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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/i2c/busses/i2c-axxia.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/i2c/busses/i2c-axxia.c')
-rw-r--r--drivers/i2c/busses/i2c-axxia.c838
1 files changed, 838 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
new file mode 100644
index 000000000..bdf3b50de
--- /dev/null
+++ b/drivers/i2c/busses/i2c-axxia.c
@@ -0,0 +1,838 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This driver implements I2C master functionality using the LSI API2C
+ * controller.
+ *
+ * NOTE: The controller has a limitation in that it can only do transfers of
+ * maximum 255 bytes at a time. If a larger transfer is attempted, error code
+ * (-EINVAL) is returned.
+ */
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#define SCL_WAIT_TIMEOUT_NS 25000000
+#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
+#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
+#define FIFO_SIZE 8
+#define SEQ_LEN 2
+
+#define GLOBAL_CONTROL 0x00
+#define GLOBAL_MST_EN BIT(0)
+#define GLOBAL_SLV_EN BIT(1)
+#define GLOBAL_IBML_EN BIT(2)
+#define INTERRUPT_STATUS 0x04
+#define INTERRUPT_ENABLE 0x08
+#define INT_SLV BIT(1)
+#define INT_MST BIT(0)
+#define WAIT_TIMER_CONTROL 0x0c
+#define WT_EN BIT(15)
+#define WT_VALUE(_x) ((_x) & 0x7fff)
+#define IBML_TIMEOUT 0x10
+#define IBML_LOW_MEXT 0x14
+#define IBML_LOW_SEXT 0x18
+#define TIMER_CLOCK_DIV 0x1c
+#define I2C_BUS_MONITOR 0x20
+#define BM_SDAC BIT(3)
+#define BM_SCLC BIT(2)
+#define BM_SDAS BIT(1)
+#define BM_SCLS BIT(0)
+#define SOFT_RESET 0x24
+#define MST_COMMAND 0x28
+#define CMD_BUSY (1<<3)
+#define CMD_MANUAL (0x00 | CMD_BUSY)
+#define CMD_AUTO (0x01 | CMD_BUSY)
+#define CMD_SEQUENCE (0x02 | CMD_BUSY)
+#define MST_RX_XFER 0x2c
+#define MST_TX_XFER 0x30
+#define MST_ADDR_1 0x34
+#define MST_ADDR_2 0x38
+#define MST_DATA 0x3c
+#define MST_TX_FIFO 0x40
+#define MST_RX_FIFO 0x44
+#define MST_INT_ENABLE 0x48
+#define MST_INT_STATUS 0x4c
+#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */
+#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */
+#define MST_STATUS_SNS (1 << 11) /* Manual mode done */
+#define MST_STATUS_SS (1 << 10) /* Automatic mode done */
+#define MST_STATUS_SCC (1 << 9) /* Stop complete */
+#define MST_STATUS_IP (1 << 8) /* Invalid parameter */
+#define MST_STATUS_TSS (1 << 7) /* Timeout */
+#define MST_STATUS_AL (1 << 6) /* Arbitration lost */
+#define MST_STATUS_ND (1 << 5) /* NAK on data phase */
+#define MST_STATUS_NA (1 << 4) /* NAK on address phase */
+#define MST_STATUS_NAK (MST_STATUS_NA | \
+ MST_STATUS_ND)
+#define MST_STATUS_ERR (MST_STATUS_NAK | \
+ MST_STATUS_AL | \
+ MST_STATUS_IP)
+#define MST_TX_BYTES_XFRD 0x50
+#define MST_RX_BYTES_XFRD 0x54
+#define SLV_ADDR_DEC_CTL 0x58
+#define SLV_ADDR_DEC_GCE BIT(0) /* ACK to General Call Address from own master (loopback) */
+#define SLV_ADDR_DEC_OGCE BIT(1) /* ACK to General Call Address from external masters */
+#define SLV_ADDR_DEC_SA1E BIT(2) /* ACK to addr_1 enabled */
+#define SLV_ADDR_DEC_SA1M BIT(3) /* 10-bit addressing for addr_1 enabled */
+#define SLV_ADDR_DEC_SA2E BIT(4) /* ACK to addr_2 enabled */
