/* * Blackfin On-Chip Two Wire Interface Driver * * Copyright 2005-2007 Analog Devices Inc. * * Enter bugs at http://blackfin.uclinux.org/ * * Licensed under the GPL-2 or later. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/i2c.h> #include <linux/slab.h> #include <linux/io.h> #include <linux/mm.h> #include <linux/timer.h> #include <linux/spinlock.h> #include <linux/completion.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/delay.h> #include <asm/blackfin.h> #include <asm/portmux.h> #include <asm/irq.h> #include <asm/bfin_twi.h> /* SMBus mode*/ #define TWI_I2C_MODE_STANDARD 1 #define TWI_I2C_MODE_STANDARDSUB 2 #define TWI_I2C_MODE_COMBINED 3 #define TWI_I2C_MODE_REPEAT 4 static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, unsigned short twi_int_status) { unsigned short mast_stat = read_MASTER_STAT(iface); if (twi_int_status & XMTSERV) { /* Transmit next data */ if (iface->writeNum > 0) { SSYNC(); write_XMT_DATA8(iface, *(iface->transPtr++)); iface->writeNum--; } /* start receive immediately after complete sending in * combine mode. */ else if (iface->cur_mode == TWI_I2C_MODE_COMBINED) write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MDIR); else if (iface->manual_stop) write_MASTER_CTL(iface, read_MASTER_CTL(iface) | STOP); else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && iface->cur_msg + 1 < iface->msg_num) { if (iface->pmsg[iface->cur_msg + 1].flags & I2C_M_RD) write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MDIR); else write_MASTER_CTL(iface, read_MASTER_CTL(iface) & ~MDIR); } } if (twi_int_status & RCVSERV) { if (iface->readNum > 0) { /* Receive next data */ *(iface->transPtr) = read_RCV_DATA8(iface); if (iface->cur_mode == TWI_I2C_MODE_COMBINED) { /* Change combine mode into sub mode after * read first data. */ iface->cur_mode = TWI_I2C_MODE_STANDARDSUB; /* Get read number from first byte in block * combine mode. */ if (iface->readNum == 1 && iface->manual_stop) iface->readNum = *iface->transPtr + 1; } iface->transPtr++; iface->readNum--; } if (iface->readNum == 0) { if (iface->manual_stop) { /* Temporary workaround to avoid possible bus stall - * Flush FIFO before issuing the STOP condition */ read_RCV_DATA16(iface); write_MASTER_CTL(iface, read_MASTER_CTL(iface) | STOP); } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && iface->cur_msg + 1 < iface->msg_num) { if (iface->pmsg[iface->cur_msg + 1].flags & I2C_M_RD) write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MDIR); else write_MASTER_CTL(iface, read_MASTER_CTL(iface) & ~MDIR); } } } if (twi_int_status & MERR) { write_INT_MASK(iface, 0); write_MASTER_STAT(iface, 0x3e); write_MASTER_CTL(iface, 0); iface->result = -EIO; if (mast_stat & LOSTARB) dev_dbg(&iface->adap.dev, "Lost Arbitration\n"); if (mast_stat & ANAK) dev_dbg(&iface->adap.dev, "Address Not Acknowledged\n"); if (mast_stat & DNAK) dev_dbg(&iface->adap.dev, "Data Not Acknowledged\n"); if (mast_stat & BUFRDERR) dev_dbg(&iface->adap.dev, "Buffer Read Error\n"); if (mast_stat & BUFWRERR) dev_dbg(&iface->adap.dev, "Buffer Write Error\n"); /* Faulty slave devices, may drive SDA low after a transfer * finishes. To release the bus this code generates up to 9 * extra clocks until SDA is released. */ if (read_MASTER_STAT(iface) & SDASEN) { int cnt = 9; do { write_MASTER_CTL(iface, SCLOVR); udelay(6); write_MASTER_CTL(iface, 0); udelay(6); } while ((read_MASTER_STAT(iface) & SDASEN) && cnt--); write_MASTER_CTL(iface, SDAOVR | SCLOVR); udelay(6); write_MASTER_CTL(iface, SDAOVR); udelay(6); write_MASTER_CTL(iface, 0); } /* If it is a quick transfer, only