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Differential D2956 Diff 6583 sys/dev/ow/owc_gpiobus_fdt.c

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sys/dev/ow/owc_gpiobus_fdt.c

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/*-
* Copyright (c) 2015 M. Warner Losh <imp@freebsd.org>
* 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/gpio.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#define FDT 1 /* Can't use this w/o fdt, sorry */
#include <dev/gpio/gpiobusvar.h>
#include "gpiobus_if.h"
#include "owll_if.h"
#define OW_PIN 0
#define OWC_GPIOBUS_FDT_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
#define OWC_GPIOBUS_FDT_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
#define OWC_GPIOBUS_FDT_LOCK_INIT(_sc) \
mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->sc_dev), \
"owc_gpiobus_fdt", MTX_DEF)
#define OWC_GPIOBUS_FDT_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
struct owc_gpiobus_fdt_softc
{
device_t sc_dev;
device_t sc_busdev;
struct mtx sc_mtx;
};
static int owc_gpiobus_fdt_probe(device_t);
static int owc_gpiobus_fdt_attach(device_t);
static int owc_gpiobus_fdt_detach(device_t);
static void
owc_gpiobus_fdt_identify(driver_t *driver, device_t bus)
{
phandle_t w1, root;
/*
*
*/
/*
* Find all the 1-wire bus pseudo-nodes that are
* at the top level of the FDT. Would be nice to
* somehow preserve the node name of these busses,
* but there's no good place to put it. The driver's
* name is used for the device name, and the 1-wire
* bus overwrites the description.
*/
root = OF_finddevice("/");
if (root == 0)
return;
for (w1 = OF_child(root); w1 != 0; w1 = OF_peer(w1)) {
if (!fdt_is_compatible_strict(w1, "w1-gpio"))
continue;
if (!OF_hasprop(w1, "gpios"))
continue;
ofw_gpiobus_add_fdt_child(bus, driver->name, w1);
}
}
static int
owc_gpiobus_fdt_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (ofw_bus_is_compatible(dev, "w1-gpio")) {
device_set_desc(dev, "FDT GPIO attached one-wire bus");
return (BUS_PROBE_DEFAULT);
}
return (ENXIO);
}
static int
owc_gpiobus_fdt_attach(device_t dev)
{
struct owc_gpiobus_fdt_softc *sc;
device_t *kids;
int nkid;
sc = device_get_softc(dev);
sc->sc_dev = dev;
sc->sc_busdev = device_get_parent(dev);
OWC_GPIOBUS_FDT_LOCK_INIT(sc);
nkid = 0;
if (device_get_children(dev, &kids, &nkid) == 0)
free(kids, M_TEMP);
if (nkid == 0)
device_add_child(dev, "ow", -1);
free(kids, M_TEMP);
bus_generic_attach(dev);
return (0);
}
static int
owc_gpiobus_fdt_detach(device_t dev)
{
struct owc_gpiobus_fdt_softc *sc;
sc = device_get_softc(dev);
OWC_GPIOBUS_FDT_LOCK_DESTROY(sc);
bus_generic_detach(dev);
return (0);
}
/*
* In the diagrams below, R is driven by the resitor pullup, M is driven by the
* master, and S is driven by the slave / target.
*/
/* Should come from a table */
#define tLOW1 1
#define tLOW0 60 /* > 60us */
#define tREC 1
#define tSLOT 60 /* 60us to 120us */
#define tLOWR 1
#define tRDV 15
#define tRSTL 480
#define tRSTH 480
#define tPDL 60
#define tPDH 60
/*
* These macros let what why we're doing stuff shine in the code
* below, and let the how be confined to here.
*/
#define GETBUS(sc) GPIOBUS_ACQUIRE_BUS((sc)->sc_busdev, \
(sc)->sc_dev, GPIOBUS_WAIT)
#define RELBUS(sc) GPIOBUS_RELEASE_BUS((sc)->sc_busdev, \
(sc)->sc_dev)
#define OUTPIN(sc) GPIOBUS_PIN_SETFLAGS((sc)->sc_busdev, \
(sc)->sc_dev, OW_PIN, GPIO_PIN_OUTPUT)
#define INPIN(sc) GPIOBUS_PIN_SETFLAGS((sc)->sc_busdev, \
(sc)->sc_dev, OW_PIN, GPIO_PIN_INPUT)
#define GETPIN(sc, bit) GPIOBUS_PIN_GET((sc)->sc_busdev, \
(sc)->sc_dev, OW_PIN, bit)
#define LOW(sc) GPIOBUS_PIN_SET((sc)->sc_busdev, \
(sc)->sc_dev, OW_PIN, GPIO_PIN_LOW)
/*
* WRITE-ONE (see owll_if.m for timings) From Figure 4-1 AN-937
*
* |<---------tSLOT---->|<-tREC->|
* High RRRRM | RRRRRRRRRRRR|RRRRRRRRM
* M | R | | | M
* M| R | | | M
* Low MMMMMMM | | | MMMMMM...
