Hi Tony, On Tue, Apr 21, 2020 at 04:27:48PM -0700, Tony Lindgren wrote: > Hi all, > > Here's v4 set of n_gsm serdev support patches, and the related protocol > driver for the modem found on Motorola Mapphone phones and tablets > like droid4. > > This series only adds basic character device support for the serdev > driver. Other serdev consumer drivers for specific devices will be > posted separately. I'm still missing an architectural (design) overview here -- reviewer time is a scarce resource. I also suggested earlier that you include, at least as an RFC, one or more of your child-device drivers so that we can see how this ends up being used in the end (including an example devicetree). Some high-level comments until then: I'm not sure that a plain chardev interface for the mux channels is the right interface. The n_gsm ldisc exposes tty devices and I think your serdev adaptation should continue to do that. On that note; you're not actually adding general TS 27.010 serdev support, but rather some hooks and a custom driver and interface (mfd + /dev/motmdmN) for one particular modem. I'd rather see a generic implementation which can be used with other modems and that continues to expose a /dev/gsmttyN interface to which we could attach serdev clients instead (and not create a motmdm serdev replica of sorts). I know the location of this driver has been up for discussion already, but drivers/tty/serdev/protocol still isn't right (e.g. we don't have an drivers/i2c/protocol directory where we stuff random i2c client drivers). It's an mfd + custom chardev driver for a modem and related to n_gsm (even more if you add generic serdev support). Currently, drivers/mfd or drivers/misc appear to be better choices. Otherwise, n_gsm lives in drivers/tty since it's a line discipline, but it could be moved to a new drivers/modem if needed (cf. the bluetooth hci ldisc). Last, it seems you've based the serdev-ngsm-motmdm.c chardev implementation on a more or less verbatim copy of drivers/gnss/core.c. I'd appreciate if you could mention that in the file header and reproduce the copyright notice if you end up keeping that interface. > Tony Lindgren (4): > tty: n_gsm: Add support for serdev drivers > serdev: ngsm-motmdm: Add Motorola TS 27.010 serdev modem driver for > droid4 > dt-bindings: serdev: motmdm: Add binding for motorola-mdm > ARM: dts: omap4-droid4: Enable basic modem support > > .../serdev/motorola,mapphone-mdm6600.yaml | 34 + > .../boot/dts/motorola-mapphone-common.dtsi | 6 + > drivers/tty/n_gsm.c | 372 +++++ > drivers/tty/serdev/Kconfig | 2 + > drivers/tty/serdev/Makefile | 2 + > drivers/tty/serdev/protocol/Kconfig | 14 + > drivers/tty/serdev/protocol/Makefile | 3 + > .../tty/serdev/protocol/serdev-ngsm-motmdm.c | 1191 +++++++++++++++++ > include/linux/serdev-gsm.h | 168 +++ > 9 files changed, 1792 insertions(+) > create mode 100644 Documentation/devicetree/bindings/serdev/motorola,mapphone-mdm6600.yaml > create mode 100644 drivers/tty/serdev/protocol/Kconfig > create mode 100644 drivers/tty/serdev/protocol/Makefile > create mode 100644 drivers/tty/serdev/protocol/serdev-ngsm-motmdm.c > create mode 100644 include/linux/serdev-gsm.h Johan
