// SPDX-License-Identifier: GPL-2.0-only /* * i2c-xiic.c * Copyright (c) 2002-2007 Xilinx Inc. * Copyright (c) 2009-2010 Intel Corporation * * This code was implemented by Mocean Laboratories AB when porting linux * to the automotive development board Russellville. The copyright holder * as seen in the header is Intel corporation. * Mocean Laboratories forked off the GNU/Linux platform work into a * separate company called Pelagicore AB, which committed the code to the * kernel. */ /* Supports: * Xilinx IIC */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "xiic-i2c" enum xilinx_i2c_state { STATE_DONE, STATE_ERROR, STATE_START }; enum xiic_endian { LITTLE, BIG }; /** * struct xiic_i2c - Internal representation of the XIIC I2C bus * @dev: Pointer to device structure * @base: Memory base of the HW registers * @wait: Wait queue for callers * @adap: Kernel adapter representation * @tx_msg: Messages from above to be sent * @lock: Mutual exclusion * @tx_pos: Current pos in TX message * @nmsgs: Number of messages in tx_msg * @rx_msg: Current RX message * @rx_pos: Position within current RX message * @endianness: big/little-endian byte order * @clk: Pointer to AXI4-lite input clock * @state: See STATE_ * @singlemaster: Indicates bus is single master */ struct xiic_i2c { struct device *dev; void __iomem *base; wait_queue_head_t wait; struct i2c_adapter adap; struct i2c_msg *tx_msg; struct mutex lock; unsigned int tx_pos; unsigned int nmsgs; struct i2c_msg *rx_msg; int rx_pos; enum xiic_endian endianness; struct clk *clk; enum xilinx_i2c_state state; bool singlemaster; }; #define XIIC_MSB_OFFSET 0 #define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET) /* * Register offsets in bytes from RegisterBase. Three is added to the * base offset to access LSB (IBM style) of the word */ #define XIIC_CR_REG_OFFSET (0x00+XIIC_REG_OFFSET) /* Control Register */ #define XIIC_SR_REG_OFFSET (0x04+XIIC_REG_OFFSET) /* Status Register */ #define XIIC_DTR_REG_OFFSET (0x08+XIIC_REG_OFFSET) /* Data Tx Register */ #define XIIC_DRR_REG_OFFSET (0x0C+XIIC_REG_OFFSET) /* Data Rx Register */ #define XIIC_ADR_REG_OFFSET (0x10+XIIC_REG_OFFSET) /* Address Register */ #define XIIC_TFO_REG_OFFSET (0x14+XIIC_REG_OFFSET) /* Tx FIFO Occupancy */ #define XIIC_RFO_REG_OFFSET (0x18+XIIC_REG_OFFSET) /* Rx FIFO Occupancy */ #define XIIC_TBA_REG_OFFSET (0x1C+XIIC_REG_OFFSET) /* 10 Bit Address reg */ #define XIIC_RFD_REG_OFFSET (0x20+XIIC_REG_OFFSET) /* Rx FIFO Depth reg */ #define XIIC_GPO_REG_OFFSET (0x24+XIIC_REG_OFFSET) /* Output Register */ /* Control Register masks */ #define XIIC_CR_ENABLE_DEVICE_MASK 0x01 /* Device enable = 1 */ #define XIIC_CR_TX_FIFO_RESET_MASK 0x02 /* Transmit FIFO reset=1 */ #define XIIC_CR_MSMS_MASK 0x04 /* Master starts Txing=1 */ #define XIIC_CR_DIR_IS_TX_MASK 0x08 /* Dir of tx. Txing=1 */ #define XIIC_CR_NO_ACK_MASK 0x10 /* Tx Ack. NO ack = 1 */ #define XIIC_CR_REPEATED_START_MASK 0x20 /* Repeated start = 1 */ #define XIIC_CR_GENERAL_CALL_MASK 0x40 /* Gen Call enabled = 1 */ /* Status Register masks */ #define XIIC_SR_GEN_CALL_MASK 0x01 /* 1=a mstr issued a GC */ #define XIIC_SR_ADDR_AS_SLAVE_MASK 0x02 /* 1=when addr as slave */ #define XIIC_SR_BUS_BUSY_MASK 0x04 /* 1 = bus is busy */ #define XIIC_SR_MSTR_RDING_SLAVE_MASK 0x08 /* 1=Dir: mstr <-- slave */ #define XIIC_SR_TX_FIFO_FULL_MASK 0x10 /* 1 = Tx FIFO full */ #define XIIC_SR_RX_FIFO_FULL_MASK 0x20 /* 1 = Rx FIFO full */ #define XIIC_SR_RX_FIFO_EMPTY_MASK 0x40 /* 1 = Rx FIFO empty */ #define XIIC_SR_TX_FIFO_EMPTY_MASK 0x80 /* 1 = Tx FIFO empty */ /* Interrupt Status Register masks Interrupt occurs when... */ #define XIIC_INTR_ARB_LOST_MASK 