On 2017-07-17 17:24, Ulrich Hecht wrote: > Adds an interface for slave device multiplexing using the mux subsystem. > > Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@xxxxxxxxx> > --- > drivers/tty/serdev/Kconfig | 3 +++ > drivers/tty/serdev/Makefile | 1 + > drivers/tty/serdev/core.c | 14 +++++++++- > drivers/tty/serdev/mux.c | 66 +++++++++++++++++++++++++++++++++++++++++++++ > include/linux/serdev.h | 16 ++++++++--- > 5 files changed, 96 insertions(+), 4 deletions(-) > create mode 100644 drivers/tty/serdev/mux.c > > diff --git a/drivers/tty/serdev/Kconfig b/drivers/tty/serdev/Kconfig > index cdc6b82..9096b71 100644 > --- a/drivers/tty/serdev/Kconfig > +++ b/drivers/tty/serdev/Kconfig > @@ -13,4 +13,7 @@ config SERIAL_DEV_CTRL_TTYPORT > depends on TTY > depends on SERIAL_DEV_BUS != m > > +config SERIAL_DEV_MUX > + bool "Serial device multiplexer support" Here, you should select MULTIPLEXER And, instead of adding a config option, you might want to consider making the mux optional instead. See https://lkml.org/lkml/2017/7/14/655 > + > endif > diff --git a/drivers/tty/serdev/Makefile b/drivers/tty/serdev/Makefile > index 0cbdb94..d713381 100644 > --- a/drivers/tty/serdev/Makefile > +++ b/drivers/tty/serdev/Makefile > @@ -1,5 +1,6 @@ > serdev-objs := core.o > > obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o > +obj-$(CONFIG_SERIAL_DEV_MUX) += mux.o > > obj-$(CONFIG_SERIAL_DEV_CTRL_TTYPORT) += serdev-ttyport.o > diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c > index 1fbaa4c..92c5bfa 100644 > --- a/drivers/tty/serdev/core.c > +++ b/drivers/tty/serdev/core.c > @@ -305,7 +305,8 @@ struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl) > return NULL; > > serdev->ctrl = ctrl; > - ctrl->serdev = serdev; > + if (!ctrl->serdev) > + ctrl->serdev = serdev; > device_initialize(&serdev->dev); > serdev->dev.parent = &ctrl->dev; > serdev->dev.bus = &serdev_bus_type; > @@ -368,6 +369,8 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl) > struct serdev_device *serdev = NULL; > int err; > bool found = false; > + int nr = 0; > + u32 reg; > > for_each_available_child_of_node(ctrl->dev.of_node, node) { > if (!of_get_property(node, "compatible", NULL)) > @@ -380,6 +383,10 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl) > continue; > > serdev->dev.of_node = node; > + serdev->nr = nr++; > + > + if (!of_property_read_u32(node, "reg", ®)) > + serdev->mux_addr = reg; > > err = serdev_device_add(serdev); > if (err) { > @@ -414,6 +421,11 @@ int serdev_controller_add(struct serdev_controller *ctrl) > if (ret) > return ret; > > +#ifdef CONFIG_SERIAL_DEV_MUX > + if (of_serdev_register_mux(ctrl) == -EPROBE_DEFER) > + return -EPROBE_DEFER; > +#endif > + > ret = of_serdev_register_devices(ctrl); > if (ret) > goto out_dev_del; > diff --git a/drivers/tty/serdev/mux.c b/drivers/tty/serdev/mux.c > new file mode 100644 > index 0000000..fc9405b > --- /dev/null > +++ b/drivers/tty/serdev/mux.c > @@ -0,0 +1,66 @@ > +/* > + * Copyright (C) 2017 Ulrich Hecht > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 and > + * only version 2 as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/mux/consumer.h> > +#include <linux/mux/driver.h> > +#include <linux/of_gpio.h> > +#include <linux/serdev.h> > +#include <linux/slab.h> > + > +int serdev_device_mux_select(struct serdev_device *serdev) > +{ > + struct mux_control *mux = serdev->ctrl->mux; > + int ret; > + > + if (!mux) > + return -EINVAL; > + > + ret = mux_control_select(mux, serdev->mux_addr); > + serdev->ctrl->mux_do_not_deselect = ret < 0; > + > + serdev->ctrl->serdev = serdev; > + > + return ret; > +} > + > +int serdev_device_mux_deselect(struct serdev_device *serdev) > +{ > + struct mux_control *mux = serdev->ctrl->mux; > + > + if (!mux) > + return -EINVAL; > + > + if (!serdev->ctrl->mux_do_not_deselect) > + return mux_control_deselect(mux); > + else > + return 0; > +} > + > +int of_serdev_register_mux(struct serdev_controller *ctrl) > +{ > + struct mux_control *mux; > + struct device *dev = &ctrl->dev; > + > + mux = devm_mux_control_get(dev, NULL); > + > + if (IS_ERR(mux)) { > + if (PTR_ERR(mux) != -EPROBE_DEFER) > + dev_err(dev, "failed to get control mux\n"); > + return PTR_ERR(mux); > + } > + > + ctrl->mux = mux; > + > + return 0; > +} > + > diff --git a/include/linux/serdev.h b/include/linux/serdev.h > index 8b67fcd..26d5994 100644 > --- a/include/linux/serdev.h > +++ b/include/linux/serdev.h > @@ -17,6 +17,7 @@ > #include <linux/device.h> > #include <linux/termios.h> > #include <linux/delay.h> > +#include <linux/rtmutex.h> > > struct serdev_controller; > struct serdev_device; > @@ -51,6 +52,7 @@ struct serdev_device { > const struct serdev_device_ops *ops; > struct completion write_comp; > struct mutex write_lock; > + int mux_addr; > }; > > static inline struct serdev_device *to_serdev_device(struct device *d) > @@ -76,6 +78,8 @@ static inline struct serdev_device_driver *to_serdev_device_driver(struct device > return container_of(d, struct serdev_device_driver, driver); > } > > +int of_serdev_register_mux(struct serdev_controller *ctrl); > + > /* > * serdev controller structures > */ > @@ -97,14 +101,18 @@ struct serdev_controller_ops { > * struct serdev_controller - interface to the serdev controller > * @dev: Driver model representation of the device. > * @nr: number identifier for this controller/bus. > - * @serdev: Pointer to slave device for this controller. > + * @serdev: Pointer to active slave device for this controller. > * @ops: Controller operations. > + * @mux: Slave multiplexer control. > + * @mux_do_not_deselect: Set if slave selection failed. > */ > struct serdev_controller { > struct device dev; > unsigned int nr; > struct serdev_device *serdev; > const struct serdev_controller_ops *ops; > + struct mux_control *mux; > + int mux_do_not_deselect; > }; > > static inline struct serdev_controller *to_serdev_controller(struct device *d) > @@ -172,7 +180,7 @@ static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl > { > struct serdev_device *serdev = ctrl->serdev; > > - if (!serdev || !serdev->ops->write_wakeup) > + if (!serdev || !serdev->ops || !serdev->ops->write_wakeup) > return; > > serdev->ops->write_wakeup(serdev); > @@ -184,7 +192,7 @@ static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl, > { > struct serdev_device *serdev = ctrl->serdev; > > - if (!serdev || !serdev->ops->receive_buf) > + if (!serdev || !serdev->ops || !serdev->ops->receive_buf) > return -EINVAL; > > return serdev->ops->receive_buf(serdev, data, count); > @@ -204,6 +212,8 @@ void serdev_device_write_wakeup(struct serdev_device *); > int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, unsigned long); > void serdev_device_write_flush(struct serdev_device *); > int serdev_device_write_room(struct serdev_device *); > +int serdev_device_mux_select(struct serdev_device *); > +int serdev_device_mux_deselect(struct serdev_device *); > > /* > * serdev device driver functions >
