// 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" #define DYNAMIC_MODE_READ_BROKEN_BIT BIT(0) #define SMBUS_BLOCK_READ_MIN_LEN 3 enum xilinx_i2c_state { STATE_DONE, STATE_ERROR, STATE_START }; enum xiic_endian { LITTLE, BIG }; enum i2c_scl_freq { REG_VALUES_100KHZ = 0, REG_VALUES_400KHZ = 1, REG_VALUES_1MHZ = 2 }; /** * struct xiic_i2c - Internal representation of the XIIC I2C bus * @dev: Pointer to device structure * @base: Memory base of the HW registers * @completion: Completion 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 * @dynamic: Mode of controller * @prev_msg_tx: Previous message is Tx * @quirks: To hold platform specific bug info * @smbus_block_read: Flag to handle block read * @input_clk: Input clock to I2C controller * @i2c_clk: I2C SCL frequency */ struct xiic_i2c { struct device *dev; void __iomem *base; struct completion completion; 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; bool dynamic; bool prev_msg_tx; u32 quirks; bool smbus_block_read; unsigned long input_clk; unsigned int i2c_clk; }; struct xiic_version_data { u32 quirks; }; /** * struct timing_regs - AXI I2C timing registers that depend on I2C spec * @tsusta: setup time for a repeated START condition * @tsusto: setup time for a STOP condition * @thdsta: hold time for a repeated START condition * @tsudat: setup time for data * @tbuf: bus free time between STOP and START */ struct timing_regs { unsigned int tsusta; unsigned int tsusto; unsigned int thdsta; unsigned int tsudat; unsigned int tbuf; }; /* Reg values in ns derived from I2C spec and AXI I2C PG for different frequencies */ static const struct timing_regs timing_reg_values[] = { { 5700, 5000, 4300, 550, 5000 }, /* Reg values for 100KHz */ { 900, 900, 900, 400, 1600 }, /* Reg values for 400KHz */ { 380, 380, 380, 170, 620 }, /* Reg values for 1MHz */ }; #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 */ /* * Timing register offsets from RegisterBase. These are used only for * setting i2c clock frequency for the line. */ #define XIIC_TSUSTA_REG_OFFSET (0x28 + XIIC_REG_OFFSET) /* TSUSTA Register */ #define XIIC_TSUSTO_REG_OFFSET (0x2C + XIIC_REG_OFFSET) /* TSUSTO Register */ #define XIIC_THDSTA_REG_OFFSET (0x30 + XIIC_REG_OFFSET) /* THDSTA Register */ #define XIIC_TSUDAT_REG_OFFSET (0x34 + XIIC_REG_OFFSET) /* TSUDAT Register */ #define XIIC_TBUF_REG_OFFSET (0x38 + XIIC_REG_OFFSET) /* TBUF Register */ #define XIIC_THIGH_REG_OFFSET (0x3C + XIIC_REG_OFFSET) /* THIGH Register */ #define XIIC_TLOW_REG_OFFSET (0x40 + XIIC_REG_OFFSET) /* TLOW Register */ #define XIIC_THDDAT_REG_OFFSET (0x44 + XIIC_REG_OFFSET) /* THDDAT 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 */ /* Dynamic mode constants */ #define MAX_READ_LENGTH_DYNAMIC 255 /* Max length for dynamic read */ /* * 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)) /* timeout waiting for the controller finish transfers */ #define XIIC_XFER_TIMEOUT (msecs_to_jiffies(10000)) /* * 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, struct i2c_msg *msgs, int num); 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_wait_tx_empty(struct xiic_i2c *i2c) { u8 isr; unsigned long timeout; timeout = jiffies + XIIC_I2C_TIMEOUT; for (isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); !(isr & XIIC_INTR_TX_EMPTY_MASK); isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET)) { if (time_after(jiffies, timeout)) { dev_err(i2c->dev, "Timeout waiting at Tx empty\n"); return -ETIMEDOUT; } } return 0; } /** * xiic_setclk - Sets the configured clock rate * @i2c: Pointer to the xiic device structure * * The timing register values are calculated according to the input clock * frequency and configured scl frequency. For details, please refer the * AXI I2C PG and NXP I2C Spec. * Supported frequencies are 100KHz, 400KHz and 1MHz. * * Return: 0 on success (Supported frequency