Re: [PATCH 15/18] i2c: i2c-core-acpi: Add i2c_acpi_dev_name()

Laurent Pinchart
2020-11-30T17:12:23Z

Hi Daniel,

Thank you for the patch.

On Mon, Nov 30, 2020 at 01:31:26PM +0000, Daniel Scally wrote:
> Some places in the kernel allow users to map resources to a device
> using device name (for example, gpiod_lookup_table). Currently
> this involves waiting for the i2c_client to have been registered so we
> can use dev_name(&client->dev). Adding this function means that we can
> achieve the same thing without having to wait to the i2c device.
>
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
> ---
> Changes since RFC v3:
>
> - Patch introduced
>
> drivers/i2c/i2c-core-acpi.c | 14 ++++++++++++++
> include/linux/i2c.h | 5 +++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
> index 37c510d9347a..d3a653eac79e 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -497,6 +497,20 @@ struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
> }
> EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
>
> +/**
> + * i2c_acpi_dev_name - Construct i2c device name for devs sourced from ACPI
> + * @adev: ACPI device to construct the name for
> + *
> + * Prefixes "i2c-" to the ACPI device name, for use in i2c_dev_set_name() and
> + * also anywhere else in the kernel that needs to refer to an i2c device by
> + * name but before they have been instantiated.

The documentation should state that the caller must free the return
value.

> + */
> +char *i2c_acpi_dev_name(struct acpi_device *adev)
> +{
> + return kasprintf(GFP_KERNEL, "i2c-%s", acpi_dev_name(adev));
> +}
> +EXPORT_SYMBOL_GPL(i2c_acpi_dev_name);
> +
> #ifdef CONFIG_ACPI_I2C_OPREGION
> static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
> u8 cmd, u8 *data, u8 data_len)
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 56622658b215..ab0e505b2ca6 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -995,6 +995,7 @@ bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
> u32 i2c_acpi_find_bus_speed(struct device *dev);
> struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
> struct i2c_board_info *info);
> +char *i2c_acpi_dev_name(struct acpi_device *adev);
> struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
> #else
> static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
> @@ -1011,6 +1012,10 @@ static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
> {
> return ERR_PTR(-ENODEV);
> }
> +static inline char *i2c_acpi_dev_name(struct acpi_device *adev)
> +{
> + return NULL;
> +}
> static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
> {
> return NULL;

--
Regards,

Laurent Pinchart