address without data, * not an err, return 1. */ if (iface->cur_mode == TWI_I2C_MODE_STANDARD && iface->transPtr == NULL && (twi_int_status & MCOMP) && (mast_stat & DNAK)) iface->result = 1; complete(&iface->complete); return; } if (twi_int_status & MCOMP) { if (twi_int_status & (XMTSERV | RCVSERV) && (read_MASTER_CTL(iface) & MEN) == 0 && (iface->cur_mode == TWI_I2C_MODE_REPEAT || iface->cur_mode == TWI_I2C_MODE_COMBINED)) { iface->result = -1; write_INT_MASK(iface, 0); write_MASTER_CTL(iface, 0); } else if (iface->cur_mode == TWI_I2C_MODE_COMBINED) { if (iface->readNum == 0) { /* set the read number to 1 and ask for manual * stop in block combine mode */ iface->readNum = 1; iface->manual_stop = 1; write_MASTER_CTL(iface, read_MASTER_CTL(iface) | (0xff << 6)); } else { /* set the readd number in other * combine mode. */ write_MASTER_CTL(iface, (read_MASTER_CTL(iface) & (~(0xff << 6))) | (iface->readNum << 6)); } /* remove restart bit and enable master receive */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) & ~RSTART); } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && iface->cur_msg + 1 < iface->msg_num) { iface->cur_msg++; iface->transPtr = iface->pmsg[iface->cur_msg].buf; iface->writeNum = iface->readNum = iface->pmsg[iface->cur_msg].len; /* Set Transmit device address */ write_MASTER_ADDR(iface, iface->pmsg[iface->cur_msg].addr); if (iface->pmsg[iface->cur_msg].flags & I2C_M_RD) iface->read_write = I2C_SMBUS_READ; else { iface->read_write = I2C_SMBUS_WRITE; /* Transmit first data */ if (iface->writeNum > 0) { write_XMT_DATA8(iface, *(iface->transPtr++)); iface->writeNum--; } } if (iface->pmsg[iface->cur_msg].len <= 255) { write_MASTER_CTL(iface, (read_MASTER_CTL(iface) & (~(0xff << 6))) | (iface->pmsg[iface->cur_msg].len << 6)); iface->manual_stop = 0; } else { write_MASTER_CTL(iface, (read_MASTER_CTL(iface) | (0xff << 6))); iface->manual_stop = 1; } /* remove restart bit before last message */ if (iface->cur_msg + 1 == iface->msg_num) write_MASTER_CTL(iface, read_MASTER_CTL(iface) & ~RSTART); } else { iface->result = 1; write_INT_MASK(iface, 0); write_MASTER_CTL(iface, 0); } complete(&iface->complete); } } /* Interrupt handler */ static irqreturn_t bfin_twi_interrupt_entry(int irq, void *dev_id) { struct bfin_twi_iface *iface = dev_id; unsigned long flags; unsigned short twi_int_status; spin_lock_irqsave(&iface->lock, flags); while (1) { twi_int_status = read_INT_STAT(iface); if (!twi_int_status) break; /* Clear interrupt status */ write_INT_STAT(iface, twi_int_status); bfin_twi_handle_interrupt(iface, twi_int_status); SSYNC(); } spin_unlock_irqrestore(&iface->lock, flags); return IRQ_HANDLED; } /* * One i2c master transfer */ static int bfin_twi_do_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct bfin_twi_iface *iface = adap->algo_data; struct i2c_msg *pmsg; int rc = 0; if (!(read_CONTROL(iface) & TWI_ENA)) return -ENXIO; if (read_MASTER_STAT(iface) & BUSBUSY) return -EAGAIN; iface->pmsg = msgs; iface->msg_num = num; iface->cur_msg = 0; pmsg = &msgs[0]; if (pmsg->flags & I2C_M_TEN) { dev_err(&adap->dev, "10 bits addr not supported!