Rework gpio phandle parsing

Rework gpio phandle parsing

[Grant Likely]

I originally posted this as part of the DT clock bindings.  I'm reposting
now since I've fixed up some bugs and I'm planning to put them into
linux-next.

The DT clock binding patches will be posted separately.

Cheers,
g.


 arch/arm/boot/dts/testcases/tests-phandle.dtsi |   37 ++++++
 arch/arm/boot/dts/testcases/tests.dtsi         |    1 +
 arch/arm/boot/dts/versatile-pb.dts             |    2 +
 arch/microblaze/kernel/reset.c                 |   43 +-------
 arch/powerpc/sysdev/qe_lib/gpio.c              |   42 ++------
 drivers/gpio/gpiolib.c                         |    2 +-
 drivers/of/Kconfig                             |    9 ++
 drivers/of/Makefile                            |    1 +
 drivers/of/base.c                              |  146 ++++++++++++------------
 drivers/of/gpio.c                              |   43 +++----
 drivers/of/selftest.c                          |  139 ++++++++++++++++++++++
 include/asm-generic/gpio.h                     |    6 +-
 include/linux/of.h                             |   11 ++-
 include/linux/of_gpio.h                        |   10 +-
 14 files changed, 313 insertions(+), 179 deletions(-)

[PATCH 1/4] gpio/microblaze: Eliminate duplication of of_get_named_gpio_flags()

[Grant Likely]

of_reset_gpio_handle() is largely a cut-and-paste copy of
of_get_named_gpio_flags(). There really isn't any reason for the
split, so this patch deletes the duplicate function

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Michal Simek <monstr@monstr.eu>
---
 arch/microblaze/kernel/reset.c |   43 +--------------------------------------
 1 files changed, 2 insertions(+), 41 deletions(-)

diff --git a/arch/microblaze/kernel/reset.c b/arch/microblaze/kernel/reset.c
index bd8ccab..88a0163 100644
--- a/arch/microblaze/kernel/reset.c
+++ b/arch/microblaze/kernel/reset.c
@@ -19,50 +19,11 @@
 static int handle; /* reset pin handle */
 static unsigned int reset_val;
 
-static int of_reset_gpio_handle(void)
-{
-	int ret; /* variable which stored handle reset gpio pin */
-	struct device_node *root; /* root node */
-	struct device_node *gpio; /* gpio node */
-	struct gpio_chip *gc;
-	u32 flags;
-	const void *gpio_spec;
-
-	/* find out root node */
-	root = of_find_node_by_path("/");
-
-	/* give me handle for gpio node to be possible allocate pin */
-	ret = of_parse_phandles_with_args(root, "hard-reset-gpios",
-				"#gpio-cells", 0, &gpio, &gpio_spec);
-	if (ret) {
-		pr_debug("%s: can't parse gpios property\n", __func__);
-		goto err0;
-	}
-
-	gc = of_node_to_gpiochip(gpio);
-	if (!gc) {
-		pr_debug("%s: gpio controller %s isn't registered\n",
-			 root->full_name, gpio->full_name);
-		ret = -ENODEV;
-		goto err1;
-	}
-
-	ret = gc->of_xlate(gc, root, gpio_spec, &flags);
-	if (ret < 0)
-		goto err1;
-
-	ret += gc->base;
-err1:
-	of_node_put(gpio);
-err0:
-	pr_debug("%s exited with status %d\n", __func__, ret);
-	return ret;
-}
-
 void of_platform_reset_gpio_probe(void)
 {
 	int ret;
-	handle = of_reset_gpio_handle();
+	handle = of_get_named_gpio(of_find_node_by_path("/"),
+				   "hard-reset-gpios", 0);
 
 	if (!gpio_is_valid(handle)) {
 		printk(KERN_INFO "Skipping unavailable RESET gpio %d (%s)\n",
-- 
1.7.5.4

[PATCH 2/4] gpio/powerpc: Eliminate duplication of of_get_named_gpio_flags()

[Grant Likely]

A large chunk of qe_pin_request() is unnecessarily cut-and-paste
directly from of_get_named_gpio_flags().  This patch cuts out the
duplicate code and replaces it with a call to of_get_gpio().

v2: fixed compile error due to missing gpio_to_chip()

