[PATCH v3 12/14] staging: typec: Add Generic TCPC mux driver using the mux subsys

[Hans de Goede]

So far the mux functionality of the tcpm code has not been hooked up
in any tcpc drivers. This commit adds a generic TCPC mux driver using
the mux subsys, which tcpc drivers can use to provide mux functionality
in cases where an external my is used.

Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v3:
-Use new devm_mux_control_get_optional()
-Simplify tcpc_gen_mux_set as we now no longer need to worry about the muxes
 being present
-Adjust for updated MUX_TYPEC_* defines
---
 drivers/usb/typec/Makefile       |   2 +-
 drivers/usb/typec/tcpc_gen_mux.c | 122 +++++++++++++++++++++++++++++++++++++++
 include/linux/usb/tcpm.h         |   2 +
 3 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/typec/tcpc_gen_mux.c

diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
index b77688ce1f16..95a7d9c4527b 100644
--- a/drivers/usb/typec/Makefile
+++ b/drivers/usb/typec/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_TYPEC)		+= typec.o
-obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o
+obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o tcpc_gen_mux.o
 obj-y				+= fusb302/
 obj-$(CONFIG_TYPEC_WCOVE)	+= typec_wcove.o
 obj-$(CONFIG_TYPEC_UCSI)	+= ucsi/
diff --git a/drivers/usb/typec/tcpc_gen_mux.c b/drivers/usb/typec/tcpc_gen_mux.c
new file mode 100644
index 000000000000..ea40b52ef6a6
--- /dev/null
+++ b/drivers/usb/typec/tcpc_gen_mux.c
@@ -0,0 +1,122 @@
+/*
+ * Generic TCPC mux driver using the mux subsys
+ *
+ * Copyright (c) 2017 Hans de Goede <hdegoede@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation, or (at your option)
+ * any later version.
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mux/consumer.h>
+#include <linux/mux/usb.h>
+#include <linux/usb/tcpm.h>
+
+struct tcpc_gen_mux_data {
+	struct tcpc_mux_dev mux;
+	struct device *dev;
+	struct mux_control *type_c_mode_mux; /* Type-C cross switch / mux */
+	struct mux_control *usb_role_mux;    /* USB Device / Host mode mux */
+	bool muxes_set;
+};
+
+static int tcpc_gen_mux_set(struct tcpc_mux_dev *mux_dev,
+			    enum tcpc_mux_mode mux_mode,
+			    enum tcpc_usb_switch usb_config,
+			    enum typec_cc_polarity polarity)
+{
+	struct tcpc_gen_mux_data *data =
+		container_of(mux_dev, struct tcpc_gen_mux_data, mux);
+	unsigned int typec_state = MUX_TYPEC_USB;
+	unsigned int usb_state = MUX_USB_DEVICE;
+	int ret;
+
+	/* Put the muxes back in their open (idle) state */
+	if (data->muxes_set) {
+		mux_control_deselect(data->type_c_mode_mux);
+		mux_control_deselect(data->usb_role_mux);
+		data->muxes_set = false;
+	}
+
+	switch (mux_mode) {
+	case TYPEC_MUX_NONE:
+		/* Muxes are in their open state, done. */
+		return 0;
+	case TYPEC_MUX_USB_DEVICE:
+		typec_state = MUX_TYPEC_USB;
+		usb_state = MUX_USB_DEVICE;
+		break;
+	case TYPEC_MUX_USB_HOST:
+		typec_state = MUX_TYPEC_USB;
+		usb_state = MUX_USB_HOST;
+		break;
+	case TYPEC_MUX_DP:
+		typec_state = MUX_TYPEC_DP;
+		break;
+	case TYPEC_MUX_DOCK:
+		typec_state = MUX_TYPEC_USB_AND_DP;
+		usb_state = MUX_USB_HOST;
+		break;
+	}
+
+	if (polarity)
+		typec_state |= MUX_TYPEC_POLARITY_INV;
+
+	ret = mux_control_select(data->type_c_mode_mux, typec_state);
+	if (ret) {
+		dev_err(data->dev, "Error setting Type-C mode mux: %d\n", ret);
+		return ret;
+	}
+
+	ret = mux_control_select(data->usb_role_mux, usb_state);
+	if (ret) {
+		dev_err(data->dev, "Error setting USB role mux: %d\n", ret);
+		mux_control_deselect(data->type_c_mode_mux);
+		return ret;
+	}
+
+	data->muxes_set = true;
+	return 0;
+}
+
+struct tcpc_mux_dev *devm_tcpc_gen_mux_create(struct device *dev)
+{
+	struct tcpc_gen_mux_data *data;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	/* The use of either mux is optional */
+	data->type_c_mode_mux =
+		devm_mux_control_get_optional(dev, "type-c-mode-mux");
+	if (IS_ERR(data->type_c_mode_mux)) {
+		ret = PTR_ERR(data->type_c_mode_mux);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Error getting Type-C mux: %d\n", ret);
+		return ERR_PTR(-ret);
+	}
+
+	data->usb_role_mux = devm_mux_control_get_optional(dev, "usb-role-mux");
+	if (IS_ERR(data->usb_role_mux)) {
+		ret = PTR_ERR(data->usb_role_mux);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Error getting USB role mux: %d\n", ret);
+		return ERR_PTR(-ret);
+	}
+
+	data->dev = dev;
+	data->mux.set = tcpc_gen_mux_set;
+
+	return &data->mux;
+}
+EXPORT_SYMBOL_GPL(devm_tcpc_gen_mux_create);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Generic Type-C mux driver using the mux subsys");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index bc76389ee257..3ad97da5fe16 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -207,4 +207,6 @@ void tcpm_pd_transmit_complete(struct tcpm_port *port,
 void tcpm_pd_hard_reset(struct tcpm_port *port);
 void tcpm_tcpc_reset(struct tcpm_port *port);
 
+struct tcpc_mux_dev *devm_tcpc_gen_mux_create(struct device *dev);
+
 #endif /* __LINUX_USB_TCPM_H */
-- 
2.14.1