ig4(4): Add an EMAG device type

Sponsored by: Ampere Computing LLC, Netflix
Submitted by: allanjude
Differential Revision: https://reviews.freebsd.org/D28746
Reviewed by: imp

sys/dev/ichiic/ig4_acpi.c

@@ -83,13 +83,21 @@ static int
 ig4iic_acpi_attach(device_t dev)
 {
 	ig4iic_softc_t	*sc;
+	char *str;
 	int error;
 
 	sc = device_get_softc(dev);
 
 	sc->dev = dev;
-	/* All the HIDs matched are Atom SOCs. */
-	sc->version = IG4_ATOM;
+	error = ACPI_ID_PROBE(device_get_parent(dev), dev, ig4iic_ids, &str);
+	if (error > 0)
+		return (error);
+	if (strcmp(str, "APMC0D0F") == 0) {
+		sc->version = IG4_EMAG;
+	} else {
+		/* All the other HIDs matched are Atom SOCs. */
+		sc->version = IG4_ATOM;
+	}
 	sc->regs_rid = 0;
 	sc->regs_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
 					  &sc->regs_rid, RF_ACTIVE);

sys/dev/ichiic/ig4_iic.c

@@ -89,6 +89,9 @@
  * Ig4 hardware parameters except Haswell are taken from intel_lpss driver
  */
 static const struct ig4_hw ig4iic_hw[] = {
+	[IG4_EMAG] = {
+		.ic_clock_rate = 100,	/* MHz */
+	},
 	[IG4_HASWELL] = {
 		.ic_clock_rate = 100,	/* MHz */
 		.sda_hold_time = 90,	/* nsec */

sys/dev/ichiic/ig4_var.h

@@ -42,6 +42,7 @@
 #include "iicbus_if.h"
 
 enum ig4_vers {
+	IG4_EMAG,
 	IG4_HASWELL,
 	IG4_ATOM,
 	IG4_SKYLAKE,