Hello, On Mon, Oct 28, 2024 at 05:07:49PM +0100, Uwe Kleine-König wrote: > this is iteration v2 to make ad7124 work on de10-nano. (Implicit) v1 is > available at > https://lore.kernel.org/linux-iio/20241024171703.201436-5-u.kleine-koenig@xxxxxxxxxxxx. > > The changes since v1: > > - Write 0 instead of 0x0001 to disable channels. While 0x0001 is the > reset default value for these registers (apart from the channel 0 one) > there is no sensible reason to use that value (i.e. > AD7124_CHANNEL_AINP(0) | AD7124_CHANNEL_AINM(1)) as the value is > reprogrammed before use anyhow. This addresses the feedback that the > magic value 0x0001 should better be constructed using register bit > field defintions. > > - Add maxItems: 1 to the new property defined in the binding patch (Krzysztof) > > - Rename property to rdy-gpios (Rob) > > - Use rdy-gpios only for gpio reading and continue using the usual irq > defintion for the interrupt (Jonathan). I was surprised I can use both the > GPIO as input and the matching irq. > > - patch #1 is new, and use GPIO_ACTIVE_LOW in the gpio descriptor > instead of 2. > > Jonathan voiced concerns about the reliability of this solution and > proposed to implement polling. I'm convinced the solution implemented > here is robust, so I see no need to implement polling today. > > Still open questions: > > - Is rdy-gpios the right name. The line is named ̅R̅D̅Y, so maybe nrdy-gpios? Or > nRDY-gpios? David said that rdy-gpios looks right in combination with the GPIO_ACTIVE_LOW flag. Makes sense to me to negate only in a single location. > - Jonathan wanted some input from ADI about this series and the > hardware details. I think the hardware is understood now reasonably well and from the discussion with tglx it's also clear that the issue is expected and fixed at the right place. Although probably not all hardware configurations can benefit from the modification, I still consider this a beneficial modification because it allows at least some (most?) machines to use the irq instead of polling. There is a patch series on the list for ad7124 (https://lore.kernel.org/linux-iio/cover.1731404695.git.u.kleine-koenig@xxxxxxxxxxxx/) that for now didn't get feedback, and I found another race condition in the sigma_delta driver helper and now wonder how to proceed here. If we agree in general that the rdy-gpios patches are ok to be applied, I'd base the fix for the latest race condition on top of these. Should I better collect all in-flight patches in a single series, or just post the new patches (with a proper --base= parameter to format-patch)? Best regards Uwe
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