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head/sys/dev/ow/owc_gpiobus.c

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#include <sys/bus.h> #include <sys/bus.h>
#include <sys/gpio.h> #include <sys/gpio.h>
#include <sys/kernel.h> #include <sys/kernel.h>
#include <sys/lock.h> #include <sys/lock.h>
#include <sys/malloc.h> #include <sys/malloc.h>
#include <sys/module.h> #include <sys/module.h>
#include <sys/mutex.h> #include <sys/mutex.h>
#include <dev/gpio/gpiobusvar.h>
#include <dev/ow/owll.h>
#ifdef FDT #ifdef FDT
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h> #include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h> #include <dev/ofw/ofw_bus_subr.h>
#endif
#include <dev/gpio/gpiobusvar.h> static struct ofw_compat_data compat_data[] = {
#include "gpiobus_if.h" {"w1-gpio", true},
{NULL, false}
};
OFWBUS_PNP_INFO(compat_data);
SIMPLEBUS_PNP_INFO(compat_data);
#endif /* FDT */
#include <dev/ow/owll.h>
#define OW_PIN 0 #define OW_PIN 0
#define OWC_GPIOBUS_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx) #define OWC_GPIOBUS_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
#define OWC_GPIOBUS_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx) #define OWC_GPIOBUS_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
#define OWC_GPIOBUS_LOCK_INIT(_sc) \ #define OWC_GPIOBUS_LOCK_INIT(_sc) \
mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->sc_dev), \ mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->sc_dev), \
"owc_gpiobus", MTX_DEF) "owc_gpiobus", MTX_DEF)
#define OWC_GPIOBUS_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx); #define OWC_GPIOBUS_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
struct owc_gpiobus_softc struct owc_gpiobus_softc
{ {
device_t sc_dev; device_t sc_dev;
device_t sc_busdev; gpio_pin_t sc_pin;
struct mtx sc_mtx; struct mtx sc_mtx;
}; };
static int owc_gpiobus_probe(device_t); static int owc_gpiobus_probe(device_t);
static int owc_gpiobus_attach(device_t); static int owc_gpiobus_attach(device_t);
static int owc_gpiobus_detach(device_t); static int owc_gpiobus_detach(device_t);
#ifdef FDT static int
static void owc_gpiobus_probe(device_t dev)
owc_gpiobus_identify(driver_t *driver, device_t bus)
{ {
phandle_t w1, root; int rv;
/* /*
* Find all the 1-wire bus pseudo-nodes that are * By default we only bid to attach if specifically added by our parent
* at the top level of the FDT. Would be nice to * (usually via hint.owc_gpiobus.#.at=busname). On FDT systems we bid
* somehow preserve the node name of these busses, * as the default driver based on being configured in the FDT data.
* 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("/"); rv = BUS_PROBE_NOWILDCARD;
if (root == -1)
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);
}
}
#endif
static int
owc_gpiobus_probe(device_t dev)
{
#ifdef FDT #ifdef FDT
if (!ofw_bus_status_okay(dev)) if (ofw_bus_status_okay(dev) &&
return (ENXIO); ofw_bus_search_compatible(dev, compat_data)->ocd_data)
rv = BUS_PROBE_DEFAULT;
#endif
if (ofw_bus_is_compatible(dev, "w1-gpio")) { device_set_desc(dev, "GPIO one-wire bus");
device_set_desc(dev, "FDT GPIO attached one-wire bus");
return (BUS_PROBE_DEFAULT);
}
return (ENXIO); return (rv);
#else
device_set_desc(dev, "GPIO attached one-wire bus");
return 0;
#endif
} }
static int static int
owc_gpiobus_attach(device_t dev) owc_gpiobus_attach(device_t dev)
{ {
struct owc_gpiobus_softc *sc; struct owc_gpiobus_softc *sc;
device_t *kids; int err;
int nkid;
sc = device_get_softc(dev); sc = device_get_softc(dev);
sc->sc_dev = dev; sc->sc_dev = dev;
sc->sc_busdev = device_get_parent(dev);
#ifdef FDT
/* Try to configure our pin from fdt data on fdt-based systems. */
err = gpio_pin_get_by_ofw_idx(dev, ofw_bus_get_node(dev), OW_PIN,
&sc->sc_pin);
#else
err = ENOENT;
#endif
/*
* If we didn't get configured by fdt data and our parent is gpiobus,
* see if we can be configured by the bus (allows hinted attachment even
* on fdt-based systems).