+#define SLV_ADDR_DEC_SA2M BIT(5) /* 10-bit addressing for addr_2 enabled */
+#define SLV_ADDR_1 0x5c
+#define SLV_ADDR_2 0x60
+#define SLV_RX_CTL 0x64
+#define SLV_RX_ACSA1 BIT(0) /* Generate ACK for writes to addr_1 */
+#define SLV_RX_ACSA2 BIT(1) /* Generate ACK for writes to addr_2 */
+#define SLV_RX_ACGCA BIT(2) /* ACK data phase transfers to General Call Address */
+#define SLV_DATA 0x68
+#define SLV_RX_FIFO 0x6c
+#define SLV_FIFO_DV1 BIT(0) /* Data Valid for addr_1 */
+#define SLV_FIFO_DV2 BIT(1) /* Data Valid for addr_2 */
+#define SLV_FIFO_AS BIT(2) /* (N)ACK Sent */
+#define SLV_FIFO_TNAK BIT(3) /* Timeout NACK */
+#define SLV_FIFO_STRC BIT(4) /* First byte after start condition received */
+#define SLV_FIFO_RSC BIT(5) /* Repeated Start Condition */
+#define SLV_FIFO_STPC BIT(6) /* Stop Condition */
+#define SLV_FIFO_DV (SLV_FIFO_DV1 | SLV_FIFO_DV2)
+#define SLV_INT_ENABLE 0x70
+#define SLV_INT_STATUS 0x74
+#define SLV_STATUS_RFH BIT(0) /* FIFO service */
+#define SLV_STATUS_WTC BIT(1) /* Write transfer complete */
+#define SLV_STATUS_SRS1 BIT(2) /* Slave read from addr 1 */
+#define SLV_STATUS_SRRS1 BIT(3) /* Repeated start from addr 1 */
+#define SLV_STATUS_SRND1 BIT(4) /* Read request not following start condition */
+#define SLV_STATUS_SRC1 BIT(5) /* Read canceled */
+#define SLV_STATUS_SRAT1 BIT(6) /* Slave Read timed out */
+#define SLV_STATUS_SRDRE1 BIT(7) /* Data written after timed out */
+#define SLV_READ_DUMMY 0x78
+#define SCL_HIGH_PERIOD 0x80
+#define SCL_LOW_PERIOD 0x84
+#define SPIKE_FLTR_LEN 0x88
+#define SDA_SETUP_TIME 0x8c
+#define SDA_HOLD_TIME 0x90
+
+/**
+ * axxia_i2c_dev - I2C device context
+ * @base: pointer to register struct
+ * @msg: pointer to current message
+ * @msg_r: pointer to current read message (sequence transfer)
+ * @msg_xfrd: number of bytes transferred in tx_fifo
+ * @msg_xfrd_r: number of bytes transferred in rx_fifo
+ * @msg_err: error code for completed message
+ * @msg_complete: xfer completion object
+ * @dev: device reference
+ * @adapter: core i2c abstraction
+ * @i2c_clk: clock reference for i2c input clock
+ * @bus_clk_rate: current i2c bus clock rate
+ * @last: a flag indicating is this is last message in transfer
+ */
+struct axxia_i2c_dev {
+ void __iomem *base;
+ struct i2c_msg *msg;
+ struct i2c_msg *msg_r;
+ size_t msg_xfrd;
+ size_t msg_xfrd_r;
+ int msg_err;
+ struct completion msg_complete;
+ struct device *dev;
+ struct i2c_adapter adapter;
+ struct clk *i2c_clk;
+ u32 bus_clk_rate;
+ bool last;
+ struct i2c_client *slave;
+ int irq;
+};
+
+static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
+{
+ u32 int_en;
+
+ int_en = readl(idev->base + MST_INT_ENABLE);
+ writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
+}
+
+static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
+{
+ u32 int_en;
+
+ int_en = readl(idev->base + MST_INT_ENABLE);
+ writel(int_en | mask, idev->base + MST_INT_ENABLE);
+}
+
+/**
+ * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
+ */
+static u32 ns_to_clk(u64 ns, u32 clk_mhz)
+{
+ return div_u64(ns * clk_mhz, 1000);
+}
+
+static int axxia_i2c_init(struct axxia_i2c_dev *idev)
+{
+ u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
