[v3,4/5] amba: Make the remove callback return void

All amba drivers return 0 in their remove callback. Together with the
driver core ignoring the return value anyhow, it doesn't make sense to
return a value here.

Change the remove prototype to return void, which makes it explicit that
returning an error value doesn't work as expected. This simplifies changing
the core remove callback to return void, too.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/amba/bus.c                                 | 5 ++---
 drivers/char/hw_random/nomadik-rng.c               | 3 +--
 drivers/dma/pl330.c                                | 3 +--
 drivers/gpu/drm/pl111/pl111_drv.c                  | 4 +---
 drivers/hwtracing/coresight/coresight-catu.c       | 3 +--
 drivers/hwtracing/coresight/coresight-cpu-debug.c  | 4 +---
 drivers/hwtracing/coresight/coresight-cti-core.c   | 4 +---
 drivers/hwtracing/coresight/coresight-etb10.c      | 4 +---
 drivers/hwtracing/coresight/coresight-etm3x-core.c | 4 +---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 +---
 drivers/hwtracing/coresight/coresight-funnel.c     | 4 ++--
 drivers/hwtracing/coresight/coresight-replicator.c | 4 ++--
 drivers/hwtracing/coresight/coresight-stm.c        | 4 +---
 drivers/hwtracing/coresight/coresight-tmc-core.c   | 4 +---
 drivers/hwtracing/coresight/coresight-tpiu.c       | 4 +---
 drivers/i2c/busses/i2c-nomadik.c                   | 4 +---
 drivers/input/serio/ambakmi.c                      | 3 +--
 drivers/memory/pl172.c                             | 4 +---
 drivers/memory/pl353-smc.c                         | 4 +---
 drivers/mmc/host/mmci.c                            | 4 +---
 drivers/rtc/rtc-pl030.c                            | 4 +---
 drivers/rtc/rtc-pl031.c                            | 4 +---
 drivers/spi/spi-pl022.c                            | 5 ++---
 drivers/tty/serial/amba-pl010.c                    | 4 +---
 drivers/tty/serial/amba-pl011.c                    | 3 +--
 drivers/vfio/platform/vfio_amba.c                  | 3 +--
 drivers/video/fbdev/amba-clcd.c                    | 4 +---
 drivers/watchdog/sp805_wdt.c                       | 4 +---
 include/linux/amba/bus.h                           | 2 +-
 sound/arm/aaci.c                                   | 4 +---
 30 files changed, 34 insertions(+), 80 deletions(-)

Hi

On 1/26/21 4:58 PM, Uwe Kleine-König wrote:
> All amba drivers return 0 in their remove callback. Together with the
> driver core ignoring the return value anyhow, it doesn't make sense to
> return a value here.
> 
> Change the remove prototype to return void, which makes it explicit that
> returning an error value doesn't work as expected. This simplifies changing
> the core remove callback to return void, too.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> Acked-by: Mark Brown <broonie@kernel.org>
  > Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>


>   drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 +---

You are most likely to have a conflict for the above file, with what is
in coresight/next. It should be easy to resolve.

Otherwise, the changes look good for the drivers/hwtracing/coresight/*

Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>

On 26-01-21, 17:58, Uwe Kleine-König wrote:
> All amba drivers return 0 in their remove callback. Together with the
> driver core ignoring the return value anyhow, it doesn't make sense to
> return a value here.
> 
> Change the remove prototype to return void, which makes it explicit that
> returning an error value doesn't work as expected. This simplifies changing
> the core remove callback to return void, too.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> Acked-by: Mark Brown <broonie@kernel.org>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/amba/bus.c                                 | 5 ++---
>  drivers/char/hw_random/nomadik-rng.c               | 3 +--
>  drivers/dma/pl330.c                                | 3 +--

For dmaengine:

