i2c: spacemit: add support for SpacemiT K1 SoC
authorTroy Mitchell <troymitchell988@gmail.com>
Wed, 19 Mar 2025 09:29:00 +0000 (17:29 +0800)
committerAndi Shyti <andi.shyti@kernel.org>
Fri, 21 Mar 2025 00:31:03 +0000 (01:31 +0100)
This patch introduces basic I2C support for the SpacemiT K1 SoC,
utilizing interrupts for transfers.

The driver has been tested using i2c-tools on a Bananapi-F3 board,
and basic I2C read/write operations have been confirmed to work.

Signed-off-by: Troy Mitchell <troymitchell988@gmail.com>
Reviewed-by: Alex Elder <elder@riscstar.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250319-k1-i2c-master-v8-2-013e2df2b78d@gmail.com
drivers/i2c/busses/Kconfig
drivers/i2c/busses/Makefile
drivers/i2c/busses/i2c-k1.c [new file with mode: 0644]

index 0648e58b083ec5b5bffffbdf30ac2718e3ac1e85..83c88c79afe20f3589ee073431a6366995fd13b9 100644 (file)
@@ -783,6 +783,23 @@ config I2C_JZ4780
 
         If you don't know what to do here, say N.
 
+config I2C_K1
+       tristate "SpacemiT K1 I2C adapter"
+       depends on ARCH_SPACEMIT || COMPILE_TEST
+       depends on OF
+       help
+         This option enables support for the I2C interface on the SpacemiT K1
+         platform.
+
+         If you enable this configuration, the kernel will include support for
+         the I2C adapter specific to the SpacemiT K1 platform. This driver can
+         be used to manage I2C bus transactions, which are necessary for
+         interfacing with I2C peripherals such as sensors, EEPROMs, and other
+         devices.
+
+         This driver can also be built as a module.  If so, the
+         module will be called `i2c-k1`.
+
 config I2C_KEBA
        tristate "KEBA I2C controller support"
        depends on HAS_IOMEM
index 1c2a4510abe44a689dfe67d2d64cf0cf3434f510..c1252e2b779e2e47492d66179b442f2202ec0416 100644 (file)
@@ -74,6 +74,7 @@ obj-$(CONFIG_I2C_IMX)         += i2c-imx.o
 obj-$(CONFIG_I2C_IMX_LPI2C)    += i2c-imx-lpi2c.o
 obj-$(CONFIG_I2C_IOP3XX)       += i2c-iop3xx.o
 obj-$(CONFIG_I2C_JZ4780)       += i2c-jz4780.o
+obj-$(CONFIG_I2C_K1)           += i2c-k1.o
 obj-$(CONFIG_I2C_KEBA)         += i2c-keba.o
 obj-$(CONFIG_I2C_KEMPLD)       += i2c-kempld.o
 obj-$(CONFIG_I2C_LPC2K)                += i2c-lpc2k.o
diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
new file mode 100644 (file)
index 0000000..0d8763b
--- /dev/null
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024-2025 Troy Mitchell <troymitchell988@gmail.com>
+ */
+
+ #include <linux/clk.h>
+ #include <linux/i2c.h>
+ #include <linux/iopoll.h>
+ #include <linux/module.h>
+ #include <linux/of_address.h>
+ #include <linux/platform_device.h>
+
+/* spacemit i2c registers */
+#define SPACEMIT_ICR            0x0            /* Control register */
+#define SPACEMIT_ISR            0x4            /* Status register */
+#define SPACEMIT_IDBR           0xc            /* Data buffer register */
+#define SPACEMIT_IBMR           0x1c           /* Bus monitor register */
+
+/* SPACEMIT_ICR register fields */
+#define SPACEMIT_CR_START        BIT(0)                /* start bit */
+#define SPACEMIT_CR_STOP         BIT(1)                /* stop bit */
+#define SPACEMIT_CR_ACKNAK       BIT(2)                /* send ACK(0) or NAK(1) */
+#define SPACEMIT_CR_TB           BIT(3)                /* transfer byte bit */
+/* Bits 4-7 are reserved */
+#define SPACEMIT_CR_MODE_FAST    BIT(8)                /* bus mode (master operation) */
+/* Bit 9 is reserved */
+#define SPACEMIT_CR_UR           BIT(10)       /* unit reset */
+/* Bits 11-12 are reserved */
+#define SPACEMIT_CR_SCLE         BIT(13)       /* master clock enable */