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
---
 arch/powerpc/sysdev/qe_lib/gpio.c |   42 +++++++-----------------------------
 drivers/gpio/gpiolib.c            |    2 +-
 include/asm-generic/gpio.h        |    1 +
 3 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/arch/powerpc/sysdev/qe_lib/gpio.c b/arch/powerpc/sysdev/qe_lib/gpio.c
index e23f23c..521e67a 100644
--- a/arch/powerpc/sysdev/qe_lib/gpio.c
+++ b/arch/powerpc/sysdev/qe_lib/gpio.c
@@ -139,14 +139,10 @@ struct qe_pin {
 struct qe_pin *qe_pin_request(struct device_node *np, int index)
 {
 	struct qe_pin *qe_pin;
-	struct device_node *gpio_np;
 	struct gpio_chip *gc;
 	struct of_mm_gpio_chip *mm_gc;
 	struct qe_gpio_chip *qe_gc;
 	int err;
-	int size;
-	const void *gpio_spec;
-	const u32 *gpio_cells;
 	unsigned long flags;
 
 	qe_pin = kzalloc(sizeof(*qe_pin), GFP_KERNEL);
@@ -155,45 +151,25 @@ struct qe_pin *qe_pin_request(struct device_node *np, int index)
 		return ERR_PTR(-ENOMEM);
 	}
 
-	err = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index,
-					  &gpio_np, &gpio_spec);
-	if (err) {
-		pr_debug("%s: can't parse gpios property\n", __func__);
+	err = of_get_gpio(np, index);
+	if (err < 0)
+		goto err0;
+	gc = gpio_to_chip(err);
+	if (WARN_ON(!gc))
 		goto err0;
-	}
 
-	if (!of_device_is_compatible(gpio_np, "fsl,mpc8323-qe-pario-bank")) {
+	if (!of_device_is_compatible(gc->of_node, "fsl,mpc8323-qe-pario-bank")) {
 		pr_debug("%s: tried to get a non-qe pin\n", __func__);
 		err = -EINVAL;
-		goto err1;
-	}
-
-	gc = of_node_to_gpiochip(gpio_np);
-	if (!gc) {
-		pr_debug("%s: gpio controller %s isn't registered\n",
-			 np->full_name, gpio_np->full_name);
-		err = -ENODEV;
-		goto err1;
-	}
-
-	gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
-	if (!gpio_cells || size != sizeof(*gpio_cells) ||
-			*gpio_cells != gc->of_gpio_n_cells) {
-		pr_debug("%s: wrong #gpio-cells for %s\n",
-			 np->full_name, gpio_np->full_name);
-		err = -EINVAL;
-		goto err1;
+		goto err0;
 	}
 
-	err = gc->of_xlate(gc, np, gpio_spec, NULL);
-	if (err < 0)
-		goto err1;
-
 	mm_gc = to_of_mm_gpio_chip(gc);
 	qe_gc = to_qe_gpio_chip(mm_gc);
 
 	spin_lock_irqsave(&qe_gc->lock, flags);
 
+	err -= gc->base;
 	if (test_and_set_bit(QE_PIN_REQUESTED, &qe_gc->pin_flags[err]) == 0) {
 		qe_pin->controller = qe_gc;
 		qe_pin->num = err;
@@ -206,8 +182,6 @@ struct qe_pin *qe_pin_request(struct device_node *np, int index)
 
 	if (!err)
 		return qe_pin;
-err1:
-	of_node_put(gpio_np);
 err0:
 	kfree(qe_pin);
 	pr_debug("%s failed with status %d\n", __func__, err);
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a971e3d..dc315e9 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -114,7 +114,7 @@ static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
 }
 
 /* caller holds gpio_lock *OR* gpio is marked as requested */
-static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
+struct gpio_chip *gpio_to_chip(unsigned gpio)
 {
 	return gpio_desc[gpio].chip;
 }
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 8c86210..6b10bdc 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -135,6 +135,7 @@ struct gpio_chip {
 
 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
 			unsigned offset);
+extern struct gpio_chip *gpio_to_chip(unsigned gpio);
 extern int __must_check gpiochip_reserve(int start, int ngpio);
 
 /* add/remove chips */
-- 
1.7.5.4

[PATCH 3/4] of: create of_phandle_args to simplify return of phandle parsing data

[Grant Likely]

of_parse_phandle_with_args() needs to return quite a bit of data.  Rather
than making each datum a separate **out_ argument, this patch creates
struct of_phandle_args to contain all the returned data and reworks the
user of the function.  This patch also enables of_parse_phandle_with_args()
to return the device node pointer for the phandle node.

