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Subject[PATCH 1/4] pinctrl: Introduce generic #pinctrl-cells and pinctrl_parse_index_with_args
Date
Introduce #pinctrl-cells helper binding and generic helper functions
pinctrl_count_index_with_args() and pinctrl_parse_index_with_args().

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
.../bindings/pinctrl/pinctrl-bindings.txt | 44 ++++++-
drivers/pinctrl/devicetree.c | 144 +++++++++++++++++++++
drivers/pinctrl/devicetree.h | 21 +++
3 files changed, 208 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
--- a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
@@ -97,6 +97,11 @@ For example:
};

== Pin controller devices ==
+Required properties: See the pin controller driver specific documentation
+
+Optional properties:
+#pinctrl-cells: Number of pin control cells in addition to the index within the
+ pin controller device instance

Pin controller devices should contain the pin configuration nodes that client
devices reference.
@@ -119,7 +124,8 @@ For example:

The contents of each of those pin configuration child nodes is defined
entirely by the binding for the individual pin controller device. There
-exists no common standard for this content.
+exists no common standard for this content. The pinctrl framework only
+provides generic helper bindings that the pin controller driver can use.

The pin configuration nodes need not be direct children of the pin controller
device; they may be grandchildren, for example. Whether this is legal, and
@@ -156,6 +162,42 @@ state_2_node_a {
pins = "mfio29", "mfio30";
};

+Optionally an altenative binding can be used if more suitable depending on the
+pin controller hardware. For hardaware where there is a large number of identical
+pin controller instances, naming each pin and function can easily become
+unmaintainable. This is especially the case if the same controller is used for
+different pins and functions depending on the SoC revision and packaging.
+
+For cases like this, the pin controller driver may use pinctrl-pin-array helper
+binding with a hardware based index and a number of pin configuration values:
+
+pincontroller {
+ ... /* Standard DT properties for the device itself elided */
+ #pinctrl-cells = <2>;
+
+ state_0_node_a {
+ pinctrl-pin-array = <
+ 0 A_DELAY_PS(0) G_DELAY_PS(120)
+ 4 A_DELAY_PS(0) G_DELAY_PS(360)
+ ...
+ >;
+ };
+ ...
+};
+
+Above #pinctrl-cells specifies the number of value cells in addition to the
+index of the registers. This is similar to the interrupts-extended binding with
+one exception. There is no need to specify the phandle for each entry as that
+is already known as the defined pins are always children of the pin controller
+node. Further having the phandle pointing to another pin controller would not
+currently work as the pinctrl framework uses named modes to group pins for each
+pin control device.
+
+The index for pinctrl-pin-array must relate to the hardware for the pinctrl
+registers, and must not be a virtual index of pin instances. The reason for
+this is to avoid mapping of the index in the dts files and the pin controller
+driver as it can change.
+
== Generic pin configuration node content ==