0x01 /* 1 = arbitration lost */ #define XIIC_INTR_TX_ERROR_MASK 0x02 /* 1=Tx error/msg complete */ #define XIIC_INTR_TX_EMPTY_MASK 0x04 /* 1 = Tx FIFO/reg empty */ #define XIIC_INTR_RX_FULL_MASK 0x08 /* 1=Rx FIFO/reg=OCY level */ #define XIIC_INTR_BNB_MASK 0x10 /* 1 = Bus not busy */ #define XIIC_INTR_AAS_MASK 0x20 /* 1 = when addr as slave */ #define XIIC_INTR_NAAS_MASK 0x40 /* 1 = not addr as slave */ #define XIIC_INTR_TX_HALF_MASK 0x80 /* 1 = TX FIFO half empty */ /* The following constants specify the depth of the FIFOs */ #define IIC_RX_FIFO_DEPTH 16 /* Rx fifo capacity */ #define IIC_TX_FIFO_DEPTH 16 /* Tx fifo capacity */ /* The following constants specify groups of interrupts that are typically * enabled or disables at the same time */ #define XIIC_TX_INTERRUPTS \ (XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK) #define XIIC_TX_RX_INTERRUPTS (XIIC_INTR_RX_FULL_MASK | XIIC_TX_INTERRUPTS) /* * Tx Fifo upper bit masks. */ #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */ #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */ /* * The following constants define the register offsets for the Interrupt * registers. There are some holes in the memory map for reserved addresses * to allow other registers to be added and still match the memory map of the * interrupt controller registers */ #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */ #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */ #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */ #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */ #define XIIC_RESET_MASK 0xAUL #define XIIC_PM_TIMEOUT 1000 /* ms */ /* timeout waiting for the controller to respond */ #define XIIC_I2C_TIMEOUT (msecs_to_jiffies(1000)) /* * The following constant is used for the device global interrupt enable * register, to enable all interrupts for the device, this is the only bit * in the register */ #define XIIC_GINTR_ENABLE_MASK 0x80000000UL #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos) #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos) static int xiic_start_xfer(struct xiic_i2c *i2c); static void __xiic_start_xfer(struct xiic_i2c *i2c); /* * For the register read and write functions, a little-endian and big-endian * version are necessary. Endianness is detected during the probe function. * Only the least significant byte [doublet] of the register are ever * accessed. This requires an offset of 3 [2] from the base address for * big-endian systems. */ static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value) { if (i2c->endianness == LITTLE) iowrite8(value, i2c->base + reg); else iowrite8(value, i2c->base + reg + 3); } static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg) { u8 ret; if (i2c->endianness == LITTLE) ret = ioread8(i2c->base + reg); else ret = ioread8(i2c->base + reg + 3); return ret; } static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value) { if (i2c->endianness == LITTLE) iowrite16(value, i2c->base + reg); else iowrite16be(value, i2c->base + reg + 2); } static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value) { if (i2c->endianness == LITTLE) iowrite32(value, i2c->base + reg); else iowrite32be(value, i2c->base + reg); } static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg) { u32 ret; if (i2c->endianness == LITTLE) ret = ioread32(i2c->base + reg); else ret = ioread32be(i2c->base + reg); return ret; } static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask) { u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask); } static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask) { u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask); } static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask) { u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask); } static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask) { xiic_irq_clr(i2c, mask); xiic_irq_en(i2c, mask); } static int xiic_clear_rx_fifo(struct xiic_i2c *i2c) { u8 sr; unsigned long timeout; timeout = jiffies + XIIC_I2C_TIMEOUT; for (sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET); !