This patch also ends up being fairly major surgery to
of_parse_handle_with_args().  The existing structure didn't work well
when extending to use of_phandle_args, and I discovered bugs during testing.
I also took the opportunity to rename the function to be like the
existing of_parse_phandle().

v2: - moved declaration of of_phandle_args to fix compile on non-DT builds
    - fixed incorrect index in example usage
    - fixed incorrect return code handling for empty entries

Reviewed-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 drivers/of/base.c          |  146 ++++++++++++++++++++++---------------------
 drivers/of/gpio.c          |   43 ++++++-------
 include/asm-generic/gpio.h |    5 +-
 include/linux/of.h         |   11 +++-
 include/linux/of_gpio.h    |   10 ++-
 5 files changed, 112 insertions(+), 103 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 9b6588e..c6db9ab 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -824,17 +824,19 @@ of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
 EXPORT_SYMBOL(of_parse_phandle);
 
 /**
- * of_parse_phandles_with_args - Find a node pointed by phandle in a list
+ * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
  * @np:		pointer to a device tree node containing a list
  * @list_name:	property name that contains a list
  * @cells_name:	property name that specifies phandles' arguments count
  * @index:	index of a phandle to parse out
- * @out_node:	optional pointer to device_node struct pointer (will be filled)
- * @out_args:	optional pointer to arguments pointer (will be filled)
+ * @out_args:	optional pointer to output arguments structure (will be filled)
  *
  * This function is useful to parse lists of phandles and their arguments.
- * Returns 0 on success and fills out_node and out_args, on error returns
- * appropriate errno value.
+ * Returns 0 on success and fills out_args, on error returns appropriate
+ * errno value.
+ *
+ * Caller is responsible to call of_node_put() on the returned out_args->node
+ * pointer.
  *
  * Example:
  *
@@ -851,94 +853,96 @@ EXPORT_SYMBOL(of_parse_phandle);
  * }
  *
  * To get a device_node of the `node2' node you may call this:
- * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
+ * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
  */
-int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
+int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
 				const char *cells_name, int index,
-				struct device_node **out_node,
-				const void **out_args)
+				struct of_phandle_args *out_args)
 {
-	int ret = -EINVAL;
-	const __be32 *list;
-	const __be32 *list_end;
-	int size;
-	int cur_index = 0;
+	const __be32 *list, *list_end;
+	int size, cur_index = 0;
+	uint32_t count = 0;
 	struct device_node *node = NULL;
-	const void *args = NULL;
+	phandle phandle;
 
+	/* Retrieve the phandle list property */
 	list = of_get_property(np, list_name, &size);
-	if (!list) {
-		ret = -ENOENT;
-		goto err0;
-	}
+	if (!list)
+		return -EINVAL;
 	list_end = list + size / sizeof(*list);
 
+	/* Loop over the phandles until all the requested entry is found */
 	while (list < list_end) {
-		const __be32 *cells;
-		phandle phandle;
+		count = 0;
 
+		/*
+		 * If phandle is 0, then it is an empty entry with no
+		 * arguments.  Skip forward to the next entry.
+		 */
 		phandle = be32_to_cpup(list++);
-		args = list;
-
-		/* one cell hole in the list = <>; */
-		if (!phandle)
-			goto next;
-
-		node = of_find_node_by_phandle(phandle);
-		if (!node) {
-			pr_debug("%s: could not find phandle\n",
-				 np->full_name);
-			goto err0;
-		}
+		if (phandle) {
+			/*
+			 * Find the provider node and parse the #*-cells
+			 * property to determine the argument length
+			 */
+			node = of_find_node_by_phandle(phandle);
+			if (!node) {
+				pr_err("%s: could not find phandle\n",
+					 np->full_name);
+				break;
+			}
+			if (of_property_read_u32(node, cells_name, &count)) {
+				pr_err("%s: could not get %s for %s\n",
+					 np->full_name, cells_name,
+					 node->full_name);
+				break;
+			}
 
