pinctrl框架

pinctrl框架是linux系统为统一各SOC厂家pin管理，目的是为了减少SOC厂家系统移植工作量。

通常通过设备树初始化pinctrl，并提供调用io接口，以下为全志A64平台的实例：

在drivers/pinctrl/sunxi/pinctrl-sun50iw1p1.c:

 static const struct sunxi_desc_pin sun50iw1p1_pins[] = {
     SUNXI_PIN(SUNXI_PINCTRL_PIN(B, ),
           SUNXI_FUNCTION(0x0, "gpio_in"),
           SUNXI_FUNCTION(0x1, "gpio_out"),
           SUNXI_FUNCTION(0x2, "uart2"),        /*TX*/
           SUNXI_FUNCTION(0x3, "vdevice"),    /*vdevice for test */
           SUNXI_FUNCTION(0x4, "jtag0"),        /*MS0*/
           SUNXI_FUNCTION(0x7, "io_disabled"),
           SUNXI_FUNCTION_IRQ_BANK(0x6, , )),    /*PB_EINT0 */
     SUNXI_PIN(SUNXI_PINCTRL_PIN(B, ),
           SUNXI_FUNCTION(0x0, "gpio_in"),
           SUNXI_FUNCTION(0x1, "gpio_out"),
           SUNXI_FUNCTION(0x2, "uart2"),        /*RX*/
           SUNXI_FUNCTION(0x3, "vdevice"),    /*vdevice for test */
           SUNXI_FUNCTION(0x4, "jtag0"),        /*CK0*/
           SUNXI_FUNCTION(0x5, "sim0"),        /*PWREN*/
           SUNXI_FUNCTION(0x7, "io_disabled"),
           SUNXI_FUNCTION_IRQ_BANK(0x6, , )),    /*PB_EINT1 */
     ......
     ......
     ......
 };

 static const struct sunxi_pinctrl_desc sun50iw1p1_pinctrl_data = {
     .pins = sun50iw1p1_pins,
     .npins = ARRAY_SIZE(sun50iw1p1_pins),
     .irq_banks = ,
 };

 static int sun50iw1p1_pinctrl_probe(struct platform_device *pdev)
 {
     pr_warn("[%s][%d]\n", __func__, __LINE__);
     return sunxi_pinctrl_init(pdev,
                   &sun50iw1p1_pinctrl_data);
 }

 static struct of_device_id sun50iw1p1_pinctrl_match[] = {
     { .compatible = "allwinner,sun50i-pinctrl", },
     {}
 };
 MODULE_DEVICE_TABLE(of, sun50iw1p1_pinctrl_match);

 static struct platform_driver sun50iw1p1_pinctrl_driver = {
     .probe    = sun50iw1p1_pinctrl_probe,
     .driver    = {
         .name        = "sun50i-pinctrl",
         .owner        = THIS_MODULE,
         .of_match_table    = sun50iw1p1_pinctrl_match,
     },
 };
 static int __init sun50iw1p1_pio_init(void)
 {
     int ret;
     ret = platform_driver_register(&sun50iw1p1_pinctrl_driver);
     if (IS_ERR_VALUE(ret)) {
         pr_debug("register sun50i pio controller failed\n");
         return -EINVAL;
     }
     return ;
 }
 postcore_initcall(sun50iw1p1_pio_init);

start_kernel----rest_init----kernel_init----kernel_init_freeable----do_basic_setup----do_initcalls调用postcore_initcall。

注册平台驱动，匹配设备最后调用sunxi_pinctrl_init(pdev, &sun50iw1p1_pinctrl_data);

sun50iw1p1_pins为全志平台的PIN IO和IRQ的定义，里面定义引脚名字name，复用功能muxval，中断号irqnum。

忽略部分代码的drivers/pinctrl/sunxi/pinctrl-sunxi.c:

 int sunxi_pinctrl_init(struct platform_device *pdev,
                const struct sunxi_pinctrl_desc *desc)
 {
     struct device_node *node = pdev->dev.of_node;
     struct pinctrl_desc *pctrl_desc;
     struct pinctrl_pin_desc *pins;
     struct sunxi_pinctrl *pctl;
     struct resource *res;
     int i, ret, last_pin;
     struct clk *clk;
     pctl = devm_kzalloc(&pdev->dev, sizeof(*pctl), GFP_KERNEL);

     platform_set_drvdata(pdev, pctl);

     res = platform_get_resource(pdev, IORESOURCE_MEM, );
     pctl->membase = devm_ioremap_resource(&pdev->dev, res);    //返回设备的MEM资源的虚拟地址

     pctl->dev = &pdev->dev;
     pctl->desc = desc;

     pctl->irq_array = devm_kcalloc(&pdev->dev, IRQ_PER_BANK * pctl->desc->irq_banks,
                        sizeof(*pctl->irq_array), GFP_KERNEL);