selected or not configurable in SW) * -EINVAL on failure (scl frequency not supported or THIGH is 0) */ static int xiic_setclk(struct xiic_i2c *i2c) { unsigned int clk_in_mhz; 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 not specified in DT, do not configure in SW. Rely only on Vivado design */ if (!i2c->i2c_clk || !i2c->input_clk) return 0; clk_in_mhz = DIV_ROUND_UP(i2c->input_clk, 1000000); switch (i2c->i2c_clk) { case I2C_MAX_FAST_MODE_PLUS_FREQ: index = REG_VALUES_1MHZ; break; case I2C_MAX_FAST_MODE_FREQ: index = REG_VALUES_400KHZ; break; case I2C_MAX_STANDARD_MODE_FREQ: index = REG_VALUES_100KHZ; break; default: dev_warn(i2c->adap.dev.parent, "Unsupported scl frequency\n"); return -EINVAL; } /* * Value to be stored in a register is the number of clock cycles required * for the time duration. So the time is divided by the input clock time * period to get the number of clock cycles required. Refer Xilinx AXI I2C * PG document and I2C specification for further details. */ /* THIGH - Depends on SCL clock frequency(i2c_clk) as below */ reg_val = (DIV_ROUND_UP(i2c->input_clk, 2 * i2c->i2c_clk)) - 7; if (reg_val == 0) return -EINVAL; xiic_setreg32(i2c, XIIC_THIGH_REG_OFFSET, reg_val - 1); /* TLOW - Value same as THIGH */ xiic_setreg32(i2c, XIIC_TLOW_REG_OFFSET, reg_val - 1); /* TSUSTA */ reg_val = (timing_reg_values[index].tsusta * clk_in_mhz) / 1000; xiic_setreg32(i2c, XIIC_TSUSTA_REG_OFFSET, reg_val - 1); /* TSUSTO */ reg_val = (timing_reg_values[index].tsusto * clk_in_mhz) / 1000; xiic_setreg32(i2c, XIIC_TSUSTO_REG_OFFSET, reg_val - 1); /* THDSTA */ reg_val = (timing_reg_values[index].thdsta * clk_in_mhz) / 1000; xiic_setreg32(i2c, XIIC_THDSTA_REG_OFFSET, reg_val - 1); /* TSUDAT */ reg_val = (timing_reg_values[index].tsudat * clk_in_mhz) / 1000; xiic_setreg32(i2c, XIIC_TSUDAT_REG_OFFSET, reg_val - 1); /* TBUF */ reg_val = (timing_reg_values[index].tbuf * clk_in_mhz) / 1000; xiic_setreg32(i2c, XIIC_TBUF_REG_OFFSET, reg_val - 1); /* THDDAT */ xiic_setreg32(i2c, XIIC_THDDAT_REG_OFFSET, 1); return 0; } static int xiic_reinit(struct xiic_i2c *i2c) { int ret; xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); ret = xiic_setclk(i2c); if (ret) return ret; /* 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_smbus_block_read_setup(struct xiic_i2c *i2c) { u8 rxmsg_len, rfd_set = 0; /* * Clear the I2C_M_RECV_LEN flag to avoid setting * message length again */ i2c->rx_msg->flags &= ~I2C_M_RECV_LEN; /* Set smbus_block_read flag to identify in isr */ i2c->smbus_block_read = true; /* Read byte from rx fifo and set message length */ rxmsg_len = xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); i2c->rx_msg->buf[i2c->rx_pos++] = rxmsg_len; /* Check if received length is valid */ if (rxmsg_len <= I2C_SMBUS_BLOCK_MAX) { /* Set Receive fifo depth */ if (rxmsg_len > IIC_RX_FIFO_DEPTH) { /* * When Rx msg len greater than or equal to Rx fifo capacity * Receive fifo depth should set to Rx fifo capacity minus 1 */ rfd_set = IIC_RX_FIFO_DEPTH - 1; i2c->rx_msg->len = rxmsg_len + 1; } else if ((rxmsg_len == 1) || (rxmsg_len == 0)) { /* * Minimum of 3 bytes required to exit cleanly. 1 byte * already received, Second byte is being received. Have * to set NACK in read_rx before receiving the last byte */ rfd_set = 0; i2c->rx_msg->len = SMBUS_BLOCK_READ_MIN_LEN; } else { /* * When Rx msg len less than Rx fifo capacity * Receive fifo depth should set to Rx msg len minus 2 */ rfd_set = rxmsg_len - 2; i2c->rx_msg->len = rxmsg_len + 1; } xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rfd_set); return; } /* Invalid message length, trigger STATE_ERROR with tx_msg_len in ISR */ i2c->tx_msg->len = 3; i2c->smbus_block_read = false; dev_err(i2c->adap.dev.parent, "smbus_block_read Invalid msg length\n"); } static void xiic_read_rx(struct xiic_i2c *i2c) { u8 bytes_in_fifo, cr = 0, bytes_to_read = 0; u32 bytes_rem = 0; 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, 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); bytes_to_read = bytes_in_fifo; if (!i2c->dynamic) { bytes_rem = xiic_rx_space(i2c) - bytes_in_fifo; /* Set msg length if smbus_block_read */ if (i2c->rx_msg->flags & I2C_M_RECV_LEN) { xiic_smbus_block_read_setup(i2c); return; } if (bytes_rem > IIC_RX_FIFO_DEPTH) { bytes_to_read = bytes_in_fifo; } else if (bytes_rem > 1) { bytes_to_read = bytes_rem - 1; } else if (bytes_rem == 1) { bytes_to_read = 1; /* Set NACK in CR to indicate slave transmitter */ cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr | XIIC_CR_NO_ACK_MASK); } else if (bytes_rem == 0) { bytes_to_read = bytes_in_fifo; /* Generate stop on the bus if it is last message */ if (i2c->nmsgs == 1) { cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_MSMS_MASK); } /* Make TXACK=0, clean up for next transaction */ cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_NO_ACK_MASK); } } /* Read the fifo */ for (i = 0; i < bytes_to_read; i++) { i2c->rx_msg->buf[i2c->rx_pos++] = xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); } if (i2c->dynamic) { u8 bytes; /* Receive remaining bytes if less than fifo depth */ bytes = min_t(u8, xiic_rx_space(i2c), IIC_RX_FIFO_DEPTH); bytes--; xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, bytes); } } 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) && 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); } 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, enum xilinx_i2c_state code) { i2c->tx_msg = NULL; i2c->rx_msg = NULL; i2c->nmsgs = 0; i2c->state = code; complete(&i2c->completion); } 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; enum xilinx_i2c_state wakeup_code = STATE_DONE; int ret; /* 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); dev_dbg(i2c->adap.dev.parent, "%s, ISR: 0x%x, CR: 0x%x\n", __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); /* 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 */ ret = xiic_reinit(i2c); if (!ret) dev_dbg(i2c->adap.dev.parent, "reinit failed\n"); if (i2c->rx_msg) { wakeup_req = 1; wakeup_code = STATE_ERROR; } if (i2c->tx_msg) { wakeup_req = 1; wakeup_code = STATE_ERROR; } } 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_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); } 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 && i2c->smbus_block_read) { i2c->smbus_block_read = false; /* Set requested message len=1 to indicate STATE_DONE */ i2c->tx_msg->len = 1; } 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; } 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 || 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); err = xiic_bus_busy(i2c); } return err; } 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)); /* Disable Tx interrupts */ xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK | XIIC_INTR_TX_EMPTY_MASK); if (i2c->dynamic) { u8 bytes; u16 val; /* 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 indicate 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; bytes = min_t(u8, rx_watermark, IIC_RX_FIFO_DEPTH); if (rx_watermark > 0) bytes--; xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, bytes); /* write the address */ xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, i2c_8bit_addr_from_msg(msg) | XIIC_TX_DYN_START_MASK); /* If last message, include dynamic stop bit with length */ val = (i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0; val |= msg->len; xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, val); xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); } else { /* * If previous message is Tx, make sure that Tx FIFO is empty * before starting a new transfer as the repeated start in * standard mode can corrupt the transaction if there are * still bytes to be transmitted in FIFO */ if (i2c->prev_msg_tx) { int status; status = xiic_wait_tx_empty(i2c); if (status) return; } cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); /* Set Receive fifo depth */ rx_watermark = msg->len; if (rx_watermark > IIC_RX_FIFO_DEPTH) { rfd_set = IIC_RX_FIFO_DEPTH - 1; } else if (rx_watermark == 1) { rfd_set = rx_watermark - 1; /* Set No_ACK, except for smbus_block_read */ if (!