pinctrl: factor pin control handles over to the core

This moves the per-devices struct pinctrl handles and device map
over from the pinmux part of the subsystem to the core pinctrl part.
This makes the device handles core infrastructure with the goal of
using these handles also for pin configuration, so that device
drivers (or boards etc) will need one and only one handle to the
pin control core.

Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 596 insertions, 2 deletions

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 75c6a6bb6c0a..ec32c545f07f 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1,7 +1,7 @@
 /*
  * Core driver for the pin control subsystem
  *
- * Copyright (C) 2011 ST-Ericsson SA
+ * Copyright (C) 2011-2012 ST-Ericsson SA
  * Written on behalf of Linaro for ST-Ericsson
  * Based on bits of regulator core, gpio core and clk core
  *
@@ -30,10 +30,30 @@
 #include "pinmux.h"
 #include "pinconf.h"
 
+/**
+ * struct pinctrl_hog - a list item to stash control hogs
+ * @node: pin control hog list node
+ * @map: map entry responsible for this hogging
+ * @pmx: the pin control hogged by this item
+ */
+struct pinctrl_hog {
+	struct list_head node;
+	struct pinctrl_map const *map;
+	struct pinctrl *p;
+};
+
 /* Global list of pin control devices */
 static DEFINE_MUTEX(pinctrldev_list_mutex);
 static LIST_HEAD(pinctrldev_list);
 
+/* List of pin controller handles */
+static DEFINE_MUTEX(pinctrl_list_mutex);
+static LIST_HEAD(pinctrl_list);
+
+/* Global pinctrl maps */
+static struct pinctrl_map *pinctrl_maps;
+static unsigned pinctrl_maps_num;
+
 const char *pinctrl_dev_get_name(struct pinctrl_dev *pctldev)
 {
 	/* We're not allowed to register devices without name */
@@ -337,6 +357,476 @@ int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
 	return -EINVAL;
 }
 
