设备树学习之(十)spi flash
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开发板:tiny4412SDK + S702 + 4GB Flash
要移植的内核版本:Linux-4.4.0 (支持device tree)
u-boot版本:友善之臂自带的 U-Boot 2010.12
busybox版本:busybox 1.25
目标:
驱动外接的8M的 spi flash,注册为块设备。
设备树:
&spi_0 { status = "okay"; cs-gpios = <&gpb 1 GPIO_ACTIVE_HIGH>; spi_flash@0 { compatible = "tiny4412,spi_flash"; spi-max-frequency = <10000000>; reg = <0>; controller-data { samsung,spi-feedback-delay = <0>; }; };};
这里指定的 reg = <0> 表示的该 spi 设备引用第一个 cs-gpios
spi-max-frequency = <10000000>;表示最大速率
代码:
#include <linux/clk.h>#include <linux/delay.h>#include <linux/firmware.h>#include <linux/gpio.h>#include <linux/i2c.h>#include <linux/init.h>#include <linux/media.h>#include <linux/module.h>#include <linux/of_gpio.h>#include <linux/regulator/consumer.h>#include <linux/sizes.h>#include <linux/slab.h>#include <linux/spi/spi.h>#include <linux/videodev2.h>#include <media/media-entity.h>#include <media/v4l2-ctrls.h>#include <media/v4l2-device.h>#include <media/v4l2-subdev.h>#include <media/v4l2-mediabus.h>#include <media/s5c73m3.h>#include <media/v4l2-of.h>#include <linux/mtd/mtd.h>/* 参考: * drivers\mtd\devices\mtdram.c * drivers/mtd/devices/m25p80.c */static struct spi_device *spi_flash;void SPIFlashReadID(int *pMID, int *pDID){ unsigned char tx_buf[4]; unsigned char rx_buf[2]; //printk("%s\n",__func__); tx_buf[0] = 0x90; tx_buf[1] = 0; tx_buf[2] = 0; tx_buf[3] = 0; spi_write_then_read(spi_flash, tx_buf, 4, rx_buf, 2); *pMID = rx_buf[0]; *pDID = rx_buf[1];}static void SPIFlashWriteEnable(int enable){ unsigned char val = enable ? 0x06 : 0x04; //printk("%s\n",__func__); spi_write(spi_flash, &val, 1);}static unsigned char SPIFlashReadStatusReg1(void){ unsigned char val; unsigned char cmd = 0x05; //printk("%s\n",__func__); spi_write_then_read(spi_flash, &cmd, 1, &val, 1); return val;}static unsigned char SPIFlashReadStatusReg2(void){ unsigned char val; unsigned char cmd = 0x35; //printk("%s\n",__func__); spi_write_then_read(spi_flash, &cmd, 1, &val, 1); return val;}static void SPIFlashWaitWhenBusy(void){ //printk("%s\n",__func__); while (SPIFlashReadStatusReg1() & 1) { /* 休眠一段时间 */ /* Sector erase time : 60ms * Page program time : 0.7ms * Write status reg time : 10ms */ set_current_state(TASK_INTERRUPTIBLE); schedule_timeout(HZ / 100); /* 休眠10MS后再次判断 */ }}static void SPIFlashWriteStatusReg(unsigned char reg1, unsigned char reg2){ unsigned char tx_buf[4]; //printk("%s\n",__func__); SPIFlashWriteEnable(1); tx_buf[0] = 0x01; tx_buf[1] = reg1; tx_buf[2] = reg2; spi_write(spi_flash, tx_buf, 3); SPIFlashWaitWhenBusy();}static void SPIFlashClearProtectForStatusReg(void){ unsigned char reg1, reg2; //printk("%s\n",__func__); reg1 = SPIFlashReadStatusReg1(); reg2 = SPIFlashReadStatusReg2(); reg1 &= ~(1 << 7); reg2 &= ~(1 << 0); SPIFlashWriteStatusReg(reg1, reg2);}static void SPIFlashClearProtectForData(void){ /* cmp=0,bp2,1,0=0b000 */ unsigned char reg1, reg2; //printk("%s\n",__func__); reg1 = SPIFlashReadStatusReg1(); reg2 = SPIFlashReadStatusReg2(); reg1 &= ~(7 << 2); reg2 &= ~(1 << 6); SPIFlashWriteStatusReg(reg1, reg2);}/* erase 4K */void SPIFlashEraseSector(unsigned int addr){ unsigned char tx_buf[4]; //printk("%s\n",__func__); tx_buf[0] = 0x20; tx_buf[1] = addr >> 16; tx_buf[2] = addr >> 8; tx_buf[3] = addr & 0xff; SPIFlashWriteEnable(1); spi_write(spi_flash, tx_buf, 4); SPIFlashWaitWhenBusy();}/* program */void SPIFlashProgram(unsigned int addr, unsigned char *buf, int len){ unsigned char tx_buf[4]; struct spi_transfer t[] = { { .tx_buf = tx_buf, .len = 4, }, { .tx_buf = buf, .len = len, }, }; struct spi_message m; //printk("%s\n",__func__); tx_buf[0] = 0x02; tx_buf[1] = addr >> 16; tx_buf[2] = addr >> 8; tx_buf[3] = addr & 