usb: typec: ucsi: Simplified registration and I/O API

Adding more simplified API for interface registration and
read and write operations.

The registration is split into separate creation and
registration phases. That allows the drivers to properly
initialize the interface before registering it if necessary.

The read and write operations are supplied in a completely
separate struct ucsi_operations that is passed to the
ucsi_register() function during registration. The new read
and write operations will work more traditionally so that
the read callback function reads a requested amount of data
from an offset, and the write callback functions write the
given data to the offset. The drivers will have to support
both non-blocking writing and blocking writing. In blocking
writing the driver itself is responsible of waiting for the
completion event.

The new API makes it possible for the drivers to perform
tasks also independently of the core ucsi.c, and that should
allow for example quirks to be handled completely in the
drivers without the need to touch ucsi.c.

The old API is kept until all drivers have been converted to
the new API.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Ajay Gupta <ajayg@nvidia.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191104142435.29960-12-heikki.krogerus@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/ucsi/ucsi.h

@@ -10,6 +10,56 @@
 
 /* -------------------------------------------------------------------------- */
 
+struct ucsi;
+
+/* UCSI offsets (Bytes) */
+#define UCSI_VERSION			0
+#define UCSI_CCI			4
+#define UCSI_CONTROL			8
+#define UCSI_MESSAGE_IN			16
+#define UCSI_MESSAGE_OUT		32
+
+/* Command Status and Connector Change Indication (CCI) bits */
+#define UCSI_CCI_CONNECTOR(_c_)		(((_c_) & GENMASK(7, 0)) >> 1)
+#define UCSI_CCI_LENGTH(_c_)		(((_c_) & GENMASK(15, 8)) >> 8)
+#define UCSI_CCI_NOT_SUPPORTED		BIT(25)
+#define UCSI_CCI_CANCEL_COMPLETE	BIT(26)
+#define UCSI_CCI_RESET_COMPLETE		BIT(27)
+#define UCSI_CCI_BUSY			BIT(28)
+#define UCSI_CCI_ACK_COMPLETE		BIT(29)
+#define UCSI_CCI_ERROR			BIT(30)
+#define UCSI_CCI_COMMAND_COMPLETE	BIT(31)
+
+/**
+ * struct ucsi_operations - UCSI I/O operations
+ * @read: Read operation
+ * @sync_write: Blocking write operation
+ * @async_write: Non-blocking write operation
+ *
+ * Read and write routines for UCSI interface. @sync_write must wait for the
+ * Command Completion Event from the PPM before returning, and @async_write must
+ * return immediately after sending the data to the PPM.
+ */
+struct ucsi_operations {
+	int (*read)(struct ucsi *ucsi, unsigned int offset,
+		    void *val, size_t val_len);
+	int (*sync_write)(struct ucsi *ucsi, unsigned int offset,
+			  const void *val, size_t val_len);
+	int (*async_write)(struct ucsi *ucsi, unsigned int offset,
+			   const void *val, size_t val_len);
+};
+
+struct ucsi *ucsi_create(struct device *dev, const struct ucsi_operations *ops);
+void ucsi_destroy(struct ucsi *ucsi);
+int ucsi_register(struct ucsi *ucsi);
+void ucsi_unregister(struct ucsi *ucsi);
+void *ucsi_get_drvdata(struct ucsi *ucsi);
+void ucsi_set_drvdata(struct ucsi *ucsi, void *data);
+
+void ucsi_connector_change(struct ucsi *ucsi, u8 num);
+
+/* -------------------------------------------------------------------------- */
+
 /* Command Status and Connector Change Indication (CCI) data structure */
 struct ucsi_cci {
 	u8:1; /* reserved */
@@ -207,6 +257,10 @@ struct ucsi_control {
 #define UCSI_ACK_EVENT			1
 #define UCSI_ACK_CMD			2
 
+/* Bits for ACK CC or CI */
+#define UCSI_ACK_CONNECTOR_CHANGE		BIT(16)
+#define UCSI_ACK_COMMAND_COMPLETE		BIT(17)
+
 /* Bits for SET_NOTIFICATION_ENABLE command */
 #define UCSI_ENABLE_NTFY_CMD_COMPLETE		BIT(0)
 #define UCSI_ENABLE_NTFY_EXT_PWR_SRC_CHANGE	BIT(1)
@@ -383,8 +437,12 @@ enum ucsi_status {
 };
 
 struct ucsi {
+	u16 version;
 	struct device *dev;
 	struct ucsi_ppm *ppm;
+	struct driver_data *driver_data;
+
+	const struct ucsi_operations *ops;
 
 	enum ucsi_status status;
 	struct completion complete;