Acked-By: Vinod Koul <vkoul@kernel.org>

Hello,

On Tue, Jan 26, 2021 at 05:08:40PM +0000, Suzuki K Poulose wrote:
> On 1/26/21 4:58 PM, Uwe Kleine-König wrote:
> > All amba drivers return 0 in their remove callback. Together with the
> > driver core ignoring the return value anyhow, it doesn't make sense to
> > return a value here.
> > 
> > Change the remove prototype to return void, which makes it explicit that
> > returning an error value doesn't work as expected. This simplifies changing
> > the core remove callback to return void, too.
> > 
> > Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> > Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> > Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> > Acked-by: Mark Brown <broonie@kernel.org>
>  > Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Acked-by: Linus Walleij <linus.walleij@linaro.org>
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> 
> 
> >   drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 +---
> 
> You are most likely to have a conflict for the above file, with what is
> in coresight/next. It should be easy to resolve.

I'm surprised to see that the remove callback introduced in 2952ecf5df33
("coresight: etm4x: Refactor probing routine") has an __exit annotation.

With .suppress_bind_attrs = true you don't need a remove callback at
all. (And without .suppress_bind_attrs = true the remove callback must
have no __exit annotation.)

This make me looking at commit 45fe7befe0db ("coresight: remove broken
__exit annotations") by Arnd. Unless I miss something the better change
would have been to remove the unused remove callbacks instead of dropping
their __exit annotation?!

Anyhow, my conflict resolution looks as follows:

diff --cc drivers/hwtracing/coresight/coresight-etm4x-core.c
index 82787cba537d,473ab7480a36..000000000000
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@@ -1703,6 -1903,28 +1903,27 @@@ static int __exit etm4_remove_dev(struc
  	cpus_read_unlock();
  
  	coresight_unregister(drvdata->csdev);
+ 
+ 	return 0;
+ }
+ 
 -static int __exit etm4_remove_amba(struct amba_device *adev)
++static void __exit etm4_remove_amba(struct amba_device *adev)
+ {
+ 	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+ 
+ 	if (drvdata)
 -		return etm4_remove_dev(drvdata);
 -	return 0;
++		etm4_remove_dev(drvdata);
+ }
+ 
+ static int __exit etm4_remove_platform_dev(struct platform_device *pdev)
+ {
+ 	int ret = 0;
+ 	struct etmv4_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
+ 
+ 	if (drvdata)
+ 		ret = etm4_remove_dev(drvdata);
+ 	pm_runtime_disable(&pdev->dev);
+ 	return ret;
  }
  
  static const struct amba_id etm4_ids[] = {

If this series should make it in for 5.12 we probably need an immutable
branch between hwtracing and amba.

> Otherwise, the changes look good for the drivers/hwtracing/coresight/*
> 
> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Thanks
Uwe

On Tue, Jan 26, 2021 at 05:58:34PM +0100, Uwe Kleine-König wrote:
> All amba drivers return 0 in their remove callback. Together with the
> driver core ignoring the return value anyhow, it doesn't make sense to
> return a value here.
> 
> Change the remove prototype to return void, which makes it explicit that
> returning an error value doesn't work as expected. This simplifies changing
> the core remove callback to return void, too.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> Acked-by: Mark Brown <broonie@kernel.org>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

For watchdog:

