【驱动代码移植高通平台之二十三】高通平台i2c设备驱动

原理图分析

假如该器件连接到GPIO18和GPIO19，查阅MSM8917的手册知道连接的i2c控制器为5

i2c控制器的配置

根据80-NU767-1 H文档进行配置

1 kernel里配置

i2c_5: i2c@7af5000 { /* BLSP2 QUP1 */

compatible = "qcom,i2c-msm-v2";

#address-cells = <1>;

#size-cells = <0>;

reg-names = "qup_phys_addr";

reg = <0x7af5000 0x600>;

interrupt-names = "qup_irq";

interrupts = <0 299 0>;

qcom,clk-freq-out = <400000>;

qcom,clk-freq-in = <19200000>;

clock-names = "iface_clk", "core_clk";

clocks = <&clock_gcc clk_gcc_blsp2_ahb_clk>,

<&clock_gcc clk_gcc_blsp2_qup1_i2c_apps_clk>;

pinctrl-names = "i2c_active", "i2c_sleep";

pinctrl-0 = <&i2c_5_active>;

pinctrl-1 = <&i2c_5_sleep>;

qcom,noise-rjct-scl = <0>;

qcom,noise-rjct-sda = <0>;

qcom,master-id = <84>;

dmas = <&dma_blsp2 4 64 0x20000020 0x20>,

<&dma_blsp2 5 32 0x20000020 0x20>;

dma-names = "tx", "rx";

};

2 trustzone里添加权限

设备驱动程序的编写

查询手册作为i2c slave的地址，寄存器，以及寄存器的读写时序

查询手册可知该款器件的i2c地址为0x3E，该器件比较简单只有三个寄存器（只是为了验证i2c驱动程序的框架，忽略具体寄存器的含义）

a 设备注册的方式

1 通过i2c_new_device的方法

2 通过设备树

&i2c_5 {

......

sm5109@3E {

compatible = "sm,sm5109";

reg = <0x3E>;

};

.......

};

b 构造i2c_driver结构体，填充其中的函数（probe，remove，id_table,driver里的of_match_table）

c.调用i2c_add_driver注册驱动程序

d.编写i2c对寄存器的读写函数:构造i2c_msg结构体，然后调用i2c_transfer

最后就是具体逻辑的编写

参考程序

设备注册的方式

#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/regulator/consumer.h>
#include <linux/firmware.h>
#include <linux/debugfs.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#define TAG "sm5109 "static int sm5109_i2c_read(struct i2c_client *client, char *writebuf,int writelen, char *readbuf, int readlen)
{int ret;if (writelen > 0) {struct i2c_msg msgs[] = {{.addr = client->addr,.flags = 0,.len = writelen,.buf = writebuf,},{.addr = client->addr,.flags = I2C_M_RD,.len = readlen,.buf = readbuf,},};ret = i2c_transfer(client->adapter, msgs, 2);if (ret < 0)dev_err(&client->dev, "%s: i2c read error.\n",__func__);} else {struct i2c_msg msgs[] = {{.addr = client->addr,.flags = I2C_M_RD,.len = readlen,.buf = readbuf,},};ret = i2c_transfer(client->adapter, msgs, 1);if (ret < 0)dev_err(&client->dev, "%s:i2c read error.\n", __func__);}return ret;
}static int sm5109_i2c_write(struct i2c_client *client, char *writebuf,int writelen)
{int ret;struct i2c_msg msgs[] = {{.addr = client->addr,.flags = 0,.len = writelen,.buf = writebuf,},};ret = i2c_transfer(client->adapter, msgs, 1);if (ret < 0)dev_err(&client->dev, "%s: i2c write error.\n", __func__);return ret;
}static int sm5109_write_reg(struct i2c_client *client, u8 addr, const u8 val)
{u8 buf[2] = {0};buf[0] = addr;buf[1] = val;return sm5109_i2c_write(client, buf, sizeof(buf));
}static int sm5109_read_reg(struct i2c_client *client, u8 addr, u8 *val)
{return sm5109_i2c_read(client, &addr, 1, val, 1);
}static int sm5109_probe(struct i2c_client *client,const struct i2c_device_id *id)
{u8 addr;u8 val;addr=0;sm5109_read_reg(client, addr , &val);printk(TAG"addr 0 is 0x%x\n", val);addr=1;sm5109_read_reg(client, addr , &val);printk(TAG"addr 1 is 0x%x\n", val);addr=3;sm5109_read_reg(client, addr , &val);printk(TAG"addr 3 is 0x%x\n", val);addr=3;val=3;sm5109_write_reg(client, addr , val);printk(TAG"%s\n", __func__);return 0;
}static int sm5109_remove(struct i2c_client *client)
{printk(TAG"%s\n", __func__);return 0;
}static const struct i2c_device_id sm5109_id[] = {{"sm5109", 0},{},
};MODULE_DEVICE_TABLE(i2c, sm5109_id);#ifdef CONFIG_OF
static struct of_device_id sm5109_match_table[] = {{ .compatible = "sm,sm5109",},{ },
};
#else
#define ft5x06_match_table NULL
#endifstatic struct i2c_driver sm5109_driver = {.probe = sm5109_probe,.remove = sm5109_remove,.driver = {.name = "sm5109",.owner = THIS_MODULE,.of_match_table = sm5109_match_table,},.id_table = sm5109_id,
};
static struct i2c_client *clt;static int __init sm5109_init(void)
{struct i2c_adapter *adap = i2c_get_adapter(5);struct i2c_board_info info = {.type   = "sm5109",.addr   = 0x3E,};printk(TAG"%s\n", __func__);clt = i2c_new_device(adap, &info);if (!clt) {printk(TAG"failed to i2c_new_device\n");}return i2c_add_driver(&sm5109_driver);
}
module_init(sm5109_init);static void __exit sm5109_exit(void)
{printk(TAG"%s\n", __func__);i2c_unregister_device(clt);i2c_del_driver(&sm5109_driver);
}
module_exit(sm5109_exit);MODULE_DESCRIPTION("sm5109 driver");
MODULE_LICENSE("GPL v2");