*/
if (err != 0 &&
strcmp("gpiobus", device_get_name(device_get_parent(dev))) == 0)
err = gpio_pin_get_by_child_index(dev, OW_PIN, &sc->sc_pin);
/* If we didn't get configured by either method, whine and punt. */
if (err != 0) {
device_printf(sc->sc_dev,
"cannot acquire gpio pin (config error)\n");
return (err);
}
OWC_GPIOBUS_LOCK_INIT(sc); OWC_GPIOBUS_LOCK_INIT(sc);
nkid = 0;
if (device_get_children(dev, &kids, &nkid) == 0) /*
free(kids, M_TEMP); * Add the ow bus as a child, but defer probing and attaching it until
if (nkid == 0) * interrupts work, because we can't do IO for them until we can read
device_add_child(dev, "ow", -1); * the system timecounter (which initializes after device attachments).
*/
device_add_child(sc->sc_dev, "ow", -1);
return (bus_delayed_attach_children(dev)); return (bus_delayed_attach_children(dev));
} }
static int static int
owc_gpiobus_detach(device_t dev) owc_gpiobus_detach(device_t dev)
{ {
struct owc_gpiobus_softc *sc; struct owc_gpiobus_softc *sc;
int err;
sc = device_get_softc(dev); sc = device_get_softc(dev);
if ((err = device_delete_children(dev)) != 0)
return (err);
gpio_pin_release(sc->sc_pin);
OWC_GPIOBUS_LOCK_DESTROY(sc); OWC_GPIOBUS_LOCK_DESTROY(sc);
bus_generic_detach(dev);
return (0); return (0);
} }
/* /*
* In the diagrams below, R is driven by the resistor pullup, M is driven by the * In the diagrams below, R is driven by the resistor pullup, M is driven by the
* master, and S is driven by the slave / target. * master, and S is driven by the slave / target.
*/ */
/* /*
* These macros let what why we're doing stuff shine in the code * These macros let what why we're doing stuff shine in the code
* below, and let the how be confined to here. * below, and let the how be confined to here.
*/ */
#define GETBUS(sc) GPIOBUS_ACQUIRE_BUS((sc)->sc_busdev, \ #define OUTPIN(sc) gpio_pin_setflags((sc)->sc_pin, GPIO_PIN_OUTPUT)
(sc)->sc_dev, GPIOBUS_WAIT) #define INPIN(sc) gpio_pin_setflags((sc)->sc_pin, GPIO_PIN_INPUT)
#define RELBUS(sc) GPIOBUS_RELEASE_BUS((sc)->sc_busdev, \ #define GETPIN(sc, bp) gpio_pin_is_active((sc)->sc_pin, (bp))
(sc)->sc_dev) #define LOW(sc) gpio_pin_set_active((sc)->sc_pin, false)
#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 * WRITE-ONE (see owll_if.m for timings) From Figure 4-1 AN-937
* *
* |<---------tSLOT---->|<-tREC->| * |<---------tSLOT---->|<-tREC->|
* High RRRRM | RRRRRRRRRRRR|RRRRRRRRM * High RRRRM | RRRRRRRRRRRR|RRRRRRRRM
* M | R | | | M * M | R | | | M
* M| R | | | M * M| R | | | M
* Low MMMMMMM | | | MMMMMM... * Low MMMMMMM | | | MMMMMM...