+ u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
+ u32 t_setup;
+ u32 t_high, t_low;
+ u32 tmo_clk;
+ u32 prescale;
+ unsigned long timeout;
+
+ dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
+ idev->bus_clk_rate, clk_mhz, divisor);
+
+ /* Reset controller */
+ writel(0x01, idev->base + SOFT_RESET);
+ timeout = jiffies + msecs_to_jiffies(100);
+ while (readl(idev->base + SOFT_RESET) & 1) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(idev->dev, "Soft reset failed\n");
+ break;
+ }
+ }
+
+ /* Enable Master Mode */
+ writel(0x1, idev->base + GLOBAL_CONTROL);
+
+ if (idev->bus_clk_rate <= I2C_MAX_STANDARD_MODE_FREQ) {
+ /* Standard mode SCL 50/50, tSU:DAT = 250 ns */
+ t_high = divisor * 1 / 2;
+ t_low = divisor * 1 / 2;
+ t_setup = ns_to_clk(250, clk_mhz);
+ } else {
+ /* Fast mode SCL 33/66, tSU:DAT = 100 ns */
+ t_high = divisor * 1 / 3;
+ t_low = divisor * 2 / 3;
+ t_setup = ns_to_clk(100, clk_mhz);
+ }
+
+ /* SCL High Time */
+ writel(t_high, idev->base + SCL_HIGH_PERIOD);
+ /* SCL Low Time */
+ writel(t_low, idev->base + SCL_LOW_PERIOD);
+ /* SDA Setup Time */
+ writel(t_setup, idev->base + SDA_SETUP_TIME);
+ /* SDA Hold Time, 300ns */
+ writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
+ /* Filter <50ns spikes */
+ writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
+
+ /* Configure Time-Out Registers */
+ tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
+
+ /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
+ for (prescale = 0; prescale < 15; ++prescale) {
+ if (tmo_clk <= 0x7fff)
+ break;
+ tmo_clk >>= 1;
+ }
+ if (tmo_clk > 0x7fff)
+ tmo_clk = 0x7fff;
+
+ /* Prescale divider (log2) */
+ writel(prescale, idev->base + TIMER_CLOCK_DIV);
+ /* Timeout in divided clocks */
+ writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
+
+ /* Mask all master interrupt bits */
+ i2c_int_disable(idev, ~0);
+
+ /* Interrupt enable */
+ writel(0x01, idev->base + INTERRUPT_ENABLE);
+
+ return 0;
+}
+
+static int i2c_m_rd(const struct i2c_msg *msg)
+{
+ return (msg->flags & I2C_M_RD) != 0;
+}
+
+static int i2c_m_ten(const struct i2c_msg *msg)
+{
+ return (msg->flags & I2C_M_TEN) != 0;
+}
+
+static int i2c_m_recv_len(const struct i2c_msg *msg)
+{
+ return (msg->flags & I2C_M_RECV_LEN) != 0;
+}
+
+/**
+ * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
+ * transfer length if this is the first byte of such a transfer.
+ */
+static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
+{
+ struct i2c_msg *msg = idev->msg_r;
+ size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
+ int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd_r);
+
+ while (bytes_to_transfer-- > 0) {
+ int c = readl(idev->base + MST_DATA);
+
+ if (idev->msg_xfrd_r == 0 && i2c_m_recv_len(msg)) {
+ /*
+ * Check length byte for SMBus block read
+ */
+ if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
+ idev->msg_err = -EPROTO;
+ i2c_int_disable(idev, ~MST_STATUS_TSS);
+ complete(&idev->msg_complete);
+ break;
+ }
+ msg->len = 1 + c;
+ writel(msg->len, idev->base + MST_RX_XFER);
+ }
+ msg->buf[idev->msg_xfrd_r++] = c;
+ }
+
+ return 0;
+}
+
+/**
+ * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
+ * @return: Number of bytes left to transfer.
