ads1256 linux 驱动

#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.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/uaccess.h> #include <asm/io.h> #include "ads1256_spi.h" #include <linux/unistd.h> #define ADS1256_CNT 1 #define ADS1256_NAME "ads1256" #define ADS1256_TRANSFORM_TIME_US 309 static int ads1256_probe(struct spi_device *spi); static int ads1256_remove(struct spi_device *spi); static int ads1256_open(struct inode *inode, struct file *filp); static ssize_t ads1256_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offt); static ssize_t ads1256_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off); static int ads1256_release(struct inode *inode, struct file *filp); struct ads1256_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 */ int pdwn_gpio; int cs_gpio; /* cs所使用的GPIO编号 */ int reset_gpio; /* reset所使用的GPIO编号 */ int drdy_gpio; /* drdy所使用的GPIO编号 */ unsigned char channels[8]; /* 采样通道，最多8个 */ unsigned char channel_num; /* 采样通道数量 */ int delay_us; /* 采样间隔时间 */ void *private_data; /* 私有数据 */ }; static struct ads1256_dev ads1256dev; static const struct spi_device_id ads1256_id[] = { {"alientek,ads1256", 0}, {}}; static const struct of_device_id ads1256_of_match[] = { {.compatible = "alientek,ads1256"}, {/* Sentinel */}}; static struct spi_driver ads1256_driver = { .probe = ads1256_probe, .remove = ads1256_remove, .driver = { .owner = THIS_MODULE, .name = "ads1256", .of_match_table = ads1256_of_match, }, .id_table = ads1256_id, }; /* ads1256操作函数 */ static const struct file_operations ads1256_ops = { .owner = THIS_MODULE, .open = ads1256_open, .read = ads1256_read, .write = ads1256_write, .release = ads1256_release, }; static int ads1256_transfer_multibyte(struct ads1256_dev *dev, unsigned char *wbuf, unsigned char *rbuf, unsigned char len) { int ret = 0; struct spi_message m; struct spi_transfer t = {0}; struct spi_device *spi = (struct spi_device *)dev->private_data; /* 一共发送len个字节的数据*/ t.tx_buf = wbuf; /* 要发送的数据 */ t.rx_buf = rbuf; t.len = len; /* 传输长度 */ 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 */ return -ret; } static unsigned char ads1256_transfer(struct ads1256_dev *dev, unsigned char byte) { int ret = -1; unsigned char txdata[1]; unsigned char rxdata[1]; struct spi_message m; struct spi_transfer t = {0}; struct spi_device *spi = (struct spi_device *)dev->private_data; /* 一共发送1个字节的数据，第一个字节为 寄存器首地址，一共要读取len个字节长度的数据，*/ txdata[0] = byte | 0x80; /* 写数据的时候首寄存器地址bit8要置1 */ t.tx_buf = txdata; /* 要发送的数据 */ t.rx_buf = rxdata; /* 要读取的数据 */ t.len = 1; /* 发送的长度 */ 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 */ if (ret) { rxdata[0] = 0; printk("error transfer data!\r\n"); } printk("recv transfer data! %x\r\n",rxdata[0]); return rxdata[0]; } static int ads1256_read_global_reg(struct ads1256_dev *dev,uint8_t index,uint8_t *dat) { unsigned char wbuf[8]; unsigned char rbuf[8]; /* 设置采样通道 */ gpio_set_value(dev->cs_gpio, 0); while (gpio_get_value(dev->drdy_gpio)) ; wbuf[0] = ADS1256_CMD_RREG | (index & 0xF); wbuf[1] = 0; ads1256_transfer_multibyte(dev, wbuf, rbuf, 2); dat[0] = ads1256_transfer(dev, 0xFF); while (gpio_get_value(dev->drdy_gpio)); gpio_set_value(dev->cs_gpio, 1); return 1; } static int ads1256_read_channel(struct ads1256_dev *dev, unsigned char channel) { unsigned char i = 0; unsigned int r = 0; int