+/**
+ * pinctrl_request_gpio() - request a single pin to be used in as GPIO
+ * @gpio: the GPIO pin number from the GPIO subsystem number space
+ *
+ * This function should *ONLY* be used from gpiolib-based GPIO drivers,
+ * as part of their gpio_request() semantics, platforms and individual drivers
+ * shall *NOT* request GPIO pins to be muxed in.
+ */
+int pinctrl_request_gpio(unsigned gpio)
+{
+	struct pinctrl_dev *pctldev;
+	struct pinctrl_gpio_range *range;
+	int ret;
+	int pin;
+
+	ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
+	if (ret)
+		return -EINVAL;
+
+	/* Convert to the pin controllers number space */
+	pin = gpio - range->base + range->pin_base;
+
+	return pinmux_request_gpio(pctldev, range, pin, gpio);
+}
+EXPORT_SYMBOL_GPL(pinctrl_request_gpio);
+
+/**
+ * pinctrl_free_gpio() - free control on a single pin, currently used as GPIO
+ * @gpio: the GPIO pin number from the GPIO subsystem number space
+ *
+ * This function should *ONLY* be used from gpiolib-based GPIO drivers,
+ * as part of their gpio_free() semantics, platforms and individual drivers
+ * shall *NOT* request GPIO pins to be muxed out.
+ */
+void pinctrl_free_gpio(unsigned gpio)
+{
+	struct pinctrl_dev *pctldev;
+	struct pinctrl_gpio_range *range;
+	int ret;
+	int pin;
+
+	ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
+	if (ret)
+		return;
+
+	/* Convert to the pin controllers number space */
+	pin = gpio - range->base + range->pin_base;
+
+	return pinmux_free_gpio(pctldev, pin, range);
+}
+EXPORT_SYMBOL_GPL(pinctrl_free_gpio);
+
+static int pinctrl_gpio_direction(unsigned gpio, bool input)
+{
+	struct pinctrl_dev *pctldev;
+	struct pinctrl_gpio_range *range;
+	int ret;
+	int pin;
+
+	ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
+	if (ret)
+		return ret;
+
+	/* Convert to the pin controllers number space */
+	pin = gpio - range->base + range->pin_base;
+
+	return pinmux_gpio_direction(pctldev, range, pin, input);
+}
+
+/**
+ * pinctrl_gpio_direction_input() - request a GPIO pin to go into input mode
+ * @gpio: the GPIO pin number from the GPIO subsystem number space
+ *
+ * This function should *ONLY* be used from gpiolib-based GPIO drivers,
+ * as part of their gpio_direction_input() semantics, platforms and individual
+ * drivers shall *NOT* touch pin control GPIO calls.
+ */
+int pinctrl_gpio_direction_input(unsigned gpio)
+{
+	return pinctrl_gpio_direction(gpio, true);
+}
+EXPORT_SYMBOL_GPL(pinctrl_gpio_direction_input);
+
+/**
+ * pinctrl_gpio_direction_output() - request a GPIO pin to go into output mode
+ * @gpio: the GPIO pin number from the GPIO subsystem number space
+ *
+ * This function should *ONLY* be used from gpiolib-based GPIO drivers,
+ * as part of their gpio_direction_output() semantics, platforms and individual
+ * drivers shall *NOT* touch pin control GPIO calls.
+ */
+int pinctrl_gpio_direction_output(unsigned gpio)
+{
+	return pinctrl_gpio_direction(gpio, false);
+}
+EXPORT_SYMBOL_GPL(pinctrl_gpio_direction_output);
+
+/**
+ * pinctrl_get() - retrieves the pin controller handle for a certain device
+ * @dev: the device to get the pin controller handle for
+ * @name: an optional specific control mapping name or NULL, the name is only
+ *	needed if you want to have more than one mapping per device, or if you
+ *	need an anonymous pin control (not tied to any specific device)
+ */
+struct pinctrl *pinctrl_get(struct device *dev, const char *name)
+{
+	struct pinctrl_map const *map = NULL;
+	struct pinctrl_dev *pctldev = NULL;
+	const char *devname = NULL;
+	struct pinctrl *p;
+	bool found_map;
+	unsigned num_maps = 0;
+	int ret = -ENODEV;
+	int i;
+
+	/* We must have dev or ID or both */
+	if (!dev && !name)
+		return ERR_PTR(-EINVAL);
+
+	if (dev)
+		devname = dev_name(dev);
+
+	pr_debug("get pin control handle %s for device %s\n", name,
+		 devname ? devname : "(none)");
+
+	/*
+	 * create the state cookie holder struct pinctrl for each
+	 * mapping, this is what consumers will get when requesting
+	 * a pin control handle with pinctrl_get()
+	 */
+	p = kzalloc(sizeof(struct pinctrl), GFP_KERNEL);
+	if (p == NULL)
+		return ERR_PTR(-ENOMEM);
+	mutex_init(&p->mutex);
+	pinmux_init_pinctrl_handle(p);
+
+	/* Iterate over the pin control maps to locate the right ones */
+	for (i = 0; i < pinctrl_maps_num; i++) {
