网站不备案可以上线吗,如何开展网站推广,情感营销经典案例,青岛logo设计一、背景
cpu的gpio引脚可以复用成多个功能#xff0c;如可以配置成I2C或者普通GPIO模式。配置方式一般是通过写引脚复用的配置寄存器#xff0c;但是不同芯片厂商配置寄存器格式内容各不相同#xff0c;设置引脚复用无法做到通用且自由的配置#xff0c;只能在启动初始化…一、背景
cpu的gpio引脚可以复用成多个功能如可以配置成I2C或者普通GPIO模式。配置方式一般是通过写引脚复用的配置寄存器但是不同芯片厂商配置寄存器格式内容各不相同设置引脚复用无法做到通用且自由的配置只能在启动初始化时候在soc驱动初始化时对每个引脚配置好。 linux 3.0之后内核中抽象出了pinctrl子系统每个soc注册设置引脚复用的方法以及将soc的每个引脚可选的复用功能。
二、pinctrl实现
2.1 API
# 用于soc向pinctrl系统中注册设置引脚复用方法以及设置引脚复用状态
# driver_data用于soc驱动私有数据一般用来保存pin 引脚的可选复用功能列表。
struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,struct device *dev, void *driver_data)# 设置引脚复用状态用来设置引脚复用状态
int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)# 用于具体设备驱动(i2c等)关联pinctrl节点以及设置默认复用模式设备树解析时调用
int pinctrl_bind_pins(struct device *dev)2.2 数据结构
数据结构关系图 这里主要有几个对象
pin_group 和function : 引脚复用一般是多个引脚组成一个group一起设置复用状态的。多个引脚复用为某个功能成为function。
pin_conf 设置引脚的上下拉电阻等电气参数pin_mux设置引脚复用
pinctrl_desc
核心数据结构是pinctrl_descpinctrl的全局描述。
struct pinctrl_desc {const char *name;/*系统种有多少个pinctrl*/const struct pinctrl_pin_desc *pins;unsigned int npins;/*引脚控制的操作集不同芯片方案不同*/const struct pinctrl_ops *pctlops;const struct pinmux_ops *pmxops;const struct pinconf_ops *confops;struct module *owner;
};pinctrl_pin_desc
描述系统中的所有引脚drv_data保存驱动私有数据。
struct pinctrl_pin_desc {unsigned number;const char *name;void *drv_data;
};pinctrl_ops
回调函数获取pin group的操作以及解析dts。
struct pinctrl_ops {/*获取系统中有多少个pin groups*/int (*get_groups_count) (struct pinctrl_dev *pctldev);/*获取指定group由索引selector指定的名称由select确认*/const char *(*get_group_name) (struct pinctrl_dev *pctldev,unsigned selector);/*获取指定group的所用pin信息*/int (*get_group_pins) (struct pinctrl_dev *pctldev,unsigned selector,const unsigned **pins,unsigned *num_pins);void (*pin_dbg_show) (struct pinctrl_dev *pctldev, struct seq_file *s,unsigned offset);/*将对应驱动转换成pin map*/int (*dt_node_to_map) (struct pinctrl_dev *pctldev,struct device_node *np_config,struct pinctrl_map **map, unsigned *num_maps);void (*dt_free_map) (struct pinctrl_dev *pctldev,struct pinctrl_map *map, unsigned num_maps);
};pinconf_ops
配置管脚状态pinctrl也提供管脚状态如上下拉、开漏等的接口。
struct pinconf_ops {
#ifdef CONFIG_GENERIC_PINCONFbool is_generic;
#endif/*获取pin脚的当前状态*/int (*pin_config_get) (struct pinctrl_dev *pctldev,unsigned pin,unsigned long *config);/*设置pin脚状态*/int (*pin_config_set) (struct pinctrl_dev *pctldev,unsigned pin,unsigned long *configs,unsigned num_configs);/*获取或者设置指定pin group的配置项*/int (*pin_config_group_get) (struct pinctrl_dev *pctldev,unsigned selector,unsigned long *config);int (*pin_config_group_set) (struct pinctrl_dev *pctldev,unsigned selector,unsigned long *configs,unsigned num_configs);int (*pin_config_dbg_parse_modify) (struct pinctrl_dev *pctldev,const char *arg,unsigned long *config);void (*pin_config_dbg_show) (struct pinctrl_dev *pctldev,struct seq_file *s,unsigned offset);void (*pin_config_group_dbg_show) (struct pinctrl_dev *pctldev,struct seq_file *s,unsigned selector);void (*pin_config_config_dbg_show) (struct pinctrl_dev *pctldev,struct seq_file *s,unsigned long config);
};pinmux_ops
设置或获取引脚复用情况对应硬件是iomux。设置某个pin为某个function通过set_mux设置function selecter。 一个group设置复用状态。
