Re: [PATCH v8 1/3] fpga: mgr: Use standard dev_release for class driver

[Moritz Fischer <mdf@kernel.org>]

On Mon, Jun 28, 2021 at 03:49:46AM +0000, Wu, Hao wrote:
> > -----Original Message-----
> > From: Weight, Russell H <russell.h.weight@intel.com>
> > Sent: Friday, June 25, 2021 4:54 AM
> > To: mdf@kernel.org; linux-fpga@vger.kernel.org
> > Cc: trix@redhat.com; lgoncalv@redhat.com; Xu, Yilun <yilun.xu@intel.com>;
> > Wu, Hao <hao.wu@intel.com>; Gerlach, Matthew
> > <matthew.gerlach@intel.com>; Gong, Richard <richard.gong@intel.com>;
> > Weight, Russell H <russell.h.weight@intel.com>
> > Subject: [PATCH v8 1/3] fpga: mgr: Use standard dev_release for class driver
> > 
> > The FPGA manager class driver data structure is being treated as a
> > managed resource instead of using the standard dev_release call-back
> > function to release the class data structure. This change removes
> > the managed resource code for the freeing of the class data structure
> > and combines the create() and register() functions into a single
> > register() or register_simple() function.
> > 
> 
> Maybe register() and register_full() is better. it keeps the most used
> function name the same (and shorter than register_simple()). Just
> my 2 cents. Let's wait for review comments from Moritz to decide. : )

I like the register() and register_full() idea.
> 
> Thanks
> Hao
> 
> > The register() function accepts an info data structure to provide
> > flexibility in passing optional parameters. The register_simple()
> > function supports the current parameter list for users that don't
> > require the use of optional parameters.
> > 
> > The devm_fpga_mgr_register() function is retained, and the
> > devm_fpga_mgr_register_simple() function is added.
> > 
> > Signed-off-by: Russ Weight <russell.h.weight@intel.com>
> > Reviewed-by: Xu Yilun <yilun.xu@intel.com>
> > ---
> > v8:
> >   - Added reviewed-by tag.
> >   - Updated Documentation/driver-api/fpga/fpga-mgr.rst documentation.
> > v7:
> >   - Update the commit message to describe the new parameters for the
> >     *fpga_mgr_register() functions and to mention the
> >     *fpga_mgr_register_simple() functions.
> >   - Fix function prototypes in header file to rename dev to parent.
> >   - Make use of the PTR_ERR_OR_ZERO() macro when possible.
> >   - Some cleanup of comments.
> >   - Update function defintions/prototypes to apply const to the new info
> >     parameter.
> > v6:
> >   - Moved FPGA manager optional parameters out of the ops structure and
> >     back into the FPGA manager structure.
> >   - Changed fpga_mgr_register()/devm_fpga_mgr_register() parameters to
> >     accept an info data structure to provide flexibility in passing optional
> >     parameters.
> >   - Added fpga_mgr_register_simple()/devm_fpga_mgr_register_simple()
> >     functions to support current parameters for users that don't require
> >     the use of optional parameters.
> > v5:
> >   - Rebased on top of recently accepted patches.
> >   - Removed compat_id from the fpga_mgr_register() parameter list
> >     and added it to the fpga_manager_ops structure. This also required
> >     dynamically allocating the dfl-fme-ops structure in order to add
> >     the appropriate compat_id.
> > v4:
> >   - Added the compat_id parameter to fpga_mgr_register() and
> >     devm_fpga_mgr_register() to ensure that the compat_id is set before
> >     the device_register() call.
> > v3:
> >   - Cleaned up comment header for fpga_mgr_register()
> >   - Fix error return on ida_simple_get() failure
> > v2:
> >   - Restored devm_fpga_mgr_register() functionality, adapted for the combined
> >     create/register functionality.
> >   - All previous callers of devm_fpga_mgr_register() will continue to call
> >     devm_fpga_mgr_register().
> >   - replaced unnecessary ternary operators in return statements with standard
> >     if conditions.
