[PATCH V2 01/16] i3c: mipi-i3c-hci: Fix suspend behavior when bus disable falls back to software reset

Adrian Hunter
2026-04-21T17:54:50Z

Software reset was introduced as a fallback if bus disable failed. The
change was made in 2 places: the cleanup path and the suspend path.

For the cleanup path (i3c_hci_bus_cleanup()), after software reset the
function continues to do cleanup for the current I/O mode. For the
suspend path (i3c_hci_rpm_suspend()), after software reset the function
returns early. However software reset does not reset any Ring Headers in
the Host Controller, so returning early is not the right thing to do.

Instead, continue to call suspend for the current I/O mode, which for DMA
mode will reset any Ring Headers.

Note, although Ring Headers should not be active at this stage, performing
this reset follows the procedure defined by the specification and keeps
the suspend path consistent with the cleanup path.

Note also, i3c_hci_sync_irq_inactive() is still called via the PIO and DMA
hci->io->suspend() callbacks.

Always return 0 because the device is quiesced as much as possible and
returning a negative error code would unnecessarily prevent system suspend.

Fixes: 9a258d1336f7 ("i3c: mipi-i3c-hci: Fallback to software reset when bus disable fails")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---

Changes in V2:

Always return 0 from suspend callback
Amend commit message

drivers/i3c/master/mipi-i3c-hci/core.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index b781dbed2165..afb0764b5e1f 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -762,15 +762,10 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
int i3c_hci_rpm_suspend(struct device *dev)
{
struct i3c_hci *hci = dev_get_drvdata(dev);
- int ret;

- ret = i3c_hci_bus_disable(hci);
- if (ret) {
- /* Fall back to software reset to disable the bus */
- ret = i3c_hci_software_reset(hci);
- i3c_hci_sync_irq_inactive(hci);
- return ret;
- }
+ /* Fall back to software reset to disable the bus */
+ if (i3c_hci_bus_disable(hci))
+ i3c_hci_software_reset(hci);

hci->io->suspend(hci);

--
2.51.0