+#define SPACEMIT_CR_IUE          BIT(14)       /* unit enable */
+/* Bits 15-17 are reserved */
+#define SPACEMIT_CR_ALDIE        BIT(18)       /* enable arbitration interrupt */
+#define SPACEMIT_CR_DTEIE        BIT(19)       /* enable TX interrupts */
+#define SPACEMIT_CR_DRFIE        BIT(20)       /* enable RX interrupts */
+#define SPACEMIT_CR_GCD          BIT(21)       /* general call disable */
+#define SPACEMIT_CR_BEIE         BIT(22)       /* enable bus error ints */
+/* Bits 23-24 are reserved */
+#define SPACEMIT_CR_MSDIE        BIT(25)       /* master STOP detected int enable */
+#define SPACEMIT_CR_MSDE         BIT(26)       /* master STOP detected enable */
+#define SPACEMIT_CR_TXDONEIE     BIT(27)       /* transaction done int enable */
+#define SPACEMIT_CR_TXEIE        BIT(28)       /* transmit FIFO empty int enable */
+#define SPACEMIT_CR_RXHFIE       BIT(29)       /* receive FIFO half-full int enable */
+#define SPACEMIT_CR_RXFIE        BIT(30)       /* receive FIFO full int enable */
+#define SPACEMIT_CR_RXOVIE       BIT(31)       /* receive FIFO overrun int enable */
+
+#define SPACEMIT_I2C_INT_CTRL_MASK     (SPACEMIT_CR_ALDIE | SPACEMIT_CR_DTEIE | \
+                                        SPACEMIT_CR_DRFIE | SPACEMIT_CR_BEIE | \
+                                        SPACEMIT_CR_TXDONEIE | SPACEMIT_CR_TXEIE | \
+                                        SPACEMIT_CR_RXHFIE | SPACEMIT_CR_RXFIE | \
+                                        SPACEMIT_CR_RXOVIE | SPACEMIT_CR_MSDIE)
+
+/* SPACEMIT_ISR register fields */
+/* Bits 0-13 are reserved */
+#define SPACEMIT_SR_ACKNAK       BIT(14)       /* ACK/NACK status */
+#define SPACEMIT_SR_UB           BIT(15)       /* unit busy */
+#define SPACEMIT_SR_IBB          BIT(16)       /* i2c bus busy */
+#define SPACEMIT_SR_EBB          BIT(17)       /* early bus busy */
+#define SPACEMIT_SR_ALD          BIT(18)       /* arbitration loss detected */
+#define SPACEMIT_SR_ITE          BIT(19)       /* TX buffer empty */
+#define SPACEMIT_SR_IRF          BIT(20)       /* RX buffer full */
+#define SPACEMIT_SR_GCAD         BIT(21)       /* general call address detected */
+#define SPACEMIT_SR_BED          BIT(22)       /* bus error no ACK/NAK */
+#define SPACEMIT_SR_SAD          BIT(23)       /* slave address detected */
+#define SPACEMIT_SR_SSD          BIT(24)       /* slave stop detected */
+/* Bit 25 is reserved */
+#define SPACEMIT_SR_MSD          BIT(26)       /* master stop detected */
+#define SPACEMIT_SR_TXDONE       BIT(27)       /* transaction done */
+#define SPACEMIT_SR_TXE          BIT(28)       /* TX FIFO empty */
+#define SPACEMIT_SR_RXHF         BIT(29)       /* RX FIFO half-full */
+#define SPACEMIT_SR_RXF          BIT(30)       /* RX FIFO full */
+#define SPACEMIT_SR_RXOV         BIT(31)       /* RX FIFO overrun */
+
+#define SPACEMIT_I2C_INT_STATUS_MASK   (SPACEMIT_SR_RXOV | SPACEMIT_SR_RXF | SPACEMIT_SR_RXHF | \
+                                       SPACEMIT_SR_TXE | SPACEMIT_SR_TXDONE | SPACEMIT_SR_MSD | \
+                                       SPACEMIT_SR_SSD | SPACEMIT_SR_SAD | SPACEMIT_SR_BED | \
+                                       SPACEMIT_SR_GCAD | SPACEMIT_SR_IRF | SPACEMIT_SR_ITE | \
+                                       SPACEMIT_SR_ALD)
+
+/* SPACEMIT_IBMR register fields */
+#define SPACEMIT_BMR_SDA         BIT(0)                /* SDA line level */
+#define SPACEMIT_BMR_SCL         BIT(1)                /* SCL line level */
+
+/* i2c bus recover timeout: us */
+#define SPACEMIT_I2C_BUS_BUSY_TIMEOUT          100000
+