Acked-by: Guenter Roeck <linux@roeck-us.net>

Guenter

> ---
>  drivers/amba/bus.c                                 | 5 ++---
>  drivers/char/hw_random/nomadik-rng.c               | 3 +--
>  drivers/dma/pl330.c                                | 3 +--
>  drivers/gpu/drm/pl111/pl111_drv.c                  | 4 +---
>  drivers/hwtracing/coresight/coresight-catu.c       | 3 +--
>  drivers/hwtracing/coresight/coresight-cpu-debug.c  | 4 +---
>  drivers/hwtracing/coresight/coresight-cti-core.c   | 4 +---
>  drivers/hwtracing/coresight/coresight-etb10.c      | 4 +---
>  drivers/hwtracing/coresight/coresight-etm3x-core.c | 4 +---
>  drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 +---
>  drivers/hwtracing/coresight/coresight-funnel.c     | 4 ++--
>  drivers/hwtracing/coresight/coresight-replicator.c | 4 ++--
>  drivers/hwtracing/coresight/coresight-stm.c        | 4 +---
>  drivers/hwtracing/coresight/coresight-tmc-core.c   | 4 +---
>  drivers/hwtracing/coresight/coresight-tpiu.c       | 4 +---
>  drivers/i2c/busses/i2c-nomadik.c                   | 4 +---
>  drivers/input/serio/ambakmi.c                      | 3 +--
>  drivers/memory/pl172.c                             | 4 +---
>  drivers/memory/pl353-smc.c                         | 4 +---
>  drivers/mmc/host/mmci.c                            | 4 +---
>  drivers/rtc/rtc-pl030.c                            | 4 +---
>  drivers/rtc/rtc-pl031.c                            | 4 +---
>  drivers/spi/spi-pl022.c                            | 5 ++---
>  drivers/tty/serial/amba-pl010.c                    | 4 +---
>  drivers/tty/serial/amba-pl011.c                    | 3 +--
>  drivers/vfio/platform/vfio_amba.c                  | 3 +--
>  drivers/video/fbdev/amba-clcd.c                    | 4 +---
>  drivers/watchdog/sp805_wdt.c                       | 4 +---
>  include/linux/amba/bus.h                           | 2 +-
>  sound/arm/aaci.c                                   | 4 +---
>  30 files changed, 34 insertions(+), 80 deletions(-)
> 
> diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
> index 8c4a42df47c6..48b5d4b4e889 100644
> --- a/drivers/amba/bus.c
> +++ b/drivers/amba/bus.c
> @@ -300,11 +300,10 @@ static int amba_remove(struct device *dev)
>  {
>  	struct amba_device *pcdev = to_amba_device(dev);
>  	struct amba_driver *drv = to_amba_driver(dev->driver);
> -	int ret = 0;
>  
>  	pm_runtime_get_sync(dev);
>  	if (drv->remove)
> -		ret = drv->remove(pcdev);
> +		drv->remove(pcdev);
>  	pm_runtime_put_noidle(dev);
>  
>  	/* Undo the runtime PM settings in amba_probe() */
> @@ -315,7 +314,7 @@ static int amba_remove(struct device *dev)
>  	amba_put_disable_pclk(pcdev);
>  	dev_pm_domain_detach(dev, true);
>  
> -	return ret;
> +	return 0;
>  }
>  
>  static void amba_shutdown(struct device *dev)
> diff --git a/drivers/char/hw_random/nomadik-rng.c b/drivers/char/hw_random/nomadik-rng.c
> index b0ded41eb865..67947a19aa22 100644
> --- a/drivers/char/hw_random/nomadik-rng.c
> +++ b/drivers/char/hw_random/nomadik-rng.c
> @@ -69,11 +69,10 @@ static int nmk_rng_probe(struct amba_device *dev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int nmk_rng_remove(struct amba_device *dev)
> +static void nmk_rng_remove(struct amba_device *dev)
>  {
>  	amba_release_regions(dev);
>  	clk_disable(rng_clk);
> -	return 0;
>  }
>  
>  static const struct amba_id nmk_rng_ids[] = {
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index bc0f66af0f11..fd8d2bc3be9f 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -3195,7 +3195,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int pl330_remove(struct amba_device *adev)
> +static void pl330_remove(struct amba_device *adev)
>  {
>  	struct pl330_dmac *pl330 = amba_get_drvdata(adev);