\n"); return -EINVAL; } if (iface->msg_num > 1) iface->cur_mode = TWI_I2C_MODE_REPEAT; iface->manual_stop = 0; iface->transPtr = pmsg->buf; iface->writeNum = iface->readNum = pmsg->len; iface->result = 0; init_completion(&(iface->complete)); /* Set Transmit device address */ write_MASTER_ADDR(iface, pmsg->addr); /* FIFO Initiation. Data in FIFO should be * discarded before start a new operation. */ write_FIFO_CTL(iface, 0x3); SSYNC(); write_FIFO_CTL(iface, 0); SSYNC(); if (pmsg->flags & I2C_M_RD) iface->read_write = I2C_SMBUS_READ; else { iface->read_write = I2C_SMBUS_WRITE; /* Transmit first data */ if (iface->writeNum > 0) { write_XMT_DATA8(iface, *(iface->transPtr++)); iface->writeNum--; SSYNC(); } } /* clear int stat */ write_INT_STAT(iface, MERR | MCOMP | XMTSERV | RCVSERV); /* Interrupt mask . Enable XMT, RCV interrupt */ write_INT_MASK(iface, MCOMP | MERR | RCVSERV | XMTSERV); SSYNC(); if (pmsg->len <= 255) write_MASTER_CTL(iface, pmsg->len << 6); else { write_MASTER_CTL(iface, 0xff << 6); iface->manual_stop = 1; } /* Master enable */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN | (iface->msg_num > 1 ? RSTART : 0) | ((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) | ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ > 100) ? FAST : 0)); SSYNC(); while (!iface->result) { if (!wait_for_completion_timeout(&iface->complete, adap->timeout)) { iface->result = -1; dev_err(&adap->dev, "master transfer timeout\n"); } } if (iface->result == 1) rc = iface->cur_msg + 1; else rc = iface->result; return rc; } /* * Generic i2c master transfer entrypoint */ static int bfin_twi_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { return bfin_twi_do_master_xfer(adap, msgs, num); } /* * One I2C SMBus transfer */ int bfin_twi_do_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags, char read_write, u8 command, int size, union i2c_smbus_data *data) { struct bfin_twi_iface *iface = adap->algo_data; int rc = 0; if (!(read_CONTROL(iface) & TWI_ENA)) return -ENXIO; if (read_MASTER_STAT(iface) & BUSBUSY) return -EAGAIN; iface->writeNum = 0; iface->readNum = 0; /* Prepare datas & select mode */ switch (size) { case I2C_SMBUS_QUICK: iface->transPtr = NULL; iface->cur_mode = TWI_I2C_MODE_STANDARD; break; case I2C_SMBUS_BYTE: if (data == NULL) iface->transPtr = NULL; else { if (read_write == I2C_SMBUS_READ) iface->readNum = 1; else iface->writeNum = 1; iface->transPtr = &data->byte; } iface->cur_mode = TWI_I2C_MODE_STANDARD; break; case I2C_SMBUS_BYTE_DATA: if (read_write == I2C_SMBUS_READ) { iface->readNum = 1; iface->cur_mode = TWI_I2C_MODE_COMBINED; } else { iface->writeNum = 1; iface->cur_mode = TWI_I2C_MODE_STANDARDSUB; } iface->transPtr = &data->byte; break; case I2C_SMBUS_WORD_DATA: if (read_write == I2C_SMBUS_READ) { iface->readNum = 2; iface->cur_mode = TWI_I2C_MODE_COMBINED; } else { iface->writeNum = 2; iface->cur_mode = TWI_I2C_MODE_STANDARDSUB; } iface->transPtr = (u8 *)&data->word; break; case I2C_SMBUS_PROC_CALL: iface->writeNum = 2; iface->readNum = 2; iface->cur_mode = TWI_I2C_MODE_COMBINED; iface->transPtr = (u8 *)&data->word; break; case I2C_SMBUS_BLOCK_DATA: if (read_write == I2C_SMBUS_READ) { iface->readNum = 0; iface->cur_mode = TWI_I2C_MODE_COMBINED; } else { iface->writeNum = data->block[0] + 1; iface->cur_mode = TWI_I2C_MODE_STANDARDSUB; } iface->transPtr = data->block; break; case I2C_SMBUS_I2C_BLOCK_DATA: if (read_write == I2C_SMBUS_READ) { iface->readNum = data->block[0]; iface->cur_mode = TWI_I2C_MODE_COMBINED; } else { iface->writeNum = data->block[0]; iface->cur_mode = TWI_I2C_MODE_STANDARDSUB; } iface->transPtr = (u8 *)&data->block[1]; break; default: return -1; } iface->result = 0; iface->manual_stop = 0; iface->read_write = read_write; iface->command = command; init_completion(&(iface->complete)); /* FIFO Initiation. Data in FIFO should be discarded before * start a new operation. */ write_FIFO_CTL(iface, 0x3); SSYNC(); write_FIFO_CTL(iface, 0); /* clear int stat */ write_INT_STAT(iface, MERR | MCOMP | XMTSERV | RCVSERV); /* Set Transmit