+		map = &pinctrl_maps[i];
+		found_map = false;
+
+		/*
+		 * First, try to find the pctldev given in the map
+		 */
+		pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
+		if (!pctldev) {
+			pr_warning("could not find a pinctrl device for pinmux function %s, fishy, they shall all have one\n",
+				   map->function);
+			pr_warning("given pinctrl device name: %s",
+				   map->ctrl_dev_name);
+
+			/* Continue to check the other mappings anyway... */
+			continue;
+		}
+
+		pr_debug("in map, found pctldev %s to handle function %s",
+			 dev_name(pctldev->dev), map->function);
+
+
+		/*
+		 * If we're looking for a specific named map, this must match,
+		 * else we loop and look for the next.
+		 */
+		if (name != NULL) {
+			if (map->name == NULL)
+				continue;
+			if (strcmp(map->name, name))
+				continue;
+		}
+
+		/*
+		 * This is for the case where no device name is given, we
+		 * already know that the function name matches from above
+		 * code.
+		 */
+		if (!map->dev_name && (name != NULL))
+			found_map = true;
+
+		/* If the mapping has a device set up it must match */
+		if (map->dev_name &&
+		    (!devname || !strcmp(map->dev_name, devname)))
+			/* MATCH! */
+			found_map = true;
+
+		/* If this map is applicable, then apply it */
+		if (found_map) {
+			ret = pinmux_apply_muxmap(pctldev, p, dev,
+						   devname, map);
+			if (ret) {
+				kfree(p);
+				return ERR_PTR(ret);
+			}
+			num_maps++;
+		}
+	}
+
+	/* We should have atleast one map, right */
+	if (!num_maps) {
+		pr_err("could not find any mux maps for device %s, ID %s\n",
+		       devname ? devname : "(anonymous)",
+		       name ? name : "(undefined)");
+		kfree(p);
+		return ERR_PTR(-EINVAL);
+	}
+
+	pr_debug("found %u mux maps for device %s, UD %s\n",
+		 num_maps,
+		 devname ? devname : "(anonymous)",
+		 name ? name : "(undefined)");
+
+	/* Add the pinmux to the global list */
+	mutex_lock(&pinctrl_list_mutex);
+	list_add(&p->node, &pinctrl_list);
+	mutex_unlock(&pinctrl_list_mutex);
+
+	return p;
+}
+EXPORT_SYMBOL_GPL(pinctrl_get);
+
+/**
+ * pinctrl_put() - release a previously claimed pin control handle
+ * @p: a pin control handle previously claimed by pinctrl_get()
+ */
+void pinctrl_put(struct pinctrl *p)
+{
+	if (p == NULL)
+		return;
+
+	mutex_lock(&p->mutex);
+	if (p->usecount)
+		pr_warn("releasing pin control handle with active users!\n");
+	/* Free the groups and all acquired pins */
+	pinmux_put(p);
+	mutex_unlock(&p->mutex);
+
+	/* Remove from list */
+	mutex_lock(&pinctrl_list_mutex);
+	list_del(&p->node);
+	mutex_unlock(&pinctrl_list_mutex);
+
+	kfree(p);
+}
+EXPORT_SYMBOL_GPL(pinctrl_put);
+
+/**
+ * pinctrl_enable() - enable a certain pin controller setting
+ * @p: the pin control handle to enable, previously claimed by pinctrl_get()
+ */
+int pinctrl_enable(struct pinctrl *p)
+{
+	int ret = 0;
+
+	if (p == NULL)
+		return -EINVAL;
+	mutex_lock(&p->mutex);
+	if (p->usecount++ == 0) {
+		ret = pinmux_enable(p);
+		if (ret)
+			p->usecount--;
+	}
+	mutex_unlock(&p->mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pinctrl_enable);
+
+/**
+ * pinctrl_disable() - disable a certain pin control setting
+ * @p: the pin control handle to disable, previously claimed by pinctrl_get()
+ */
+void pinctrl_disable(struct pinctrl *p)
+{
+	if (p == NULL)
+		return;
+
+	mutex_lock(&p->mutex);
+	if (--p->usecount == 0) {
+		pinmux_disable(p);
+	}
+	mutex_unlock(&p->mutex);
+}
+EXPORT_SYMBOL_GPL(pinctrl_disable);
+
+/**
+ * pinctrl_register_mappings() - register a set of pin controller mappings
+ * @maps: the pincontrol mappings table to register, this should be marked with
+ *	__initdata so it can be discarded after boot, this function will
+ *	perform a shallow copy for the mapping entries.
+ * @num_maps: the number of maps in the mapping table
+ *
+ * Only call this once during initialization of your machine, the function is
+ * tagged as __init and won't be callable after init has completed. The map
+ * passed into this function will be owned by the pinmux core and cannot be
+ * freed.
+ */
+int __init pinctrl_register_mappings(struct pinctrl_map const *maps,
+				     unsigned num_maps)
+{
+	void *tmp_maps;
+	int i;
+
+	pr_debug("add %d pinmux maps\n", num_maps);
+
+	/* First sanity check the new mapping */
+	for (i = 0; i < num_maps; i++) {
