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i3c: mipi-i3c-hci: Reset RING_OPERATION1 fields during init

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The MIPI I3C HCI specification does not define reset values for
RING_OPERATION1 fields, and some controllers (e.g., Intel) do not clear
them during a software reset.  Ensure the ring pointers are explicitly
set to zero during bus initialization to avoid inconsistent state.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260113072702.16268-2-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Adrian Hunter
2026-01-13 09:26:42 +02:00
committed by Alexandre Belloni
parent 3502cea99c
commit 78f63ae4a8
1 changed files with 8 additions and 0 deletions
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8
drivers/i3c/master/mipi-i3c-hci/dma.c
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@@ -340,6 +340,14 @@ static int hci_dma_init(struct i3c_hci *hci)
rh_reg_write(INTR_SIGNAL_ENABLE, regval);
ring_ready:
/*
* The MIPI I3C HCI specification does not document reset values for
* RING_OPERATION1 fields and some controllers (e.g. Intel controllers)
* do not reset the values, so ensure the ring pointers are set to zero
* here.
*/
rh_reg_write(RING_OPERATION1, 0);
rh_reg_write(RING_CONTROL, RING_CTRL_ENABLE |
RING_CTRL_RUN_STOP);
}