struct pinmux_ops {int (*request) (struct pinctrl_dev *pctldev, unsigned offset);int (*free) (struct pinctrl_dev *pctldev, unsigned offset);int (*get_functions_count) (struct pinctrl_dev *pctldev);const char *(*get_function_name) (struct pinctrl_dev *pctldev,unsigned selector);int (*get_function_groups) (struct pinctrl_dev *pctldev,unsigned selector,const char * const **groups,unsigned *num_groups);/*将指定的pin groupgroup_selector设置为指定的functionfunc_selector*/int (*set_mux) (struct pinctrl_dev *pctldev, unsigned func_selector,unsigned group_selector);int (*gpio_request_enable) (struct pinctrl_dev *pctldev,struct pinctrl_gpio_range *range,unsigned offset);void (*gpio_disable_free) (struct pinctrl_dev *pctldev,struct pinctrl_gpio_range *range,unsigned offset);int (*gpio_set_direction) (struct pinctrl_dev *pctldev,struct pinctrl_gpio_range *range,unsigned offset,bool input);bool strict;
};pinctrl_map
pinctrl_map 某个gpio具体的引脚配置和复用状态由dts中定义dt_node_to_map函数解析和具体设备驱动关联。
struct pinctrl_map {//device的名称const char *dev_name;//pin state的名称const char *name;//该map的类型enum pinctrl_map_type type;//pin controller device的名字const char *ctrl_dev_name;union {struct pinctrl_map_mux mux;struct pinctrl_map_configs configs;} data;
};enum pinctrl_map_type {PIN_MAP_TYPE_INVALID,//不需要任何配置仅仅为了表示state的存在PIN_MAP_TYPE_DUMMY_STATE,//配置管脚复用PIN_MAP_TYPE_MUX_GROUP,//配置pinPIN_MAP_TYPE_CONFIGS_PIN,//配置pin groupPIN_MAP_TYPE_CONFIGS_GROUP,
};struct pinctrl_map_mux {//group的名字const char *group;//function的名字const char *function;
};struct pinctrl_map_configs {//该pin或者pin group的名字const char *group_or_pin;//configuration数组unsigned long *configs;//配置项的个数unsigned num_configs;
};三、实现流程
linux6.1.11为例pinctrl系统融入内核设备树解析以及内核设备驱动模型中支持。以zynq为例从dts配置解析入手了解pinctrl的工作原理。dts中主要关注
1pinctrl 子系统描述系统多少引脚每个引脚有多少复用情况。
2I2C、GPIO、SPI等driver默认配置的pinctrl复用设置
《zynq-7000.dtsi》中如列出i2C和uart的复用配置其中只是选择了i2c0_10_grp这个pin_group并且配置为i2c0的复用功能具体引脚的引脚号等信息是在代码中定义的。
mux 和 conf的作用
pinctrl0: pinctrl700 {compatible xlnx,pinctrl-zynq;reg 0x700 0x200;syscon slcr;/*设置引脚的复用状态*/pinctrl_i2c0_default: i2c0-default {mux {/*pin_group*/groups i2c0_10_grp;/*复用功能为i2c0*/function i2c0;};conf {groups i2c0_10_grp;bias-pull-up; #上拉电阻slew-rate 0; #引脚转换速率io-standard 1;};};pinctrl_uart1_default: uart1-default {mux {groups uart1_10_grp;function uart1;};conf {groups uart1_10_grp;slew-rate 0;io-standard 1;};conf-rx {pins MIO49;bias-high-impedance;};conf-tx {pins MIO48;bias-disable;};};}其他驱动如何关联pinctrl以及配置默认引脚复用
对应驱动中的dts新增如下两个属性在设备驱动device关联driver时会解析如下字段关联pinctrl驱动并设置引脚复用状态这里是选择pinctrl_i2c0_default。
i2c0 {pinctrl-names default;pinctrl-0 pinctrl_i2c0_default;3.1 驱动注册
《linux-6.1.11\drivers\pinctrl\pinctrl-zynq.c》
构造一个pinctrl_desc结构然后注册到pinctrl系统中。
static struct pinctrl_desc zynq_desc {.name zynq_pinctrl,.pins zynq_pins,.npins ARRAY_SIZE(zynq_pins),.pctlops zynq_pctrl_ops,.pmxops zynq_pinmux_ops,.confops zynq_pinconf_ops,.num_custom_params ARRAY_SIZE(zynq_dt_params),.custom_params zynq_dt_params,
#ifdef CONFIG_DEBUG_FS.custom_conf_items zynq_conf_items,
#endif.owner THIS_MODULE,
};static int zynq_pinctrl_probe(struct platform_device *pdev){pctrl-pctrl devm_pinctrl_register(pdev-dev, zynq_desc, pctrl);
}pin引脚定义
/*定义系统中引脚*/
static const struct pinctrl_pin_desc zynq_pins[] {PINCTRL_PIN(0, MIO0),PINCTRL_PIN(1, MIO1),...
