正点原子Linux开发板 spi内核驱动 0.96寸ips屏教程

首先选择模块
设备树配置
spi驱动程序（用的spi_driver）
app

最近做下底层SPI驱动来驱动IPS屏，本来想实现这种效果：

后面想着暂时不做frambuffer，用用spi巩固一下吧，于是就有了本次记录。

首先选择模块

去tb某店买了两块ips屏幕，一块0.96寸，一块1.3寸（当时想着两个都用下，大的显示的多些）
显示屏如下：
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200620172251526.JPG?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1JheW1vbmRfOTdf,size_16,color_FFFFFF,t_70
拿到代码后，找的stm32的1.3寸屏程序作为参考，开始移植1.3寸屏到linux上去。折腾了一上午加半个下午，显示屏就是没亮？what 我把每个发过去的spi数据都打印出来，都是对的，我惊了。脑袋嗡嗡的了，罢了换0.96寸的屏，重新配置初始化命令，刷新屏幕，亮了！我崩溃了，合着屏幕是坏的？示例程序有问题？后面检查发现spi->mode = SPI_MODE_2; /*MODE0，CPOL=0，CPHA=0 //出问题的地方!!!*/spi模式需要改。
驱动1.3寸显示屏请移步如下链接:
1.3寸ips显示屏驱动地址
0.96寸的屏幕，以下是代码部分：

设备树配置

     //功能引脚pinctrl_ipsRes: ipsRes {    //屏幕复位u引脚fsl,pins = <MX6UL_PAD_GPIO1_IO01__GPIO1_IO01        0x10B0 /* LED0 */>;};  pinctrl_ipsDc: ipsDc {      //屏幕dc(data or command)u引脚fsl,pins = <MX6UL_PAD_GPIO1_IO04__GPIO1_IO04        0x10B0 >;};..............//附加节点&ecspi3 {fsl,spi-num-chipselects = <1>;cs-gpio = <&gpio1 20 GPIO_ACTIVE_LOW>; /* cant't use cs-gpios! */pinctrl-names = "default";pinctrl-0 = <&pinctrl_ecspi3>;status = "okay";spidev: ipsTft@0 {compatible = "alientek,ipsTft";spi-max-frequency = <1000000000>;  //频率无脑给的很大，但是刷新频率快不起来reg = <0>;};
};