+#define SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ    100000  /* Hz */
+#define SPACEMIT_I2C_MAX_FAST_MODE_FREQ                400000  /* Hz */
+
+#define SPACEMIT_SR_ERR        (SPACEMIT_SR_BED | SPACEMIT_SR_RXOV | SPACEMIT_SR_ALD)
+
+enum spacemit_i2c_state {
+       SPACEMIT_STATE_IDLE,
+       SPACEMIT_STATE_START,
+       SPACEMIT_STATE_READ,
+       SPACEMIT_STATE_WRITE,
+};
+
+/* i2c-spacemit driver's main struct */
+struct spacemit_i2c_dev {
+       struct device *dev;
+       struct i2c_adapter adapt;
+
+       /* hardware resources */
+       void __iomem *base;
+       int irq;
+       u32 clock_freq;
+
+       struct i2c_msg *msgs;
+       u32 msg_num;
+
+       /* index of the current message being processed */
+       u32 msg_idx;
+       u8 *msg_buf;
+       /* the number of unprocessed bytes remaining in the current message  */
+       u32 unprocessed;
+
+       enum spacemit_i2c_state state;
+       bool read;
+       struct completion complete;
+       u32 status;
+};
+
+static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c)
+{
+       u32 val;
+
+       val = readl(i2c->base + SPACEMIT_ICR);
+       val |= SPACEMIT_CR_IUE;
+       writel(val, i2c->base + SPACEMIT_ICR);
+}
+
+static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c)
+{
+       u32 val;
+
+       val = readl(i2c->base + SPACEMIT_ICR);
+       val &= ~SPACEMIT_CR_IUE;
+       writel(val, i2c->base + SPACEMIT_ICR);
+}
+
+static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c)
+{
+       writel(SPACEMIT_CR_UR, i2c->base + SPACEMIT_ICR);
+       udelay(5);
+       writel(0, i2c->base + SPACEMIT_ICR);
+}
+
+static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c)
+{
+       dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status);
+
+       if (i2c->status & (SPACEMIT_SR_BED | SPACEMIT_SR_ALD)) {
+               spacemit_i2c_reset(i2c);
+               return -EAGAIN;
+       }
+
+       return i2c->status & SPACEMIT_SR_ACKNAK ? -ENXIO : -EIO;
+}
+
+static void spacemit_i2c_conditionally_reset_bus(struct spacemit_i2c_dev *i2c)
+{
+       u32 status;
+
+       /* if bus is locked, reset unit. 0: locked */
+       status = readl(i2c->base + SPACEMIT_IBMR);
+       if ((status & SPACEMIT_BMR_SDA) && (status & SPACEMIT_BMR_SCL))
+               return;
+
+       spacemit_i2c_reset(i2c);
+       usleep_range(10, 20);
+
+       /* check scl status again */
+       status = readl(i2c->base + SPACEMIT_IBMR);
+       if (!(status & SPACEMIT_BMR_SCL))
+               dev_warn_ratelimited(i2c->dev, "unit reset failed\n");
+}
+
+static int spacemit_i2c_wait_bus_idle(struct spacemit_i2c_dev *i2c)
+{
+       int ret;
+       u32 val;
+
+       val = readl(i2c->base + SPACEMIT_ISR);
+       if (!(val & (SPACEMIT_SR_UB | SPACEMIT_SR_IBB)))
+               return 0;
+
+       ret = readl_poll_timeout(i2c->base + SPACEMIT_ISR,
+                                val, !(val & (SPACEMIT_SR_UB | SPACEMIT_SR_IBB)),
+                                1500, SPACEMIT_I2C_BUS_BUSY_TIMEOUT);
+       if (ret)
+               spacemit_i2c_reset(i2c);
+
+       return ret;
+}
+
+static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c)
+{
+       /* in case bus is not released after transfer completes */
+       if (readl(i2c->base + SPACEMIT_ISR) & SPACEMIT_SR_EBB) {
+               spacemit_i2c_conditionally_reset_bus(i2c);
+               usleep_range(90, 150);
+       }
+}
+
+static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c)
+{
+       u32 val;
+
+       /*
+        * Unmask interrupt bits for all xfer mode:
+        * bus error, arbitration loss detected.
