diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-xiic.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-xiic.c | 356 |
1 files changed, 270 insertions, 86 deletions
diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c index 71391b590ada..6bc1575cea6c 100644 --- a/drivers/i2c/busses/i2c-xiic.c +++ b/drivers/i2c/busses/i2c-xiic.c @@ -30,6 +30,8 @@ #include <linux/of.h> #include <linux/clk.h> #include <linux/pm_runtime.h> +#include <linux/iopoll.h> +#include <linux/spinlock.h> #define DRIVER_NAME "xiic-i2c" #define DYNAMIC_MODE_READ_BROKEN_BIT BIT(0) @@ -74,6 +76,9 @@ enum i2c_scl_freq { * @smbus_block_read: Flag to handle block read * @input_clk: Input clock to I2C controller * @i2c_clk: I2C SCL frequency + * @atomic: Mode of transfer + * @atomic_lock: Lock for atomic transfer mode + * @atomic_xfer_state: See STATE_ */ struct xiic_i2c { struct device *dev; @@ -96,6 +101,9 @@ struct xiic_i2c { bool smbus_block_read; unsigned long input_clk; unsigned int i2c_clk; + bool atomic; + spinlock_t atomic_lock; /* Lock for atomic transfer mode */ + enum xilinx_i2c_state atomic_xfer_state; }; struct xiic_version_data { @@ -224,6 +232,8 @@ static const struct timing_regs timing_reg_values[] = { #define XIIC_I2C_TIMEOUT (msecs_to_jiffies(1000)) /* timeout waiting for the controller finish transfers */ #define XIIC_XFER_TIMEOUT (msecs_to_jiffies(10000)) +/* timeout waiting for the controller finish transfers in micro seconds */ +#define XIIC_XFER_TIMEOUT_US 10000000 /* * The following constant is used for the device global interrupt enable @@ -238,6 +248,29 @@ static const struct timing_regs timing_reg_values[] = { static int xiic_start_xfer(struct xiic_i2c *i2c, struct i2c_msg *msgs, int num); static void __xiic_start_xfer(struct xiic_i2c *i2c); +static int xiic_i2c_runtime_suspend(struct device *dev) +{ + struct xiic_i2c *i2c = dev_get_drvdata(dev); + + clk_disable(i2c->clk); + + return 0; +} + +static int xiic_i2c_runtime_resume(struct device *dev) +{ + struct xiic_i2c *i2c = dev_get_drvdata(dev); + int ret; + + ret = clk_enable(i2c->clk); + if (ret) { + dev_err(dev, "Cannot enable clock.\n"); + return ret; + } + + return 0; +} + /* * For the register read and write functions, a little-endian and big-endian * version are necessary. Endianness is detected during the probe function. @@ -374,9 +407,10 @@ static int xiic_setclk(struct xiic_i2c *i2c) unsigned int index = 0; u32 reg_val; - dev_dbg(i2c->adap.dev.parent, - "%s entry, i2c->input_clk: %ld, i2c->i2c_clk: %d\n", - __func__, i2c->input_clk, i2c->i2c_clk); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, + "%s entry, i2c->input_clk: %ld, i2c->i2c_clk: %d\n", + __func__, i2c->input_clk, i2c->i2c_clk); /* If not specified in DT, do not configure in SW. Rely only on Vivado design */ if (!i2c->i2c_clk || !i2c->input_clk) @@ -467,7 +501,8 @@ static int xiic_reinit(struct xiic_i2c *i2c) return ret; /* Enable interrupts */ - xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); + if (!i2c->atomic) + xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); xiic_irq_clr_en(i2c, XIIC_INTR_ARB_LOST_MASK); @@ -549,11 +584,12 @@ static void xiic_read_rx(struct xiic_i2c *i2c) bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1; - dev_dbg(i2c->adap.dev.parent, - "%s entry, bytes in fifo: %d, rem: %d, SR: 0x%x, CR: 0x%x\n", - __func__, bytes_in_fifo, xiic_rx_space(i2c), - xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), - xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, + "%s entry, bytes in fifo: %d, rem: %d, SR: 0x%x, CR: 0x%x\n", + __func__, bytes_in_fifo, xiic_rx_space(i2c), + xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), + xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); if (bytes_in_fifo > xiic_rx_space(i2c)) bytes_in_fifo = xiic_rx_space(i2c); @@ -612,6 +648,26 @@ static void xiic_read_rx(struct xiic_i2c *i2c) } } +static bool xiic_error_check(struct xiic_i2c *i2c) +{ + bool status = false; + u32 pend, isr, ier; + + isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); + ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); + pend = isr & ier; + + if ((pend & XIIC_INTR_ARB_LOST_MASK) || + ((pend & XIIC_INTR_TX_ERROR_MASK) && + !