diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-xiic.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-xiic.c | 930 |
1 files changed, 930 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c new file mode 100644 index 000000000..b27bfc776 --- /dev/null +++ b/drivers/i2c/busses/i2c-xiic.c @@ -0,0 +1,930 @@ +// 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 <linux/kernel.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/completion.h> +#include <linux/platform_data/i2c-xiic.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/clk.h> +#include <linux/pm_runtime.h> + +#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 + * @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 + */ +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; +}; + +#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)) +/* 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_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) && 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, 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); + + + /* 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 < 0) + 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; + } + /* 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_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) + 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; + struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg; + + /* 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, (u8)(rx_watermark - 1)); + + 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)); + + 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; + + 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); + } + + /* 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); +} + +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) +{ + int ret; + + 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); + + 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 if (err < 0) { /* Completion error */ + i2c->tx_msg = NULL; + i2c->rx_msg = NULL; + i2c->nmsgs = 0; + } 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; +} + +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); + + i2c->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(i2c->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk), + "input clock not found.\n"); + + 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, NULL, + 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"); |