> > ---
> >  Documentation/driver-api/fpga/fpga-mgr.rst |  39 ++--
> >  drivers/fpga/altera-cvp.c                  |  12 +-
> >  drivers/fpga/altera-pr-ip-core.c           |   8 +-
> >  drivers/fpga/altera-ps-spi.c               |   9 +-
> >  drivers/fpga/dfl-fme-mgr.c                 |  22 +--
> >  drivers/fpga/fpga-mgr.c                    | 214 +++++++++------------
> >  drivers/fpga/ice40-spi.c                   |   9 +-
> >  drivers/fpga/machxo2-spi.c                 |  10 +-
> >  drivers/fpga/socfpga-a10.c                 |  16 +-
> >  drivers/fpga/socfpga.c                     |   9 +-
> >  drivers/fpga/stratix10-soc.c               |  16 +-
> >  drivers/fpga/ts73xx-fpga.c                 |   9 +-
> >  drivers/fpga/xilinx-spi.c                  |  11 +-
> >  drivers/fpga/zynq-fpga.c                   |  16 +-
> >  drivers/fpga/zynqmp-fpga.c                 |   9 +-
> >  include/linux/fpga/fpga-mgr.h              |  62 ++++--
> >  16 files changed, 204 insertions(+), 267 deletions(-)
> > 
> > diff --git a/Documentation/driver-api/fpga/fpga-mgr.rst
> > b/Documentation/driver-api/fpga/fpga-mgr.rst
> > index 4d926b452cb3..fbb7f07cae9f 100644
> > --- a/Documentation/driver-api/fpga/fpga-mgr.rst
> > +++ b/Documentation/driver-api/fpga/fpga-mgr.rst
> > @@ -24,7 +24,8 @@ How to support a new FPGA device
> >  --------------------------------
> > 
> >  To add another FPGA manager, write a driver that implements a set of ops.  The
> > -probe function calls fpga_mgr_register(), such as::
> > +probe function calls devm_fpga_mgr_register() or
> > +devm_fpga_mgr_register_simple(), such as::
> > 
> >  	static const struct fpga_manager_ops socfpga_fpga_ops = {
> >  		.write_init = socfpga_fpga_ops_configure_init,
> > @@ -49,23 +50,9 @@ probe function calls fpga_mgr_register(), such as::
> >  		 * them in priv
> >  		 */
> > 
> > -		mgr = devm_fpga_mgr_create(dev, "Altera SOCFPGA FPGA
> > Manager",
> > -					   &socfpga_fpga_ops, priv);
> > -		if (!mgr)
> > -			return -ENOMEM;
> > -
> > -		platform_set_drvdata(pdev, mgr);
> > -
> > -		return fpga_mgr_register(mgr);
> > -	}
> > -
> > -	static int socfpga_fpga_remove(struct platform_device *pdev)
> > -	{
> > -		struct fpga_manager *mgr = platform_get_drvdata(pdev);
> > -
> > -		fpga_mgr_unregister(mgr);
> > -
> > -		return 0;
> > +		mgr = devm_fpga_mgr_register_simple(dev, "Altera SOCFPGA
> > FPGA Manager",
> > +						    &socfpga_fpga_ops, priv);
> > +		return PTR_ERR_OR_ZERO(mgr);
> >  	}
> > 
> > 
> > @@ -104,8 +91,10 @@ API for implementing a new FPGA Manager driver
> >  * ``fpga_mgr_states`` -  Values for :c:expr:`fpga_manager->state`.
> >  * struct fpga_manager -  the FPGA manager struct
> >  * struct fpga_manager_ops -  Low level FPGA manager driver ops
> > -* devm_fpga_mgr_create() -  Allocate and init a manager struct
> > -* fpga_mgr_register() -  Register an FPGA manager
> > +* fpga_mgr_register() -  Create and register an FPGA manager
> > +* fpga_mgr_register_simple() -  Create and register an FPGA manager
> > +* devm_fpga_mgr_register() -  Create and register an FPGA manager
> > +* devm_fpga_mgr_register_simple() -  Create and register an FPGA manager
> >  * fpga_mgr_unregister() -  Unregister an FPGA manager
> > 
> >  .. kernel-doc:: include/linux/fpga/fpga-mgr.h
> > @@ -118,10 +107,16 @@ API for implementing a new FPGA Manager driver
> >     :functions: fpga_manager_ops
> > 
> >  .. kernel-doc:: drivers/fpga/fpga-mgr.c
> > -   :functions: devm_fpga_mgr_create
> > +   :functions: fpga_mgr_register
> > 
> >  .. kernel-doc:: drivers/fpga/fpga-mgr.c
> > -   :functions: fpga_mgr_register
> > +   :functions: fpga_mgr_register_simple
> > +
> > +.. kernel-doc:: drivers/fpga/fpga-mgr.c
> > +   :functions: devm_fpga_mgr_register
> > +
> > +.. kernel-doc:: drivers/fpga/fpga-mgr.c
> > +   :functions: devm_fpga_mgr_register_simple
> > 
> >  .. kernel-doc:: drivers/fpga/fpga-mgr.c
> >     :functions: fpga_mgr_unregister
> > diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
> > index ccf4546eff29..ddf2ffe3f138 100644
> > --- a/drivers/fpga/altera-cvp.c
> > +++ b/drivers/fpga/altera-cvp.c
> > @@ -652,19 +652,15 @@ static int altera_cvp_probe(struct pci_dev *pdev,
> >  	snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s @%s",
> >  		 ALTERA_CVP_MGR_NAME, pci_name(pdev));
> > 