     //把sunxi_pinctrl_desc的内容全部映射到sunxi_pinctrl的成员(sunxi_pinctrl_group、irq_array和sunxi_pinctrl_function)
     ret = sunxi_pinctrl_build_state(pdev);

     pins = devm_kzalloc(&pdev->dev, pctl->desc->npins * sizeof(*pins),  GFP_KERNEL);

     for (i = ; i < pctl->desc->npins; i++)
         pins[i] = pctl->desc->pins[i].pin;

     //注册pctldev，这里把平台硬件相关函数向上映射到pinctrl子系统
     pctrl_desc = devm_kzalloc(&pdev->dev, sizeof(*pctrl_desc), GFP_KERNEL);

     //confops、pctlops和pmxops都是直接和硬件相关，新设备配置PIN需要用到
     pctrl_desc->name = dev_name(&pdev->dev);
     pctrl_desc->owner = THIS_MODULE;
     pctrl_desc->pins = pins;
     pctrl_desc->npins = pctl->desc->npins;
     pctrl_desc->confops = &sunxi_pconf_ops;　　//pin config operations vtable
     pctrl_desc->pctlops = &sunxi_pctrl_ops;            //pin control operation vtable
     pctrl_desc->pmxops =  &sunxi_pmx_ops;         //pinmux operations vtable

     //把描述表的name和number加入radix_tree，分配pinctrl_dev并把加入双链表，这里没有创建新的pinctrl设备，也没有state
     pctl->pctl_dev = pinctrl_register(pctrl_desc, &pdev->dev, pctl);

     //注册gpio子系统，把平台硬件相关函数向上映射到gpio子系统
     pctl->chip = devm_kzalloc(&pdev->dev, sizeof(*pctl->chip), GFP_KERNEL);

     last_pin = pctl->desc->pins[pctl->desc->npins - ].pin.number;
     pctl->chip->owner = THIS_MODULE;
     pctl->chip->request = sunxi_pinctrl_gpio_request,
     pctl->chip->free = sunxi_pinctrl_gpio_free,
     pctl->chip->direction_input = sunxi_pinctrl_gpio_direction_input,
     pctl->chip->direction_output = sunxi_pinctrl_gpio_direction_output,
     pctl->chip->get = sunxi_pinctrl_gpio_get,
     pctl->chip->set = sunxi_pinctrl_gpio_set,
     pctl->chip->set_debounce = sunxi_pinctrl_gpio_set_debounce,
     pctl->chip->of_xlate = sunxi_pinctrl_gpio_of_xlate,
     pctl->chip->to_irq = sunxi_pinctrl_gpio_to_irq,
     pctl->chip->of_gpio_n_cells = ,
     pctl->chip->can_sleep = false,
     pctl->chip->ngpio = round_up(last_pin + , PINS_PER_BANK) - pctl->desc->pin_base;
     pctl->chip->label = dev_name(&pdev->dev);
     pctl->chip->dev = &pdev->dev;
     pctl->chip->base = pctl->desc->pin_base;

     ret = gpiochip_add(pctl->chip);    //把gpio_chip(A64有两个chip)加入双链表

     for (i = ; i < pctl->desc->npins; i++) {
         const struct sunxi_desc_pin *pin = pctl->desc->pins + i;
         //注册gpio_ranges，并加入双链表
         ret = gpiochip_add_pin_range(pctl->chip, dev_name(&pdev->dev),
                          pin->pin.number - pctl->desc->pin_base,
                          pin->pin.number, );
     }

     clk = devm_clk_get(&pdev->dev, NULL);

     ret = clk_prepare_enable(clk);
     if (ret)
         goto gpiochip_error;

