lpbb.c

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    1 /*-
    2  * Copyright (c) 1998, 2001 Nicolas Souchu, Marc Bouget
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  *
   26  *
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD$");
   31 
   32 /*
   33  * I2C Bit-Banging over parallel port
   34  *
   35  * See the Official Philips interface description in lpbb(4)
   36  */
   37 
   38 #include <sys/param.h>
   39 #include <sys/bus.h>
   40 #include <sys/lock.h>
   41 #include <sys/kernel.h>
   42 #include <sys/module.h>
   43 #include <sys/mutex.h>
   44 #include <sys/systm.h>
   45 #include <sys/uio.h>
   46 
   47 
   48 #include <dev/ppbus/ppbconf.h>
   49 #include "ppbus_if.h"
   50 #include <dev/ppbus/ppbio.h>
   51 
   52 #include <dev/iicbus/iiconf.h>
   53 #include <dev/iicbus/iicbus.h>
   54 
   55 #include "iicbb_if.h"
   56 
   57 static int lpbb_detect(device_t dev);
   58 
   59 static void
   60 lpbb_identify(driver_t *driver, device_t parent)
   61 {
   62 
   63         device_t dev;
   64 
   65         dev = device_find_child(parent, "lpbb", -1);
   66         if (!dev)
   67                 BUS_ADD_CHILD(parent, 0, "lpbb", -1);
   68 }
   69 
   70 static int
   71 lpbb_probe(device_t dev)
   72 {
   73 
   74         /* Perhaps call this during identify instead? */
   75         if (!lpbb_detect(dev))
   76                 return (ENXIO);
   77 
   78         device_set_desc(dev, "Parallel I2C bit-banging interface");
   79 
   80         return (0);
   81 }
   82 
   83 static int
   84 lpbb_attach(device_t dev)
   85 {
   86         device_t bitbang;
   87 
   88         /* add generic bit-banging code */
   89         bitbang = device_add_child(dev, "iicbb", -1);
   90         device_probe_and_attach(bitbang);
   91 
   92         return (0);
   93 }
   94 
   95 static int
   96 lpbb_callback(device_t dev, int index, caddr_t data)
   97 {
   98         device_t ppbus = device_get_parent(dev);
   99         int error = 0;
  100         int how;
  101 
  102         switch (index) {
  103         case IIC_REQUEST_BUS:
  104                 /* request the ppbus */
  105                 how = *(int *)data;
  106                 ppb_lock(ppbus);
  107                 error = ppb_request_bus(ppbus, dev, how);
  108                 ppb_unlock(ppbus);
  109                 break;
  110 
  111         case IIC_RELEASE_BUS:
  112                 /* release the ppbus */
  113                 ppb_lock(ppbus);
  114                 error = ppb_release_bus(ppbus, dev);
  115                 ppb_unlock(ppbus);
  116                 break;
  117 
  118         default:
  119                 error = EINVAL;
  120         }
  121 
  122         return (error);
  123 }
  124 
  125 #define SDA_out 0x80
  126 #define SCL_out 0x08
  127 #define SDA_in  0x80
  128 #define SCL_in  0x08
  129 #define ALIM    0x20
  130 #define I2CKEY  0x50
  131 
  132 /* Reset bus by setting SDA first and then SCL. */
  133 static void
  134 lpbb_reset_bus(device_t dev)
  135 {
  136         device_t ppbus = device_get_parent(dev);
  137 
  138         ppb_assert_locked(ppbus);
  139         ppb_wdtr(ppbus, (u_char)~SDA_out);
  140         ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus) | SCL_out));
  141 }
  142 
  143 static int
  144 lpbb_getscl(device_t dev)
  145 {
  146         device_t ppbus = device_get_parent(dev);
  147         int rval;
  148 
  149         ppb_lock(ppbus);
  150         rval = ((ppb_rstr(ppbus) & SCL_in) == SCL_in);
  151         ppb_unlock(ppbus);
  152         return (rval);
  153 }
  154 
  155 static int
  156 lpbb_getsda(device_t dev)
  157 {
  158         device_t ppbus = device_get_parent(dev);
  159         int rval;
