serial: core: Fix serial core controller port name to show controller id

We are missing the serial core controller id for the serial core port
name. Let's fix the issue for sane sysfs output, and to avoid issues
addressing serial ports later on.

And as we're now showing the controller id, the "ctrl" and "port" prefix
for the DEVNAME become useless, we can just drop them. Let's standardize on
DEVNAME:0 for controller name, where 0 is the controller id. And
DEVNAME:0.0 for port name, where 0.0 are the controller id and port id.

This makes the sysfs output nicer, on qemu for example:

$ ls /sys/bus/serial-base/devices
00:04:0         serial8250:0    serial8250:0.2
00:04:0.0       serial8250:0.1  serial8250:0.3

Fixes: 84a9582f ("serial: core: Start managing serial controllers to enable runtime PM")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230725054216.45696-4-tony@atomide.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_base_bus.c

@@ -19,6 +19,14 @@
 
 static bool serial_base_initialized;
 
+static const struct device_type serial_ctrl_type = {
+	.name = "ctrl",
+};
+
+static const struct device_type serial_port_type = {
+	.name = "port",
+};
+
 static int serial_base_match(struct device *dev, struct device_driver *drv)
 {
 	int len = strlen(drv->name);
@@ -48,7 +56,8 @@ static int serial_base_device_init(struct uart_port *port,
 				   struct device *parent_dev,
 				   const struct device_type *type,
 				   void (*release)(struct device *dev),
-				   int id)
+				   unsigned int ctrl_id,
+				   unsigned int port_id)
 {
 	device_initialize(dev);
 	dev->type = type;
@@ -61,12 +70,15 @@ static int serial_base_device_init(struct uart_port *port,
 		return -EPROBE_DEFER;
 	}
 
-	return dev_set_name(dev, "%s.%s.%d", type->name, dev_name(port->dev), id);
-}
+	if (type == &serial_ctrl_type)
+		return dev_set_name(dev, "%s:%d", dev_name(port->dev), ctrl_id);
 
-static const struct device_type serial_ctrl_type = {
-	.name = "ctrl",
-};
+	if (type == &serial_port_type)
+		return dev_set_name(dev, "%s:%d.%d", dev_name(port->dev),
+				    ctrl_id, port_id);
+
+	return -EINVAL;
+}
 
 static void serial_base_ctrl_release(struct device *dev)
 {
@@ -96,7 +108,7 @@ struct serial_ctrl_device *serial_base_ctrl_add(struct uart_port *port,
 	err = serial_base_device_init(port, &ctrl_dev->dev,
 				      parent, &serial_ctrl_type,
 				      serial_base_ctrl_release,
-				      port->ctrl_id);
+				      port->ctrl_id, 0);
 	if (err)
 		goto err_put_device;
 
@@ -112,10 +124,6 @@ struct serial_ctrl_device *serial_base_ctrl_add(struct uart_port *port,
 	return ERR_PTR(err);
 }
 
-static const struct device_type serial_port_type = {
-	.name = "port",
-};
-
 static void serial_base_port_release(struct device *dev)
 {
 	struct serial_port_device *port_dev = to_serial_base_port_device(dev);
@@ -136,7 +144,7 @@ struct serial_port_device *serial_base_port_add(struct uart_port *port,
 	err = serial_base_device_init(port, &port_dev->dev,
 				      &ctrl_dev->dev, &serial_port_type,
 				      serial_base_port_release,
-				      port->port_id);
+				      port->ctrl_id, port->port_id);
 	if (err)
 		goto err_put_device;