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

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 1998, 2001 Nicolas Souchu
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    /*
     * Autoconfiguration and support routines for the Philips serial I2C bus
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/bus.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/module.h>
    #include <sys/mutex.h>
    #include <sys/rman.h>
    #include <sys/sbuf.h>
    #include <sys/sysctl.h>
    
    #include <dev/iicbus/iiconf.h>
    #include <dev/iicbus/iicbus.h>
    
    #include "iicbus_if.h"
    
    /* See comments below for why auto-scanning is a bad idea. */
    #define SCAN_IICBUS 0
    
    SYSCTL_NODE(_hw, OID_AUTO, i2c, CTLFLAG_RW, 0, "i2c controls");
    
    static int
    iicbus_probe(device_t dev)
    {
    
            device_set_desc(dev, "Philips I2C bus");
    
            /* Allow other subclasses to override this driver. */
            return (BUS_PROBE_GENERIC);
    }
    
    #if SCAN_IICBUS
    static int
    iic_probe_device(device_t dev, u_char addr)
    {
            int count;
            char byte;
    
            if ((addr & 1) == 0) {
                    /* is device writable? */
                    if (!iicbus_start(dev, (u_char)addr, 0)) {
                            iicbus_stop(dev);
                            return (1);
                    }
            } else {
                    /* is device readable? */
                    if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
                            return (1);
            }
    
            return (0);
    }
    #endif
    
    /*
     * We add all the devices which we know about.
     * The generic attach routine will attach them if they are alive.
     */
    int
    iicbus_attach_common(device_t dev, u_int bus_freq)
    {
    #if SCAN_IICBUS
            unsigned char addr;
   #endif
           struct iicbus_softc *sc = IICBUS_SOFTC(dev);
           int strict;
   
           sc->dev = dev;
           mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
           iicbus_init_frequency(dev, bus_freq);
           iicbus_reset(dev, IIC_FASTEST, 0, NULL);
           if (resource_int_value(device_get_name(dev),
                   device_get_unit(dev), "strict", &strict) == 0)
                   sc->strict = strict;
           else
                   sc->strict = 1;
   
           /* device probing is meaningless since the bus is supposed to be
            * hot-plug. Moreover, some I2C chips do not appreciate random
            * accesses like stop after start to fast, reads for less than
            * x bytes...
            */
   #if SCAN_IICBUS
           printf("Probing for devices on iicbus%d:", device_get_unit(dev));
   
           /* probe any devices */
           for (addr = 16; addr < 240; addr++) {
                   if (iic_probe_device(dev, (u_char)addr)) {
                           printf(" <%x>", addr);
                   }
           }
           printf("\n");
   #endif
           bus_generic_probe(dev);
           bus_enumerate_hinted_children(dev);
           bus_generic_attach(dev);
           return (0);
   }
   
   static int
   iicbus_attach(device_t dev)
   {
   
           return (iicbus_attach_common(dev, 0));
   }
   
   int
   iicbus_detach(device_t dev)
   {
           struct iicbus_softc *sc = IICBUS_SOFTC(dev);
           int err;
   
           if ((err = device_delete_children(dev)) != 0)
                   return (err);
           iicbus_reset(dev, IIC_FASTEST, 0, NULL);
           mtx_destroy(&sc->lock);
           return (0);
   }
   
   static int
   iicbus_print_child(device_t dev, device_t child)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
           int retval = 0;
   
           retval += bus_print_child_header(dev, child);
           if (devi->addr != 0)
                   retval += printf(" at addr %#x", devi->addr);
           resource_list_print_type(&devi->rl, "irq", SYS_RES_IRQ, "%jd");
           retval += bus_print_child_footer(dev, child);
   
           return (retval);
   }
   
   void
   iicbus_probe_nomatch(device_t bus, device_t child)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           device_printf(bus, "<unknown card> at addr %#x\n", devi->addr);
   }
   
   int
   iicbus_child_location(device_t bus, device_t child, struct sbuf *sb)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           sbuf_printf(sb, "addr=%#x", devi->addr);
           return (0);
   }
   
   int
   iicbus_child_pnpinfo(device_t bus, device_t child, struct sbuf *sb)
   {
           return (0);
   }
   
   int
   iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           switch (which) {
           default:
                   return (EINVAL);
           case IICBUS_IVAR_ADDR:
                   *result = devi->addr;
                   break;
           }
           return (0);
   }
   
   int
   iicbus_write_ivar(device_t bus, device_t child, int which, uintptr_t value)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           switch (which) {
           default:
                   return (EINVAL);
           case IICBUS_IVAR_ADDR:
                   if (devi->addr != 0)
                           return (EINVAL);
                   devi->addr = value;
           }
           return (0);
   }
   
   device_t
   iicbus_add_child_common(device_t dev, u_int order, const char *name, int unit,
       size_t ivars_size)
   {
           device_t child;
           struct iicbus_ivar *devi;
   
           child = device_add_child_ordered(dev, order, name, unit);
           if (child == NULL)
                   return (child);
           devi = malloc(ivars_size, M_DEVBUF, M_NOWAIT | M_ZERO);
           if (devi == NULL) {
                   device_delete_child(dev, child);
                   return (0);
           }
           resource_list_init(&devi->rl);
           device_set_ivars(child, devi);
           return (child);
   }
   