(i2c->rx_msg->flags & I2C_M_RECV_LEN)) { /* Handle single byte transfer separately */ cr |= XIIC_CR_NO_ACK_MASK; } } else if (rx_watermark == 0) { rfd_set = rx_watermark; } else { rfd_set = rx_watermark - 2; } /* Check if RSTA should be set */ if (cr & XIIC_CR_MSMS_MASK) { /* Already a master, RSTA should be set */ xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, (cr | XIIC_CR_REPEATED_START_MASK) & ~(XIIC_CR_DIR_IS_TX_MASK)); } xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rfd_set); /* Clear and enable Rx full and transmit complete interrupts */ xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK); /* Write the address */ xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, i2c_8bit_addr_from_msg(msg)); /* Write to Control Register,to start transaction in Rx mode */ if ((cr & XIIC_CR_MSMS_MASK) == 0) { xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, (cr | 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->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; /* Enable interrupts */ xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); i2c->prev_msg_tx = false; } static void xiic_start_send(struct xiic_i2c *i2c) { u8 cr = 0; 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->dynamic) { /* write the address */ 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); /* 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 | ((i2c->nmsgs > 1 || xiic_tx_space(i2c)) ? XIIC_INTR_TX_HALF_MASK : 0)); xiic_fill_tx_fifo(i2c); } else { /* * If previous message is Tx, make sure that Tx FIFO is empty * before starting a new transfer as the repeated start in * standard mode can corrupt the transaction if there are * still bytes to be transmitted in FIFO */ if (i2c->prev_msg_tx) { int status; status = xiic_wait_tx_empty(i2c); if (status) return; } /* Check if RSTA should be set */ cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); if (cr & XIIC_CR_MSMS_MASK) { /* Already a master, RSTA should be set */ xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, (cr | XIIC_CR_REPEATED_START_MASK | XIIC_CR_DIR_IS_TX_MASK) & ~(XIIC_CR_NO_ACK_MASK)); } /* Write address to FIFO */ data = i2c_8bit_addr_from_msg(msg); xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); /* Fill fifo */ xiic_fill_tx_fifo(i2c); if ((cr & XIIC_CR_MSMS_MASK) == 0) { /* Start Tx by writing to CR */ cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr | XIIC_CR_MSMS_MASK | XIIC_CR_DIR_IS_TX_MASK); } /* 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); } i2c->prev_msg_tx = true; } 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->tx_msg) return; i2c->rx_pos = 0; i2c->tx_pos = 0; i2c->state = STATE_START; if (i2c->tx_msg->flags & I2C_M_RD) { /* we dont date putting several reads in the FIFO */ xiic_start_recv(i2c); } else { xiic_start_send(i2c); } } 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); ret = xiic_busy(i2c); if (ret) goto out; i2c->tx_msg = msgs; i2c->rx_msg = NULL; i2c->nmsgs = num; init_completion(&i2c->completion); /* Decide standard mode or Dynamic mode */ i2c->dynamic = true; /* Initialize prev message type */ i2c->prev_msg_tx = false; /* * Scan through nmsgs, use dynamic mode when none of the below three * conditions occur. We need standard mode even if one condition holds * true in the entire array of messages in a single transfer. * If read transaction as dynamic mode is broken for delayed reads * in xlnx,axi-iic-2.0 / xlnx,xps-iic-2.00.a IP versions. * If