> > -	mgr = devm_fpga_mgr_create(&pdev->dev, conf->mgr_name,
> > -				   &altera_cvp_ops, conf);
> > -	if (!mgr) {
> > -		ret = -ENOMEM;
> > +	mgr = fpga_mgr_register_simple(&pdev->dev, conf->mgr_name,
> > +				       &altera_cvp_ops, conf);
> > +	if (IS_ERR(mgr)) {
> > +		ret = PTR_ERR(mgr);
> >  		goto err_unmap;
> >  	}
> > 
> >  	pci_set_drvdata(pdev, mgr);
> > 
> > -	ret = fpga_mgr_register(mgr);
> > -	if (ret)
> > -		goto err_unmap;
> > -
> >  	return 0;
> > 
> >  err_unmap:
> > diff --git a/drivers/fpga/altera-pr-ip-core.c b/drivers/fpga/altera-pr-ip-core.c
> > index dfdf21ed34c4..e0baf3392b67 100644
> > --- a/drivers/fpga/altera-pr-ip-core.c
> > +++ b/drivers/fpga/altera-pr-ip-core.c
> > @@ -191,11 +191,9 @@ int alt_pr_register(struct device *dev, void __iomem
> > *reg_base)
> >  		(val & ALT_PR_CSR_STATUS_MSK) >> ALT_PR_CSR_STATUS_SFT,
> >  		(int)(val & ALT_PR_CSR_PR_START));
> > 
> > -	mgr = devm_fpga_mgr_create(dev, dev_name(dev), &alt_pr_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(dev, dev_name(dev),
> > +					    &alt_pr_ops, priv);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> >  EXPORT_SYMBOL_GPL(alt_pr_register);
> > 
> > diff --git a/drivers/fpga/altera-ps-spi.c b/drivers/fpga/altera-ps-spi.c
> > index 23bfd4d1ad0f..f544de2a9f6b 100644
> > --- a/drivers/fpga/altera-ps-spi.c
> > +++ b/drivers/fpga/altera-ps-spi.c
> > @@ -302,12 +302,9 @@ static int altera_ps_probe(struct spi_device *spi)
> >  	snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s %s",
> >  		 dev_driver_string(&spi->dev), dev_name(&spi->dev));
> > 
> > -	mgr = devm_fpga_mgr_create(&spi->dev, conf->mgr_name,
> > -				   &altera_ps_ops, conf);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(&spi->dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(&spi->dev, conf->mgr_name,
> > +					    &altera_ps_ops, conf);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static const struct spi_device_id altera_ps_spi_ids[] = {
> > diff --git a/drivers/fpga/dfl-fme-mgr.c b/drivers/fpga/dfl-fme-mgr.c
> > index d5861d13b306..20b1cf3d957f 100644
> > --- a/drivers/fpga/dfl-fme-mgr.c
> > +++ b/drivers/fpga/dfl-fme-mgr.c
> > @@ -282,7 +282,7 @@ static void fme_mgr_get_compat_id(void __iomem
> > *fme_pr,
> >  static int fme_mgr_probe(struct platform_device *pdev)
> >  {
> >  	struct dfl_fme_mgr_pdata *pdata = dev_get_platdata(&pdev->dev);
> > -	struct fpga_compat_id *compat_id;
> > +	struct fpga_manager_info info = { 0 };
> >  	struct device *dev = &pdev->dev;
> >  	struct fme_mgr_priv *priv;
> >  	struct fpga_manager *mgr;
> > @@ -302,20 +302,16 @@ static int fme_mgr_probe(struct platform_device
> > *pdev)
> >  			return PTR_ERR(priv->ioaddr);
> >  	}
> > 
> > -	compat_id = devm_kzalloc(dev, sizeof(*compat_id), GFP_KERNEL);
> > -	if (!compat_id)
> > +	info.name = "DFL FME FPGA Manager";
> > +	info.mops = &fme_mgr_ops;
> > +	info.priv = priv;
> > +	info.compat_id = devm_kzalloc(dev, sizeof(*info.compat_id),
> > GFP_KERNEL);
> > +	if (!info.compat_id)
> >  		return -ENOMEM;
> > 
> > -	fme_mgr_get_compat_id(priv->ioaddr, compat_id);
> > -
> > -	mgr = devm_fpga_mgr_create(dev, "DFL FME FPGA Manager",
> > -				   &fme_mgr_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	mgr->compat_id = compat_id;
> > -
> > -	return devm_fpga_mgr_register(dev, mgr);
> > +	fme_mgr_get_compat_id(priv->ioaddr, info.compat_id);
> > +	mgr = devm_fpga_mgr_register(dev, &info);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static struct platform_driver fme_mgr_driver = {
> > diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> > index ecb4c3c795fa..6bd65a1b84fb 100644
> > --- a/drivers/fpga/fpga-mgr.c
> > +++ b/drivers/fpga/fpga-mgr.c
> > @@ -550,21 +550,19 @@ void fpga_mgr_unlock(struct fpga_manager *mgr)
> >  EXPORT_SYMBOL_GPL(fpga_mgr_unlock);
> > 
> >  /**
> > - * fpga_mgr_create - create and initialize an FPGA manager struct
> > + * fpga_mgr_register - create and register an FPGA Manager device
> >   * @parent:	fpga manager device from pdev
> > - * @name:	fpga manager name
> > - * @mops:	pointer to structure of fpga manager ops
> > - * @priv:	fpga manager private data
> > + * @info:	parameters for fpga manager
> >   *
> > - * The caller of this function is responsible for freeing the struct with
> > - * fpga_mgr_free().  Using devm_fpga_mgr_create() instead is recommended.
