i3c: master: Match ACPI targets to the correct bus controller instance

For ACPI-enumerated I3C targets, _ADR encodes both the zero-based bus
controller instance number in bits 51:48 and the Provisioned ID (PID)
in bits 47:0, as defined by ACPI 6.6 Table 6.2 and MIPI DisCo for I3C
v1.1 section 5.2.

However, i3c_master_add_acpi_dev() treats the entire _ADR value as the
PID. On multi-instance controllers this folds the instance number into
the PID, causing i3c_master_add_i3c_boardinfo() to reject devices on
instance 1 and above with -EINVAL.

The problem is exposed by the MIPI I3C HCI PCI driver, which creates one
MFD child device per bus controller instance. Since the child devices do
not have their own ACPI companions, they all inherit the parent's ACPI
node and therefore enumerate the same set of child devices. As a result,
a target belonging to any instance other than 0 prevents registration of
all controller instances.

Add an instance number to struct i3c_master_controller, propagate it
from the HCI PCI driver, extract the PID from bits 47:0 of _ADR, and
ignore ACPI child nodes that belong to a different controller instance.

ACPI-enumerated I2C devices are unaffected. Their controller instance is
encoded in the Resource Source Index of the I2cSerialBusV2 descriptor
rather than in _ADR and will require separate handling.

Fixes: b46a4b3c5d1e ("i3c: master: Support ACPI enumeration of child devices")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260920151248.46936-5-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

2 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index f7ceec2b4477..72065715feee 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -536,6 +536,8 @@ struct i3c_master_controller_ops {
  *		 Bit 0: SETDASA
  *		 Bit 1: SETAASA
  *		 All other bits are reserved.
+ * @instance: Zero-based instance number of the Bus Controller as defined by the
+ *            DisCo specification I3C Target Address (_ADR) Encoding
  * @wq: freezable workqueue which can be used by master
  *	drivers if they need to postpone operations that need to take place
  *	in a thread context. Typical examples are Hot Join processing which
@@ -573,6 +575,7 @@ struct i3c_master_controller {
 	} boardinfo;
 	struct i3c_bus bus;
 	u8 addr_method;
+	u8 instance;
 	struct workqueue_struct *wq;
 	struct work_struct hj_work;
 	struct work_struct reg_work;
diff --git a/include/linux/platform_data/mipi-i3c-hci.h b/include/linux/platform_data/mipi-i3c-hci.h
index ab7395f455f9..6f61d8a02378 100644
--- a/include/linux/platform_data/mipi-i3c-hci.h
+++ b/include/linux/platform_data/mipi-i3c-hci.h
@@ -3,13 +3,17 @@
 #define INCLUDE_PLATFORM_DATA_MIPI_I3C_HCI_H
 
 #include <linux/compiler_types.h>
+#include <linux/types.h>
 
 /**
  * struct mipi_i3c_hci_platform_data - Platform-dependent data for mipi_i3c_hci
  * @base_regs: Register set base address (to support multi-bus instances)
+ * @instance: Zero-based instance number of the Bus Controller as defined by the
+ *            DisCo specification I3C Target Address (_ADR) Encoding
  */
 struct mipi_i3c_hci_platform_data {
 	void __iomem *base_regs;
+	u8 instance;
 };
 
 #endif