device address */ write_MASTER_ADDR(iface, addr); SSYNC(); switch (iface->cur_mode) { case TWI_I2C_MODE_STANDARDSUB: write_XMT_DATA8(iface, iface->command); write_INT_MASK(iface, MCOMP | MERR | ((iface->read_write == I2C_SMBUS_READ) ? RCVSERV : XMTSERV)); SSYNC(); if (iface->writeNum + 1 <= 255) write_MASTER_CTL(iface, (iface->writeNum + 1) << 6); else { write_MASTER_CTL(iface, 0xff << 6); iface->manual_stop = 1; } /* Master enable */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN | ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0)); break; case TWI_I2C_MODE_COMBINED: write_XMT_DATA8(iface, iface->command); write_INT_MASK(iface, MCOMP | MERR | RCVSERV | XMTSERV); SSYNC(); if (iface->writeNum > 0) write_MASTER_CTL(iface, (iface->writeNum + 1) << 6); else write_MASTER_CTL(iface, 0x1 << 6); /* Master enable */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN | RSTART | ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0)); break; default: write_MASTER_CTL(iface, 0); if (size != I2C_SMBUS_QUICK) { /* Don't access xmit data register when this is a * read operation. */ if (iface->read_write != I2C_SMBUS_READ) { if (iface->writeNum > 0) { write_XMT_DATA8(iface, *(iface->transPtr++)); if (iface->writeNum <= 255) write_MASTER_CTL(iface, iface->writeNum << 6); else { write_MASTER_CTL(iface, 0xff << 6); iface->manual_stop = 1; } iface->writeNum--; } else { write_XMT_DATA8(iface, iface->command); write_MASTER_CTL(iface, 1 << 6); } } else { if (iface->readNum > 0 && iface->readNum <= 255) write_MASTER_CTL(iface, iface->readNum << 6); else if (iface->readNum > 255) { write_MASTER_CTL(iface, 0xff << 6); iface->manual_stop = 1; } else break; } } write_INT_MASK(iface, MCOMP | MERR | ((iface->read_write == I2C_SMBUS_READ) ? RCVSERV : XMTSERV)); SSYNC(); /* Master enable */ write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN | ((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) | ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ > 100) ? FAST : 0)); break; } SSYNC(); while (!iface->result) { if (!wait_for_completion_timeout(&iface->complete, adap->timeout)) { iface->result = -1; dev_err(&adap->dev, "smbus transfer timeout\n"); } } rc = (iface->result >= 0) ? 0 : -1; return rc; } /* * Generic I2C SMBus transfer entrypoint */ int bfin_twi_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags, char read_write, u8 command, int size, union i2c_smbus_data *data) { return bfin_twi_do_smbus_xfer(adap, addr, flags, read_write, command, size, data); } /* * Return what the adapter supports */ static u32 bfin_twi_functionality(struct i2c_adapter *adap) { return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_I2C_BLOCK; } static struct i2c_algorithm bfin_twi_algorithm = { .master_xfer = bfin_twi_master_xfer, .smbus_xfer = bfin_twi_smbus_xfer, .functionality = bfin_twi_functionality, }; static int i2c_bfin_twi_suspend(struct device *dev) { struct bfin_twi_iface *iface = dev_get_drvdata(dev); iface->saved_clkdiv = read_CLKDIV(iface); iface->saved_control = read_CONTROL(iface); free_irq(iface->irq, iface); /* Disable TWI */ write_CONTROL(iface, iface->saved_control & ~TWI_ENA); return 0; } static int i2c_bfin_twi_resume(struct device *dev) { struct bfin_twi_iface *iface = dev_get_drvdata(dev); int rc = request_irq(iface->irq, bfin_twi_interrupt_entry, 0, to_platform_device(dev)->name, iface); if (rc) { dev_err(dev, "Can't get IRQ %d !