* |<-tLOW1->| | | * |<-tLOW1->| | |
* |<------15us--->| | * |<------15us--->| |
* |<--------60us---->| * |<--------60us---->|
*/ */
static int static int
owc_gpiobus_write_one(device_t dev, struct ow_timing *t) owc_gpiobus_write_one(device_t dev, struct ow_timing *t)
{ {
struct owc_gpiobus_softc *sc; struct owc_gpiobus_softc *sc;
int error;
sc = device_get_softc(dev); sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return (error);
critical_enter(); critical_enter();
/* Force low */ /* Force low */
OUTPIN(sc); OUTPIN(sc);
LOW(sc); LOW(sc);
DELAY(t->t_low1); DELAY(t->t_low1);
/* Allow resistor to float line high */ /* Allow resistor to float line high */
INPIN(sc); INPIN(sc);
DELAY(t->t_slot - t->t_low1 + t->t_rec); DELAY(t->t_slot - t->t_low1 + t->t_rec);
critical_exit(); critical_exit();
RELBUS(sc);
return (0); return (0);
} }
/* /*
* WRITE-ZERO (see owll_if.m for timings) From Figure 4-2 AN-937 * WRITE-ZERO (see owll_if.m for timings) From Figure 4-2 AN-937
* *
* |<---------tSLOT------>|<-tREC->| * |<---------tSLOT------>|<-tREC->|
* High RRRRM | | |RRRRRRRM * High RRRRM | | |RRRRRRRM
* M | | R M * M | | R M
* M| | | |R M * M| | | |R M
* Low MMMMMMMMMMMMMMMMMMMMMR MMMMMM... * Low MMMMMMMMMMMMMMMMMMMMMR MMMMMM...
* |<--15us->| | | * |<--15us->| | |
* |<------60us--->| | * |<------60us--->| |
* |<-------tLOW0------>| * |<-------tLOW0------>|
*/ */
static int static int
owc_gpiobus_write_zero(device_t dev, struct ow_timing *t) owc_gpiobus_write_zero(device_t dev, struct ow_timing *t)
{ {
struct owc_gpiobus_softc *sc; struct owc_gpiobus_softc *sc;
int error;
sc = device_get_softc(dev); sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return (error);
critical_enter(); critical_enter();
/* Force low */ /* Force low */
OUTPIN(sc); OUTPIN(sc);
LOW(sc); LOW(sc);
DELAY(t->t_low0); DELAY(t->t_low0);
/* Allow resistor to float line high */ /* Allow resistor to float line high */
INPIN(sc); INPIN(sc);
DELAY(t->t_slot - t->t_low0 + t->t_rec); DELAY(t->t_slot - t->t_low0 + t->t_rec);
critical_exit(); critical_exit();
RELBUS(sc);
return (0); return (0);
} }
/* /*
* READ-DATA (see owll_if.m for timings) From Figure 4-3 AN-937 * READ-DATA (see owll_if.m for timings) From Figure 4-3 AN-937
* *
* |<---------tSLOT------>|<-tREC->| * |<---------tSLOT------>|<-tREC->|
* High RRRRM | rrrrrrrrrrrrrrrRRRRRRRM * High RRRRM | rrrrrrrrrrrrrrrRRRRRRRM
* M | r | R M * M | r | R M
* M| r | |R M * M| r | |R M
* Low MMMMMMMSSSSSSSSSSSSSSR MMMMMM... * Low MMMMMMMSSSSSSSSSSSSSSR MMMMMM...
* |<tLOWR>< sample > | * |<tLOWR>< sample > |
* |<------tRDV---->| | * |<------tRDV---->| |
* ->| |<-tRELEASE * ->| |<-tRELEASE
* *
* r -- allowed to pull high via the resitor when slave writes a 1-bit * r -- allowed to pull high via the resitor when slave writes a 1-bit
* *
*/ */
static int static int
owc_gpiobus_read_data(device_t dev, struct ow_timing *t, int *bit) owc_gpiobus_read_data(device_t dev, struct ow_timing *t, int *bit)
{ {
struct owc_gpiobus_softc *sc; struct owc_gpiobus_softc *sc;
int error, sample; bool sample;
sbintime_t then, now; sbintime_t then, now;
sc = device_get_softc(dev); sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return (error);
critical_enter(); critical_enter();
/* Force low for t_lowr microseconds */ /* Force low for t_lowr microseconds */
then = sbinuptime(); then = sbinuptime();
OUTPIN(sc); OUTPIN(sc);
LOW(sc); LOW(sc);
DELAY(t->t_lowr); DELAY(t->t_lowr);
/* /*
* Slave is supposed to hold the line low for t_rdv microseconds for 0 * Slave is supposed to hold the line low for t_rdv microseconds for 0
* and immediately float it high for a 1. This is measured from the * and immediately float it high for a 1. This is measured from the
* master's pushing the line low. * master's pushing the line low.
