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, 147 insertions, 3 deletions

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index 0eee635..abd8342 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -23,6 +23,7 @@
 #include <linux/module.h>
 #include <linux/mfd/core.h>
 #include <linux/mfd/cros_ec.h>
+#include <asm/unaligned.h>
 
 #define CROS_EC_DEV_EC_INDEX 0
 #define CROS_EC_DEV_PD_INDEX 1
@@ -49,11 +50,28 @@ static const struct mfd_cell ec_pd_cell = {
 	.pdata_size = sizeof(pd_p),
 };
 
+static irqreturn_t ec_irq_thread(int irq, void *data)
+{
+	struct cros_ec_device *ec_dev = data;
+	int ret;
+
+	if (device_may_wakeup(ec_dev->dev))
+		pm_wakeup_event(ec_dev->dev, 0);
+
+	ret = cros_ec_get_next_event(ec_dev);
+	if (ret > 0)
+		blocking_notifier_call_chain(&ec_dev->event_notifier,
+					     0, ec_dev);
+	return IRQ_HANDLED;
+}
+
 int cros_ec_register(struct cros_ec_device *ec_dev)
 {
 	struct device *dev = ec_dev->dev;
 	int err = 0;
 
+	BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
+
 	ec_dev->max_request = sizeof(struct ec_params_hello);
 	ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
 	ec_dev->max_passthru = 0;
@@ -70,13 +88,24 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 
 	cros_ec_query_all(ec_dev);
 
+	if (ec_dev->irq) {
+		err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
+					   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					   "chromeos-ec", ec_dev);
+		if (err) {
+			dev_err(dev, "Failed to request IRQ %d: %d",
+				ec_dev->irq, err);
+			return err;
+		}
+	}
+
 	err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
 			      NULL, ec_dev->irq, NULL);
 	if (err) {
 		dev_err(dev,
 			"Failed to register Embedded Controller subdevice %d\n",
 			err);
-		return err;
+		goto fail_mfd;
 	}
 
 	if (ec_dev->max_passthru) {
@@ -94,7 +123,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 			dev_err(dev,
 				"Failed to register Power Delivery subdevice %d\n",
 				err);
-			return err;
+			goto fail_mfd;
 		}
 	}
 
@@ -103,13 +132,18 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		if (err) {
 			mfd_remove_devices(dev);
 			dev_err(dev, "Failed to register sub-devices\n");
-			return err;
+			goto fail_mfd;
 		}
 	}
 
 	dev_info(dev, "Chrome EC device registered\n");
 
 	return 0;
+
+fail_mfd:
+	if (ec_dev->irq)
+		free_irq(ec_dev->irq, ec_dev);
+	return err;
 }
 EXPORT_SYMBOL(cros_ec_register);
 
@@ -136,13 +170,31 @@ int cros_ec_suspend(struct cros_ec_device *ec_dev)
 }
 EXPORT_SYMBOL(cros_ec_suspend);
 
+static void cros_ec_drain_events(struct cros_ec_device *ec_dev)
+{
+	while (cros_ec_get_next_event(ec_dev) > 0)
+		blocking_notifier_call_chain(&ec_dev->event_notifier,
+					     1, ec_dev);
+}
+
 int cros_ec_resume(struct cros_ec_device *ec_dev)
 {
 	enable_irq(ec_dev->irq);
 
+	/*
+	 * In some cases, we need to distinguish between events that occur
+	 * during suspend if the EC is not a wake source. For example,
+	 * keypresses during suspend should be discarded if it does not wake
+	 * the system.
+	 *
+	 * If the EC is not a wake source, drain the event queue and mark them
+	 * as "queued during suspend".
+	 */
 	if (ec_dev->wake_enabled) {
 		disable_irq_wake(ec_dev->irq);
 		ec_dev->wake_enabled = 0;
+	} else {
+		cros_ec_drain_events(ec_dev);
 	}
 
 	return 0;
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 6c084b2..04053fe 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);