>  	struct dma_pl330_chan *pch, *_p;
> @@ -3235,7 +3235,6 @@ static int pl330_remove(struct amba_device *adev)
>  
>  	if (pl330->rstc)
>  		reset_control_assert(pl330->rstc);
> -	return 0;
>  }
>  
>  static const struct amba_id pl330_ids[] = {
> diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c
> index 40e6708fbbe2..1fb5eacefd2d 100644
> --- a/drivers/gpu/drm/pl111/pl111_drv.c
> +++ b/drivers/gpu/drm/pl111/pl111_drv.c
> @@ -320,7 +320,7 @@ static int pl111_amba_probe(struct amba_device *amba_dev,
>  	return ret;
>  }
>  
> -static int pl111_amba_remove(struct amba_device *amba_dev)
> +static void pl111_amba_remove(struct amba_device *amba_dev)
>  {
>  	struct device *dev = &amba_dev->dev;
>  	struct drm_device *drm = amba_get_drvdata(amba_dev);
> @@ -331,8 +331,6 @@ static int pl111_amba_remove(struct amba_device *amba_dev)
>  		drm_panel_bridge_remove(priv->bridge);
>  	drm_dev_put(drm);
>  	of_reserved_mem_device_release(dev);
> -
> -	return 0;
>  }
>  
>  /*
> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
> index a61313f320bd..8e19e8cdcce5 100644
> --- a/drivers/hwtracing/coresight/coresight-catu.c
> +++ b/drivers/hwtracing/coresight/coresight-catu.c
> @@ -567,12 +567,11 @@ static int catu_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int catu_remove(struct amba_device *adev)
> +static void catu_remove(struct amba_device *adev)
>  {
>  	struct catu_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
>  	coresight_unregister(drvdata->csdev);
> -	return 0;
>  }
>  
>  static struct amba_id catu_ids[] = {
> diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> index e1d232411d8d..2dcf13de751f 100644
> --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
> +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> @@ -627,7 +627,7 @@ static int debug_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int debug_remove(struct amba_device *adev)
> +static void debug_remove(struct amba_device *adev)
>  {
>  	struct device *dev = &adev->dev;
>  	struct debug_drvdata *drvdata = amba_get_drvdata(adev);
> @@ -642,8 +642,6 @@ static int debug_remove(struct amba_device *adev)
>  
>  	if (!--debug_count)
>  		debug_func_exit();
> -
> -	return 0;
>  }
>  
>  static const struct amba_cs_uci_id uci_id_debug[] = {
> diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
> index 61dbc1afd8da..30e48809ba00 100644
> --- a/drivers/hwtracing/coresight/coresight-cti-core.c
> +++ b/drivers/hwtracing/coresight/coresight-cti-core.c
> @@ -836,7 +836,7 @@ static void cti_device_release(struct device *dev)
>  	if (drvdata->csdev_release)
>  		drvdata->csdev_release(dev);
>  }
> -static int cti_remove(struct amba_device *adev)
> +static void cti_remove(struct amba_device *adev)
>  {
>  	struct cti_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
> @@ -845,8 +845,6 @@ static int cti_remove(struct amba_device *adev)
>  	mutex_unlock(&ect_mutex);
>  
>  	coresight_unregister(drvdata->csdev);
> -
> -	return 0;
>  }
>  
>  static int cti_probe(struct amba_device *adev, const struct amba_id *id)
> diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
> index 0cf6f0b947b6..51c801c05e5c 100644
> --- a/drivers/hwtracing/coresight/coresight-etb10.c
> +++ b/drivers/hwtracing/coresight/coresight-etb10.c
> @@ -803,7 +803,7 @@ static int etb_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int etb_remove(struct amba_device *adev)
> +static void etb_remove(struct amba_device *adev)
>  {
>  	struct etb_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
> @@ -814,8 +814,6 @@ static int etb_remove(struct amba_device *adev)
>  	 */
>  	misc_deregister(&drvdata->miscdev);
>  	coresight_unregister(drvdata->csdev);
> -