-		cells = of_get_property(node, cells_name, &size);
-		if (!cells || size != sizeof(*cells)) {
-			pr_debug("%s: could not get %s for %s\n",
-				 np->full_name, cells_name, node->full_name);
-			goto err1;
+			/*
+			 * Make sure that the arguments actually fit in the
+			 * remaining property data length
+			 */
+			if (list + count > list_end) {
+				pr_err("%s: arguments longer than property\n",
+					 np->full_name);
+				break;
+			}
 		}
 
-		list += be32_to_cpup(cells);
-		if (list > list_end) {
-			pr_debug("%s: insufficient arguments length\n",
-				 np->full_name);
-			goto err1;
+		/*
+		 * All of the error cases above bail out of the loop, so at
+		 * this point, the parsing is successful. If the requested
+		 * index matches, then fill the out_args structure and return,
+		 * or return -ENOENT for an empty entry.
+		 */
+		if (cur_index == index) {
+			if (!phandle)
+				return -ENOENT;
+
+			if (out_args) {
+				int i;
+				if (WARN_ON(count > MAX_PHANDLE_ARGS))
+					count = MAX_PHANDLE_ARGS;
+				out_args->np = node;
+				out_args->args_count = count;
+				for (i = 0; i < count; i++)
+					out_args->args[i] = be32_to_cpup(list++);
+			}
+			return 0;
 		}
-next:
-		if (cur_index == index)
-			break;
 
 		of_node_put(node);
 		node = NULL;
-		args = NULL;
+		list += count;
 		cur_index++;
 	}
 
-	if (!node) {
-		/*
-		 * args w/o node indicates that the loop above has stopped at
-		 * the 'hole' cell. Report this differently.
-		 */
-		if (args)
-			ret = -EEXIST;
-		else
-			ret = -ENOENT;
-		goto err0;
-	}
-
-	if (out_node)
-		*out_node = node;
-	if (out_args)
-		*out_args = args;
-
-	return 0;
-err1:
-	of_node_put(node);
-err0:
-	pr_debug("%s failed with status %d\n", __func__, ret);
-	return ret;
+	/* Loop exited without finding a valid entry; return an error */
+	if (node)
+		of_node_put(node);
+	return -EINVAL;
 }
-EXPORT_SYMBOL(of_parse_phandles_with_args);
+EXPORT_SYMBOL(of_parse_phandle_with_args);
 
 /**
  * prom_add_property - Add a property to a node
diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
index ef0105f..244a2b0 100644
--- a/drivers/of/gpio.c
+++ b/drivers/of/gpio.c
@@ -35,32 +35,27 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname,
                            int index, enum of_gpio_flags *flags)
 {
 	int ret;
-	struct device_node *gpio_np;
 	struct gpio_chip *gc;
-	int size;
-	const void *gpio_spec;
-	const __be32 *gpio_cells;
+	struct of_phandle_args gpiospec;
 
-	ret = of_parse_phandles_with_args(np, propname, "#gpio-cells", index,
-					  &gpio_np, &gpio_spec);
+	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
+					 &gpiospec);
 	if (ret) {
 		pr_debug("%s: can't parse gpios property\n", __func__);
 		goto err0;
 	}
 
-	gc = of_node_to_gpiochip(gpio_np);
+	gc = of_node_to_gpiochip(gpiospec.np);
 	if (!gc) {
 		pr_debug("%s: gpio controller %s isn't registered\n",
-			 np->full_name, gpio_np->full_name);
+			 np->full_name, gpiospec.np->full_name);
 		ret = -ENODEV;
 		goto err1;
 	}
 
-	gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
-	if (!gpio_cells || size != sizeof(*gpio_cells) ||
-			be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) {
+	if (gpiospec.args_count != gc->of_gpio_n_cells) {
 		pr_debug("%s: wrong #gpio-cells for %s\n",
-			 np->full_name, gpio_np->full_name);
+			 np->full_name, gpiospec.np->full_name);
 		ret = -EINVAL;
 		goto err1;
 	}
@@ -69,13 +64,13 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname,
 	if (flags)
 		*flags = 0;
 
