[PATCH 00/13] Make some spi device drivers return zero in .remove()

[PATCH 00/13] Make some spi device drivers return zero in .remove()

[Uwe Kleine-König]

Hello,

this series is part of my new quest to make spi remove callbacks return
void. Today they return an int, but the only result of returning a
non-zero value is a warning message. So it's a bad idea to return an
error code in the expectation that not freeing some resources is ok
then. The same holds true for i2c and platform devices which benefit en
passant for a few drivers.

The patches in this series address some of the spi drivers that might
return non-zero and adapt them accordingly to return zero instead. For
most drivers it's just about not hiding the fact that they already
return zero.

Given that there are quite some more patches of this type to create
before I can change the spi remove callback, I suggest the respecive
subsystem maintainers pick up these patches. There are no
interdependencies in this series.

Uwe Kleine-König (13):
  drm/panel: s6e63m0: Make s6e63m0_remove() return void
  hwmon: adt7x10: Make adt7x10_remove() return void
  hwmon: max31722: Warn about failure to put device in stand-by in
    .remove()
  input: adxl34xx: Make adxl34x_remove() return void
  input: touchscreen: tsc200x: Make tsc200x_remove() return void
  media: cxd2880: Eliminate dead code
  mfd: mc13xxx: Make mc13xxx_common_exit() return void
  mfd: stmpe: Make stmpe_remove() return void
  mfd: tps65912: Make tps65912_device_exit() return void
  serial: max310x: Make max310x_remove() return void
  serial: sc16is7xx: Make sc16is7xx_remove() return void
  staging: fbtft: Make fbtft_remove_common() return void
  tpm: st33zp24: Make st33zp24_remove() return void

 drivers/char/tpm/st33zp24/i2c.c                   |  5 +----
 drivers/char/tpm/st33zp24/spi.c                   |  5 +----
 drivers/char/tpm/st33zp24/st33zp24.c              |  3 +--
 drivers/char/tpm/st33zp24/st33zp24.h              |  2 +-
 drivers/gpu/drm/panel/panel-samsung-s6e63m0-dsi.c |  3 ++-
 drivers/gpu/drm/panel/panel-samsung-s6e63m0-spi.c |  3 ++-
 drivers/gpu/drm/panel/panel-samsung-s6e63m0.c     |  4 +---
 drivers/gpu/drm/panel/panel-samsung-s6e63m0.h     |  2 +-
 drivers/hwmon/adt7310.c                           |  3 ++-
 drivers/hwmon/adt7410.c                           |  3 ++-
 drivers/hwmon/adt7x10.c                           |  3 +--
 drivers/hwmon/adt7x10.h                           |  2 +-
 drivers/hwmon/max31722.c                          |  8 +++++++-
 drivers/input/misc/adxl34x-i2c.c                  |  4 +++-
 drivers/input/misc/adxl34x-spi.c                  |  4 +++-
 drivers/input/misc/adxl34x.c                      |  4 +---
 drivers/input/misc/adxl34x.h                      |  2 +-
 drivers/input/touchscreen/tsc2004.c               |  4 +++-
 drivers/input/touchscreen/tsc2005.c               |  4 +++-
 drivers/input/touchscreen/tsc200x-core.c          |  4 +---
 drivers/input/touchscreen/tsc200x-core.h          |  2 +-
 drivers/media/spi/cxd2880-spi.c                   | 13 +------------
 drivers/mfd/mc13xxx-core.c                        |  4 +---
 drivers/mfd/mc13xxx-i2c.c                         |  3 ++-
 drivers/mfd/mc13xxx-spi.c                         |  3 ++-
 drivers/mfd/mc13xxx.h                             |  2 +-
 drivers/mfd/stmpe-i2c.c                           |  4 +++-
 drivers/mfd/stmpe-spi.c                           |  4 +++-
 drivers/mfd/stmpe.c                               |  4 +---
 drivers/mfd/stmpe.h                               |  2 +-
 drivers/mfd/tps65912-core.c                       |  4 +---
 drivers/mfd/tps65912-i2c.c                        |  4 +++-
 drivers/mfd/tps65912-spi.c                        |  4 +++-
 drivers/staging/fbtft/fbtft-core.c                |  8 +-------
 drivers/staging/fbtft/fbtft.h                     |  6 ++++--
 drivers/tty/serial/max310x.c                      |  7 +++----
 drivers/tty/serial/sc16is7xx.c                    | 10 +++++++---
 include/linux/mfd/tps65912.h                      |  2 +-
 38 files changed, 77 insertions(+), 81 deletions(-)


base-commit: 9e1ff307c779ce1f0f810c7ecce3d95bbae40896
-- 
2.30.2

[PATCH 06/13] media: cxd2880: Eliminate dead code

[Uwe Kleine-König]

