add iic interface to ig4 driver, move isl and cyapa to iicbus

Summary:
The hardware does not expose a classic SMBus interface.
Instead it has a lower level interface that can express a far richer
I2C protocol than what smbus offers.  However, the interface does not
provide a way to explicitly generate the I2C stop and start conditions.
It's only possible to request that the stop condition is generated
after transferring the next byte in either direction.  So, at least
one data byte must always be transferred.
Thus, some I2C sequences are impossible to generate, e.g., an equivalent
of smbus quick command (<start>-<slave addr>-<r/w bit>-<stop>).

At the same time isl(4) and cyapa(4) are moved to iicbus and now they use
iicbus_transfer for communication.  Previously they used smbus_trans()
interface that is not defined by the SMBus protocol and was implemented
only by ig4(4).  In fact, that interface was impossible to implement
for the typical SMBus controllers like intpm(4) or ichsmb(4) where
a type of the SMBus command must be programmed.

The plan is to remove smbus_trans() and all its uses.
As an aside, the smbus_trans() method deviates from the standard,
but perhaps backwards, FreeBSD convention of using 8-bit slave
addresses (shifted by 1 bit to the left).  The method expects
7-bit addresses.

There is a user facing consequence of this change.
A user must now provide device hints for isl and cyapa that specify an iicbus to use
and a slave address on it.
On Chromebook hardware where isl and cyapa devices are commonly found
it is also possible to use a new chromebook_platform(4) driver that
automatically configures isl and cyapa devices.  There is no need to
provide the device hints in that case,

Right now smbus(4) driver tries to discover all slaves on the bus.
That is very dangerous.  Fortunately, the probing code uses smbus_trans()
to do its job, so it is really enabled for ig4 only.
The plan is to remove that auto-probing code and smbus_trans().

Tested by:	grembo, Matthias Apitz <guru@unixarea.de> (w/o
		chromebook_platform)
Discussed with:	grembo, imp
Reviewed by:	wblock (docs)
MFC after:	1 month
Relnotes:	yes
Differential Revision: https://reviews.freebsd.org/D8172

1 files changed, 59 insertions, 51 deletions

diff --git a/sys/dev/cyapa/cyapa.c b/sys/dev/cyapa/cyapa.c
index 035121d7468b..d3a0ef18d83e 100644
--- a/sys/dev/cyapa/cyapa.c
+++ b/sys/dev/cyapa/cyapa.c
@@ -122,11 +122,11 @@ __FBSDID("$FreeBSD$");
 #include <sys/uio.h>
 #include <sys/vnode.h>
 
-#include <dev/smbus/smbconf.h>
-#include <dev/smbus/smbus.h>
+#include <dev/iicbus/iiconf.h>
+#include <dev/iicbus/iicbus.h>
 #include <dev/cyapa/cyapa.h>
 
-#include "smbus_if.h"
+#include "iicbus_if.h"
 #include "bus_if.h"
 #include "device_if.h"
 
@@ -149,7 +149,6 @@ struct cyapa_fifo {
 struct cyapa_softc {
 	device_t dev;
 	int	count;			/* >0 if device opened */
-	int	addr;
 	struct cdev *devnode;
 	struct selinfo selinfo;
 	struct mtx mutex;
@@ -273,6 +272,30 @@ static int cyapa_reset = 0;
 SYSCTL_INT(_debug, OID_AUTO, cyapa_reset, CTLFLAG_RW,
 	    &cyapa_reset, 0, "Reset track pad");
 