-	ret = gc->of_xlate(gc, np, gpio_spec, flags);
+	ret = gc->of_xlate(gc, &gpiospec, flags);
 	if (ret < 0)
 		goto err1;
 
 	ret += gc->base;
 err1:
-	of_node_put(gpio_np);
+	of_node_put(gpiospec.np);
 err0:
 	pr_debug("%s exited with status %d\n", __func__, ret);
 	return ret;
@@ -105,8 +100,8 @@ unsigned int of_gpio_count(struct device_node *np)
 	do {
 		int ret;
 
-		ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells",
-						  cnt, NULL, NULL);
+		ret = of_parse_phandle_with_args(np, "gpios", "#gpio-cells",
+						 cnt, NULL);
 		/* A hole in the gpios = <> counts anyway. */
 		if (ret < 0 && ret != -EEXIST)
 			break;
@@ -127,12 +122,9 @@ EXPORT_SYMBOL(of_gpio_count);
  * gpio chips. This function performs only one sanity check: whether gpio
  * is less than ngpios (that is specified in the gpio_chip).
  */
-int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
-			 const void *gpio_spec, u32 *flags)
+int of_gpio_simple_xlate(struct gpio_chip *gc,
+			 const struct of_phandle_args *gpiospec, u32 *flags)
 {
-	const __be32 *gpio = gpio_spec;
-	const u32 n = be32_to_cpup(gpio);
-
 	/*
 	 * We're discouraging gpio_cells < 2, since that way you'll have to
 	 * write your own xlate function (that will have to retrive the GPIO
@@ -144,13 +136,16 @@ int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
 		return -EINVAL;
 	}
 
-	if (n > gc->ngpio)
+	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
+		return -EINVAL;
+
+	if (gpiospec->args[0] > gc->ngpio)
 		return -EINVAL;
 
 	if (flags)
-		*flags = be32_to_cpu(gpio[1]);
+		*flags = gpiospec->args[1];
 
-	return n;
+	return gpiospec->args[0];
 }
 EXPORT_SYMBOL(of_gpio_simple_xlate);
 
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 6b10bdc..d466c8d 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -4,6 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/errno.h>
+#include <linux/of.h>
 
 #ifdef CONFIG_GPIOLIB
 
@@ -128,8 +129,8 @@ struct gpio_chip {
 	 */
 	struct device_node *of_node;
 	int of_gpio_n_cells;
-	int (*of_xlate)(struct gpio_chip *gc, struct device_node *np,
-		        const void *gpio_spec, u32 *flags);
+	int (*of_xlate)(struct gpio_chip *gc,
+		        const struct of_phandle_args *gpiospec, u32 *flags);
 #endif
 };
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 4948552..ea44fd7 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -65,6 +65,13 @@ struct device_node {
 #endif
 };
 
+#define MAX_PHANDLE_ARGS 8
+struct of_phandle_args {
+	struct device_node *np;
+	int args_count;
+	uint32_t args[MAX_PHANDLE_ARGS];
+};
+
 #ifdef CONFIG_OF
 
 /* Pointer for first entry in chain of all nodes. */
@@ -230,9 +237,9 @@ extern int of_modalias_node(struct device_node *node, char *modalias, int len);
 extern struct device_node *of_parse_phandle(struct device_node *np,
 					    const char *phandle_name,
 					    int index);
-extern int of_parse_phandles_with_args(struct device_node *np,
+extern int of_parse_phandle_with_args(struct device_node *np,
 	const char *list_name, const char *cells_name, int index,
-	struct device_node **out_node, const void **out_args);
+	struct of_phandle_args *out_args);
 
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 52280a2..b254052 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -18,6 +18,7 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/gpio.h>
+#include <linux/of.h>
 
 struct device_node;
 
@@ -57,8 +58,9 @@ extern int of_mm_gpiochip_add(struct device_node *np,
 extern void of_gpiochip_add(struct gpio_chip *gc);
 extern void of_gpiochip_remove(struct gpio_chip *gc);
 extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
-extern int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
-				const void *gpio_spec, u32 *flags);
+extern int of_gpio_simple_xlate(struct gpio_chip *gc,
+				const struct of_phandle_args *gpiospec,
+				u32 *flags);
 