An spi remove callback is never called with an spi_device pointer that
is NULL. Also it is only called for devices that probed successfully. As
cxd2880_spi_probe() always sets driver data, spi_get_drvdata() cannot be
NULL.

Also the return value of spi remove callbacks is ignored anyway and not
freeing resources in .remove() is a bad idea.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/media/spi/cxd2880-spi.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/media/spi/cxd2880-spi.c b/drivers/media/spi/cxd2880-spi.c
index b91a1e845b97..67cacf29a61e 100644
--- a/drivers/media/spi/cxd2880-spi.c
+++ b/drivers/media/spi/cxd2880-spi.c
@@ -628,19 +628,8 @@ cxd2880_spi_probe(struct spi_device *spi)
 static int
 cxd2880_spi_remove(struct spi_device *spi)
 {
-	struct cxd2880_dvb_spi *dvb_spi;
+	struct cxd2880_dvb_spi *dvb_spi = spi_get_drvdata(spi);
 
-	if (!spi) {
-		pr_err("invalid arg\n");
-		return -EINVAL;
-	}
-
-	dvb_spi = spi_get_drvdata(spi);
-
-	if (!dvb_spi) {
-		pr_err("failed\n");
-		return -EINVAL;
-	}
 	dvb_spi->demux.dmx.remove_frontend(&dvb_spi->demux.dmx,
 					   &dvb_spi->dmx_fe);
 	dvb_dmxdev_release(&dvb_spi->dmxdev);
-- 
2.30.2

Re: [PATCH 00/13] Make some spi device drivers return zero in .remove()

[Uwe Kleine-König]

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Hello,

On Mon, Oct 11, 2021 at 03:27:41PM +0200, Uwe Kleine-König wrote:
> this series is part of my new quest to make spi remove callbacks return
> void. Today they return an int, but the only result of returning a
> non-zero value is a warning message. So it's a bad idea to return an
> error code in the expectation that not freeing some resources is ok
> then. The same holds true for i2c and platform devices which benefit en
> passant for a few drivers.
> 
> The patches in this series address some of the spi drivers that might
> return non-zero and adapt them accordingly to return zero instead. For
> most drivers it's just about not hiding the fact that they already
> return zero.
> 
> Given that there are quite some more patches of this type to create
> before I can change the spi remove callback, I suggest the respecive
> subsystem maintainers pick up these patches. There are no
> interdependencies in this series.
> 
> Uwe Kleine-König (13):
>   drm/panel: s6e63m0: Make s6e63m0_remove() return void
>   hwmon: adt7x10: Make adt7x10_remove() return void
>   hwmon: max31722: Warn about failure to put device in stand-by in
>     .remove()
>   input: adxl34xx: Make adxl34x_remove() return void
>   input: touchscreen: tsc200x: Make tsc200x_remove() return void
>   media: cxd2880: Eliminate dead code
>   mfd: mc13xxx: Make mc13xxx_common_exit() return void
>   mfd: stmpe: Make stmpe_remove() return void
>   mfd: tps65912: Make tps65912_device_exit() return void
>   serial: max310x: Make max310x_remove() return void
>   serial: sc16is7xx: Make sc16is7xx_remove() return void
>   staging: fbtft: Make fbtft_remove_common() return void
>   tpm: st33zp24: Make st33zp24_remove() return void

I thought I would be a good enough programmer to not need build tests.
Obviously I was wrong and introduced build problems with the following
patches:

	input: touchscreen: tsc200x: Make tsc200x_remove() return void
	mfd: mc13xxx: Make mc13xxx_common_exit() return void
	serial: max310x: Make max310x_remove() return void
	serial: sc16is7xx: Make sc16is7xx_remove() return void

Please don't apply these (unless you also fix the trivial problems in
them). I will prepare a v2 soon.

Best regards and sorry for the inconvenience,
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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