MFC r274641, r274644, r274822, r276049:

  Allow i2c bus speed to be configured via hints, FDT data, and sysctl.

  Implement bus speed setting for OMAP4, AM335x, and imx5/6.

  Fix the i2c bus speed divisors for TI OMAP4 and AM335x to give the
  advertised 100, 400, and 1000 KHz speeds.

PR:		195009

4 files changed, 86 insertions, 5 deletions

diff --git a/sys/dev/iicbus/iicbus.c b/sys/dev/iicbus/iicbus.c
index d919277..dc56760 100644
--- a/sys/dev/iicbus/iicbus.c
+++ b/sys/dev/iicbus/iicbus.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/module.h>
 #include <sys/mutex.h>
+#include <sys/sysctl.h>
 #include <sys/bus.h> 
 
 #include <dev/iicbus/iiconf.h>
@@ -96,6 +97,7 @@ iicbus_attach(device_t dev)
 
 	sc->dev = dev;
 	mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
+	iicbus_init_frequency(dev, 0);
 	iicbus_reset(dev, IIC_FASTEST, 0, NULL);
 	if (resource_int_value(device_get_name(dev),
 		device_get_unit(dev), "strict", &strict) == 0)
@@ -243,6 +245,51 @@ iicbus_null_repeated_start(device_t dev, u_char addr)
 	return (IIC_ENOTSUPP);
 }
 
+void
+iicbus_init_frequency(device_t dev, u_int bus_freq)
+{
+	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
+
+	/*
+	 * If a bus frequency value was passed in, use it.  Otherwise initialize
+	 * it first to the standard i2c 100KHz frequency, then override that
+	 * from a hint if one exists.
+	 */
+	if (bus_freq > 0)
+		sc->bus_freq = bus_freq;
+	else {
+		sc->bus_freq = 100000;
+		resource_int_value(device_get_name(dev), device_get_unit(dev),
+		    "frequency", (int *)&sc->bus_freq);
+	}
+	/*
+	 * Set up the sysctl that allows the bus frequency to be changed.
+	 * It is flagged as a tunable so that the user can set the value in
+	 * loader(8), and that will override any other setting from any source.
+	 * The sysctl tunable/value is the one most directly controlled by the
+	 * user and thus the one that always takes precedence.
+	 */
+	SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
+	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
+	    OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
+	    sc->bus_freq, "Bus frequency in Hz");
+}
+
+static u_int
+iicbus_get_frequency(device_t dev, u_char speed)
+{
+	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
+
+	/*
+	 * If the frequency has not been configured for the bus, or the request
+	 * is specifically for SLOW speed, use the standard 100KHz rate, else
+	 * use the configured bus speed.
+	 */
+	if (sc->bus_freq == 0 || speed == IIC_SLOW)
+		return (100000);
+	return (sc->bus_freq);
+}
+
 static device_method_t iicbus_methods[] = {
         /* device interface */
         DEVMETHOD(device_probe,         iicbus_probe),
@@ -260,6 +307,7 @@ static device_method_t iicbus_methods[] = {
 
 	/* iicbus interface */
 	DEVMETHOD(iicbus_transfer,	iicbus_transfer),
+	DEVMETHOD(iicbus_get_frequency,	iicbus_get_frequency),
 
 	DEVMETHOD_END
 };
diff --git a/sys/dev/iicbus/iicbus.h b/sys/dev/iicbus/iicbus.h
index 54fe980..b5905ad 100644
--- a/sys/dev/iicbus/iicbus.h
+++ b/sys/dev/iicbus/iicbus.h
@@ -44,6 +44,7 @@ struct iicbus_softc
 	u_char strict;		/* deny operations that violate the
 				 * I2C protocol */
 	struct mtx lock;
+	u_int bus_freq;		/* Configured bus Hz. */
 };
 
 struct iicbus_ivar
@@ -67,7 +68,8 @@ IICBUS_ACCESSOR(nostop,		NOSTOP,		bool)
 #define	IICBUS_UNLOCK(sc)      		mtx_unlock(&(sc)->lock)
 #define	IICBUS_ASSERT_LOCKED(sc)       	mtx_assert(&(sc)->lock, MA_OWNED)
 
-extern int iicbus_generic_intr(device_t dev, int event, char *buf);
+int  iicbus_generic_intr(device_t dev, int event, char *buf);
+void iicbus_init_frequency(device_t dev, u_int bus_freq);
 
 extern driver_t iicbus_driver;
 extern devclass_t iicbus_devclass;
diff --git a/sys/dev/iicbus/iicbus_if.m b/sys/dev/iicbus/iicbus_if.m
index c57fac5..120b5e7 100644
--- a/sys/dev/iicbus/iicbus_if.m
+++ b/sys/dev/iicbus/iicbus_if.m
@@ -31,6 +31,15 @@
 
 INTERFACE iicbus;
 
+CODE {
+	static u_int
+	iicbus_default_frequency(device_t bus, u_char speed)
+	{
+
+		return (100000);
+	}
+};
+
 #
 # Interpret interrupt
 #
@@ -115,3 +124,14 @@ METHOD int transfer {
 	struct iic_msg *msgs;
 	uint32_t nmsgs;
 };
+
+#
+# Return the frequency in Hz for the bus running at the given 
+# symbolic speed.  Only the IIC_SLOW speed has meaning, it is always
+# 100KHz.  The UNKNOWN, FAST, and FASTEST rates all map to the
+# configured bus frequency, or 100KHz when not otherwise configured.
+#
+METHOD u_int get_frequency {
+	device_t dev;
+	u_char speed;
+} DEFAULT iicbus_default_frequency;
diff --git a/sys/dev/ofw/ofw_iicbus.c b/sys/dev/ofw/ofw_iicbus.c
index 1574f6e..f6d1be5 100644
--- a/sys/dev/ofw/ofw_iicbus.c
+++ b/sys/dev/ofw/ofw_iicbus.c
@@ -101,12 +101,24 @@ ofw_iicbus_attach(device_t dev)
 {
 	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
 	struct ofw_iicbus_devinfo *dinfo;
-	phandle_t child;
-	pcell_t paddr;
+	phandle_t child, node;
+	pcell_t freq, paddr;
 	device_t childdev;
 
 	sc->dev = dev;
 	mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
+
+	/*
+	 * If there is a clock-frequency property for the device node, use it as
+	 * the starting value for the bus frequency.  Then call the common
+	 * routine that handles the tunable/sysctl which allows the FDT value to
+	 * be overridden by the user.
+	 */
+	node = ofw_bus_get_node(dev);
+	freq = 0;
+	OF_getencprop(node, "clock-frequency", &freq, sizeof(freq));
+	iicbus_init_frequency(dev, freq);
+	
 	iicbus_reset(dev, IIC_FASTEST, 0, NULL);
 
 	bus_generic_probe(dev);
@@ -115,8 +127,7 @@ ofw_iicbus_attach(device_t dev)
 	/*
 	 * Attach those children represented in the device tree.
 	 */
-	for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
-	    child = OF_peer(child)) {
+	for (child = OF_child(node); child != 0; child = OF_peer(child)) {
 		/*
 		 * Try to get the I2C address first from the i2c-address
 		 * property, then try the reg property.  It moves around