一、数据结构
struct pinctrl_setting_mux {
unsigned group;
unsigned func;
};
struct pinctrl_setting_configs {
unsigned group_or_pin;
unsigned long *configs;
unsigned num_configs;
};
struct pinctrl_setting {
struct list_head node;
enum pinctrl_map_type type;
struct pinctrl_dev *pctldev;
const char *dev_name;
union {
struct pinctrl_setting_mux mux;
struct pinctrl_setting_configs configs;
} data;
};
struct pinctrl_state {
struct list_head node;
const char *name;
struct list_head settings;
};
struct pinctrl_dt_map {
struct list_head node;
struct pinctrl_dev *pctldev;
struct pinctrl_map *map;
unsigned num_maps;
};
struct pinctrl {
struct list_head node;
struct device *dev;
struct list_head states;
struct pinctrl_state *state;
struct list_head dt_maps;
struct kref users;
};
- pinctrl为具体驱动程序使用pinctrl接口,将pinctrl和对应的设备相关联
/* List of pin controller handles (struct pinctrl) */
static LIST_HEAD(pinctrl_list);
- pinctrl_list保存系统中所有的pinctrl句柄
struct pinctrl_map {
const char *dev_name;
const char *name;
enum pinctrl_map_type type;
const char *ctrl_dev_name;
union {
struct pinctrl_map_mux mux;
struct pinctrl_map_configs configs;
} data;
};
- name为设备树中pinctrl的statename
- dev_name为与pinctrl相关联的设备的名称
- ctrl_dev_name为pinctldev设备名称
二、设备和驱动匹配时默认调用pinctrl接口
- 在设备与驱动匹配的过程中会调用到__device_attach_driver或者__driver_attach函数，这二者都会去调用driver_probe_device函数
int driver_probe_device(struct device_driver *drv, struct device *dev)
{
......
pm_runtime_barrier(dev);
ret = really_probe(dev, drv);
pm_request_idle(dev);
.....
}
- 该函数会继续调用really_probe进行设备与驱动的匹配工作
static int really_probe(struct device *dev, struct device_driver *drv) {
......
/* If using pinctrl, bind pins now before probing */
ret = pinctrl_bind_pins(dev);
if (ret)
goto pinctrl_bind_failed;
......
}
- really_probe会调用pinctrl_bind_pins进行Pinctrl的配置
/**
* pinctrl_bind_pins() - called by the device core before probe
* @dev: the device that is just about to probe
*/
int pinctrl_bind_pins(struct device *dev)
{
int ret;
if (dev->of_node_reused)
return 0;
dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
if (!dev->pins)
return -ENOMEM;
dev->pins->p = devm_pinctrl_get(dev); // 接口1
if (IS_ERR(dev->pins->p)) {
dev_dbg(dev, "no pinctrl handle\n");
ret = PTR_ERR(dev->pins->p);
goto cleanup_alloc;
}
dev->pins->default_state = pinctrl_lookup_state(dev->pins->p, // 接口2
PINCTRL_STATE_DEFAULT);
if (IS_ERR(dev->pins->default_state)) {
dev_dbg(dev, "no default pinctrl state\n");
ret = 0;
goto cleanup_get;
}
dev->pins->init_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_INIT);
if (IS_ERR(dev->pins->init_state)) {
/* Not supplying this state is perfectly legal */
dev_dbg(dev, "no init pinctrl state\n");
ret = pinctrl_select_state(dev->pins->p,
dev->pins->default_state);
} else {
ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state); // 接口3
}
if (ret) {
dev_dbg(dev, "failed to activate initial pinctrl state\n");
goto cleanup_get;
}
#ifdef CONFIG_PM
/*
* If power management is enabled, we also look for the optional
* sleep and idle pin states, with semantics as defined in
* <linux/pinctrl/pinctrl-state.h>
*/
dev->pins->sleep_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_SLEEP);
if (IS_ERR(dev->pins->sleep_state))
/* Not supplying this state is perfectly legal */
dev_dbg(dev, "no sleep pinctrl state\n");
dev->pins->idle_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_IDLE);
if (IS_ERR(dev->pins->idle_state))
/* Not supplying this state is perfectly legal */
dev_dbg(dev, "no idle pinctrl state\n");
#endif
return 0;
/*
* If no pinctrl handle or default state was found for this device,
* let's explicitly free the pin container in the device, there is
* no point in keeping it around.