sum = 0; unsigned char wbuf[8]; unsigned char rbuf[8]; /* 设置采样通道 */ gpio_set_value(dev->cs_gpio, 0); while (gpio_get_value(dev->drdy_gpio)) ; wbuf[0] = ADS1256_CMD_WREG | (ADS1256_MUX & 0xF); wbuf[1] = 0; ads1256_transfer_multibyte(dev, wbuf, rbuf, 2); wbuf[0] = channel; ads1256_transfer_multibyte(dev, wbuf, rbuf, 1); while (gpio_get_value(dev->drdy_gpio)) ; /* 读取转换结果 */ wbuf[0] = ADS1256_CMD_SYNC; wbuf[1] = ADS1256_CMD_WAKEUP; wbuf[2] = ADS1256_CMD_RDATA; ads1256_transfer_multibyte(dev, wbuf, rbuf, 3); wbuf[0] = 0xFF; wbuf[1] = 0xFF; wbuf[2] = 0xFF; memset(rbuf, 0, 3); ads1256_transfer_multibyte(dev, wbuf, rbuf, 3); for (i = 0; i < 3; i++) { sum = sum << 8; r = rbuf[i]; sum |= r; } printk("sum %x, channal %x\r\n",sum,channel); if (sum > 0x7FFFFF) { // 负值转换 // sum |= ~0 << 23; // sum = ~(sum - 1); sum -= 0x1000000; } while (gpio_get_value(dev->drdy_gpio)) ; gpio_set_value(dev->cs_gpio, 1); return sum; } struct write_data { unsigned char cmd; unsigned char length; unsigned char param[8]; /* 最多8个参数 */ }; static int ads1256_write_string_to_dev(struct ads1256_dev *dev, const char *buf, size_t cnt) { size_t index = 0; struct write_data *data_p; int temp; while (index < cnt) { if (cnt - index < 3) { return index; } data_p = (struct write_data *)&buf[index]; switch (data_p->cmd) { case SET_CHANNELS: if (data_p->length > 8 || index + 1 + data_p->length >= cnt) { return index;/* 参数�?误 或 剩余长度不够 */ } dev->channel_num = data_p->length; /* 设置通道数量 */ memcpy(dev->channels, data_p->param, dev->channel_num); /* 设置通道序列 */ ads1256_read_channel(dev, dev->channels[0]);/* 重置通道 */ index = index + data_p->length + 2; break; case SET_FREQUENCY: if (data_p->length != 4 || index + 1 + data_p->length >= cnt) { return index;/* 参数错误 或 剩余长度不够 */ } temp = (data_p->param[0] << 24) + (data_p->param[1] << 16) + (data_p->param[2] << 8) + data_p->param[3]; temp = 1000000 / temp - ADS1256_TRANSFORM_TIME_US; dev->delay_us = temp > 0 ? temp : 0; index = index + data_p->length + 2; break; default: return index; } } return index; } static int ads1256_open(struct inode *inode, struct file *filp) { filp->private_data = &ads1256dev; /* 设置私有数据 */ return 0; } static ssize_t ads1256_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offt) { int retvalue; unsigned char *databuf; struct ads1256_dev *dev = (struct ads1256_dev *)filp->private_data; databuf = kzalloc(cnt, GFP_KERNEL); if (!databuf) { return -ENOMEM; } retvalue = copy_from_user(databuf, buf, cnt); if (retvalue < 0) { printk("kernel write failed!\r\n"); retvalue = -EFAULT; goto out1; } retvalue = ads1256_write_string_to_dev(dev, databuf, cnt); out1: kfree(databuf); return retvalue; } static ssize_t ads1256_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off) { int err = 0; int *result; int length; int index = 1; /* 浠??开始，实际采样是从通道0开始 */ struct ads1256_dev *dev = (struct ads1256_dev *)filp->private_data; /* 计算采样点个数 */ length = cnt / 4; /* 开内存空间 */ result = kzalloc(length * 4, GFP_KERNEL); if (!result) { return -ENOMEM; } udelay(dev->delay_us); /* 采样 */ while (index < length + 1) { result[index - 1] = ads1256_read_channel(dev, dev->channels[index % dev->channel_num]); index++; udelay(dev->delay_us); } /* 重置通道 */ ads1256_read_channel(dev, dev->channels[0]); err = copy_to_user(buf, result, length * 4); kfree(result); return len