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> index 5bf5a5a4ce6d..683a69e88efd 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> @@ -909,7 +909,7 @@ static void clear_etmdrvdata(void *info)
>  	etmdrvdata[cpu] = NULL;
>  }
>  
> -static int etm_remove(struct amba_device *adev)
> +static void etm_remove(struct amba_device *adev)
>  {
>  	struct etm_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
> @@ -932,8 +932,6 @@ static int etm_remove(struct amba_device *adev)
>  	cpus_read_unlock();
>  
>  	coresight_unregister(drvdata->csdev);
> -
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index b20b6ff17cf6..82787cba537d 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -1680,7 +1680,7 @@ static void clear_etmdrvdata(void *info)
>  	etmdrvdata[cpu] = NULL;
>  }
>  
> -static int etm4_remove(struct amba_device *adev)
> +static void etm4_remove(struct amba_device *adev)
>  {
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
> @@ -1703,8 +1703,6 @@ static int etm4_remove(struct amba_device *adev)
>  	cpus_read_unlock();
>  
>  	coresight_unregister(drvdata->csdev);
> -
> -	return 0;
>  }
>  
>  static const struct amba_id etm4_ids[] = {
> diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
> index 071c723227db..01f8f9285168 100644
> --- a/drivers/hwtracing/coresight/coresight-funnel.c
> +++ b/drivers/hwtracing/coresight/coresight-funnel.c
> @@ -370,9 +370,9 @@ static int dynamic_funnel_probe(struct amba_device *adev,
>  	return funnel_probe(&adev->dev, &adev->res);
>  }
>  
> -static int dynamic_funnel_remove(struct amba_device *adev)
> +static void dynamic_funnel_remove(struct amba_device *adev)
>  {
> -	return funnel_remove(&adev->dev);
> +	funnel_remove(&adev->dev);
>  }
>  
>  static const struct amba_id dynamic_funnel_ids[] = {
> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
> index 7e2a2b7f503f..34fc2f6f3ea9 100644
> --- a/drivers/hwtracing/coresight/coresight-replicator.c
> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> @@ -388,9 +388,9 @@ static int dynamic_replicator_probe(struct amba_device *adev,
>  	return replicator_probe(&adev->dev, &adev->res);
>  }
>  
> -static int dynamic_replicator_remove(struct amba_device *adev)
> +static void dynamic_replicator_remove(struct amba_device *adev)
>  {
> -	return replicator_remove(&adev->dev);
> +	replicator_remove(&adev->dev);
>  }
>  
>  static const struct amba_id dynamic_replicator_ids[] = {
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
> index 99791773f682..423df0d30d9c 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -951,15 +951,13 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int stm_remove(struct amba_device *adev)
> +static void stm_remove(struct amba_device *adev)
>  {
>  	struct stm_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
>  	coresight_unregister(drvdata->csdev);
>  
>  	stm_unregister_device(&drvdata->stm);
> -
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index 8169dff5a9f6..e29b3914fc0f 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -559,7 +559,7 @@ static void tmc_shutdown(struct amba_device *adev)
>  	spin_unlock_irqrestore(&drvdata->spinlock, flags);
>  }
>  
> -static int tmc_remove(struct amba_device *adev)
> +static void tmc_remove(struct amba_device *adev)
>  {
>  	struct tmc_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
> @@ -570,8 +570,6 @@ static int tmc_remove(struct amba_device *adev)
>  	 */
>  	misc_deregister(&drvdata->miscdev);
>  	coresight_unregister(drvdata->csdev);
> -
> -	return 0;
>  }
>  
>  static const struct amba_id tmc_ids[] = {
> diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
> index d5dfee9ee556..f77c4b0ea4aa 100644
> --- a/drivers/hwtracing/coresight/coresight-tpiu.c
> +++ b/drivers/hwtracing/coresight/coresight-tpiu.c
