/* * Synopsys Designware I2C adapter driver (master only). * * Based on the TI DAVINCI I2C adapter driver. * * Copyright (C) 2006 Texas Instruments. * Copyright (C) 2007 MontaVista Software Inc. * Copyright (C) 2009 Provigent Ltd. * * ---------------------------------------------------------------------------- * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * ---------------------------------------------------------------------------- * */ #include #include #include #include #include #include #include #include #include #include #include /* * Registers offset */ #define DW_IC_CON 0x0 #define DW_IC_TAR 0x4 #define DW_IC_DATA_CMD 0x10 #define DW_IC_SS_SCL_HCNT 0x14 #define DW_IC_SS_SCL_LCNT 0x18 #define DW_IC_FS_SCL_HCNT 0x1c #define DW_IC_FS_SCL_LCNT 0x20 #define DW_IC_INTR_STAT 0x2c #define DW_IC_INTR_MASK 0x30 #define DW_IC_RAW_INTR_STAT 0x34 #define DW_IC_CLR_INTR 0x40 #define DW_IC_CLR_RX_UNDER 0x44 #define DW_IC_CLR_RX_OVER 0x48 #define DW_IC_CLR_TX_OVER 0x4c #define DW_IC_CLR_RD_REQ 0x50 #define DW_IC_CLR_TX_ABRT 0x54 #define DW_IC_CLR_RX_DONE 0x58 #define DW_IC_CLR_ACTIVITY 0x5c #define DW_IC_CLR_STOP_DET 0x60 #define DW_IC_CLR_START_DET 0x64 #define DW_IC_CLR_GEN_CALL 0x68 #define DW_IC_ENABLE 0x6c #define DW_IC_STATUS 0x70 #define DW_IC_TXFLR 0x74 #define DW_IC_RXFLR 0x78 #define DW_IC_COMP_PARAM_1 0xf4 #define DW_IC_TX_ABRT_SOURCE 0x80 #define DW_IC_CON_MASTER 0x1 #define DW_IC_CON_SPEED_STD 0x2 #define DW_IC_CON_SPEED_FAST 0x4 #define DW_IC_CON_10BITADDR_MASTER 0x10 #define DW_IC_CON_RESTART_EN 0x20 #define DW_IC_CON_SLAVE_DISABLE 0x40 #define DW_IC_INTR_RX_UNDER 0x001 #define DW_IC_INTR_RX_OVER 0x002 #define DW_IC_INTR_RX_FULL 0x004 #define DW_IC_INTR_TX_OVER 0x008 #define DW_IC_INTR_TX_EMPTY 0x010 #define DW_IC_INTR_RD_REQ 0x020 #define DW_IC_INTR_TX_ABRT 0x040 #define DW_IC_INTR_RX_DONE 0x080 #define DW_IC_INTR_ACTIVITY 0x100 #define DW_IC_INTR_STOP_DET 0x200 #define DW_IC_INTR_START_DET 0x400 #define DW_IC_INTR_GEN_CALL 0x800 #define DW_IC_STATUS_ACTIVITY 0x1 #define DW_IC_ERR_TX_ABRT 0x1 /* * status codes */ #define STATUS_IDLE 0x0 #define STATUS_WRITE_IN_PROGRESS 0x1 #define STATUS_READ_IN_PROGRESS 0x2 #define TIMEOUT 20 /* ms */ /* * hardware abort codes from the DW_IC_TX_ABRT_SOURCE register * * only expected abort codes are listed here * refer to the datasheet for the full list */ #define ABRT_7B_ADDR_NOACK 0 #define ABRT_10ADDR1_NOACK 1 #define ABRT_10ADDR2_NOACK 2 #define ABRT_TXDATA_NOACK 3 #define ABRT_GCALL_NOACK 4 #define ABRT_GCALL_READ 5 #define ABRT_SBYTE_ACKDET 7 #define ABRT_SBYTE_NORSTRT 9 #define ABRT_10B_RD_NORSTRT 10 #define ARB_MASTER_DIS 11 #define ARB_LOST 12 static char *abort_sources[] = { [ABRT_7B_ADDR_NOACK] = "slave address not acknowledged (7bit mode)", [ABRT_10ADDR1_NOACK] = "first address byte not acknowledged (10bit mode)", [ABRT_10ADDR2_NOACK] = "second address byte not acknowledged (10bit mode)", [ABRT_TXDATA_NOACK] = "data not acknowledged", [ABRT_GCALL_NOACK] = "no acknowledgement for a general call", [ABRT_GCALL_READ] = "read after general call", [ABRT_SBYTE_ACKDET] = "start byte acknowledged", [ABRT_SBYTE_NORSTRT] = "trying to send start byte when restart is disabled", [ABRT_10B_RD_NORSTRT] = "trying to read when restart is disabled (10bit mode)", [ARB_MASTER_DIS] = "trying to use disabled adapter", [ARB_LOST] = "lost arbitration", }; /** * struct dw_i2c_dev - private i2c-designware data * @dev: driver model device node * @base: IO registers pointer * @cmd_complete: tx completion indicator * @lock: protect this struct and IO registers * @clk: input reference clock * @cmd_err: run time hadware error code * @msgs: points to an array of messages currently being