+static int
+cyapa_read_bytes(device_t dev, uint8_t reg, uint8_t *val, int cnt)
+{
+	uint16_t addr = iicbus_get_addr(dev);
+	struct iic_msg msgs[] = {
+	     { addr, IIC_M_WR | IIC_M_NOSTOP, 1, &reg },
+	     { addr, IIC_M_RD, cnt, val },
+	};
+
+	return (iicbus_transfer(dev, msgs, nitems(msgs)));
+}
+
+static int
+cyapa_write_bytes(device_t dev, uint8_t reg, const uint8_t *val, int cnt)
+{
+	uint16_t addr = iicbus_get_addr(dev);
+	struct iic_msg msgs[] = {
+	     { addr, IIC_M_WR | IIC_M_NOSTOP, 1, &reg },
+	     { addr, IIC_M_WR | IIC_M_NOSTART, cnt, __DECONST(uint8_t *, val) },
+	};
+
+	return (iicbus_transfer(dev, msgs, nitems(msgs)));
+}
+
 static void
 cyapa_lock(struct cyapa_softc *sc)
 {
@@ -318,7 +341,7 @@ cyapa_notify(struct cyapa_softc *sc)
  * Initialize the device
  */
 static int
-init_device(device_t dev, struct cyapa_cap *cap, int addr, int probe)
+init_device(device_t dev, struct cyapa_cap *cap, int probe)
 {
 	static char bl_exit[] = {
 		0x00, 0xff, 0xa5, 0x00, 0x01,
@@ -326,17 +349,13 @@ init_device(device_t dev, struct cyapa_cap *cap, int addr, int probe)
 	static char bl_deactivate[] = {
 		0x00, 0xff, 0x3b, 0x00, 0x01,
 		0x02, 0x03, 0x04, 0x05, 0x06, 0x07 };
-	device_t bus;
 	struct cyapa_boot_regs boot;
 	int error;
 	int retries;
 
-	bus = device_get_parent(dev);	/* smbus */
-
 	/* Get status */
-	error = smbus_trans(bus, addr, CMD_BOOT_STATUS,
-	    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-	    NULL, 0, (void *)&boot, sizeof(boot), NULL);
+	error = cyapa_read_bytes(dev, CMD_BOOT_STATUS,
+	    (void *)&boot, sizeof(boot));
 	if (error)
 		goto done;
 
@@ -350,25 +369,21 @@ init_device(device_t dev, struct cyapa_cap *cap, int addr, int probe)
 			/* Busy, wait loop. */
 		} else if (boot.error & CYAPA_ERROR_BOOTLOADER) {
 			/* Magic */
-			error = smbus_trans(bus, addr, CMD_BOOT_STATUS,
-			    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-			    bl_deactivate, sizeof(bl_deactivate),
-			    NULL, 0, NULL);
+			error = cyapa_write_bytes(dev, CMD_BOOT_STATUS,
+			    bl_deactivate, sizeof(bl_deactivate));
 			if (error)
 				goto done;
 		} else {
 			/* Magic */
-			error = smbus_trans(bus, addr, CMD_BOOT_STATUS,
-			    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-			    bl_exit, sizeof(bl_exit), NULL, 0, NULL);
+			error = cyapa_write_bytes(dev, CMD_BOOT_STATUS,
+			    bl_exit, sizeof(bl_exit));
 			if (error)
 				goto done;
 		}
 		pause("cyapab1", (hz * 2) / 10);
 		--retries;
-		error = smbus_trans(bus, addr, CMD_BOOT_STATUS,
-		    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-		    NULL, 0, (void *)&boot, sizeof(boot), NULL);
+		error = cyapa_read_bytes(dev, CMD_BOOT_STATUS,
+		    (void *)&boot, sizeof(boot));
 		if (error)
 			goto done;
 	}
@@ -381,9 +396,8 @@ init_device(device_t dev, struct cyapa_cap *cap, int addr, int probe)
 
 	/* Check identity */
 	if (cap) {
-		error = smbus_trans(bus, addr, CMD_QUERY_CAPABILITIES,
-		    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-		    NULL, 0, (void *)cap, sizeof(*cap), NULL);
+		error = cyapa_read_bytes(dev, CMD_QUERY_CAPABILITIES,
+		    (void *)cap, sizeof(*cap));
 
 		if (strncmp(cap->prod_ida, "CYTRA", 5) != 0) {
 			device_printf(dev, "Product ID \"%5.5s\" mismatch\n",
@@ -391,9 +405,8 @@ init_device(device_t dev, struct cyapa_cap *cap, int addr, int probe)
 			error = ENXIO;
 		}
 	}
-	error = smbus_trans(bus, addr, CMD_BOOT_STATUS,
-	    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-	    NULL, 0, (void *)&boot, sizeof(boot), NULL);
+	error = cyapa_read_bytes(dev, CMD_BOOT_STATUS,
+	    (void *)&boot, sizeof(boot));
 
 	if (probe == 0)		/* official init */
 		device_printf(dev, "cyapa init status %02x\n", boot.stat);
@@ -452,16 +465,16 @@ cyapa_probe(device_t dev)
 	int addr;
 	int error;
 
-	addr = smbus_get_addr(dev);
+	addr = iicbus_get_addr(dev);
 
