devi2c: add generic i2c bus driver

1 files changed, 597 insertions, 0 deletions

diff --git a/sys/src/9/port/devi2c.c b/sys/src/9/port/devi2c.c
new file mode 100644
index 000000000..568480ae7
--- /dev/null
+++ b/sys/src/9/port/devi2c.c
@@ -0,0 +1,597 @@
+/* I²C bus driver */
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "../port/error.h"
+#include "../port/i2c.h"
+
+enum {
+	Qdir = 0,	/* #J */
+	Qbus,		/* #J/bus */
+	Qctl,		/* #J/bus/i2c.n.ctl */
+	Qdata,		/* #J/bus/i2c.n.data */
+};
+
+#define TYPE(q)		((ulong)(q).path & 0x0F)
+#define BUS(q)		(((ulong)(q).path>>4) & 0xFF)
+#define DEV(q)		(((ulong)(q).path>>12) & 0xFFF)
+#define QID(d, b, t)	(((d)<<12)|((b)<<4)|(t))
+
+static I2Cbus *buses[16];
+
+static I2Cdev *devs[1024];
+static Lock devslock;
+
+static void probebus(I2Cbus *bus);
+
+void
+addi2cbus(I2Cbus *bus)
+{
+	int i;
+
+	if(bus == nil)
+		return;
+
+	for(i = 0; i < nelem(buses); i++){
+		if(buses[i] == nil
+		|| buses[i] == bus
+		|| strcmp(bus->name, buses[i]->name) == 0){
+			buses[i] = bus;
+			break;
+		}
+	}
+}
+
+I2Cbus*
+i2cbus(char *name)
+{
+	I2Cbus *bus;
+	int i;
+
+	for(i = 0; i < nelem(buses); i++){
+		bus = buses[i];
+		if(bus == nil)
+			break;
+		if(strcmp(bus->name, name) == 0){
+			probebus(bus);
+			return bus;
+		}
+	}
+	return nil;
+}
+
+void
+addi2cdev(I2Cdev *dev)
+{
+	int i;
+
+	if(dev == nil || dev->bus == nil)
+		return;
+
+	lock(&devslock);
+	for(i = 0; i < nelem(devs); i++){
+		if(devs[i] == nil
+		|| devs[i] == dev
+		|| devs[i]->addr == dev->addr && devs[i]->bus == dev->bus){
+			devs[i] = dev;
+			unlock(&devslock);
+			return;
+		}
+	}
+	unlock(&devslock);
+}
+
+I2Cdev*
+i2cdev(I2Cbus *bus, int addr)
+{
+	I2Cdev *dev;
+	int i;
+
+	if(bus == nil || addr < 0 || addr >= 1<<10)
+		return nil;
+
+	lock(&devslock);
+	for(i = 0; i < nelem(devs) && (dev = devs[i]) != nil; i++){
+		if(dev->addr == addr && dev->bus == bus){
+			unlock(&devslock);
+			return dev;
+		}
+	}
+	unlock(&devslock);
+
+	return nil;
+}
+
+
+static int
+enterbus(I2Cbus *bus)
+{
+	if(up != nil && islo()){
+		eqlock(bus);
+		return 1;
+	} else {
+		while(!canqlock(bus))
+			;
+		return 0;
+	}
+}
+
+static void
+leavebus(I2Cbus *bus)
+{
+	qunlock(bus);
+}
+
+int
+i2cbusio(I2Cbus *bus, uchar *pkt, int olen, int ilen)
+{
+	int user, n;
+
+	user =  enterbus(bus);
+	if(!bus->probed){
+		leavebus(bus);
+		return -1;
+	}
+	if(user && waserror()){
+		(*bus->io)(bus, nil, 0, 0);
+		leavebus(bus);
+		nexterror();
+	}
+// iprint("%s: <- %.*H\n", bus->name, olen, pkt);
+	n = (*bus->io)(bus, pkt, olen, ilen);
+// if(n > olen) iprint("%s: -> %.*H\n", bus->name, n - olen, pkt+olen);
+
+	leavebus(bus);
+	if(user) poperror();
+
+	return n;
+}
+
+static int