* |<-tLOW1->| | |
* |<------15us--->| |
* |<--------60us---->|
*/
static int
owc_gpiobus_fdt_write_one(device_t dev)
{
struct owc_gpiobus_fdt_softc *sc;
int error;
sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return error;
critical_enter();
/* Force low */
OUTPIN(sc);
LOW(sc);
DELAY(tLOW1);
/* Allow resister to float line high */
INPIN(sc);
DELAY(tSLOT - tLOW1 + tREC);
critical_exit();
RELBUS(sc);
return 0;
}
/*
* WRITE-ZERO (see owll_if.m for timings) From Figure 4-2 AN-937
*
* |<---------tSLOT------>|<-tREC->|
* High RRRRM | | |RRRRRRRM
* M | | R M
* M| | | |R M
* Low MMMMMMMMMMMMMMMMMMMMMR MMMMMM...
* |<--15us->| | |
* |<------60us--->| |
* |<-------tLOW0------>|
*/
static int
owc_gpiobus_fdt_write_zero(device_t dev)
{
struct owc_gpiobus_fdt_softc *sc;
int error;
sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return error;
critical_enter();
/* Force low */
OUTPIN(sc);
LOW(sc);
DELAY(tLOW0);
/* Allow resister to float line high */
INPIN(sc);
DELAY(tSLOT - tLOW0 + tREC);
critical_exit();
RELBUS(sc);
return 0;
}
/*
* READ-DATA (see owll_if.m for timings) From Figure 4-3 AN-937
*
* |<---------tSLOT------>|<-tREC->|
* High RRRRM | rrrrrrrrrrrrrrrRRRRRRRM
* M | r | R M
* M| r | |R M
* Low MMMMMMMSSSSSSSSSSSSSSR MMMMMM...
* |<tLOWR>< sample > |
* |<------tRDV---->| |
* ->| |<-tRELEASE
*
* r -- allowed to pull high via the resitor when slave writes a 1-bit
*
*/
static int
owc_gpiobus_fdt_read_data(device_t dev, int *bit)
{
struct owc_gpiobus_fdt_softc *sc;
int error;
sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return error;
critical_enter();
/* Force low */
OUTPIN(sc);
LOW(sc);
DELAY(tLOWR);
/* Allow resister to float line high or not */
INPIN(sc);
DELAY(tRDV - tLOWR - 3);
/* Read */
GETPIN(sc, bit);
DELAY(tSLOT);
critical_exit();
RELBUS(sc);
return 0;
}
/*
* RESET AND PRESENCE PULSE (see owll_if.m for timings) From Figure 4-4 AN-937
*
* |<---------tRSTH------------>|
* High RRRM | | RRRRRRRS | RRRR RRM
* M | |R| |S | R M
* M| R | | S |R M
* Low MMMMMMMM MMMMMM| | | SSSSSSSSSS MMMMMM
* |<----tRSTL--->| | |<-tPDL---->|
* | ->| |<-tR | |
* |<tPDH>|
*
* Note: for Regular Speed operations, tRSTL + tR should be less than 960us to
* avoid interferring with other devives on the bus
*/
static int
owc_gpiobus_fdt_reset_and_presence(device_t dev, int *bit)
{
struct owc_gpiobus_fdt_softc *sc;
int error;
int buf = -1;
sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return error;
critical_enter();
/* Force low */
OUTPIN(sc);
LOW(sc);
DELAY(tRSTL);
/* Allow resister to float line high and then wait for reset pulse */
INPIN(sc);
DELAY(tPDH + 5);
/* Read presence pulse */
GETPIN(sc, &buf);
critical_exit();
DELAY(tRSTH - (tPDH + 5)); /* Timing not critical for this one */
*bit = !!buf;
RELBUS(sc);
return 0;
}
static devclass_t owc_gpiobus_fdt_devclass;
static device_method_t owc_gpiobus_fdt_methods[] = {
/* Device interface */
DEVMETHOD(device_identify, owc_gpiobus_fdt_identify),
DEVMETHOD(device_probe, owc_gpiobus_fdt_probe),
DEVMETHOD(device_attach, owc_gpiobus_fdt_attach),
DEVMETHOD(device_detach, owc_gpiobus_fdt_detach),
DEVMETHOD(owll_write_one, owc_gpiobus_fdt_write_one),
DEVMETHOD(owll_write_zero, owc_gpiobus_fdt_write_zero),
DEVMETHOD(owll_read_data, owc_gpiobus_fdt_read_data),
DEVMETHOD(owll_reset_and_presence, owc_gpiobus_fdt_reset_and_presence),
{ 0, 0 }
};
static driver_t owc_gpiobus_fdt_driver = {
"owc",
owc_gpiobus_fdt_methods,
sizeof(struct owc_gpiobus_fdt_softc),
};
DRIVER_MODULE(owc_gpiobus_fdt, gpiobus, owc_gpiobus_fdt_driver, owc_gpiobus_fdt_devclass, 0, 0);
MODULE_DEPEND(owc_gpiobus_fdt, ow, 1, 1, 1);