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WARM3d

Revision v3 of 2 in this series.

Revisions (2)
  1. v1 [diff vs current]
  2. v3 current

[PATCH net-next v3 2/3] bus: mhi: host: pci_generic: enumerate IP_CTRL channel for Sierra EM919x/EM929x

From: Peter Hunt <hidden>
Date: 2026-08-07 21:51:17
Also in: linux-arm-msm, lkml
Subsystem: mhi bus, the rest · Maintainers: Manivannan Sadhasivam, Linus Torvalds

IP_CTRL is a standard Qualcomm MHI control channel (channels 18/19) that
carries the host serial control lines (DTR/RTS) to the modem; it is not
Sierra-specific. It was not enumerated for any device in pci_generic, so
the host had no way to drive those signals.

Enumerate it in the Sierra em919x channel config (shared by the EM919x
and EM929x) using the control event ring. This is the device the change
was tested against; other Qualcomm modem configs that expose IP_CTRL can
enable it the same way, since the mhi_wwan_ctrl DTR support that consumes
it is device-agnostic and binds purely by channel name.

Signed-off-by: Peter Hunt <redacted>
---
 drivers/bus/mhi/host/pci_generic.c | 2 ++
 1 file changed, 2 insertions(+)
diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
index 0d0d9c7ffa4b..ba47dd153837 100644
--- a/drivers/bus/mhi/host/pci_generic.c
+++ b/drivers/bus/mhi/host/pci_generic.c
@@ -728,6 +728,8 @@ static const struct mhi_channel_config mhi_sierra_em919x_channels[] = {
 	MHI_CHANNEL_CONFIG_DL(13, "MBIM", 128, 0),
 	MHI_CHANNEL_CONFIG_UL(14, "QMI", 32, 0),
 	MHI_CHANNEL_CONFIG_DL(15, "QMI", 32, 0),
+	MHI_CHANNEL_CONFIG_UL(18, "IP_CTRL", 32, 0),
+	MHI_CHANNEL_CONFIG_DL(19, "IP_CTRL", 32, 0),
 	MHI_CHANNEL_CONFIG_UL(32, "DUN", 32, 0),
 	MHI_CHANNEL_CONFIG_DL(33, "DUN", 32, 0),
 	MHI_CHANNEL_CONFIG_HW_UL(100, "IP_HW0", 512, 1),
-- 
2.43.0
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