   static device_t
   iicbus_add_child(device_t dev, u_int order, const char *name, int unit)
   {
   
           return (iicbus_add_child_common(
               dev, order, name, unit, sizeof(struct iicbus_ivar)));
   }
   
   static void
   iicbus_hinted_child(device_t bus, const char *dname, int dunit)
   {
           device_t child;
           int irq;
           struct iicbus_ivar *devi;
   
           child = BUS_ADD_CHILD(bus, 0, dname, dunit);
           devi = IICBUS_IVAR(child);
           resource_int_value(dname, dunit, "addr", &devi->addr);
           if (resource_int_value(dname, dunit, "irq", &irq) == 0) {
                   if (bus_set_resource(child, SYS_RES_IRQ, 0, irq, 1) != 0)
                           device_printf(bus,
                               "warning: bus_set_resource() failed\n");
           }
   }
   
   static struct resource_list *
   iicbus_get_resource_list(device_t bus __unused, device_t child)
   {
           struct iicbus_ivar *devi;
   
           devi = IICBUS_IVAR(child);
           return (&devi->rl);
   }
   
   int
   iicbus_generic_intr(device_t dev, int event, char *buf)
   {
   
           return (0);
   }
   
   int
   iicbus_null_callback(device_t dev, int index, caddr_t data)
   {
   
           return (0);
   }
   
   int
   iicbus_null_repeated_start(device_t dev, u_char addr)
   {
   
           return (IIC_ENOTSUPP);
   }
   
   void
   iicbus_init_frequency(device_t dev, u_int bus_freq)
   {
           struct iicbus_softc *sc = IICBUS_SOFTC(dev);
   
           /*
            * If a bus frequency value was passed in, use it.  Otherwise initialize
            * it first to the standard i2c 100KHz frequency, then override that
            * from a hint if one exists.
            */
           if (bus_freq > 0)
                   sc->bus_freq = bus_freq;
           else {
                   sc->bus_freq = 100000;
                   resource_int_value(device_get_name(dev), device_get_unit(dev),
                       "frequency", (int *)&sc->bus_freq);
           }
           /*
            * Set up the sysctl that allows the bus frequency to be changed.
            * It is flagged as a tunable so that the user can set the value in
            * loader(8), and that will override any other setting from any source.
            * The sysctl tunable/value is the one most directly controlled by the
            * user and thus the one that always takes precedence.
            */
           SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
               SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
               OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
               sc->bus_freq, "Bus frequency in Hz");
   }
   
   static u_int
   iicbus_get_frequency(device_t dev, u_char speed)
   {
           struct iicbus_softc *sc = IICBUS_SOFTC(dev);
   
           /*
            * If the frequency has not been configured for the bus, or the request
            * is specifically for SLOW speed, use the standard 100KHz rate, else
            * use the configured bus speed.
            */
           if (sc->bus_freq == 0 || speed == IIC_SLOW)
                   return (100000);
           return (sc->bus_freq);
   }
   
   static device_method_t iicbus_methods[] = {
           /* device interface */
           DEVMETHOD(device_probe,         iicbus_probe),
           DEVMETHOD(device_attach,        iicbus_attach),
           DEVMETHOD(device_detach,        iicbus_detach),
           DEVMETHOD(device_suspend,       bus_generic_suspend),
           DEVMETHOD(device_resume,        bus_generic_resume),
   
           /* bus interface */
           DEVMETHOD(bus_setup_intr,       bus_generic_setup_intr),
           DEVMETHOD(bus_teardown_intr,    bus_generic_teardown_intr),
           DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
           DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
           DEVMETHOD(bus_adjust_resource,  bus_generic_adjust_resource),
           DEVMETHOD(bus_alloc_resource,   bus_generic_rl_alloc_resource),
           DEVMETHOD(bus_get_resource,     bus_generic_rl_get_resource),
           DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
           DEVMETHOD(bus_set_resource,     bus_generic_rl_set_resource),
           DEVMETHOD(bus_get_resource_list, iicbus_get_resource_list),
           DEVMETHOD(bus_add_child,        iicbus_add_child),
           DEVMETHOD(bus_print_child,      iicbus_print_child),
           DEVMETHOD(bus_probe_nomatch,    iicbus_probe_nomatch),
           DEVMETHOD(bus_read_ivar,        iicbus_read_ivar),
           DEVMETHOD(bus_write_ivar,       iicbus_write_ivar),
           DEVMETHOD(bus_child_pnpinfo,    iicbus_child_pnpinfo),
           DEVMETHOD(bus_child_location,   iicbus_child_location),
           DEVMETHOD(bus_hinted_child,     iicbus_hinted_child),
   
           /* iicbus interface */
           DEVMETHOD(iicbus_transfer,      iicbus_transfer),
           DEVMETHOD(iicbus_get_frequency, iicbus_get_frequency),
   
           DEVMETHOD_END
   };
   
   driver_t iicbus_driver = {
           "iicbus",
           iicbus_methods,
           sizeof(struct iicbus_softc),
   };
   
   MODULE_VERSION(iicbus, IICBUS_MODVER);
   DRIVER_MODULE(iicbus, iichb, iicbus_driver, 0, 0);

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