> > + * The caller of this function is responsible for calling fpga_mgr_unregister().
> > + * Using devm_fpga_mgr_register() instead is recommended.
> >   *
> > - * Return: pointer to struct fpga_manager or NULL
> > + * Return: pointer to struct fpga_manager pointer or ERR_PTR()
> >   */
> > -struct fpga_manager *fpga_mgr_create(struct device *parent, const char
> > *name,
> > -				     const struct fpga_manager_ops *mops,
> > -				     void *priv)
> > +struct fpga_manager *
> > +fpga_mgr_register(struct device *parent, const struct fpga_manager_info
> > *info)
> >  {
> > +	const struct fpga_manager_ops *mops = info->mops;
> >  	struct fpga_manager *mgr;
> >  	int id, ret;
> > 
> > @@ -572,29 +570,31 @@ struct fpga_manager *fpga_mgr_create(struct device
> > *parent, const char *name,
> >  	    !mops->write_init || (!mops->write && !mops->write_sg) ||
> >  	    (mops->write && mops->write_sg)) {
> >  		dev_err(parent, "Attempt to register without
> > fpga_manager_ops\n");
> > -		return NULL;
> > +		return ERR_PTR(-EINVAL);
> >  	}
> > 
> > -	if (!name || !strlen(name)) {
> > +	if (!info->name || !strlen(info->name)) {
> >  		dev_err(parent, "Attempt to register with no name!\n");
> > -		return NULL;
> > +		return ERR_PTR(-EINVAL);
> >  	}
> > 
> >  	mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
> >  	if (!mgr)
> > -		return NULL;
> > +		return ERR_PTR(-ENOMEM);
> > 
> >  	id = ida_simple_get(&fpga_mgr_ida, 0, 0, GFP_KERNEL);
> > -	if (id < 0)
> > +	if (id < 0) {
> > +		ret = id;
> >  		goto error_kfree;
> > +	}
> > 
> >  	mutex_init(&mgr->ref_mutex);
> > 
> > -	mgr->name = name;
> > -	mgr->mops = mops;
> > -	mgr->priv = priv;
> > +	mgr->name = info->name;
> > +	mgr->mops = info->mops;
> > +	mgr->priv = info->priv;
> > +	mgr->compat_id = info->compat_id;
> > 
> > -	device_initialize(&mgr->dev);
> >  	mgr->dev.class = fpga_mgr_class;
> >  	mgr->dev.groups = mops->groups;
> >  	mgr->dev.parent = parent;
> > @@ -605,6 +605,19 @@ struct fpga_manager *fpga_mgr_create(struct device
> > *parent, const char *name,
> >  	if (ret)
> >  		goto error_device;
> > 
> > +	/*
> > +	 * Initialize framework state by requesting low level driver read state
> > +	 * from device.  FPGA may be in reset mode or may have been
> > programmed
> > +	 * by bootloader or EEPROM.
> > +	 */
> > +	mgr->state = mgr->mops->state(mgr);
> > +
> > +	ret = device_register(&mgr->dev);
> > +	if (ret) {
> > +		put_device(&mgr->dev);
> > +		return ERR_PTR(ret);
> > +	}
> > +
> >  	return mgr;
> > 
> >  error_device:
> > @@ -612,98 +625,38 @@ struct fpga_manager *fpga_mgr_create(struct device
> > *parent, const char *name,
> >  error_kfree:
> >  	kfree(mgr);
> > 
> > -	return NULL;
> > -}
> > -EXPORT_SYMBOL_GPL(fpga_mgr_create);
> > -
> > -/**
> > - * fpga_mgr_free - free an FPGA manager created with fpga_mgr_create()
> > - * @mgr:	fpga manager struct
> > - */
> > -void fpga_mgr_free(struct fpga_manager *mgr)
> > -{
> > -	ida_simple_remove(&fpga_mgr_ida, mgr->dev.id);
> > -	kfree(mgr);
> > -}
> > -EXPORT_SYMBOL_GPL(fpga_mgr_free);
> > -
> > -static void devm_fpga_mgr_release(struct device *dev, void *res)
> > -{
> > -	struct fpga_mgr_devres *dr = res;
> > -
> > -	fpga_mgr_free(dr->mgr);
> > +	return ERR_PTR(ret);
> >  }
> > +EXPORT_SYMBOL_GPL(fpga_mgr_register);
> > 
> >  /**
> > - * devm_fpga_mgr_create - create and initialize a managed FPGA manager
> > struct
> > + * fpga_mgr_register_simple - create and register an FPGA Manager device
> >   * @parent:	fpga manager device from pdev
> >   * @name:	fpga manager name
> >   * @mops:	pointer to structure of fpga manager ops
> >   * @priv:	fpga manager private data
> >   *
> > - * This function is intended for use in an FPGA manager driver's probe function.
> > - * After the manager driver creates the manager struct with
> > - * devm_fpga_mgr_create(), it should register it with fpga_mgr_register().  The
> > - * manager driver's remove function should call fpga_mgr_unregister().  The
> > - * manager struct allocated with this function will be freed automatically on
> > - * driver detach.  This includes the case of a probe function returning error
> > - * before calling fpga_mgr_register(), the struct will still get cleaned up.
