/* * 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. * ---------------------------------------------------------------------------- * */ /* * Includes Intel Corporation's changes/modifications dated: 2018. * Changed/modified portions - Copyright (c) 2018, Intel Corporation. */ #include #include #include #include #include #include #include #include #include #include "i2c-designware-core.h" /* * 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_HS_SCL_HCNT 0x24 #define DW_IC_HS_SCL_LCNT 0x28 #define DW_IC_INTR_STAT 0x2c #define DW_IC_INTR_MASK 0x30 #define DW_IC_RAW_INTR_STAT 0x34 #define DW_IC_RX_TL 0x38 #define DW_IC_TX_TL 0x3c #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_SDA_HOLD 0x7c #define DW_IC_TX_ABRT_SOURCE 0x80 #define DW_IC_ENABLE_STATUS 0x9c #define DW_IC_COMP_PARAM_1 0xf4 #define DW_IC_COMP_VERSION 0xf8 #define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A #define DW_IC_COMP_TYPE 0xfc #define DW_IC_COMP_TYPE_VALUE 0x44570140 #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_RESETS 0x804 # define DW_IC_RESETS_FUNC BIT(0) # define DW_IC_RESETS_APB BIT(1) #define DW_IC_GENERAL 0x808 #define DW_IC_INTR_DEFAULT_MASK (DW_IC_INTR_RX_FULL | \ DW_IC_INTR_TX_EMPTY | \ DW_IC_INTR_TX_ABRT | \ DW_IC_INTR_STOP_DET) #define DW_IC_STATUS_ACTIVITY 0x1 #define DW_IC_SDA_HOLD_RX_SHIFT 16 #define DW_IC_SDA_HOLD_RX_MASK GENMASK(23, DW_IC_SDA_HOLD_RX_SHIFT) #define DW_IC_ERR_TX_ABRT 0x1 #define DW_IC_TAR_10BITADDR_MASTER BIT(12) #define DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH (BIT(2) | BIT(3)) #define DW_IC_COMP_PARAM_1_SPEED_MODE_MASK GENMASK(3, 2) /* * 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 ABRT_MASTER_DIS 11 #define ARB_LOST 12 #define DW_IC_TX_ABRT_7B_ADDR_NOACK (1UL << ABRT_7B_ADDR_NOACK) #define DW_IC_TX_ABRT_10ADDR1_NOACK (1UL << ABRT_10ADDR1_NOACK) #define DW_IC_TX_ABRT_10ADDR2_NOACK (1UL << ABRT_10ADDR2_NOACK) #define DW_IC_TX_ABRT_TXDATA_NOACK (1UL << ABRT_TXDATA_NOACK) #define DW_IC_TX_ABRT_GCALL_NOACK (1UL << ABRT_GCALL_NOACK) #define DW_IC_TX_ABRT_GCALL_READ (1UL << ABRT_GCALL_READ) #define DW_IC_TX_ABRT_SBYTE_ACKDET (1UL << ABRT_SBYTE_ACKDET) #define DW_IC_TX_ABRT_SBYTE_NORSTRT (1UL << ABRT_SBYTE_NORSTRT) #define DW_IC_TX_ABRT_10B_RD_NORSTRT (1UL << ABRT_10B_RD_NORSTRT) #define DW_IC_TX_ABRT_MASTER_DIS (1UL << ABRT_MASTER_DIS) #define DW_IC_TX_ARB_LOST (1UL << ARB_LOST) #define DW_IC_TX_ABRT_NOACK (DW_IC_TX_ABRT_7B_ADDR_NOACK | \ DW_IC_TX_ABRT_10ADDR1_NOACK | \ DW_IC_TX_ABRT_10ADDR2_NOACK | \ DW_IC_TX_ABRT_TXDATA_NOACK | \ DW_IC_TX_ABRT_GCALL_NOACK) 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)", [ABRT_MASTER_DIS] = "trying to use disabled adapter", [ARB_LOST] = "lost arbitration", }; static u32 dw_readl(struct dw_i2c_dev *dev, int offset) { u32 value; if (dev->accessor_flags & ACCESS_16BIT) value = readw_relaxed(dev->base + offset) | (readw_relaxed(dev->base + offset + 2) << 16); else value = readl_relaxed(dev->base + offset); if (dev->accessor_flags & ACCESS_SWAP) return swab32(value); else return value; } static void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset) { if (dev->accessor_flags & ACCESS_SWAP) b = swab32(b); if (dev->accessor_flags & ACCESS_16BIT) { writew_relaxed((u16)b, dev->base + offset); writew_relaxed((u16)(b >> 16), dev->base + offset + 2); } else { writel_relaxed(b, dev->base + offset); } } 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 + 500000) / 1000000 - 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) + 500000) / 1000000 - 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) + 500000) / 1000000) - 1 + offset; } static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable) { dw_writel(dev, enable, DW_IC_ENABLE); } static void __i2c_dw_enable_and_wait(struct dw_i2c_dev *dev, bool enable) { int timeout = 100; do { __i2c_dw_enable(dev, enable); if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable) return; /* * Wait 10 times the signaling period of the highest I2C * transfer