}/*引脚可选复用功能*/
enum zynq_pinmux_functions {ZYNQ_PMUX_can0,ZYNQ_PMUX_can1,ZYNQ_PMUX_ethernet0,ZYNQ_PMUX_ethernet1,
}/* pin groups 组每个引脚功能对应的pin脚定义*/
static const unsigned int ethernet0_0_pins[] {16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27};
static const unsigned int ethernet1_0_pins[] {28, 29, 30, 31, 32, 33, 34, 35,36, 37, 38, 39};
static const unsigned int mdio0_0_pins[] {52, 53};
static const unsigned int mdio1_0_pins[] {52, 53};/*zynq维护的私有数据结构pin_group组信息关联上述pin脚*/
static const struct zynq_pctrl_group zynq_pctrl_groups[] {DEFINE_ZYNQ_PINCTRL_GRP(ethernet0_0),DEFINE_ZYNQ_PINCTRL_GRP(ethernet1_0),DEFINE_ZYNQ_PINCTRL_GRP(mdio0_0),DEFINE_ZYNQ_PINCTRL_GRP(mdio1_0),DEFINE_ZYNQ_PINCTRL_GRP(qspi0_0),DEFINE_ZYNQ_PINCTRL_GRP(qspi1_0),DEFINE_ZYNQ_PINCTRL_GRP(qspi_fbclk),DEFINE_ZYNQ_PINCTRL_GRP(qspi_cs1),DEFINE_ZYNQ_PINCTRL_GRP(spi0_0),
}对应的ops实现这里不展开具体写寄存器信息。
3.2 具体驱动关联pinctrl
具体i2c、spi等驱动初始化时如何设置引脚复用情况 dts中定义i2c选择pinctrl_i2c0_default的引脚复用。 pinctrl-names用于表示pinctrl_state有init、defaultinit是在驱动初始化的状态default是默认状态。 pinctrl-0 选择复用情况这两个属性是pinctrl的标准属性设备树解析框架中实现在设备驱动匹配时关联。
i2c0 {pinctrl-names default;pinctrl-0 pinctrl_i2c0_default;时机设备驱动匹配时关联以及设置默认复用状态。
关键函数pinctrl_bind_pins
《linux-6.1.11\drivers\base\dd.c》
__driver_probe_device - really_probe - pinctrl_bind_pins解析dts关联pinctrl_map
调用pinconf_generic_dt_node_to_map_all解析dts。关联pinctrl_i2c0_default的pinctrl_map。
pinctrl_bind_pins - create_pinctrl - pinctrl_dt_to_map - pinconf_generic_dt_node_to_map_all 设置引脚复用
pinctrl_bind_pins - pinctrl_select_state (选择default state) - pinctrl_commit_state- pinmux_disable_setting (禁用旧的复用)- pinmux_enable_setting (设置新复用)- pinconf_apply_setting (设置引脚状态)/*** 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);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,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);}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);
#endifreturn 0;/** If no pinctrl handle or default state was found for this device,* lets 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;
}
