On 17/06/2024 15:48, Simon Trimmer wrote:
From: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Sent: Monday, June 17, 2024 3:34 PM
On 17/06/2024 15:04, Mark Brown wrote:
On Mon, Jun 17, 2024 at 02:53:38PM +0100, Simon Trimmer wrote:
IRQ lookup functions such as those in ACPI can return error values when
an IRQ is not defined. The i2c core driver converts the error codes to
a
value of 0 and the SPI bus driver passes them unaltered to client
device
drivers.
The cs35l56 driver should only accept positive non-zero values as IRQ
numbers.
Have all architectures removed 0 as a valid IRQ?
From discussion threads we can find 0 might still used on x86 for a
legacy device.
But the conversations we can find on this don't seem to exclude passing
a negative error number, just that 0 can normally be assumed invalid.
The kerneldoc for SPI says:
* @irq: Negative, or the number passed to request_irq() to receive
* interrupts from this device.
Yes and the threads of these lore links in these commits are rather feisty
ce753ad1549c platform: finally disallow IRQ0 in platform_get_irq() and its
ilk
a85a6c86c25b driver core: platform: Clarify that IRQ 0 is invalid
So 0 is invalid. Question is: is it also valid to pass -ve errors, or is
0 the _only_ invalid value?
