gpioiic.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause
    3  *
    4  * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org>
    5  * Copyright (c) 2010 Luiz Otavio O Souza
    6  * Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD$");
   32 
   33 #include "opt_platform.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/bus.h>
   38 #include <sys/gpio.h>
   39 #include <sys/kernel.h>
   40 #include <sys/module.h>
   41 
   42 #include <dev/gpio/gpiobusvar.h>
   43 #include <dev/iicbus/iiconf.h>
   44 
   45 #include "gpiobus_if.h"
   46 #include "iicbb_if.h"
   47 
   48 #define GPIOIIC_SCL_DFLT        0
   49 #define GPIOIIC_SDA_DFLT        1
   50 #define GPIOIIC_MIN_PINS        2
   51 
   52 struct gpioiic_softc 
   53 {
   54         device_t        dev;
   55         gpio_pin_t      sclpin;
   56         gpio_pin_t      sdapin;
   57 };
   58 
   59 #ifdef FDT
   60 
   61 #include <dev/ofw/ofw_bus.h>
   62 
   63 static struct ofw_compat_data compat_data[] = {
   64         {"i2c-gpio",  true}, /* Standard devicetree compat string */
   65         {"gpioiic",   true}, /* Deprecated old freebsd compat string */
   66         {NULL,        false}
   67 };
   68 OFWBUS_PNP_INFO(compat_data);
   69 SIMPLEBUS_PNP_INFO(compat_data);
   70 
   71 static phandle_t
   72 gpioiic_get_node(device_t bus, device_t dev)
   73 {
   74 
   75         /* Share our fdt node with iicbus so it can find its child nodes. */
   76         return (ofw_bus_get_node(bus));
   77 }
   78 
   79 static int
   80 gpioiic_setup_fdt_pins(struct gpioiic_softc *sc)
   81 {
   82         phandle_t node;
   83         int err;
   84 
   85         node = ofw_bus_get_node(sc->dev);
   86 
   87         /*
   88          * Historically, we used the first two array elements of the gpios
   89          * property.  The modern bindings specify separate scl-gpios and
   90          * sda-gpios properties.  We cope with whichever is present.
   91          */
   92         if (OF_hasprop(node, "gpios")) {
   93                 if ((err = gpio_pin_get_by_ofw_idx(sc->dev, node,
   94                     GPIOIIC_SCL_DFLT, &sc->sclpin)) != 0) {
   95                         device_printf(sc->dev, "invalid gpios property\n");
   96                         return (err);
   97                 }
   98                 if ((err = gpio_pin_get_by_ofw_idx(sc->dev, node,
   99                     GPIOIIC_SDA_DFLT, &sc->sdapin)) != 0) {
  100                         device_printf(sc->dev, "ivalid gpios property\n");
  101                         return (err);
  102                 }
  103         } else {
  104                 if ((err = gpio_pin_get_by_ofw_property(sc->dev, node,
  105                     "scl-gpios", &sc->sclpin)) != 0) {
  106                         device_printf(sc->dev, "missing scl-gpios property\n");
  107                         return (err);
  108                 }
  109                 if ((err = gpio_pin_get_by_ofw_property(sc->dev, node,
  110                     "sda-gpios", &sc->sdapin)) != 0) {
  111                         device_printf(sc->dev, "missing sda-gpios property\n");
  112                         return (err);
  113                 }
  114         }
  115         return (0);
  116 }
  117 #endif /* FDT */
  118 
  119 static int
  120 gpioiic_setup_hinted_pins(struct gpioiic_softc *sc)
  121 {
  122         device_t busdev;
  123         const char *busname, *devname;
  124         int err, numpins, sclnum, sdanum, unit;
  125 
  126         devname = device_get_name(sc->dev);
  127         unit = device_get_unit(sc->dev);
  128         busdev = device_get_parent(sc->dev);
  129 
  130         /*
  131          * If there is not an "at" hint naming our actual parent, then we
  132          * weren't instantiated as a child of gpiobus via hints, and we thus
  133          * can't access ivars that only exist for such children.
  134          */
  135         if (resource_string_value(devname, unit, "at", &busname) != 0 ||
  136             (strcmp(busname, device_get_nameunit(busdev)) != 0 &&
  137              strcmp(busname, device_get_name(busdev)) != 0)) {
  138                 return (ENOENT);
  139         }
  140 
  141         /* Make sure there were hints for at least two pins. */
  142         numpins = gpiobus_get_npins(sc->dev);
  143         if (numpins < GPIOIIC_MIN_PINS) {
  144 #ifdef FDT
  145                 /*
  146                  * Be silent when there are no hints on FDT systems; the FDT
  147                  * data will provide the pin config (we'll whine if it doesn't).
