add sysfs option to rescan bus via entdaa
Allow userspace to request dynamic address assignment, which is
useful for i3cdev devices with broken hot-join support.
This will assign dynamic addresses to all devices on the I3C bus
which are currently unassigned.
Signed-off-by: David Nyström <david.nystrom@est.tech>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com>
Link: https://patch.msgid.link/20260219-i3c_rescan-v6-1-b81d6cc3cb30@est.tech
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'Documentation/ABI/testing')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-i3c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-i3c b/Documentation/ABI/testing/sysfs-bus-i3c index c1e048957a01..19f5cf8b1b11 100644 --- a/Documentation/ABI/testing/sysfs-bus-i3c +++ b/Documentation/ABI/testing/sysfs-bus-i3c @@ -172,3 +172,23 @@ Description: the automatic retries. Exist only when I3C constroller supports this retry on nack feature. +What: /sys/bus/i3c/devices/i3c-<bus-id>/do_daa +KernelVersion: 7.0 +Contact: linux-i3c@vger.kernel.org +Description: + Write-only attribute that triggers a Dynamic Address Assignment + (DAA) procedure which discovers new I3C devices on the bus. + Writing a boolean true value (1, y, yes, true, on) to this + attribute causes the master controller to perform DAA, which + includes broadcasting an ENTDAA (Enter Dynamic Address Assignment) + Common Command Code (CCC) on the bus. Writing a false value + returns -EINVAL. + + This is useful for discovering I3C devices that were not present + during initial bus initialization and are unable to issue + Hot-Join. Only devices without a currently assigned dynamic address + will respond to the ENTDAA broadcast and be assigned addresses. + + Note that this mechanism is distinct from Hot-Join, since this is + controller-initiated discovery, while Hot-Join is device-initiated + method to provoke controller discovery procedure. |