+		if (!maps[i].name) {
+			pr_err("failed to register map %d: no map name given\n",
+					i);
+			return -EINVAL;
+		}
+
+		if (!maps[i].ctrl_dev_name) {
+			pr_err("failed to register map %s (%d): no pin control device given\n",
+			       maps[i].name, i);
+			return -EINVAL;
+		}
+
+		if (!maps[i].function) {
+			pr_err("failed to register map %s (%d): no function ID given\n",
+					maps[i].name, i);
+			return -EINVAL;
+		}
+
+		if (!maps[i].dev_name)
+			pr_debug("add system map %s function %s with no device\n",
+				 maps[i].name,
+				 maps[i].function);
+		else
+			pr_debug("register map %s, function %s\n",
+				 maps[i].name,
+				 maps[i].function);
+	}
+
+	/*
+	 * Make a copy of the map array - string pointers will end up in the
+	 * kernel const section anyway so these do not need to be deep copied.
+	 */
+	if (!pinctrl_maps_num) {
+		/* On first call, just copy them */
+		tmp_maps = kmemdup(maps,
+				   sizeof(struct pinctrl_map) * num_maps,
+				   GFP_KERNEL);
+		if (!tmp_maps)
+			return -ENOMEM;
+	} else {
+		/* Subsequent calls, reallocate array to new size */
+		size_t oldsize = sizeof(struct pinctrl_map) * pinctrl_maps_num;
+		size_t newsize = sizeof(struct pinctrl_map) * num_maps;
+
+		tmp_maps = krealloc(pinctrl_maps,
+				    oldsize + newsize, GFP_KERNEL);
+		if (!tmp_maps)
+			return -ENOMEM;
+		memcpy((tmp_maps + oldsize), maps, newsize);
+	}
+
+	pinctrl_maps = tmp_maps;
+	pinctrl_maps_num += num_maps;
+	return 0;
+}
+
+/* Hog a single map entry and add to the hoglist */
+static int pinctrl_hog_map(struct pinctrl_dev *pctldev,
+			   struct pinctrl_map const *map)
+{
+	struct pinctrl_hog *hog;
+	struct pinctrl *p;
+	int ret;
+
+	if (map->dev_name) {
+		/*
+		 * TODO: the day we have device tree support, we can
+		 * traverse the device tree and hog to specific device nodes
+		 * without any problems, so then we can hog pinmuxes for
+		 * all devices that just want a static pin mux at this point.
+		 */
+		dev_err(pctldev->dev, "map %s wants to hog a non-system pinmux, this is not going to work\n",
+				map->name);
+		return -EINVAL;
+	}
+
+	hog = kzalloc(sizeof(struct pinctrl_hog), GFP_KERNEL);
+	if (!hog)
+		return -ENOMEM;
+
+	p = pinctrl_get(NULL, map->name);
+	if (IS_ERR(p)) {
+		kfree(hog);
+		dev_err(pctldev->dev,
+			"could not get the %s pin control mapping for hogging\n",
+			map->name);
+		return PTR_ERR(p);
+	}
+
+	ret = pinctrl_enable(p);
+	if (ret) {
+		pinctrl_put(p);
+		kfree(hog);
+		dev_err(pctldev->dev,
+			"could not enable the %s pin control mapping for hogging\n",
+			map->name);
+		return ret;
+	}
+
+	hog->map = map;
+	hog->p = p;
+
+	dev_info(pctldev->dev, "hogged map %s, function %s\n", map->name,
+		 map->function);
+	mutex_lock(&pctldev->pinctrl_hogs_lock);
+	list_add(&hog->node, &pctldev->pinctrl_hogs);
+	mutex_unlock(&pctldev->pinctrl_hogs_lock);
+
+	return 0;
+}
+
+/**
+ * pinctrl_hog_maps() - hog specific map entries on controller device
+ * @pctldev: the pin control device to hog entries on
+ *
+ * When the pin controllers are registered, there may be some specific pinmux
+ * map entries that need to be hogged, i.e. get+enabled until the system shuts
+ * down.
+ */
+int pinctrl_hog_maps(struct pinctrl_dev *pctldev)
+{
+	struct device *dev = pctldev->dev;
+	const char *devname = dev_name(dev);
+	int ret;
+	int i;
+
+	INIT_LIST_HEAD(&pctldev->pinctrl_hogs);
+	mutex_init(&pctldev->pinctrl_hogs_lock);
+
+	for (i = 0; i < pinctrl_maps_num; i++) {
+		struct pinctrl_map const *map = &pinctrl_maps[i];
+
+		if (!map->hog_on_boot)
+			continue;
+
+		if (map->ctrl_dev_name &&
+		    !strcmp(map->ctrl_dev_name, devname)) {
+			/* OK time to hog! */
+			ret = pinctrl_hog_map(pctldev, map);
+			if (ret)
+				return ret;
+		}
+	}
+	return 0;
+}
+
+/**
+ * pinctrl_unhog_maps() - unhog specific map entries on controller device
+ * @pctldev: the pin control device to unhog entries on
+ */
+void pinctrl_unhog_maps(struct pinctrl_dev *pctldev)
+{
+	struct list_head *node, *tmp;
+
+	mutex_lock(&pctldev->pinctrl_hogs_lock);
+	list_for_each_safe(node, tmp, &pctldev->pinctrl_hogs) {
+		struct pinctrl_hog *hog =
+			list_entry(node, struct pinctrl_hog, node);
+		pinctrl_disable(hog->p);
+		pinctrl_put(hog->p);
+		list_del(node);
+		kfree(hog);
+	}
+	mutex_unlock(&pctldev->pinctrl_hogs_lock);
+}
+
 #ifdef CONFIG_DEBUG_FS
 
