diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-designware-master.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-master.c | 1081 |
1 files changed, 1081 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 0000000000..85dbd0eb53 --- /dev/null +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -0,0 +1,1081 @@ +// 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 <linux/delay.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/pinctrl/consumer.h> +#include <linux/pm_runtime.h> +#include <linux/regmap.h> +#include <linux/reset.h> + +#include "i2c-designware-core.h" + +#define AMD_TIMEOUT_MIN_US 25 +#define AMD_TIMEOUT_MAX_US 250 +#define AMD_MASTERCFG_MASK GENMASK(15, 0) + +static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev) +{ + /* Configure Tx/Rx FIFO threshold levels */ + regmap_write(dev->map, DW_IC_TX_TL, dev->tx_fifo_depth / 2); + regmap_write(dev->map, DW_IC_RX_TL, 0); + + /* Configure the I2C master */ + regmap_write(dev->map, DW_IC_CON, dev->master_cfg); +} + +static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev) +{ + unsigned int comp_param1; + u32 sda_falling_time, scl_falling_time; + struct i2c_timings *t = &dev->timings; + const char *fp_str = ""; + u32 ic_clk; + int ret; + + ret = i2c_dw_acquire_lock(dev); + if (ret) + return ret; + + ret = regmap_read(dev->map, DW_IC_COMP_PARAM_1, &comp_param1); + i2c_dw_release_lock(dev); + if (ret) + return ret; + + /* 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 == I2C_MAX_FAST_MODE_PLUS_FREQ) { + /* + * Check are Fast Mode Plus parameters available. Calculate + * SCL timing parameters for Fast Mode Plus if not set. + */ + if (dev->fp_hcnt && dev->fp_lcnt) { + dev->fs_hcnt = dev->fp_hcnt; + dev->fs_lcnt = dev->fp_lcnt; + } else { + ic_clk = i2c_dw_clk_rate(dev); + dev->fs_hcnt = + i2c_dw_scl_hcnt(ic_clk, + 260, /* tHIGH = 260 ns */ + sda_falling_time, + 0, /* DW default */ + 0); /* No offset */ + dev->fs_lcnt = + i2c_dw_scl_lcnt(ic_clk, + 500, /* tLOW = 500 ns */ + scl_falling_time, + 0); /* No offset */ + } + 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"); + t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ; + 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) { + ic_clk = i2c_dw_clk_rate(dev); + dev->hs_hcnt = + i2c_dw_scl_hcnt(ic_clk, + 160, /* tHIGH = 160 ns */ + sda_falling_time, + 0, /* DW default */ + 0); /* No offset */ + dev->hs_lcnt = + i2c_dw_scl_lcnt(ic_clk, + 320, /* tLOW = 320 ns */ + scl_falling_time, + 0); /* No offset */ + } + 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) + return ret; + + dev_dbg(dev->dev, "Bus speed: %s\n", i2c_freq_mode_string(t->bus_freq_hz)); + return 0; +} + +/** + * i2c_dw_init_master() - 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 */ + regmap_write(dev->map, DW_IC_SS_SCL_HCNT, dev->ss_hcnt); + regmap_write(dev->map, DW_IC_SS_SCL_LCNT, dev->ss_lcnt); + + /* Write fast mode/fast mode plus timing parameters */ + regmap_write(dev->map, DW_IC_FS_SCL_HCNT, dev->fs_hcnt); + regmap_write(dev->map, DW_IC_FS_SCL_LCNT, dev->fs_lcnt); + + /* Write high speed timing parameters if supported */ + if (dev->hs_hcnt && dev->hs_lcnt) { + regmap_write(dev->map, DW_IC_HS_SCL_HCNT, dev->hs_hcnt); + regmap_write(dev->map, DW_IC_HS_SCL_LCNT, dev->hs_lcnt); + } + + /* Write SDA hold time if supported */ + if (dev->sda_hold_time) + regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time); + + 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 = 0, ic_tar = 0; + unsigned int dummy; + + /* Disable the adapter */ + __i2c_dw_disable(dev); + + /* If the slave address is ten bit