supported by the driver (for 400KHz this is * 25us) as described in the DesignWare I2C databook. */ if (dev->polling) udelay(25); else usleep_range(25, 250); } while (timeout--); dev_warn(dev->dev, "timeout in %sabling adapter\n", enable ? "en" : "dis"); } static unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev) { /* * Clock is not necessary if we got LCNT/HCNT values directly from * the platform code. */ if (WARN_ON_ONCE(!dev->get_clk_rate_khz)) return 0; return dev->get_clk_rate_khz(dev); } #if 0 static int i2c_dw_acquire_lock(struct dw_i2c_dev *dev) { int ret; if (!dev->acquire_lock) return 0; ret = dev->acquire_lock(dev); if (!ret) return 0; dev_err(dev->dev, "couldn't acquire bus ownership\n"); return ret; } #endif static void i2c_dw_release_lock(struct dw_i2c_dev *dev) { if (dev->release_lock) dev->release_lock(dev); } /** * 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. * This function must be wrapped by acquire_ownership for shared host. */ int i2c_dw_init(struct dw_i2c_dev *dev) { u32 hcnt, lcnt; u32 reg, comp_param1; u32 sda_falling_time, scl_falling_time; int ret; int timeout = TIMEOUT; /* * acquire_ownership may disable local irq. * So release it first and do operations that might sleep. */ if (dev->shared_host && dev->release_ownership) dev->release_ownership(); if (dev->shared_host && dev->acquire_ownership) { ret = dev->acquire_ownership(); if (ret < 0) { dev_WARN(dev->dev, "%s couldn't acquire ownership\n", __func__); return ret; } } do { /* * We need to reset the controller if it's not accessible */ if (dw_readl(dev, DW_IC_COMP_TYPE) == DW_IC_COMP_TYPE_VALUE) break; /* * reset apb and clock domain */ dw_writel(dev, 0, DW_IC_RESETS); dw_writel(dev, 0, DW_IC_GENERAL); if (dev->polling) udelay(10); else usleep_range(10, 100); dw_writel(dev, DW_IC_RESETS_APB | DW_IC_RESETS_FUNC, DW_IC_RESETS); if (dev->polling) udelay(10); else usleep_range(10, 100); } while (timeout--); if (unlikely(timeout == 0)) dev_err(dev->dev, "controller time out\n"); reg = dw_readl(dev, DW_IC_COMP_TYPE); if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) { /* Configure register endianess access */ dev->accessor_flags |= ACCESS_SWAP; } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { /* Configure register access mode 16bit */ dev->accessor_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"); } /* 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_release_lock(dev); return 0; } EXPORT_SYMBOL_GPL(i2c_dw_init); /* * Waiting for bus not busy */ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) { int timeout = TIMEOUT; while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) { if (timeout <= 0) { dev_warn(dev->dev, "timeout waiting for bus ready\n"); return -ETIMEDOUT; } timeout--; if (dev->polling) { /* Wait less if it's a polling */ udelay(25); } else usleep_range(1000, 1100); } 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); /* 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); if (!dev->polling) dw_writel(dev, DW_IC_INTR_DEFAULT_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_DEFAULT_MASK; 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) { 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. */ if (dev->msg_write_idx == dev->msgs_num - 1 && buf_len == 1) 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; if (buf_len > 0) { /* 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; if (!dev->polling) dw_writel(dev, intr_mask, DW_IC_INTR_MASK); } 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--) { *buf++ = dw_readl(dev, DW_IC_DATA_CMD); 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; } } static int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) { unsigned long abort_source = dev->abort_source; int i; if (abort_source & DW_IC_TX_ABRT_NOACK) { for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) dev_dbg(dev->dev, "%s: %s\n", __func__, abort_sources[i]); return -EREMOTEIO; } for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); if (abort_source & DW_IC_TX_ARB_LOST) return -EAGAIN; else if (abort_source & DW_IC_TX_ABRT_GCALL_READ) return -EINVAL; /* wrong msgs[] data */ else return -EIO; } /* * Return value resembles wait_for_completion_timeout. */ static int i2c_dw_xfer_polling(struct dw_i2c_dev *dev) { int ret = 1, timeout = 100000 /* 1 second timeout */; u32 stat = 0; while (--timeout) { stat = dw_readl(dev, DW_IC_RAW_INTR_STAT); /* If error occurs, set cmd_err and go out. */ if (stat & DW_IC_INTR_TX_ABRT) { dev->cmd_err |= DW_IC_ERR_TX_ABRT; dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE); dev->status = STATUS_IDLE; goto out; } i2c_dw_read(dev); i2c_dw_xfer_msg(dev); if (stat & DW_IC_INTR_STOP_DET) goto out; udelay(10); } if (timeout == 0) ret = 0; out: return ret; } /* * 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); if (dev->shared_host) usleep_range(10000, 12000); 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; /* if the host is shared between other units on the SoC */ if (dev->shared_host && dev->acquire_ownership) { ret = dev->acquire_ownership(); if (ret < 0) { dev_WARN(dev->dev, "couldnt acquire ownership\n"); goto done_nolock; } } ret = i2c_dw_wait_bus_not_busy(dev); if (ret < 0) goto done; /* start the transfers */ i2c_dw_xfer_init(dev); if (dev->polling) ret = i2c_dw_xfer_polling(dev); else if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) { /* wait for tx to complete */ dev_err(dev->dev, "controller timed out\n"); /* i2c_dw_init implicitly disables the adapter */ i2c_dw_init(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: if (dev->shared_host && dev->release_ownership) dev->release_ownership(); done_nolock: pm_runtime_mark_last_busy(dev->dev); pm_runtime_put_autosuspend(dev->dev); return ret; } static u32 i2c_dw_func(struct i2c_adapter *adap) { struct dw_i2c_dev *dev = i2c_get_adapdata(adap); return dev->functionality; } static 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 interrupt * occurs. */ 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, "%s: enabled=%#x stat=%#x\n", __func__, enabled, stat); if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY)) return IRQ_NONE; 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) { /* * Check DW_IC_RXFLR register and * read from the RX FIFO if it's not * empty. */ if ((stat & DW_IC_INTR_STOP_DET) && dw_readl(dev, DW_IC_RXFLR) > 0) i2c_dw_read(dev); complete(&dev->cmd_complete); } else if (unlikely(dev->accessor_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 IRQ_HANDLED; } void i2c_dw_disable(struct dw_i2c_dev *dev) { /* Disable controller */ __i2c_dw_enable_and_wait(dev, false); /* Disable all interupts */ dw_writel(dev, 0, DW_IC_INTR_MASK); dw_readl(dev, DW_IC_CLR_INTR); } EXPORT_SYMBOL_GPL(i2c_dw_disable); void i2c_dw_disable_int(struct dw_i2c_dev *dev) { dw_writel(dev, 0, DW_IC_INTR_MASK); } EXPORT_SYMBOL_GPL(i2c_dw_disable_int); u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev) { return dw_readl(dev, DW_IC_COMP_PARAM_1); } EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param); int i2c_dw_probe(struct dw_i2c_dev *dev) { struct i2c_adapter *adap = &dev->adapter; int r; init_completion(&dev->cmd_complete); r = i2c_dw_init(dev); if (r) return r; snprintf(adap->name, sizeof(adap->name), "Synopsys DesignWare I2C adapter"); adap->retries = 3; adap->timeout = 3 * HZ; adap->algo = &i2c_dw_algo; adap->dev.parent = dev->dev; i2c_set_adapdata(adap, dev); i2c_dw_disable_int(dev); r = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr, IRQF_SHARED | IRQF_COND_SUSPEND, dev_name(dev->dev), dev); if (r) { dev_err(dev->dev, "failure requesting irq %i: %d\n", dev->irq, r); return r; } /* * 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); r = i2c_add_numbered_adapter(adap); if (r) dev_err(dev->dev, "failure adding adapter: %d\n", r); pm_runtime_put_noidle(dev->dev); return r; } EXPORT_SYMBOL_GPL(i2c_dw_probe); MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); MODULE_LICENSE("GPL");