spi驱动程序（用的spi_driver）

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of_gpio.h>
#include <linux/semaphore.h>
#include <linux/timer.h>
#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/spi/spi.h>
#define ipsTft_CNT  1
#define ipsTft_NAME "ipsTft"
#define LCD_W 240
#define LCD_H 240
#define X_MAX_PIXEL         160
#define Y_MAX_PIXEL         80
#define RED     0xf800
#define GREEN   0x07e0
#define BLUE    0x001f
#define WHITE   0xffff
#define BLACK   0x0000
#define YELLOW  0xFFE0
#define GRAY0   0xEF7D      //»ÒÉ«0 3165 00110 001011 00101
#define GRAY1   0x8410          //»ÒÉ«1      00000 000000 00000
#define GRAY2   0x4208          //»ÒÉ«2  1111111111011111
u8 buf[9] = {RED, GREEN, BLUE,WHITE, BLACK,  YELLOW,GRAY0 ,GRAY1 ,GRAY2
};
struct ipsTft_dev {dev_t devid;             /* 设备号   */struct cdev cdev;            /* cdev     */struct class *class;      /* 类        */struct device *device;        /* 设备    */struct device_node   *nd;    /* 设备节点 */int major;                    /* 主设备号 */void *private_data;           /* 私有数据         */int dc_gpio;              /* 片选所使用的GPIO编号     */int res_gpio;                 /*ips屏幕复位引脚*/int cs_gpio;                    /*磁力计的cs*/
};
static struct ipsTft_dev ipsTftdev;
void ipsTft_reginit(struct ipsTft_dev *dev);
// struct spi_lcd_cmd{//     u8  reg_addr; // command//     u8  len;  //需要从spi_lcd_datas数组里发出数据字节数//     int delay_ms; //此命令发送数据完成后，需延时多久// }cmds[] = {//     {0x36, 1, 0},//     {0x3A, 1, 0},//     {0xB2, 5, 0},//     {0xB7, 1, 0},//     {0xBB, 1, 0},//     {0xC0, 1, 0},//     {0xC2, 1, 0},//     {0xC3, 1, 0},//     {0xC4, 1, 0},//     {0xC6, 1, 0},//     {0xD0, 2, 0},//     {0xE0, 14, 0},//     {0xE1, 14, 0},//     {0x21, 0, 0},//     {0x11, 0, 0},//     {0x29, 0, 0},// };
// u8 spi_lcd_datas[] = {//     0x00, //     0x05,//     0x0c,0x0c,0x00,0x33,0x33,//     0x35,//     0x19,//     0x2c,//     0x01,//     0x12, //     0x20, //     0x0F, //     0xA4,0xA1,//     0xD0,0x04,0x0D,0x11,0x13,0x2B,0x3F,0x54,0x4C,0x18,0x0D,0x0B,0x1F,0x23,//     0xD0,0x04,0x0C,0x11,0x13,0x2C,0x3F,0x44,0x51,0x2F,0x1F,0x1F,0x20,0x23,// };
struct spi_lcd_cmd{u8  reg_addr; // commandu8  len;  //需要从spi_lcd_datas数组里发出数据字节数int delay_ms; //此命令发送数据完成后，需延时多久
}cmds[] = {{0x11, 0, 120},{0x21, 0, 0},{0x21, 0, 0},{0xB1, 3, 0},{0xB2, 3, 0},{0xB3, 6, 0},{0xB4, 1, 0},{0xC0, 3, 0},{0xC1, 1, 0},{0xC2, 2, 0},{0xC3, 2, 0},{0xC4, 2, 0},{0xC5, 1, 0},{0xE0, 16, 0},{0xE1, 16, 0},{0x3A, 1, 0},{0x36, 1, 0},{0x29, 0, 0},
};
u8 spi_lcd_datas[] = {0x05,0x3A,0x3A,0x05,0x3A,0x3A,0x05,0x3A,0x3A,0x05,0x3A,0x3A,0x03,0x62,0x02,0x04,0xC0,0x0D,0x00,0x8D,0x6A,0x8D,0xEE,0x0E,0x10,0x0E,0x02,0x03,0x0E,0x07,0x02,0x07,0x0A,0x12,0x27,0x37,0x00,0x0D,0x0E,0x10,0x10,0x0E,0x03,0x03,0x0F,0x06,0x02,0x08,0x0A,0x13,0x26,0x36,0x00,0x0D,0x0E,0x10,0x05,    0xA8,
};
/** @description   : 向ipsTft多个寄存器写入数据* @param - dev:  ipsTft设备* @param - reg:  要写入的寄存器首地址* @param - val:  要写入的数据缓冲区* @param - len:  要写入的数据长度* @return       :   操作结果*/
static s32 ipsTft_write_regs(struct ipsTft_dev *dev,u8 *buf, u8 len)
{int ret;struct spi_message m;struct spi_transfer *t;struct spi_device *spi = (struct spi_device *)dev->private_data;t = kzalloc(sizeof(struct spi_transfer), GFP_KERNEL); /* 申请内存 *//* 发送要写入的数据 */t->tx_buf = buf;            /* 要写入的数据 */t->len = len;               /* 写入的字节数 */spi_message_init(&m);       /* 初始化spi_message */spi_message_add_tail(t, &m);/* 将spi_transfer添加到spi_message队列 */ret = spi_sync(spi, &m);    /* 同步发送 */kfree(t);                 /* 释放内存 */return ret;
