diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-cadence.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-cadence.c | 1447 |
1 files changed, 1447 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c new file mode 100644 index 0000000000..de3f58b60d --- /dev/null +++ b/drivers/i2c/busses/i2c-cadence.c @@ -0,0 +1,1447 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * I2C bus driver for the Cadence I2C controller. + * + * Copyright (C) 2009 - 2014 Xilinx, Inc. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/pm_runtime.h> +#include <linux/pinctrl/consumer.h> +#include <linux/reset.h> + +/* Register offsets for the I2C device. */ +#define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */ +#define CDNS_I2C_SR_OFFSET 0x04 /* Status Register, RO */ +#define CDNS_I2C_ADDR_OFFSET 0x08 /* I2C Address Register, RW */ +#define CDNS_I2C_DATA_OFFSET 0x0C /* I2C Data Register, RW */ +#define CDNS_I2C_ISR_OFFSET 0x10 /* IRQ Status Register, RW */ +#define CDNS_I2C_XFER_SIZE_OFFSET 0x14 /* Transfer Size Register, RW */ +#define CDNS_I2C_TIME_OUT_OFFSET 0x1C /* Time Out Register, RW */ +#define CDNS_I2C_IMR_OFFSET 0x20 /* IRQ Mask Register, RO */ +#define CDNS_I2C_IER_OFFSET 0x24 /* IRQ Enable Register, WO */ +#define CDNS_I2C_IDR_OFFSET 0x28 /* IRQ Disable Register, WO */ + +/* Control Register Bit mask definitions */ +#define CDNS_I2C_CR_HOLD BIT(4) /* Hold Bus bit */ +#define CDNS_I2C_CR_ACK_EN BIT(3) +#define CDNS_I2C_CR_NEA BIT(2) +#define CDNS_I2C_CR_MS BIT(1) +/* Read or Write Master transfer 0 = Transmitter, 1 = Receiver */ +#define CDNS_I2C_CR_RW BIT(0) +/* 1 = Auto init FIFO to zeroes */ +#define CDNS_I2C_CR_CLR_FIFO BIT(6) +#define CDNS_I2C_CR_DIVA_SHIFT 14 +#define CDNS_I2C_CR_DIVA_MASK (3 << CDNS_I2C_CR_DIVA_SHIFT) +#define CDNS_I2C_CR_DIVB_SHIFT 8 +#define CDNS_I2C_CR_DIVB_MASK (0x3f << CDNS_I2C_CR_DIVB_SHIFT) + +#define CDNS_I2C_CR_MASTER_EN_MASK (CDNS_I2C_CR_NEA | \ + CDNS_I2C_CR_ACK_EN | \ + CDNS_I2C_CR_MS) + +#define CDNS_I2C_CR_SLAVE_EN_MASK ~CDNS_I2C_CR_MASTER_EN_MASK + +/* Status Register Bit mask definitions */ +#define CDNS_I2C_SR_BA BIT(8) +#define CDNS_I2C_SR_TXDV BIT(6) +#define CDNS_I2C_SR_RXDV BIT(5) +#define CDNS_I2C_SR_RXRW BIT(3) + +/* + * I2C Address Register Bit mask definitions + * Normal addressing mode uses [6:0] bits. Extended addressing mode uses [9:0] + * bits. A write access to this register always initiates a transfer if the I2C + * is in master mode. + */ +#define CDNS_I2C_ADDR_MASK 0x000003FF /* I2C Address Mask */ + +/* + * I2C Interrupt Registers Bit mask definitions + * All the four interrupt registers (Status/Mask/Enable/Disable) have the same + * bit definitions. + */ +#define CDNS_I2C_IXR_ARB_LOST BIT(9) +#define CDNS_I2C_IXR_RX_UNF BIT(7) +#define CDNS_I2C_IXR_TX_OVF BIT(6) +#define CDNS_I2C_IXR_RX_OVF BIT(5) +#define CDNS_I2C_IXR_SLV_RDY BIT(4) +#define CDNS_I2C_IXR_TO BIT(3) +#define CDNS_I2C_IXR_NACK BIT(2) +#define CDNS_I2C_IXR_DATA BIT(1) +#define CDNS_I2C_IXR_COMP BIT(0) + +#define CDNS_I2C_IXR_ALL_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ + CDNS_I2C_IXR_RX_UNF | \ + CDNS_I2C_IXR_TX_OVF | \ + CDNS_I2C_IXR_RX_OVF | \ + CDNS_I2C_IXR_SLV_RDY | \ + CDNS_I2C_IXR_TO | \ + CDNS_I2C_IXR_NACK | \ + CDNS_I2C_IXR_DATA | \ + CDNS_I2C_IXR_COMP) + +#define CDNS_I2C_IXR_ERR_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ + CDNS_I2C_IXR_RX_UNF | \ + CDNS_I2C_IXR_TX_OVF | \ + CDNS_I2C_IXR_RX_OVF | \ + CDNS_I2C_IXR_NACK) + +#define CDNS_I2C_ENABLED_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \ + CDNS_I2C_IXR_RX_UNF | \ + CDNS_I2C_IXR_TX_OVF | \ + CDNS_I2C_IXR_RX_OVF | \ + CDNS_I2C_IXR_NACK | \ + CDNS_I2C_IXR_DATA | \ + CDNS_I2C_IXR_COMP) + +#define CDNS_I2C_IXR_SLAVE_INTR_MASK (CDNS_I2C_IXR_RX_UNF | \ + CDNS_I2C_IXR_TX_OVF | \ + CDNS_I2C_IXR_RX_OVF | \ + CDNS_I2C_IXR_TO | \ + CDNS_I2C_IXR_NACK | \ + CDNS_I2C_IXR_DATA | \ + CDNS_I2C_IXR_COMP) + +#define CDNS_I2C_TIMEOUT msecs_to_jiffies(1000) +/* timeout for pm runtime autosuspend */ +#define CNDS_I2C_PM_TIMEOUT 1000 /* ms */ + +#define CDNS_I2C_FIFO_DEPTH_DEFAULT 16 +#define CDNS_I2C_MAX_TRANSFER_SIZE 255 +/* Transfer size in multiples of data interrupt depth */ +#define CDNS_I2C_TRANSFER_SIZE(max) ((max) - 3) + +#define DRIVER_NAME "cdns-i2c" + +#define CDNS_I2C_DIVA_MAX 4 +#define CDNS_I2C_DIVB_MAX 64 + +#define CDNS_I2C_TIMEOUT_MAX 0xFF + +#define CDNS_I2C_BROKEN_HOLD_BIT BIT(0) +#define CDNS_I2C_POLL_US 100000 +#define CDNS_I2C_TIMEOUT_US 500000 + +#define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset) +#define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset) + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +/** + * enum cdns_i2c_mode - I2C Controller current operating mode + * + * @CDNS_I2C_MODE_SLAVE: I2C controller operating in slave mode + * @CDNS_I2C_MODE_MASTER: I2C Controller operating in master mode + */ +enum cdns_i2c_mode { + CDNS_I2C_MODE_SLAVE, + CDNS_I2C_MODE_MASTER, +}; + +/** + * enum cdns_i2c_slave_state - Slave state when I2C is operating in slave mode + * + * @CDNS_I2C_SLAVE_STATE_IDLE: I2C slave idle + * @CDNS_I2C_SLAVE_STATE_SEND: I2C slave sending data to master + * @CDNS_I2C_SLAVE_STATE_RECV: I2C slave receiving data from master + */ +enum cdns_i2c_slave_state { + CDNS_I2C_SLAVE_STATE_IDLE, + CDNS_I2C_SLAVE_STATE_SEND, + CDNS_I2C_SLAVE_STATE_RECV, +}; +#endif + +/** + * struct cdns_i2c - I2C device private data structure + * + * @dev: Pointer to device structure + * @membase: Base address of the I2C device + * @adap: I2C adapter instance + * @p_msg: Message pointer + * @err_status: Error status in Interrupt Status Register + * @xfer_done: Transfer complete status + * @p_send_buf: Pointer to transmit buffer + * @p_recv_buf: Pointer to receive buffer + * @send_count: Number of bytes still expected to send + * @recv_count: Number of bytes still expected to receive + * @curr_recv_count: Number of bytes to be received in current transfer + * @input_clk: Input clock to I2C controller + * @i2c_clk: Maximum I2C clock speed + * @bus_hold_flag: Flag used in repeated start for clearing HOLD bit + * @clk: Pointer to struct clk + * @clk_rate_change_nb: Notifier block for clock rate changes + * @reset: Reset control for the device + * @quirks: flag for broken hold bit usage in r1p10 + * @ctrl_reg: Cached value of the control register. + * @rinfo: I2C GPIO recovery information + * @ctrl_reg_diva_divb: value of fields DIV_A and DIV_B from CR register + * @slave: Registered slave instance. + * @dev_mode: I2C operating role(master/slave). + * @slave_state: I2C Slave state(idle/read/write). + * @fifo_depth: The depth of the transfer FIFO + * @transfer_size: The maximum number of bytes in one transfer + */ +struct cdns_i2c { + struct device *dev; + void __iomem *membase; + struct i2c_adapter adap; + struct i2c_msg *p_msg; + int err_status; + struct completion xfer_done; + unsigned char *p_send_buf; + unsigned char *p_recv_buf; + unsigned int send_count; + unsigned int recv_count; + unsigned int curr_recv_count; + unsigned long input_clk; + unsigned int i2c_clk; + unsigned int bus_hold_flag; + struct clk *clk; + struct notifier_block clk_rate_change_nb; + struct reset_control *reset; + u32 quirks; + u32 ctrl_reg; + struct i2c_bus_recovery_info rinfo; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + u16 ctrl_reg_diva_divb; + struct i2c_client *slave; + enum cdns_i2c_mode dev_mode; + enum cdns_i2c_slave_state slave_state; +#endif + u32 fifo_depth; + unsigned int transfer_size; +}; + +struct cdns_platform_data { + u32 quirks; +}; + +#define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \ + clk_rate_change_nb) + +/** + * cdns_i2c_clear_bus_hold - Clear bus hold bit + * @id: Pointer to driver data struct + * + * Helper to clear the controller's bus hold bit. + */ +static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id) +{ + u32 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + if (reg & CDNS_I2C_CR_HOLD) + cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET); +} + +static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround) +{ + return (hold_wrkaround && + (id->curr_recv_count == id->fifo_depth + 1)); +} + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static void cdns_i2c_set_mode(enum cdns_i2c_mode mode, struct cdns_i2c *id) +{ + /* Disable all interrupts */ + cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET); + + /* Clear FIFO and transfer size */ + cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET); + + /* Update device mode and state */ + id->dev_mode = mode; + id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; + + switch (mode) { + case CDNS_I2C_MODE_MASTER: + /* Enable i2c master */ + cdns_i2c_writereg(id->ctrl_reg_diva_divb | + CDNS_I2C_CR_MASTER_EN_MASK, + CDNS_I2C_CR_OFFSET); + /* + * This delay is needed to give the IP some time to switch to + * the master mode. With lower values(like 110 us) i2cdetect + * will not detect any slave and without this delay, the IP will + * trigger a timeout interrupt. + */ + usleep_range(115, 125); + break; + case CDNS_I2C_MODE_SLAVE: + /* Enable i2c slave */ + cdns_i2c_writereg(id->ctrl_reg_diva_divb & + CDNS_I2C_CR_SLAVE_EN_MASK, + CDNS_I2C_CR_OFFSET); + + /* Setting slave address */ + cdns_i2c_writereg(id->slave->addr & CDNS_I2C_ADDR_MASK, + CDNS_I2C_ADDR_OFFSET); + + /* Enable slave send/receive interrupts */ + cdns_i2c_writereg(CDNS_I2C_IXR_SLAVE_INTR_MASK, + CDNS_I2C_IER_OFFSET); + break; + } +} + +static void cdns_i2c_slave_rcv_data(struct cdns_i2c *id) +{ + u8 bytes; + unsigned char data; + + /* Prepare backend for data reception */ + if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) { + id->slave_state = CDNS_I2C_SLAVE_STATE_RECV; + i2c_slave_event(id->slave, I2C_SLAVE_WRITE_REQUESTED, NULL); + } + + /* Fetch number of bytes to receive */ + bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); + + /* Read data and send to backend */ + while (bytes--) { + data = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); + i2c_slave_event(id->slave, I2C_SLAVE_WRITE_RECEIVED, &data); + } +} + +static void cdns_i2c_slave_send_data(struct cdns_i2c *id) +{ + u8 data; + + /* Prepare backend for data transmission */ + if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) { + id->slave_state = CDNS_I2C_SLAVE_STATE_SEND; + i2c_slave_event(id->slave, I2C_SLAVE_READ_REQUESTED, &data); + } else { + i2c_slave_event(id->slave, I2C_SLAVE_READ_PROCESSED, &data); + } + + /* Send data over bus */ + cdns_i2c_writereg(data, CDNS_I2C_DATA_OFFSET); +} + +/** + * cdns_i2c_slave_isr - Interrupt handler for the I2C device in slave role + * @ptr: Pointer to I2C device private data + * + * This function handles the data interrupt and transfer complete interrupt of + * the I2C device in slave role. + * + * Return: IRQ_HANDLED always + */ +static irqreturn_t cdns_i2c_slave_isr(void *ptr) +{ + struct cdns_i2c *id = ptr; + unsigned int isr_status, i2c_status; + + /* Fetch the interrupt status */ + isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); + + /* Ignore masked interrupts */ + isr_status &= ~cdns_i2c_readreg(CDNS_I2C_IMR_OFFSET); + + /* Fetch transfer mode (send/receive) */ + i2c_status = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET); + + /* Handle data send/receive */ + if (i2c_status & CDNS_I2C_SR_RXRW) { + /* Send data to master */ + if (isr_status & CDNS_I2C_IXR_DATA) + cdns_i2c_slave_send_data(id); + + if (isr_status & CDNS_I2C_IXR_COMP) { + id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; + i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); + } + } else { + /* Receive data from master */ + if (isr_status & CDNS_I2C_IXR_DATA) + cdns_i2c_slave_rcv_data(id); + + if (isr_status & CDNS_I2C_IXR_COMP) { + cdns_i2c_slave_rcv_data(id); + id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; + i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); + } + } + + /* Master indicated xfer stop or fifo underflow/overflow */ + if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_RX_OVF | + CDNS_I2C_IXR_RX_UNF | CDNS_I2C_IXR_TX_OVF)) { + id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; + i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL); + cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET); + } + + return IRQ_HANDLED; +} +#endif + +/** + * cdns_i2c_master_isr - Interrupt handler for the I2C device in master role + * @ptr: Pointer to I2C device private data + * + * This function handles the data interrupt, transfer complete interrupt and + * the error interrupts of the I2C device in master role. + * + * Return: IRQ_HANDLED always + */ +static irqreturn_t cdns_i2c_master_isr(void *ptr) +{ + unsigned int isr_status, avail_bytes; + unsigned int bytes_to_send; + bool updatetx; + struct cdns_i2c *id = ptr; + /* Signal completion only after everything is updated */ + int done_flag = 0; + irqreturn_t status = IRQ_NONE; + + isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); + id->err_status = 0; + + /* Handling nack and arbitration lost interrupt */ + if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) { + done_flag = 1; + status = IRQ_HANDLED; + } + + /* + * Check if transfer size register needs to be updated again for a + * large data receive operation. + */ + updatetx = id->recv_count > id->curr_recv_count; + + /* When receiving, handle data interrupt and completion interrupt */ + if (id->p_recv_buf && + ((isr_status & CDNS_I2C_IXR_COMP) || + (isr_status & CDNS_I2C_IXR_DATA))) { + /* Read data if receive data valid is set */ + while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & + CDNS_I2C_SR_RXDV) { + if (id->recv_count > 0) { + *(id->p_recv_buf)++ = + cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); + id->recv_count--; + id->curr_recv_count--; + + /* + * Clear hold bit that was set for FIFO control + * if RX data left is less than or equal to + * FIFO DEPTH unless repeated start is selected + */ + if (id->recv_count <= id->fifo_depth && + !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); + + } else { + dev_err(id->adap.dev.parent, + "xfer_size reg rollover. xfer aborted!\n"); + id->err_status |= CDNS_I2C_IXR_TO; + break; + } + + if (cdns_is_holdquirk(id, updatetx)) + break; + } + + /* + * The controller sends NACK to the slave when transfer size + * register reaches zero without considering the HOLD bit. + * This workaround is implemented for large data transfers to + * maintain transfer size non-zero while performing a large + * receive operation. + */ + if (cdns_is_holdquirk(id, updatetx)) { + /* wait while fifo is full */ + while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) != + (id->curr_recv_count - id->fifo_depth)) + ; + + /* + * Check number of bytes to be received against maximum + * transfer size and update register accordingly. + */ + if (((int)(id->recv_count) - id->fifo_depth) > + id->transfer_size) { + cdns_i2c_writereg(id->transfer_size, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = id->transfer_size + + id->fifo_depth; + } else { + cdns_i2c_writereg(id->recv_count - + id->fifo_depth, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = id->recv_count; + } + } + + /* Clear hold (if not repeated start) and signal completion */ + if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) { + if (!id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); + done_flag = 1; + } + + status = IRQ_HANDLED; + } + + /* When sending, handle transfer complete interrupt */ + if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) { + /* + * If there is more data to be sent, calculate the + * space available in FIFO and fill with that many bytes. + */ + if (id->send_count) { + avail_bytes = id->fifo_depth - + cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); + if (id->send_count > avail_bytes) + bytes_to_send = avail_bytes; + else + bytes_to_send = id->send_count; + + while (bytes_to_send--) { + cdns_i2c_writereg( + (*(id->p_send_buf)++), + CDNS_I2C_DATA_OFFSET); + id->send_count--; + } + } else { + /* + * Signal the completion of transaction and + * clear the hold bus bit if there are no + * further messages to be processed. + */ + done_flag = 1; + } + if (!id->send_count && !