+        * For transaction complete signal, we use master stop
+        * interrupt, so we don't need to unmask SPACEMIT_CR_TXDONEIE.
+        */
+       val = SPACEMIT_CR_BEIE | SPACEMIT_CR_ALDIE;
+
+       /*
+        * Unmask interrupt bits for interrupt xfer mode:
+        * When IDBR receives a byte, an interrupt is triggered.
+        *
+        * For the tx empty interrupt, it will be enabled in the
+        * i2c_start function.
+        * Otherwise, it will cause an erroneous empty interrupt before i2c_start.
+        */
+       val |= SPACEMIT_CR_DRFIE;
+
+       if (i2c->clock_freq == SPACEMIT_I2C_MAX_FAST_MODE_FREQ)
+               val |= SPACEMIT_CR_MODE_FAST;
+
+       /* disable response to general call */
+       val |= SPACEMIT_CR_GCD;
+
+       /* enable SCL clock output */
+       val |= SPACEMIT_CR_SCLE;
+
+       /* enable master stop detected */
+       val |= SPACEMIT_CR_MSDE | SPACEMIT_CR_MSDIE;
+
+       writel(val, i2c->base + SPACEMIT_ICR);
+}
+
+static inline void
+spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask)
+{
+       writel(mask & SPACEMIT_I2C_INT_STATUS_MASK, i2c->base + SPACEMIT_ISR);
+}
+
+static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)
+{
+       u32 target_addr_rw, val;
+       struct i2c_msg *cur_msg = i2c->msgs + i2c->msg_idx;
+
+       i2c->read = !!(cur_msg->flags & I2C_M_RD);
+
+       i2c->state = SPACEMIT_STATE_START;
+
+       target_addr_rw = (cur_msg->addr & 0x7f) << 1;
+       if (cur_msg->flags & I2C_M_RD)
+               target_addr_rw |= 1;
+
+       writel(target_addr_rw, i2c->base + SPACEMIT_IDBR);
+
+       /* send start pulse */
+       val = readl(i2c->base + SPACEMIT_ICR);
+       val &= ~SPACEMIT_CR_STOP;
+       val |= SPACEMIT_CR_START | SPACEMIT_CR_TB | SPACEMIT_CR_DTEIE;
+       writel(val, i2c->base + SPACEMIT_ICR);
+}
+
+static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c)
+{
+       u32 val;
+
+       val = readl(i2c->base + SPACEMIT_ICR);
+       val |= SPACEMIT_CR_STOP | SPACEMIT_CR_ALDIE | SPACEMIT_CR_TB;
+
+       if (i2c->read)
+               val |= SPACEMIT_CR_ACKNAK;
+
+       writel(val, i2c->base + SPACEMIT_ICR);
+}
+
+static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
+{
+       unsigned long time_left;
+       struct i2c_msg *msg;
+
+       for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
+               msg = &i2c->msgs[i2c->msg_idx];
+               i2c->msg_buf = msg->buf;
+               i2c->unprocessed = msg->len;
+               i2c->status = 0;
+
+               reinit_completion(&i2c->complete);
+
+               spacemit_i2c_start(i2c);
+
+               time_left = wait_for_completion_timeout(&i2c->complete,
+                                                       i2c->adapt.timeout);
+               if (!time_left) {
+                       dev_err(i2c->dev, "msg completion timeout\n");
+                       spacemit_i2c_conditionally_reset_bus(i2c);
+                       spacemit_i2c_reset(i2c);
+                       return -ETIMEDOUT;
+               }
+
+               if (i2c->status & SPACEMIT_SR_ERR)
+                       return spacemit_i2c_handle_err(i2c);
+       }
+
+       return 0;
+}
+
+static bool spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c)
+{
+       if (i2c->msg_idx != i2c->msg_num - 1)
+               return false;
+
+       if (i2c->read)
+               return i2c->unprocessed == 1;
+
+       return !i2c->unprocessed;
+}
+
+static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c)
+{
+       /* if transfer completes, SPACEMIT_ISR will handle it */
+       if (i2c->status & SPACEMIT_SR_MSD)
+               return;
+
+       if (i2c->unprocessed) {
+               writel(*i2c->msg_buf++, i2c->base + SPACEMIT_IDBR);
+               i2c->unprocessed--;
