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>

1 files changed, 92 insertions, 0 deletions

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 6c084b266651..04053fe1e980 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -19,6 +19,7 @@
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <asm/unaligned.h>
 
 #define EC_COMMAND_RETRIES      50
 
@@ -234,11 +235,44 @@ static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
         return ret;
 }
 
+static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
+        u16 cmd, u32 *mask)
+{
+        struct ec_params_get_cmd_versions *pver;
+        struct ec_response_get_cmd_versions *rver;
+        struct cros_ec_command *msg;
+        int ret;
+
+        msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
+                      GFP_KERNEL);
+        if (!msg)
+                return -ENOMEM;
+
+        msg->version = 0;
+        msg->command = EC_CMD_GET_CMD_VERSIONS;
+        msg->insize = sizeof(*rver);
+        msg->outsize = sizeof(*pver);
+
+        pver = (struct ec_params_get_cmd_versions *)msg->data;
+        pver->cmd = cmd;
+
+        ret = cros_ec_cmd_xfer(ec_dev, msg);
+        if (ret > 0) {
+                rver = (struct ec_response_get_cmd_versions *)msg->data;
+                *mask = rver->version_mask;
+        }
+
+        kfree(msg);
+
+        return ret;
+}
+
 int cros_ec_query_all(struct cros_ec_device *ec_dev)
 {
         struct device *dev = ec_dev->dev;
         struct cros_ec_command *proto_msg;
         struct ec_response_get_protocol_info *proto_info;
+        u32 ver_mask = 0;
         int ret;
 
         proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
@@ -328,6 +362,15 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
                 goto exit;
         }
 
+        /* Probe if MKBP event is supported */
+        ret = cros_ec_get_host_command_version_mask(ec_dev,
+                                                    EC_CMD_GET_NEXT_EVENT,
+                                                    &ver_mask);
+        if (ret < 0 || ver_mask == 0)
+                ec_dev->mkbp_event_supported = 0;
+        else
+                ec_dev->mkbp_event_supported = 1;
+
 exit:
         kfree(proto_msg);
         return ret;
@@ -397,3 +440,52 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
         return ret;
 }
 EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
+
+static int get_next_event(struct cros_ec_device *ec_dev)
+{
+        u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
+        struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
+        int ret;
+
+        msg->version = 0;
+        msg->command = EC_CMD_GET_NEXT_EVENT;
+        msg->insize = sizeof(ec_dev->event_data);
+        msg->outsize = 0;
+
+        ret = cros_ec_cmd_xfer(ec_dev, msg);
+        if (ret > 0) {
+                ec_dev->event_size = ret - 1;
+                memcpy(&ec_dev->event_data, msg->data,
+                       sizeof(ec_dev->event_data));
+        }
+
+        return ret;
+}
+
+static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
+{
+        u8 buffer[sizeof(struct cros_ec_command) +
+                  sizeof(ec_dev->event_data.data)];
+        struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
+
+        msg->version = 0;
+        msg->command = EC_CMD_MKBP_STATE;
+        msg->insize = sizeof(ec_dev->event_data.data);
+        msg->outsize = 0;
+
+        ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
+        ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
+        memcpy(&ec_dev->event_data.data, msg->data,
+               sizeof(ec_dev->event_data.data));
+
+        return ec_dev->event_size;
+}
+
+int cros_ec_get_next_event(struct cros_ec_device *ec_dev)
+{
+        if (ec_dev->mkbp_event_supported)
+                return get_next_event(ec_dev);
+        else
+                return get_keyboard_state_event(ec_dev);
+}
+EXPORT_SYMBOL(cros_ec_get_next_event);