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); + + status = IRQ_HANDLED; + } + + /* Update the status for errors */ + id->err_status |= isr_status & CDNS_I2C_IXR_ERR_INTR_MASK; + if (id->err_status) + status = IRQ_HANDLED; + + if (done_flag) + complete(&id->xfer_done); + + return status; +} + +/** + * cdns_i2c_isr - Interrupt handler for the I2C device + * @irq: irq number for the I2C device + * @ptr: void pointer to cdns_i2c structure + * + * This function passes the control to slave/master based on current role of + * i2c controller. + * + * Return: IRQ_HANDLED always + */ +static irqreturn_t cdns_i2c_isr(int irq, void *ptr) +{ +#if IS_ENABLED(CONFIG_I2C_SLAVE) + struct cdns_i2c *id = ptr; + + if (id->dev_mode == CDNS_I2C_MODE_SLAVE) + return cdns_i2c_slave_isr(ptr); +#endif + return cdns_i2c_master_isr(ptr); +} + +/** + * cdns_i2c_mrecv - Prepare and start a master receive operation + * @id: pointer to the i2c device structure + */ +static void cdns_i2c_mrecv(struct cdns_i2c *id) +{ + unsigned int ctrl_reg; + unsigned int isr_status; + unsigned long flags; + bool hold_clear = false; + bool irq_save = false; + + u32 addr; + + id->p_recv_buf = id->p_msg->buf; + id->recv_count = id->p_msg->len; + + /* Put the controller in master receive mode and clear the FIFO */ + ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO; + + /* + * Receive up to I2C_SMBUS_BLOCK_MAX data bytes, plus one message length + * byte, plus one checksum byte if PEC is enabled. p_msg->len will be 2 if + * PEC is enabled, otherwise 1. + */ + if (id->p_msg->flags & I2C_M_RECV_LEN) + id->recv_count = I2C_SMBUS_BLOCK_MAX + id->p_msg->len; + + id->curr_recv_count = id->recv_count; + + /* + * Check for the message size against FIFO depth and set the + * 'hold bus' bit if it is greater than FIFO depth. + */ + if (id->recv_count > id->fifo_depth) + ctrl_reg |= CDNS_I2C_CR_HOLD; + + cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); + + /* Clear the interrupts in interrupt status register */ + isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); + + /* + * The no. of bytes to receive is checked against the limit of + * max transfer size. Set transfer size register with no of bytes + * receive if it is less than transfer size and transfer size if + * it is more. Enable the interrupts. + */ + if (id->recv_count > id->transfer_size) { + cdns_i2c_writereg(id->transfer_size, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = id->transfer_size; + } else { + cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET); + } + + /* Determine hold_clear based on number of bytes to receive and hold flag */ + if (!id->bus_hold_flag && id->recv_count <= id->fifo_depth) { + if (ctrl_reg & CDNS_I2C_CR_HOLD) { + hold_clear = true; + if (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) + irq_save = true; + } + } + + addr = id->p_msg->addr; + addr &= CDNS_I2C_ADDR_MASK; + + if (hold_clear) { + ctrl_reg &= ~CDNS_I2C_CR_HOLD; + /* + * In case of Xilinx Zynq SOC, clear the HOLD bit before transfer size + * register reaches '0'. This is an IP bug which causes transfer size + * register overflow to 0xFF. To satisfy this timing requirement, + * disable the interrupts on current processor core between register + * writes to slave address register and control register. + */ + if (irq_save) + local_irq_save(flags); + + cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); + cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); + /* Read it back to avoid bufferring and make sure write happens */ + cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + + if (irq_save) + local_irq_restore(flags); + } else { + cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); + } + + cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); +} + +/** + * cdns_i2c_msend - Prepare and start a master send operation + * @id: pointer to the i2c device + */ +static void cdns_i2c_msend(struct cdns_i2c *id) +{ + unsigned int avail_bytes; + unsigned int bytes_to_send; + unsigned int ctrl_reg; + unsigned int isr_status; + + id->p_recv_buf = NULL; + id->p_send_buf = id->p_msg->buf; + id->send_count = id->p_msg->len; + + /* Set the controller in Master transmit mode and clear the FIFO. */ + ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + ctrl_reg &= ~CDNS_I2C_CR_RW; + ctrl_reg |= CDNS_I2C_CR_CLR_FIFO; + + /* + * Check for the message size against FIFO depth and set the + * 'hold bus' bit if it is greater than FIFO depth. + */ + if (id->send_count > id->fifo_depth) + ctrl_reg |= CDNS_I2C_CR_HOLD; + cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); + + /* Clear the interrupts in interrupt status register. */ + isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET); + + /* + * Calculate the space available in FIFO. Check the message length + * against the space available, and fill the FIFO accordingly. + * Enable the