> > + * The caller of this function is responsible for calling fpga_mgr_unregister().
> > + * Using devm_fpga_mgr_register_simple() instead is recommended. This
> > simple
> > + * version of the register function should be sufficient for most users. The
> > + * fpga_mgr_register() function is available for users that need to pass
> > + * additional, optional parameters.
> >   *
> > - * Return: pointer to struct fpga_manager or NULL
> > + * Return: pointer to struct fpga_manager pointer or ERR_PTR()
> >   */
> > -struct fpga_manager *devm_fpga_mgr_create(struct device *parent, const
> > char *name,
> > -					  const struct fpga_manager_ops
> > *mops,
> > -					  void *priv)
> > +struct fpga_manager *
> > +fpga_mgr_register_simple(struct device *parent, const char *name,
> > +			 const struct fpga_manager_ops *mops, void *priv)
> >  {
> > -	struct fpga_mgr_devres *dr;
> > +	struct fpga_manager_info info = { 0 };
> > 
> > -	dr = devres_alloc(devm_fpga_mgr_release, sizeof(*dr), GFP_KERNEL);
> > -	if (!dr)
> > -		return NULL;
> > -
> > -	dr->mgr = fpga_mgr_create(parent, name, mops, priv);
> > -	if (!dr->mgr) {
> > -		devres_free(dr);
> > -		return NULL;
> > -	}
> > -
> > -	devres_add(parent, dr);
> > +	info.name = name;
> > +	info.mops = mops;
> > +	info.priv = priv;
> > 
> > -	return dr->mgr;
> > +	return fpga_mgr_register(parent, &info);
> >  }
> > -EXPORT_SYMBOL_GPL(devm_fpga_mgr_create);
> > -
> > -/**
> > - * fpga_mgr_register - register an FPGA manager
> > - * @mgr: fpga manager struct
> > - *
> > - * Return: 0 on success, negative error code otherwise.
> > - */
> > -int fpga_mgr_register(struct fpga_manager *mgr)
> > -{
> > -	int ret;
> > -
> > -	/*
> > -	 * Initialize framework state by requesting low level driver read state
> > -	 * from device.  FPGA may be in reset mode or may have been
> > programmed
> > -	 * by bootloader or EEPROM.
> > -	 */
> > -	mgr->state = mgr->mops->state(mgr);
> > -
> > -	ret = device_add(&mgr->dev);
> > -	if (ret)
> > -		goto error_device;
> > -
> > -	dev_info(&mgr->dev, "%s registered\n", mgr->name);
> > -
> > -	return 0;
> > -
> > -error_device:
> > -	ida_simple_remove(&fpga_mgr_ida, mgr->dev.id);
> > -
> > -	return ret;
> > -}
> > -EXPORT_SYMBOL_GPL(fpga_mgr_register);
> > +EXPORT_SYMBOL_GPL(fpga_mgr_register_simple);
> > 
> >  /**
> >   * fpga_mgr_unregister - unregister an FPGA manager
> > @@ -726,14 +679,6 @@ void fpga_mgr_unregister(struct fpga_manager *mgr)
> >  }
> >  EXPORT_SYMBOL_GPL(fpga_mgr_unregister);
> > 
> > -static int fpga_mgr_devres_match(struct device *dev, void *res,
> > -				 void *match_data)
> > -{
> > -	struct fpga_mgr_devres *dr = res;
> > -
> > -	return match_data == dr->mgr;
> > -}
> > -
> >  static void devm_fpga_mgr_unregister(struct device *dev, void *res)
> >  {
> >  	struct fpga_mgr_devres *dr = res;
> > @@ -743,44 +688,67 @@ static void devm_fpga_mgr_unregister(struct device
> > *dev, void *res)
> > 
> >  /**
> >   * devm_fpga_mgr_register - resource managed variant of fpga_mgr_register()
> > - * @dev: managing device for this FPGA manager
> > - * @mgr: fpga manager struct
> > + * @parent:	fpga manager device from pdev
> > + * @info:	parameters for fpga manager
> >   *
> >   * This is the devres variant of fpga_mgr_register() for which the unregister
> >   * function will be called automatically when the managing device is detached.
> >   */
> > -int devm_fpga_mgr_register(struct device *dev, struct fpga_manager *mgr)
> > +struct fpga_manager *
> > +devm_fpga_mgr_register(struct device *parent, const struct
> > fpga_manager_info *info)
> >  {
> >  	struct fpga_mgr_devres *dr;
> > -	int ret;
> > -
> > -	/*
> > -	 * Make sure that the struct fpga_manager * that is passed in is
> > -	 * managed itself.