address, enable 10BITADDR */ + 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; + } + + regmap_update_bits(dev->map, DW_IC_CON, DW_IC_CON_10BITADDR_MASTER, + ic_con); + + /* + * Set the slave (target) address and enable 10-bit addressing mode + * if applicable. + */ + regmap_write(dev->map, DW_IC_TAR, + msgs[dev->msg_write_idx].addr | ic_tar); + + /* Enforce disabled interrupts (due to HW issues) */ + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + + /* Enable the adapter */ + __i2c_dw_enable(dev); + + /* Dummy read to avoid the register getting stuck on Bay Trail */ + regmap_read(dev->map, DW_IC_ENABLE_STATUS, &dummy); + + /* Clear and enable interrupts */ + regmap_read(dev->map, DW_IC_CLR_INTR, &dummy); + regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_MASTER_MASK); +} + +static int i2c_dw_check_stopbit(struct dw_i2c_dev *dev) +{ + u32 val; + int ret; + + ret = regmap_read_poll_timeout(dev->map, DW_IC_INTR_STAT, val, + !(val & DW_IC_INTR_STOP_DET), + 1100, 20000); + if (ret) + dev_err(dev->dev, "i2c timeout error %d\n", ret); + + return ret; +} + +static int i2c_dw_status(struct dw_i2c_dev *dev) +{ + int status; + + status = i2c_dw_wait_bus_not_busy(dev); + if (status) + return status; + + return i2c_dw_check_stopbit(dev); +} + +/* + * Initiate and continue master read/write transaction with polling + * based transfer routine afterward write messages into the Tx buffer. + */ +static int amd_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs, int num_msgs) +{ + struct dw_i2c_dev *dev = i2c_get_adapdata(adap); + int msg_wrt_idx, msg_itr_lmt, buf_len, data_idx; + int cmd = 0, status; + u8 *tx_buf; + unsigned int val; + + /* + * In order to enable the interrupt for UCSI i.e. AMD NAVI GPU card, + * it is mandatory to set the right value in specific register + * (offset:0x474) as per the hardware IP specification. + */ + regmap_write(dev->map, AMD_UCSI_INTR_REG, AMD_UCSI_INTR_EN); + + dev->msgs = msgs; + dev->msgs_num = num_msgs; + i2c_dw_xfer_init(dev); + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + + /* Initiate messages read/write transaction */ + for (msg_wrt_idx = 0; msg_wrt_idx < num_msgs; msg_wrt_idx++) { + tx_buf = msgs[msg_wrt_idx].buf; + buf_len = msgs[msg_wrt_idx].len; + + if (!(msgs[msg_wrt_idx].flags & I2C_M_RD)) + regmap_write(dev->map, DW_IC_TX_TL, buf_len - 1); + /* + * Initiate the i2c read/write transaction of buffer length, + * and poll for bus busy status. For the last message transfer, + * update the command with stopbit enable. + */ + for (msg_itr_lmt = buf_len; msg_itr_lmt > 0; msg_itr_lmt--) { + if (msg_wrt_idx == num_msgs - 1 && msg_itr_lmt == 1) + cmd |= BIT(9); + + if (msgs[msg_wrt_idx].flags & I2C_M_RD) { + /* Due to hardware bug, need to write the same command twice. */ + regmap_write(dev->map, DW_IC_DATA_CMD, 0x100); + regmap_write(dev->map, DW_IC_DATA_CMD, 0x100 | cmd); + if (cmd) { + regmap_write(dev->map, DW_IC_TX_TL, 2 * (buf_len - 1)); + regmap_write(dev->map, DW_IC_RX_TL, 2 * (buf_len - 1)); + /* + * Need to check the stop bit. However, it cannot be + * detected from the registers so we check it always + * when read/write the last byte. + */ + status = i2c_dw_status(dev); + if (status) + return status; + + for (data_idx = 0; data_idx < buf_len; data_idx++) { + regmap_read(dev->map, DW_IC_DATA_CMD, &val); + tx_buf[data_idx] = val; + } + status = i2c_dw_check_stopbit(dev); + if (status) + return status; + } + } else { + regmap_write(dev->map, DW_IC_DATA_CMD, *tx_buf++ | cmd); + usleep_range(AMD_TIMEOUT_MIN_US, AMD_TIMEOUT_MAX_US); + } + } + status = i2c_dw_check_stopbit(dev); + if (status) + return status; + } + + return 0; +} + +static int i2c_dw_poll_tx_empty(struct dw_i2c_dev *dev) +{ + u32 val; + + return regmap_read_poll_timeout(dev->map, DW_IC_RAW_INTR_STAT, val, + val & DW_IC_INTR_TX_EMPTY, + 100, 1000); +} + +static int i2c_dw_poll_rx_full(struct dw_i2c_dev *dev) +{ + u32 val; + + return regmap_read_poll_timeout(dev->map, DW_IC_RAW_INTR_STAT, val, + val & DW_IC_INTR_RX_FULL, + 100, 1000); +} + +static int txgbe_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num_msgs) +{ + struct dw_i2c_dev *dev = i2c_get_adapdata(adap); + int msg_idx, buf_len, data_idx, ret; + unsigned int val, stop = 0; + u8 *buf; + + dev->msgs = msgs; + dev->msgs_num = num_msgs; + i2c_dw_xfer_init(dev); + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + + for (msg_idx = 0; msg_idx < num_msgs; msg_idx++) { + buf = msgs[msg_idx].buf; + buf_len = msgs[msg_idx].len; + + for (data_idx = 0; data_idx < buf_len; data_idx++) { + if (msg_idx == num_msgs - 1 && data_idx == buf_len - 1) + stop |= BIT(9); + + if (msgs[msg_idx].flags & I2C_M_RD) { + regmap_write(dev->map, DW_IC_DATA_CMD, 0x100 | stop); + + ret = i2c_dw_poll_rx_full(dev); + if (ret) + return ret; + + regmap_read(dev->map, DW_IC_DATA_CMD, &val); + buf[data_idx] = val; + } else { + ret = i2c_dw_poll_tx_empty(dev); + if (ret) + return ret; + + regmap_write(dev->map, DW_IC_DATA_CMD, + buf[data_idx] | stop); + } + } + } + + return num_msgs; +} + +/* + * 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; + unsigned int flr; + + 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; + } + + regmap_read(dev->map, DW_IC_TXFLR, &flr); + tx_limit = dev->tx_fifo_depth - flr; + + regmap_read(dev->map, DW_IC_RXFLR, &flr); + rx_limit = dev->rx_fifo_depth - flr; + + 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; + + regmap_write(dev->map, DW_IC_DATA_CMD, + cmd | 0x100); + rx_limit--; + dev->rx_outstanding++; + } else { + regmap_write(dev->map, DW_IC_DATA_CMD, + cmd | *buf++); + } + 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. Also disable the TX_EMPTY IRQ + * while waiting for the data length byte to avoid the + * bogus interrupts flood. + */ + if (flags & I2C_M_RECV_LEN) { + dev->status |= STATUS_WRITE_IN_PROGRESS; + intr_mask &= ~DW_IC_INTR_TX_EMPTY; + break; + } else 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; + + regmap_write(dev->map, DW_IC_INTR_MASK, 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; + + /* + * Received buffer length, re-enable TX_EMPTY interrupt + * to resume the SMBUS transaction. + */ + regmap_update_bits(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_TX_EMPTY, + DW_IC_INTR_TX_EMPTY); + + return len; +} + +static void +i2c_dw_read(struct dw_i2c_dev *dev) +{ + struct i2c_msg *msgs = dev->msgs; + unsigned int rx_valid; + + for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) { + unsigned int tmp; + 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; + } + + regmap_read(dev->map, DW_IC_RXFLR, &rx_valid); + + for (; len > 0 && rx_valid > 0; len--, rx_valid--) { + u32 flags = msgs[dev->msg_read_idx].flags; + + regmap_read(dev->map, DW_IC_DATA_CMD, &tmp); + tmp &= DW_IC_DATA_CMD_DAT; + /* Ensure length byte is a valid value */ + if (flags & I2C_M_RECV_LEN) { + /* + * if IC_EMPTYFIFO_HOLD_MASTER_EN is set, which cannot be + * detected from the registers, the controller can be + * disabled if the STOP bit is set. But it is only set + * after receiving block data response length in + * I2C_FUNC_SMBUS_BLOCK_DATA case. That needs to read + * another byte with STOP bit set when the block data + * response length is invalid to complete