Hi Heikki, On 13/04/22 16:07, Heikki Krogerus wrote: > On Wed, Apr 13, 2022 at 03:32:50PM +0530, Aswath Govindraju wrote: >> Hi Heikki, >> >> On 13/04/22 15:04, Heikki Krogerus wrote: >>> Hi Aswath, >>> >>> On Tue, Apr 12, 2022 at 08:20:58PM +0530, Aswath Govindraju wrote: >>>> In some cases the interrupt line from the pd controller may not be >>>> connected. In these cases, poll the status of various events. >>> >>> Well, if the alert/interrupt line is not connected anywhere, then >>> polling is the only way to go. I'm fine with that, but the driver >>> really should be told that there is no interrupt. Using polling >>> whenever request_threaded_irq() returns -EINVAL is wrong. We really >>> should not even attempt to request the interrupt if there is no >>> interrupt for the device. >>> >>> Isn't there any way you can get that information from DT? Or how is >>> the device enumerated in your case? >>> >> >> Would checking if (client->irq) field is populated, to decide between >> polling and interrupts be a good approach? >> >> I am sorry but I did not understand what you meant by device getting >> enumerated. The device is on an I2C bus and gets enumerated based on the >> I2C address provided. The device does not have I2C_IRQ line connected, >> in my case. > > "I2C devices are not enumerated at hardware level": > https://www.kernel.org/doc/html/latest/i2c/instantiating-devices.html > > So your PD controller I2C slave device has to be either described in > Devicetree or ACPI tables, or there is a board file or platform driver > that actually populates the device for it. > > Can you tell a little bit about the platform you are running? Is it > ARM, x86, or what, and is it ACPI or DT platform? > Got it. Currently I am testing on a ARM platform and the I2C device tree nodes are populated in the device tree. This is how the PD controller gets enumerated. > thanks, > -- Thanks, Aswath
