fram.rar_FRAM linux_fm31256_fram_fram linux driv

/* * rtc-fm31256.c - RTC driver for Ramtron FM31256 I2C chip. * * Copyright (C) 2008 Sergey Lapin * Based on fm31256 driver by James Chapman and David Brownell * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/module.h> #include <linux/i2c.h> #include <linux/rtc.h> #include <linux/bcd.h> #include <linux/slab.h> #include <linux/miscdevice.h> #include <linux/semaphore.h> #define DEVICE_NAME "fm31256fram" #define CP_CONTROL 0x0b #define FM31256_CP_CONTROL_BIT_WP (3<<3) struct fm31256 { u8 reg_addr_time; u8 regs[1]; u8 flag; struct i2c_msg msg[2]; struct i2c_client *client; struct semaphore sem; /*并发控制用的信号量*/ }; static const struct i2c_device_id fm31256_id[] = { { "fm31256fram", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, fm31256_id); struct fm31256 *fm31256; static struct i2c_driver fm31256_driver; /*----------------------------------------------------------------------*/ #define FRAM_SIZE 256 /*ijsung: arch-indep function*/ static int FM31xx_open(struct inode *inode, struct file *file) { printk("Open file success!\n"); return 0; } static int FM31xx_release(struct inode *inode, struct file *file) { return 0; } ssize_t FM31xx_read(struct file *file, char *buf, size_t count, loff_t *ppos) { char* i2c_buf; char addr_buf[2]; struct i2c_client *client; int result ; loff_t off; off=*ppos; printk("%d\n",(unsigned int) off); client = fm31256->client; if (unlikely(off >= FRAM_SIZE)) return 0; if ((off + count) > FRAM_SIZE) count = FRAM_SIZE - off; if (unlikely(!count)) return count; i2c_buf=kmalloc(count,GFP_KERNEL); if(NULL==i2c_buf){ printk("Error:while kmalloc for the MEM!\n"); return -1; } if (down_interruptible(&fm31256->sem)){ goto err; } fm31256->regs[0]=i2c_smbus_read_byte_data(client, CP_CONTROL); /* Disabling Write Protect.mode */ if (fm31256->regs[0] & FM31256_CP_CONTROL_BIT_WP) { i2c_smbus_write_byte_data(client,CP_CONTROL, fm31256->regs[0] &~(FM31256_CP_CONTROL_BIT_WP)); //dev_warn(&client->dev, "Disabling Write Protectmode!\n"); } memset(i2c_buf,0,sizeof(u8)*count); addr_buf[0]=(off>>8)&0xff; addr_buf[1]=off&0xff; /* Messages to read time */ fm31256->msg[0].addr = client->addr; fm31256->msg[0].flags =0; fm31256->msg[0].len = 2; fm31256->msg[0].buf= addr_buf; fm31256->msg[1].addr = client->addr; fm31256->msg[1].flags = I2C_M_RD; fm31256->msg[1].len =count; fm31256->msg[1].buf = i2c_buf; result = i2c_transfer(to_i2c_adapter(fm31256->client->dev.parent),fm31256->msg, 2); if (result != 2) { dev_err(&client->dev, "%s error %d\n", "read", result); goto err; } if(copy_to_user ((void *)buf, i2c_buf, count)){ printk("Error:read count is not you want!\n"); goto err; } *ppos=off+count; if(NULL!=i2c_buf) kfree(i2c_buf); fm31256->regs[0]=FM31256_CP_CONTROL_BIT_WP; /* enabling Protect.mode */ i2c_smbus_write_byte_data(client,CP_CONTROL,fm31256->regs[0]); up(&fm31256->sem); //释放信号量 return count; err: up(&fm31256->sem); //释放信号量 if(NULL!=i2c_buf) kfree(i2c_buf); fm31256->regs[0]=FM31256_CP_CONTROL_BIT_WP; /* enabling Protect.mode */ i2c_smbus_write_byte_data(client,CP_CONTROL,fm31256->regs[0]); return -EIO; } ssize_t FM31xx_write(struct file *file, char *buf, size_t count, loff_t *ppos) { u8 *i2c_buf; struct i2c_client *client; int result ; loff_t off; off=*ppos; printk("%d\n",(unsigned int) off); client = fm31256->client; if (unlikely(off >= FRAM_SIZE)) return 0; if ((off + count) > FRAM_SIZE) count = FRAM_SIZE - off; if (unlikely(!count)) return count; i2c_buf=kmalloc((count+2),GFP_KERNEL); if(NULL==i2c_buf){ printk("Error:while kmalloc for the MEM!