// SPDX-License-Identifier: GPL-2.0-or-later /* * 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. */ #include #include #include #include #include #include #include #include #include #include #include #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); } static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev) { const char *mode_str, *fp_str = ""; u32 comp_param1; u32 sda_falling_time, scl_falling_time; struct i2c_timings *t = &dev->timings; u32 ic_clk; int ret; ret = i2c_dw_acquire_lock(dev); if (ret) return ret; comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1); i2c_dw_release_lock(dev); /* Set standard and fast speed dividers for high/low periods */ sda_falling_time = t->sda_fall_ns ?: 300; /* ns */ scl_falling_time = t->scl_fall_ns ?: 300; /* ns */ /* Calculate SCL timing parameters for standard mode if not set */ if (!dev->ss_hcnt || !dev->ss_lcnt) { ic_clk = i2c_dw_clk_rate(dev); dev->ss_hcnt = i2c_dw_scl_hcnt(ic_clk, 4000, /* tHD;STA = tHIGH = 4.0 us */ sda_falling_time, 0, /* 0: DW default, 1: Ideal */ 0); /* No offset */ dev->ss_lcnt = i2c_dw_scl_lcnt(ic_clk, 4700, /* tLOW = 4.7 us */ scl_falling_time, 0); /* No offset */ } dev_dbg(dev->dev, "Standard Mode HCNT:LCNT = %d:%d\n", dev->ss_hcnt, dev->ss_lcnt); /* * Set SCL timing parameters for fast mode or fast mode plus. Only * difference is the timing parameter values since the registers are * the same. */ if (t->bus_freq_hz == 1000000) { /* * Check are fast mode plus parameters available and use * fast mode if not. */ if (dev->fp_hcnt && dev->fp_lcnt) { dev->fs_hcnt = dev->fp_hcnt; dev->fs_lcnt = dev->fp_lcnt; fp_str = " Plus"; } } /* * Calculate SCL timing parameters for fast mode if not set. They are * needed also in high speed mode. */ if (!dev->fs_hcnt || !dev->fs_lcnt) { ic_clk = i2c_dw_clk_rate(dev); dev->fs_hcnt = i2c_dw_scl_hcnt(ic_clk, 600, /* tHD;STA = tHIGH = 0.6 us */ sda_falling_time, 0, /* 0: DW default, 1: Ideal */ 0); /* No offset */ dev->fs_lcnt = i2c_dw_scl_lcnt(ic_clk, 1300, /* tLOW = 1.3 us */ scl_falling_time, 0); /* No offset */ } dev_dbg(dev->dev, "Fast Mode%s HCNT:LCNT = %d:%d\n", fp_str, dev->fs_hcnt, dev->fs_lcnt); /* Check is high speed possible and fall back to fast mode if not */ 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; dev->hs_hcnt = 0; dev->hs_lcnt = 0; } else if (dev->hs_hcnt && dev->hs_lcnt) { dev_dbg(dev->dev, "High Speed Mode HCNT:LCNT = %d:%d\n", dev->hs_hcnt, dev->hs_lcnt); } } ret = i2c_dw_set_sda_hold(dev); if (ret) goto out; switch (dev->master_cfg & DW_IC_CON_SPEED_MASK) { case DW_IC_CON_SPEED_STD: mode_str = "Standard Mode"; break; case DW_IC_CON_SPEED_HIGH: mode_str = "High Speed Mode"; break; default: mode_str = "Fast Mode"; } dev_dbg(dev->dev, "Bus speed: %s%s\n", mode_str, fp_str); out: return ret; } /** * 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) { int ret; ret = i2c_dw_acquire_lock(dev); if (ret) return ret; /* Disable the adapter */ __i2c_dw_disable(dev); /* Write standard speed timing parameters */ dw_writel(dev, dev->ss_hcnt, DW_IC_SS_SCL_HCNT); dw_writel(dev, dev->ss_lcnt, DW_IC_SS_SCL_LCNT); /* Write fast mode/fast mode plus timing parameters */ dw_writel(dev, dev->fs_hcnt, DW_IC_FS_SCL_HCNT); dw_writel(dev, dev->fs_lcnt, DW_IC_FS_SCL_LCNT); /* Write high speed timing parameters if supported */ if (dev->hs_hcnt && dev->hs_lcnt) { dw_writel(dev, dev->hs_hcnt, DW_IC_HS_SCL_HCNT); dw_writel(dev, dev->hs_lcnt, DW_IC_HS_SCL_LCNT); } /* Write SDA hold time if supported */ if (dev->sda_hold_time) dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); 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_disable(dev); /* 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); /* Dummy read to avoid the register getting stuck on Bay Trail */ dw_readl(dev, DW_IC_ENABLE_STATUS); /* 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 (!(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); if (dev_WARN_ONCE(dev->dev, dev->suspended, "Transfer while suspended\n")) { ret = -ESHUTDOWN; goto done_nolock; } 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_recover_bus(&dev->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_disable_nowait(dev); 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 const struct i2c_adapter_quirks i2c_dw_quirks = { .flags = I2C_AQ_NO_ZERO_LEN, }; 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; } static void i2c_dw_prepare_recovery(struct i2c_adapter *adap) { struct dw_i2c_dev *dev = i2c_get_adapdata(adap); i2c_dw_disable(dev); reset_control_assert(dev->rst); i2c_dw_prepare_clk(dev, false); } static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap) { struct dw_i2c_dev *dev = i2c_get_adapdata(adap); i2c_dw_prepare_clk(dev, true); reset_control_deassert(dev->rst); i2c_dw_init_master(dev); } static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev) { struct i2c_bus_recovery_info *rinfo = &dev->rinfo; struct i2c_adapter *adap = &dev->adapter; struct gpio_desc *gpio; int r; gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH); if (IS_ERR(gpio)) { r = PTR_ERR(gpio); if (r == -ENOENT || r == -ENOSYS) return 0; return r; } rinfo->scl_gpiod = gpio; gpio = devm_gpiod_get_optional(dev->dev, "sda", GPIOD_IN); if (IS_ERR(gpio)) return PTR_ERR(gpio); rinfo->sda_gpiod = gpio; rinfo->recover_bus = i2c_generic_scl_recovery; rinfo->prepare_recovery = i2c_dw_prepare_recovery; rinfo->unprepare_recovery = i2c_dw_unprepare_recovery; adap->bus_recovery_info = rinfo; dev_info(dev->dev, "running with gpio recovery mode! scl%s", rinfo->sda_gpiod ? ",sda" : ""); return 0; } 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 = i2c_dw_set_reg_access(dev); if (ret) return ret; ret = i2c_dw_set_timings_master(dev); if (ret) return ret; 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->quirks = &i2c_dw_quirks; adap->dev.parent = dev->dev; i2c_set_adapdata(adap, dev); if (dev->flags & ACCESS_NO_IRQ_SUSPEND) { 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; } ret = i2c_dw_init_recovery_info(dev); if (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");