  148                  */
  149                 if (numpins == 0) {
  150                         return (ENOENT);
  151                 }
  152 #endif
  153                 device_printf(sc->dev, 
  154                     "invalid pins hint; it must contain at least %d pins\n",
  155                     GPIOIIC_MIN_PINS);
  156                 return (EINVAL);
  157         }
  158 
  159         /*
  160          * Our parent bus has already parsed the pins hint and it will use that
  161          * info when we call gpio_pin_get_by_child_index().  But we have to
  162          * handle the scl/sda index hints that tell us which of the two pins is
  163          * the clock and which is the data.  They're optional, but if present
  164          * they must be a valid index (0 <= index < numpins).
  165          */
  166         if ((err = resource_int_value(devname, unit, "scl", &sclnum)) != 0)
  167                 sclnum = GPIOIIC_SCL_DFLT;
  168         else if (sclnum < 0 || sclnum >= numpins) {
  169                 device_printf(sc->dev, "invalid scl hint %d\n", sclnum);
  170                 return (EINVAL);
  171         }
  172         if ((err = resource_int_value(devname, unit, "sda", &sdanum)) != 0)
  173                 sdanum = GPIOIIC_SDA_DFLT;
  174         else if (sdanum < 0 || sdanum >= numpins) {
  175                 device_printf(sc->dev, "invalid sda hint %d\n", sdanum);
  176                 return (EINVAL);
  177         }
  178 
  179         /* Allocate gpiobus_pin structs for the pins we found above. */
  180         if ((err = gpio_pin_get_by_child_index(sc->dev, sclnum,
  181             &sc->sclpin)) != 0)
  182                 return (err);
  183         if ((err = gpio_pin_get_by_child_index(sc->dev, sdanum,
  184             &sc->sdapin)) != 0)
  185                 return (err);
  186 
  187         return (0);
  188 }
  189 
  190 static void
  191 gpioiic_setsda(device_t dev, int val)
  192 {
  193         struct gpioiic_softc *sc = device_get_softc(dev);
  194 
  195         if (val) {
  196                 gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT);
  197         } else {
  198                 gpio_pin_setflags(sc->sdapin,
  199                     GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN);
  200                 gpio_pin_set_active(sc->sdapin, 0);
  201         }
  202 }
  203 
  204 static void
  205 gpioiic_setscl(device_t dev, int val)
  206 {
  207         struct gpioiic_softc *sc = device_get_softc(dev);
  208 
  209         if (val) {
  210                 gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT);
  211         } else {
  212                 gpio_pin_setflags(sc->sclpin,
  213                     GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN);
  214                 gpio_pin_set_active(sc->sclpin, 0);
  215         }
  216 }
  217 
  218 static int
  219 gpioiic_getscl(device_t dev)
  220 {
  221         struct gpioiic_softc *sc = device_get_softc(dev);
  222         bool val;
  223 
  224         gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT);
  225         gpio_pin_is_active(sc->sclpin, &val);
  226         return (val);
  227 }
  228 
  229 static int
  230 gpioiic_getsda(device_t dev)
  231 {
  232         struct gpioiic_softc *sc = device_get_softc(dev);
  233         bool val;
  234 
  235         gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT);
  236         gpio_pin_is_active(sc->sdapin, &val);
  237         return (val);
  238 }
  239 
  240 static int
  241 gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
  242 {
  243         struct gpioiic_softc *sc = device_get_softc(dev);
  244 
  245         /* Stop driving the bus pins. */
  246         gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT);
  247         gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT);
  248 
  249         /* Indicate that we have no slave address (master mode). */
  250         return (IIC_ENOADDR);
  251 }
  252 
  253 static void
  254 gpioiic_cleanup(struct gpioiic_softc *sc)
  255 {
  256 
  257         device_delete_children(sc->dev);
  258 
  259         if (sc->sclpin != NULL)
  260                 gpio_pin_release(sc->sclpin);
  261 
  262         if (sc->sdapin != NULL)
  263                 gpio_pin_release(sc->sdapin);
  264 }
  265 
  266 static int
  267 gpioiic_probe(device_t dev)
  268 {
  269         int rv;
  270 
  271         /*
  272          * By default we only bid to attach if specifically added by our parent
  273          * (usually via hint.gpioiic.#.at=busname).  On FDT systems we bid as
  274          * the default driver based on being configured in the FDT data.