通过设备树的参考代码

#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/regulator/consumer.h>
#include <linux/firmware.h>
#include <linux/debugfs.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#define TAG "sm5109 "static int sm5109_i2c_read(struct i2c_client *client, char *writebuf,int writelen, char *readbuf, int readlen)
{int ret;if (writelen > 0) {struct i2c_msg msgs[] = {{.addr = client->addr,.flags = 0,.len = writelen,.buf = writebuf,},{.addr = client->addr,.flags = I2C_M_RD,.len = readlen,.buf = readbuf,},};ret = i2c_transfer(client->adapter, msgs, 2);if (ret < 0)dev_err(&client->dev, "%s: i2c read error.\n",__func__);} else {struct i2c_msg msgs[] = {{.addr = client->addr,.flags = I2C_M_RD,.len = readlen,.buf = readbuf,},};ret = i2c_transfer(client->adapter, msgs, 1);if (ret < 0)dev_err(&client->dev, "%s:i2c read error.\n", __func__);}return ret;
}static int sm5109_i2c_write(struct i2c_client *client, char *writebuf,int writelen)
{int ret;struct i2c_msg msgs[] = {{.addr = client->addr,.flags = 0,.len = writelen,.buf = writebuf,},};ret = i2c_transfer(client->adapter, msgs, 1);if (ret < 0)dev_err(&client->dev, "%s: i2c write error.\n", __func__);return ret;
}static int sm5109_write_reg(struct i2c_client *client, u8 addr, const u8 val)
{u8 buf[2] = {0};buf[0] = addr;buf[1] = val;return sm5109_i2c_write(client, buf, sizeof(buf));
}static int sm5109_read_reg(struct i2c_client *client, u8 addr, u8 *val)
{return sm5109_i2c_read(client, &addr, 1, val, 1);
}static int sm5109_probe(struct i2c_client *client,const struct i2c_device_id *id)
{u8 addr;u8 val;addr=0;sm5109_read_reg(client, addr , &val);printk(TAG"addr 0 is 0x%x\n", val);addr=1;sm5109_read_reg(client, addr , &val);printk(TAG"addr 1 is 0x%x\n", val);addr=3;sm5109_read_reg(client, addr , &val);printk(TAG"addr 3 is 0x%x\n", val);addr=3;val=3;sm5109_write_reg(client, addr , val);printk(TAG"%s\n", __func__);return 0;
}static int sm5109_remove(struct i2c_client *client)
{printk(TAG"%s\n", __func__);return 0;
}static const struct i2c_device_id sm5109_id[] = {{"sm5109", 0},{},
};MODULE_DEVICE_TABLE(i2c, sm5109_id);#ifdef CONFIG_OF
static struct of_device_id sm5109_match_table[] = {{ .compatible = "sm,sm5109",},{ },
};
#else
#define ft5x06_match_table NULL
#endifstatic struct i2c_driver sm5109_driver = {.probe = sm5109_probe,.remove = sm5109_remove,.driver = {.name = "sm5109",.owner = THIS_MODULE,.of_match_table = sm5109_match_table,},.id_table = sm5109_id,
};static int __init sm5109_init(void)
{return i2c_add_driver(&sm5109_driver);
}
module_init(sm5109_init);static void __exit sm5109_exit(void)
{printk(TAG"%s\n", __func__);i2c_del_driver(&sm5109_driver);
}
module_exit(sm5109_exit);MODULE_DESCRIPTION("sm5109 driver");
MODULE_LICENSE("GPL v2");