+putaddr(I2Cdev *dev, int isread, uchar *pkt, vlong addr)
+{
+	int n, o = 0;
+
+	if(dev->a10){
+		pkt[o++] = 0xF0 | (dev->addr>>(8-1))&6 | (isread != 0);
+		pkt[o++] = dev->addr;
+	} else
+		pkt[o++] = dev->addr<<1 | (isread != 0);
+
+	if(addr >= 0){
+		for(n=0; n<dev->subaddr; n++)
+			pkt[o++] = addr >> (n*8);
+	}
+
+	return o;
+}
+
+int
+i2csend(I2Cdev *dev, void *data, int len, vlong addr)
+{
+	uchar pkt[138];
+	int o;
+
+	o = putaddr(dev, 0, pkt, addr);
+	if(o+len > sizeof(pkt))
+		len = sizeof(pkt)-o;
+
+	if(len > 0)
+		memmove(pkt+o, data, len);
+
+	return i2cbusio(dev->bus, pkt, o + len, 0) - o;
+}
+	
+int
+i2crecv(I2Cdev *dev, void *data, int len, vlong addr)
+{
+	uchar pkt[138];
+	int o;
+
+	o = putaddr(dev, 1, pkt, addr);
+	if(o+len > sizeof(pkt))
+		len = sizeof(pkt)-o;
+
+	len = i2cbusio(dev->bus, pkt, o, len) - o;
+	if(len > 0)
+		memmove(data, pkt+o, len);
+
+	return  len;
+}
+
+int
+i2cquick(I2Cdev *dev, int rw)
+{
+	uchar pkt[2];
+	int o = putaddr(dev, rw, pkt, -1);
+	if(i2cbusio(dev->bus, pkt, o, 0) != o)
+		return -1;
+	return rw != 0;
+}
+int
+i2crecvbyte(I2Cdev *dev)
+{
+	uchar pkt[2+1];
+	int o = putaddr(dev, 1, pkt, -1);
+	if(i2cbusio(dev->bus, pkt, o, 1) - o != 1)
+		return -1;
+	return pkt[o];
+}
+int
+i2csendbyte(I2Cdev *dev, uchar b)
+{
+	uchar pkt[2+1];
+	int o = putaddr(dev, 0, pkt, -1);
+	pkt[o] = b;
+	if(i2cbusio(dev->bus, pkt, o+1, 0) - o != 1)
+		return -1;
+	return b;
+}
+int
+i2creadbyte(I2Cdev *dev, ulong addr)
+{
+	uchar pkt[2+4+1];
+	int o = putaddr(dev, 1, pkt, addr);
+	if(i2cbusio(dev->bus, pkt, o, 1) - o != 1)
+		return -1;
+	return pkt[o];
+}
+int
+i2cwritebyte(I2Cdev *dev, ulong addr, uchar b)
+{
+	uchar pkt[2+4+1];
+	int o = putaddr(dev, 0, pkt, addr);
+	pkt[o] = b;
+	if(i2cbusio(dev->bus, pkt, o+1, 0) - o != 1)
+		return -1;
+	return b;
+}
+int
+i2creadword(I2Cdev *dev, ulong addr)
+{
+	uchar pkt[2+4+2];
+	int o = putaddr(dev, 1, pkt, addr);
+	if(i2cbusio(dev->bus, pkt, o, 2) - o != 2)
+		return -1;
+	return pkt[o] | (ushort)pkt[o+1]<<8;
+}
+int
+i2cwriteword(I2Cdev *dev, ulong addr, ushort w)
+{
+	uchar pkt[2+4+2];
+	int o = putaddr(dev, 0, pkt, addr);
+	pkt[o+0] = w;
+	pkt[o+1] = w>>8;
+	if(i2cbusio(dev->bus, pkt, o+2, 0) - o != 2)
+		return -1;
+	return w;
+}
+vlong
+i2cread32(I2Cdev *dev, ulong addr)
+{
+	uchar pkt[2+4+4];
+	int o = putaddr(dev, 1, pkt, addr);
+	if(i2cbusio(dev->bus, pkt, o, 4) - o != 4)
+		return -1;
+	return pkt[o] | (ulong)pkt[o+1]<<8 | (ulong)pkt[o+2]<<16 | (ulong)pkt[o+3]<<24;
+}
+vlong
+i2cwrite32(I2Cdev *dev, ulong addr, ulong u)
+{
+	uchar pkt[2+4+4];
+	int o = putaddr(dev, 0, pkt, addr);
+	pkt[o+0] = u;
+	pkt[o+1] = u>>8;
+	pkt[o+2] = u>>16;
+	pkt[o+3] = u>>24;
+	if(i2cbusio(dev->bus, pkt, o+4, 0) - o != 4)
+		return -1;