> > -	 */
> > -	if (WARN_ON(!devres_find(dev, devm_fpga_mgr_release,
> > -				 fpga_mgr_devres_match, mgr)))
> > -		return -EINVAL;
> > +	struct fpga_manager *mgr;
> > 
> >  	dr = devres_alloc(devm_fpga_mgr_unregister, sizeof(*dr), GFP_KERNEL);
> >  	if (!dr)
> > -		return -ENOMEM;
> > +		return ERR_PTR(-ENOMEM);
> > 
> > -	ret = fpga_mgr_register(mgr);
> > -	if (ret) {
> > +	mgr = fpga_mgr_register(parent, info);
> > +	if (IS_ERR(mgr)) {
> >  		devres_free(dr);
> > -		return ret;
> > +		return mgr;
> >  	}
> > 
> >  	dr->mgr = mgr;
> > -	devres_add(dev, dr);
> > +	devres_add(parent, dr);
> > 
> > -	return 0;
> > +	return mgr;
> >  }
> >  EXPORT_SYMBOL_GPL(devm_fpga_mgr_register);
> > 
> > +/**
> > + * devm_fpga_mgr_register_simple - resource managed variant of
> > + *				   fpga_mgr_register_simple()
> > + * @parent:	fpga manager device from pdev
> > + * @name:	fpga manager name
> > + * @mops:	pointer to structure of fpga manager ops
> > + * @priv:	fpga manager private data
> > + *
> > + * This is the devres variant of fpga_mgr_register_simple() for which the
> > + * unregister function will be called automatically when the managing
> > + * device is detached.
> > + */
> > +struct fpga_manager *
> > +devm_fpga_mgr_register_simple(struct device *parent, const char *name,
> > +			      const struct fpga_manager_ops *mops, void *priv)
> > +{
> > +	struct fpga_manager_info info = { 0 };
> > +
> > +	info.name = name;
> > +	info.mops = mops;
> > +	info.priv = priv;
> > +
> > +	return devm_fpga_mgr_register(parent, &info);
> > +}
> > +EXPORT_SYMBOL_GPL(devm_fpga_mgr_register_simple);
> > +
> >  static void fpga_mgr_dev_release(struct device *dev)
> >  {
> > +	struct fpga_manager *mgr = to_fpga_manager(dev);
> > +
> > +	ida_simple_remove(&fpga_mgr_ida, mgr->dev.id);
> > +	kfree(mgr);
> >  }
> > 
> >  static int __init fpga_mgr_class_init(void)
> > diff --git a/drivers/fpga/ice40-spi.c b/drivers/fpga/ice40-spi.c
> > index 69dec5af23c3..448eb6f4e509 100644
> > --- a/drivers/fpga/ice40-spi.c
> > +++ b/drivers/fpga/ice40-spi.c
> > @@ -178,12 +178,9 @@ static int ice40_fpga_probe(struct spi_device *spi)
> >  		return ret;
> >  	}
> > 
> > -	mgr = devm_fpga_mgr_create(dev, "Lattice iCE40 FPGA Manager",
> > -				   &ice40_fpga_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(dev, "Lattice iCE40 FPGA
> > Manager",
> > +					    &ice40_fpga_ops, priv);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static const struct of_device_id ice40_fpga_of_match[] = {
> > diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
> > index 114a64d2b7a4..77be11155402 100644
> > --- a/drivers/fpga/machxo2-spi.c
> > +++ b/drivers/fpga/machxo2-spi.c
> > @@ -366,12 +366,10 @@ static int machxo2_spi_probe(struct spi_device *spi)
> >  		return -EINVAL;
> >  	}
> > 
> > -	mgr = devm_fpga_mgr_create(dev, "Lattice MachXO2 SPI FPGA
> > Manager",
> > -				   &machxo2_ops, spi);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(dev,
> > +					    "Lattice MachXO2 SPI FPGA
> > Manager",
> > +					    &machxo2_ops, spi);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static const struct of_device_id of_match[] = {
> > diff --git a/drivers/fpga/socfpga-a10.c b/drivers/fpga/socfpga-a10.c
> > index 573d88bdf730..5ffefaa3eb07 100644
> > --- a/drivers/fpga/socfpga-a10.c
> > +++ b/drivers/fpga/socfpga-a10.c
> > @@ -508,19 +508,15 @@ static int socfpga_a10_fpga_probe(struct
> > platform_device *pdev)
> >  		return -EBUSY;
> >  	}
> > 
> > -	mgr = devm_fpga_mgr_create(dev, "SoCFPGA Arria10 FPGA Manager",
> > -				   &socfpga_a10_fpga_mgr_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	platform_set_drvdata(pdev, mgr);
> > -
> > -	ret = fpga_mgr_register(mgr);
> > -	if (ret) {
> > +	mgr = fpga_mgr_register_simple(dev, "SoCFPGA Arria10 FPGA Manager",
> > +				       &socfpga_a10_fpga_mgr_ops, priv);
> > +	if (IS_ERR(mgr)) {
> >  		clk_disable_unprepare(priv->clk);
> > -		return ret;
> > +		return PTR_ERR(mgr);
> >  	}
> > 
> > +	platform_set_drvdata(pdev, mgr);
> > +
> >  	return 0;
> >  }
> > 
> > diff --git a/drivers/fpga/socfpga.c b/drivers/fpga/socfpga.c