 #else /* CONFIG_OF_GPIO */
 
@@ -75,8 +77,8 @@ static inline unsigned int of_gpio_count(struct device_node *np)
 }
 
 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
-				       struct device_node *np,
-				       const void *gpio_spec, u32 *flags)
+				       const struct of_phandle_args *gpiospec,
+				       u32 *flags)
 {
 	return -ENOSYS;
 }
-- 
1.7.5.4

[PATCH 4/4] of: Add device tree selftests

[Grant Likely]

Add some runtime test cases for the library of device tree parsing functions.

v2: - Add testcase for phandle with 0 args
    - Don't run testcases if testcase data isn't present in device tree

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/boot/dts/testcases/tests-phandle.dtsi |   37 +++++++
 arch/arm/boot/dts/testcases/tests.dtsi         |    1 +
 arch/arm/boot/dts/versatile-pb.dts             |    2 +
 drivers/of/Kconfig                             |    9 ++
 drivers/of/Makefile                            |    1 +
 drivers/of/selftest.c                          |  139 ++++++++++++++++++++++++
 6 files changed, 189 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/boot/dts/testcases/tests-phandle.dtsi
 create mode 100644 arch/arm/boot/dts/testcases/tests.dtsi
 create mode 100644 drivers/of/selftest.c

diff --git a/arch/arm/boot/dts/testcases/tests-phandle.dtsi b/arch/arm/boot/dts/testcases/tests-phandle.dtsi
new file mode 100644
index 0000000..ec0c4e6
--- /dev/null
+++ b/arch/arm/boot/dts/testcases/tests-phandle.dtsi
@@ -0,0 +1,37 @@
+
+/ {
+	testcase-data {
+		phandle-tests {
+			provider0: provider0 {
+				#phandle-cells = <0>;
+			};
+
+			provider1: provider1 {
+				#phandle-cells = <1>;
+			};
+
+			provider2: provider2 {
+				#phandle-cells = <2>;
+			};
+
+			provider3: provider3 {
+				#phandle-cells = <3>;
+			};
+
+			consumer-a {
+				phandle-list =	<&provider1 1>,
+						<&provider2 2 0>,
+						<0>,
+						<&provider3 4 4 3>,
+						<&provider2 5 100>,
+						<&provider0>,
+						<&provider1 7>;
+				phandle-list-names = "first", "second", "third";
+
+				phandle-list-bad-phandle = <12345678 0 0>;
+				phandle-list-bad-args = <&provider2 1 0>,
+							<&provider3 0>;
+			};
+		};
+	};
+};
diff --git a/arch/arm/boot/dts/testcases/tests.dtsi b/arch/arm/boot/dts/testcases/tests.dtsi
new file mode 100644
index 0000000..a7c5067
--- /dev/null
+++ b/arch/arm/boot/dts/testcases/tests.dtsi
@@ -0,0 +1 @@
+/include/ "tests-phandle.dtsi"
diff --git a/arch/arm/boot/dts/versatile-pb.dts b/arch/arm/boot/dts/versatile-pb.dts
index 8a614e3..1664610 100644
--- a/arch/arm/boot/dts/versatile-pb.dts
+++ b/arch/arm/boot/dts/versatile-pb.dts
@@ -46,3 +46,5 @@
 		};
 	};
 };
+
+/include/ "testcases/tests.dtsi"
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index cac63c9..268163d 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -15,6 +15,15 @@ config PROC_DEVICETREE
 	  an image of the device tree that the kernel copies from Open
 	  Firmware or other boot firmware. If unsure, say Y here.
 