 static int pinctrl_pins_show(struct seq_file *s, void *what)
@@ -427,6 +917,43 @@ static int pinctrl_gpioranges_show(struct seq_file *s, void *what)
 	return 0;
 }
 
+static int pinctrl_maps_show(struct seq_file *s, void *what)
+{
+	int i;
+
+	seq_puts(s, "Pinctrl maps:\n");
+
+	for (i = 0; i < pinctrl_maps_num; i++) {
+		struct pinctrl_map const *map = &pinctrl_maps[i];
+
+		seq_printf(s, "%s:\n", map->name);
+		if (map->dev_name)
+			seq_printf(s, "  device: %s\n",
+				   map->dev_name);
+		else
+			seq_printf(s, "  SYSTEM MUX\n");
+		seq_printf(s, "  controlling device %s\n",
+			   map->ctrl_dev_name);
+		seq_printf(s, "  function: %s\n", map->function);
+		seq_printf(s, "  group: %s\n", map->group ? map->group :
+			   "(default)");
+	}
+	return 0;
+}
+
+static int pinmux_hogs_show(struct seq_file *s, void *what)
+{
+	struct pinctrl_dev *pctldev = s->private;
+	struct pinctrl_hog *hog;
+
+	seq_puts(s, "Pin control map hogs held by device\n");
+
+	list_for_each_entry(hog, &pctldev->pinctrl_hogs, node)
+		seq_printf(s, "%s\n", hog->map->name);
+
+	return 0;
+}
+
 static int pinctrl_devices_show(struct seq_file *s, void *what)
 {
 	struct pinctrl_dev *pctldev;
@@ -450,6 +977,32 @@ static int pinctrl_devices_show(struct seq_file *s, void *what)
 	return 0;
 }
 
