iic_gpiomux.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10

    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause
    3  *
    4  * Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  */
   27 
   28 /*
   29  * Driver for i2c bus muxes controlled by one or more gpio pins.
   30  *
   31  * This driver has #ifdef FDT sections in it, as if it supports both fdt and
   32  * hinted attachment, but there is currently no support for hinted attachment.
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD$");
   37 
   38 #include "opt_platform.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/bus.h>
   42 #include <sys/gpio.h>
   43 #include <sys/kernel.h>
   44 #include <sys/module.h>
   45 #include <sys/systm.h>
   46 
   47 #include <dev/gpio/gpiobusvar.h>
   48 
   49 #include <dev/iicbus/iicbus.h>
   50 #include <dev/iicbus/mux/iicmux.h>
   51 
   52 #ifdef FDT
   53 #include <dev/ofw/ofw_bus.h>
   54 #include <dev/ofw/ofw_bus_subr.h>
   55 #include <dev/ofw/openfirm.h>
   56 
   57 static struct ofw_compat_data compat_data[] = {
   58         {"i2c-mux-gpio",  true},
   59         {NULL,            false}
   60 };
   61 OFWBUS_PNP_INFO(compat_data);
   62 SIMPLEBUS_PNP_INFO(compat_data);
   63 #endif /* FDT */
   64 
   65 #include <dev/iicbus/iiconf.h>
   66 #include "iicmux.h"
   67 #include "iicmux_if.h"
   68 
   69 struct gpiomux_softc {
   70         struct iicmux_softc mux;
   71         int     idleidx;
   72         int     numpins;
   73         gpio_pin_t pins[IICMUX_MAX_BUSES];
   74 };
   75 
   76 #define IDLE_NOOP       (-1) /* When asked to idle the bus, do nothing. */
   77 
   78 static int
   79 gpiomux_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
   80 {
   81         struct gpiomux_softc *sc = device_get_softc(dev);
   82         int i;
   83 
   84         /*
   85          * The iicmux caller ensures busidx is between 0 and the number of buses
   86          * we passed to iicmux_init_softc(), no need for validation here.  The
   87          * bits in the index number are transcribed to the state of the pins,
   88          * except when we're asked to idle the bus.  In that case, we transcribe
   89          * sc->idleidx to the pins, unless that is IDLE_NOOP (leave the current
   90          * bus selected), in which case we just bail.
   91          */
   92         if (busidx == IICMUX_SELECT_IDLE) {
   93                 if (sc->idleidx == IDLE_NOOP)
   94                         return (0);
   95                 busidx = sc->idleidx;
   96         }
   97 
   98         for (i = 0; i < sc->numpins; ++i)
   99                 gpio_pin_set_active(sc->pins[i], busidx & (1u << i));
  100 
  101         return (0);
  102 }
  103 
  104 static int
  105 gpiomux_probe(device_t dev)
  106 {
  107         int rv;
  108 
  109         rv = ENXIO;
  110 
  111 #ifdef FDT
  112         if (ofw_bus_status_okay(dev) &&
  113             ofw_bus_search_compatible(dev, compat_data)->ocd_data)
  114                 rv = BUS_PROBE_DEFAULT;
  115 #endif
  116 
  117         device_set_desc(dev, "I2C GPIO Mux");
  118 
  119         return (rv);
  120 }
  121 
  122 static void
  123 gpiomux_release_pins(struct gpiomux_softc *sc)
  124 {
  125         int i;
  126 
  127         for (i = 0; i < sc->numpins; ++i)
  128                 gpio_pin_release(sc->pins[i]);
  129 }
  130 
  131 static int
  132 gpiomux_attach(device_t dev)
  133 {
  134         struct gpiomux_softc *sc = device_get_softc(dev);
  135         ssize_t len;
  136         device_t busdev;
  137         int err, i, idlebits, numchannels;
  138         pcell_t propval;
  139         phandle_t node;
  140 
  141         node = ofw_bus_get_node(dev);
  142 
  143         /*
  144          * Locate the gpio pin(s) that control the mux hardware.  There can be
  145          * multiple pins, but there must be at least one.
  146          */
  147         for (i = 0; ; ++i) {
  148                 err = gpio_pin_get_by_ofw_propidx(dev, node, "mux-gpios", i,
  149                     &sc->pins[i]);
  150                 if (err != 0) {
  151                         break;
  152                 }
  153         }
  154         sc->numpins = i;
  155         if (sc->numpins == 0) {
  156                 device_printf(dev, "cannot acquire pins listed in mux-gpios\n");
  157                 if (err == 0)
  158                         err = ENXIO;
  159                 goto errexit;
  160         }
  161         numchannels = 1u << sc->numpins;
