From: Ovidiu Panait <ovidiu.panait.oss@gmail.com>
Date: Mon, 11 Aug 2025 08:54:17 +0000 (+0300)
Subject: staging: axis-fifo: use unique identifiers in device names
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e5b264e0a201254a38836b794ff362e8400f3df7;p=users%2Fhch%2Fmisc.git

staging: axis-fifo: use unique identifiers in device names

Axis-fifo devices use physical addresses in their name, for example
'axis_fifo_0x43c00000'. This is generally frowned upon and it does not
follow the usual naming scheme that uses unique identifiers.

Therefore, use ida_alloc()/ida_free() to implement unique identifiers
for axis-fifo device names (i.e. axis_fifo0, axis_fifo1, etc.).

Signed-off-by: Ovidiu Panait <ovidiu.panait.oss@gmail.com>
Link: https://lore.kernel.org/r/20250811085417.2641674-2-ovidiu.panait.oss@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
index 06f7cfab4c6a..e8aa632e0a31 100644
--- a/drivers/staging/axis-fifo/axis-fifo.c
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -107,6 +107,8 @@
 static long read_timeout = 1000; /* ms to wait before read() times out */
 static long write_timeout = 1000; /* ms to wait before write() times out */
 
+static DEFINE_IDA(axis_fifo_ida);
+
 /* ----------------------------
  * module command-line arguments
  * ----------------------------
@@ -123,6 +125,7 @@ MODULE_PARM_DESC(write_timeout, "ms to wait before blocking write() timing out;
  */
 
 struct axis_fifo {
+	int id;
 	int irq; /* interrupt */
 	void __iomem *base_addr; /* kernel space memory */
 
@@ -698,10 +701,6 @@ static int axis_fifo_probe(struct platform_device *pdev)
 
 	dev_dbg(fifo->dt_device, "remapped memory to 0x%p\n", fifo->base_addr);
 
-	/* create unique device name */
-	snprintf(device_name, 32, "%s_%pa", DRIVER_NAME, &r_mem->start);
-	dev_dbg(fifo->dt_device, "device name [%s]\n", device_name);
-
 	/* ----------------------------
 	 *          init IP
 	 * ----------------------------
@@ -737,6 +736,11 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	 *      init char device
 	 * ----------------------------
 	 */
+	fifo->id = ida_alloc(&axis_fifo_ida, GFP_KERNEL);
+	if (fifo->id < 0)
+		return fifo->id;
+
+	snprintf(device_name, 32, "%s%d", DRIVER_NAME, fifo->id);
 
 	/* create character device */
 	fifo->miscdev.fops = &fops;
@@ -744,8 +748,10 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	fifo->miscdev.name = device_name;
 	fifo->miscdev.parent = dev;
 	rc = misc_register(&fifo->miscdev);
-	if (rc < 0)
+	if (rc < 0) {
+		ida_free(&axis_fifo_ida, fifo->id);
 		return rc;
+	}
 
 	axis_fifo_debugfs_init(fifo);
 
@@ -759,6 +765,7 @@ static void axis_fifo_remove(struct platform_device *pdev)
 
 	debugfs_remove(fifo->debugfs_dir);
 	misc_deregister(&fifo->miscdev);
+	ida_free(&axis_fifo_ida, fifo->id);
 }
 
 static const struct of_device_id axis_fifo_of_match[] = {
@@ -798,6 +805,7 @@ module_init(axis_fifo_init);
 static void __exit axis_fifo_exit(void)
 {
 	platform_driver_unregister(&axis_fifo_driver);
+	ida_destroy(&axis_fifo_ida);
 }
 
 module_exit(axis_fifo_exit);