diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-designware-master.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-master.c | 672 |
1 files changed, 672 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c new file mode 100644 index 000000000000..418c233075d3 --- /dev/null +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -0,0 +1,672 @@ +/* + * 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. + * ---------------------------------------------------------------------------- + * + */ +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/pm_runtime.h> + +#include "i2c-designware-core.h" + +static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev) +{ + /* Configure Tx/Rx FIFO threshold levels */ + dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL); + dw_writel(dev, 0, DW_IC_RX_TL); + + /* Configure the I2C master */ + dw_writel(dev, dev->master_cfg, DW_IC_CON); +} + +/** + * 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 int i2c_dw_init_master(struct dw_i2c_dev *dev) +{ + u32 hcnt, lcnt; + u32 reg, comp_param1; + u32 sda_falling_time, scl_falling_time; + int ret; + + ret = i2c_dw_acquire_lock(dev); + if (ret) + return ret; + + reg = dw_readl(dev, DW_IC_COMP_TYPE); + if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) { + /* Configure register endianess access */ + dev->flags |= ACCESS_SWAP; + } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { + /* Configure register access mode 16bit */ + dev->flags |= ACCESS_16BIT; + } else if (reg != DW_IC_COMP_TYPE_VALUE) { + dev_err(dev->dev, + "Unknown Synopsys component type: 0x%08x\n", reg); + i2c_dw_release_lock(dev); + return -ENODEV; + } + + comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1); + + /* Disable the adapter */ + __i2c_dw_enable_and_wait(dev, false); + + /* Set standard and fast speed deviders for high/low periods */ + + sda_falling_time = dev->sda_falling_time ?: 300; /* ns */ + scl_falling_time = dev->scl_falling_time ?: 300; /* ns */ + + /* Set SCL timing parameters for standard-mode */ + if (dev->ss_hcnt && dev->ss_lcnt) { + hcnt = dev->ss_hcnt; + lcnt = dev->ss_lcnt; + } else { + hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev), + 4000, /* tHD;STA = tHIGH = 4.0 us */ + sda_falling_time, + 0, /* 0: DW default, 1: Ideal */ + 0); /* No offset */ + lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev), + 4700, /* tLOW = 4.7 us */ + scl_falling_time, + 0); /* No offset */ + } + dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT); + dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT); + dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); + + /* Set SCL timing parameters for fast-mode or fast-mode plus */ + if ((dev->clk_freq == 1000000) && dev->fp_hcnt && dev->fp_lcnt) { + hcnt = dev->fp_hcnt; + lcnt = dev->fp_lcnt; + } else if (dev->fs_hcnt && dev->fs_lcnt) { + hcnt = dev->fs_hcnt; + lcnt = dev->fs_lcnt; + } else { + hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev), + 600, /* tHD;STA = tHIGH = 0.6 us */ + sda_falling_time, + 0, /* 0: DW default, 1: Ideal */ + 0); /* No offset */ + lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev), + 1300, /* tLOW = 1.3 us */ + scl_falling_time, + 0); /* No offset */ + } + dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT); + dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT); + dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); + + if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) == + DW_IC_CON_SPEED_HIGH) { + if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK) + != DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) { + dev_err(dev->dev, "High Speed not supported!