  275          */
  276         rv = BUS_PROBE_NOWILDCARD;
  277 
  278 #ifdef FDT
  279         if (ofw_bus_status_okay(dev) &&
  280             ofw_bus_search_compatible(dev, compat_data)->ocd_data)
  281                 rv = BUS_PROBE_DEFAULT;
  282 #endif
  283 
  284         device_set_desc(dev, "GPIO I2C");
  285 
  286         return (rv);
  287 }
  288 
  289 static int
  290 gpioiic_attach(device_t dev)
  291 {
  292         struct gpioiic_softc *sc = device_get_softc(dev);
  293         int err;
  294 
  295         sc->dev = dev;
  296 
  297         /* Acquire our gpio pins. */
  298         err = gpioiic_setup_hinted_pins(sc);
  299 #ifdef FDT
  300         if (err != 0)
  301                 err = gpioiic_setup_fdt_pins(sc);
  302 #endif
  303         if (err != 0) {
  304                 device_printf(sc->dev, "no pins configured\n");
  305                 gpioiic_cleanup(sc);
  306                 return (ENXIO);
  307         }
  308 
  309         /*
  310          * Say what we came up with for pin config.
  311          * NB: in the !FDT case the controller driver might not be set up enough
  312          * for GPIO_GET_BUS() to work.  Also, our parent is the only gpiobus
  313          * that can provide our pins.
  314          */
  315         device_printf(dev, "SCL pin: %s:%d, SDA pin: %s:%d\n",
  316 #ifdef FDT
  317             device_get_nameunit(GPIO_GET_BUS(sc->sclpin->dev)), sc->sclpin->pin,
  318             device_get_nameunit(GPIO_GET_BUS(sc->sdapin->dev)), sc->sdapin->pin);
  319 #else
  320             device_get_nameunit(device_get_parent(dev)), sc->sclpin->pin,
  321             device_get_nameunit(device_get_parent(dev)), sc->sdapin->pin);
  322 #endif
  323 
  324         /* Add the bitbang driver as our only child; it will add iicbus. */
  325         device_add_child(sc->dev, "iicbb", -1);
  326         return (bus_generic_attach(dev));
  327 }
  328 
  329 static int
  330 gpioiic_detach(device_t dev)
  331 {
  332         struct gpioiic_softc *sc = device_get_softc(dev);
  333         int err;
  334 
  335         if ((err = bus_generic_detach(dev)) != 0)
  336                 return (err);
  337 
  338         gpioiic_cleanup(sc);
  339 
  340         return (0);
  341 }
  342 
  343 static device_method_t gpioiic_methods[] = {
  344         /* Device interface */
  345         DEVMETHOD(device_probe,         gpioiic_probe),
  346         DEVMETHOD(device_attach,        gpioiic_attach),
  347         DEVMETHOD(device_detach,        gpioiic_detach),
  348 
  349         /* iicbb interface */
  350         DEVMETHOD(iicbb_setsda,         gpioiic_setsda),
  351         DEVMETHOD(iicbb_setscl,         gpioiic_setscl),
  352         DEVMETHOD(iicbb_getsda,         gpioiic_getsda),
  353         DEVMETHOD(iicbb_getscl,         gpioiic_getscl),
  354         DEVMETHOD(iicbb_reset,          gpioiic_reset),
  355 
  356 #ifdef FDT
  357         /* OFW bus interface */
  358         DEVMETHOD(ofw_bus_get_node,     gpioiic_get_node),
  359 #endif
  360 
  361         DEVMETHOD_END
  362 };
  363 
  364 static driver_t gpioiic_driver = {
  365         "gpioiic",
  366         gpioiic_methods,
  367         sizeof(struct gpioiic_softc),
  368 };
  369 
  370 DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, 0, 0);
  371 DRIVER_MODULE(gpioiic, simplebus, gpioiic_driver, 0, 0);
  372 DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, 0, 0);
  373 MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
  374 MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1);
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FreeBSD/Linux Kernel Cross Reference sys/dev/gpio/gpioiic.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/gpio/gpioiic.c
