[PATCH v3 12/16] bus: mhi: core: Add uevent support for module autoloading

[Manivannan Sadhasivam]

Add uevent support to MHI bus so that the client drivers can be autoloaded
by udev when the MHI devices gets created. The client drivers are
expected to provide MODULE_DEVICE_TABLE with the MHI id_table struct so
that the alias can be exported.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Reviewed-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
Tested-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
---
 drivers/bus/mhi/core/init.c       |  9 +++++++++
 include/linux/mod_devicetable.h   |  1 +
 scripts/mod/devicetable-offsets.c |  3 +++
 scripts/mod/file2alias.c          | 10 ++++++++++
 4 files changed, 23 insertions(+)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 7bfffa9a5ad1..5fb756ca335e 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -1210,6 +1210,14 @@ void mhi_driver_unregister(struct mhi_driver *mhi_drv)
 }
 EXPORT_SYMBOL_GPL(mhi_driver_unregister);
 
+static int mhi_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct mhi_device *mhi_dev = to_mhi_device(dev);
+
+	return add_uevent_var(env, "MODALIAS=" MHI_DEVICE_MODALIAS_FMT,
+					mhi_dev->chan_name);
+}
+
 static int mhi_match(struct device *dev, struct device_driver *drv)
 {
 	struct mhi_device *mhi_dev = to_mhi_device(dev);
@@ -1236,6 +1244,7 @@ struct bus_type mhi_bus_type = {
 	.name = "mhi",
 	.dev_name = "mhi",
 	.match = mhi_match,
+	.uevent = mhi_uevent,
 };
 
 static int __init mhi_init(void)
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index be15e997fe39..f10e779a3fd0 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -821,6 +821,7 @@ struct wmi_device_id {
 	const void *context;
 };
 
+#define MHI_DEVICE_MODALIAS_FMT "mhi:%s"
 #define MHI_NAME_SIZE 32
 
 /**
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index 054405b90ba4..fe3f4a95cb21 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -231,5 +231,8 @@ int main(void)
 	DEVID(wmi_device_id);
 	DEVID_FIELD(wmi_device_id, guid_string);
 
+	DEVID(mhi_device_id);
+	DEVID_FIELD(mhi_device_id, chan);
+
 	return 0;
 }
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index c91eba751804..cae6a4e471b5 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1335,6 +1335,15 @@ static int do_wmi_entry(const char *filename, void *symval, char *alias)
 	return 1;
 }
 
+/* Looks like: mhi:S */
+static int do_mhi_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD_ADDR(symval, mhi_device_id, chan);
+	sprintf(alias, MHI_DEVICE_MODALIAS_FMT, *chan);
+
+	return 1;
+}
+
 /* Does namelen bytes of name exactly match the symbol? */
 static bool sym_is(const char *name, unsigned namelen, const char *symbol)
 {
@@ -1407,6 +1416,7 @@ static const struct devtable devtable[] = {
 	{"typec", SIZE_typec_device_id, do_typec_entry},
 	{"tee", SIZE_tee_client_device_id, do_tee_entry},
 	{"wmi", SIZE_wmi_device_id, do_wmi_entry},
+	{"mhi", SIZE_mhi_device_id, do_mhi_entry},
 };
 
 /* Create MODULE_ALIAS() statements.
-- 
2.17.1