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 06f7cfab4c6aa2d0fae9754e7b7295f9437d7679..e8aa632e0a3107fbdb6850b13465f64a28624439 100644 (file)
--- 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);