On Tue, Apr 15, 2008 at 03:47:41PM +0200, Laurent Pinchart wrote: > On Tuesday 15 April 2008 15:40, Anton Vorontsov wrote: > > On Tue, Apr 15, 2008 at 03:22:33PM +0200, Laurent Pinchart wrote: > > > Hi everybody, > > > > > > I'm implementing flow control and modem control lines support in the > > > cpm_uart driver. > > > > > > The implementation is based on the GPIO lib. Modem control lines are > > > described in the device tree as GPIO resources and accessed through the OF > > > GPIO bindings. The I/O ports have to be initialized as GPIOs in the > > > platform-specific code. > > > > > > Reading and writing the modem control lines isn't an issue, but > > > activating > > > hardware flow control is more complex. The driver needs to turn dedicated > > > functions on and off for the RTS and CTS signals, and the GPIO API > > > doesn't > > > provide a way to access the PPAR* registers (which does make sense - > > > although arguably - as PPAR* control specific functions, not GPIOs). > > > > > > Hardcoding RTS and CTS lines control in the driver is not an option I want > > > to consider. Extending the GPIO API to handled special functions has been > > > nacked in the past (see > > > http://ozlabs.org/pipermail/linuxppc-dev/2008-February/051241.html). An > > > option would be to export gpio_to_chip from drivers/gpio/gpiolib.c and > > > use > > > cpm1/2_set_pin in the cpm_uart driver. > > > > Since you have successfuly ported QE USB controller onto CPM USB > > hardware, now it's obvious that we will need generic gpio_set_dedicated() > > function. So I would rather beg David to accept gpio_set_dedicated() > > approach instead of exporting gpio_to_chip(). That way we'll kill two > > birds with one stone. > > Or maybe some kind of gpio_set_option() with flags specific to the > controller ? This could be used to enable open-drain outputs or internal > pull-ups for instance.
Yes, probably this name. The purpose will be the same anyway. ;-) -- Anton Vorontsov email: [EMAIL PROTECTED] irc://irc.freenode.net/bd2 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