transfered * @msgs_num: the number of elements in msgs * @msg_write_idx: the element index of the current tx message in the msgs * array * @tx_buf_len: the length of the current tx buffer * @tx_buf: the current tx buffer * @msg_read_idx: the element index of the current rx message in the msgs * array * @rx_buf_len: the length of the current rx buffer * @rx_buf: the current rx buffer * @msg_err: error status of the current transfer * @status: i2c master status, one of STATUS_* * @abort_source: copy of the TX_ABRT_SOURCE register * @irq: interrupt number for the i2c master * @adapter: i2c subsystem adapter node * @tx_fifo_depth: depth of the hardware tx fifo * @rx_fifo_depth: depth of the hardware rx fifo */ struct dw_i2c_dev { struct device *dev; void __iomem *base; struct completion cmd_complete; struct mutex lock; struct clk *clk; int cmd_err; struct i2c_msg *msgs; int msgs_num; int msg_write_idx; u32 tx_buf_len; u8 *tx_buf; int msg_read_idx; u32 rx_buf_len; u8 *rx_buf; int msg_err; unsigned int status; u32 abort_source; int irq; struct i2c_adapter adapter; unsigned int tx_fifo_depth; unsigned int rx_fifo_depth; }; static u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset) { /* * DesignWare I2C core doesn't seem to have solid strategy to meet * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec * will result in violation of the tHD;STA spec. */ if (cond) /* * Conditional expression: * * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH * * This is based on the DW manuals, and represents an ideal * configuration. The resulting I2C bus speed will be * faster than any of the others. * * If your hardware is free from tHD;STA issue, try this one. */ return (ic_clk * tSYMBOL + 5000) / 10000 - 8 + offset; else /* * Conditional expression: * * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf) * * This is just experimental rule; the tHD;STA period turned * out to be proportinal to (_HCNT + 3). With this setting, * we could meet both tHIGH and tHD;STA timing specs. * * If unsure, you'd better to take this alternative. * * The reason why we need to take into account "tf" here, * is the same as described in i2c_dw_scl_lcnt(). */ return (ic_clk * (tSYMBOL + tf) + 5000) / 10000 - 3 + offset; } static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset) { /* * Conditional expression: * * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf) * * DW I2C core starts counting the SCL CNTs for the LOW period * of the SCL clock (tLOW) as soon as it pulls the SCL line. * In order to meet the tLOW timing spec, we need to take into * account the fall time of SCL signal (tf). Default tf value * should be 0.3 us, for safety. */ return ((ic_clk * (tLOW + tf) + 5000) / 10000) - 1 + offset; } /** * i2c_dw_init() - initialize the designware i2c master hardware * @dev: device private data * * This functions configures and enables the I2C master. * This function is called during I2C init function, and in case of timeout at * run time. */ static void i2c_dw_init(struct dw_i2c_dev *dev) { u32 input_clock_khz = clk_get_rate(dev->clk) / 1000; u32 ic_con, hcnt, lcnt; /* Disable the adapter */ writel(0, dev->base + DW_IC_ENABLE); /* set standard and fast speed deviders for high/low periods */ /* Standard-mode */ hcnt = i2c_dw_scl_hcnt(input_clock_khz, 40, /* tHD;STA = tHIGH = 4.0 us */ 3, /* tf = 0.3 us */ 0, /* 0: DW default, 1: Ideal */ 0); /* No offset */ lcnt = i2c_dw_scl_lcnt(input_clock_khz, 47, /* tLOW = 4.7 us */ 3, /* tf = 0.3 us */ 0); /* No offset */ writel(hcnt, dev->base + DW_IC_SS_SCL_HCNT); writel(lcnt, dev->base + DW_IC_SS_SCL_LCNT); dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); /* Fast-mode */ hcnt = i2c_dw_scl_hcnt(input_clock_khz, 6, /* tHD;STA = tHIGH = 0.6 us */ 3, /* tf = 0.3 us */ 0, /* 0: DW default, 1: Ideal */ 0); /* No offset */ lcnt = i2c_dw_scl_lcnt(input_clock_khz, 13, /* tLOW = 1.3 us */ 3, /* tf = 0.3 us */ 0); /* No offset */ writel(hcnt, dev->base + DW_IC_FS_SCL_HCNT); writel(lcnt, dev->base + DW_IC_FS_SCL_LCNT); dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); /* configure the i2c master */ ic_con = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST; writel(ic_con, dev->base + DW_IC_CON); } /* * Waiting for bus not busy */ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) { int timeout = TIMEOUT; while (readl(dev->base + DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) { if (timeout <= 0) { dev_warn(dev->dev, "timeout waiting for bus ready\n"); return -ETIMEDOUT; } timeout--; mdelay(1); } return 0; } /* * Initiate low level master read/write transaction. * This function is called from i2c_dw_xfer when starting a transfer. * This function is also called from i2c_dw_isr to continue a transfer * that is longer than the size of the TX FIFO. */ static void i2c_dw_xfer_msg(struct dw_i2c_dev *dev) { struct i2c_msg *msgs = dev->msgs; u32 ic_con, intr_mask; int tx_limit = dev->tx_fifo_depth - readl(dev->base + DW_IC_TXFLR); int rx_limit = dev->rx_fifo_depth - readl(dev->base + DW_IC_RXFLR); u32 addr = msgs[dev->msg_write_idx].addr; u32 buf_len = dev->tx_buf_len; intr_mask = DW_IC_INTR_STOP_DET | DW_IC_INTR_TX_ABRT; if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) { /* Disable the adapter */ writel(0, dev->base + DW_IC_ENABLE); /* set the slave (target) address */ writel(msgs[dev->msg_write_idx].addr, dev->base + DW_IC_TAR); /* if the slave address is ten bit address, enable 10BITADDR */ ic_con = readl(dev->base + DW_IC_CON); if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) ic_con |= DW_IC_CON_10BITADDR_MASTER; else ic_con &= ~DW_IC_CON_10BITADDR_MASTER; writel(ic_con, dev->base + DW_IC_CON); /* Enable the adapter */ writel(1, dev->base + DW_IC_ENABLE); } for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) { /* if target address has changed, we need to * reprogram the target address in the i2c * adapter when we are done with this transfer */ if (msgs[dev->msg_write_idx].addr != addr) return; if (msgs[dev->msg_write_idx].len == 0) { dev_err(dev->dev, "%s: invalid message length\n", __func__); dev->msg_err = -EINVAL; return; } if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) { /* new i2c_msg */ dev->tx_buf = msgs[dev->msg_write_idx].buf; buf_len = msgs[dev->msg_write_idx].len; } while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) { if (msgs[dev->msg_write_idx].flags & I2C_M_RD) { writel(0x100, dev->base + DW_IC_DATA_CMD); rx_limit--; } else writel(*(dev->tx_buf++), dev->base + DW_IC_DATA_CMD); tx_limit--; buf_len--; } dev->tx_buf_len = buf_len; if (buf_len > 0) { /* more bytes to be written */ intr_mask |= DW_IC_INTR_TX_EMPTY; dev->status |= STATUS_WRITE_IN_PROGRESS; break; } else dev->status &= ~STATUS_WRITE_IN_PROGRESS; } writel(intr_mask, dev->base + DW_IC_INTR_MASK); } static void i2c_dw_read(struct dw_i2c_dev *dev) { struct i2c_msg *msgs = dev->msgs; u32 addr = msgs[dev->msg_read_idx].addr; int rx_valid = readl(dev->base + DW_IC_RXFLR); for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) { u32 len; u8 *buf; if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD)) continue; /* different i2c client, reprogram the i2c adapter */ if (msgs[dev->msg_read_idx].addr != addr) return; if (!