\n"); + dev->master_cfg &= ~DW_IC_CON_SPEED_MASK; + dev->master_cfg |= DW_IC_CON_SPEED_FAST; + } else if (dev->hs_hcnt && dev->hs_lcnt) { + hcnt = dev->hs_hcnt; + lcnt = dev->hs_lcnt; + dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT); + dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT); + dev_dbg(dev->dev, "HighSpeed-mode HCNT:LCNT = %d:%d\n", + hcnt, lcnt); + } + } + + /* Configure SDA Hold Time if required */ + reg = dw_readl(dev, DW_IC_COMP_VERSION); + if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { + if (!dev->sda_hold_time) { + /* Keep previous hold time setting if no one set it */ + dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD); + } + /* + * Workaround for avoiding TX arbitration lost in case I2C + * slave pulls SDA down "too quickly" after falling egde of + * SCL by enabling non-zero SDA RX hold. Specification says it + * extends incoming SDA low to high transition while SCL is + * high but it apprears to help also above issue. + */ + if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) + dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; + dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); + } else { + dev_warn(dev->dev, + "Hardware too old to adjust SDA hold time.\n"); + } + + i2c_dw_configure_fifo_master(dev); + i2c_dw_release_lock(dev); + + return 0; +} + +static void i2c_dw_xfer_init(struct dw_i2c_dev *dev) +{ + struct i2c_msg *msgs = dev->msgs; + u32 ic_con, ic_tar = 0; + + /* Disable the adapter */ + __i2c_dw_enable_and_wait(dev, false); + + /* If the slave address is ten bit address, enable 10BITADDR */ + ic_con = dw_readl(dev, DW_IC_CON); + if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) { + ic_con |= DW_IC_CON_10BITADDR_MASTER; + /* + * If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing + * mode has to be enabled via bit 12 of IC_TAR register. + * We set it always as I2C_DYNAMIC_TAR_UPDATE can't be + * detected from registers. + */ + ic_tar = DW_IC_TAR_10BITADDR_MASTER; + } else { + ic_con &= ~DW_IC_CON_10BITADDR_MASTER; + } + + dw_writel(dev, ic_con, DW_IC_CON); + + /* + * Set the slave (target) address and enable 10-bit addressing mode + * if applicable. + */ + dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR); + + /* Enforce disabled interrupts (due to HW issues) */ + i2c_dw_disable_int(dev); + + /* Enable the adapter */ + __i2c_dw_enable(dev, true); + + /* Clear and enable interrupts */ + dw_readl(dev, DW_IC_CLR_INTR); + dw_writel(dev, DW_IC_INTR_MASTER_MASK, DW_IC_INTR_MASK); +} + +/* + * Initiate (and continue) low level master read/write transaction. + * This function is only called from i2c_dw_isr, and pumping i2c_msg + * messages into the tx buffer. Even if the size of i2c_msg data is + * longer than the size of the tx buffer, it handles everything. + */ +static void +i2c_dw_xfer_msg(struct dw_i2c_dev *dev) +{ + struct i2c_msg *msgs = dev->msgs; + u32 intr_mask; + int tx_limit, rx_limit; + u32 addr = msgs[dev->msg_write_idx].addr; + u32 buf_len = dev->tx_buf_len; + u8 *buf = dev->tx_buf; + bool need_restart = false; + + intr_mask = DW_IC_INTR_MASTER_MASK; + + for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) { + u32 flags = msgs[dev->msg_write_idx].flags; + + /* + * 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) { + dev_err(dev->dev, + "%s: invalid target address\n", __func__); + dev->msg_err = -EINVAL; + break; + } + + if (msgs[dev->msg_write_idx].len == 0) { + dev_err(dev->dev, + "%s: invalid message length\n", __func__); + dev->msg_err = -EINVAL; + break; + } + + if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) { + /* new i2c_msg */ + buf = msgs[dev->msg_write_idx].buf; + buf_len = msgs[dev->msg_write_idx].len; + + /* If both IC_EMPTYFIFO_HOLD_MASTER_EN and + * IC_RESTART_EN are set, we must manually + * set restart bit between messages. + */ + if ((dev->master_cfg & DW_IC_CON_RESTART_EN) && + (dev->msg_write_idx > 0)) + need_restart = true; + } + + tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR); + rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR); + + while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) { + u32 cmd = 0; + + /* + * If IC_EMPTYFIFO_HOLD_MASTER_EN is set we must + * manually set the stop bit. However, it cannot be + * detected from the registers so we set it always + * when writing/reading the last byte. + */ + + /* + * i2c-core always sets the buffer length of + * I2C_FUNC_SMBUS_BLOCK_DATA to 1. The length will + * be adjusted when receiving the first byte. + * Thus we can't stop the transaction here. + */ + if (dev->msg_write_idx == dev->msgs_num - 1 && + buf_len == 1 && !