*/
cleanup_get:
devm_pinctrl_put(dev->pins->p);
cleanup_alloc:
devm_kfree(dev, dev->pins);
dev->pins = NULL;
/* Return deferrals */
if (ret == -EPROBE_DEFER)
return ret;
/* Return serious errors */
if (ret == -EINVAL)
return ret;
/* We ignore errors like -ENOENT meaning no pinctrl state */
return 0;
}
- 调用devm_pinctrl_get获取pinctrl句柄,devm_pinctrl_get实际调用pinctrl_get
- 调用pinctrl_lookup_state查询所需的pinctrl_state
- 调用pinctrl_select_state设置对应管脚状态
- 首先获取default_state、init_state，并先优配置管脚为init_state，如果init_state不存在则配置为default_state
- 如果有电源管理配置，则获取sleep_state、idle_state
三、pinctrl的接口分析
struct pinctrl *pinctrl_get(struct device *dev)
{
struct pinctrl *p;
if (WARN_ON(!dev))
return ERR_PTR(-EINVAL);
/*
* See if somebody else (such as the device core) has already
* obtained a handle to the pinctrl for this device. In that case,
* return another pointer to it.
*/
p = find_pinctrl(dev);
if (p != NULL) {
dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n");
kref_get(&p->users);
return p;
}
return create_pinctrl(dev);
}
- 首先调用find_pinctrl函数查找pinctrl句柄，如果找到就直接返回
- 如果find_pinctrl没有找到pinctrl句柄, 则创建create_pinctrl
static struct pinctrl *find_pinctrl(struct device *dev)
{
struct pinctrl *p;
mutex_lock(&pinctrl_list_mutex);
list_for_each_entry(p, &pinctrl_list, node)
if (p->dev == dev) {
mutex_unlock(&pinctrl_list_mutex);
return p;
}
mutex_unlock(&pinctrl_list_mutex);
return NULL;
}
- 遍历pinctrl_list查找与dev相匹配的设备pinctrl句柄
static struct pinctrl *create_pinctrl(struct device *dev)
{
struct pinctrl *p;
const char *devname;
struct pinctrl_maps *maps_node;
int i;
struct pinctrl_map const *map;
int ret;
/*
* 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(*p), GFP_KERNEL);
if (p == NULL) {
dev_err(dev, "failed to alloc struct pinctrl\n");
return ERR_PTR(-ENOMEM);
}
p->dev = dev;
INIT_LIST_HEAD(&p->states);
INIT_LIST_HEAD(&p->dt_maps);
ret = pinctrl_dt_to_map(p);
if (ret < 0) {
kfree(p);
return ERR_PTR(ret);
}
devname = dev_name(dev);
mutex_lock(&pinctrl_maps_mutex);
/* Iterate over the pin control maps to locate the right ones */
for_each_maps(maps_node, i, map) {
/* Map must be for this device */
if (strcmp(map->dev_name, devname))
continue;
ret = add_setting(p, map);
/*
* At this point the adding of a setting may:
*
* - Defer, if the pinctrl device is not yet available
* - Fail, if the pinctrl device is not yet available,
* AND the setting is a hog. We cannot defer that, since
* the hog will kick in immediately after the device
* is registered.
*
* If the error returned was not -EPROBE_DEFER then we
* accumulate the errors to see if we end up with
* an -EPROBE_DEFER later, as that is the worst case.
*/
if (ret == -EPROBE_DEFER) {
pinctrl_free(p, false);
mutex_unlock(&pinctrl_maps_mutex);
return ERR_PTR(ret);
}
}
mutex_unlock(&pinctrl_maps_mutex);
if (ret < 0) {
/* If some other error than deferral occured, return here */
pinctrl_free(p, false);
return ERR_PTR(ret);
}
kref_init(&p->users);
/* Add the pinctrl handle to the global list */
mutex_lock(&pinctrl_list_mutex);
list_add_tail(&p->node, &pinctrl_list);
mutex_unlock(&pinctrl_list_mutex);
return p;
}
- 动态创建pinctrl并进行相应初始化工作
- 调用pinctrl_dt_to_map将pinctrl设备树解析为pinctrl_map，并注册到pinctrl_maps
- 查找pinctrl_maps，调用add_setting将相应的map添加到pinctrl
- 将pinctrl添加到pinctrl_list以便于后面查找
int pinctrl_dt_to_map(struct pinctrl *p)
{
......