+ */
+static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
+{
+ struct i2c_msg *msg = idev->msg;
+ size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
+ int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
+ int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
+
+ while (bytes_to_transfer-- > 0)
+ writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
+
+ return ret;
+}
+
+static void axxia_i2c_slv_fifo_event(struct axxia_i2c_dev *idev)
+{
+ u32 fifo_status = readl(idev->base + SLV_RX_FIFO);
+ u8 val;
+
+ dev_dbg(idev->dev, "slave irq fifo_status=0x%x\n", fifo_status);
+
+ if (fifo_status & SLV_FIFO_DV1) {
+ if (fifo_status & SLV_FIFO_STRC)
+ i2c_slave_event(idev->slave,
+ I2C_SLAVE_WRITE_REQUESTED, &val);
+
+ val = readl(idev->base + SLV_DATA);
+ i2c_slave_event(idev->slave, I2C_SLAVE_WRITE_RECEIVED, &val);
+ }
+ if (fifo_status & SLV_FIFO_STPC) {
+ readl(idev->base + SLV_DATA); /* dummy read */
+ i2c_slave_event(idev->slave, I2C_SLAVE_STOP, &val);
+ }
+ if (fifo_status & SLV_FIFO_RSC)
+ readl(idev->base + SLV_DATA); /* dummy read */
+}
+
+static irqreturn_t axxia_i2c_slv_isr(struct axxia_i2c_dev *idev)
+{
+ u32 status = readl(idev->base + SLV_INT_STATUS);
+ u8 val;
+
+ dev_dbg(idev->dev, "slave irq status=0x%x\n", status);
+
+ if (status & SLV_STATUS_RFH)
+ axxia_i2c_slv_fifo_event(idev);
+ if (status & SLV_STATUS_SRS1) {
+ i2c_slave_event(idev->slave, I2C_SLAVE_READ_REQUESTED, &val);
+ writel(val, idev->base + SLV_DATA);
+ }
+ if (status & SLV_STATUS_SRND1) {
+ i2c_slave_event(idev->slave, I2C_SLAVE_READ_PROCESSED, &val);
+ writel(val, idev->base + SLV_DATA);
+ }
+ if (status & SLV_STATUS_SRC1)
+ i2c_slave_event(idev->slave, I2C_SLAVE_STOP, &val);
+
+ writel(INT_SLV, idev->base + INTERRUPT_STATUS);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
+{
+ struct axxia_i2c_dev *idev = _dev;
+ irqreturn_t ret = IRQ_NONE;
+ u32 status;
+
+ status = readl(idev->base + INTERRUPT_STATUS);
+
+ if (status & INT_SLV)
+ ret = axxia_i2c_slv_isr(idev);
+ if (!(status & INT_MST))
+ return ret;
+
+ /* Read interrupt status bits */
+ status = readl(idev->base + MST_INT_STATUS);
+
+ if (!idev->msg) {
+ dev_warn(idev->dev, "unexpected interrupt\n");
+ goto out;
+ }
+
+ /* RX FIFO needs service? */
+ if (i2c_m_rd(idev->msg_r) && (status & MST_STATUS_RFL))
+ axxia_i2c_empty_rx_fifo(idev);
+
+ /* TX FIFO needs service? */
+ if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
+ if (axxia_i2c_fill_tx_fifo(idev) == 0)
+ i2c_int_disable(idev, MST_STATUS_TFL);
+ }
+
+ if (unlikely(status & MST_STATUS_ERR)) {
+ /* Transfer error */
+ i2c_int_disable(idev, ~0);
+ if (status & MST_STATUS_AL)
+ idev->msg_err = -EAGAIN;
+ else if (status & MST_STATUS_NAK)
+ idev->msg_err = -ENXIO;
+ else
+ idev->msg_err = -EIO;
+ dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
+ status,
+ idev->msg->addr,
+ readl(idev->base + MST_RX_BYTES_XFRD),
+ readl(idev->base + MST_RX_XFER),
+ readl(idev->base + MST_TX_BYTES_XFRD),
+ readl(idev->base + MST_TX_XFER));
+ complete(&idev->msg_complete);
+ } else if (status & MST_STATUS_SCC) {
+ /* Stop completed */
+ i2c_int_disable(idev, ~MST_STATUS_TSS);
+ complete(&idev->msg_complete);
+ } else if (status & (MST_STATUS_SNS | MST_STATUS_SS)) {
+ /* Transfer done */
+ int mask = idev->last ? ~0 : ~MST_STATUS_TSS;
+
+ i2c_int_disable(idev, mask);
+ if (i2c_m_rd(idev->msg_r) && idev->msg_xfrd_r < idev->msg_r->len)
+ axxia_i2c_empty_rx_fifo(idev);
+ complete(&idev->msg_complete);
+ } else if (status & MST_STATUS_TSS) {