 	/*
 	 * 0x67 - cypress trackpad on the acer c720
 	 * (other devices might use other ids).
 	 */
-	if (addr != 0x67)
+	if (addr != 0xce)
 		return (ENXIO);
 
-	error = init_device(dev, &cap, addr, 1);
+	error = init_device(dev, &cap, 1);
 	if (error != 0)
 		return (ENXIO);
 
@@ -482,15 +495,14 @@ cyapa_attach(device_t dev)
 	sc->reporting_mode = 1;
 
 	unit = device_get_unit(dev);
-	addr = smbus_get_addr(dev);
+	addr = iicbus_get_addr(dev);
 
-	if (init_device(dev, &cap, addr, 0))
+	if (init_device(dev, &cap, 0))
 		return (ENXIO);
 
 	mtx_init(&sc->mutex, "cyapa", NULL, MTX_DEF);
 
 	sc->dev = dev;
-	sc->addr = addr;
 
 	knlist_init_mtx(&sc->selinfo.si_note, &sc->mutex);
 
@@ -1159,7 +1171,7 @@ cyapa_poll_thread(void *arg)
 {
 	struct cyapa_softc *sc;
 	struct cyapa_regs regs;
-	device_t bus;		/* smbus */
+	device_t bus;		/* iicbus */
 	int error;
 	int freq;
 	int isidle;
@@ -1180,12 +1192,10 @@ cyapa_poll_thread(void *arg)
 
 	while (!sc->detaching) {
 		cyapa_unlock(sc);
-		error = smbus_request_bus(bus, sc->dev, SMB_WAIT);
+		error = iicbus_request_bus(bus, sc->dev, IIC_WAIT);
 		if (error == 0) {
-			error = smbus_trans(bus, sc->addr, CMD_DEV_STATUS,
-			    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-			    NULL, 0,
-			    (void *)&regs, sizeof(regs), NULL);
+			error = cyapa_read_bytes(sc->dev, CMD_DEV_STATUS,
+			    (void *)&regs, sizeof(regs));
 			if (error == 0) {
 				isidle = cyapa_raw_input(sc, &regs, freq);
 			}
@@ -1200,9 +1210,9 @@ cyapa_poll_thread(void *arg)
 			     (unsigned)(ticks - last_reset) > TIME_TO_RESET)) {
 				cyapa_reset = 0;
 				last_reset = ticks;
-				init_device(sc->dev, NULL, sc->addr, 2);
+				init_device(sc->dev, NULL, 2);
 			}
-			smbus_release_bus(bus, sc->dev);
+			iicbus_release_bus(bus, sc->dev);
 		}
 		pause("cyapw", hz / freq);
 		++sc->poll_ticks;
@@ -1531,18 +1541,16 @@ cyapa_set_power_mode(struct cyapa_softc *sc, int mode)
 	int error;
 
 	bus = device_get_parent(sc->dev);
-	error = smbus_request_bus(bus, sc->dev, SMB_WAIT);
+	error = iicbus_request_bus(bus, sc->dev, IIC_WAIT);
 	if (error == 0) {
-		error = smbus_trans(bus, sc->addr, CMD_POWER_MODE,
-		    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-		    NULL, 0, (void *)&data, 1, NULL);
+		error = cyapa_read_bytes(sc->dev, CMD_POWER_MODE,
+		    &data, 1);
 		data = (data & ~0xFC) | mode;
 		if (error == 0) {
-			error = smbus_trans(bus, sc->addr, CMD_POWER_MODE,
-			    SMB_TRANS_NOCNT | SMB_TRANS_7BIT,
-			    (void *)&data, 1, NULL, 0, NULL);
+			error = cyapa_write_bytes(sc->dev, CMD_POWER_MODE,
+			    &data, 1);
 		}
-		smbus_release_bus(bus, sc->dev);
+		iicbus_release_bus(bus, sc->dev);
 	}
 }
 
@@ -1697,6 +1705,6 @@ cyapa_fuzz(int delta, int *fuzzp)
 	return (delta);
 }
 
-DRIVER_MODULE(cyapa, smbus, cyapa_driver, cyapa_devclass, NULL, NULL);
-MODULE_DEPEND(cyapa, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
+DRIVER_MODULE(cyapa, iicbus, cyapa_driver, cyapa_devclass, NULL, NULL);
+MODULE_DEPEND(cyapa, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
 MODULE_VERSION(cyapa, 1);