spi: dw: Make debugfs name unique between instances

BugLink: http://bugs.launchpad.net/bugs/1710646

[ Upstream commit 13288bdf ]

Some system have multiple dw devices. Currently the driver uses a
fixed name for the debugfs dir. Append dev name to the debugfs dir
name to make it unique.
Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/spi/spi-dw.c

@@ -107,7 +107,10 @@ static const struct file_operations dw_spi_regs_ops = {
 
 static int dw_spi_debugfs_init(struct dw_spi *dws)
 {
-	dws->debugfs = debugfs_create_dir("dw_spi", NULL);
+	char name[128];
+
+	snprintf(name, 128, "dw_spi-%s", dev_name(&dws->master->dev));
+	dws->debugfs = debugfs_create_dir(name, NULL);
 	if (!dws->debugfs)
 		return -ENOMEM;