+ /* Transfer timeout */
+ idev->msg_err = -ETIMEDOUT;
+ i2c_int_disable(idev, ~MST_STATUS_TSS);
+ complete(&idev->msg_complete);
+ }
+
+out:
+ /* Clear interrupt */
+ writel(INT_MST, idev->base + INTERRUPT_STATUS);
+
+ return IRQ_HANDLED;
+}
+
+static void axxia_i2c_set_addr(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
+{
+ u32 addr_1, addr_2;
+
+ if (i2c_m_ten(msg)) {
+ /* 10-bit address
+ * addr_1: 5'b11110 | addr[9:8] | (R/nW)
+ * addr_2: addr[7:0]
+ */
+ addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
+ if (i2c_m_rd(msg))
+ addr_1 |= 1; /* Set the R/nW bit of the address */
+ addr_2 = msg->addr & 0xFF;
+ } else {
+ /* 7-bit address
+ * addr_1: addr[6:0] | (R/nW)
+ * addr_2: dont care
+ */
+ addr_1 = i2c_8bit_addr_from_msg(msg);
+ addr_2 = 0;
+ }
+
+ writel(addr_1, idev->base + MST_ADDR_1);
+ writel(addr_2, idev->base + MST_ADDR_2);
+}
+
+/* The NAK interrupt will be sent _before_ issuing STOP command
+ * so the controller might still be busy processing it. No
+ * interrupt will be sent at the end so we have to poll for it
+ */
+static int axxia_i2c_handle_seq_nak(struct axxia_i2c_dev *idev)
+{
+ unsigned long timeout = jiffies + I2C_XFER_TIMEOUT;
+
+ do {
+ if ((readl(idev->base + MST_COMMAND) & CMD_BUSY) == 0)
+ return 0;
+ usleep_range(1, 100);
+ } while (time_before(jiffies, timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int axxia_i2c_xfer_seq(struct axxia_i2c_dev *idev, struct i2c_msg msgs[])
+{
+ u32 int_mask = MST_STATUS_ERR | MST_STATUS_SS | MST_STATUS_RFL;
+ u32 rlen = i2c_m_recv_len(&msgs[1]) ? I2C_SMBUS_BLOCK_MAX : msgs[1].len;
+ unsigned long time_left;
+
+ axxia_i2c_set_addr(idev, &msgs[0]);
+
+ writel(msgs[0].len, idev->base + MST_TX_XFER);
+ writel(rlen, idev->base + MST_RX_XFER);
+
+ idev->msg = &msgs[0];
+ idev->msg_r = &msgs[1];
+ idev->msg_xfrd = 0;
+ idev->msg_xfrd_r = 0;
+ idev->last = true;
+ axxia_i2c_fill_tx_fifo(idev);
+
+ writel(CMD_SEQUENCE, idev->base + MST_COMMAND);
+
+ reinit_completion(&idev->msg_complete);
+ i2c_int_enable(idev, int_mask);
+
+ time_left = wait_for_completion_timeout(&idev->msg_complete,
+ I2C_XFER_TIMEOUT);
+
+ if (idev->msg_err == -ENXIO) {
+ if (axxia_i2c_handle_seq_nak(idev))
+ axxia_i2c_init(idev);
+ } else if (readl(idev->base + MST_COMMAND) & CMD_BUSY) {
+ dev_warn(idev->dev, "busy after xfer\n");
+ }
+
+ if (time_left == 0) {
+ idev->msg_err = -ETIMEDOUT;
+ i2c_recover_bus(&idev->adapter);
+ axxia_i2c_init(idev);
+ }
+
+ if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
+ axxia_i2c_init(idev);
+
+ return idev->msg_err;
+}
+
+static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg,
+ bool last)
+{
+ u32 int_mask = MST_STATUS_ERR;
+ u32 rx_xfer, tx_xfer;
+ unsigned long time_left;
+ unsigned int wt_value;
+
+ idev->msg = msg;
+ idev->msg_r = msg;
+ idev->msg_xfrd = 0;
+ idev->msg_xfrd_r = 0;
+ idev->last = last;
+ reinit_completion(&idev->msg_complete);
+
+ axxia_i2c_set_addr(idev, msg);
+
+ if (i2c_m_rd(msg)) {
+ /* I2C read transfer */
+ rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
+ tx_xfer = 0;
+ } else {
+ /* I2C write transfer */
+ rx_xfer = 0;
+ tx_xfer = msg->len;
+ }
+
+ writel(rx_xfer, idev->base + MST_RX_XFER);
+ writel(tx_xfer, idev->base + MST_TX_XFER);
+
+ if (i2c_m_rd(msg))
+ int_mask |= MST_STATUS_RFL;
+ else if (axxia_i2c_fill_tx_fifo(idev) != 0)
+ int_mask |= MST_STATUS_TFL;
+
+ wt_value = WT_VALUE(readl(idev->base + WAIT_TIMER_CONTROL));
+ /* Disable wait timer temporarly */
+ writel(wt_value, idev->base + WAIT_TIMER_CONTROL);