+	return u;
+}
+
+static void
+probeddev(I2Cdev *dummy)
+{
+	I2Cdev *dev = smalloc(sizeof(I2Cdev));
+	memmove(dev, dummy, sizeof(I2Cdev));
+	addi2cdev(dev);
+}
+
+static void
+probebus(I2Cbus *bus)
+{
+	I2Cdev dummy;
+	uchar pkt[2];
+	int user, n;
+
+	if(bus->probed)
+		return;
+
+	user = enterbus(bus);
+	if(bus->probed){
+		leavebus(bus);
+		return;
+	}
+	if(user && waserror()
+	|| (*bus->init)(bus)){
+		leavebus(bus);
+		if(user) nexterror();
+		return;
+	}
+
+	memset(&dummy, 0, sizeof(dummy));
+	dummy.bus = bus;
+
+	dummy.a10 = 0;
+	for(dummy.addr = 8; dummy.addr < 0x78; dummy.addr++) {
+		if(i2cdev(bus, dummy.addr) != nil)
+			continue;
+		if(user && waserror()){
+			(*bus->io)(bus, nil, 0, 0);
+			continue;
+		}
+		n = putaddr(&dummy, 0, pkt, -1);
+		if((*bus->io)(bus, pkt, n, 0) == n)
+			probeddev(&dummy);
+		if(user) poperror();
+	}
+
+	dummy.a10 = 1;
+	for(dummy.addr = 0; dummy.addr < (1<<10); dummy.addr++) {
+		if(i2cdev(bus, dummy.addr) != nil)
+			continue;
+		if(user && waserror()){
+			(*bus->io)(bus, nil, 0, 0);
+			continue;
+		}
+		n = putaddr(&dummy, 0, pkt, -1);
+		if((*bus->io)(bus, pkt, n, 0) == n)
+			probeddev(&dummy);
+		if(user) poperror();
+	}
+
+	bus->probed = 1;
+	leavebus(bus);
+	if(user) poperror();
+}
+
+static int
+i2cgen(Chan *c, char *, Dirtab*, int, int s, Dir *dp)
+{
+	I2Cbus *bus;
+	I2Cdev *dev;
+
+	Qid q;
+
+	switch(TYPE(c->qid)){
+	case Qdir:
+		if(s == DEVDOTDOT){
+		Gendir:
+			mkqid(&q, QID(0, 0, Qdir), 0, QTDIR);
+			snprint(up->genbuf, sizeof up->genbuf, "#J");
+			devdir(c, q, up->genbuf, 0, eve, 0500, dp);
+			return 1;
+		}
+		if(s >= nelem(buses))
+			return -1;
+		bus = buses[s];
+		if(bus == nil)
+			return -1;
+		mkqid(&q, QID(0, s, Qbus), 0, QTDIR);
+		devdir(c, q, bus->name, 0, eve, 0500, dp);
+		return 1;
+	case Qbus:
+		if(s == DEVDOTDOT)
+			goto Gendir;
+		if((s/2) >= nelem(devs))
+			return -1;
+
+		bus = buses[BUS(c->qid)];
+		probebus(bus);
+
+		lock(&devslock);
+		dev = devs[s/2];
+		unlock(&devslock);
+
+		if(dev == nil)
+			return -1;
+		if(dev->bus != bus)
+			return 0;
+		if(s & 1){
+			mkqid(&q, QID(dev->addr, BUS(c->qid), Qdata), 0, 0);
+			goto Gendata;
+		}
+		mkqid(&q, QID(dev->addr, BUS(c->qid), Qctl), 0, 0);
+		goto Genctl;
+	case Qctl:
+		q = c->qid;
+	Genctl:
+		snprint(up->genbuf, sizeof up->genbuf, "i2c.%lux.ctl", DEV(q));
+		devdir(c, q, up->genbuf, 0, eve, 0600, dp);
+		return 1;
+	case Qdata:
+		q = c->qid;
+		bus = buses[BUS(q)];
+		dev = i2cdev(bus, DEV(q));
+		if(dev == nil)
+			return -1;
+	Gendata:
+		snprint(up->genbuf, sizeof up->genbuf, "i2c.%lux.data", DEV(q));
+		devdir(c, q, up->genbuf, dev->size, eve, 0600, dp);
+		return 1;
+	}
+	return -1;
+}
+
+static Chan*
+i2cattach(char *spec)
+{