read length is > 255 bytes. * If smbus_block_read transaction. */ for (count = 0; count < i2c->nmsgs; count++) { broken_read = (i2c->quirks & DYNAMIC_MODE_READ_BROKEN_BIT) && (i2c->tx_msg[count].flags & I2C_M_RD); max_read_len = (i2c->tx_msg[count].flags & I2C_M_RD) && (i2c->tx_msg[count].len > MAX_READ_LENGTH_DYNAMIC); smbus_blk_read = (i2c->tx_msg[count].flags & I2C_M_RECV_LEN); if (broken_read || max_read_len || smbus_blk_read) { i2c->dynamic = false; break; } } ret = xiic_reinit(i2c); if (!ret) __xiic_start_xfer(i2c); out: 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_start_xfer(i2c, msgs, num); if (err < 0) { dev_err(adap->dev.parent, "Error xiic_start_xfer\n"); goto out; } err = wait_for_completion_timeout(&i2c->completion, XIIC_XFER_TIMEOUT); mutex_lock(&i2c->lock); if (err == 0) { /* Timeout */ i2c->tx_msg = NULL; i2c->rx_msg = NULL; i2c->nmsgs = 0; err = -ETIMEDOUT; } else { err = (i2c->state == STATE_DONE) ? num : -EIO; } mutex_unlock(&i2c->lock); 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 | I2C_FUNC_SMBUS_BLOCK_DATA; } static const struct i2c_algorithm xiic_algorithm = { .master_xfer = xiic_xfer, .functionality = xiic_func, }; static const struct i2c_adapter xiic_adapter = { .owner = THIS_MODULE, .class = I2C_CLASS_DEPRECATED, .algo = &xiic_algorithm, }; #if defined(CONFIG_OF) static const struct xiic_version_data xiic_2_00 = { .quirks = DYNAMIC_MODE_READ_BROKEN_BIT, }; static const struct of_device_id xiic_of_match[] = { { .compatible = "xlnx,xps-iic-2.00.a", .data = &xiic_2_00 }, { .compatible = "xlnx,axi-iic-2.1", }, {}, }; MODULE_DEVICE_TABLE(of, xiic_of_match); #endif static int xiic_i2c_probe(struct platform_device *pdev) { struct xiic_i2c *i2c; struct xiic_i2c_platform_data *pdata; const struct of_device_id *match; struct resource *res; int ret, irq; u8 i; u32 sr; i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; match = of_match_node(xiic_of_match, pdev->dev.of_node); if (match && match->data) { const struct xiic_version_data *data = match->data; i2c->quirks = data->quirks; } i2c->base = devm_platform_get_and_ioremap_resource(pdev, 0, &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); i2c->clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(i2c->clk)) return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk), "failed to enable input clock.\n"); 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); /* SCL frequency configuration */ i2c->input_clk = clk_get_rate(i2c->clk); ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", &i2c->i2c_clk); /* If clock-frequency not specified in DT, do not configure in SW */ if (ret || i2c->i2c_clk > I2C_MAX_FAST_MODE_PLUS_FREQ) i2c->i2c_clk = 0; ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, xiic_process, IRQF_ONESHOT, pdev->name, i2c); if (ret < 0) { dev_err(&pdev->dev, "Cannot claim IRQ\n"); goto err_pm_disable; } 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_pm_disable; } /* add i2c adapter to i2c tree */ ret = i2c_add_adapter(&i2c->adap); if (ret) { xiic_deinit(i2c); goto err_pm_disable; } 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); } dev_dbg(&pdev->dev, "mmio %08lx irq %d scl clock frequency %d\n", (unsigned long)res->start, irq, i2c->i2c_clk); return 0; err_pm_disable: pm_runtime_set_suspended(&pdev->dev); pm_runtime_disable(&pdev->dev); return ret; } static void 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_get_sync(i2c->dev); if (ret < 0) dev_warn(&pdev->dev, "Failed to activate device for removal (%pe)\n", ERR_PTR(ret)); else xiic_deinit(i2c); pm_runtime_put_sync(i2c->dev); pm_runtime_disable(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); 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) }; static struct platform_driver xiic_i2c_driver = { .probe = xiic_i2c_probe, .remove_new = 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");