(dev->status & STATUS_READ_IN_PROGRESS)) { len = msgs[dev->msg_read_idx].len; buf = msgs[dev->msg_read_idx].buf; } else { len = dev->rx_buf_len; buf = dev->rx_buf; } for (; len > 0 && rx_valid > 0; len--, rx_valid--) *buf++ = readl(dev->base + DW_IC_DATA_CMD); if (len > 0) { dev->status |= STATUS_READ_IN_PROGRESS; dev->rx_buf_len = len; dev->rx_buf = buf; return; } else dev->status &= ~STATUS_READ_IN_PROGRESS; } } /* * Prepare controller for a transaction and call i2c_dw_xfer_msg */ static int i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { struct dw_i2c_dev *dev = i2c_get_adapdata(adap); int ret; dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num); mutex_lock(&dev->lock); INIT_COMPLETION(dev->cmd_complete); dev->msgs = msgs; dev->msgs_num = num; dev->cmd_err = 0; dev->msg_write_idx = 0; dev->msg_read_idx = 0; dev->msg_err = 0; dev->status = STATUS_IDLE; ret = i2c_dw_wait_bus_not_busy(dev); if (ret < 0) goto done; /* start the transfers */ i2c_dw_xfer_msg(dev); /* wait for tx to complete */ ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ); if (ret == 0) { dev_err(dev->dev, "controller timed out\n"); i2c_dw_init(dev); ret = -ETIMEDOUT; goto done; } else if (ret < 0) goto done; if (dev->msg_err) { ret = dev->msg_err; goto done; } /* no error */ if (likely(!dev->cmd_err)) { /* Disable the adapter */ writel(0, dev->base + DW_IC_ENABLE); ret = num; goto done; } /* We have an error */ if (dev->cmd_err == DW_IC_ERR_TX_ABRT) { unsigned long abort_source = dev->abort_source; int i; for_each_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) { dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); } } ret = -EIO; done: mutex_unlock(&dev->lock); return ret; } static u32 i2c_dw_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR; } static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev) { u32 stat; /* * The IC_INTR_STAT register just indicates "enabled" interrupts. * Ths unmasked raw version of interrupt status bits are available * in the IC_RAW_INTR_STAT register. * * That is, * stat = readl(IC_INTR_STAT); * equals to, * stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK); * * The raw version might be useful for debugging purposes. */ stat = readl(dev->base + DW_IC_INTR_STAT); /* * Do not use the IC_CLR_INTR register to clear interrupts, or * you'll miss some interrupts, triggered during the period from * readl(IC_INTR_STAT) to readl(IC_CLR_INTR). * * Instead, use the separately-prepared IC_CLR_* registers. */ if (stat & DW_IC_INTR_RX_UNDER) readl(dev->base + DW_IC_CLR_RX_UNDER); if (stat & DW_IC_INTR_RX_OVER) readl(dev->base + DW_IC_CLR_RX_OVER); if (stat & DW_IC_INTR_TX_OVER) readl(dev->base + DW_IC_CLR_TX_OVER); if (stat & DW_IC_INTR_RD_REQ) readl(dev->base + DW_IC_CLR_RD_REQ); if (stat & DW_IC_INTR_TX_ABRT) { /* * The IC_TX_ABRT_SOURCE register is cleared whenever * the IC_CLR_TX_ABRT is read. Preserve it beforehand. */ dev->abort_source = readl(dev->base + DW_IC_TX_ABRT_SOURCE); readl(dev->base + DW_IC_CLR_TX_ABRT); } if (stat & DW_IC_INTR_RX_DONE) readl(dev->base + DW_IC_CLR_RX_DONE); if (stat & DW_IC_INTR_ACTIVITY) readl(dev->base + DW_IC_CLR_ACTIVITY); if (stat & DW_IC_INTR_STOP_DET) readl(dev->base + DW_IC_CLR_STOP_DET); if (stat & DW_IC_INTR_START_DET) readl(dev->base + DW_IC_CLR_START_DET); if (stat & DW_IC_INTR_GEN_CALL) readl(dev->base + DW_IC_CLR_GEN_CALL); return stat; } /* * Interrupt service routine. This gets called whenever an I2C interrupt * occurs. */ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id) { struct dw_i2c_dev *dev = dev_id; u32 stat; stat = i2c_dw_read_clear_intrbits(dev); dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat); if (stat & DW_IC_INTR_TX_ABRT) { dev->cmd_err |= DW_IC_ERR_TX_ABRT; dev->status = STATUS_IDLE; } if (stat & DW_IC_INTR_TX_EMPTY) { i2c_dw_read(dev); i2c_dw_xfer_msg(dev); } /* * No