On 2017-06-14 16:38, Ulrich Hecht wrote: > Hi! > > This is an attempt to add multiplexer support to serdev, specifically > GPIO-based multiplexing. > > Our use case is the Renesas Blanche V2H board with several MAX9260 GMSL > deserializers attached to one serial port. A sample driver that implements > i2c passthrough over the GMSL link is part of this series. This device > wants to be talked to with even parity, so a patch implementing parity > control in serdev is included as well. > > The board-specific part of this series depends on the "pinctrl: sh-pfc: > r8a7792: Add SCIF1 pin groups" patch. > > Please tell me if this is a suitable way to implement this functionality > in serdev, or how to improve it. Thank you. When I look at patch 2/4, I can't help but think that you should perhaps consider the new mux framework available in linux-next [1]. But as the author of that, I'm maybe biased... You then support other means of controlling the mux automatically (i.e. you get free support for non-gpio muxes). You also get support for sharing the mux controller should the same gpio pins control muxes for unrelated functions (which happened for my hw). However, I see that you request the gpios when you select the mux, and free them when you deselect it. That is not how the gpio mux in the mux framework operates; it instead keeps the gpios requested and either leaves the gpios as-is on deselect or sets a specific idle value. But that is perhaps ok for this use-case too? Cheers, peda [1] https://lkml.org/lkml/2017/5/14/160 > CU > Uli > > > Ulrich Hecht (4): > serdev: add method to set parity > serdev: add GPIO-based multiplexer support > max9260: add driver for i2c over GMSL passthrough > ARM: dts: blanche: add SCIF1 and MAX9260 deserializer > > arch/arm/boot/dts/r8a7792-blanche.dts | 45 ++++++ > drivers/media/i2c/Kconfig | 6 + > drivers/media/i2c/Makefile | 1 + > drivers/media/i2c/max9260.c | 294 ++++++++++++++++++++++++++++++++++ > drivers/tty/serdev/Kconfig | 3 + > drivers/tty/serdev/Makefile | 1 + > drivers/tty/serdev/core.c | 55 ++++++- > drivers/tty/serdev/mux-gpio.c | 80 +++++++++ > drivers/tty/serdev/serdev-ttyport.c | 17 ++ > include/linux/serdev.h | 30 +++- > 10 files changed, 528 insertions(+), 4 deletions(-) > create mode 100644 drivers/media/i2c/max9260.c > create mode 100644 drivers/tty/serdev/mux-gpio.c > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