+config OF_SELFTEST
+	bool "Device Tree Runtime self tests"
+	help
+	  This option builds in test cases for the device tree infrastructure
+	  that are executed one at boot time, and the results dumped to the
+	  console.
+
+	  If unsure, say N here, but this option is safe to enable.
+
 config OF_FLATTREE
 	bool
 	select DTC
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index dccb117..a73f5a5 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_OF_GPIO)   += gpio.o
 obj-$(CONFIG_OF_I2C)	+= of_i2c.o
 obj-$(CONFIG_OF_NET)	+= of_net.o
 obj-$(CONFIG_OF_SPI)	+= of_spi.o
+obj-$(CONFIG_OF_SELFTEST) += selftest.o
 obj-$(CONFIG_OF_MDIO)	+= of_mdio.o
 obj-$(CONFIG_OF_PCI)	+= of_pci.o
 obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o
diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
new file mode 100644
index 0000000..9d2b480
--- /dev/null
+++ b/drivers/of/selftest.c
@@ -0,0 +1,139 @@
+/*
+ * Self tests for device tree subsystem
+ */
+
+#define pr_fmt(fmt) "### %s(): " fmt, __func__
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+static bool selftest_passed = true;
+#define selftest(result, fmt, ...) { \
+	selftest_passed &= (result); \
+	if (!(result)) \
+		pr_err("FAIL %s:%i " fmt, __FILE__, __LINE__, ##__VA_ARGS__); \
+}
+
+static void __init of_selftest_parse_phandle_with_args(void)
+{
+	struct device_node *np;
+	struct of_phandle_args args;
+	int rc, i;
+	bool passed_all = true;
+
+	pr_info("start\n");
+	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
+	if (!np) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	for (i = 0; i < 7; i++) {
+		bool passed = true;
+		rc = of_parse_phandle_with_args(np, "phandle-list",
+						"#phandle-cells", i, &args);
+
+		/* Test the values from tests-phandle.dtsi */
+		switch (i) {
+		case 0:
+			passed &= !rc;
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == (i + 1));
+			break;
+		case 1:
+			passed &= !rc;
+			passed &= (args.args_count == 2);
+			passed &= (args.args[0] == (i + 1));
+			passed &= (args.args[1] == 0);
+			break;
+		case 2:
+			passed &= (rc == -ENOENT);
+			break;
+		case 3:
+			passed &= !rc;
+			passed &= (args.args_count == 3);
+			passed &= (args.args[0] == (i + 1));
+			passed &= (args.args[1] == 4);
+			passed &= (args.args[2] == 3);
+			break;
+		case 4:
+			passed &= !rc;
+			passed &= (args.args_count == 2);
+			passed &= (args.args[0] == (i + 1));
+			passed &= (args.args[1] == 100);
+			break;
+		case 5:
+			passed &= !rc;
+			passed &= (args.args_count == 0);
+			break;
+		case 6:
+			passed &= !rc;
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == (i + 1));
+			break;
+		case 7:
+			passed &= (rc == -EINVAL);
+			break;
+		default:
+			passed = false;
+		}
+
+		if (!passed) {
+			int j;
+			pr_err("index %i - data error on node %s rc=%i regs=[",
+				i, args.np->full_name, rc);
+			for (j = 0; j < args.args_count; j++)
+				printk(" %i", args.args[j]);
+			printk(" ]\n");
+
+			passed_all = false;
+		}
+	}
+
+	/* Check for missing list property */
+	rc = of_parse_phandle_with_args(np, "phandle-list-missing",
+					"#phandle-cells", 0, &args);
+	passed_all &= (rc == -EINVAL);
+
+	/* Check for missing cells property */
+	rc = of_parse_phandle_with_args(np, "phandle-list",
+					"#phandle-cells-missing", 0, &args);
+	passed_all &= (rc == -EINVAL);
+
+	/* Check for bad phandle in list */
+	rc = of_parse_phandle_with_args(np, "phandle-list-bad-phandle",
+					"#phandle-cells", 0, &args);
+	passed_all &= (rc == -EINVAL);
+
+	/* Check for incorrectly formed argument list */
+	rc = of_parse_phandle_with_args(np, "phandle-list-bad-args",
+					"#phandle-cells", 1, &args);
+	passed_all &= (rc == -EINVAL);
+
+	pr_info("end - %s\n", passed_all ? "PASS" : "FAIL");
+}
+
+static int __init of_selftest(void)
+{
+	struct device_node *np;
+
+	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
+	if (!np) {
+		pr_info("No testcase data in device tree; not running tests\n");
+		return 0;
+	}
+	of_node_put(np);
+
+	pr_info("start of selftest - you will see error messages\n");
+	of_selftest_parse_phandle_with_args();
+	pr_info("end of selftest - %s\n", selftest_passed ? "PASS" : "FAIL");
+	return 0;
+}
+late_initcall(of_selftest);
-- 
1.7.5.4