  162         if (numchannels > IICMUX_MAX_BUSES) {
  163                 device_printf(dev, "too many mux-gpios pins for max %d buses\n",
  164                     IICMUX_MAX_BUSES);
  165                 err = EINVAL;
  166                 goto errexit;
  167         }
  168 
  169         /*
  170          * We don't have a parent/child relationship to the upstream bus, we
  171          * have to locate it via the i2c-parent property.  Explicitly tell the
  172          * user which upstream we're associated with, since the normal attach
  173          * message is going to mention only our actual parent.
  174          */
  175         len = OF_getencprop(node, "i2c-parent", &propval, sizeof(propval));
  176         if (len != sizeof(propval)) {
  177                 device_printf(dev, "cannot obtain i2c-parent property\n");
  178                 err = ENXIO;
  179                 goto errexit;
  180         }
  181         busdev = OF_device_from_xref((phandle_t)propval);
  182         if (busdev == NULL) {
  183                 device_printf(dev,
  184                     "cannot find device referenced by i2c-parent property\n");
  185                 err = ENXIO;
  186                 goto errexit;
  187         }
  188         device_printf(dev, "upstream bus is %s\n", device_get_nameunit(busdev));
  189 
  190         /*
  191          * If there is an idle-state property, that is the value we set the pins
  192          * to when the bus is idle, otherwise idling the bus is a no-op
  193          * (whichever bus was last accessed remains active).
  194          */
  195         len = OF_getencprop(node, "idle-state", &propval, sizeof(propval));
  196         if (len == sizeof(propval)) {
  197                 if ((int)propval >= numchannels) {
  198                         device_printf(dev,
  199                             "idle-state property %d exceeds channel count\n",
  200                             propval);
  201                 }
  202                 sc->idleidx = (int)propval;
  203                 idlebits = sc->idleidx;
  204         } else {
  205                 sc->idleidx = IDLE_NOOP;
  206                 idlebits = 0;
  207         }
  208 
  209         /* Preset the mux to the idle state to get things started. */
  210         for (i = 0; i < sc->numpins; ++i) {
  211                 gpio_pin_setflags(sc->pins[i], GPIO_PIN_OUTPUT);
  212                 gpio_pin_set_active(sc->pins[i], idlebits & (1u << i));
  213         }
  214 
  215         /* Init the core driver, have it add our child downstream buses. */
  216         if ((err = iicmux_attach(dev, busdev, numchannels)) == 0)
  217                 bus_generic_attach(dev);
  218 
  219 errexit:
  220 
  221         if (err != 0)
  222                 gpiomux_release_pins(sc);
  223 
  224         return (err);
  225 }
  226 
  227 static int
  228 gpiomux_detach(device_t dev)
  229 {
  230         struct gpiomux_softc *sc = device_get_softc(dev);
  231         int err;
  232 
  233         if ((err = iicmux_detach(dev)) != 0)
  234                 return (err);
  235 
  236         gpiomux_release_pins(sc);
  237 
  238         return (0);
  239 }
  240 
  241 static device_method_t gpiomux_methods[] = {
  242         /* device methods */
  243         DEVMETHOD(device_probe,                 gpiomux_probe),
  244         DEVMETHOD(device_attach,                gpiomux_attach),
  245         DEVMETHOD(device_detach,                gpiomux_detach),
  246 
  247         /* iicmux methods */
  248         DEVMETHOD(iicmux_bus_select,            gpiomux_bus_select),
  249 
  250         DEVMETHOD_END
  251 };
  252 
  253 DEFINE_CLASS_1(iic_gpiomux, iic_gpiomux_driver, gpiomux_methods,
  254     sizeof(struct gpiomux_softc), iicmux_driver);
  255 DRIVER_MODULE(iic_gpiomux, simplebus, iic_gpiomux_driver, 0, 0);
  256 DRIVER_MODULE(iic_gpiomux, ofw_simplebus, iic_gpiomux_driver, 0, 0);
  257 
  258 #ifdef FDT
  259 DRIVER_MODULE(ofw_iicbus, iic_gpiomux, ofw_iicbus_driver, 0, 0);
  260 #else
  261 DRIVER_MODULE(iicbus, iic_gpiomux, iicbus_driver, 0, 0);
  262 #endif
  263 
  264 MODULE_DEPEND(iic_gpiomux, iicmux, 1, 1, 1);
  265 MODULE_DEPEND(iic_gpiomux, iicbus, 1, 1, 1);

Cache object: 3ec0de2f25953c67676af3aac11a2ae1

[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.

FreeBSD/Linux Kernel Cross Reference sys/dev/iicbus/mux/iic_gpiomux.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/iicbus/mux/iic_gpiomux.c