(sr & XIIC_SR_RX_FIFO_EMPTY_MASK); sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)) { xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); if (time_after(jiffies, timeout)) { dev_err(i2c->dev, "Failed to clear rx fifo\n"); return -ETIMEDOUT; } } return 0; } static int xiic_reinit(struct xiic_i2c *i2c) { int ret; xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); /* Set receive Fifo depth to maximum (zero based). */ xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1); /* Reset Tx Fifo. */ xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); /* Enable IIC Device, remove Tx Fifo reset & disable general call. */ xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK); /* make sure RX fifo is empty */ ret = xiic_clear_rx_fifo(i2c); if (ret) return ret; /* Enable interrupts */ xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); xiic_irq_clr_en(i2c, XIIC_INTR_ARB_LOST_MASK); return 0; } static void xiic_deinit(struct xiic_i2c *i2c) { u8 cr; xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); /* Disable IIC Device. */ cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK); } static void xiic_read_rx(struct xiic_i2c *i2c) { u8 bytes_in_fifo; int i; bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1; dev_dbg(i2c->adap.dev.parent, "%s entry, bytes in fifo: %d, msg: %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); for (i = 0; i < bytes_in_fifo; i++) i2c->rx_msg->buf[i2c->rx_pos++] = xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ? IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1); } static int xiic_tx_fifo_space(struct xiic_i2c *i2c) { /* return the actual space left in the FIFO */ return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1; } static void xiic_fill_tx_fifo(struct xiic_i2c *i2c) { u8 fifo_space = xiic_tx_fifo_space(i2c); int len = xiic_tx_space(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); while (len--) { u16 data = i2c->tx_msg->buf[i2c->tx_pos++]; if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) { /* last message in transfer -> STOP */ data |= XIIC_TX_DYN_STOP_MASK; dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); } xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); } } static void xiic_wakeup(struct xiic_i2c *i2c, int code) { i2c->tx_msg = NULL; i2c->rx_msg = NULL; i2c->nmsgs = 0; i2c->state = code; wake_up(&i2c->wait); } static irqreturn_t xiic_process(int irq, void *dev_id) { struct xiic_i2c *i2c = dev_id; u32 pend, isr, ier; u32 clr = 0; int xfer_more = 0; int wakeup_req = 0; int wakeup_code = 0; /* Get the interrupt Status from the IPIF. There is no clearing of * interrupts in the IPIF. Interrupts must be cleared at the source. * To find which interrupts are pending; AND interrupts pending with * interrupts masked. */ mutex_lock(&i2c->lock); isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); pend = isr & ier; dev_dbg(i2c->adap.dev.parent, "%s: IER: 0x%x, ISR: 0x%x, pend: 0x%x\n", __func__, ier, isr, pend); dev_dbg(i2c->adap.dev.parent, "%s: SR: 0x%x, msg: %p, nmsgs: %d\n", __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), i2c->tx_msg, i2c->nmsgs); /* Service requesting interrupt */ if ((pend & XIIC_INTR_ARB_LOST_MASK) || ((pend & XIIC_INTR_TX_ERROR_MASK) && !