(flags & I2C_M_RECV_LEN)) + cmd |= BIT(9); + + if (need_restart) { + cmd |= BIT(10); + need_restart = false; + } + + if (msgs[dev->msg_write_idx].flags & I2C_M_RD) { + + /* Avoid rx buffer overrun */ + if (dev->rx_outstanding >= dev->rx_fifo_depth) + break; + + dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD); + rx_limit--; + dev->rx_outstanding++; + } else + dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD); + tx_limit--; buf_len--; + } + + dev->tx_buf = buf; + dev->tx_buf_len = buf_len; + + /* + * Because we don't know the buffer length in the + * I2C_FUNC_SMBUS_BLOCK_DATA case, we can't stop + * the transaction here. + */ + if (buf_len > 0 || flags & I2C_M_RECV_LEN) { + /* more bytes to be written */ + dev->status |= STATUS_WRITE_IN_PROGRESS; + break; + } else + dev->status &= ~STATUS_WRITE_IN_PROGRESS; + } + + /* + * If i2c_msg index search is completed, we don't need TX_EMPTY + * interrupt any more. + */ + if (dev->msg_write_idx == dev->msgs_num) + intr_mask &= ~DW_IC_INTR_TX_EMPTY; + + if (dev->msg_err) + intr_mask = 0; + + dw_writel(dev, intr_mask, DW_IC_INTR_MASK); +} + +static u8 +i2c_dw_recv_len(struct dw_i2c_dev *dev, u8 len) +{ + struct i2c_msg *msgs = dev->msgs; + u32 flags = msgs[dev->msg_read_idx].flags; + + /* + * Adjust the buffer length and mask the flag + * after receiving the first byte. + */ + len += (flags & I2C_CLIENT_PEC) ? 2 : 1; + dev->tx_buf_len = len - min_t(u8, len, dev->rx_outstanding); + msgs[dev->msg_read_idx].len = len; + msgs[dev->msg_read_idx].flags &= ~I2C_M_RECV_LEN; + + return len; +} + +static void +i2c_dw_read(struct dw_i2c_dev *dev) +{ + struct i2c_msg *msgs = dev->msgs; + int rx_valid; + + 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; + + 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; + } + + rx_valid = dw_readl(dev, DW_IC_RXFLR); + + for (; len > 0 && rx_valid > 0; len--, rx_valid--) { + u32 flags = msgs[dev->msg_read_idx].flags; + + *buf = dw_readl(dev, DW_IC_DATA_CMD); + /* Ensure length byte is a valid value */ + if (flags & I2C_M_RECV_LEN && + *buf <= I2C_SMBUS_BLOCK_MAX && *buf > 0) { + len = i2c_dw_recv_len(dev, *buf); + } + buf++; + dev->rx_outstanding--; + } + + 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); + + pm_runtime_get_sync(dev->dev); + + reinit_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; + dev->abort_source = 0; + dev->rx_outstanding = 0; + + ret = i2c_dw_acquire_lock(dev); + if (ret) + goto done_nolock; + + ret = i2c_dw_wait_bus_not_busy(dev); + if (ret < 0) + goto done; + + /* Start the transfers */ + i2c_dw_xfer_init(dev); + + /* Wait for tx to complete */ + if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) { + dev_err(dev->dev, "controller timed out\n"); + /* i2c_dw_init implicitly disables the adapter */ + i2c_dw_init_master(dev); + ret = -ETIMEDOUT; + goto done; + } + + /* + * We must disable the adapter before returning and signaling the end + * of the current transfer. Otherwise the hardware might continue + * generating interrupts which in turn causes a race condition with + * the following transfer. Needs some more investigation if the + * additional interrupts are a hardware bug or this driver doesn't + * handle them correctly yet. + */ + __i2c_dw_enable(dev, false); + + if (dev->msg_err) { + ret = dev->msg_err; + goto done; + } + + /* No error */ + if (likely(!dev->cmd_err && !dev->status)) { + ret = num; + goto done; + } + + /* We have an error */ + if (dev->cmd_err == DW_IC_ERR_TX_ABRT) { + ret = i2c_dw_handle_tx_abort(dev); + goto done; + } + + if (dev->status) + dev_err(dev->dev, + "transfer terminated early - interrupt latency too high?