Hi, On Sun, Oct 08, 2017 at 10:51:52AM +0200, Marcel Holtmann wrote: > Hi Sebastian, > > >>> UART devices is expected to be enumerated by SerDev subsystem. > >>> > >>> During ACPI scan, serial devices behind SPI, I2C or UART buses are not > >>> enumerated, allowing them to be enumerated by their respective parents. > >>> > >>> Rename *spi_i2c_slave* to *serial_bus_slave* as this will be used for serial > >>> devices on serial buses (SPI, I2C or UART). > >>> > >>> On Macs an empty ResourceTemplate is returned for uart slaves. > >>> Instead the device properties "baud", "parity", "dataBits", "stopBits" are > >>> provided. Add a check for "baud" in acpi_is_serial_bus_slave(). > >>> > >>> Signed-off-by: Frédéric Danis <frederic.danis.oss@xxxxxxxxx> > >> > >> So just to reiterate what I just mentioned in a comment to one of Hans's > >> hci_bcm patches: > >> > >> This one would silently break PM for such devices on any system which > >> does not have serdev enabled (as the corresponding platform devices > >> would no longer be registered). And with serdev enabled, hciattach > >> (btattach) would start failing as the tty device would no longer be > >> registered (but I assume everyone is aware of that, and fine with it, by > >> now). > >> > >> Perhaps the hci_bcm driver should start depending on > >> SERIAL_DEV_CTRL_TTYPORT when ACPI is enabled? > > > > ACPI and DT both need SERIAL_DEV_CTRL_TTYPORT to work properly, > > since SERIAL_DEV_CTRL_TTYPORT is the only controller implemented > > for serdev. If any other controller is implemented that one could > > also be used. > > > > I wonder if we should just hide SERIAL_DEV_CTRL_TTYPORT and enable > > it together with SERDEV. I suspect that we won't see any other > > controller (it would be a UART device, that is not registered as > > tty device) in the next few years and the extra option seems to > > confuse people. > > I wonder if we should just default SERIAL_DEV_CTRL_TTYPORT=y when > DT or ACPI is enabled. Then no driver would have to select or > depend on it. This is not related to DT/ACPI. SERIAL_DEV_CTRL_TTYPORT is a serdev controller driver, that registers serdev controller devices for each tty. It will also be used by clients, that are registered via board code. -- Sebastian
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