[PATCH v2] HID: logitech-hidpp: prefix the name with Logitech

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

Current names are reported as "K750", "M705", and it can be misleading
for the users when they look at their input device list.

Prefixing the names with "Logitech " makes things better.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---

Changes in v2:
- renamed PREFIX_SIZE into PREFIX_LENGTH
- changed "name_length + PREFIX_LENGTH;" into "PREFIX_LENGTH + name_length;"
- rebased on Peter's last patch series

 drivers/hid/hid-logitech-hidpp.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 2f420c0..274dbb7 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -282,6 +282,33 @@ static inline bool hidpp_report_is_connect_event(struct hidpp_report *report)
 		(report->rap.sub_id == 0x41);
 }
 
+/**
+ * hidpp_prefix_name() prefixes the current given name with "Logitech ".
+ */
+static void hidpp_prefix_name(char **name, int name_length)
+{
+#define PREFIX_LENGTH 9 /* "Logitech " */
+
+	int new_length;
+	char *new_name;
+
+	if (name_length > PREFIX_LENGTH &&
+	    strncmp(*name, "Logitech ", PREFIX_LENGTH) == 0)
+		/* The prefix has is already in the name */
+		return;
+
+	new_length = PREFIX_LENGTH + name_length;
+	new_name = kzalloc(new_length, GFP_KERNEL);
+	if (!new_name)
+		return;
+
+	snprintf(new_name, new_length, "Logitech %s", *name);
+
+	kfree(*name);
+
+	*name = new_name;
+}
+
 /* -------------------------------------------------------------------------- */
 /* HIDP++ 1.0 commands                                                        */
 /* -------------------------------------------------------------------------- */
@@ -321,6 +348,10 @@ static char *hidpp_get_unifying_name(struct hidpp_device *hidpp_dev)
 		return NULL;
 
 	memcpy(name, &response.rap.params[2], len);
+
+	/* include the terminating '\0' */
+	hidpp_prefix_name(&name, len + 1);
+
 	return name;
 }
 
@@ -498,6 +529,9 @@ static char *hidpp_get_device_name(struct hidpp_device *hidpp)
 		index += ret;
 	}
 
+	/* include the terminating '\0' */
+	hidpp_prefix_name(&name, __name_length + 1);
+
 	return name;
 }
 
-- 
2.1.0