(pend & XIIC_INTR_RX_FULL_MASK))) { /* bus arbritration lost, or... * Transmit error _OR_ RX completed * if this happens when RX_FULL is not set * this is probably a TX error */ dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__); /* dynamic mode seem to suffer from problems if we just flushes * fifos and the next message is a TX with len 0 (only addr) * reset the IP instead of just flush fifos */ xiic_reinit(i2c); if (i2c->rx_msg) { wakeup_req = 1; wakeup_code = STATE_ERROR; } if (i2c->tx_msg) { wakeup_req = 1; wakeup_code = STATE_ERROR; } /* don't try to handle other events */ goto out; } if (pend & XIIC_INTR_RX_FULL_MASK) { /* Receive register/FIFO is full */ clr |= XIIC_INTR_RX_FULL_MASK; if (!i2c->rx_msg) { dev_dbg(i2c->adap.dev.parent, "%s unexpected RX IRQ\n", __func__); xiic_clear_rx_fifo(i2c); goto out; } xiic_read_rx(i2c); if (xiic_rx_space(i2c) == 0) { /* this is the last part of the message */ i2c->rx_msg = NULL; /* also clear TX error if there (RX complete) */ clr |= (isr & XIIC_INTR_TX_ERROR_MASK); dev_dbg(i2c->adap.dev.parent, "%s end of message, nmsgs: %d\n", __func__, i2c->nmsgs); /* send next message if this wasn't the last, * otherwise the transfer will be finialise when * receiving the bus not busy interrupt */ if (i2c->nmsgs > 1) { i2c->nmsgs--; i2c->tx_msg++; dev_dbg(i2c->adap.dev.parent, "%s will start next...\n", __func__); xfer_more = 1; } } } if (pend & XIIC_INTR_BNB_MASK) { /* IIC bus has transitioned to not busy */ clr |= XIIC_INTR_BNB_MASK; /* The bus is not busy, disable BusNotBusy interrupt */ xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK); if (!i2c->tx_msg) goto out; wakeup_req = 1; if (i2c->nmsgs == 1 && !i2c->rx_msg && xiic_tx_space(i2c) == 0) wakeup_code = STATE_DONE; else wakeup_code = STATE_ERROR; } if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) { /* Transmit register/FIFO is empty or ½ empty */ clr |= (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)); if (!i2c->tx_msg) { dev_dbg(i2c->adap.dev.parent, "%s unexpected TX IRQ\n", __func__); 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) { dev_dbg(i2c->adap.dev.parent, "%s end of message sent, nmsgs: %d\n", __func__, i2c->nmsgs); if (i2c->nmsgs > 1) { i2c->nmsgs--; i2c->tx_msg++; xfer_more = 1; } else { xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); dev_dbg(i2c->adap.dev.parent, "%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); } out: dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr); xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr); if (xfer_more) __xiic_start_xfer(i2c); if (wakeup_req) xiic_wakeup(i2c, wakeup_code); WARN_ON(xfer_more && wakeup_req); mutex_unlock(&i2c->lock); return IRQ_HANDLED; } static int xiic_bus_busy(struct xiic_i2c *i2c) { u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET); return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0; } static int xiic_busy(struct xiic_i2c *i2c) { int tries = 3; int err; if (i2c->tx_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); err = xiic_bus_busy(i2c); } return err; } static void xiic_start_recv(struct xiic_i2c *i2c) { u8 rx_watermark; struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg; unsigned long flags; /* Clear and enable Rx full interrupt. */ xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK); /* we want to get all but last byte, because the TX_ERROR IRQ is used * to inidicate error ACK on the address, and negative ack on the last * received byte, so to not mix them receive all but last. * In the case where there is only one byte to receive * we can check if ERROR and RX full is set at the same time */ rx_watermark = msg->len; if (rx_watermark > IIC_RX_FIFO_DEPTH) rx_watermark = IIC_RX_FIFO_DEPTH; xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1); local_irq_save(flags); if (!