Re: [PATCH v8 2/3] i2c: core: add device-managed version of i2c_new_dummy

[Bartosz Golaszewski <brgl@bgdev.pl>]

czw., 16 maj 2019 o 23:13 Wolfram Sang
<wsa+renesas@sang-engineering.com> napisał(a):
>
> From: 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_i2c_new_dummy_device returns an ERR_PTR.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> [wsa: rename new functions and fix minor kdoc issues]
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  Documentation/driver-model/devres.txt |  3 ++
>  drivers/i2c/i2c-core-base.c           | 44 +++++++++++++++++++++++++++
>  include/linux/i2c.h                   |  3 ++
>  3 files changed, 50 insertions(+)
>
> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
> index 99994a461359..69c7fa7f616c 100644
> --- a/Documentation/driver-model/devres.txt
> +++ b/Documentation/driver-model/devres.txt
> @@ -271,6 +271,9 @@ GPIO
>    devm_gpio_request_one()
>    devm_gpio_free()
>
> +I2C
> +  devm_i2c_new_dummy_device()
> +
>  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 9c38dde73366..d389d4fb0623 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -929,6 +929,50 @@ struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
>  }
>  EXPORT_SYMBOL_GPL(i2c_new_dummy);
>
> +struct i2c_dummy_devres {
> +       struct i2c_client *client;
> +};
> +
> +static void devm_i2c_release_dummy(struct device *dev, void *res)
> +{
> +       struct i2c_dummy_devres *this = res;
> +
> +       i2c_unregister_device(this->client);
> +}
> +
> +/**
> + * devm_i2c_new_dummy_device - 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_device. It returns the
> + * new i2c client or an ERR_PTR in case of an error.
> + */
> +struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
> +                                            struct i2c_adapter *adapter,
> +                                            u16 address)
> +{
> +       struct i2c_dummy_devres *dr;
> +       struct i2c_client *client;
> +
> +       dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
> +       if (!dr)
> +               return ERR_PTR(-ENOMEM);
> +
> +       client = i2c_new_dummy_device(adapter, address);
> +       if (IS_ERR(client)) {
> +               devres_free(dr);
> +       } else {
> +               dr->client = client;
> +               devres_add(dev, dr);
> +       }
> +
> +       return client;
> +}
> +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
> +
>  /**
>   * 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 be27062f8ed1..6c4db54714f6 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -469,6 +469,9 @@ 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_device(struct device *dev, struct i2c_adapter *adap, u16 address);
> +
>  extern struct i2c_client *
>  i2c_new_secondary_device(struct i2c_client *client,
>                                 const char *name,
> --
> 2.19.1
>

Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>