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

[Russ Weight <russell.h.weight@intel.com>]

On 6/27/21 8:49 PM, 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. : )

OK - I'm making this changes for the next version.

- Russ

>
> 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