}
/** @description   : 向ipsTft指定寄存器写入指定的值，写一个寄存器* @param - dev:  ipsTft设备* @param - reg:  要写的寄存器* @param - data: 要写入的值* @return   :    无*/
static void ipsTft_write_onereg(struct ipsTft_dev *dev, u8 buf)
{ipsTft_write_regs(dev,&buf, 1);//spi_write(dev,&buf, 1);
}
/*funciton: 写一个命令
*/
void write_command(struct ipsTft_dev *dev, u8 cmd)
{// dc , command:0gpio_set_value(dev->dc_gpio, 0); ipsTft_write_onereg(dev,cmd);
}
/*funciton: 写一个数据
*/
void write_data(struct ipsTft_dev *dev, u8 data)
{gpio_set_value(dev->dc_gpio, 1);ipsTft_write_onereg(dev,data);
}
/*funciton: 写一个数据
*/
static void write_datas(struct ipsTft_dev *dev, int data,int len)
{gpio_set_value(dev->dc_gpio, 1);ipsTft_write_regs(dev,(u8 *)&data,len);
}
/** @description       : 打开设备* @param - inode     : 传递给驱动的inode* @param - filp   : 设备文件，file结构体有个叫做pr似有ate_data的成员变量*                       一般在open的时候将private_data似有向设备结构体。* @return            : 0 成功;其他 失败*/
static int ipsTft_open(struct inode *inode, struct file *filp)
{filp->private_data = &ipsTftdev; /* 设置私有数据 */ipsTft_reginit(&ipsTftdev);return 0;
}
/** @description       : 关闭/释放设备* @param - filp   : 要关闭的设备文件(文件描述符)* @return             : 0 成功;其他 失败*/
static int ipsTft_release(struct inode *inode, struct file *filp)
{return 0;
}
/* ipsTft操作函数 */
static const struct file_operations ipsTft_ops = {.owner = THIS_MODULE,.open = ipsTft_open,.release = ipsTft_release,
};
void Address_set(struct ipsTft_dev *dev,unsigned int x1,unsigned int y1,unsigned int x2,unsigned int y2)
{ write_command(dev,0x2a);write_data(dev,x1>>8);write_data(dev,x1);write_data(dev,x2>>8);write_data(dev,x2);write_command(dev,0x2b);write_data(dev,y1>>8);write_data(dev,y1);write_data(dev,y2>>8);write_data(dev,y2);write_command(dev,0x2C);
}
/*刷屏函数
*/
void LCD_Clear(struct ipsTft_dev *dev)
{u16 i,j;   Address_set(dev,0,0,LCD_W-1,LCD_H-1);for(i=0;i<LCD_W;i++){for (j=0;j<LCD_H;j++){//write_datas(dev,0xF800,2);        //全红        write_data(dev,0xF800>>8);write_data(dev,0xF800&0xFF);}}
}
/*************************************************0.96'*************************************************/
void Lcd_SetRegion(struct ipsTft_dev *dev,u16 x_start,u16 y_start,u16 x_end,u16 y_end)
{       write_command(dev,0x2a);write_data(dev,0x00);write_data(dev,x_start+1);write_data(dev,0x00);write_data(dev,x_end+1);write_command(dev,0x2b);write_data(dev,0x00);write_data(dev,y_start+0x1A);write_data(dev,0x00);write_data(dev,y_end+0x1A);  write_command(dev,0x2c);
}
/*************************************************
0.96'显示屏填充函数
*************************************************/
void Lcd_Clear_small(struct ipsTft_dev *dev,u16 Color)
{   unsigned int i,m;Lcd_SetRegion(dev,0,0,X_MAX_PIXEL-1,Y_MAX_PIXEL-1);write_command(dev,0x2C);for(i=0;i<X_MAX_PIXEL;i++)for(m=0;m<Y_MAX_PIXEL;m++){   //LCD_WriteData_16Bit(Color);write_data(dev,Color>>8);write_data(dev,Color&0xFF);}
}
/** ipsTft内部寄存器初始化函数 * @param      : 无* @return   : 无*/
void ipsTft_reginit(struct ipsTft_dev *dev)
{int i, j, n;gpio_set_value(ipsTftdev.res_gpio, 0);mdelay(500);gpio_set_value(ipsTftdev.res_gpio, 1);mdelay(500);n = 0; // n用于记录数据数组spi_lcd_datas的位置//发命令，并发出命令所需的数据for (i = 0; i < ARRAY_SIZE(cmds); i++) //命令{write_command(dev, cmds[i].reg_addr);for (j = 0; j < cmds[i].len; j++) //发出命令后，需要发出的数据if(cmds[i].len!=0)write_data(dev, spi_lcd_datas[n++]);printk("the n is %d\n",n);if (cmds[i].delay_ms) //如有延时则延时mdelay(cmds[i].delay_ms);}n=0;while(n<9){Lcd_Clear_small(dev,*(buf+n));n++;mdelay(1000);}printk("ips init finish!\n");