i2c用户空间测试程序

构造i2c_msg和i2c_rdwr_ioctl_data

然后使用ioctl系统调用发送给内核

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <getopt.h>
#include <sys/ioctl.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>static uint16_t slave_address;
static uint8_t reg_addr;
#define ARRAY_SIZE(a)   (sizeof(a) / sizeof(*a))/* i2c_test [path] [slave_addr] r reg_addr length* i2c_test [path] [slave_addr] w reg_addr value*/
static int do_i2c_write(int fd, char *writebuf, int writelen)
{int ret;struct i2c_msg msgs[] = {{.addr = slave_address,.flags = 0,.len = writelen,.buf = (void *)writebuf,},};struct i2c_rdwr_ioctl_data msgset = {.msgs = msgs,.nmsgs = ARRAY_SIZE(msgs),};ret = ioctl(fd, I2C_RDWR, &msgset);return ret;
}static int do_i2c_read(int fd, char *writebuf,int writelen, char *readbuf, int readlen)
{int ret;struct i2c_msg msgs[] = {{.addr = slave_address,.flags = 0,.len = writelen,.buf = (void *)writebuf,},{.addr = slave_address,.flags = I2C_M_RD,.len = readlen,.buf = (void *)readbuf,}};struct i2c_rdwr_ioctl_data msgset = {.msgs = msgs,.nmsgs = ARRAY_SIZE(msgs),};ret = ioctl(fd, I2C_RDWR, &msgset);return ret;
}void print_usage(char *file)
{printf("%s [path] [slave_addr] r reg_addr\n", file);printf("%s [path] [slave_addr] r reg_addr length\n", file);printf("%s [path] [slave_addr] w reg_addr value\n", file);printf("Example:\n");printf("%s /dev/i2c-5 0x3E r 3 1\n", file);printf("this command means that the adapter is 5, the slave address is 0x3E, read red 3 and read length is 1\n");
}int main(int argc, char **argv)
{int fd;char value;char wbuf[2];char* devname;int i,length = 0;if ((argc != 5) && (argc != 6)){print_usage(argv[0]);return -1;}devname = malloc(100);strcpy(devname,argv[1]);fd = open(devname, O_RDWR);if (fd < 0){printf("can't open %s\n", argv[1]);return -1;} else {printf("open %s success!\n", devname);}slave_address = strtoul(argv[2], NULL, 0);if ((strcmp(argv[3], "r")==0)||(strcmp(argv[3], "0")==0)) {if(argc == 5) {reg_addr = strtoul(argv[4], NULL, 0);do_i2c_read(fd, &reg_addr, 1, &value, 1);printf("reg 0x%x value is 0x%x\n", reg_addr, value);} else if (argc == 6) {reg_addr = strtoul(argv[4], NULL, 0);length = strtoul(argv[5], NULL, 0);for(i = 0 ; i < length; i++) {do_i2c_read(fd, &reg_addr, 1, &value, 1);printf("0x%02x 0x%02x\n", reg_addr, value);reg_addr++;}}} else if ((strcmp(argv[3], "w")==0)||(strcmp(argv[3], "1")==0) && argc == 6){reg_addr = strtoul(argv[4], NULL, 0);value = strtoul(argv[5], NULL, 0);wbuf[0] = reg_addr;wbuf[1] = value;do_i2c_write(fd, &wbuf, 2);printf("write reg 0x%x value is 0x%x\n", reg_addr, value);} else{print_usage(argv[0]);return -1;}free(devname);return 0;
}

假如编译出来的文件名为i2c_test

./i2c_test /dev/i2c-5 0x3E r 3 1

表明适配器是i2c5，设备地址是0x3E，r表示读，3表示寄存器地址，1表示读取的长度为1

./i2c_test /dev/i2c-5 0x3E r 0 3

寄存器地址为0，连续读取3个地址寄存器的数据

./i2c_test /dev/i2c-5 0x3E w 1 0x2F

w表示写，往地址为1的寄存器写0x2F

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【驱动代码移植高通平台之二十三】高通平台i2c设备驱动

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