0xff; SPIFlashWriteEnable(1); spi_message_init(&m); spi_message_add_tail(&t[0], &m); spi_message_add_tail(&t[1], &m); spi_sync(spi_flash, &m); SPIFlashWaitWhenBusy();}void SPIFlashRead(unsigned int addr, unsigned char *buf, int len){ /* spi_write_then_read规定了tx_cnt+rx_cnt < 32 * 所以对于大量数据的读取,不能使用该函数 */ unsigned char tx_buf[4]; struct spi_transfer t[] = { { .tx_buf = tx_buf, .len = 4, }, { .rx_buf = buf, .len = len, }, }; struct spi_message m; //printk("%s\n",__func__); tx_buf[0] = 0x03; tx_buf[1] = addr >> 16; tx_buf[2] = addr >> 8; tx_buf[3] = addr & 0xff; spi_message_init(&m); spi_message_add_tail(&t[0], &m); spi_message_add_tail(&t[1], &m); spi_sync(spi_flash, &m);}static void SPIFlashInit(void){ SPIFlashClearProtectForStatusReg(); SPIFlashClearProtectForData();}/* 构造注册一个mtd_info * mtd_device_register(master, parts, nr_parts) * *//* 首先: 构造注册spi_driver * 然后: 在spi_driver的probe函数里构造注册mtd_info */static struct mtd_info spi_flash_dev;static int spi_flash_erase(struct mtd_info *mtd, struct erase_info *instr){ unsigned int addr = instr->addr; unsigned int len = 0; //判断参数 if ((addr & (spi_flash_dev.erasesize - 1)) || (instr->len & (spi_flash_dev.erasesize - 1))) { printk("spi_flash_erase addr/len is not aligned %x %x\n",(unsigned int)instr->addr,(unsigned int)instr->len); return -EINVAL; } for (len = 0; len < instr->len; len += 4096) { SPIFlashEraseSector(addr); addr += 4096; } instr->state = MTD_ERASE_DONE; mtd_erase_callback(instr); return 0;}static int spi_flash_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf){ SPIFlashRead(from, buf, len); *retlen = len; return 0;}static int spi_flash_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf){ unsigned int addr = to; unsigned int wlen = 0; unsigned int i; //判断参数 if ((to & (spi_flash_dev.erasesize - 1))) { printk("spi_flash_write addr/len is not aligned %x %x\n",(unsigned int)to,(unsigned int)len); return -EINVAL; } if (len <= 256) { SPIFlashProgram(addr, (unsigned char *)buf, len); } else { for (i = 0; i < len / 256; i ++) { SPIFlashProgram(addr, (unsigned char *)buf, 256); addr += 256; buf += 256; } if (len % 256 != 0) { SPIFlashProgram(addr, (unsigned char *)buf, len % 256); } } *retlen = len; return 0;}static int spi_flash_probe(struct spi_device *spi){ int mid, did, ret; spi_flash = spi; spi->mode = SPI_MODE_0; ret = spi_setup(spi); if (ret < 0) { printk("spi_setup error\n"); } printk("%s\n",__func__); //s3c2410_gpio_cfgpin(spi->chip_select, S3C2410_GPIO_OUTPUT); SPIFlashInit(); SPIFlashReadID(&mid, &did); printk("SPI Flash ID: %02x %02x\n", mid, did); memset(&spi_flash_dev, 0, sizeof(spi_flash_dev)); //Setup the MTD structure spi_flash_dev.name = "spi_flash"; spi_flash_dev.type = MTD_NORFLASH; spi_flash_dev.flags = MTD_CAP_NORFLASH; spi_flash_dev.size = 0x800000; spi_flash_dev.writesize = 1; spi_flash_dev.writebufsize = 4096; spi_flash_dev.erasesize = 4096; spi_flash_dev.owner = THIS_MODULE; spi_flash_dev._erase = spi_flash_erase; spi_flash_dev._read = spi_flash_read; spi_flash_dev._write = spi_flash_write; mtd_device_register(&spi_flash_dev, NULL, 0); return 0;}static int spi_flash_remove(struct spi_device *spi){ mtd_device_unregister(&spi_flash_dev); return 0;}static const struct of_device_id spi_flash_ids[] = { { .compatible = "tiny4412,spi_flash" }, { }};static struct spi_driver spi_flash_drv ={ .driver = { .name = "spi_flash", }, .probe = spi_flash_probe, .remove = spi_flash_remove,};static int spi_flash_init(void){ printk("init\n"); return spi_register_driver(&spi_flash_drv);}static void spi_flash_exit(void){ spi_unregister_driver(&spi_flash_drv);}module_init(spi_flash_init);module_exit(spi_flash_exit);MODULE_LICENSE("GPL");
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