> > index 1f467173fc1f..9280db4364d4 100644
> > --- a/drivers/fpga/socfpga.c
> > +++ b/drivers/fpga/socfpga.c
> > @@ -571,12 +571,9 @@ static int socfpga_fpga_probe(struct platform_device
> > *pdev)
> >  	if (ret)
> >  		return ret;
> > 
> > -	mgr = devm_fpga_mgr_create(dev, "Altera SOCFPGA FPGA Manager",
> > -				   &socfpga_fpga_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(dev, "Altera SOCFPGA FPGA
> > Manager",
> > +					    &socfpga_fpga_ops, priv);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  #ifdef CONFIG_OF
> > diff --git a/drivers/fpga/stratix10-soc.c b/drivers/fpga/stratix10-soc.c
> > index a2cea500f7cc..fb84d88d4ce9 100644
> > --- a/drivers/fpga/stratix10-soc.c
> > +++ b/drivers/fpga/stratix10-soc.c
> > @@ -425,18 +425,11 @@ static int s10_probe(struct platform_device *pdev)
> > 
> >  	init_completion(&priv->status_return_completion);
> > 
> > -	mgr = fpga_mgr_create(dev, "Stratix10 SOC FPGA Manager",
> > -			      &s10_ops, priv);
> > -	if (!mgr) {
> > -		dev_err(dev, "unable to create FPGA manager\n");
> > -		ret = -ENOMEM;
> > -		goto probe_err;
> > -	}
> > -
> > -	ret = fpga_mgr_register(mgr);
> > -	if (ret) {
> > +	mgr = fpga_mgr_register_simple(dev, "Stratix10 SOC FPGA Manager",
> > +				       &s10_ops, priv);
> > +	if (IS_ERR(mgr)) {
> >  		dev_err(dev, "unable to register FPGA manager\n");
> > -		fpga_mgr_free(mgr);
> > +		ret = PTR_ERR(mgr);
> >  		goto probe_err;
> >  	}
> > 
> > @@ -454,7 +447,6 @@ static int s10_remove(struct platform_device *pdev)
> >  	struct s10_priv *priv = mgr->priv;
> > 
> >  	fpga_mgr_unregister(mgr);
> > -	fpga_mgr_free(mgr);
> >  	stratix10_svc_free_channel(priv->chan);
> > 
> >  	return 0;
> > diff --git a/drivers/fpga/ts73xx-fpga.c b/drivers/fpga/ts73xx-fpga.c
> > index 101f016c6ed8..009d5cfa1074 100644
> > --- a/drivers/fpga/ts73xx-fpga.c
> > +++ b/drivers/fpga/ts73xx-fpga.c
> > @@ -122,12 +122,9 @@ static int ts73xx_fpga_probe(struct platform_device
> > *pdev)
> >  	if (IS_ERR(priv->io_base))
> >  		return PTR_ERR(priv->io_base);
> > 
> > -	mgr = devm_fpga_mgr_create(kdev, "TS-73xx FPGA Manager",
> > -				   &ts73xx_fpga_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(kdev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(kdev, "TS-73xx FPGA Manager",
> > +					    &ts73xx_fpga_ops, priv);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static struct platform_driver ts73xx_fpga_driver = {
> > diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
> > index fee4d0abf6bf..6f568a757cf2 100644
> > --- a/drivers/fpga/xilinx-spi.c
> > +++ b/drivers/fpga/xilinx-spi.c
> > @@ -247,13 +247,10 @@ static int xilinx_spi_probe(struct spi_device *spi)
> >  		return dev_err_probe(&spi->dev, PTR_ERR(conf->done),
> >  				     "Failed to get DONE gpio\n");
> > 
> > -	mgr = devm_fpga_mgr_create(&spi->dev,
> > -				   "Xilinx Slave Serial FPGA Manager",
> > -				   &xilinx_spi_ops, conf);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(&spi->dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(&spi->dev,
> > +					    "Xilinx Slave Serial FPGA Manager",
> > +					    &xilinx_spi_ops, conf);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static const struct of_device_id xlnx_spi_of_match[] = {
> > diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
> > index 9b75bd4f93d8..a3de365aadc6 100644
> > --- a/drivers/fpga/zynq-fpga.c
> > +++ b/drivers/fpga/zynq-fpga.c
> > @@ -609,20 +609,16 @@ static int zynq_fpga_probe(struct platform_device
> > *pdev)
> > 
> >  	clk_disable(priv->clk);
> > 
> > -	mgr = devm_fpga_mgr_create(dev, "Xilinx Zynq FPGA Manager",
> > -				   &zynq_fpga_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	platform_set_drvdata(pdev, mgr);
> > -
> > -	err = fpga_mgr_register(mgr);
> > -	if (err) {
> > +	mgr = fpga_mgr_register_simple(dev, "Xilinx Zynq FPGA Manager",
> > +				       &zynq_fpga_ops, priv);
> > +	if (IS_ERR(mgr)) {
> >  		dev_err(dev, "unable to register FPGA manager\n");
> >  		clk_unprepare(priv->clk);
> > -		return err;
> > +		return PTR_ERR(mgr);
> >  	}
> > 
> > +	platform_set_drvdata(pdev, mgr);
> > +
> >  	return 0;
