Re: [PATCH v4 4/7] i2c: core: Make i2c_acpi_get_irq available to the rest of the I2C core

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Tue, Jun 11, 2019 at 01:30:58PM +0100, Charles Keepax wrote:
> In preparation for more refactoring make i2c_acpi_get_irq available
> outside i2c-core-acpi.c.
> 
> Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
> ---
> 
> Changes since v3:
>  - Move the change to use the helper function from i2c-core-base into its own patch.
> 
> Thanks,
> Charles
> 
>  drivers/i2c/i2c-core-acpi.c | 15 +++++++++++++--
>  drivers/i2c/i2c-core.h      |  7 +++++++
>  2 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
> index 7d4d66ba752d4..35966cc337dde 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -144,8 +144,17 @@ static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
>  	return 1; /* No need to add resource to the list */
>  }
>  
> -static int i2c_acpi_get_irq(struct acpi_device *adev)
> +/**
> + * i2c_acpi_get_irq - get device IRQ number from ACPI
> + * @client: Pointer to the I2C client device
> + *
> + * Find the IRQ number used by a specific client device.
> + *
> + * Return: The IRQ number or an error code.
> + */
> +int i2c_acpi_get_irq(struct i2c_client *client)
>  {
> +	struct acpi_device *adev = ACPI_COMPANION(&client->adapter->dev);

Is this adev checked for being NULL somewhere below before it is being
dereferenced?

It could explain the issue Benjamin is seeing.

>  	struct list_head resource_list;
>  	int irq = -ENOENT;
>  	int ret;