\n", iface->irq); return -ENODEV; } /* Resume TWI interface clock as specified */ write_CLKDIV(iface, iface->saved_clkdiv); /* Resume TWI */ write_CONTROL(iface, iface->saved_control); return 0; } static SIMPLE_DEV_PM_OPS(i2c_bfin_twi_pm, i2c_bfin_twi_suspend, i2c_bfin_twi_resume); static int i2c_bfin_twi_probe(struct platform_device *pdev) { struct bfin_twi_iface *iface; struct i2c_adapter *p_adap; struct resource *res; int rc; unsigned int clkhilow; iface = kzalloc(sizeof(struct bfin_twi_iface), GFP_KERNEL); if (!iface) { dev_err(&pdev->dev, "Cannot allocate memory\n"); rc = -ENOMEM; goto out_error_nomem; } spin_lock_init(&(iface->lock)); /* Find and map our resources */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n"); rc = -ENOENT; goto out_error_get_res; } iface->regs_base = ioremap(res->start, resource_size(res)); if (iface->regs_base == NULL) { dev_err(&pdev->dev, "Cannot map IO\n"); rc = -ENXIO; goto out_error_ioremap; } iface->irq = platform_get_irq(pdev, 0); if (iface->irq < 0) { dev_err(&pdev->dev, "No IRQ specified\n"); rc = -ENOENT; goto out_error_no_irq; } p_adap = &iface->adap; p_adap->nr = pdev->id; strlcpy(p_adap->name, pdev->name, sizeof(p_adap->name)); p_adap->algo = &bfin_twi_algorithm; p_adap->algo_data = iface; p_adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; p_adap->dev.parent = &pdev->dev; p_adap->timeout = 5 * HZ; p_adap->retries = 3; rc = peripheral_request_list((unsigned short *)pdev->dev.platform_data, "i2c-bfin-twi"); if (rc) { dev_err(&pdev->dev, "Can't setup pin mux!\n"); goto out_error_pin_mux; } rc = request_irq(iface->irq, bfin_twi_interrupt_entry, 0, pdev->name, iface); if (rc) { dev_err(&pdev->dev, "Can't get IRQ %d !\n", iface->irq); rc = -ENODEV; goto out_error_req_irq; } /* Set TWI internal clock as 10MHz */ write_CONTROL(iface, ((get_sclk() / 1000 / 1000 + 5) / 10) & 0x7F); /* * We will not end up with a CLKDIV=0 because no one will specify * 20kHz SCL or less in Kconfig now. (5 * 1000 / 20 = 250) */ clkhilow = ((10 * 1000 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ) + 1) / 2; /* Set Twi interface clock as specified */ write_CLKDIV(iface, (clkhilow << 8) | clkhilow); /* Enable TWI */ write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA); SSYNC(); rc = i2c_add_numbered_adapter(p_adap); if (rc < 0) { dev_err(&pdev->dev, "Can't add i2c adapter!\n"); goto out_error_add_adapter; } platform_set_drvdata(pdev, iface); dev_info(&pdev->dev, "Blackfin BF5xx on-chip I2C TWI Contoller, " "regs_base@%p\n", iface->regs_base); return 0; out_error_add_adapter: free_irq(iface->irq, iface); out_error_req_irq: out_error_no_irq: peripheral_free_list((unsigned short *)pdev->dev.platform_data); out_error_pin_mux: iounmap(iface->regs_base); out_error_ioremap: out_error_get_res: kfree(iface); out_error_nomem: return rc; } static int i2c_bfin_twi_remove(struct platform_device *pdev) { struct bfin_twi_iface *iface = platform_get_drvdata(pdev); i2c_del_adapter(&(iface->adap)); free_irq(iface->irq, iface); peripheral_free_list((unsigned short *)pdev->dev.platform_data); iounmap(iface->regs_base); kfree(iface); return 0; } static struct platform_driver i2c_bfin_twi_driver = { .probe = i2c_bfin_twi_probe, .remove = i2c_bfin_twi_remove, .driver = { .name = "i2c-bfin-twi", .owner = THIS_MODULE, .pm = &i2c_bfin_twi_pm, }, }; static int __init i2c_bfin_twi_init(void) { return platform_driver_register(&i2c_bfin_twi_driver); } static void __exit i2c_bfin_twi_exit(void) { platform_driver_unregister(&i2c_bfin_twi_driver); } subsys_initcall(i2c_bfin_twi_init); module_exit(i2c_bfin_twi_exit); MODULE_AUTHOR("Bryan Wu, Sonic Zhang"); MODULE_DESCRIPTION("Blackfin BF5xx on-chip I2C TWI Contoller Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:i2c-bfin-twi");