> @@ -173,13 +173,11 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
>  	return PTR_ERR(drvdata->csdev);
>  }
>  
> -static int tpiu_remove(struct amba_device *adev)
> +static void tpiu_remove(struct amba_device *adev)
>  {
>  	struct tpiu_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>  
>  	coresight_unregister(drvdata->csdev);
> -
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM
> diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
> index d4b1b0865f67..a3363b20f168 100644
> --- a/drivers/i2c/busses/i2c-nomadik.c
> +++ b/drivers/i2c/busses/i2c-nomadik.c
> @@ -1055,7 +1055,7 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int nmk_i2c_remove(struct amba_device *adev)
> +static void nmk_i2c_remove(struct amba_device *adev)
>  {
>  	struct resource *res = &adev->res;
>  	struct nmk_i2c_dev *dev = amba_get_drvdata(adev);
> @@ -1068,8 +1068,6 @@ static int nmk_i2c_remove(struct amba_device *adev)
>  	i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
>  	clk_disable_unprepare(dev->clk);
>  	release_mem_region(res->start, resource_size(res));
> -
> -	return 0;
>  }
>  
>  static struct i2c_vendor_data vendor_stn8815 = {
> diff --git a/drivers/input/serio/ambakmi.c b/drivers/input/serio/ambakmi.c
> index ecdeca147ed7..4408245b61d2 100644
> --- a/drivers/input/serio/ambakmi.c
> +++ b/drivers/input/serio/ambakmi.c
> @@ -159,7 +159,7 @@ static int amba_kmi_probe(struct amba_device *dev,
>  	return ret;
>  }
>  
> -static int amba_kmi_remove(struct amba_device *dev)
> +static void amba_kmi_remove(struct amba_device *dev)
>  {
>  	struct amba_kmi_port *kmi = amba_get_drvdata(dev);
>  
> @@ -168,7 +168,6 @@ static int amba_kmi_remove(struct amba_device *dev)
>  	iounmap(kmi->base);
>  	kfree(kmi);
>  	amba_release_regions(dev);
> -	return 0;
>  }
>  
>  static int __maybe_unused amba_kmi_resume(struct device *dev)
> diff --git a/drivers/memory/pl172.c b/drivers/memory/pl172.c
> index 575fadbffa30..9eb8cc7de494 100644
> --- a/drivers/memory/pl172.c
> +++ b/drivers/memory/pl172.c
> @@ -273,14 +273,12 @@ static int pl172_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int pl172_remove(struct amba_device *adev)
> +static void pl172_remove(struct amba_device *adev)
>  {
>  	struct pl172_data *pl172 = amba_get_drvdata(adev);
>  
>  	clk_disable_unprepare(pl172->clk);
>  	amba_release_regions(adev);
> -
> -	return 0;
>  }
>  
>  static const struct amba_id pl172_ids[] = {
> diff --git a/drivers/memory/pl353-smc.c b/drivers/memory/pl353-smc.c
> index 73bd3023202f..3b5b1045edd9 100644
> --- a/drivers/memory/pl353-smc.c
> +++ b/drivers/memory/pl353-smc.c
> @@ -426,14 +426,12 @@ static int pl353_smc_probe(struct amba_device *adev, const struct amba_id *id)
>  	return err;
>  }
>  
> -static int pl353_smc_remove(struct amba_device *adev)
> +static void pl353_smc_remove(struct amba_device *adev)
>  {
>  	struct pl353_smc_data *pl353_smc = amba_get_drvdata(adev);
>  
>  	clk_disable_unprepare(pl353_smc->memclk);
>  	clk_disable_unprepare(pl353_smc->aclk);
> -
> -	return 0;
>  }
>  
>  static const struct amba_id pl353_ids[] = {
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index b5a41a7ce165..32f52d070bbd 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -2195,7 +2195,7 @@ static int mmci_probe(struct amba_device *dev,
>  	return ret;
>  }
>  
> -static int mmci_remove(struct amba_device *dev)
> +static void mmci_remove(struct amba_device *dev)
>  {
>  	struct mmc_host *mmc = amba_get_drvdata(dev);
>  
> @@ -2223,8 +2223,6 @@ static int mmci_remove(struct amba_device *dev)
>  		clk_disable_unprepare(host->clk);
>  		mmc_free_host(mmc);
>  	}
> -
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM
> diff --git a/drivers/rtc/rtc-pl030.c b/drivers/rtc/rtc-pl030.c