(msg->flags & I2C_M_NOSTART)) /* write the address */ xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, i2c_8bit_addr_from_msg(msg) | XIIC_TX_DYN_START_MASK); xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0)); local_irq_restore(flags); if (i2c->nmsgs == 1) /* very last, enable bus not busy as well */ xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); /* the message is tx:ed */ i2c->tx_pos = msg->len; } static void xiic_start_send(struct xiic_i2c *i2c) { struct i2c_msg *msg = i2c->tx_msg; xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK); 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 (!(msg->flags & I2C_M_NOSTART)) { /* write the address */ u16 data = i2c_8bit_addr_from_msg(msg) | XIIC_TX_DYN_START_MASK; if ((i2c->nmsgs == 1) && msg->len == 0) /* no data and last message -> add STOP */ data |= XIIC_TX_DYN_STOP_MASK; xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); } xiic_fill_tx_fifo(i2c); /* Clear any pending Tx empty, Tx Error and then enable them. */ xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_BNB_MASK); } static irqreturn_t xiic_isr(int irq, void *dev_id) { struct xiic_i2c *i2c = dev_id; u32 pend, isr, ier; irqreturn_t ret = IRQ_NONE; /* Do not processes a devices interrupts if the device has no * interrupts pending */ dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__); isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); pend = isr & ier; if (pend) ret = IRQ_WAKE_THREAD; return ret; } static void __xiic_start_xfer(struct xiic_i2c *i2c) { int first = 1; 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->tx_msg) return; i2c->rx_pos = 0; i2c->tx_pos = 0; i2c->state = STATE_START; while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) { if (!first) { i2c->nmsgs--; i2c->tx_msg++; i2c->tx_pos = 0; } else first = 0; if (i2c->tx_msg->flags & I2C_M_RD) { /* we dont date putting several reads in the FIFO */ xiic_start_recv(i2c); return; } else { xiic_start_send(i2c); if (xiic_tx_space(i2c) != 0) { /* the message could not be completely sent */ break; } } fifo_space = xiic_tx_fifo_space(i2c); } /* there are more messages or the current one could not be completely * put into the FIFO, also enable the half empty interrupt */ if (i2c->nmsgs > 1 || xiic_tx_space(i2c)) xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK); } static int xiic_start_xfer(struct xiic_i2c *i2c) { int ret; mutex_lock(&i2c->lock); ret = xiic_reinit(i2c); if (!ret) __xiic_start_xfer(i2c); mutex_unlock(&i2c->lock); return ret; } static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct xiic_i2c *i2c = i2c_get_adapdata(adap); int err; dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)); err = pm_runtime_resume_and_get(i2c->dev); if (err < 0) return err; err = xiic_busy(i2c); if (err) goto out; i2c->tx_msg = msgs; i2c->nmsgs = num; err = xiic_start_xfer(i2c); if (err < 0) { dev_err(adap->dev.parent, "Error xiic_start_xfer\n"); goto out; } if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || (i2c->state == STATE_DONE), HZ)) { err = (i2c->state == STATE_DONE) ? num : -EIO; goto out; } else { i2c->tx_msg = NULL; i2c->rx_msg = NULL; i2c->nmsgs = 0; err = -ETIMEDOUT; goto out; } out: pm_runtime_mark_last_busy(i2c->dev); pm_runtime_put_autosuspend(i2c->dev); return err; } static u32 xiic_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm xiic_algorithm = { .master_xfer = xiic_xfer, .functionality = xiic_func, }; static const struct i2c_adapter_quirks xiic_quirks = { .max_read_len = 255, }; static const struct i2c_adapter xiic_adapter = { .owner = THIS_MODULE, .class = I2C_CLASS_DEPRECATED, .algo = &xiic_algorithm, .quirks = &xiic_quirks, }; static int xiic_i2c_probe(struct platform_device *pdev) { struct xiic_i2c *i2c; struct xiic_i2c_platform_data *pdata; struct resource *res; int ret, irq; u8 i; u32 sr; i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->base)) return PTR_ERR(i2c->base); irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; pdata = dev_get_platdata(&pdev->dev); /* hook up driver to tree */ platform_set_drvdata(pdev, i2c); i2c->adap = xiic_adapter; i2c_set_adapdata(&i2c->adap, i2c); i2c->adap.dev.parent = &pdev->dev; i2c->adap.dev.of_node = pdev->dev.of_node; snprintf(i2c->adap.name, sizeof(i2c->adap.name), DRIVER_NAME " %s", pdev->name); mutex_init(&i2c->lock); init_waitqueue_head(&i2c->wait); i2c->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(i2c->clk)) { if (PTR_ERR(i2c->clk) != -EPROBE_DEFER) dev_err(&pdev->dev, "input clock not found.\n"); return PTR_ERR(i2c->clk); } ret = clk_prepare_enable(i2c->clk); if (ret) { dev_err(&pdev->dev, "Unable to enable clock.\n"); return ret; } i2c->dev = &pdev->dev; pm_runtime_set_autosuspend_delay(i2c->dev, XIIC_PM_TIMEOUT); pm_runtime_use_autosuspend(i2c->dev); pm_runtime_set_active(i2c->dev); pm_runtime_enable(i2c->dev); ret = devm_request_threaded_irq(&pdev->dev, irq, xiic_isr, xiic_process, IRQF_ONESHOT, pdev->name, i2c); if (ret < 0) { dev_err(&pdev->dev, "Cannot claim IRQ\n"); goto err_clk_dis; } i2c->singlemaster = of_property_read_bool(pdev->dev.of_node, "single-master"); /* * Detect endianness * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not * set, assume that the endianness was wrong and swap. */ i2c->endianness = LITTLE; xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); /* Reset is cleared in xiic_reinit */ sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET); if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK)) i2c->endianness = BIG; ret = xiic_reinit(i2c); if (ret < 0) { dev_err(&pdev->dev, "Cannot xiic_reinit\n"); goto err_clk_dis; } /* add i2c adapter to i2c tree */ ret = i2c_add_adapter(&i2c->adap); if (ret) { xiic_deinit(i2c); goto err_clk_dis; } if (pdata) { /* add in known devices to the bus */ for (i = 0; i < pdata->num_devices; i++) i2c_new_client_device(&i2c->adap, pdata->devices + i); } return 0; err_clk_dis: pm_runtime_set_suspended(&pdev->dev); pm_runtime_disable(&pdev->dev); clk_disable_unprepare(i2c->clk); return ret; } static int xiic_i2c_remove(struct platform_device *pdev) { struct xiic_i2c *i2c = platform_get_drvdata(pdev); int ret; /* remove adapter & data */ i2c_del_adapter(&i2c->adap); ret = pm_runtime_resume_and_get(i2c->dev); if (ret < 0) return ret; xiic_deinit(i2c); pm_runtime_put_sync(i2c->dev); clk_disable_unprepare(i2c->clk); pm_runtime_disable(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); pm_runtime_dont_use_autosuspend(&pdev->dev); return 0; } #if defined(CONFIG_OF) static const struct of_device_id xiic_of_match[] = { { .compatible = "xlnx,xps-iic-2.00.a", }, {}, }; MODULE_DEVICE_TABLE(of, xiic_of_match); #endif 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) }; static struct platform_driver xiic_i2c_driver = { .probe = xiic_i2c_probe, .remove = xiic_i2c_remove, .driver = { .name = DRIVER_NAME, .of_match_table = of_match_ptr(xiic_of_match), .pm = &xiic_dev_pm_ops, }, }; module_platform_driver(xiic_i2c_driver); MODULE_ALIAS("platform:" DRIVER_NAME); MODULE_AUTHOR("info@mocean-labs.com"); MODULE_DESCRIPTION("Xilinx I2C bus driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:"DRIVER_NAME);