[PATCH v3 10/13] of: add a generic pinmux helper
Stephen Warren
swarren at nvidia.com
Fri Aug 26 09:43:41 EST 2011
From: Jamie Iles <jamie at jamieiles.com>
This patch adds a helper function of_pinmux_parse() that can be used to
extract common pinmux configuration to avoid each platform implementing
a parsing loop. Platforms supply the node containing the pinmux
definitions and a platform specific callback for configuring a pingroup.
Signed-off-by: Jamie Iles <jamie at jamieiles.com>
[swarren: Added support for pins property, added parse() callback, use
dev_err instead of pr_err, related minor changes]
Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
drivers/of/Kconfig | 5 ++
drivers/of/Makefile | 1 +
drivers/of/of_pinmux.c | 109 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_pinmux.h | 74 ++++++++++++++++++++++++++++++
4 files changed, 189 insertions(+), 0 deletions(-)
create mode 100644 drivers/of/of_pinmux.c
create mode 100644 include/linux/of_pinmux.h
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index cac63c9..71a19a3 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -81,4 +81,9 @@ config OF_PCI_IRQ
help
OpenFirmware PCI IRQ routing helpers
+config OF_PINMUX
+ def_bool y
+ help
+ OpenFirmware pin multiplexing helpers
+
endmenu # OF
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index dccb117..0666ff3 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_OF_SPI) += of_spi.o
obj-$(CONFIG_OF_MDIO) += of_mdio.o
obj-$(CONFIG_OF_PCI) += of_pci.o
obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o
+obj-$(CONFIG_OF_PINMUX) += of_pinmux.o
diff --git a/drivers/of/of_pinmux.c b/drivers/of/of_pinmux.c
new file mode 100644
index 0000000..8050b8b
--- /dev/null
+++ b/drivers/of/of_pinmux.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2011 Picochip Ltd., Jamie Iles
+ * Copyright (c) 2011 NVIDIA, Inc.
+ *
+ * Generic pinmux bindings for device tree.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_iter_prop.h>
+#include <linux/of_pinmux.h>
+
+/**
+ * of_pinmux_parse - configure a set of pinmux groups for a pinmux controller
+ *
+ * @controller: the controller to configure the pinmux entries for. This
+ * defines the controller device node and the callback for configuring
+ * the pingroups.
+ *
+ * This helper loops over all of the child nodes of a pinmux controller and
+ * collects the configuration for each pinmux group. A pinmux group is
+ * defined as one or more pins that are configured to a common function. This
+ * handles common properties that many platforms may implement, but for
+ * platform specific properties these may be handled in the configure
+ * callback.
+ */
+int of_pinmux_parse(const struct of_pinmux_ctrl *ctrl,
+ struct of_pinmux_cfg *cfg)
+{
+ struct device_node *np;
+
+ if (!ctrl || !ctrl->dev || !ctrl->node || !ctrl->configure)
+ return -EINVAL;
+
+ for_each_child_of_node(ctrl->node, np) {
+ int ret;
+ bool hadpins = 0;
+ struct of_iter_string_prop iter;
+
+ cfg->node = np;
+
+ ret = of_property_read_string(np, "function",
+ &cfg->function);
+ if (ret < 0) {
+ dev_err(ctrl->dev, "no function for node %s\n",
+ np->name);
+ continue;
+ }
+
+ cfg->flags &= 0;
+
+ if (of_find_property(np, "pull-up", NULL))
+ cfg->flags |= OF_PINMUX_PULL_UP;
+ if (of_find_property(np, "pull-down", NULL))
+ cfg->flags |= OF_PINMUX_PULL_DOWN;
+
+ if ((cfg->flags & OF_PINMUX_PULL_MASK) ==
+ OF_PINMUX_PULL_MASK) {
+ dev_warn(ctrl->dev, "node %s has both "
+ "pull-up and pull-down properties - "
+ "defaulting to no pull\n",
+ np->name);
+ cfg->flags &= ~OF_PINMUX_PULL_MASK;
+ }
+
+ if (of_find_property(np, "tristate", NULL))
+ cfg->flags |= OF_PINMUX_TRISTATE;
+
+ if (ctrl->parse && ctrl->parse(ctrl, cfg)) {
+ dev_warn(ctrl->dev,
+ "failed to parse node %s\n",
+ np->name);
+ continue;
+ }
+
+ for_each_string_property_value(iter, np, "pins") {
+ hadpins = 1;
+
+ cfg->pin = iter.value;
+
+ dev_dbg(ctrl->dev,
+ "configure pin %s func=%s flags=0x%lx\n",
+ cfg->pin, cfg->function, cfg->flags);
+ if (ctrl->configure(ctrl, cfg))
+ dev_warn(ctrl->dev,
+ "failed to configure pin %s\n",
+ cfg->pin);
+ }
+
+ if (!hadpins)
+ dev_warn(ctrl->dev, "no pins for node %s\n",
+ np->name);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_pinmux_parse);
diff --git a/include/linux/of_pinmux.h b/include/linux/of_pinmux.h
new file mode 100644
index 0000000..7ccddcf
--- /dev/null
+++ b/include/linux/of_pinmux.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2011 Picochip Ltd., Jamie Iles
+ * Copyright (c) 2011 NVIDIA, Inc.
+ *
+ * Generic pinmux bindings for device tree.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#ifndef __OF_PINMUX_H__
+#define __OF_PINMUX_H__
+
+struct device_node;
+
+#define OF_PINMUX_PULL_UP (1 << 0)
+#define OF_PINMUX_PULL_DOWN (1 << 1)
+#define OF_PINMUX_TRISTATE (1 << 2)
+
+#define OF_PINMUX_PULL_MASK (OF_PINMUX_PULL_UP | OF_PINMUX_PULL_DOWN)
+
+/**
+ * struct of_pinmux_cfg - configuration state for a single pinmux entry.
+ *
+ * @function: the name of the function that the pinmux entry should be
+ * configured to.
+ * @pin: the device_node of the pinmux entry that should be configured.
+ * Platform specific properties that aren't in the generic binding may be
+ * obtained from this device node.
+ * @flags: flags for common pinmux options such as pull and tristate.
+ */
+struct of_pinmux_cfg {
+ struct device_node *node;
+ const char *pin;
+ const char *function;
+ unsigned long flags;
+};
+
+/**
+ * struct of_pinmux_ctrl - platform specific pinmux control state.
+ *
+ * @pinmux: the pinmux device node. All child nodes are required to be the
+ * pinmux entry definitions. Depending on the platform, this may either be
+ * a single pin or a group of pins where they can be set to a common
+ * function.
+ * @configure: platform specific callback to configure the pinmux entry.
+ */
+struct of_pinmux_ctrl {
+ struct device *dev;
+ struct device_node *node;
+ int (*parse)(const struct of_pinmux_ctrl *ctrl,
+ struct of_pinmux_cfg *cfg);
+ int (*configure)(const struct of_pinmux_ctrl *ctrl,
+ const struct of_pinmux_cfg *cfg);
+};
+
+#ifdef CONFIG_OF
+extern int of_pinmux_parse(const struct of_pinmux_ctrl *ctrl,
+ struct of_pinmux_cfg *cfg);
+#else
+static inline int of_pinmux_parse(const struct of_pinmux_ctrl *ctrl,
+ struct of_pinmux_cfg *cfg)
+{
+ return -ENOSYS;
+}
+#endif /* CONFIG_OF */
+
+#endif /* __OF_PINMUX_H__ */
--
1.7.0.4
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