smbus: allow child devices to be added via hints
This will allow to add slave drivers in the same fashion as for iicbus. Also, allow other code to add a child device and set its 'addr' ivar. The ivar can only be set if it's unset, it can not be changed. That could be used, for example, by a platform driver that has a precise description of the hardware and, thus, knows what drivers can handle what slaves. The slave auto-probing code is unsafe and broken because it uses 7-bit slave addresses. It's going to be removed. Note: internally the driver uses address of zero as an unset address while smbus_get_addr() returns it as -1 for compatibility reasons. The address is expected to be unset only for children that do not work with slaves like, for example, smb(4). Reviewed by: jhb Differential Revision: https://reviews.freebsd.org/D8173
This commit is contained in:
parent
0e3cfd98fc
commit
94dce59911
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=307130
@ -34,6 +34,10 @@
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#define n(flags) (~(flags) & (flags))
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/* Order constants for smbus children. */
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#define SMBUS_ORDER_HINTED 20
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#define SMBUS_ORDER_PNP 40
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/*
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* How tsleep() is called in smb_request_bus().
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*/
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@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/mutex.h>
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#include <sys/bus.h>
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@ -41,54 +42,16 @@ __FBSDID("$FreeBSD$");
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#include "smbus_if.h"
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#include "bus_if.h"
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struct smbus_ivar
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{
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uint8_t addr;
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};
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/*
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* Autoconfiguration and support routines for System Management bus
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*/
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static void smbus_probe_device(device_t dev, u_char addr);
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/*
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* Device methods
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*/
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static int smbus_probe(device_t);
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static int smbus_attach(device_t);
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static int smbus_detach(device_t);
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static int smbus_child_location_str(device_t parent, device_t child,
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char *buf, size_t buflen);
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static int smbus_print_child(device_t parent, device_t child);
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static void smbus_probe_device(device_t dev, u_char* addr);
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static int smbus_read_ivar(device_t parent, device_t child, int which,
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uintptr_t *result);
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static device_method_t smbus_methods[] = {
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/* device interface */
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DEVMETHOD(device_probe, smbus_probe),
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DEVMETHOD(device_attach, smbus_attach),
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DEVMETHOD(device_detach, smbus_detach),
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/* bus interface */
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DEVMETHOD(bus_add_child, bus_generic_add_child),
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DEVMETHOD(bus_child_location_str, smbus_child_location_str),
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DEVMETHOD(bus_driver_added, bus_generic_driver_added),
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DEVMETHOD(bus_print_child, smbus_print_child),
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DEVMETHOD(bus_read_ivar, smbus_read_ivar),
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DEVMETHOD_END
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};
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driver_t smbus_driver = {
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"smbus",
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smbus_methods,
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sizeof(struct smbus_softc),
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};
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devclass_t smbus_devclass;
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/*
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* At 'probe' time, we add all the devices which we know about to the
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* bus. The generic attach routine will probe and attach them if they
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* are alive.
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*/
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static int
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smbus_probe(device_t dev)
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{
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@ -107,9 +70,9 @@ smbus_attach(device_t dev)
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mtx_init(&sc->lock, device_get_nameunit(dev), "smbus", MTX_DEF);
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bus_generic_probe(dev);
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for (addr = SMBUS_ADDR_MIN; addr < SMBUS_ADDR_MAX; ++addr) {
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sc->addrs[addr] = addr;
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smbus_probe_device(dev, &sc->addrs[addr]);
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smbus_probe_device(dev, addr);
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}
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bus_enumerate_hinted_children(dev);
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bus_generic_attach(dev);
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return (0);
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@ -124,6 +87,7 @@ smbus_detach(device_t dev)
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error = bus_generic_detach(dev);
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if (error)
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return (error);
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device_delete_children(dev);
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mtx_destroy(&sc->lock);
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return (0);
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@ -135,34 +99,78 @@ smbus_generic_intr(device_t dev, u_char devaddr, char low, char high, int err)
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}
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static void
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smbus_probe_device(device_t dev, u_char* addr)
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smbus_probe_device(device_t dev, u_char addr)
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{
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device_t child;
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int error;
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u_char cmd;
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u_char buf[2];
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struct smbus_ivar *devi;
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cmd = 0x01;
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error = smbus_trans(dev, *addr, cmd,
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error = smbus_trans(dev, addr, cmd,
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SMB_TRANS_NOCNT | SMB_TRANS_NOREPORT,
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NULL, 0, buf, 1, NULL);
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if (error == 0) {
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if (bootverbose)
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device_printf(dev, "Probed address 0x%02x\n", *addr);
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child = device_add_child(dev, NULL, -1);
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device_set_ivars(child, addr);
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device_printf(dev, "Probed address 0x%02x\n", addr);
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child = BUS_ADD_CHILD(dev, SMBUS_ORDER_PNP, NULL, -1);
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if (child == NULL)
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return;
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devi = device_get_ivars(child);
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devi->addr = addr;
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}
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}
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static device_t
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smbus_add_child(device_t dev, u_int order, const char *name, int unit)
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{
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struct smbus_ivar *devi;
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device_t child;
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child = device_add_child_ordered(dev, order, name, unit);
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if (child == NULL)
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return (child);
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devi = malloc(sizeof(struct smbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
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if (devi == NULL) {
