diff options
Diffstat (limited to 'drivers/pinctrl/devicetree.c')
| -rw-r--r-- | drivers/pinctrl/devicetree.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c new file mode 100644 index 000000000000..fcb1de45473c --- /dev/null +++ b/drivers/pinctrl/devicetree.c @@ -0,0 +1,249 @@ +/* + * Device tree integration for the pin control subsystem + * + * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/device.h> +#include <linux/of.h> +#include <linux/pinctrl/pinctrl.h> +#include <linux/slab.h> + +#include "core.h" +#include "devicetree.h" + +/** + * struct pinctrl_dt_map - mapping table chunk parsed from device tree + * @node: list node for struct pinctrl's @dt_maps field + * @pctldev: the pin controller that allocated this struct, and will free it + * @maps: the mapping table entries + */ +struct pinctrl_dt_map { + struct list_head node; + struct pinctrl_dev *pctldev; + struct pinctrl_map *map; + unsigned num_maps; +}; + +static void dt_free_map(struct pinctrl_dev *pctldev, + struct pinctrl_map *map, unsigned num_maps) +{ + if (pctldev) { + struct pinctrl_ops *ops = pctldev->desc->pctlops; + ops->dt_free_map(pctldev, map, num_maps); + } else { + /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */ + kfree(map); + } +} + +void pinctrl_dt_free_maps(struct pinctrl *p) +{ + struct pinctrl_dt_map *dt_map, *n1; + + list_for_each_entry_safe(dt_map, n1, &p->dt_maps, node) { + pinctrl_unregister_map(dt_map->map); + list_del(&dt_map->node); + dt_free_map(dt_map->pctldev, dt_map->map, + dt_map->num_maps); + kfree(dt_map); + } + + of_node_put(p->dev->of_node); +} + +static int dt_remember_or_free_map(struct pinctrl *p, const char *statename, + struct pinctrl_dev *pctldev, + struct pinctrl_map *map, unsigned num_maps) +{ + int i; + struct pinctrl_dt_map *dt_map; + + /* Initialize common mapping table entry fields */ + for (i = 0; i < num_maps; i++) { + map[i].dev_name = dev_name(p->dev); + map[i].name = statename; + if (pctldev) + map[i].ctrl_dev_name = dev_name(pctldev->dev); + } + + /* Remember the converted mapping table entries */ + dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL); + if (!dt_map) { + dev_err(p->dev, "failed to alloc struct pinctrl_dt_map\n"); + dt_free_map(pctldev, map, num_maps); + return -ENOMEM; + } + + dt_map->pctldev = pctldev; + dt_map->map = map; + dt_map->num_maps = num_maps; + list_add_tail(&dt_map->node, &p->dt_maps); + + return pinctrl_register_map(map, num_maps, false, true); +} + +static struct pinctrl_dev *find_pinctrl_by_of_node(struct device_node *np) +{ + struct pinctrl_dev *pctldev; + + list_for_each_entry(pctldev, &pinctrldev_list, node) + if (pctldev->dev->of_node == np) + return pctldev; + + return NULL; +} + +static int dt_to_map_one_config(struct pinctrl *p, const char *statename, + struct device_node *np_config) +{ + struct device_node *np_pctldev; + struct pinctrl_dev *pctldev; + struct pinctrl_ops *ops; + int ret; + struct pinctrl_map *map; + unsigned num_maps; + + /* Find the pin controller containing np_config */ + np_pctldev = of_node_get(np_config); + for (;;) { + np_pctldev = of_get_next_parent(np_pctldev); + if (!np_pctldev || of_node_is_root(np_pctldev)) { + dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n", + np_config->full_name); + of_node_put(np_pctldev); + /* OK let's just assume this will appear later then */ + return -EPROBE_DEFER; + } + pctldev = find_pinctrl_by_of_node(np_pctldev); + if (pctldev) + break; + } + of_node_put(np_pctldev); + + /* + * Call pinctrl driver to parse device tree node, and + * generate mapping table entries + */ + ops = pctldev->desc->pctlops; + if (!ops->dt_node_to_map) { + dev_err(p->dev, "pctldev %s doesn't support DT\n", + dev_name(pctldev->dev)); + return -ENODEV; + } + ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps); + if (ret < 0) + return ret; + + /* Stash the mapping table chunk away for later use */ + return dt_remember_or_free_map(p, statename, pctldev, map, num_maps); +} + +static int dt_remember_dummy_state(struct pinctrl *p, const char *statename) +{ + struct pinctrl_map *map; + + map = kzalloc(sizeof(*map), GFP_KERNEL); + if (!map) { + dev_err(p->dev, "failed to alloc struct pinctrl_map\n"); + return -ENOMEM; + } + + /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */ + map->type = PIN_MAP_TYPE_DUMMY_STATE; + + return dt_remember_or_free_map(p, statename, NULL, map, 1); +} + +int pinctrl_dt_to_map(struct pinctrl *p) +{ + struct device_node *np = p->dev->of_node; + int state, ret; + char *propname; + struct property *prop; + const char *statename; + const __be32 *list; + int size, config; + phandle phandle; + struct device_node *np_config; + + /* CONFIG_OF enabled, p->dev not instantiated from DT */ + if (!np) { + dev_dbg(p->dev, "no of_node; not parsing pinctrl DT\n"); + return 0; + } + + /* We may store pointers to property names within the node */ + of_node_get(np); + + /* For each defined state ID */ + for (state = 0; ; state++) { + /* Retrieve the pinctrl-* property */ + propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state); + prop = of_find_property(np, propname, &size); + kfree(propname); + if (!prop) + break; + list = prop->value; + size /= sizeof(*list); + + /* Determine whether pinctrl-names property names the state */ + ret = of_property_read_string_index(np, "pinctrl-names", + state, &statename); + /* + * If not, statename is just the integer state ID. But rather + * than dynamically allocate it and have to free it later, + * just point part way into the property name for the string. + */ + if (ret < 0) { + /* strlen("pinctrl-") == 8 */ + statename = prop->name + 8; + } + + /* For every referenced pin configuration node in it */ + for (config = 0; config < size; config++) { + phandle = be32_to_cpup(list++); + + /* Look up the pin configuration node */ + np_config = of_find_node_by_phandle(phandle); + if (!np_config) { + dev_err(p->dev, + "prop %s index %i invalid phandle\n", + prop->name, config); + ret = -EINVAL; + goto err; + } + + /* Parse the node */ + ret = dt_to_map_one_config(p, statename, np_config); + of_node_put(np_config); + if (ret < 0) + goto err; + } + + /* No entries in DT? Generate a dummy state table entry */ + if (!size) { + ret = dt_remember_dummy_state(p, statename); + if (ret < 0) + goto err; + } + } + + return 0; + +err: + pinctrl_dt_free_maps(p); + return ret; +} |