interrupts. + */ + avail_bytes = id->fifo_depth - + cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); + + if (id->send_count > avail_bytes) + bytes_to_send = avail_bytes; + else + bytes_to_send = id->send_count; + + while (bytes_to_send--) { + cdns_i2c_writereg((*(id->p_send_buf)++), CDNS_I2C_DATA_OFFSET); + id->send_count--; + } + + /* + * Clear the bus hold flag if there is no more data + * and if it is the last message. + */ + if (!id->bus_hold_flag && !id->send_count) + cdns_i2c_clear_bus_hold(id); + /* Set the slave address in address register - triggers operation. */ + cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK, + CDNS_I2C_ADDR_OFFSET); + + cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); +} + +/** + * cdns_i2c_master_reset - Reset the interface + * @adap: pointer to the i2c adapter driver instance + * + * This function cleanup the fifos, clear the hold bit and status + * and disable the interrupts. + */ +static void cdns_i2c_master_reset(struct i2c_adapter *adap) +{ + struct cdns_i2c *id = adap->algo_data; + u32 regval; + + /* Disable the interrupts */ + cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET); + /* Clear the hold bit and fifos */ + regval = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + regval &= ~CDNS_I2C_CR_HOLD; + regval |= CDNS_I2C_CR_CLR_FIFO; + cdns_i2c_writereg(regval, CDNS_I2C_CR_OFFSET); + /* Update the transfercount register to zero */ + cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET); + /* Clear the interrupt status register */ + regval = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(regval, CDNS_I2C_ISR_OFFSET); + /* Clear the status register */ + regval = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET); + cdns_i2c_writereg(regval, CDNS_I2C_SR_OFFSET); +} + +static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg, + struct i2c_adapter *adap) +{ + unsigned long time_left, msg_timeout; + u32 reg; + + id->p_msg = msg; + id->err_status = 0; + reinit_completion(&id->xfer_done); + + /* Check for the TEN Bit mode on each msg */ + reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + if (msg->flags & I2C_M_TEN) { + if (reg & CDNS_I2C_CR_NEA) + cdns_i2c_writereg(reg & ~CDNS_I2C_CR_NEA, + CDNS_I2C_CR_OFFSET); + } else { + if (!(reg & CDNS_I2C_CR_NEA)) + cdns_i2c_writereg(reg | CDNS_I2C_CR_NEA, + CDNS_I2C_CR_OFFSET); + } + + /* Check for the R/W flag on each msg */ + if (msg->flags & I2C_M_RD) + cdns_i2c_mrecv(id); + else + cdns_i2c_msend(id); + + /* Minimal time to execute this message */ + msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk); + /* Plus some wiggle room */ + msg_timeout += msecs_to_jiffies(500); + + if (msg_timeout < adap->timeout) + msg_timeout = adap->timeout; + + /* Wait for the signal of completion */ + time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout); + if (time_left == 0) { + cdns_i2c_master_reset(adap); + dev_err(id->adap.dev.parent, + "timeout waiting on completion\n"); + return -ETIMEDOUT; + } + + cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, + CDNS_I2C_IDR_OFFSET); + + /* If it is bus arbitration error, try again */ + if (id->err_status & CDNS_I2C_IXR_ARB_LOST) + return -EAGAIN; + + if (msg->flags & I2C_M_RECV_LEN) + msg->len += min_t(unsigned int, msg->buf[0], I2C_SMBUS_BLOCK_MAX); + + return 0; +} + +/** + * cdns_i2c_master_xfer - The main i2c transfer function + * @adap: pointer to the i2c adapter driver instance + * @msgs: pointer to the i2c message structure + * @num: the number of messages to transfer + * + * Initiates the send/recv activity based on the transfer message received. + * + * Return: number of msgs processed on success, negative error otherwise + */ +static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + int ret, count; + u32 reg; + struct cdns_i2c *id = adap->algo_data; + bool hold_quirk; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + bool change_role = false; +#endif + + ret = pm_runtime_resume_and_get(id->dev); + if (ret < 0) + return ret; + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + /* Check i2c operating mode and switch if possible */ + if (id->dev_mode == CDNS_I2C_MODE_SLAVE) { + if (id->slave_state != CDNS_I2C_SLAVE_STATE_IDLE) { + ret = -EAGAIN; + goto out; + } + + /* Set mode to master */ + cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id); + + /* Mark flag to change role once xfer is completed */ + change_role = true; + } +#endif + + /* Check if the bus is free */ + + ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET, + reg, + !