/* For each defined state ID */
for (state = 0; ; state++) {
......
/* 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;
}
.......
}
......
}
- 首先找到对应的设备树结点np_config
- 然后调用dt_to_map_one_config去解析设备树
static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
......
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);
}
- 调用pctldev->desc->pctlops的dt_node_to_map函数去解析设备树(与具体的pinctrl控制器有关)
- 调用dt_remember_or_free_map去注册map
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);
}
- 动态分配dt_map，然后注册到pinctrl上
- 调用pinctrl_register_map创建pinctrl_maps，并将mpinctrl_maps注册到pinctrl_maps链表上，至此pinctrl_dt_to_map的工作基本完成，继续回到create_pinctrl
static int add_setting(struct pinctrl *p, struct pinctrl_map const *map)
{
struct pinctrl_state *state;
struct pinctrl_setting *setting;
int ret;
state = find_state(p, map->name);
if (!state)
state = create_state(p, map->name);
if (IS_ERR(state))
return PTR_ERR(state);
if (map->type == PIN_MAP_TYPE_DUMMY_STATE)
return 0;
setting = kzalloc(sizeof(*setting), GFP_KERNEL);
if (setting == NULL) {
dev_err(p->dev,
"failed to alloc struct pinctrl_setting\n");
return -ENOMEM;
}
setting->type = map->type;
setting->pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
if (setting->pctldev == NULL) {
kfree(setting);
/* Do not defer probing of hogs (circular loop) */
if (!strcmp(map->ctrl_dev_name, map->dev_name))
return -ENODEV;
/*
* OK let us guess that the driver is not there yet, and
* let's defer obtaining this pinctrl handle to later...
*/
dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe",
map->ctrl_dev_name);
return -EPROBE_DEFER;
}
setting->dev_name = map->dev_name;
switch (map->type) {
case PIN_MAP_TYPE_MUX_GROUP:
ret = pinmux_map_to_setting(map, setting);
break;
case PIN_MAP_TYPE_CONFIGS_PIN:
case PIN_MAP_TYPE_CONFIGS_GROUP:
ret = pinconf_map_to_setting(map, setting);
break;
default:
ret = -EINVAL;
break;
}
if (ret < 0) {
kfree(setting);
return ret;
}
list_add_tail(&setting->node, &state->settings);
return 0;
}
- 根据pinctrl和map名称查找state，如果没有找到就创建
- 动态创建setting并初始化，然后添加到state的settings链表上
struct pinctrl_state *pinctrl_lookup_state(struct pinctrl *p,
const char *name)
{
struct pinctrl_state *state;
state = find_state(p, name);
if (!state) {
if (pinctrl_dummy_state) {
/* create dummy state */
dev_dbg(p->dev, "using pinctrl dummy state (%s)\n",
name);
state = create_state(p, name);
} else
state = ERR_PTR(-ENODEV);
}
return state;
}
- 根据名称查找pinctrl里的state，返回pinctrl_state
int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)
{
struct pinctrl_setting *setting, *setting2;
struct pinctrl_state *old_state = p->state;
int ret;
if (p->state == state)
return 0;
if (p->state) {
/*
* For each pinmux setting in the old state, forget SW's record
* of mux owner for that pingroup. Any pingroups which are
* still owned by the new state will be re-acquired by the call
* to pinmux_enable_setting() in the loop below.
*/
list_for_each_entry(setting, &p->state->settings, node) {
if (setting->type != PIN_MAP_TYPE_MUX_GROUP)
continue;
pinmux_disable_setting(setting);
}
}
p->state = NULL;
/* Apply all the settings for the new state */
list_for_each_entry(setting, &state->settings, node) {
switch (setting->type) {
case PIN_MAP_TYPE_MUX_GROUP:
ret = pinmux_enable_setting(setting);
break;
case PIN_MAP_TYPE_CONFIGS_PIN:
case PIN_MAP_TYPE_CONFIGS_GROUP:
ret = pinconf_apply_setting(setting);
break;
default:
ret = -EINVAL;
break;
}
if (ret < 0) {
goto unapply_new_state;
}
}
p->state = state;
......
}
- 调用pinmux_enable_setting和pinconf_apply_setting应用相应settings
