From c64b23a583fb987e93528033bf6033918cbaf105 Mon Sep 17 00:00:00 2001
From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Tue, 2 Jul 2024 21:54:47 +0200
Subject: [PATCH 1/2] i2c: Include device name in check i2c_check_addr_busy()

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/i2c/i2c-core-base.c | 50 ++++++++++++++++++++++++-------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 49fdcb3eb..a6c2974b9 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -779,55 +779,67 @@ int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 	return 0;
 }
 
-static int __i2c_check_addr_busy(struct device *dev, void *addrp)
+static int __i2c_check_addr_busy(struct device *dev, void *data)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
-	int			addr = *(int *)addrp;
+	struct i2c_client	*cl = data;
+
+	if (client && i2c_encode_flags_to_addr(client) == cl->addr) {
+		if (strcmp(client->name, cl->name))
+			return -EBUSY;
+		else
+			/*
+			 * If we find a device with the same name on the address,
+			 * then assume we have been instantiated by other means already
+			 */
+			return -EEXIST;
+	}
 
-	if (client && i2c_encode_flags_to_addr(client) == addr)
-		return -EBUSY;
 	return 0;
 }
 
 /* walk up mux tree */
-static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
+static int i2c_check_mux_parents(struct i2c_adapter *adapter, struct i2c_client *cl)
 {
 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 	int result;
 
-	result = device_for_each_child(&adapter->dev, &addr,
-					__i2c_check_addr_busy);
+	result = device_for_each_child(&adapter->dev, cl, __i2c_check_addr_busy);
 
 	if (!result && parent)
-		result = i2c_check_mux_parents(parent, addr);
+		result = i2c_check_mux_parents(parent, cl);
 
 	return result;
 }
 
 /* recurse down mux tree */
-static int i2c_check_mux_children(struct device *dev, void *addrp)
+static int i2c_check_mux_children(struct device *dev, void *cl)
 {
 	int result;
 
 	if (dev->type == &i2c_adapter_type)
-		result = device_for_each_child(dev, addrp,
-						i2c_check_mux_children);
+		result = device_for_each_child(dev, cl, i2c_check_mux_children);
 	else
-		result = __i2c_check_addr_busy(dev, addrp);
+		result = __i2c_check_addr_busy(dev, cl);
 
 	return result;
 }
 
-static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
+static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr, const char *name)
 {
 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+	struct i2c_client cl = {};
 	int result = 0;
 
+	cl.addr = addr;
+	if (name)
+		strscpy(cl.name, name, sizeof(cl.name));
+
 	if (parent)
-		result = i2c_check_mux_parents(parent, addr);
+		result = i2c_check_mux_parents(parent, &cl);
 
 	if (!result)
-		result = device_for_each_child(&adapter->dev, &addr,
+		result = device_for_each_child(&adapter->dev, &cl,
 						i2c_check_mux_children);
 
 	return result;
@@ -963,7 +975,9 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 	}
 
 	/* Check for address business */
-	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
+	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client), client->name);
+	if (status == -EEXIST)
+		goto out_err_silent;
 	if (status)
 		goto out_err;
 
@@ -2444,7 +2458,7 @@ static int i2c_detect_address(struct i2c_client *temp_client,
 	}
 
 	/* Skip if already in use (7 bit, no need to encode flags) */
-	if (i2c_check_addr_busy(adapter, addr))
+	if (i2c_check_addr_busy(adapter, addr, NULL))
 		return 0;
 
 	/* Make sure there is something at this address */
@@ -2559,7 +2573,7 @@ i2c_new_scanned_device(struct i2c_adapter *adap,
 		}
 
 		/* Check address availability (7 bit, no need to encode flags) */
-		if (i2c_check_addr_busy(adap, addr_list[i])) {
+		if (i2c_check_addr_busy(adap, addr_list[i], NULL)) {
 			dev_dbg(&adap->dev,
 				"Address 0x%02x already in use, not probing\n",
 				addr_list[i]);
-- 
2.45.2