(pend & XIIC_INTR_RX_FULL_MASK))) { + xiic_reinit(i2c); + status = true; + if (i2c->tx_msg || i2c->rx_msg) + i2c->atomic_xfer_state = STATE_ERROR; + } + return status; +} + static int xiic_tx_fifo_space(struct xiic_i2c *i2c) { /* return the actual space left in the FIFO */ @@ -625,8 +681,9 @@ static void xiic_fill_tx_fifo(struct xiic_i2c *i2c) len = (len > fifo_space) ? fifo_space : len; - dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n", - __func__, len, fifo_space); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n", + __func__, len, fifo_space); while (len--) { u16 data = i2c->tx_msg->buf[i2c->tx_pos++]; @@ -649,9 +706,13 @@ static void xiic_fill_tx_fifo(struct xiic_i2c *i2c) xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_MSMS_MASK); } - dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); } xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); + + if (i2c->atomic && xiic_error_check(i2c)) + return; } } @@ -772,14 +833,17 @@ static irqreturn_t xiic_process(int irq, void *dev_id) goto out; } - xiic_fill_tx_fifo(i2c); - - /* current message sent and there is space in the fifo */ - if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) { + if (xiic_tx_space(i2c)) { + xiic_fill_tx_fifo(i2c); + } else { + /* current message fully written */ dev_dbg(i2c->adap.dev.parent, "%s end of message sent, nmsgs: %d\n", __func__, i2c->nmsgs); - if (i2c->nmsgs > 1) { + /* Don't move onto the next message until the TX FIFO empties, + * to ensure that a NAK is not missed. + */ + if (i2c->nmsgs > 1 && (pend & XIIC_INTR_TX_EMPTY_MASK)) { i2c->nmsgs--; i2c->tx_msg++; xfer_more = 1; @@ -790,11 +854,7 @@ static irqreturn_t xiic_process(int irq, void *dev_id) "%s Got TX IRQ but no more to do...\n", __func__); } - } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1)) - /* current frame is sent and is last, - * make sure to disable tx half - */ - xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); + } } if (pend & XIIC_INTR_BNB_MASK) { @@ -844,45 +904,62 @@ static int xiic_bus_busy(struct xiic_i2c *i2c) return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0; } -static int xiic_busy(struct xiic_i2c *i2c) +static int xiic_wait_not_busy(struct xiic_i2c *i2c) { int tries = 3; int err; - if (i2c->tx_msg || i2c->rx_msg) - return -EBUSY; - - /* In single master mode bus can only be busy, when in use by this - * driver. If the register indicates bus being busy for some reason we - * should ignore it, since bus will never be released and i2c will be - * stuck forever. - */ - if (i2c->singlemaster) { - return 0; - } - /* for instance if previous transfer was terminated due to TX error * it might be that the bus is on it's way to become available * give it at most 3 ms to wake */ err = xiic_bus_busy(i2c); while (err && tries--) { - msleep(1); + if (i2c->atomic) + udelay(1000); + else + usleep_range(1000, 1100); err = xiic_bus_busy(i2c); } return err; } +static void xiic_recv_atomic(struct xiic_i2c *i2c) +{ + while (xiic_rx_space(i2c)) { + if (xiic_getreg32(i2c, XIIC_IISR_OFFSET) & XIIC_INTR_RX_FULL_MASK) { + xiic_read_rx(i2c); + + /* Clear Rx full and Tx error interrupts. */ + xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | + XIIC_INTR_TX_ERROR_MASK); + } + if (xiic_error_check(i2c)) + return; + } + + i2c->rx_msg = NULL; + xiic_irq_clr_en(i2c, XIIC_INTR_TX_ERROR_MASK); + + /* send next message if this wasn't the last. */ + if (i2c->nmsgs > 1) { + i2c->nmsgs--; + i2c->tx_msg++; + __xiic_start_xfer(i2c); + } +} + static void xiic_start_recv(struct xiic_i2c *i2c) { u16 rx_watermark; u8 cr = 0, rfd_set = 0; struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg; - dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", - __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), - xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", + __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), + xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); /* Disable Tx interrupts */ xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK | XIIC_INTR_TX_EMPTY_MASK); @@ -980,9 +1057,10 @@ static void xiic_start_recv(struct xiic_i2c *i2c) XIIC_CR_MSMS_MASK) & ~(XIIC_CR_DIR_IS_TX_MASK)); } - dev_dbg(i2c->adap.dev.parent, "%s end, ISR: 0x%x, CR: 0x%x\n", - __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), - xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, "%s end, ISR: 0x%x, CR: 0x%x\n", + __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), + xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); } if (i2c->nmsgs == 1) @@ -992,10 +1070,55 @@ static void xiic_start_recv(struct xiic_i2c *i2c) /* the message is tx:ed */ i2c->tx_pos = msg->len; + i2c->prev_msg_tx = false; + /* Enable interrupts */ - xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); + if (!i2c->atomic) + xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); + else + xiic_recv_atomic(i2c); +} - i2c->prev_msg_tx = false; +static void xiic_send_rem_atomic(struct xiic_i2c *i2c) +{ + while (xiic_tx_space(i2c)) { + if (xiic_tx_fifo_space(i2c)) { + u16 data; + + data = i2c->tx_msg->buf[i2c->tx_pos]; + i2c->tx_pos++; + if (!xiic_tx_space(i2c) && i2c->nmsgs == 1) { + /* last message in transfer -> STOP */ + if (i2c->dynamic) { + data |= XIIC_TX_DYN_STOP_MASK; + } else { + u8 cr; + int status; + + /* Wait till FIFO is empty so STOP is sent last */ + status = xiic_wait_tx_empty(i2c); + if (status) + return; + + /* Write to CR to stop */ + cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); + xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & + ~XIIC_CR_MSMS_MASK); + } + } + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); + } + if (xiic_error_check(i2c)) + return; + } + + if (i2c->nmsgs > 1) { + i2c->nmsgs--; + i2c->tx_msg++; + __xiic_start_xfer(i2c); + } else { + xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); + } } static void xiic_start_send(struct xiic_i2c *i2c) @@ -1004,11 +1127,13 @@ static void xiic_start_send(struct xiic_i2c *i2c) u16 data; struct i2c_msg *msg = i2c->tx_msg; - dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d", - __func__, msg, msg->len); - dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", - __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), - xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); + if (!i2c->atomic) { + dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d", + __func__, msg, msg->len); + dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", + __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), + xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); + } if (i2c->dynamic) { /* write the address */ @@ -1073,19 +1198,27 @@ static void xiic_start_send(struct xiic_i2c *i2c) XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_BNB_MASK); } + i2c->prev_msg_tx = true; + + if (i2c->atomic && !i2c->atomic_xfer_state) + xiic_send_rem_atomic(i2c); } static void __xiic_start_xfer(struct xiic_i2c *i2c) { int fifo_space = xiic_tx_fifo_space(i2c); - dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n", - __func__, i2c->tx_msg, fifo_space); + if (!i2c->atomic) + dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n", + __func__, i2c->tx_msg, fifo_space); if (!i2c->tx_msg) return; + if (i2c->atomic && xiic_error_check(i2c)) + return; + i2c->rx_pos = 0; i2c->tx_pos = 0; i2c->state = STATE_START; @@ -1102,16 +1235,49 @@ static int xiic_start_xfer(struct xiic_i2c *i2c, struct i2c_msg *msgs, int num) bool broken_read, max_read_len, smbus_blk_read; int ret, count; - mutex_lock(&i2c->lock); + if (i2c->atomic) + spin_lock(&i2c->atomic_lock); + else + mutex_lock(&i2c->lock); - ret = xiic_busy(i2c); - if (ret) + if (i2c->tx_msg || i2c->rx_msg) { + dev_err(i2c->adap.dev.parent, + "cannot start a transfer while busy\n"); + ret = -EBUSY; goto out; + } + + i2c->atomic_xfer_state = STATE_DONE; + + /* In single master mode bus can only be busy, when in use by this + * driver. If the register indicates bus being busy for some reason we + * should ignore it, since bus will never be released and i2c will be + * stuck forever. + */ + if (!i2c->singlemaster) { + ret = xiic_wait_not_busy(i2c); + if (ret) { + /* If the bus is stuck in a busy state, such as due to spurious low + * pulses on the bus causing a false start condition to be detected, + * then try