+ /* Check if timeout error happened */
+ if (idev->msg_err)
+ goto out;
+
+ if (!last) {
+ writel(CMD_MANUAL, idev->base + MST_COMMAND);
+ int_mask |= MST_STATUS_SNS;
+ } else {
+ writel(CMD_AUTO, idev->base + MST_COMMAND);
+ int_mask |= MST_STATUS_SS;
+ }
+
+ writel(WT_EN | wt_value, idev->base + WAIT_TIMER_CONTROL);
+
+ i2c_int_enable(idev, int_mask);
+
+ time_left = wait_for_completion_timeout(&idev->msg_complete,
+ I2C_XFER_TIMEOUT);
+
+ i2c_int_disable(idev, int_mask);
+
+ if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
+ dev_warn(idev->dev, "busy after xfer\n");
+
+ if (time_left == 0) {
+ idev->msg_err = -ETIMEDOUT;
+ i2c_recover_bus(&idev->adapter);
+ axxia_i2c_init(idev);
+ }
+
+out:
+ if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO &&
+ idev->msg_err != -ETIMEDOUT)
+ axxia_i2c_init(idev);
+
+ return idev->msg_err;
+}
+
+/* This function checks if the msgs[] array contains messages compatible with
+ * Sequence mode of operation. This mode assumes there will be exactly one
+ * write of non-zero length followed by exactly one read of non-zero length,
+ * both targeted at the same client device.
+ */
+static bool axxia_i2c_sequence_ok(struct i2c_msg msgs[], int num)
+{
+ return num == SEQ_LEN && !i2c_m_rd(&msgs[0]) && i2c_m_rd(&msgs[1]) &&
+ msgs[0].len > 0 && msgs[0].len <= FIFO_SIZE &&
+ msgs[1].len > 0 && msgs[0].addr == msgs[1].addr;
+}
+
+static int
+axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
+ int i;
+ int ret = 0;
+
+ idev->msg_err = 0;
+
+ if (axxia_i2c_sequence_ok(msgs, num)) {
+ ret = axxia_i2c_xfer_seq(idev, msgs);
+ return ret ? : SEQ_LEN;
+ }
+
+ i2c_int_enable(idev, MST_STATUS_TSS);
+
+ for (i = 0; ret == 0 && i < num; ++i)
+ ret = axxia_i2c_xfer_msg(idev, &msgs[i], i == (num - 1));
+
+ return ret ? : i;
+}
+
+static int axxia_i2c_get_scl(struct i2c_adapter *adap)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
+
+ return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SCLS);
+}
+
+static void axxia_i2c_set_scl(struct i2c_adapter *adap, int val)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ /* Preserve SDA Control */
+ tmp = readl(idev->base + I2C_BUS_MONITOR) & BM_SDAC;
+ if (!val)
+ tmp |= BM_SCLC;
+ writel(tmp, idev->base + I2C_BUS_MONITOR);
+}
+
+static int axxia_i2c_get_sda(struct i2c_adapter *adap)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
+
+ return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SDAS);
+}
+
+static struct i2c_bus_recovery_info axxia_i2c_recovery_info = {
+ .recover_bus = i2c_generic_scl_recovery,
+ .get_scl = axxia_i2c_get_scl,
+ .set_scl = axxia_i2c_set_scl,
+ .get_sda = axxia_i2c_get_sda,
+};
+
+static u32 axxia_i2c_func(struct i2c_adapter *adap)
+{
+ u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
+ I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
+ return caps;
+}
+
+static int axxia_i2c_reg_slave(struct i2c_client *slave)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(slave->adapter);
+ u32 slv_int_mask = SLV_STATUS_RFH;
+ u32 dec_ctl;
+
+ if (idev->slave)
+ return -EBUSY;
+
+ idev->slave = slave;
+
+ /* Enable slave mode as well */
+ writel(GLOBAL_MST_EN | GLOBAL_SLV_EN, idev->base + GLOBAL_CONTROL);
+ writel(INT_MST | INT_SLV, idev->base + INTERRUPT_ENABLE);
+
+ /* Set slave address */
+ dec_ctl = SLV_ADDR_DEC_SA1E;
+ if (slave->flags & I2C_CLIENT_TEN)
+ dec_ctl |= SLV_ADDR_DEC_SA1M;
+
+ writel(SLV_RX_ACSA1, idev->base + SLV_RX_CTL);
+ writel(dec_ctl, idev->base + SLV_ADDR_DEC_CTL);
