On Fri, 21 May 2021, Robert Marko wrote: > On Thu, May 20, 2021 at 8:49 AM Lee Jones <lee.jones@xxxxxxxxxx> wrote: > > > > On Wed, 19 May 2021, Michael Walle wrote: > > > > > Hi, > > > > > > Am 2021-05-19 13:53, schrieb Robert Marko: > > > > On Thu, May 6, 2021 at 6:34 PM Michael Walle <michael@xxxxxxxx> wrote: > > > > > Am 2021-04-30 14:35, schrieb Robert Marko: > > > > > > Delta TN48M switches have a Lattice CPLD that serves > > > > > > multiple purposes including being a GPIO expander. > > > > > > So lets add the MFD core driver for it. > > > > > > > > > > Did you have a look at mfd/simple-mfd-i2c.c? > > > > > > > > Yes, that was my first idea but we have a requirement to expose CPLD > > > > information via debugfs as there are userspace applications using it. > > > > And simple-mfd-i2c does not allow us to do so. > > > > > > Mh, last time Lee wasn't very fond of having a driver that just populates > > > sub-drivers while doing almost nothing itself. See > > > https://lore.kernel.org/lkml/20200605065709.GD3714@dell/ > > > > Right. I still feel that way. > > > > > That being said, I'd also like to expose our CPLD version, but until now > > > haven't found a good solution. > > > > Why though? Does S/W *need* it? > Because we have userspace S/W that uses it as the same CPLD is in > multiple variants of the board but the correct board model is set during > manufacturing and we can read it from the CPLD. > > We also have information about PSU1 and PSU2(Some models only) > power good, whether they are present and some other info that I need > to expose as these are monitored in userspace. > > I planned to do that via the hwmon driver but according to Guenther they > are not hwmon attributes and I agree. > > Would it be possible to have a dedicated driver that would only expose > the required information via debugfs? > Then I could simply use the simple I2C MFD driver with only a GPIO > driver on top of it. Yes, I was going to suggest that. It should probably live in drivers/misc. -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