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device_delete_child(dev, child);
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return (NULL);
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}
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device_set_ivars(child, devi);
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return (child);
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}
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static void
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smbus_hinted_child(device_t bus, const char *dname, int dunit)
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{
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struct smbus_ivar *devi;
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device_t child;
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int addr;
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addr = 0;
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resource_int_value(dname, dunit, "addr", &addr);
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if (addr > UINT8_MAX) {
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device_printf(bus, "ignored incorrect slave address hint 0x%x"
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" for %s%d\n", addr, dname, dunit);
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return;
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}
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child = BUS_ADD_CHILD(bus, SMBUS_ORDER_HINTED, dname, dunit);
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if (child == NULL)
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return;
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devi = device_get_ivars(child);
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devi->addr = addr;
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}
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static int
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smbus_child_location_str(device_t parent, device_t child, char *buf,
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size_t buflen)
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{
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unsigned char *addr;
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struct smbus_ivar *devi;
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addr = device_get_ivars(child);
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if (addr)
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snprintf(buf, buflen, "addr=0x%x", *addr);
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devi = device_get_ivars(child);
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if (devi->addr != 0)
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snprintf(buf, buflen, "addr=0x%x", devi->addr);
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else if (buflen)
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buf[0] = 0;
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return (0);
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@ -171,28 +179,30 @@ smbus_child_location_str(device_t parent, device_t child, char *buf,
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static int
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smbus_print_child(device_t parent, device_t child)
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{
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unsigned char *addr;
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struct smbus_ivar *devi;
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int retval;
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addr = device_get_ivars(child);
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devi = device_get_ivars(child);
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retval = bus_print_child_header(parent, child);
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if (addr)
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retval += printf(" at addr 0x%x", *addr);
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if (devi->addr != 0)
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retval += printf(" at addr 0x%x", devi->addr);
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retval += bus_print_child_footer(parent, child);
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return (retval);
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}
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static int
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smbus_read_ivar(device_t parent, device_t child, int which,
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uintptr_t *result)
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smbus_read_ivar(device_t parent, device_t child, int which, uintptr_t *result)
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{
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unsigned char *addr;
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struct smbus_ivar *devi;
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addr = device_get_ivars(child);
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devi = device_get_ivars(child);
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switch (which) {
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case SMBUS_IVAR_ADDR:
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*result = (addr == NULL) ? -1 : *addr;
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if (devi->addr != 0)
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*result = devi->addr;
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else
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*result = -1;
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break;
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default:
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return (ENOENT);
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@ -200,4 +210,66 @@ smbus_read_ivar(device_t parent, device_t child, int which,
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return (0);
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}
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static int
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smbus_write_ivar(device_t parent, device_t child, int which, uintptr_t value)
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{
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struct smbus_ivar *devi;
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devi = device_get_ivars(child);
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switch (which) {
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case SMBUS_IVAR_ADDR:
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/* Allow to set but no change the slave address. */
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if (devi->addr != 0)
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return (EINVAL);
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devi->addr = value;
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break;
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default:
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return (ENOENT);
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}
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return (0);
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}
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static void
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smbus_probe_nomatch(device_t bus, device_t child)
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{
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struct smbus_ivar *devi = device_get_ivars(child);
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/*
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* Ignore (self-identified) devices without a slave address set.
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* For example, smb(4).
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*/
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if (devi->addr != 0)
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device_printf(bus, "<unknown device> at addr %#x\n",
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devi->addr);
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}
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/*
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* Device methods
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*/
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static device_method_t smbus_methods[] = {
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/* device interface */
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DEVMETHOD(device_probe, smbus_probe),
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DEVMETHOD(device_attach, smbus_attach),
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DEVMETHOD(device_detach, smbus_detach),
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/* bus interface */
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DEVMETHOD(bus_add_child, smbus_add_child),
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DEVMETHOD(bus_hinted_child, smbus_hinted_child),
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DEVMETHOD(bus_probe_nomatch, smbus_probe_nomatch),
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DEVMETHOD(bus_child_location_str, smbus_child_location_str),
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DEVMETHOD(bus_print_child, smbus_print_child),
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DEVMETHOD(bus_read_ivar, smbus_read_ivar),
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DEVMETHOD(bus_write_ivar, smbus_write_ivar),
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DEVMETHOD_END
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};
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driver_t smbus_driver = {
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"smbus",
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smbus_methods,
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sizeof(struct smbus_softc),
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};
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devclass_t smbus_devclass;
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MODULE_VERSION(smbus, SMBUS_MODVER);
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