     pctl->irq = devm_kcalloc(&pdev->dev,
                  pctl->desc->irq_banks,
                  sizeof(*pctl->irq),
                  GFP_KERNEL);

     for (i = ; i < pctl->desc->irq_banks; i++) {
         pctl->irq[i] = platform_get_irq(pdev, i);        //获取中断资源
     }

     pctl->domain = irq_domain_add_linear(node, pctl->desc->irq_banks * IRQ_PER_BANK,
                          &irq_domain_simple_ops, NULL);    //把pinctrl加入线性中断域，pin中断都域中搜索

     for (i = ; i < (pctl->desc->irq_banks * IRQ_PER_BANK); i++) {
         int irqno = irq_create_mapping(pctl->domain, i);    //获取线性中断域的irq号

         irq_set_chip_and_handler(irqno, &sunxi_pinctrl_edge_irq_chip,
                      handle_edge_irq); //sunxi_pinctrl_edge_irq_chip为全志底层irq_chip操作
         irq_set_chip_data(irqno, pctl);
     };

     for (i = ; i < pctl->desc->irq_banks; i++) {
         /* Mask and clear all IRQs before registering a handler */
         writel(, pctl->membase + sunxi_irq_ctrl_reg_from_bank(i));
         writel(0xffffffff, pctl->membase + sunxi_irq_status_reg_from_bank(i));
         if(pctl->desc->pin_base >= PL_BASE){
             ret = devm_request_irq(&pdev->dev, pctl->irq[i], sunxi_pinctrl_irq_handler,
                                IRQF_SHARED | IRQF_NO_SUSPEND, "PIN_GRP", pctl);
             //同一个bank的gpio中断均共享一个中断，在sunxi_pinctrl_irq_handler通过gpio的中断号
             //启动对应generic_handle_irq
         }else{
             ret = devm_request_irq(&pdev->dev, pctl->irq[i], sunxi_pinctrl_irq_handler,
                                IRQF_SHARED, "PIN_GRP", pctl); //同上
         }
     }

     return ;
 }

在设备树实例（一）中的：

      soc@01c00000 {
          compatible = "simple-bus";
          #address-cells = <0x2>;
          #size-cells = <0x2>;
          ranges;
          device_type = "soc";

          pinctrl@01c20800 {
              compatible = "allwinner,sun50i-pinctrl";
              reg = <0x0 0x1c20800 0x0 0x400>;
              interrupts = <0x0 0xb 0x4 0x0 0x11 0x4 0x0 0x15 0x4>;
              device_type = "pio";
              clocks = <0xa>;
              gpio-controller;
              interrupt-controller;
              #interrupt-cells = <0x2>;
              #size-cells = <0x0>;
              #gpio-cells = <0x6>;
              linux,phandle = <0x30>;
              phandle = <0x30>;

              uart0@ {
                  allwinner,pins = "PB8", "PB9";
                  allwinner,pname = "uart0_tx", "uart0_rx";
                  allwinner,function = "uart0";
                  allwinner,muxsel = <0x4>;
                  allwinner,drive = <0x1>;
                  allwinner,pull = <0x1>;
                  linux,phandle = <0x19>;
                  phandle = <0x19>;
              };

              uart0@ {
                  allwinner,pins = "PB8", "PB9";
                  allwinner,function = "io_disabled";
                  allwinner,muxsel = <0x7>;
                  allwinner,drive = <0x1>;
                  allwinner,pull = <0x1>;
                  linux,phandle = <0x1a>;
                  phandle = <0x1a>;
              };

              ......
              ......
              ......
          };

          uart@01c28000 {
              compatible = "allwinner,sun50i-uart";
              device_type = "uart0";
              reg = <0x0 0x1c28000 0x0 0x400>;
              interrupts = <0x0 0x0 0x4>;
              clocks = <0x18>;
              pinctrl-names = "default", "sleep";
              pinctrl- = <0x19>;
              pinctrl- = <0x1a>;
              uart0_port = <0x0>;
              uart0_type = <0x2>;
              status = "disabled";
          };

pinctrl-names = "default", "sleep";的两种状态的phandle对应于pinctrl-0(uart0@0)和pinctrl-1(uart0@1)，uart0@0里面的配置是全志硬件平台相关，跟confops、pctlops和pmxops相关。

