[PATCH] maple: switch to dynamic root device

[PATCH] maple: switch to dynamic root device

[Johan Hovold]

Driver core expects devices to be dynamically allocated and will, for
example, complain loudly when no release function has been provided.

Use root_device_register() to allocate and register the root device
instead of open coding using a static device.

Note that this also fixes a reference leak in case device_register()
fails which may be flagged by static checkers.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/sh/maple/maple.c | 30 +++++++++++-------------------
 1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/drivers/sh/maple/maple.c b/drivers/sh/maple/maple.c
index 5585f220e495..7c0f847ee368 100644
--- a/drivers/sh/maple/maple.c
+++ b/drivers/sh/maple/maple.c
@@ -44,7 +44,7 @@ static LIST_HEAD(maple_sentq);
 static DEFINE_MUTEX(maple_wlist_lock);
 
 static struct maple_driver maple_unsupported_device;
-static struct device maple_bus;
+static struct device *maple_bus;
 static int subdevice_map[MAPLE_PORTS];
 static unsigned long *maple_sendbuf, *maple_sendptr, *maple_lastptr;
 static unsigned long maple_pnp_time;
@@ -229,7 +229,7 @@ static struct maple_device *maple_alloc_dev(int port, int unit)
 		return NULL;
 	}
 	mdev->dev.bus = &maple_bus_type;
-	mdev->dev.parent = &maple_bus;
+	mdev->dev.parent = maple_bus;
 	init_waitqueue_head(&mdev->maple_wait);
 	return mdev;
 }
@@ -761,10 +761,6 @@ static int maple_match_bus_driver(struct device *devptr,
 	return 0;
 }
 
-static void maple_bus_release(struct device *dev)
-{
-}
-
 static struct maple_driver maple_unsupported_device = {
 	.drv = {
 		.name = "maple_unsupported_device",
@@ -779,11 +775,6 @@ static const struct bus_type maple_bus_type = {
 	.match = maple_match_bus_driver,
 };
 
-static struct device maple_bus = {
-	.init_name = "maple",
-	.release = maple_bus_release,
-};
-
 static int __init maple_bus_init(void)
 {
 	int retval, i;
@@ -791,9 +782,11 @@ static int __init maple_bus_init(void)
 
 	__raw_writel(0, MAPLE_ENABLE);
 
-	retval = device_register(&maple_bus);
-	if (retval)
+	maple_bus = root_device_register("maple");
+	if (IS_ERR(maple_bus)) {
+		retval = PTR_ERR(maple_bus);
 		goto cleanup;
+	}
 
 	retval = bus_register(&maple_bus_type);
 	if (retval)
@@ -806,22 +799,21 @@ static int __init maple_bus_init(void)
 	/* allocate memory for maple bus dma */
 	retval = maple_get_dma_buffer();
 	if (retval) {
-		dev_err(&maple_bus, "failed to allocate DMA buffers\n");
+		dev_err(maple_bus, "failed to allocate DMA buffers\n");
 		goto cleanup_basic;
 	}
 
 	/* set up DMA interrupt handler */
 	retval = maple_set_dma_interrupt_handler();
 	if (retval) {
-		dev_err(&maple_bus, "bus failed to grab maple "
-			"DMA IRQ\n");
+		dev_err(maple_bus, "bus failed to grab maple DMA IRQ\n");
 		goto cleanup_dma;
 	}
 
 	/* set up VBLANK interrupt handler */
 	retval = maple_set_vblank_interrupt_handler();
 	if (retval) {
-		dev_err(&maple_bus, "bus failed to grab VBLANK IRQ\n");
+		dev_err(maple_bus, "bus failed to grab VBLANK IRQ\n");
 		goto cleanup_irq;
 	}
 
@@ -855,7 +847,7 @@ static int __init maple_bus_init(void)
 	maple_pnp_time = jiffies + HZ;
 	/* prepare initial queue */
 	maple_send();
-	dev_info(&maple_bus, "bus core now registered\n");
+	dev_info(maple_bus, "bus core now registered\n");
 
 	return 0;
 
@@ -878,7 +870,7 @@ static int __init maple_bus_init(void)
 	bus_unregister(&maple_bus_type);
 
 cleanup_device:
-	device_unregister(&maple_bus);
+	root_device_unregister(maple_bus);
 
 cleanup:
 	printk(KERN_ERR "Maple bus registration failed\n");
-- 
2.53.0

Re: [PATCH] maple: switch to dynamic root device

[Artur Rojek]

On 2026-04-24 12:41, Johan Hovold wrote:
> Driver core expects devices to be dynamically allocated and will, for
> example, complain loudly when no release function has been provided.
> 
> Use root_device_register() to allocate and register the root device
> instead of open coding using a static device.
> 
> Note that this also fixes a reference leak in case device_register()
> fails which may be flagged by static checkers.
> 
> Signed-off-by: Johan Hovold <johan@kernel.org>

Hi Johan,

thanks for the patch. Verified on real hardware. LGTM:

Acked-by: Artur Rojek <contact@artur-rojek.eu>

Re: [PATCH] maple: switch to dynamic root device

[John Paul Adrian Glaubitz]

Hi Artur,

On Fri, 2026-04-24 at 21:08 +0200, Artur Rojek wrote:
> On 2026-04-24 12:41, Johan Hovold wrote:
> > Driver core expects devices to be dynamically allocated and will, for
> > example, complain loudly when no release function has been provided.
> > 
> > Use root_device_register() to allocate and register the root device
> > instead of open coding using a static device.
> > 
> > Note that this also fixes a reference leak in case device_register()
> > fails which may be flagged by static checkers.
> > 
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> 
> Hi Johan,
> 
> thanks for the patch. Verified on real hardware. LGTM:
> 
> Acked-by: Artur Rojek <contact@artur-rojek.eu>

Maybe add a Tested-by as well.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: [PATCH] maple: switch to dynamic root device

[Artur Rojek]

On 2026-04-24 21:59, John Paul Adrian Glaubitz wrote:
> Hi Artur,
> 
> On Fri, 2026-04-24 at 21:08 +0200, Artur Rojek wrote:
>> On 2026-04-24 12:41, Johan Hovold wrote:
>> > Driver core expects devices to be dynamically allocated and will, for
>> > example, complain loudly when no release function has been provided.
>> >
>> > Use root_device_register() to allocate and register the root device
>> > instead of open coding using a static device.
>> >
>> > Note that this also fixes a reference leak in case device_register()
>> > fails which may be flagged by static checkers.
>> >
>> > Signed-off-by: Johan Hovold <johan@kernel.org>
>> 
>> Hi Johan,
>> 
>> thanks for the patch. Verified on real hardware. LGTM:
>> 
>> Acked-by: Artur Rojek <contact@artur-rojek.eu>
> 
> Maybe add a Tested-by as well.

Tested-by: Artur Rojek <contact@artur-rojek.eu>

> 
> Adrian