ipmi:ipmb: Add OF support

Add direct OF support for fetching control parameters from the device
tree.  Make it work like the device tree entries for the other IPMI
devices.  Also add documentation for this.

Signed-off-by: Corey Minyard <[email protected]>

Author: cminyard

Documentation/devicetree/bindings/ipmi/ipmi-ipmb.yaml

@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ipmi/ipmi-ipmb.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: IPMI IPMB device bindings
+
+description: IPMI IPMB device bindings
+
+maintainers:
+  - Corey Minyard <[email protected]>
+
+properties:
+  compatible:
+    enum:
+      - ipmi-ipmb
+
+  device_type:
+    items:
+      - const: "ipmi"
+
+  reg:
+    maxItems: 1
+
+  bmcaddr:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description: The address of the BMC on the IPMB bus.  Defaults to 0x20.
+
+  retry-time:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Time between retries of sends, in milliseconds.  Defaults to 250.
+
+  max-retries:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Number of retries before a failure is declared.  Defaults to 1.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            ipmi-ipmb@40 {
+                    compatible = "ipmi-ipmb";
+                    device_type = "ipmi";
+                    reg = <0x40>;
+                    bmcaddr = /bits/ 8 <0x20>;
+                    retry-time = <250>;
+                    max-retries = <1>;
+            };
+    };

drivers/char/ipmi/ipmi_ipmb.c

@@ -44,10 +44,12 @@ struct ipmi_ipmb_dev {
 
 	bool ready;
 
-	u8 bmcaddr;
-
 	u8 curr_seq;
 
+	u8 bmcaddr;
+	u32 retry_time_ms;
+	u32 max_retries;
+
 	struct ipmi_smi_msg *next_msg;
 	struct ipmi_smi_msg *working_msg;
 
@@ -333,7 +335,7 @@ static int ipmi_ipmb_thread(void *data)
 
 		/* A command was sent, wait for its response. */
 		ret = down_timeout(&iidev->got_rsp,
-				   msecs_to_jiffies(retry_time_ms));
+				   msecs_to_jiffies(iidev->retry_time_ms));
 
 		/*
 		 * Grab the message if we can.  If the handler hasn't
@@ -353,7 +355,7 @@ static int ipmi_ipmb_thread(void *data)
 			 * the semaphore.
 			 */
 			down(&iidev->got_rsp);
-		} else if (msg && ++retries <= max_retries) {
+		} else if (msg && ++retries <= iidev->max_retries) {
 			spin_lock_irqsave(&iidev->lock, flags);
 			iidev->working_msg = msg;
 			spin_unlock_irqrestore(&iidev->lock, flags);
@@ -437,14 +439,30 @@ static int ipmi_ipmb_remove(struct i2c_client *client)
 static int ipmi_ipmb_probe(struct i2c_client *client,
 			   const struct i2c_device_id *id)
 {
+	struct device *dev = &client->dev;
 	struct ipmi_ipmb_dev *iidev;
 	int rv;
 
 	iidev = devm_kzalloc(&client->dev, sizeof(*iidev), GFP_KERNEL);
 	if (!iidev)
 		return -ENOMEM;
 
-	iidev->bmcaddr = bmcaddr;
+	if (of_property_read_u8(dev->of_node, "bmcaddr", &iidev->bmcaddr) != 0)
+		iidev->bmcaddr = bmcaddr;
+	if (iidev->bmcaddr == 0 || iidev->bmcaddr & 1) {
+		/* Can't have the write bit set. */
+		dev_notice(&client->dev,
+			   "Invalid bmc address value %2.2x\n", iidev->bmcaddr);
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32(dev->of_node, "retry-time",
+				 &iidev->retry_time_ms) != 0)
+		iidev->retry_time_ms = retry_time_ms;
+
+	if (of_property_read_u32(dev->of_node, "max-retries",
+				 &iidev->max_retries) != 0)
+		iidev->max_retries = max_retries;
 
 	i2c_set_clientdata(client, iidev);
 	client->flags |= I2C_CLIENT_SLAVE;
@@ -488,6 +506,16 @@ static int ipmi_ipmb_probe(struct i2c_client *client,
 	return rv;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id of_ipmi_ipmb_match[] = {
+	{ .type = "ipmi", .compatible = DEVICE_NAME },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_ipmi_ipmb_match);
+#else
+#define of_ipmi_ipmb_match NULL
+#endif
+
 static const struct i2c_device_id ipmi_ipmb_id[] = {
 	{ DEVICE_NAME, 0 },
 	{},
@@ -498,6 +526,7 @@ static struct i2c_driver ipmi_ipmb_driver = {
 	.class		= I2C_CLASS_HWMON,
 	.driver = {
 		.name = DEVICE_NAME,
+		.of_match_table = of_ipmi_ipmb_match,
 	},
 	.probe		= ipmi_ipmb_probe,
 	.remove		= ipmi_ipmb_remove,