\n"); return -1; } if (down_interruptible(&fm31256->sem)){ goto err; } memset(i2c_buf,0,(count+2)); if( copy_from_user(&i2c_buf[2],buf,count) ){ printk("Error:write count is not you want!\n"); goto err; } fm31256->regs[0]=i2c_smbus_read_byte_data(client, CP_CONTROL); /* Disabling Write Protect.mode */ if (fm31256->regs[0] & FM31256_CP_CONTROL_BIT_WP) { i2c_smbus_write_byte_data(client,CP_CONTROL, fm31256->regs[0] & ~(FM31256_CP_CONTROL_BIT_WP)); //dev_warn(&client->dev, "Disabling Write Protectmode!\n"); } i2c_buf[0]=(off>>8)&0xff; i2c_buf[1]=off&0xff; /* Messages to read time */ fm31256->msg[0].addr = client->addr; fm31256->msg[0].flags =0; fm31256->msg[0].len =count+2; fm31256->msg[0].buf=i2c_buf; result = i2c_transfer(to_i2c_adapter(fm31256->client->dev.parent), fm31256->msg, 1); if (result != 1) { dev_err(&client->dev, "%s error %d\n", "write", result); goto err; } *ppos=off+count; if(NULL!=i2c_buf) kfree(i2c_buf); fm31256->regs[0]=FM31256_CP_CONTROL_BIT_WP; /* enabling Protect.mode */ i2c_smbus_write_byte_data(client,CP_CONTROL,fm31256->regs[0]); up(&fm31256->sem); //释放信号量 return count; err: up(&fm31256->sem); //释放信号量 if(NULL!=i2c_buf) kfree(i2c_buf); fm31256->regs[0]=FM31256_CP_CONTROL_BIT_WP; /* enabling Protect.mode */ i2c_smbus_write_byte_data(client,CP_CONTROL,fm31256->regs[0]); return -EIO; } static loff_t FM31xx_llseek (struct file *filp, loff_t off,int whence) { loff_t newpos=0; switch(whence){ case SEEK_SET: newpos = off; break; case SEEK_CUR: newpos = filp->f_pos + off; break; case 2: newpos = FRAM_SIZE + off; break; default: return -EINVAL; } if (newpos < 0) return -EINVAL; filp->f_pos= newpos; return newpos; } /*文件操作结构体*/ static struct file_operations dev_fops = { .owner = THIS_MODULE, .read = FM31xx_read, .write = FM31xx_write, .open = FM31xx_open, .llseek = FM31xx_llseek, .release = FM31xx_release, }; static struct miscdevice fm31xfram_miscdev ={ .minor =MISC_DYNAMIC_MINOR, .name = DEVICE_NAME, .fops = &dev_fops,//关联文件操作 }; static int __devinit fm31256_probe(struct i2c_client *client, const struct i2c_device_id *id) { printk("fm31256_probe.....!\n"); int err = -ENODEV; int tmp; struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); if (!i2c_check_functionality(adapter,I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) return -EIO; fm31256 = kzalloc(sizeof(struct fm31256), GFP_KERNEL); if (!fm31256) return -ENOMEM; fm31256->flag=0; fm31256->client = client; i2c_set_clientdata(client, fm31256); sema_init(&fm31256->sem,1); /*初始化信号量*/ if (misc_register(&fm31xfram_miscdev)==0){ fm31256->flag=1; };//返回0，成功，负数，不成功 return 0; exit_free: kfree(fm31256); return err; } static int __devexit fm31256_remove(struct i2c_client *client) { kfree(fm31256); return 0; } static struct i2c_driver fm31256_driver = { .driver = { .name = "fm31256fram", .owner = THIS_MODULE, }, .probe = fm31256_probe, .remove = __devexit_p(fm31256_remove), .id_table = fm31256_id, }; static int __init fm31256_init(void) { return i2c_add_driver(&fm31256_driver); } module_init(fm31256_init); static void __exit fm31256_exit(void) { if(fm31256->flag){ if (misc_deregister(&fm31xfram_miscdev)==0){ printk (DEVICE_NAME"\texit\n"); };//返回0，成功，负数，不成功 } i2c_del_driver(&fm31256_driver); } module_exit(fm31256_exit); MODULE_DESCRIPTION("FRAM driver for FM31256"); MODULE_AUTHOR("AUTHOR by hust zkc"); MODULE_LICENSE("GPL");