> index 5a880516f3e8..39038c0754ee 100644
> --- a/drivers/rtc/rtc-pl030.c
> +++ b/drivers/rtc/rtc-pl030.c
> @@ -137,7 +137,7 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int pl030_remove(struct amba_device *dev)
> +static void pl030_remove(struct amba_device *dev)
>  {
>  	struct pl030_rtc *rtc = amba_get_drvdata(dev);
>  
> @@ -146,8 +146,6 @@ static int pl030_remove(struct amba_device *dev)
>  	free_irq(dev->irq[0], rtc);
>  	iounmap(rtc->base);
>  	amba_release_regions(dev);
> -
> -	return 0;
>  }
>  
>  static struct amba_id pl030_ids[] = {
> diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c
> index 224bbf096262..620c8dc33647 100644
> --- a/drivers/rtc/rtc-pl031.c
> +++ b/drivers/rtc/rtc-pl031.c
> @@ -280,7 +280,7 @@ static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>  	return 0;
>  }
>  
> -static int pl031_remove(struct amba_device *adev)
> +static void pl031_remove(struct amba_device *adev)
>  {
>  	struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
>  
> @@ -289,8 +289,6 @@ static int pl031_remove(struct amba_device *adev)
>  	if (adev->irq[0])
>  		free_irq(adev->irq[0], ldata);
>  	amba_release_regions(adev);
> -
> -	return 0;
>  }
>  
>  static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
> diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
> index d1776fea287e..fd74ddfbb686 100644
> --- a/drivers/spi/spi-pl022.c
> +++ b/drivers/spi/spi-pl022.c
> @@ -2314,13 +2314,13 @@ static int pl022_probe(struct amba_device *adev, const struct amba_id *id)
>  	return status;
>  }
>  
> -static int
> +static void
>  pl022_remove(struct amba_device *adev)
>  {
>  	struct pl022 *pl022 = amba_get_drvdata(adev);
>  
>  	if (!pl022)
> -		return 0;
> +		return;
>  
>  	/*
>  	 * undo pm_runtime_put() in probe.  I assume that we're not
> @@ -2335,7 +2335,6 @@ pl022_remove(struct amba_device *adev)
>  	clk_disable_unprepare(pl022->clk);
>  	amba_release_regions(adev);
>  	tasklet_disable(&pl022->pump_transfers);
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM_SLEEP
> diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c
> index 3284f34e9dfe..3f96edfe569c 100644
> --- a/drivers/tty/serial/amba-pl010.c
> +++ b/drivers/tty/serial/amba-pl010.c
> @@ -754,7 +754,7 @@ static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int pl010_remove(struct amba_device *dev)
> +static void pl010_remove(struct amba_device *dev)
>  {
>  	struct uart_amba_port *uap = amba_get_drvdata(dev);
>  	int i;
> @@ -770,8 +770,6 @@ static int pl010_remove(struct amba_device *dev)
>  
>  	if (!busy)
>  		uart_unregister_driver(&amba_reg);
> -
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM_SLEEP
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index c255476cce28..4ead0c9048a8 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -2679,13 +2679,12 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
>  	return pl011_register_port(uap);
>  }
>  
> -static int pl011_remove(struct amba_device *dev)
> +static void pl011_remove(struct amba_device *dev)
>  {
>  	struct uart_amba_port *uap = amba_get_drvdata(dev);
>  
>  	uart_remove_one_port(&amba_reg, &uap->port);
>  	pl011_unregister_port(uap);
> -	return 0;
>  }
>  
>  #ifdef CONFIG_PM_SLEEP
> diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
> index 7b3ebf1558e1..3626c2150101 100644
> --- a/drivers/vfio/platform/vfio_amba.c
> +++ b/drivers/vfio/platform/vfio_amba.c
> @@ -71,14 +71,13 @@ static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int vfio_amba_remove(struct amba_device *adev)
> +static void vfio_amba_remove(struct amba_device *adev)
>  {
>  	struct vfio_platform_device *vdev =
>  		vfio_platform_remove_common(&adev->dev);
>  
>  	kfree(vdev->name);
>  	kfree(vdev);
> -	return 0;
>  }
>  
