ec/google/chromeec: Add EC Mux device

Introduce an EC Mux ACPI device, which will control retimer and discrete
(off-AP) mux configuration.

BUG=b:208883648
TEST=None
BRANCH=None

Change-Id: Ia2022810292783583ee5f09ce29a63b96686dbb8
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63792
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/ec/google/chromeec/Makefile.inc

@@ -2,6 +2,7 @@ ifeq ($(CONFIG_EC_GOOGLE_CHROMEEC),y)
 
 subdirs-y += audio_codec
 subdirs-y += i2c_tunnel
+subdirs-y += mux
 
 bootblock-$(CONFIG_EC_GOOGLE_CHROMEEC_BOARDID) += ec_boardid.c
 verstage-$(CONFIG_EC_GOOGLE_CHROMEEC_BOARDID) += ec_boardid.c

src/ec/google/chromeec/mux/Kconfig

@@ -0,0 +1,11 @@
+if EC_GOOGLE_CHROMEEC
+
+config EC_GOOGLE_CHROMEEC_MUX
+	bool
+	depends on HAVE_ACPI_TABLES
+	help
+	  This enables the Cros EC Mux driver that is required to fill the
+	  SSDT nodes for the EC Mux platform device which is used to
+	  configure Type C muxes and retimers.
+
+endif

src/ec/google/chromeec/mux/Makefile.inc

@@ -0,0 +1,2 @@
+subdirs-y += conn
+ramstage-$(CONFIG_EC_GOOGLE_CHROMEEC_MUX) += mux.c

src/ec/google/chromeec/mux/conn/Makefile.inc

@@ -0,0 +1 @@
+ramstage-$(CONFIG_EC_GOOGLE_CHROMEEC_MUX) += conn.c

src/ec/google/chromeec/mux/conn/conn.c

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpigen.h>
+
+static const char *conn_acpi_name(const struct device *dev)
+{
+	static char name[5];
+	snprintf(name, sizeof(name), "CON%1X", dev->path.generic.id);
+	return name;
+}
+
+static void conn_fill_ssdt(const struct device *dev)
+{
+	const char *name;
+	name = acpi_device_name(dev);
+	if (!name)
+		return;
+
+	acpigen_write_scope(acpi_device_scope(dev));
+	acpigen_write_device(name);
+
+	acpigen_write_name_integer("_ADR", dev->path.generic.id);
+
+	acpigen_write_device_end();
+	acpigen_write_scope_end();
+}
+
+static struct device_operations conn_dev_ops = {
+	.read_resources	= noop_read_resources,
+	.set_resources	= noop_set_resources,
+	.acpi_name	= conn_acpi_name,
+	.acpi_fill_ssdt	= conn_fill_ssdt,
+};
+
+static void conn_enable(struct device *dev)
+{
+	dev->ops = &conn_dev_ops;
+}
+
+struct chip_operations ec_google_chromeec_mux_conn_ops = {
+	CHIP_NAME("CrosEC Type C Mux device")
+	.enable_dev	= conn_enable,
+};

src/ec/google/chromeec/mux/mux.c

@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpigen.h>
+
+#define GOOGLE_CHROMEEC_MUX_DEVICE_HID		"GOOG001A"
+#define GOOGLE_CHROMEEC_MUX_DEVICE_NAME		"ECMX"
+
+static void mux_fill_ssdt(const struct device *dev)
+{
+	acpigen_write_scope(acpi_device_scope(dev));
+	acpigen_write_device(GOOGLE_CHROMEEC_MUX_DEVICE_NAME);
+	acpigen_write_name_string("_HID", GOOGLE_CHROMEEC_MUX_DEVICE_HID);
+	acpigen_write_name_string("_DDN", "ChromeOS EC Embedded Controller "
+				  "Mux & Retimer control");
+
+	acpigen_write_device_end();
+	acpigen_write_scope_end();
+}
+
+static const char *mux_acpi_name(const struct device *dev)
+{
+	return GOOGLE_CHROMEEC_MUX_DEVICE_NAME;
+}
+
+static struct device_operations mux_ops = {
+	.read_resources		= noop_read_resources,
+	.set_resources		= noop_set_resources,
+	.acpi_name		= mux_acpi_name,
+	.acpi_fill_ssdt		= mux_fill_ssdt,
+	.scan_bus		= scan_static_bus,
+};
+
+static void mux_enable(struct device *dev)
+{
+	dev->ops = &mux_ops;
+}
+
+struct chip_operations ec_google_chromeec_mux_ops = {
+	CHIP_NAME("CrosEC Type C Mux device")
+	.enable_dev = mux_enable
+};