extcon: usbc-tusb320: unregister typec port on driver removal

From: Alvin Šipraga <alsi@bang-olufsen.dk>

The driver can register a typec port if suitable firmware properties are
present. But if the driver is removed through sysfs unbind, rmmod or
similar, then it does not clean up after itself and the typec port
device remains registered. This can be seen in sysfs, where stale typec
ports get left over in /sys/class/typec.

In order to fix this we have to add an i2c_driver remove function and
call typec_unregister_port(), which is a no-op in the case where no
typec port is created and the pointer remains NULL.

In the process we should also put the fwnode_handle when the typec port
isn't registered anymore, including if an error occurs during probe. The
typec subsystem does not increase or decrease the reference counter for
us, so we track it in the driver's private data.

Note that the conditional check on TYPEC_PWR_MODE_PD was removed in the
probe path because a call to tusb320_set_adv_pwr_mode() will perform an
even more robust validation immediately after, hence there is no
functional change here.

Fixes: bf7571c00dca ("extcon: usbc-tusb320: Add USB TYPE-C support")
Cc: stable@vger.kernel.org
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
---
 drivers/extcon/extcon-usbc-tusb320.c | 42 ++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 8 deletions(-)

Hi Alvin,

I love your patch! Perhaps something to improve:

[auto build test WARNING on chanwoo-extcon/extcon-next]
[also build test WARNING on linus/master v6.3-rc2 next-20230310]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alvin-ipraga/extcon-usbc-tusb320-unregister-typec-port-on-driver-removal/20230313-210245
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/extcon.git extcon-next
patch link:    https://lore.kernel.org/r/20230313130105.4183296-1-alvin%40pqrs.dk
patch subject: [PATCH] extcon: usbc-tusb320: unregister typec port on driver removal
config: i386-randconfig-a013-20230313 (https://download.01.org/0day-ci/archive/20230314/202303141316.EltVGG8V-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/fe414069d19f6d59c7c34f820459f4114e2de136
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Alvin-ipraga/extcon-usbc-tusb320-unregister-typec-port-on-driver-removal/20230313-210245
        git checkout fe414069d19f6d59c7c34f820459f4114e2de136
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/extcon/ drivers/media/common/videobuf2/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303141316.EltVGG8V-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/extcon/extcon-usbc-tusb320.c:429:8: warning: expression result unused [-Wunused-value]
           priv->connector_fwnode;
           ~~~~  ^~~~~~~~~~~~~~~~
   1 warning generated.


vim +429 drivers/extcon/extcon-usbc-tusb320.c

   379	
   380	static int tusb320_typec_probe(struct i2c_client *client,
   381				       struct tusb320_priv *priv)
   382	{
   383		struct fwnode_handle *connector;
   384		const char *cap_str;
   385		int ret;
   386	
   387		/* The Type-C connector is optional, for backward compatibility. */
   388		connector = device_get_named_child_node(&client->dev, "connector");
   389		if (!connector)
   390			return 0;
   391	
   392		/* Type-C connector found. */
   393		ret = typec_get_fw_cap(&priv->cap, connector);
   394		if (ret)
   395			goto err_put;
   396	
   397		priv->port_type = priv->cap.type;
   398	
   399		/* This goes into register 0x8 field CURRENT_MODE_ADVERTISE */
   400		ret = fwnode_property_read_string(connector, "typec-power-opmode", &cap_str);
   401		if (ret)
   402			goto err_put;
   403	
   404		ret = typec_find_pwr_opmode(cap_str);
   405		if (ret < 0)
   406			goto err_put;
   407	
   408		priv->pwr_opmode = ret;
   409	
   410		/* Initialize the hardware with the devicetree settings. */
   411		ret = tusb320_set_adv_pwr_mode(priv);
   412		if (ret)
   413			goto err_put;
   414	
   415		priv->cap.revision		= USB_TYPEC_REV_1_1;
   416		priv->cap.accessory[0]		= TYPEC_ACCESSORY_AUDIO;
   417		priv->cap.accessory[1]		= TYPEC_ACCESSORY_DEBUG;
   418		priv->cap.orientation_aware	= true;
   419		priv->cap.driver_data		= priv;
   420		priv->cap.ops			= &tusb320_typec_ops;
   421		priv->cap.fwnode		= connector;
   422	
   423		priv->port = typec_register_port(&client->dev, &priv->cap);
   424		if (IS_ERR(priv->port)) {
   425			ret = PTR_ERR(priv->port);
   426			goto err_put;
   427		}
   428	
 > 429		priv->connector_fwnode;
   430	
   431		return 0;
   432	
   433	err_put:
   434		fwnode_handle_put(connector);
   435	
   436		return ret;
   437	}
   438