  160 
  161         ppb_lock(ppbus);
  162         rval = ((ppb_rstr(ppbus) & SDA_in) == SDA_in);
  163         ppb_unlock(ppbus);
  164         return (rval);
  165 }
  166 
  167 static void
  168 lpbb_setsda(device_t dev, int val)
  169 {
  170         device_t ppbus = device_get_parent(dev);
  171 
  172         ppb_lock(ppbus);
  173         if (val == 0)
  174                 ppb_wdtr(ppbus, (u_char)SDA_out);
  175         else
  176                 ppb_wdtr(ppbus, (u_char)~SDA_out);
  177         ppb_unlock(ppbus);
  178 }
  179 
  180 static void
  181 lpbb_setscl(device_t dev, int val)
  182 {
  183         device_t ppbus = device_get_parent(dev);
  184 
  185         ppb_lock(ppbus);
  186         if (val == 0)
  187                 ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus) & ~SCL_out));
  188         else
  189                 ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus) | SCL_out));
  190         ppb_unlock(ppbus);
  191 }
  192 
  193 static int
  194 lpbb_detect(device_t dev)
  195 {
  196         device_t ppbus = device_get_parent(dev);
  197 
  198         ppb_lock(ppbus);
  199         if (ppb_request_bus(ppbus, dev, PPB_DONTWAIT)) {
  200                 ppb_unlock(ppbus);
  201                 device_printf(dev, "can't allocate ppbus\n");
  202                 return (0);
  203         }
  204 
  205         lpbb_reset_bus(dev);
  206 
  207         if ((ppb_rstr(ppbus) & I2CKEY) ||
  208                 ((ppb_rstr(ppbus) & ALIM) != ALIM)) {
  209                 ppb_release_bus(ppbus, dev);
  210                 ppb_unlock(ppbus);
  211                 return (0);
  212         }
  213 
  214         ppb_release_bus(ppbus, dev);
  215         ppb_unlock(ppbus);
  216 
  217         return (1);
  218 }
  219 
  220 static int
  221 lpbb_reset(device_t dev, u_char speed, u_char addr, u_char * oldaddr)
  222 {
  223         device_t ppbus = device_get_parent(dev);
  224 
  225         ppb_lock(ppbus);
  226         if (ppb_request_bus(ppbus, dev, PPB_DONTWAIT)) {
  227                 ppb_unlock(ppbus);
  228                 device_printf(dev, "can't allocate ppbus\n");
  229                 return (0);
  230         }
  231 
  232         lpbb_reset_bus(dev);
  233 
  234         ppb_release_bus(ppbus, dev);
  235         ppb_unlock(ppbus);
  236 
  237         return (IIC_ENOADDR);
  238 }
  239 
  240 static devclass_t lpbb_devclass;
  241 
  242 static device_method_t lpbb_methods[] = {
  243         /* device interface */
  244         DEVMETHOD(device_identify,      lpbb_identify),
  245         DEVMETHOD(device_probe,         lpbb_probe),
  246         DEVMETHOD(device_attach,        lpbb_attach),
  247 
  248         /* iicbb interface */
  249         DEVMETHOD(iicbb_callback,       lpbb_callback),
  250         DEVMETHOD(iicbb_setsda,         lpbb_setsda),
  251         DEVMETHOD(iicbb_setscl,         lpbb_setscl),
  252         DEVMETHOD(iicbb_getsda,         lpbb_getsda),
  253         DEVMETHOD(iicbb_getscl,         lpbb_getscl),
  254         DEVMETHOD(iicbb_reset,          lpbb_reset),
  255 
  256         DEVMETHOD_END
  257 };
  258 
  259 static driver_t lpbb_driver = {
  260         "lpbb",
  261         lpbb_methods,
  262         1,
  263 };
  264 
  265 DRIVER_MODULE(lpbb, ppbus, lpbb_driver, lpbb_devclass, 0, 0);
  266 DRIVER_MODULE(iicbb, lpbb, iicbb_driver, iicbb_devclass, 0, 0);
  267 MODULE_DEPEND(lpbb, ppbus, 1, 1, 1);
  268 MODULE_DEPEND(lpbb, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
  269 MODULE_VERSION(lpbb, 1);

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FreeBSD/Linux Kernel Cross Reference sys/dev/ppbus/lpbb.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/ppbus/lpbb.c