the transaction. + */ + if (!tmp || tmp > I2C_SMBUS_BLOCK_MAX) + tmp = 1; + + len = i2c_dw_recv_len(dev, tmp); + } + *buf++ = tmp; + 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); + + /* + * Initiate I2C message transfer when polling mode is enabled, + * As it is polling based transfer mechanism, which does not support + * interrupt based functionalities of existing DesignWare driver. + */ + switch (dev->flags & MODEL_MASK) { + case MODEL_AMD_NAVI_GPU: + ret = amd_i2c_dw_xfer_quirk(adap, msgs, num); + goto done_nolock; + case MODEL_WANGXUN_SP: + ret = txgbe_i2c_dw_xfer_quirk(adap, msgs, num); + goto done_nolock; + default: + break; + } + + 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 = 0; + 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) +{ + unsigned int stat, dummy; + + /* + * The IC_INTR_STAT register just indicates "enabled" interrupts. + * The unmasked raw version of interrupt status bits is 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. + */ + regmap_read(dev->map, DW_IC_INTR_STAT, &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) + regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &dummy); + if (stat & DW_IC_INTR_RX_OVER) + regmap_read(dev->map, DW_IC_CLR_RX_OVER, &dummy); + if (stat & DW_IC_INTR_TX_OVER) + regmap_read(dev->map, DW_IC_CLR_TX_OVER, &dummy); + if (stat & DW_IC_INTR_RD_REQ) + regmap_read(dev->map, DW_IC_CLR_RD_REQ, &dummy); + 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. + */ + regmap_read(dev->map, DW_IC_TX_ABRT_SOURCE, &dev->abort_source); + regmap_read(dev->map, DW_IC_CLR_TX_ABRT, &dummy); + } + if (stat & DW_IC_INTR_RX_DONE) + regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy); + if (stat & DW_IC_INTR_ACTIVITY) + regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy); + if ((stat & DW_IC_INTR_STOP_DET) && + ((dev->rx_outstanding == 0) || (stat & DW_IC_INTR_RX_FULL))) + regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy); + if (stat & DW_IC_INTR_START_DET) + regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy); + if (stat & DW_IC_INTR_GEN_CALL) + regmap_read(dev->map, DW_IC_CLR_GEN_CALL, &dummy); + + return stat; +} + +/* + * Interrupt service routine. This gets called whenever an I2C master interrupt + * occurs. + */ +static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id) +{ + struct dw_i2c_dev *dev = dev_id; + unsigned int stat, enabled; + + regmap_read(dev->map, DW_IC_ENABLE, &enabled); + regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &stat); + if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY)) + return IRQ_NONE; + if (pm_runtime_suspended(dev->dev) || stat == GENMASK(31, 0)) + return IRQ_NONE; + dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat); + + stat = i2c_dw_read_clear_intrbits(dev); + + if (!(dev->status & STATUS_ACTIVE)) { + /* + * Unexpected interrupt in driver point of view. State + * variables are either unset or stale so acknowledge and + * disable interrupts for suppressing further interrupts if + * interrupt really came from this HW (E.g. firmware has left + * the HW active). + */ + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + return IRQ_HANDLED; + } + + if (stat & DW_IC_INTR_TX_ABRT) { + dev->cmd_err |= DW_IC_ERR_TX_ABRT; + dev->status &= ~STATUS_MASK; + dev->rx_outstanding = 0; + + /* + * Anytime TX_ABRT is set, the contents of the tx/rx + * buffers are flushed. Make sure to skip them. + */ + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + 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) && + (dev->rx_outstanding == 0)) + complete(&dev->cmd_complete); + else if (unlikely(dev->flags & ACCESS_INTR_MASK)) { + /* Workaround to trigger pending interrupt */ + regmap_read(dev->map, DW_IC_INTR_MASK, &stat); + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + regmap_write(dev->map, DW_IC_INTR_MASK, stat); + } + + return IRQ_HANDLED; +} + +void i2c_dw_configure_master(struct dw_i2c_dev *dev) +{ + struct i2c_timings *t = &dev->timings; + + dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY; + + dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | + DW_IC_CON_RESTART_EN; + + dev->mode = DW_IC_MASTER; + + switch (t->bus_freq_hz) { + case I2C_MAX_STANDARD_MODE_FREQ: + dev->master_cfg |= DW_IC_CON_SPEED_STD; + break; + case I2C_MAX_HIGH_SPEED_MODE_FREQ: + dev->master_cfg |= DW_IC_CON_SPEED_HIGH; + break; + default: + dev->master_cfg |= DW_IC_CON_SPEED_FAST; + } +} +EXPORT_SYMBOL_GPL(i2c_dw_configure_master); + +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; + + gpio = devm_gpiod_get_optional(dev->dev, "scl", GPIOD_OUT_HIGH); + if (IS_ERR_OR_NULL(gpio)) + return PTR_ERR_OR_ZERO(gpio); + + 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->pinctrl = devm_pinctrl_get(dev->dev); + if (IS_ERR(rinfo->pinctrl)) { + if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER) + return PTR_ERR(rinfo->pinctrl); + + rinfo->pinctrl = NULL; + dev_err(dev->dev, "getting pinctrl info failed: bus recovery might not work\n"); + } else if (!rinfo->pinctrl) { + dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n"); + } + + 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; +} + +static int i2c_dw_poll_adap_quirk(struct dw_i2c_dev *dev) +{ + struct i2c_adapter *adap = &dev->adapter; + int ret; + + pm_runtime_get_noresume(dev->dev); + ret = i2c_add_numbered_adapter(adap); + if (ret) + dev_err(dev->dev, "Failed to add adapter: %d\n", ret); + pm_runtime_put_noidle(dev->dev); + + return ret; +} + +static bool i2c_dw_is_model_poll(struct dw_i2c_dev *dev) +{ + switch (dev->flags & MODEL_MASK) { + case MODEL_AMD_NAVI_GPU: + case MODEL_WANGXUN_SP: + return true; + default: + return false; + } +} + +int i2c_dw_probe_master(struct dw_i2c_dev *dev) +{ + struct i2c_adapter *adap = &dev->adapter; + unsigned long irq_flags; + unsigned int ic_con; + int ret; + + init_completion(&dev->cmd_complete); + + dev->init = i2c_dw_init_master; + dev->disable = i2c_dw_disable; + + ret = i2c_dw_init_regmap(dev); + if (ret) + return ret; + + ret = i2c_dw_set_timings_master(dev); + if (ret) + return ret; + + ret = i2c_dw_set_fifo_size(dev); + if (ret) + return ret; + + /* Lock the bus for accessing DW_IC_CON */ + ret = i2c_dw_acquire_lock(dev); + if (ret) + return ret; + + /* + * On AMD platforms BIOS advertises the bus clear feature + * and enables the SCL/SDA stuck low. SMU FW does the + * bus recovery process. Driver should not ignore this BIOS + * advertisement of bus clear feature. + */ + ret = regmap_read(dev->map, DW_IC_CON, &ic_con); + i2c_dw_release_lock(dev); + if (ret) + return ret; + + if (ic_con & DW_IC_CON_BUS_CLEAR_CTRL) + dev->master_cfg |= DW_IC_CON_BUS_CLEAR_CTRL; + + 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 (i2c_dw_is_model_poll(dev)) + return i2c_dw_poll_adap_quirk(dev); + + if (dev->flags & ACCESS_NO_IRQ_SUSPEND) { + irq_flags = IRQF_NO_SUSPEND; + } else { + irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND; + } + + ret = i2c_dw_acquire_lock(dev); + if (ret) + return ret; + + regmap_write(dev->map, DW_IC_INTR_MASK, 0); + i2c_dw_release_lock(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_master); + +MODULE_DESCRIPTION("Synopsys DesignWare I2C bus master adapter"); +MODULE_LICENSE("GPL"); |