> >  }
> > 
> > diff --git a/drivers/fpga/zynqmp-fpga.c b/drivers/fpga/zynqmp-fpga.c
> > index 125743c9797f..53a7b36f61e8 100644
> > --- a/drivers/fpga/zynqmp-fpga.c
> > +++ b/drivers/fpga/zynqmp-fpga.c
> > @@ -102,12 +102,9 @@ static int zynqmp_fpga_probe(struct platform_device
> > *pdev)
> > 
> >  	priv->dev = dev;
> > 
> > -	mgr = devm_fpga_mgr_create(dev, "Xilinx ZynqMP FPGA Manager",
> > -				   &zynqmp_fpga_ops, priv);
> > -	if (!mgr)
> > -		return -ENOMEM;
> > -
> > -	return devm_fpga_mgr_register(dev, mgr);
> > +	mgr = devm_fpga_mgr_register_simple(dev, "Xilinx ZynqMP FPGA
> > Manager",
> > +					    &zynqmp_fpga_ops, priv);
> > +	return PTR_ERR_OR_ZERO(mgr);
> >  }
> > 
> >  static const struct of_device_id zynqmp_fpga_of_match[] = {
> > diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> > index 474c1f506307..9efe55be93bc 100644
> > --- a/include/linux/fpga/fpga-mgr.h
> > +++ b/include/linux/fpga/fpga-mgr.h
> > @@ -105,6 +105,36 @@ struct fpga_image_info {
> >  #endif
> >  };
> > 
> > +/**
> > + * struct fpga_compat_id - id for compatibility check
> > + *
> > + * @id_h: high 64bit of the compat_id
> > + * @id_l: low 64bit of the compat_id
> > + */
> > +struct fpga_compat_id {
> > +	u64 id_h;
> > +	u64 id_l;
> > +};
> > +
> > +/**
> > + * struct fpga_manager_info - collection of parameters for an FPGA Manager
> > + * @name: fpga manager name
> > + * @compat_id: FPGA manager id for compatibility check.
> > + * @mops: pointer to structure of fpga manager ops
> > + * @priv: fpga manager private data
> > + *
> > + * fpga_manager_info contains parameters for the register function. These
> > + * are separated into an info structure because they some are optional
> > + * others could be added to in the future. The info structure facilitates
> > + * maintaining a stable API.
> > + */
> > +struct fpga_manager_info {
> > +	const char *name;
> > +	struct fpga_compat_id *compat_id;
> > +	const struct fpga_manager_ops *mops;
> > +	void *priv;
> > +};
> > +
> >  /**
> >   * struct fpga_manager_ops - ops for low level fpga manager drivers
> >   * @initial_header_size: Maximum number of bytes that should be passed into
> > write_init
> > @@ -143,17 +173,6 @@ struct fpga_manager_ops {
> >  #define FPGA_MGR_STATUS_IP_PROTOCOL_ERR		BIT(3)
> >  #define FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR	BIT(4)
> > 
> > -/**
> > - * struct fpga_compat_id - id for compatibility check
> > - *
> > - * @id_h: high 64bit of the compat_id
> > - * @id_l: low 64bit of the compat_id
> > - */
> > -struct fpga_compat_id {
> > -	u64 id_h;
> > -	u64 id_l;
> > -};
> > -
> >  /**
> >   * struct fpga_manager - fpga manager structure
> >   * @name: name of low level fpga manager
> > @@ -191,17 +210,18 @@ struct fpga_manager *fpga_mgr_get(struct device
> > *dev);
> > 
> >  void fpga_mgr_put(struct fpga_manager *mgr);
> > 
> > -struct fpga_manager *fpga_mgr_create(struct device *dev, const char *name,
> > -				     const struct fpga_manager_ops *mops,
> > -				     void *priv);
> > -void fpga_mgr_free(struct fpga_manager *mgr);
> > -int fpga_mgr_register(struct fpga_manager *mgr);
> > -void fpga_mgr_unregister(struct fpga_manager *mgr);
> > +struct fpga_manager *
> > +fpga_mgr_register(struct device *parent, const struct fpga_manager_info
> > *info);
> > 
> > -int devm_fpga_mgr_register(struct device *dev, struct fpga_manager *mgr);
> > +struct fpga_manager *
> > +fpga_mgr_register_simple(struct device *parent, const char *name,
> > +			 const struct fpga_manager_ops *mops, void *priv);
> > +void fpga_mgr_unregister(struct fpga_manager *mgr);
> > 
> > -struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char
> > *name,
> > -					  const struct fpga_manager_ops
> > *mops,
> > -					  void *priv);
> > +struct fpga_manager *
> > +devm_fpga_mgr_register(struct device *parent, const struct
> > fpga_manager_info *info);
> > +struct fpga_manager *
> > +devm_fpga_mgr_register_simple(struct device *parent, const char *name,
> > +			      const struct fpga_manager_ops *mops, void *priv);
> > 
> >  #endif /*_LINUX_FPGA_MGR_H */
> > --
> > 2.25.1
> 

- Moritz