On Fri, Dec 01, 2023 at 06:11:36PM -0500, Ben Wolsieffer wrote: > On Fri, Dec 01, 2023 at 09:50:33PM +0000, Mark Brown wrote: > > On Fri, Dec 01, 2023 at 04:40:14PM -0500, Ben Wolsieffer wrote: > > This feels like it'd be a good fit for moving to runtime PM - that way > > we avoid bouncing the controller on and off between messages which is > > probably better anyway. The driver already does pinctrl management for > > the device there. > Yes, that probably makes sense. There are a few bits that can only be > configured while the controller is disabled, but it doesn't look like > that applies to any of the ones set in stm32_spi_prepare_msg(). > I'm a little hesitant to make big changes to the driver since I can only > test them on an STM32F7 though. It doesn't seem much more complex than what you're already proposing. > > It also occurs to me that this isn't going to work for devices which > > chip select inverted - for them we can't stop driving chip select at all > > since they need it held high when idle. There aren't that many such > > devices and it'd loose us the PM which is rather awkward... I guess > > that's an incremental issue with a more invasive fix though. > The driver only supports GPIO chip select rather than native, so I don't > think this is a problem. Also, I don't think there's any difference So mentioning the drive seems a bit confusing then? > between inverted or uninverted here. They both either need to be driven > all the time or have pull-up/downs. It's a lot more likely you'll get away with things one way or another for a missing pull down.
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