The
touchscreen and touchpad of CrBP 2013 works in Trisquel, which uses
Linux-libre 3.13, but they don't work with the deblobbed mainline
kernel.

It works if changing reject_firmware_nowait to request_firmware_nowait
in atmel_mxt_ts.c, and I think the kernel is still libre after this
change:

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
b/drivers/input/touchscreen/atmel_mxt_ts.c
index e4220f2..b81f621 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -2035,7 +2035,7 @@ static int mxt_initialize(struct mxt_data *data)
if (error)
goto err_free_object_table;

- error = reject_firmware_nowait(THIS_MODULE, true, MXT_CFG_NAME,
+ error = request_firmware_nowait(THIS_MODULE, true, MXT_CFG_NAME,
&client->dev, GFP_KERNEL, data,
mxt_config_cb);
if (error) {

I've sent a mail to Linux-libre mailing list.
http://www.fsfla.org/pipermail/linux-libre/2015-November/003202.html