高通 linux 3.0 配置及控制GPIO的方式

linux配置GPIO的方式

 

 

linux配置GPIO的方式

 

Kernel阶段的控制

1  使用Pinctrl框架控制

 

(1)  设备树文件相关节点

sn7326_power_pin {  

                qcom,pins = <&gp 3>;  

                qcom,num-grp-pins = <1>;  

                qcom,pin-func = <0>;  

                 

                label ="sn7326-power-pin";  

                sn7326_power_active:sn7326_power_active {  

                        drive-strength =<6>;  

                        bias-pull-up;  

                        output-high;  

                         

                };  

   

                sn7326_power_sleep:sn7326_power_sleep {  

                        drive-strength =<2>;  

                        bias-pull-down;  

                        output-low;  

                };  

       };  

   

sn@58 {  

                     compatible= "sn,sn7326";  

                     reg= <0x58>;                     

                       pinctrl-names ="active","sleep";  

                       pinctrl-0 = <&sn7326_power_active>;  

                       pinctrl-1 =<&sn7326_power_sleep>;  

                     interrupt-parent= <&msm_gpio>;  

                     interrupts= <98 0x02>;  

                     …  

          sn7326,pwr-en-gpio=<&msm_gpio 3 0x00>;//GPIO控制方式  

              };  

 

(2)  Pinctrl控制代码

static int sn7326_pinctrl_init(structsn7326_chip_data *data)  

{  

       struct i2c_client *client = data->client;  

   

       data->pinctrl = devm_pinctrl_get(&client->dev);  

       if (IS_ERR_OR_NULL(data->pinctrl)) {  

                dev_err(&client->dev,"Failed to get pinctrl\n");  

                returnPTR_ERR(data->pinctrl);  

       }  

   

       data->pin_active =  

               pinctrl_lookup_state(data->pinctrl, "active");  

       if (IS_ERR_OR_NULL(data->pin_active)) {  

                dev_err(&client->dev,"Failed to look up default state\n");  

                returnPTR_ERR(data->pin_active);  

       }  

   

       data->pin_sleep =  

               pinctrl_lookup_state(data->pinctrl, "sleep");  

       if (IS_ERR_OR_NULL(data->pin_sleep)) {  

                dev_err(&client->dev,"Failed to look up sleep state\n");  

                returnPTR_ERR(data->pin_sleep);  

       }  

   

       return 0;  

}  

   

   

ret =pinctrl_select_state(chip_data->pinctrl, chip_data->pin_active);  

       if (ret) {  

                dev_err(&client->dev,  

                        "Can't selectpinctrl default state\n");  

                goto free_pdata;  

       }  

 

这里的chip_data->pin_active指向sn7326_power_active。

  

 

 

2  使用GPIO控制

(1)  设备树相关节点

sn@58 {  

                     compatible= "sn,sn7326";  

                     reg= <0x58>;                     

                     …  

          sn7326,pwr-en-gpio=<&msm_gpio 3 0x00>;//GPIO控制方式  

              };  

 

(2)  代码控制

static int sn7326_kpd_parse_dt(structdevice *dev,struct sn7326_pdata *pdata)  

{  

       intret = 0;  

        

       structdevice_node *np = dev->of_node;  

       pdata->pwr_en_gpio= of_get_named_gpio_flags(np, "sn7326,pwr-en-gpio",0, NULL);  

       if(gpio_is_valid(pdata->pwr_en_gpio)){  

              ret= gpio_request(pdata->pwr_en_gpio, "sn7326_pwr_en");  

              if(ret){  

                     dev_err(dev,"%s: pwr-en gpio request failed.\n", __func__);  

                     goto free_rst;  

              }  

              gpio_direction_output(pdata->pwr_en_gpio, 1);  

       }  

   

       pdata->irq_gpio= of_get_named_gpio_flags(np, "sn7326,interrupt-gpio",0, NULL);  

       if(!gpio_is_valid(pdata->irq_gpio)) {  

              gotofree_pwr_en;  

       }  

        

       returnret;  

   

free_pwr_en:  

       if(gpio_is_valid(pdata->pwr_en_gpio))  

                     gpio_free(pdata->pwr_en_gpio);  

       returnret;  

}