}/** @description     : spi驱动的probe函数，当驱动与*                    设备匹配以后此函数就会执行* @param - client  : spi设备* @param - id      : spi设备ID* */
static int ipsTft_probe(struct spi_device *spi)
{int ret = 0;/* 1、构建设备号 */if (ipsTftdev.major) {ipsTftdev.devid = MKDEV(ipsTftdev.major, 0);register_chrdev_region(ipsTftdev.devid, ipsTft_CNT, ipsTft_NAME);} else {alloc_chrdev_region(&ipsTftdev.devid, 0, ipsTft_CNT, ipsTft_NAME);ipsTftdev.major = MAJOR(ipsTftdev.devid);}/* 2、注册设备 */cdev_init(&ipsTftdev.cdev, &ipsTft_ops);cdev_add(&ipsTftdev.cdev, ipsTftdev.devid, ipsTft_CNT);/* 3、创建类 */ipsTftdev.class = class_create(THIS_MODULE, ipsTft_NAME);if (IS_ERR(ipsTftdev.class)) {return PTR_ERR(ipsTftdev.class);}/* 4、创建设备 */ipsTftdev.device = device_create(ipsTftdev.class, NULL, ipsTftdev.devid, NULL, ipsTft_NAME);if (IS_ERR(ipsTftdev.device)) {return PTR_ERR(ipsTftdev.device);}/* 获取设备树中cs片选信号 */ipsTftdev.nd = of_find_node_by_path("/soc/aips-bus@02000000/spba-bus@02000000/ecspi@02010000");if(ipsTftdev.nd == NULL) {printk("ecspi3 node not find!\r\n");return -EINVAL;}/* 2、 获取设备树中的gpio属性，得到BEEP所使用的BEEP编号 */ipsTftdev.cs_gpio = of_get_named_gpio(ipsTftdev.nd, "cs-gpio", 0);if(ipsTftdev.cs_gpio < 0) {printk("can't get cs-gpio");return -EINVAL;}ipsTftdev.nd = of_find_node_by_path("/ipsRes");if(ipsTftdev.nd == NULL) {printk("res-gpio node not find!\r\n");return -EINVAL;}ipsTftdev.res_gpio = of_get_named_gpio(ipsTftdev.nd, "res-gpio", 0);if(ipsTftdev.res_gpio < 0) {printk("can't get res-gpio");return -EINVAL;}ipsTftdev.nd = of_find_node_by_path("/ipsDc");if(ipsTftdev.nd == NULL) {printk("ipsDcgpio node not find!\r\n");return -EINVAL;}ipsTftdev.dc_gpio = of_get_named_gpio(ipsTftdev.nd, "dc-gpio", 0);if(ipsTftdev.dc_gpio < 0) {printk("can't get ipsDc-gpio");return -EINVAL;}/* 3、设置GPIO1_IO20为输出，并且输出高电平 */ret = gpio_direction_output(ipsTftdev.cs_gpio, 1);if(ret < 0) {printk("can't set cs gpio!\r\n");}ret = gpio_direction_output(ipsTftdev.res_gpio, 1);if(ret < 0) {printk("can't set res gpio!\r\n");}ret = gpio_direction_output(ipsTftdev.dc_gpio, 1);if(ret < 0) {printk("can't set dc gpio!\r\n");}/*初始化spi_device */spi->mode = SPI_MODE_0;  /*MODE0，CPOL=0，CPHA=0*/spi_setup(spi);ipsTftdev.private_data = spi; /* 设置私有数据 *//* 初始化ipsTft内部寄存器 */ipsTft_reginit(&ipsTftdev);        return 0;
}
/** @description     : spi驱动的remove函数，移除spi驱动的时候此函数会执行* @param - client    : spi设备* @return          : 0，成功;其他负值,失败*/
static int ipsTft_remove(struct spi_device *spi)
{/* 删除设备 */cdev_del(&ipsTftdev.cdev);unregister_chrdev_region(ipsTftdev.devid, ipsTft_CNT);/* 注销掉类和设备 */device_destroy(ipsTftdev.class, ipsTftdev.devid);class_destroy(ipsTftdev.class);return 0;
}
/* 传统匹配方式ID列表 */
static const struct spi_device_id ipsTft_id[] = {{"alientek,ipsTft", 0},  {}
};
/* 设备树匹配列表 */
static const struct of_device_id ipsTft_of_match[] = {{ .compatible = "alientek,ipsTft" },{ /* Sentinel */ }
};
/* SPI驱动结构体 */
static struct spi_driver ipsTft_driver = {.probe = ipsTft_probe,.remove = ipsTft_remove,.driver = {.owner = THIS_MODULE,.name = "ipsTft",.of_match_table = ipsTft_of_match, },.id_table = ipsTft_id,
};
/** @description   : 驱动入口函数* @param       : 无* @return       : 无*/
static int __init ipsTft_init(void)
{return spi_register_driver(&ipsTft_driver);
}
/** @description   : 驱动出口函数* @param       : 无* @return       : 无*/
static void __exit ipsTft_exit(void)
{spi_unregister_driver(&ipsTft_driver);
}
module_init(ipsTft_init);
module_exit(ipsTft_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("raymond");

insmode 一下就行了