*/ */
INPIN(sc); INPIN(sc);
do { do {
now = sbinuptime(); now = sbinuptime();
GETPIN(sc, &sample); GETPIN(sc, &sample);
} while (now - then < (t->t_rdv + 2) * SBT_1US && sample == 0); } while (now - then < (t->t_rdv + 2) * SBT_1US && sample == false);
critical_exit(); critical_exit();
if (now - then < t->t_rdv * SBT_1US) if (now - then < t->t_rdv * SBT_1US)
*bit = 1; *bit = 1;
else else
*bit = 0; *bit = 0;
/* Wait out the rest of t_slot */ /* Wait out the rest of t_slot */
do { do {
now = sbinuptime(); now = sbinuptime();
} while (now - then < (t->t_slot + t->t_rec) * SBT_1US); } while (now - then < (t->t_slot + t->t_rec) * SBT_1US);
RELBUS(sc); return (0);
return (error);
} }
/* /*
* RESET AND PRESENCE PULSE (see owll_if.m for timings) From Figure 4-4 AN-937 * RESET AND PRESENCE PULSE (see owll_if.m for timings) From Figure 4-4 AN-937
* *
* |<---------tRSTH------------>| * |<---------tRSTH------------>|
* High RRRM | | RRRRRRRS | RRRR RRM * High RRRM | | RRRRRRRS | RRRR RRM
* M | |R| |S | R M * M | |R| |S | R M
* M| R | | S |R M * M| R | | S |R M
* Low MMMMMMMM MMMMMM| | | SSSSSSSSSS MMMMMM * Low MMMMMMMM MMMMMM| | | SSSSSSSSSS MMMMMM
* |<----tRSTL--->| | |<-tPDL---->| * |<----tRSTL--->| | |<-tPDL---->|
* | ->| |<-tR | | * | ->| |<-tR | |
* |<tPDH>| * |<tPDH>|
* *
* Note: for Regular Speed operations, tRSTL + tR should be less than 960us to * Note: for Regular Speed operations, tRSTL + tR should be less than 960us to
* avoid interferring with other devices on the bus * avoid interfering with other devices on the bus.
*
* Return values in *bit:
* -1 = Bus wiring error (stuck low).
* 0 = no presence pulse
* 1 = presence pulse detected
*/ */
static int static int
owc_gpiobus_reset_and_presence(device_t dev, struct ow_timing *t, int *bit) owc_gpiobus_reset_and_presence(device_t dev, struct ow_timing *t, int *bit)
{ {
struct owc_gpiobus_softc *sc; struct owc_gpiobus_softc *sc;
int error; bool sample;
int buf = -1;
sc = device_get_softc(dev); sc = device_get_softc(dev);
error = GETBUS(sc);
if (error != 0)
return (error);
/* /*
* Read the current state of the bus. The steady state of an idle bus is * Read the current state of the bus. The steady state of an idle bus is
* high. Badly wired buses that are missing the required pull up, or * high. Badly wired buses that are missing the required pull up, or
* that have a short circuit to ground cause all kinds of mischief when * that have a short circuit to ground cause all kinds of mischief when
* we try to read them later. Return EIO and release the bus if the bus * we try to read them later. Return EIO if the bus is currently low.
* is currently low.
