spi總線驅(qū)動-linux下開發(fā)

Linuxspi驅(qū)動開發(fā)

下面的代碼和處理器沒有太大關(guān)系，這也是spi子系統(tǒng)的分層特點。#include#include#include<linux/spi/spi.h>#include<linux/init.h>#include<linux/module.h>#include<linux/device.h>#include<linux/interrupt.h>#include<linux/mutex.h>#include<linux/slab.h>//#include#define/*FlashOperatingCommands #defineCMD_WRITE_ENABLE #define#define/*StatusRegisterbits.#define /*Writeinprogress#define /*Writeenablelatch/*IDNumbers#define#define/*Definemaxtimestocheckstatusregisterbeforewegiveup.#define #defineCMD_SZstructm25p10astruct struct cmd[CMD_SZInternalHelperReadthestatusregister,returningitsvalueintheReturnthestatusregisterReturnsnegativeiferrorstaticintread_sr(structm25p10a{ssize_tu8code=CMD_RDSR;u8val;retval=spi_write_then_read(flash->spi,&code,1,&val,1);if(retval<0){dev_err(&flash->spi->dev,"error%dreading(int)retval);returnretval;}return}Serviceroutinetoreadstatusregisteruntilready,ortimeoutReturnsnon-zeroifstaticintwait_till_ready(structm25p10a{intsr;/*onechipguaranteesmax5msecwaithereafterpage*butpotentiallythreeseconds(!)afterpagefor(count=0;count<MAX_READY_WAIT_COUNT;{if((sr=read_sr(flash))<elseif(!(sr&SR_WIP))return0;/*REVISITsometimes wouldbebest}printk("in(%s):count=%d\n",countreturn}SetwriteenablelatchwithWriteEnableReturnsnegativeiferrorstaticinlineintwrite_enable(structm25p10a*flash{flash->cmd[0]=returnspi_write(flash->spi,flash->cmd,1}ErasethewholeflashReturns0ifsuccessful,non-zerostaticinterase_chip(structm25p10a*flash{/*Waituntilfinishedpreviouswritecommand.*/if(wait_till_ready(flash))return-/*Sendwriteenable,thenerasecommands.*/write_enable(flash);flash->cmd[0]=returnspi_write(flash->spi,flash->cmd,1}Readanaddressrangefromtheflashchip.Theaddressmaybeanysizeprovideditiswithinthephysicalstaticintm25p10a_read(structm25p10a*flash,loff_tfrom,size_tlen,char*buf){intr_count=0,flash->cmd[0]=CMD_READ_BYTES;flash->cmd[1]=from>>16;flash->cmd[2]=from>>8;flash->cmd[3]=from;#ifstructspi_transferst[2];structspi_messagemsg;spi_message_init(&msg);memset(st,0,sizeof(st));flash->cmd[0]=CMD_READ_BYTES;flash->cmd[1]=from>>16;flash->cmd[2]=from>>8;flash->cmd[3]=from;st[0].tx_buf=flash->cmd;st[0].len=CMD_SZ;spi_message_add_tail(&st[0],&msgst[1].rx_buf=buf;st[1].len=len;spi_message_add_tail(&st[1],&msg);mutex_lock(&flash->lock);/*Waituntilfinishedpreviouswritecommand.*/if(wait_till_ready(flash)){mutex_unlock(&flash->lock);return-1;}spi_sync(flash->spi,&msg);r_count=msg.actual_length-CMD_SZ;printk("in(%s):read%dbytes\n",for(i=0;i<r_count;i++){printk("0x%02x\n",buf[i]

func,r_count}mutex_unlock(&flash->lockreturn}Writeanaddressrangetotheflashchip.DatamustbewrittenFLASH_PAGE_SIZEchunks.Theaddressrangemaybeanysizeitiswithinthephysicalstaticintm25p10a_write(structm25p10a*flash,loff_tto,size_tlen,constchar*buf){intw_count=0,i,page_offset;structspi_transferst[2];structspi_messagemsg;#ifif(wait_till_ready(flash)){ mutex_unlock(&flash->lock);return-}write_enable(flashspi_message_init(&msg);memset(st,0,sizeof(st));flash->cmd[0]=CMD_PAGE_PROGRAM;flash->cmd[1]=to>>16;flash->cmd[2]=to>>8;flash->cmd[3]=to;st[0].tx_buf=flash->cmd;st[0].len=CMD_SZ;spi_message_add_tail(&st[0],&msgst[1].tx_buf=buf;st[1].len=len;spi_message_add_tail(&st[1],&msg);mutex_lock(&flash->lock);/*getoffsetaddressinsideapage*/page_offset=to%FLASH_PAGE_SIZE;/*doallthebytesfitontoonepage?if(page_offset+len<=FLASH_PAGE_SIZE){ st[1].len=len;printk("%d,cmd=%d\n",st[1].len,*(char{spi_sync(flash->spi,&msg}w_count=msg.actual_length-}else{//}printk("in(%s):write%dbytestoflashintotal\n",mutex_unlock(&flash->lock);return}

func,w_countstaticintcheck_id(structm25p10a*flash{charbuf[10]=flash->cmd[0]=spi_write_then_read(flash->spi,flash->cmd,1,buf,3);printk("ManufactureID:0x%x\n",buf[0]);printk("DeviceID:0x%x\n",buf[1]|buf[2]<<8);returnbuf[2]<<16|buf[1]<<8|buf[0];}staticintm25p10a_probe(structspi_device{intret=structm25p10a*flash;charbuf[256];printk("%swas flash=kzalloc(sizeof(structm25p10a),GFP_KERNEL);if(!flash){return-}flash->spi=spi;mutex_init(&flash->lock);/*saveflashasdriver'sprivatedata*/spi_set_drvdata(spi,flash);check_id(flash #ifreterase_chip(flash);//擦除if(ret<0){printk("erasetheentirelychipfailed\n"}printk("erasethewholechipdone\n");memset(buf,0x7,256);m25p10a_write(flash,0,20buf);/020memset(buf,0,256m25p10a_rea