| Message ID | 19d37e48-0b64-b33c-993a-a1cae39efb54@gmail.com |
|---|---|
| State | Superseded |
| Delegated to: | Bartosz Golaszewski |
| Headers | show |
| Series | i2c: introduce devm_i2c_new_dummy and use it in at24 driver | expand |
2017-12-05 20:44 GMT+01:00 Heiner Kallweit <hkallweit1@gmail.com>: > i2c_new_dummy is typically called from the probe function of the > driver for the primary i2c client. It requires calls to > i2c_unregister_device in the error path of the probe function and > in the remove function. > This can be simplified by introducing a device-managed version. > > Note the changed error case return value type: > i2c_new_dummy returns NULL whilst devm_new_i2c_dummy returns an ERR_PTR. > > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > Reviewed-by: Peter Rosin <peda@axentia.se> > --- > Documentation/driver-model/devres.txt | 3 +++ > drivers/i2c/i2c-core-base.c | 39 +++++++++++++++++++++++++++++++++++ > include/linux/i2c.h | 3 +++ > 3 files changed, 45 insertions(+) > > diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt > index c180045eb..6e2bccf85 100644 > --- a/Documentation/driver-model/devres.txt > +++ b/Documentation/driver-model/devres.txt > @@ -259,6 +259,9 @@ GPIO > devm_gpio_request_one() > devm_gpio_free() > > +I2C > + devm_i2c_new_dummy > + > IIO > devm_iio_device_alloc() > devm_iio_device_free() > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index bf52cca87..c1db67f9a 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -820,6 +820,45 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) > } > EXPORT_SYMBOL_GPL(i2c_new_dummy); > > +static void devm_i2c_release_dummy(struct device *dev, void *res) > +{ > + i2c_unregister_device(*(struct i2c_client **)res); > +} > + Wolfram will have the last word here, but I would really prefer that you wrap struct i2c_client in a separate devres (e.g. struct i2c_dummy_devres) structure and avoid the cast. I find it a lot more readable even if it only has a single member. > +/** > + * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver > + * @dev: device the managed resource is bound to > + * @adapter: the adapter managing the device > + * @address: seven bit address to be used > + * Context: can sleep > + * > + * This is the device-managed version of i2c_new_dummy. > + * Note the changed return value type: It returns the new i2c client > + * or an ERR_PTR in case of an error. > + */ > +struct i2c_client *devm_i2c_new_dummy(struct device *dev, > + struct i2c_adapter *adapter, > + u16 address) > +{ > + struct i2c_client *ret, **dr; > + > + dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL); > + if (!dr) > + return ERR_PTR(-ENOMEM); > + > + ret = i2c_new_dummy(adapter, address); > + if (!ret) { > + devres_free(dr); > + return ERR_PTR(-EBUSY); This is misleading as EBUSY is not necessarily the error that cased i2c_new_device() to fail. Return NULL here and document that users need to use IS_ERR_OR_NULL() to check for errors. > + } > + > + *dr = ret; > + devres_add(dev, dr); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy); > + > /** > * i2c_new_secondary_device - Helper to get the instantiated secondary address > * and create the associated device > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index a556db976..c27eac1e1 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -383,6 +383,9 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); > extern struct i2c_client * > i2c_new_dummy(struct i2c_adapter *adap, u16 address); > > +extern struct i2c_client * > +devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address); > + > extern struct i2c_client * > i2c_new_secondary_device(struct i2c_client *client, > const char *name, > -- > 2.15.1 > > Thanks, Bartosz
Am 06.12.2017 um 11:36 schrieb Bartosz Golaszewski: > 2017-12-05 20:44 GMT+01:00 Heiner Kallweit <hkallweit1@gmail.com>: >> i2c_new_dummy is typically called from the probe function of the >> driver for the primary i2c client. It requires calls to >> i2c_unregister_device in the error path of the probe function and >> in the remove function. >> This can be simplified by introducing a device-managed version. >> >> Note the changed error case return value type: >> i2c_new_dummy returns NULL whilst devm_new_i2c_dummy returns an ERR_PTR. >> >> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> >> Reviewed-by: Peter Rosin <peda@axentia.se> >> --- >> Documentation/driver-model/devres.txt | 3 +++ >> drivers/i2c/i2c-core-base.c | 39 +++++++++++++++++++++++++++++++++++ >> include/linux/i2c.h | 3 +++ >> 3 files changed, 45 insertions(+) >> >> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt >> index c180045eb..6e2bccf85 100644 >> --- a/Documentation/driver-model/devres.txt >> +++ b/Documentation/driver-model/devres.txt >> @@ -259,6 +259,9 @@ GPIO >> devm_gpio_request_one() >> devm_gpio_free() >> >> +I2C >> + devm_i2c_new_dummy >> + >> IIO >> devm_iio_device_alloc() >> devm_iio_device_free() >> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c >> index bf52cca87..c1db67f9a 100644 >> --- a/drivers/i2c/i2c-core-base.c >> +++ b/drivers/i2c/i2c-core-base.c >> @@ -820,6 +820,45 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) >> } >> EXPORT_SYMBOL_GPL(i2c_new_dummy); >> >> +static void devm_i2c_release_dummy(struct device *dev, void *res) >> +{ >> + i2c_unregister_device(*(struct i2c_client **)res); >> +} >> + > > Wolfram will have the last word here, but I would really prefer that > you wrap struct i2c_client in a separate devres (e.g. struct > i2c_dummy_devres) structure and avoid the cast. I find it a lot more > readable even if it only has a single member. > This cast is a very common pattern in such release callbacks, see e.g. devm_spi_unregister. >> +/** >> + * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver >> + * @dev: device the managed resource is bound to >> + * @adapter: the adapter managing the device >> + * @address: seven bit address to be used >> + * Context: can sleep >> + * >> + * This is the device-managed version of i2c_new_dummy. >> + * Note the changed return value type: It returns the new i2c client >> + * or an ERR_PTR in case of an error. >> + */ >> +struct i2c_client *devm_i2c_new_dummy(struct device *dev, >> + struct i2c_adapter *adapter, >> + u16 address) >> +{ >> + struct i2c_client *ret, **dr; >> + >> + dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL); >> + if (!dr) >> + return ERR_PTR(-ENOMEM); >> + >> + ret = i2c_new_dummy(adapter, address); >> + if (!ret) { >> + devres_free(dr); >> + return ERR_PTR(-EBUSY); > > This is misleading as EBUSY is not necessarily the error that cased > i2c_new_device() to fail. Return NULL here and document that users > need to use IS_ERR_OR_NULL() to check for errors. > Indeed returning a fixed error code -EBUSY may not be the best choice. I have another alternative in mind: i2c_new_device brings everything to return a detailed error code. I think of splitting this function into a main function returning a detailed error code and a compatibility wrapper which returns NULL in error case, thus keeping the API stable. I will submit a proposal. >> + } >> + >> + *dr = ret; >> + devres_add(dev, dr); >> + >> + return ret; >> +} >> +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy); >> + >> /** >> * i2c_new_secondary_device - Helper to get the instantiated secondary address >> * and create the associated device >> diff --git a/include/linux/i2c.h b/include/linux/i2c.h >> index a556db976..c27eac1e1 100644 >> --- a/include/linux/i2c.h >> +++ b/include/linux/i2c.h >> @@ -383,6 +383,9 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); >> extern struct i2c_client * >> i2c_new_dummy(struct i2c_adapter *adap, u16 address); >> >> +extern struct i2c_client * >> +devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address); >> + >> extern struct i2c_client * >> i2c_new_secondary_device(struct i2c_client *client, >> const char *name, >> -- >> 2.15.1 >> >> > > Thanks, > Bartosz >
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index c180045eb..6e2bccf85 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -259,6 +259,9 @@ GPIO devm_gpio_request_one() devm_gpio_free() +I2C + devm_i2c_new_dummy + IIO devm_iio_device_alloc() devm_iio_device_free() diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index bf52cca87..c1db67f9a 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -820,6 +820,45 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) } EXPORT_SYMBOL_GPL(i2c_new_dummy); +static void devm_i2c_release_dummy(struct device *dev, void *res) +{ + i2c_unregister_device(*(struct i2c_client **)res); +} + +/** + * devm_i2c_new_dummy - return a new i2c device bound to a dummy driver + * @dev: device the managed resource is bound to + * @adapter: the adapter managing the device + * @address: seven bit address to be used + * Context: can sleep + * + * This is the device-managed version of i2c_new_dummy. + * Note the changed return value type: It returns the new i2c client + * or an ERR_PTR in case of an error. + */ +struct i2c_client *devm_i2c_new_dummy(struct device *dev, + struct i2c_adapter *adapter, + u16 address) +{ + struct i2c_client *ret, **dr; + + dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL); + if (!dr) + return ERR_PTR(-ENOMEM); + + ret = i2c_new_dummy(adapter, address); + if (!ret) { + devres_free(dr); + return ERR_PTR(-EBUSY); + } + + *dr = ret; + devres_add(dev, dr); + + return ret; +} +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy); + /** * i2c_new_secondary_device - Helper to get the instantiated secondary address * and create the associated device diff --git a/include/linux/i2c.h b/include/linux/i2c.h index a556db976..c27eac1e1 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -383,6 +383,9 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); extern struct i2c_client * i2c_new_dummy(struct i2c_adapter *adap, u16 address); +extern struct i2c_client * +devm_i2c_new_dummy(struct device *dev, struct i2c_adapter *adap, u16 address); + extern struct i2c_client * i2c_new_secondary_device(struct i2c_client *client, const char *name,