On Thu, May 18, 2017 at 01:30:06PM +0800, Dong Aisheng wrote:

quoted

quoted

diff --git a/arch/arm/mach-imx/pm-imx7ulp.c b/arch/arm/mach-imx/pm-imx7ulp.c
new file mode 100644
index 0000000..df5d6b6
--- /dev/null
+++ b/arch/arm/mach-imx/pm-imx7ulp.c

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ * Copyright (C) 2017 NXP
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define SMC_PMCTRL		0x10
+#define BP_PMCTRL_PSTOPO        16
+#define PSTOPO_PSTOP3		0x3
+
+void __init imx7ulp_pm_init(void)
+{
+	struct device_node *np;
+	void __iomem *smc1_base;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,imx7ulp-smc1");

so actually there no dt-binding for this compatible, because there is no driver?

Yes, probably we'd better add another binding doc for it under
Documentation/devicetree/bindings/arm/freescale/.
And there's another fsl,aips-bus also has no binding doc, i'm not sure
whether we need add a binding doc it as well. It seems already exist
on many imx dts files.

Shawn,
your suggestion?

Strictly speaking, every compatible should be documented.  But in
reality, some compatibles not used by kernel may be missing the
documentation.  You're welcomed to add them.

Shawn