to recover by re-initializing the controller and check + * again if the bus is still busy. + */ + dev_warn(i2c->adap.dev.parent, "I2C bus busy timeout, reinitializing\n"); + ret = xiic_reinit(i2c); + if (ret) + goto out; + ret = xiic_wait_not_busy(i2c); + if (ret) + goto out; + } + } i2c->tx_msg = msgs; i2c->rx_msg = NULL; i2c->nmsgs = num; - init_completion(&i2c->completion); + + if (!i2c->atomic) + init_completion(&i2c->completion); /* Decide standard mode or Dynamic mode */ i2c->dynamic = true; @@ -1146,7 +1312,10 @@ static int xiic_start_xfer(struct xiic_i2c *i2c, struct i2c_msg *msgs, int num) __xiic_start_xfer(i2c); out: - mutex_unlock(&i2c->lock); + if (i2c->atomic) + spin_unlock(&i2c->atomic_lock); + else + mutex_unlock(&i2c->lock); return ret; } @@ -1164,10 +1333,8 @@ static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) return err; err = xiic_start_xfer(i2c, msgs, num); - if (err < 0) { - dev_err(adap->dev.parent, "Error xiic_start_xfer\n"); + if (err < 0) goto out; - } err = wait_for_completion_timeout(&i2c->completion, XIIC_XFER_TIMEOUT); mutex_lock(&i2c->lock); @@ -1187,6 +1354,44 @@ out: return err; } +static int xiic_xfer_atomic(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + struct xiic_i2c *i2c = i2c_get_adapdata(adap); + u32 status_reg; + int err; + + err = xiic_i2c_runtime_resume(i2c->dev); + if (err) + return err; + + i2c->atomic = true; + err = xiic_start_xfer(i2c, msgs, num); + if (err < 0) + return err; + + err = readl_poll_timeout_atomic(i2c->base + XIIC_SR_REG_OFFSET, + status_reg, !(status_reg & XIIC_SR_BUS_BUSY_MASK), + 1, XIIC_XFER_TIMEOUT_US); + + if (err) /* Timeout */ + err = -ETIMEDOUT; + + spin_lock(&i2c->atomic_lock); + if (err || i2c->state) { + i2c->tx_msg = NULL; + i2c->rx_msg = NULL; + i2c->nmsgs = 0; + } + + err = (i2c->atomic_xfer_state == STATE_DONE) ? num : -EIO; + spin_unlock(&i2c->atomic_lock); + + i2c->atomic = false; + xiic_i2c_runtime_suspend(i2c->dev); + + return err; +} + static u32 xiic_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA; @@ -1194,6 +1399,7 @@ static u32 xiic_func(struct i2c_adapter *adap) static const struct i2c_algorithm xiic_algorithm = { .master_xfer = xiic_xfer, + .master_xfer_atomic = xiic_xfer_atomic, .functionality = xiic_func, }; @@ -1257,6 +1463,7 @@ static int xiic_i2c_probe(struct platform_device *pdev) DRIVER_NAME " %s", pdev->name); mutex_init(&i2c->lock); + spin_lock_init(&i2c->atomic_lock); i2c->clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(i2c->clk)) @@ -1282,7 +1489,7 @@ static int xiic_i2c_probe(struct platform_device *pdev) pdev->name, i2c); if (ret < 0) { - dev_err(&pdev->dev, "Cannot claim IRQ\n"); + dev_err_probe(&pdev->dev, ret, "Cannot claim IRQ\n"); goto err_pm_disable; } @@ -1303,7 +1510,7 @@ static int xiic_i2c_probe(struct platform_device *pdev) ret = xiic_reinit(i2c); if (ret < 0) { - dev_err(&pdev->dev, "Cannot xiic_reinit\n"); + dev_err_probe(&pdev->dev, ret, "Cannot xiic_reinit\n"); goto err_pm_disable; } @@ -1326,8 +1533,8 @@ static int xiic_i2c_probe(struct platform_device *pdev) return 0; err_pm_disable: - pm_runtime_set_suspended(&pdev->dev); pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); return ret; } @@ -1354,29 +1561,6 @@ static void xiic_i2c_remove(struct platform_device *pdev) pm_runtime_dont_use_autosuspend(&pdev->dev); } -static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev) -{ - struct xiic_i2c *i2c = dev_get_drvdata(dev); - - clk_disable(i2c->clk); - - return 0; -} - -static int __maybe_unused xiic_i2c_runtime_resume(struct device *dev) -{ - struct xiic_i2c *i2c = dev_get_drvdata(dev); - int ret; - - ret = clk_enable(i2c->clk); - if (ret) { - dev_err(dev, "Cannot enable clock.\n"); - return ret; - } - - return 0; -} - static const struct dev_pm_ops xiic_dev_pm_ops = { SET_RUNTIME_PM_OPS(xiic_i2c_runtime_suspend, xiic_i2c_runtime_resume, NULL) @@ -1384,7 +1568,7 @@ static const struct dev_pm_ops xiic_dev_pm_ops = { static struct platform_driver xiic_i2c_driver = { .probe = xiic_i2c_probe, - .remove_new = xiic_i2c_remove, + .remove = xiic_i2c_remove, .driver = { .name = DRIVER_NAME, .of_match_table = of_match_ptr(xiic_of_match), |