(reg & CDNS_I2C_SR_BA), + CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US); + if (ret) { + ret = -EAGAIN; + if (id->adap.bus_recovery_info) + i2c_recover_bus(adap); + goto out; + } + + hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT); + /* + * Set the flag to one when multiple messages are to be + * processed with a repeated start. + */ + if (num > 1) { + /* + * This controller does not give completion interrupt after a + * master receive message if HOLD bit is set (repeated start), + * resulting in SW timeout. Hence, if a receive message is + * followed by any other message, an error is returned + * indicating that this sequence is not supported. + */ + for (count = 0; (count < num - 1 && hold_quirk); count++) { + if (msgs[count].flags & I2C_M_RD) { + dev_warn(adap->dev.parent, + "Can't do repeated start after a receive message\n"); + ret = -EOPNOTSUPP; + goto out; + } + } + id->bus_hold_flag = 1; + reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); + reg |= CDNS_I2C_CR_HOLD; + cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET); + } else { + id->bus_hold_flag = 0; + } + + /* Process the msg one by one */ + for (count = 0; count < num; count++, msgs++) { + if (count == (num - 1)) + id->bus_hold_flag = 0; + + ret = cdns_i2c_process_msg(id, msgs, adap); + if (ret) + goto out; + + /* Report the other error interrupts to application */ + if (id->err_status) { + cdns_i2c_master_reset(adap); + + if (id->err_status & CDNS_I2C_IXR_NACK) { + ret = -ENXIO; + goto out; + } + ret = -EIO; + goto out; + } + } + + ret = num; + +out: + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + /* Switch i2c mode to slave */ + if (change_role) + cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id); +#endif + + pm_runtime_mark_last_busy(id->dev); + pm_runtime_put_autosuspend(id->dev); + return ret; +} + +/** + * cdns_i2c_func - Returns the supported features of the I2C driver + * @adap: pointer to the i2c adapter structure + * + * Return: 32 bit value, each bit corresponding to a feature + */ +static u32 cdns_i2c_func(struct i2c_adapter *adap) +{ + u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | + (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | + I2C_FUNC_SMBUS_BLOCK_DATA; + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + func |= I2C_FUNC_SLAVE; +#endif + + return func; +} + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static int cdns_reg_slave(struct i2c_client *slave) +{ + int ret; + struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c, + adap); + + if (id->slave) + return -EBUSY; + + if (slave->flags & I2C_CLIENT_TEN) + return -EAFNOSUPPORT; + + ret = pm_runtime_resume_and_get(id->dev); + if (ret < 0) + return ret; + + /* Store slave information */ + id->slave = slave; + + /* Enable I2C slave */ + cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id); + + return 0; +} + +static int cdns_unreg_slave(struct i2c_client *slave) +{ + struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c, + adap); + + pm_runtime_put(id->dev); + + /* Remove slave information */ + id->slave = NULL; + + /* Enable I2C master */ + cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id); + + return 0; +} +#endif + +static const struct i2c_algorithm cdns_i2c_algo = { + .master_xfer = cdns_i2c_master_xfer, + .functionality = cdns_i2c_func, +#if IS_ENABLED(CONFIG_I2C_SLAVE) + .reg_slave = cdns_reg_slave, + .unreg_slave = cdns_unreg_slave, +#endif +}; + +/** + * cdns_i2c_calc_divs - Calculate clock dividers + * @f: I2C clock frequency + * @input_clk: Input clock frequency + * @a: First divider (return value) + * @b: Second divider (return value) + * + * f is used as input and output variable. As input it is used as target I2C + * frequency. On function exit f holds the actually resulting I2C frequency. + * + * Return: 0 on success, negative errno otherwise. + */ +static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk, + unsigned int *a, unsigned int *b) +{ + unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp; + unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0; + unsigned int last_error, current_error; + + /* calculate (divisor_a+1) x (divisor_b+1) */ + temp = input_clk / (22 * fscl); + + /* + * If the calculated value is negative or 0, the fscl input is out of + * range. Return error. + */ + if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX))) + return -EINVAL; + + last_error = -1; + for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) { + div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1)); + + if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX)) + continue; + div_b--; + + actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1)); + + if (actual_fscl > fscl) + continue; + + current_error = fscl - actual_fscl; + + if (last_error > current_error) { + calc_div_a = div_a; + calc_div_b = div_b; + best_fscl = actual_fscl; + last_error = current_error; + } + } + + *a = calc_div_a; + *b = calc_div_b; + *f = best_fscl; + + return 0; +} + +/** + * cdns_i2c_setclk - This function sets the serial clock rate for the I2C device + * @clk_in: I2C clock input frequency in Hz + * @id: Pointer to the I2C device structure + * + * The device must be idle rather than busy transferring data before setting + * these device options. + * The data rate is set by values in the control register. + * The formula for determining the correct register values is + * Fscl = Fpclk/(22 x (divisor_a+1) x (divisor_b+1)) + * See the hardware data sheet for a full explanation of setting the serial + * clock rate. The clock can not be faster than the input clock divide by 22. + * The two most common clock rates are 100KHz and 400KHz. + * + * Return: 0 on success, negative error otherwise + */ +static int cdns_i2c_setclk(unsigned long clk_in, struct cdns_i2c *id) +{ + unsigned int div_a, div_b; + unsigned int ctrl_reg; + int ret = 0; + unsigned long fscl = id->i2c_clk; + + ret = cdns_i2c_calc_divs(&fscl, clk_in, &div_a, &div_b); + if (ret) + return ret; + + ctrl_reg = id->ctrl_reg; + ctrl_reg &= ~(CDNS_I2C_CR_DIVA_MASK | CDNS_I2C_CR_DIVB_MASK); + ctrl_reg |= ((div_a << CDNS_I2C_CR_DIVA_SHIFT) | + (div_b << CDNS_I2C_CR_DIVB_SHIFT)); + id->ctrl_reg = ctrl_reg; + cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); +#if IS_ENABLED(CONFIG_I2C_SLAVE) + id->ctrl_reg_diva_divb = ctrl_reg & (CDNS_I2C_CR_DIVA_MASK | + CDNS_I2C_CR_DIVB_MASK); +#endif + return 0; +} + +/** + * cdns_i2c_clk_notifier_cb - Clock rate change callback + * @nb: Pointer to notifier block + * @event: Notification reason + * @data: Pointer to notification data object + * + * This function is called when the cdns_i2c input clock frequency changes. + * The callback checks whether a valid bus frequency can be generated after the + * change. If so, the change is acknowledged, otherwise the change is aborted. + * New dividers are written to the HW in the pre- or post change notification + * depending on the scaling direction. + * + * Return: NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK + * to acknowledge the change, NOTIFY_DONE if the notification is + * considered irrelevant. + */ +static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long + event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct cdns_i2c *id = to_cdns_i2c(nb); + + if (pm_runtime_suspended(id->dev)) + return NOTIFY_OK; + + switch (event) { + case PRE_RATE_CHANGE: + { + unsigned long input_clk = ndata->new_rate; + unsigned long fscl = id->i2c_clk; + unsigned int div_a, div_b; + int ret; + + ret = cdns_i2c_calc_divs(&fscl, input_clk, &div_a, &div_b); + if (ret) { + dev_warn(id->adap.dev.parent, + "clock rate change rejected\n"); + return NOTIFY_STOP; + } + + /* scale up */ + if (ndata->new_rate > ndata->old_rate) + cdns_i2c_setclk(ndata->new_rate, id); + + return NOTIFY_OK; + } + case POST_RATE_CHANGE: + id->input_clk = ndata->new_rate; + /* scale down */ + if (ndata->new_rate < ndata->old_rate) + cdns_i2c_setclk(ndata->new_rate, id); + return NOTIFY_OK; + case ABORT_RATE_CHANGE: + /* scale up */ + if (ndata->new_rate > ndata->old_rate) + cdns_i2c_setclk(ndata->old_rate, id); + return NOTIFY_OK; + default: + return NOTIFY_DONE; + } +} + +/** + * cdns_i2c_runtime_suspend - Runtime suspend method for the driver + * @dev: Address of the platform_device structure + * + * Put the driver into low power mode. + * + * Return: 0 always + */ +static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev) +{ + struct cdns_i2c *xi2c = dev_get_drvdata(dev); + + clk_disable(xi2c->clk); + + return 0; +} + +/** + * cdns_i2c_init - Controller initialisation + * @id: Device private data structure + * + * Initialise the i2c controller. + * + */ +static void cdns_i2c_init(struct cdns_i2c *id) +{ + cdns_i2c_writereg(id->ctrl_reg, CDNS_I2C_CR_OFFSET); + /* + * Cadence I2C controller has a bug wherein it generates + * invalid read transaction after HW timeout in master receiver mode. + * HW timeout is not used by this driver and the interrupt is disabled. + * But the feature itself cannot be disabled. Hence maximum value + * is written to this register to reduce the chances of error. + */ + cdns_i2c_writereg(CDNS_I2C_TIMEOUT_MAX, CDNS_I2C_TIME_OUT_OFFSET); +} + +/** + * cdns_i2c_runtime_resume - Runtime resume + * @dev: Address of the platform_device structure + * + * Runtime resume callback. + * + * Return: 0 on success and error value on error + */ +static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev) +{ + struct cdns_i2c *xi2c = dev_get_drvdata(dev); + int ret; + + ret = clk_enable(xi2c->clk); + if (ret) { + dev_err(dev, "Cannot enable clock.\n"); + return ret; + } + cdns_i2c_init(xi2c); + + return 0; +} + +static const struct dev_pm_ops cdns_i2c_dev_pm_ops = { + SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend, + cdns_i2c_runtime_resume, NULL) +}; + +static const struct cdns_platform_data r1p10_i2c_def = { + .quirks = CDNS_I2C_BROKEN_HOLD_BIT, +}; + +static const struct of_device_id cdns_i2c_of_match[] = { + { .compatible = "cdns,i2c-r1p10", .data = &r1p10_i2c_def }, + { .compatible = "cdns,i2c-r1p14",}, + { /* end of table */ } +}; +MODULE_DEVICE_TABLE(of, cdns_i2c_of_match); + +/** + * cdns_i2c_detect_transfer_size - Detect the maximum transfer size supported + * @id: Device private data structure + * + * Detect the maximum transfer size that is supported by this instance of the + * Cadence I2C controller. + */ +static void cdns_i2c_detect_transfer_size(struct cdns_i2c *id) +{ + u32 val; + + /* + * Writing to the transfer size register is only possible if these two bits + * are set in the control register. + */ + cdns_i2c_writereg(CDNS_I2C_CR_MS | CDNS_I2C_CR_RW, CDNS_I2C_CR_OFFSET); + + /* + * The number of writable bits of the transfer size register can be between + * 4 and 8. This is a controlled through a synthesis parameter of the IP + * core and can vary from instance to instance. The unused MSBs always read + * back as 0. Writing 0xff and then reading the value back will report the + * maximum supported transfer size. + */ + cdns_i2c_writereg(CDNS_I2C_MAX_TRANSFER_SIZE, CDNS_I2C_XFER_SIZE_OFFSET); + val = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); + id->transfer_size = CDNS_I2C_TRANSFER_SIZE(val); + cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET); + cdns_i2c_writereg(0, CDNS_I2C_CR_OFFSET); +} + +/** + * cdns_i2c_probe - Platform registration call + * @pdev: Handle to the platform device structure + * + * This function does all the memory allocation and registration for the i2c + * device. User can modify the address mode to 10 bit address mode using the + * ioctl call with option I2C_TENBIT. + * + * Return: 0 on success, negative error otherwise + */ +static int cdns_i2c_probe(struct platform_device *pdev) +{ + struct resource *r_mem; + struct cdns_i2c *id; + int ret, irq; + const struct of_device_id *match; + + id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL); + if (!id) + return -ENOMEM; + + id->dev = &pdev->dev; + platform_set_drvdata(pdev, id); + + match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node); + if (match && match->data) { + const struct cdns_platform_data *data = match->data; + id->quirks = data->quirks; + } + + id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev); + if (IS_ERR(id->rinfo.pinctrl)) { + int err = PTR_ERR(id->rinfo.pinctrl); + + dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n"); + if (err != -ENODEV) + return err; + } else { + id->adap.bus_recovery_info = &id->rinfo; + } + + id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem); + if (IS_ERR(id->membase)) + return PTR_ERR(id->membase); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + id->adap.owner = THIS_MODULE; + id->adap.dev.of_node = pdev->dev.of_node; + id->adap.algo = &cdns_i2c_algo; + id->adap.timeout = CDNS_I2C_TIMEOUT; + id->adap.retries = 3; /* Default retry value. */ + id->adap.algo_data = id; + id->adap.dev.parent = &pdev->dev; + init_completion(&id->xfer_done); + snprintf(id->adap.name, sizeof(id->adap.name), + "Cadence I2C at %08lx", (unsigned long)r_mem->start); + + id->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(id->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(id->clk), + "input clock not found.\n"); + + id->reset = devm_reset_control_get_optional_shared(&pdev->dev, NULL); + if (IS_ERR(id->reset)) + return dev_err_probe(&pdev->dev, PTR_ERR(id->reset), + "Failed to request reset.\n"); + + ret = clk_prepare_enable(id->clk); + if (ret) + dev_err(&pdev->dev, "Unable to enable clock.\n"); + + ret = reset_control_deassert(id->reset); + if (ret) { + dev_err_probe(&pdev->dev, ret, + "Failed to de-assert reset.\n"); + goto err_clk_dis; + } + + pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT); + pm_runtime_use_autosuspend(id->dev); + pm_runtime_set_active(id->dev); + pm_runtime_enable(id->dev); + + id->clk_rate_change_nb.notifier_call = cdns_i2c_clk_notifier_cb; + if (clk_notifier_register(id->clk, &id->clk_rate_change_nb)) + dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); + id->input_clk = clk_get_rate(id->clk); + + ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &id->i2c_clk); + if (ret || (id->i2c_clk > I2C_MAX_FAST_MODE_FREQ)) + id->i2c_clk = I2C_MAX_STANDARD_MODE_FREQ; + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + /* Set initial mode to master */ + id->dev_mode = CDNS_I2C_MODE_MASTER; + id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE; +#endif + id->ctrl_reg = CDNS_I2C_CR_ACK_EN | CDNS_I2C_CR_NEA | CDNS_I2C_CR_MS; + + id->fifo_depth = CDNS_I2C_FIFO_DEPTH_DEFAULT; + of_property_read_u32(pdev->dev.of_node, "fifo-depth", &id->fifo_depth); + + cdns_i2c_detect_transfer_size(id); + + ret = cdns_i2c_setclk(id->input_clk, id); + if (ret) { + dev_err(&pdev->dev, "invalid SCL clock: %u Hz\n", id->i2c_clk); + ret = -EINVAL; + goto err_clk_notifier_unregister; + } + + ret = devm_request_irq(&pdev->dev, irq, cdns_i2c_isr, 0, + DRIVER_NAME, id); + if (ret) { + dev_err(&pdev->dev, "cannot get irq %d\n", irq); + goto err_clk_notifier_unregister; + } + cdns_i2c_init(id); + + ret = i2c_add_adapter(&id->adap); + if (ret < 0) + goto err_clk_notifier_unregister; + + dev_info(&pdev->dev, "%u kHz mmio %08lx irq %d\n", + id->i2c_clk / 1000, (unsigned long)r_mem->start, irq); + + return 0; + +err_clk_notifier_unregister: + clk_notifier_unregister(id->clk, &id->clk_rate_change_nb); + reset_control_assert(id->reset); +err_clk_dis: + clk_disable_unprepare(id->clk); + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + return ret; +} + +/** + * cdns_i2c_remove - Unregister the device after releasing the resources + * @pdev: Handle to the platform device structure + * + * This function frees all the resources allocated to the device. + * + * Return: 0 always + */ +static void cdns_i2c_remove(struct platform_device *pdev) +{ + struct cdns_i2c *id = platform_get_drvdata(pdev); + + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_dont_use_autosuspend(&pdev->dev); + + i2c_del_adapter(&id->adap); + clk_notifier_unregister(id->clk, &id->clk_rate_change_nb); + reset_control_assert(id->reset); + clk_disable_unprepare(id->clk); +} + +static struct platform_driver cdns_i2c_drv = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = cdns_i2c_of_match, + .pm = &cdns_i2c_dev_pm_ops, + }, + .probe = cdns_i2c_probe, + .remove_new = cdns_i2c_remove, +}; + +module_platform_driver(cdns_i2c_drv); + +MODULE_AUTHOR("Xilinx Inc."); +MODULE_DESCRIPTION("Cadence I2C bus driver"); +MODULE_LICENSE("GPL"); |