mfd: cros_ec: Add MKBP event support

Newer revisions of the ChromeOS EC add more events besides the keyboard
ones. So handle interrupts in the MFD driver and let consumers register
for notifications for the events they might care.

To keep backward compatibility, if the EC doesn't support MKBP event, we
fall back to the old MKBP key matrix host command.

Cc: Randall Spangler <rspangler@chromium.org>
Cc: Vincent Palatin <vpalatin@chromium.org>
Cc: Benson Leung <bleung@chromium.org>
Signed-off-by: Vic Yang <victoryang@google.com>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

2 files changed, 52 insertions, 0 deletions

diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index d641a18abacb..76f7ef4d3a0d 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -109,6 +109,10 @@ struct cros_ec_command {
  *     should check msg.result for the EC's result code.
  * @pkt_xfer: send packet to EC and get response
  * @lock: one transaction at a time
+ * @mkbp_event_supported: true if this EC supports the MKBP event protocol.
+ * @event_notifier: interrupt event notifier for transport devices.
+ * @event_data: raw payload transferred with the MKBP event.
+ * @event_size: size in bytes of the event data.
  */
 struct cros_ec_device {
 
@@ -137,6 +141,11 @@ struct cros_ec_device {
 	int (*pkt_xfer)(struct cros_ec_device *ec,
 			struct cros_ec_command *msg);
 	struct mutex lock;
+	bool mkbp_event_supported;
+	struct blocking_notifier_head event_notifier;
+
+	struct ec_response_get_next_event event_data;
+	int event_size;
 };
 
 /* struct cros_ec_platform - ChromeOS EC platform information
@@ -269,6 +278,15 @@ int cros_ec_register(struct cros_ec_device *ec_dev);
  */
 int cros_ec_query_all(struct cros_ec_device *ec_dev);
 
+/**
+ * cros_ec_get_next_event -  Fetch next event from the ChromeOS EC
+ *
+ * @ec_dev: Device to fetch event from
+ *
+ * Returns: 0 on success, Linux error number on failure
+ */
+int cros_ec_get_next_event(struct cros_ec_device *ec_dev);
+
 /* sysfs stuff */
 extern struct attribute_group cros_ec_attr_group;
 extern struct attribute_group cros_ec_lightbar_attr_group;
diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
index 7e7a8d4b4551..76728ff37d01 100644
--- a/include/linux/mfd/cros_ec_commands.h
+++ b/include/linux/mfd/cros_ec_commands.h
@@ -1793,6 +1793,40 @@ struct ec_result_keyscan_seq_ctrl {
 	};
 } __packed;
 
+/*
+ * Command for retrieving the next pending MKBP event from the EC device
+ *
+ * The device replies with UNAVAILABLE if there aren't any pending events.
+ */
+#define EC_CMD_GET_NEXT_EVENT 0x67
+
+enum ec_mkbp_event {
+	/* Keyboard matrix changed. The event data is the new matrix state. */
+	EC_MKBP_EVENT_KEY_MATRIX = 0,
+
+	/* New host event. The event data is 4 bytes of host event flags. */
+	EC_MKBP_EVENT_HOST_EVENT = 1,
+
+	/* New Sensor FIFO data. The event data is fifo_info structure. */
+	EC_MKBP_EVENT_SENSOR_FIFO = 2,
+
+	/* Number of MKBP events */
+	EC_MKBP_EVENT_COUNT,
+};
+
+union ec_response_get_next_data {
+	uint8_t   key_matrix[13];
+
+	/* Unaligned */
+	uint32_t  host_event;
+} __packed;
+
+struct ec_response_get_next_event {
+	uint8_t event_type;
+	/* Followed by event data if any */
+	union ec_response_get_next_data data;
+} __packed;
+
 /*****************************************************************************/
 /* Temperature sensor commands */