+ writel(slave->addr, idev->base + SLV_ADDR_1);
+
+ /* Enable interrupts */
+ slv_int_mask |= SLV_STATUS_SRS1 | SLV_STATUS_SRRS1 | SLV_STATUS_SRND1;
+ slv_int_mask |= SLV_STATUS_SRC1;
+ writel(slv_int_mask, idev->base + SLV_INT_ENABLE);
+
+ return 0;
+}
+
+static int axxia_i2c_unreg_slave(struct i2c_client *slave)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(slave->adapter);
+
+ /* Disable slave mode */
+ writel(GLOBAL_MST_EN, idev->base + GLOBAL_CONTROL);
+ writel(INT_MST, idev->base + INTERRUPT_ENABLE);
+
+ synchronize_irq(idev->irq);
+
+ idev->slave = NULL;
+
+ return 0;
+}
+
+static const struct i2c_algorithm axxia_i2c_algo = {
+ .master_xfer = axxia_i2c_xfer,
+ .functionality = axxia_i2c_func,
+ .reg_slave = axxia_i2c_reg_slave,
+ .unreg_slave = axxia_i2c_unreg_slave,
+};
+
+static const struct i2c_adapter_quirks axxia_i2c_quirks = {
+ .max_read_len = 255,
+ .max_write_len = 255,
+};
+
+static int axxia_i2c_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct axxia_i2c_dev *idev = NULL;
+ void __iomem *base;
+ int ret = 0;
+
+ idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
+ if (!idev)
+ return -ENOMEM;
+
+ base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ idev->irq = platform_get_irq(pdev, 0);
+ if (idev->irq < 0)
+ return idev->irq;
+
+ idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
+ if (IS_ERR(idev->i2c_clk)) {
+ dev_err(&pdev->dev, "missing clock\n");
+ return PTR_ERR(idev->i2c_clk);
+ }
+
+ idev->base = base;
+ idev->dev = &pdev->dev;
+ init_completion(&idev->msg_complete);
+
+ of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
+ if (idev->bus_clk_rate == 0)
+ idev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ; /* default clock rate */
+
+ ret = clk_prepare_enable(idev->i2c_clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable clock\n");
+ return ret;
+ }
+
+ ret = axxia_i2c_init(idev);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to initialize\n");
+ goto error_disable_clk;
+ }
+
+ ret = devm_request_irq(&pdev->dev, idev->irq, axxia_i2c_isr, 0,
+ pdev->name, idev);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to claim IRQ%d\n", idev->irq);
+ goto error_disable_clk;
+ }
+
+ i2c_set_adapdata(&idev->adapter, idev);
+ strscpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
+ idev->adapter.owner = THIS_MODULE;
+ idev->adapter.algo = &axxia_i2c_algo;
+ idev->adapter.bus_recovery_info = &axxia_i2c_recovery_info;
+ idev->adapter.quirks = &axxia_i2c_quirks;
+ idev->adapter.dev.parent = &pdev->dev;
+ idev->adapter.dev.of_node = pdev->dev.of_node;
+
+ platform_set_drvdata(pdev, idev);
+
+ ret = i2c_add_adapter(&idev->adapter);
+ if (ret)
+ goto error_disable_clk;
+
+ return 0;
+
+error_disable_clk:
+ clk_disable_unprepare(idev->i2c_clk);
+ return ret;
+}
+
+static int axxia_i2c_remove(struct platform_device *pdev)
+{
+ struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(idev->i2c_clk);
+ i2c_del_adapter(&idev->adapter);
+
+ return 0;
+}
+
+/* Match table for of_platform binding */
+static const struct of_device_id axxia_i2c_of_match[] = {
+ { .compatible = "lsi,api2c", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
+
+static struct platform_driver axxia_i2c_driver = {
+ .probe = axxia_i2c_probe,
+ .remove = axxia_i2c_remove,
+ .driver = {
+ .name = "axxia-i2c",
+ .of_match_table = axxia_i2c_of_match,
+ },
+};
+
+module_platform_driver(axxia_i2c_driver);
+
+MODULE_DESCRIPTION("Axxia I2C Bus driver");
+MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
+MODULE_LICENSE("GPL v2");