如何开启设备树对应的pin配置？

一般在driver程序里面调用devm_pinctrl_get_select_default就可以。

定义在linux3-10/include/pintrl/consumer.h：

 static inline struct pinctrl * __must_check devm_pinctrl_get_select(
                     struct device *dev, const char *name)
 {
     struct pinctrl *p;
     struct pinctrl_state *s;
     int ret;

     //通过device获取phandle，若是新设备则会调用创建head_list，找到pinctrl父设备sun50i-pinctrl ，解析设备树，
     //创建states，获取硬件相关配置，最后add devices。
     p = devm_pinctrl_get(dev);
     if (IS_ERR(p))
         return p;

     s = pinctrl_lookup_state(p, name);
     if (IS_ERR(s)) {
         devm_pinctrl_put(p);
         return ERR_CAST(s);
     }
     //设置state(默认是DEFAULT)从设备树对应的配置
     ret = pinctrl_select_state(p, s);
     if (ret < ) {
         devm_pinctrl_put(p);
         return ERR_PTR(ret);
     }

     return p;
 }

调用IO口或者中断可以参考linux-3.10/drivers/pinctrl/sunxi/pinctrl-sunxi-test.c

 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/sys_config.h>
 #include <linux/string.h>

 static struct of_device_id sunxi_pinctrl_test_match[] = {
     { .compatible = "allwinner,sun50i-vdevice"},
 };    //这里要在dts文件建立compatible = "allwinner,sun50i-vdevice"的node才能匹配driver

 static irqreturn_t test_sunxi_pinctrl_irq_handler(int irq, void *dev_id)
 {
     pr_warn("[%s] handler for test pinctrl eint api.\n", __func__);
     disable_irq_nosync(irq);
     return IRQ_HANDLED;

 }

 static int sunxi_pinctrl_test_probe(struct platform_device *pdev)
 {
     struct gpio_config config;
     unsigned int ret;
     struct device_node *node;

     int    req_irq_status;
     int    req_status;
     int    virq;

     node=of_find_node_by_type(NULL, "vdevice");    //通过属性device_type = "vdevice"找到设备树节点
     if(!node){
         printk("find node\n");
     }
     ret = of_get_named_gpio_flags(node, "test-gpios", , (enum of_gpio_flags *)&config);
     //找到设备树属性test-gpios，解析GPIO配置，这步是重点(不同硬件平台不一定相同)
     if (!gpio_is_valid(ret)) {
         return -EINVAL;
     }
     printk("config: gpio=%d mul=%d drive=%d pull=%d data=%d\n"
                 , config.gpio
                 , config.mul_sel
                 , config.drv_level
                 , config.pull
                 , config.data);
     req_status = gpio_request(config.gpio, NULL);
     if ( != req_status)
         return -EINVAL;
     virq = gpio_to_irq(config.gpio);
     if (IS_ERR_VALUE(virq)) {
         pr_warn("gpio[%d]get virq[%d] failed!\n", config.gpio, virq);
         return -EINVAL;
     }
     req_irq_status = devm_request_irq(&pdev->dev, virq,
                     test_sunxi_pinctrl_irq_handler,
                     IRQF_TRIGGER_LOW, "GPIO_EINT", NULL);
     if (IS_ERR_VALUE(req_irq_status)) {
         pr_warn("request irq failed !\n");
         return -EINVAL;
     }
     return ;
 }

 static struct platform_driver sunxi_pinctrl_test_driver = {
     .probe = sunxi_pinctrl_test_probe,
     .driver = {
         .name = "vdevice",
         .owner = THIS_MODULE,
         .of_match_table = sunxi_pinctrl_test_match,
     },
 };

 static int __init sunxi_pinctrl_test_init(void)
 {
     int ret;
     ret = platform_driver_register(&sunxi_pinctrl_test_driver);
     if (IS_ERR_VALUE(ret)) {
         pr_warn("register sunxi pinctrl platform driver failed\n");
         return -EINVAL;
     }
     return ;
 }
 late_initcall(sunxi_pinctrl_test_init);

 MODULE_AUTHOR("Huangshr<huangshr@allwinnertech.com");
 MODULE_DESCRIPTION("Allwinner SUNXI Pinctrl driver test");
 MODULE_LICENSE("GPL");

一般应用是