Messages in this thread | | | Date | Tue, 20 Jan 2015 16:58:00 +0100 | From | Javier Martinez Canillas <> | Subject | Re: [PATCH RESEND v2 3/7] mfd: cros_ec: Add cros_ec_lpc driver for x86 devices |
| |
Hello Lee,
On 01/20/2015 09:11 AM, Lee Jones wrote: > On Fri, 02 Jan 2015, Javier Martinez Canillas wrote: > >> From: Bill Richardson <wfrichar@chromium.org> >> >> This adds the LPC interface to the Chrome OS EC. Like the >> I2C and SPI drivers, this allows userspace access to the EC. > > I'm fairly certain that this is _not_ an MFD device. Please locate it > to the proper subsystem (input?). >
Sorry, it wasn't my intention to use the mfd subsystem as a place to dump random drivers. Is that I still find hard to understand what is the line between what falls under mfd and what doesn't.
For example, I see that mfd drivers are for devices which have multiple functions and the mfd driver is the one that spawns the platform devices and provide an interface to access the I/O registers used by the different platform drivers of the sub-devices.
So, the Embedded Controller driver (drivers/mfd/cros_ec.c) falls into that category and in fact has been in the mfd driver for a long time. Now, if an mfd device support different type of buses (e.g: i2c, spi, etc) I see that both the core driver and the driver for the transport method are in the drivers/mfd directory. As an example:
drivers/mfd/arizona-{core,i2c,spi}.c drivers/mfd/da9052-{core,i2c,spi}.c drivers/mfd/mc13xxx-{core,i2c,spi}.c drivers/mfd/tps65912-{core,i2c,spi}.c drivers/mfd/wm831x-{core,i2c,spi,otp}.c
In the cros_ec case, we already have drivers/mfd/cros_ec_{i2c,spi}.c so since the Low Pin Count is another transport method I thought that this driver belonged to the drivers/mfd directory.
Now, all those drivers may be wrong and the buses don't belong to the mfd subsystem but then I think we need to document that since it seems that is the correct way to do it just by looking at the other drivers.
Best regards, Javier
| |