debugfs: regset32: Add Runtime PM support

Hardware registers of devices under control of power management cannot
be accessed at all times.  If such a device is suspended, register
accesses may lead to undefined behavior, like reading bogus values, or
causing exceptions or system lock-ups.

Extend struct debugfs_regset32 with an optional field to let device
drivers specify the device the registers in the set belong to.  This
allows debugfs_show_regset32() to make sure the device is resumed while
its registers are being read.

Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Niklas Söderlund <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 3d013de..ad41685 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -35,6 +35,7 @@ struct debugfs_regset32 {
 	const struct debugfs_reg32 *regs;
 	int nregs;
 	void __iomem *base;
+	struct device *dev;	/* Optional device for Runtime PM */
 };
 
 extern struct dentry *arch_debugfs_dir;