Message ID | ad93148a-027c-8610-0b14-e83f6f0d7472@gmail.com |
---|---|
State | Superseded |
Headers | show |
Series | i2c: introduce devm_i2c_new_dummy and use it in at24 driver | expand |
2017-12-15 18:44 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: Bartosz Golaszewski <brgl@bgdev.pl> > --- > v2: > - use new function _i2c_new_dummy with detailed error codes > v3: > - no changes > v4: > - reflect renaming to __i2c_new_dummy > - add reviewed-by > --- > Documentation/driver-model/devres.txt | 3 +++ > drivers/i2c/i2c-core-base.c | 38 +++++++++++++++++++++++++++++++++++ > include/linux/i2c.h | 3 +++ > 3 files changed, 44 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 3b962456c..7a6669f07 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -864,6 +864,44 @@ 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); > + While I understand that this pattern has been used before I still think it's much less readable than using a separate devm struct containing the i2c_client. Please take a look at kernel/irq/irq_sim.c: while I may be biased since I added that code, I think it's cleaner to avoid the casts and double pointers. Remember - we prefer readability over saving three lines of code (and probably none in its compiled form). Thanks, Bartosz > + ret = __i2c_new_dummy(adapter, address); > + if (IS_ERR(ret)) { > + devres_free(dr); > + } else { > + *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 5d7f3c185..aca6ebbb8 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -441,6 +441,9 @@ 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 > >
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 3b962456c..7a6669f07 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -864,6 +864,44 @@ 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 (IS_ERR(ret)) { + devres_free(dr); + } else { + *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 5d7f3c185..aca6ebbb8 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -441,6 +441,9 @@ 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,