Many data items that are represented in a pin configuration node are common
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -253,3 +253,147 @@ int pinctrl_dt_to_map(struct pinctrl *p)
pinctrl_dt_free_maps(p);
return ret;
}
+
+/*
+ * For pinctrl binding, typically #pinctrl-cells is for the pin controller
+ * device, so either parent or grandparent. See pinctrl-bindings.txt.
+ */
+static int pinctrl_find_cells_size(const struct device_node *np)
+{
+ const char *cells_name = "#pinctrl-cells";
+ int cells_size, error;
+
+ error = of_property_read_u32(np->parent, cells_name, &cells_size);
+ if (error) {
+ error = of_property_read_u32(np->parent->parent,
+ cells_name, &cells_size);
+ if (error)
+ return -ENOENT;
+ }
+
+ return cells_size;
+}
+
+/**
+ * pinctrl_get_list_and_count - Gets the list and it's cell size and number
+ * @np: pointer to device node with the property
+ * @list_name: property that contains the list
+ * @list: pointer for the list found
+ * @cells_size: pointer for the cell size found
+ * @nr_elements: pointer for the number of elements found
+ *
+ * Typically np is a single pinctrl entry containing the list.
+ */
+static int pinctrl_get_list_and_count(const struct device_node *np,
+ const char *list_name,
+ const __be32 **list,
+ int *cells_size,
+ int *nr_elements)
+{
+ int size;
+
+ *cells_size = 0;
+ *nr_elements = 0;
+
+ *list = of_get_property(np, list_name, &size);
+ if (!*list)
+ return -ENOENT;
+
+ *cells_size = pinctrl_find_cells_size(np);
+ if (*cells_size < 0)
+ return -ENOENT;
+
+ /* First element is always the index within the pinctrl device */
+ *nr_elements = (size / sizeof(**list)) / (*cells_size + 1);
+
+ return 0;
+}
+
+/**
+ * pinctrl_count_index_with_args - Count number of elements in a pinctrl entry
+ * @np: pointer to device node with the property
+ * @list_name: property that contains the list
+ *
+ * Counts the number of elements in a pinctrl array consisting of an index
+ * within the controller and a number of u32 entries specified for each
+ * entry. Note that device_node is always for the parent pin controller device.
+ */
+int pinctrl_count_index_with_args(const struct device_node *np,
+ const char *list_name)
+{
+ const __be32 *list;
+ int size, nr_cells, error;
+
+ error = pinctrl_get_list_and_count(np, list_name, &list,
+ &nr_cells, &size);
+ if (error)
+ return error;
+
+ return size;
+}
+EXPORT_SYMBOL_GPL(pinctrl_count_index_with_args);
+
+/**
+ * pinctrl_copy_args - Populates of_phandle_args based on index
+ * @np: pointer to device node with the property
+ * @list: pointer to a list with the elements
+ * @index: entry within the list of elements
+ * @nr_cells: number of cells in the list
+ * @nr_elem: number of elements for each entry in the list
+ * @out_args: returned values
+ *
+ * Populates the of_phandle_args based on the index in the list.
+ */
+static int pinctrl_copy_args(const struct device_node *np,
+ const __be32 *list,
+ int index, int nr_cells, int nr_elem,
+ struct of_phandle_args *out_args)
+{
+ int i;
+
+ memset(out_args, 0, sizeof(*out_args));
+ out_args->np = (struct device_node *)np;
+ out_args->args_count = nr_cells + 1;
+
+ if (index >= nr_elem)
+ return -EINVAL;
+
+ list += index * (nr_cells + 1);
+
+ for (i = 0; i < nr_cells + 1; i++)
+ out_args->args[i] = be32_to_cpup(list++);
+
+ return 0;
+}
+
+/**
+ * pinctrl_parse_index_with_args - Find a node pointed by index in a list
+ * @np: pointer to device node with the property
+ * @list_name: property that contains the list
+ * @index: index within the list
+ * @out_arts: entries in the list pointed by index
+ *
+ * Finds the selected element in a pinctrl array consisting of an index
+ * within the controller and a number of u32 entries specified for each
+ * entry. Note that device_node is always for the parent pin controller device.
+ */
+int pinctrl_parse_index_with_args(const struct device_node *np,
+ const char *list_name, int index,
+ struct of_phandle_args *out_args)
+{
+ const __be32 *list;
+ int nr_elem, nr_cells, error;
+
+ error = pinctrl_get_list_and_count(np, list_name, &list,
+ &nr_cells, &nr_elem);
+ if (error || !nr_cells)
+ return error;
+
+ error = pinctrl_copy_args(np, list, index, nr_cells, nr_elem,
+ out_args);
+ if (error)
+ return error;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pinctrl_parse_index_with_args);
diff --git a/drivers/pinctrl/devicetree.h b/drivers/pinctrl/devicetree.h
--- a/drivers/pinctrl/devicetree.h
+++ b/drivers/pinctrl/devicetree.h
@@ -21,6 +21,13 @@
void pinctrl_dt_free_maps(struct pinctrl *p);
int pinctrl_dt_to_map(struct pinctrl *p);

+int pinctrl_count_index_with_args(const struct device_node *np,
+ const char *list_name);
+
+int pinctrl_parse_index_with_args(const struct device_node *np,
+ const char *list_name, int index,
+ struct of_phandle_args *out_args);
+
#else

static inline int pinctrl_dt_to_map(struct pinctrl *p)
@@ -32,4 +39,18 @@ static inline void pinctrl_dt_free_maps(struct pinctrl *p)
{
}

+static inline int pinctrl_count_index_with_args(const struct device_node *np,
+ const char *list_name)
+{
+ return -ENODEV;
+}
+
+static inline int
+pinctrl_parse_index_with_args(const struct device_node *np,
+ const char *list_name, int index,
+ struct of_phandle_args *out_args)
+{
+ return -ENODEV;
+}
+
#endif
--
2.10.2
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