+	return devattach('J', spec);
+}
+
+static Chan*
+i2copen(Chan *c, int mode)
+{
+	c = devopen(c, mode, nil, 0, i2cgen);
+	switch(TYPE(c->qid)){
+	case Qctl:
+	case Qdata:
+		c->aux = i2cdev(buses[BUS(c->qid)], DEV(c->qid));
+		if(c->aux == nil)
+			error(Enonexist);
+		break;
+	}
+	return c;
+}
+
+enum {
+	CMsize,
+	CMsubaddress,
+};
+
+static Cmdtab i2cctlmsg[] =
+{
+	CMsize,		"size",		2,
+	CMsubaddress,	"subaddress",	2,
+};
+
+static long
+i2cwrctl(I2Cdev *dev, void *data, long len)
+{
+	Cmdbuf *cb;
+	Cmdtab *ct;
+	ulong u;
+
+	cb = parsecmd(data, len);
+	if(waserror()){
+		free(cb);
+		nexterror();
+	}
+	ct = lookupcmd(cb, i2cctlmsg, nelem(i2cctlmsg));
+	switch(ct->index){
+	case CMsize:
+		dev->size = strtoul(cb->f[1], nil, 0);
+		break;
+	case CMsubaddress:
+		u = strtoul(cb->f[1], nil, 0);
+		if(u > 4)
+			cmderror(cb, Ebadarg);
+		dev->subaddr = u;
+		break;
+	default:
+		cmderror(cb, Ebadarg);
+	}
+	free(cb);
+	poperror();
+	return len;
+}
+
+static long
+i2crdctl(I2Cdev *dev, void *data, long len, vlong offset)
+{
+	char cfg[64];
+
+	snprint(cfg, sizeof(cfg), "size %lud\nsubaddress %d\n", dev->size, dev->subaddr);
+	return readstr((ulong)offset, data, len, cfg);
+}
+
+static long
+i2cwrite(Chan *c, void *data, long len, vlong offset)
+{
+	I2Cdev *dev;
+
+	switch(TYPE(c->qid)){
+	default:
+		error(Egreg);
+		return -1;
+	case Qctl:
+		dev = c->aux;
+		return i2cwrctl(dev, data, len);
+	case Qdata:
+		break;
+	}
+	dev = c->aux;
+	if(dev->size){
+		if(offset+len > dev->size){
+			if(offset >= dev->size)
+				return 0;
+			len = dev->size - offset;
+		}
+	}
+	len = i2csend(dev, data, len, offset);
+	if(len < 0)
+		error(Eio);
+	return len;
+}
+
+static long
+i2cread(Chan *c, void *data, long len, vlong offset)
+{
+	I2Cdev *dev;
+
+	if(c->qid.type == QTDIR)
+		return devdirread(c, data, len, nil, 0, i2cgen);
+
+	switch(TYPE(c->qid)){
+	default:
+		error(Egreg);
+	case Qctl:
+		dev = c->aux;
+		return i2crdctl(dev, data, len, offset);
+	case Qdata:
+		break;
+	}
+	dev = c->aux;
+	if(dev->size){
+		if(offset+len > dev->size){
+			if(offset >= dev->size)
+				return 0;
+			len = dev->size - offset;
+		}
+	}
+	len = i2crecv(dev, data, len, offset);
+	if(len < 0)
+		error(Eio);
+	return len;
+}
+
+void
+i2cclose(Chan*)
+{
+}
+
+static Walkqid*
+i2cwalk(Chan *c, Chan *nc, char **name, int nname)
+{
+	return devwalk(c, nc, name, nname, nil, 0, i2cgen);
+}
+
+static int
+i2cstat(Chan *c, uchar *dp, int n)
+{
+	return devstat(c, dp, n, nil, 0, i2cgen);
+}
+
+Dev i2cdevtab = {
+	'J',
+	"i2c",
+
+	devreset,
+	devinit,
+	devshutdown,
+	i2cattach,
+	i2cwalk,
+	i2cstat,
+	i2copen,
+	devcreate,
+	i2cclose,
+	i2cread,
+	devbread,
+	i2cwrite,
+	devbwrite,
+	devremove,
+	devwstat,
+	devpower,
+};