Merge branch 'mctp-i2c'

Matt Johnston says:

====================
MCTP I2C driver

This patch series adds a netdev driver providing MCTP transport over
I2C.

I think I've addressed all the points raised in v5. It now has
mctp_i2c_unregister() to run things in the correct order, waiting for
the worker thread and I2C rx to complete.

Cheers,
Matt

--

v6:
 - Changed netdev register/unregister/free to avoid races. Ensure that
   netif functions are not used by irq handler/threads after unregister.
 - Fix incoming I2C hwaddr that was previously incorrect (left
   shifted 1 bit)
 - Add a check that byte_count wire header matches the length received
 - Renamed I2C driver to mctp-i2c-interface
 - Removed __func__ from print messages, added missing newlines
 - Removed sysfs mctp_current_mux file which was used for debug
 - Renamed curr_lock to sel_lock
 - Tidied comment formatting
 - Fix newline in Kconfig
v5:
 - Fix incorrect format string
v4:
 - Switch to __i2c_transfer() rather than __i2c_smbus_xfer(), drop 255 byte
   smbus patches
 - Use wait_event_idle() for the sleeping TX thread
 - Use dev_addr_set()
v3:
 - Added Reviewed-bys for npcm7xx
 - Resend with net-next open
v2:
 - Simpler Kconfig condition for i2c-mux dependency, from Randy Dunlap
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/i2c/i2c.txt

@@ -95,6 +95,10 @@ wants to support one of the below features, it should adapt these bindings.
 - smbus-alert
 	states that the optional SMBus-Alert feature apply to this bus.
 
+- mctp-controller
+	indicates that the system is accessible via this bus as an endpoint for
+	MCTP over I2C transport.
+
 Required properties (per child device)
 --------------------------------------
 

Documentation/devicetree/bindings/net/mctp-i2c-controller.yaml

@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/mctp-i2c-controller.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MCTP I2C transport binding
+
+maintainers:
+  - Matt Johnston <matt@codeconstruct.com.au>
+
+description: |
+  An mctp-i2c-controller defines a local MCTP endpoint on an I2C controller.
+  MCTP I2C is specified by DMTF DSP0237.
+
+  An mctp-i2c-controller must be attached to an I2C adapter which supports
+  slave functionality. I2C busses (either directly or as subordinate mux
+  busses) are attached to the mctp-i2c-controller with a 'mctp-controller'
+  property on each used bus. Each mctp-controller I2C bus will be presented
+  to the host system as a separate MCTP I2C instance.
+
+properties:
+  compatible:
+    const: mctp-i2c-controller
+
+  reg:
+    minimum: 0x40000000
+    maximum: 0x4000007f
+    description: |
+      7 bit I2C address of the local endpoint.
+      I2C_OWN_SLAVE_ADDRESS (1<<30) flag must be set.
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    // Basic case of a single I2C bus
+    #include <dt-bindings/i2c/i2c.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      mctp-controller;
+
+      mctp@30 {
+        compatible = "mctp-i2c-controller";
+        reg = <(0x30 | I2C_OWN_SLAVE_ADDRESS)>;
+      };
+    };
+
+  - |
+    // Mux topology with multiple MCTP-handling busses under
+    // a single mctp-i2c-controller.
+    // i2c1 and i2c6 can have MCTP devices, i2c5 does not.
+    #include <dt-bindings/i2c/i2c.h>
+
+    i2c1: i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      mctp-controller;
+
+      mctp@50 {
+        compatible = "mctp-i2c-controller";
+        reg = <(0x50 | I2C_OWN_SLAVE_ADDRESS)>;
+      };
+    };
+
+    i2c-mux {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      i2c-parent = <&i2c1>;
+
+      i2c5: i2c@0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <0>;
+        eeprom@33 {
+          reg = <0x33>;
+        };
+      };
+
+      i2c6: i2c@1 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <1>;
+        mctp-controller;
+      };
+    };

drivers/net/mctp/Kconfig

@@ -21,6 +21,18 @@ config MCTP_SERIAL
 	  Say y here if you need to connect to MCTP endpoints over serial. To
 	  compile as a module, use m; the module will be called mctp-serial.
 
+config MCTP_TRANSPORT_I2C
+	tristate "MCTP SMBus/I2C transport"
+	# i2c-mux is optional, but we must build as a module if i2c-mux is a module
+	depends on I2C_MUX || !I2C_MUX
+	depends on I2C
+	depends on I2C_SLAVE
+	select MCTP_FLOWS
+	help
+	  Provides a driver to access MCTP devices over SMBus/I2C transport,
+	  from DMTF specification DSP0237. A MCTP protocol network device is
+	  created for each I2C bus that has been assigned a mctp-i2c device.
+
 endmenu
 
 endif

drivers/net/mctp/Makefile

@@ -1 +1,2 @@
 obj-$(CONFIG_MCTP_SERIAL) += mctp-serial.o
+obj-$(CONFIG_MCTP_TRANSPORT_I2C) += mctp-i2c.o