need to modify or disable the interrupt mask here. * i2c_dw_xfer_msg() will take care of it according to * the current transmit status. */ if (stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) complete(&dev->cmd_complete); return IRQ_HANDLED; } static struct i2c_algorithm i2c_dw_algo = { .master_xfer = i2c_dw_xfer, .functionality = i2c_dw_func, }; static int __devinit dw_i2c_probe(struct platform_device *pdev) { struct dw_i2c_dev *dev; struct i2c_adapter *adap; struct resource *mem, *ioarea; int irq, r; /* NOTE: driver uses the static register mapping */ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!mem) { dev_err(&pdev->dev, "no mem resource?\n"); return -EINVAL; } irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "no irq resource?\n"); return irq; /* -ENXIO */ } ioarea = request_mem_region(mem->start, resource_size(mem), pdev->name); if (!ioarea) { dev_err(&pdev->dev, "I2C region already claimed\n"); return -EBUSY; } dev = kzalloc(sizeof(struct dw_i2c_dev), GFP_KERNEL); if (!dev) { r = -ENOMEM; goto err_release_region; } init_completion(&dev->cmd_complete); mutex_init(&dev->lock); dev->dev = get_device(&pdev->dev); dev->irq = irq; platform_set_drvdata(pdev, dev); dev->clk = clk_get(&pdev->dev, NULL); if (IS_ERR(dev->clk)) { r = -ENODEV; goto err_free_mem; } clk_enable(dev->clk); dev->base = ioremap(mem->start, resource_size(mem)); if (dev->base == NULL) { dev_err(&pdev->dev, "failure mapping io resources\n"); r = -EBUSY; goto err_unuse_clocks; } { u32 param1 = readl(dev->base + DW_IC_COMP_PARAM_1); dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1; dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1; } i2c_dw_init(dev); writel(0, dev->base + DW_IC_INTR_MASK); /* disable IRQ */ r = request_irq(dev->irq, i2c_dw_isr, 0, pdev->name, dev); if (r) { dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq); goto err_iounmap; } adap = &dev->adapter; i2c_set_adapdata(adap, dev); adap->owner = THIS_MODULE; adap->class = I2C_CLASS_HWMON; strlcpy(adap->name, "Synopsys DesignWare I2C adapter", sizeof(adap->name)); adap->algo = &i2c_dw_algo; adap->dev.parent = &pdev->dev; adap->nr = pdev->id; r = i2c_add_numbered_adapter(adap); if (r) { dev_err(&pdev->dev, "failure adding adapter\n"); goto err_free_irq; } return 0; err_free_irq: free_irq(dev->irq, dev); err_iounmap: iounmap(dev->base); err_unuse_clocks: clk_disable(dev->clk); clk_put(dev->clk); dev->clk = NULL; err_free_mem: platform_set_drvdata(pdev, NULL); put_device(&pdev->dev); kfree(dev); err_release_region: release_mem_region(mem->start, resource_size(mem)); return r; } static int __devexit dw_i2c_remove(struct platform_device *pdev) { struct dw_i2c_dev *dev = platform_get_drvdata(pdev); struct resource *mem; platform_set_drvdata(pdev, NULL); i2c_del_adapter(&dev->adapter); put_device(&pdev->dev); clk_disable(dev->clk); clk_put(dev->clk); dev->clk = NULL; writel(0, dev->base + DW_IC_ENABLE); free_irq(dev->irq, dev); kfree(dev); mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); release_mem_region(mem->start, resource_size(mem)); return 0; } /* work with hotplug and coldplug */ MODULE_ALIAS("platform:i2c_designware"); static struct platform_driver dw_i2c_driver = { .remove = __devexit_p(dw_i2c_remove), .driver = { .name = "i2c_designware", .owner = THIS_MODULE, }, }; static int __init dw_i2c_init_driver(void) { return platform_driver_probe(&dw_i2c_driver, dw_i2c_probe); } module_init(dw_i2c_init_driver); static void __exit dw_i2c_exit_driver(void) { platform_driver_unregister(&dw_i2c_driver); } module_exit(dw_i2c_exit_driver); MODULE_AUTHOR("Baruch Siach "); MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter"); MODULE_LICENSE("GPL");