*/ */
INPIN(sc); INPIN(sc);
GETPIN(sc, &buf); GETPIN(sc, &sample);
if (buf == 0) { if (sample == false) {
*bit = -1; *bit = -1;
RELBUS(sc);
return (EIO); return (EIO);
} }
critical_enter(); critical_enter();
/* Force low */ /* Force low */
OUTPIN(sc); OUTPIN(sc);
LOW(sc); LOW(sc);
DELAY(t->t_rstl); DELAY(t->t_rstl);
/* Allow resistor to float line high and then wait for reset pulse */ /* Allow resistor to float line high and then wait for reset pulse */
INPIN(sc); INPIN(sc);
DELAY(t->t_pdh + t->t_pdl / 2); DELAY(t->t_pdh + t->t_pdl / 2);
/* Read presence pulse */ /* Read presence pulse */
GETPIN(sc, &buf); GETPIN(sc, &sample);
*bit = !!buf; *bit = sample;
critical_exit(); critical_exit();
DELAY(t->t_rsth - (t->t_pdh + t->t_pdl / 2)); /* Timing not critical for this one */ DELAY(t->t_rsth - (t->t_pdh + t->t_pdl / 2)); /* Timing not critical for this one */
/* /*
* Read the state of the bus after we've waited past the end of the rest * Read the state of the bus after we've waited past the end of the rest
* window. It should return to high. If it is low, then we have some * window. It should return to high. If it is low, then we have some
* problem and should abort the reset. * problem and should abort the reset.
*/ */
GETPIN(sc, &buf); GETPIN(sc, &sample);
if (buf == 0) { if (sample == false) {
*bit = -1; *bit = -1;
RELBUS(sc);
return (EIO); return (EIO);
} }
RELBUS(sc);
return (0); return (0);
} }
static devclass_t owc_gpiobus_devclass; static devclass_t owc_gpiobus_devclass;
static device_method_t owc_gpiobus_methods[] = { static device_method_t owc_gpiobus_methods[] = {
/* Device interface */ /* Device interface */
#ifdef FDT
DEVMETHOD(device_identify, owc_gpiobus_identify),
#endif
DEVMETHOD(device_probe, owc_gpiobus_probe), DEVMETHOD(device_probe, owc_gpiobus_probe),
DEVMETHOD(device_attach, owc_gpiobus_attach), DEVMETHOD(device_attach, owc_gpiobus_attach),
DEVMETHOD(device_detach, owc_gpiobus_detach), DEVMETHOD(device_detach, owc_gpiobus_detach),
DEVMETHOD(owll_write_one, owc_gpiobus_write_one), DEVMETHOD(owll_write_one, owc_gpiobus_write_one),
DEVMETHOD(owll_write_zero, owc_gpiobus_write_zero), DEVMETHOD(owll_write_zero, owc_gpiobus_write_zero),
DEVMETHOD(owll_read_data, owc_gpiobus_read_data), DEVMETHOD(owll_read_data, owc_gpiobus_read_data),
DEVMETHOD(owll_reset_and_presence, owc_gpiobus_reset_and_presence), DEVMETHOD(owll_reset_and_presence, owc_gpiobus_reset_and_presence),
{ 0, 0 } { 0, 0 }
}; };
static driver_t owc_gpiobus_driver = { static driver_t owc_gpiobus_driver = {
"owc", "owc",
owc_gpiobus_methods, owc_gpiobus_methods,
sizeof(struct owc_gpiobus_softc), sizeof(struct owc_gpiobus_softc),
}; };
#ifdef FDT
DRIVER_MODULE(owc_gpiobus, simplebus, owc_gpiobus_driver, owc_gpiobus_devclass, 0, 0);
#endif
DRIVER_MODULE(owc_gpiobus, gpiobus, owc_gpiobus_driver, owc_gpiobus_devclass, 0, 0); DRIVER_MODULE(owc_gpiobus, gpiobus, owc_gpiobus_driver, owc_gpiobus_devclass, 0, 0);
MODULE_DEPEND(owc_gpiobus, ow, 1, 1, 1); MODULE_DEPEND(owc_gpiobus, ow, 1, 1, 1);
MODULE_DEPEND(owc_gpiobus, gpiobus, 1, 1, 1); MODULE_DEPEND(owc_gpiobus, gpiobus, 1, 1, 1);
MODULE_VERSION(owc_gpiobus, 1); MODULE_VERSION(owc_gpiobus, 1);