+static int pinctrl_show(struct seq_file *s, void *what)
+{
+	struct pinctrl *p;
+
+	seq_puts(s, "Requested pin control handlers their pinmux maps:\n");
+	list_for_each_entry(p, &pinctrl_list, node) {
+		struct pinctrl_dev *pctldev = p->pctldev;
+
+		if (!pctldev) {
+			seq_puts(s, "NO PIN CONTROLLER DEVICE\n");
+			continue;
+		}
+
+		seq_printf(s, "device: %s",
+			   pinctrl_dev_get_name(p->pctldev));
+
+		pinmux_dbg_show(s, p);
+
+		seq_printf(s, " users: %u map-> %s\n",
+			   p->usecount,
+			   p->dev ? dev_name(p->dev) : "(system)");
+	}
+
+	return 0;
+}
+
 static int pinctrl_pins_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, pinctrl_pins_show, inode->i_private);
@@ -465,11 +1018,26 @@ static int pinctrl_gpioranges_open(struct inode *inode, struct file *file)
 	return single_open(file, pinctrl_gpioranges_show, inode->i_private);
 }
 
+static int pinctrl_maps_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pinctrl_maps_show, inode->i_private);
+}
+
+static int pinmux_hogs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pinmux_hogs_show, inode->i_private);
+}
+
 static int pinctrl_devices_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, pinctrl_devices_show, NULL);
 }
 
+static int pinctrl_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pinctrl_show, NULL);
+}
+
 static const struct file_operations pinctrl_pins_ops = {
 	.open		= pinctrl_pins_open,
 	.read		= seq_read,
@@ -491,6 +1059,20 @@ static const struct file_operations pinctrl_gpioranges_ops = {
 	.release	= single_release,
 };
 
+static const struct file_operations pinctrl_maps_ops = {
+	.open		= pinctrl_maps_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static const struct file_operations pinmux_hogs_ops = {
+	.open		= pinmux_hogs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 static const struct file_operations pinctrl_devices_ops = {
 	.open		= pinctrl_devices_open,
 	.read		= seq_read,
@@ -498,6 +1080,13 @@ static const struct file_operations pinctrl_devices_ops = {
 	.release	= single_release,
 };
 
+static const struct file_operations pinctrl_ops = {
+	.open		= pinctrl_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 static struct dentry *debugfs_root;
 
 static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
@@ -519,6 +1108,10 @@ static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
 			    device_root, pctldev, &pinctrl_groups_ops);
 	debugfs_create_file("gpio-ranges", S_IFREG | S_IRUGO,
 			    device_root, pctldev, &pinctrl_gpioranges_ops);
+	debugfs_create_file("pinctrl-maps", S_IFREG | S_IRUGO,
+			    device_root, pctldev, &pinctrl_maps_ops);
+	debugfs_create_file("pinmux-hogs", S_IFREG | S_IRUGO,
+			    device_root, pctldev, &pinmux_hogs_ops);
 	pinmux_init_device_debugfs(device_root, pctldev);
 	pinconf_init_device_debugfs(device_root, pctldev);
 }
@@ -539,7 +1132,8 @@ static void pinctrl_init_debugfs(void)
 
 	debugfs_create_file("pinctrl-devices", S_IFREG | S_IRUGO,
 			    debugfs_root, NULL, &pinctrl_devices_ops);
-	pinmux_init_debugfs(debugfs_root);
+	debugfs_create_file("pinctrl-handles", S_IFREG | S_IRUGO,
+			    debugfs_root, NULL, &pinctrl_ops);
 }
 
 #else /* CONFIG_DEBUG_FS */