Hello Lee, On Wed, 2020-12-02 at 12:57 +0000, Lee Jones wrote: > On Fri, 27 Nov 2020, Vaittinen, Matti wrote: > > > Hello Lee, > > > > On Fri, 2020-11-27 at 08:32 +0000, Lee Jones wrote: > > > On Mon, 23 Nov 2020, Matti Vaittinen wrote: > > > > > > > Add core support for ROHM BD9576MUF and BD9573MUF PMICs which > > > > are > > > > mainly used to power the R-Car series processors. > > > > > > > > Signed-off-by: Matti Vaittinen < > > > > matti.vaittinen@xxxxxxxxxxxxxxxxx> > > > > --- > > > > drivers/mfd/Kconfig | 11 ++++ > > > > drivers/mfd/Makefile | 1 + > > > > drivers/mfd/rohm-bd9576.c | 108 > > > > +++++++++++++++++++++++++++++++ > > > > include/linux/mfd/rohm-bd957x.h | 59 +++++++++++++++++ > > > > include/linux/mfd/rohm-generic.h | 2 + > > > > 5 files changed, 181 insertions(+) > > > > create mode 100644 drivers/mfd/rohm-bd9576.c > > > > create mode 100644 include/linux/mfd/rohm-bd957x.h > > > > > > Looks like a possible candidate for "simple-mfd-i2c". > > > > > > Could you look into that please? > > > > > I must admit I didn't know about "simple-mfd-i2c". Good thing to > > know > > when working with simple devices :) Is this a new thing? > > Yes, it's new. > > > I am unsure I understand the idea fully. Should users put all the > > different regamp configs in this file and just add the device IDs > > with > > pointer to correct config? (BD9576 and BD9573 need volatile > > ranges). > > Also, does this mean each sub-device should have own node and own > > compatible in DT to get correctly load and probed? I guess this > > would > > need a buy-in from Rob too then. > > You should describe the H/W in DT. Yes. And it is described. But I've occasionally received request from DT guys to add some properties directly to MFD node and not to add own sub-node. This is what is done for example with the BD71837/47 clocks - there is no own node for clk - the clk properties are placed directly in MFD node (as was requested by Stephen and Rob back then - I originally had own node for clk). I really have no clear view on when things warrant for own subnode and when they don't - but as far as I can see using simple-mfd-i2c forces one to always have a sub-node / device. Even just a empty node with nothing but the compatible even if device does not need stuff from DT? Anyways, I think this is nice addition for simple drivers. > > By the way - for uneducated eyes like mine this does not look like > > it > > has much to do with MFD as a device - here MFD reminds me of a > > simple- > > bus on top of I2C. > > This is for MFD devices where the parent does little more than create > a shared address space for child devices to operate on - like yours. > > > Anyways, the BD9576 and BD9573 both have a few interrupts for > > OVD/UVD > > conditions and I am expecting that I will be asked to provide the > > regulator notifiers for those. Reason why I omitted the IRQs for > > now is > > that the HW is designed to keep the IRQ asserted for whole error > > duration so some delayed ack mechanism would be needed. I would > > like to > > keep the door open for adding IRQs to MFD core. > > You mean to add an IRQ Domain? Yes. I planned to use regmap-irq and create irq chip in MFD when the over / under voltage / temperature - notifications or watchdog IRQs are needed. Best Regards, Matti Vaittinen