>  static const struct amba_id pl330_ids[] = {
> diff --git a/drivers/video/fbdev/amba-clcd.c b/drivers/video/fbdev/amba-clcd.c
> index b7682de412d8..33595cc4778e 100644
> --- a/drivers/video/fbdev/amba-clcd.c
> +++ b/drivers/video/fbdev/amba-clcd.c
> @@ -925,7 +925,7 @@ static int clcdfb_probe(struct amba_device *dev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int clcdfb_remove(struct amba_device *dev)
> +static void clcdfb_remove(struct amba_device *dev)
>  {
>  	struct clcd_fb *fb = amba_get_drvdata(dev);
>  
> @@ -942,8 +942,6 @@ static int clcdfb_remove(struct amba_device *dev)
>  	kfree(fb);
>  
>  	amba_release_regions(dev);
> -
> -	return 0;
>  }
>  
>  static const struct amba_id clcdfb_id_table[] = {
> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
> index 958dc32a708f..58a00e1ab23b 100644
> --- a/drivers/watchdog/sp805_wdt.c
> +++ b/drivers/watchdog/sp805_wdt.c
> @@ -305,14 +305,12 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>  	return ret;
>  }
>  
> -static int sp805_wdt_remove(struct amba_device *adev)
> +static void sp805_wdt_remove(struct amba_device *adev)
>  {
>  	struct sp805_wdt *wdt = amba_get_drvdata(adev);
>  
>  	watchdog_unregister_device(&wdt->wdd);
>  	watchdog_set_drvdata(&wdt->wdd, NULL);
> -
> -	return 0;
>  }
>  
>  static int __maybe_unused sp805_wdt_suspend(struct device *dev)
> diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
> index 0bbfd647f5c6..6cc93ab5b809 100644
> --- a/include/linux/amba/bus.h
> +++ b/include/linux/amba/bus.h
> @@ -76,7 +76,7 @@ struct amba_device {
>  struct amba_driver {
>  	struct device_driver	drv;
>  	int			(*probe)(struct amba_device *, const struct amba_id *);
> -	int			(*remove)(struct amba_device *);
> +	void			(*remove)(struct amba_device *);
>  	void			(*shutdown)(struct amba_device *);
>  	const struct amba_id	*id_table;
>  };
> diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c
> index a0996c47e58f..b326a5f5f0d5 100644
> --- a/sound/arm/aaci.c
> +++ b/sound/arm/aaci.c
> @@ -1055,7 +1055,7 @@ static int aaci_probe(struct amba_device *dev,
>  	return ret;
>  }
>  
> -static int aaci_remove(struct amba_device *dev)
> +static void aaci_remove(struct amba_device *dev)
>  {
>  	struct snd_card *card = amba_get_drvdata(dev);
>  
> @@ -1066,8 +1066,6 @@ static int aaci_remove(struct amba_device *dev)
>  		snd_card_free(card);
>  		amba_release_regions(dev);
>  	}
> -
> -	return 0;
>  }
>  
>  static struct amba_id aaci_ids[] = {
> -- 
> 2.29.2
>

On Tue, Jan 26, 2021 at 05:58:34PM +0100, Uwe Kleine-König wrote:
> All amba drivers return 0 in their remove callback. Together with the
> driver core ignoring the return value anyhow, it doesn't make sense to
> return a value here.
> 
> Change the remove prototype to return void, which makes it explicit that
> returning an error value doesn't work as expected. This simplifies changing
> the core remove callback to return void, too.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> Acked-by: Mark Brown <broonie@kernel.org>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C

On 1/26/21 6:58 PM, Uwe Kleine-König wrote:
> All amba drivers return 0 in their remove callback. Together with the
> driver core ignoring the return value anyhow, it doesn't make sense to
> return a value here.
> 
> Change the remove prototype to return void, which makes it explicit that
> returning an error value doesn't work as expected. This simplifies changing
> the core remove callback to return void, too.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> Acked-by: Mark Brown <broonie@kernel.org>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

For drivers/memory/pl172.c:

Acked-by: Vladimir Zapolskiy <vz@mleia.com>

--
Best wishes,
Vladimir