\n"); + + ret = -EIO; + +done: + i2c_dw_release_lock(dev); + +done_nolock: + pm_runtime_mark_last_busy(dev->dev); + pm_runtime_put_autosuspend(dev->dev); + + return ret; +} + +static const struct i2c_algorithm i2c_dw_algo = { + .master_xfer = i2c_dw_xfer, + .functionality = i2c_dw_func, +}; + +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 = dw_readl(IC_INTR_STAT); + * equals to, + * stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK); + * + * The raw version might be useful for debugging purposes. + */ + stat = dw_readl(dev, 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 + * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR). + * + * Instead, use the separately-prepared IC_CLR_* registers. + */ + if (stat & DW_IC_INTR_RX_UNDER) + dw_readl(dev, DW_IC_CLR_RX_UNDER); + if (stat & DW_IC_INTR_RX_OVER) + dw_readl(dev, DW_IC_CLR_RX_OVER); + if (stat & DW_IC_INTR_TX_OVER) + dw_readl(dev, DW_IC_CLR_TX_OVER); + if (stat & DW_IC_INTR_RD_REQ) + dw_readl(dev, 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 = dw_readl(dev, DW_IC_TX_ABRT_SOURCE); + dw_readl(dev, DW_IC_CLR_TX_ABRT); + } + if (stat & DW_IC_INTR_RX_DONE) + dw_readl(dev, DW_IC_CLR_RX_DONE); + if (stat & DW_IC_INTR_ACTIVITY) + dw_readl(dev, DW_IC_CLR_ACTIVITY); + if (stat & DW_IC_INTR_STOP_DET) + dw_readl(dev, DW_IC_CLR_STOP_DET); + if (stat & DW_IC_INTR_START_DET) + dw_readl(dev, DW_IC_CLR_START_DET); + if (stat & DW_IC_INTR_GEN_CALL) + dw_readl(dev, DW_IC_CLR_GEN_CALL); + + return stat; +} + +/* + * Interrupt service routine. This gets called whenever an I2C master interrupt + * occurs. + */ +static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev) +{ + u32 stat; + + stat = i2c_dw_read_clear_intrbits(dev); + if (stat & DW_IC_INTR_TX_ABRT) { + dev->cmd_err |= DW_IC_ERR_TX_ABRT; + dev->status = STATUS_IDLE; + + /* + * Anytime TX_ABRT is set, the contents of the tx/rx + * buffers are flushed. Make sure to skip them. + */ + dw_writel(dev, 0, DW_IC_INTR_MASK); + goto tx_aborted; + } + + if (stat & DW_IC_INTR_RX_FULL) + i2c_dw_read(dev); + + if (stat & DW_IC_INTR_TX_EMPTY) + 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. + */ + +tx_aborted: + if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err) + complete(&dev->cmd_complete); + else if (unlikely(dev->flags & ACCESS_INTR_MASK)) { + /* Workaround to trigger pending interrupt */ + stat = dw_readl(dev, DW_IC_INTR_MASK); + i2c_dw_disable_int(dev); + dw_writel(dev, stat, DW_IC_INTR_MASK); + } + + return 0; +} + +static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id) +{ + struct dw_i2c_dev *dev = dev_id; + u32 stat, enabled; + + enabled = dw_readl(dev, DW_IC_ENABLE); + stat = dw_readl(dev, DW_IC_RAW_INTR_STAT); + dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat); + if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY)) + return IRQ_NONE; + + i2c_dw_irq_handler_master(dev); + + return IRQ_HANDLED; +} + +int i2c_dw_probe(struct dw_i2c_dev *dev) +{ + struct i2c_adapter *adap = &dev->adapter; + unsigned long irq_flags; + int ret; + + init_completion(&dev->cmd_complete); + + dev->init = i2c_dw_init_master; + dev->disable = i2c_dw_disable; + dev->disable_int = i2c_dw_disable_int; + + ret = dev->init(dev); + if (ret) + return ret; + + snprintf(adap->name, sizeof(adap->name), + "Synopsys DesignWare I2C adapter"); + adap->retries = 3; + adap->algo = &i2c_dw_algo; + adap->dev.parent = dev->dev; + i2c_set_adapdata(adap, dev); + + if (dev->pm_disabled) { + dev_pm_syscore_device(dev->dev, true); + irq_flags = IRQF_NO_SUSPEND; + } else { + irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND; + } + + i2c_dw_disable_int(dev); + ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr, irq_flags, + dev_name(dev->dev), dev); + if (ret) { + dev_err(dev->dev, "failure requesting irq %i: %d\n", + dev->irq, ret); + return ret; + } + + /* + * Increment PM usage count during adapter registration in order to + * avoid possible spurious runtime suspend when adapter device is + * registered to the device core and immediate resume in case bus has + * registered I2C slaves that do I2C transfers in their probe. + */ + pm_runtime_get_noresume(dev->dev); + ret = i2c_add_numbered_adapter(adap); + if (ret) + dev_err(dev->dev, "failure adding adapter: %d\n", ret); + pm_runtime_put_noidle(dev->dev); + + return ret; +} +EXPORT_SYMBOL_GPL(i2c_dw_probe); + +MODULE_DESCRIPTION("Synopsys DesignWare I2C bus master adapter"); +MODULE_LICENSE("GPL"); |