+               return;
+       }
+
+       /* SPACEMIT_STATE_IDLE avoids trigger next byte */
+       i2c->state = SPACEMIT_STATE_IDLE;
+       complete(&i2c->complete);
+}
+
+static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c)
+{
+       if (i2c->unprocessed) {
+               *i2c->msg_buf++ = readl(i2c->base + SPACEMIT_IDBR);
+               i2c->unprocessed--;
+       }
+
+       /* if transfer completes, SPACEMIT_ISR will handle it */
+       if (i2c->status & (SPACEMIT_SR_MSD | SPACEMIT_SR_ACKNAK))
+               return;
+
+       /* it has to append stop bit in icr that read last byte */
+       if (i2c->unprocessed)
+               return;
+
+       /* SPACEMIT_STATE_IDLE avoids trigger next byte */
+       i2c->state = SPACEMIT_STATE_IDLE;
+       complete(&i2c->complete);
+}
+
+static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c)
+{
+       i2c->state = i2c->read ? SPACEMIT_STATE_READ : SPACEMIT_STATE_WRITE;
+       if (i2c->state == SPACEMIT_STATE_WRITE)
+               spacemit_i2c_handle_write(i2c);
+}
+
+static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c)
+{
+       u32 val;
+
+       /*
+        * Send transaction complete signal:
+        * error happens, detect master stop
+        */
+       if (!(i2c->status & (SPACEMIT_SR_ERR | SPACEMIT_SR_MSD)))
+               return;
+
+       /*
+        * Here the transaction is already done, we don't need any
+        * other interrupt signals from now, in case any interrupt
+        * happens before spacemit_i2c_xfer to disable irq and i2c unit,
+        * we mask all the interrupt signals and clear the interrupt
+        * status.
+        */
+       val = readl(i2c->base + SPACEMIT_ICR);
+       val &= ~SPACEMIT_I2C_INT_CTRL_MASK;
+       writel(val, i2c->base + SPACEMIT_ICR);
+
+       spacemit_i2c_clear_int_status(i2c, SPACEMIT_I2C_INT_STATUS_MASK);
+
+       i2c->state = SPACEMIT_STATE_IDLE;
+       complete(&i2c->complete);
+}
+
+static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
+{
+       struct spacemit_i2c_dev *i2c = devid;
+       u32 status, val;
+
+       status = readl(i2c->base + SPACEMIT_ISR);
+       if (!status)
+               return IRQ_HANDLED;
+
+       i2c->status = status;
+
+       spacemit_i2c_clear_int_status(i2c, status);
+
+       if (i2c->status & SPACEMIT_SR_ERR)
+               goto err_out;
+
+       val = readl(i2c->base + SPACEMIT_ICR);
+       val &= ~(SPACEMIT_CR_TB | SPACEMIT_CR_ACKNAK | SPACEMIT_CR_STOP | SPACEMIT_CR_START);
+       writel(val, i2c->base + SPACEMIT_ICR);
+
+       switch (i2c->state) {
+       case SPACEMIT_STATE_START:
+               spacemit_i2c_handle_start(i2c);
+               break;
+       case SPACEMIT_STATE_READ:
+               spacemit_i2c_handle_read(i2c);
+               break;
+       case SPACEMIT_STATE_WRITE:
+               spacemit_i2c_handle_write(i2c);
+               break;
+       default:
+               break;
+       }
+
+       if (i2c->state != SPACEMIT_STATE_IDLE) {
+               if (spacemit_i2c_is_last_msg(i2c)) {
+                       /* trigger next byte with stop */
+                       spacemit_i2c_stop(i2c);
+               } else {
+                       /* trigger next byte */
+                       val |= SPACEMIT_CR_ALDIE | SPACEMIT_CR_TB;
+                       writel(val, i2c->base + SPACEMIT_ICR);
+               }
+       }
+
+err_out:
+       spacemit_i2c_err_check(i2c);
+       return IRQ_HANDLED;
+}
+
+static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c)
+{
+       unsigned long timeout;
+       int idx = 0, cnt = 0;
+
+       for (; idx < i2c->msg_num; idx++)
+               cnt += (i2c->msgs + idx)->len + 1;
+
+       /*
+        * Multiply by 9 because each byte in I2C transmission requires
+        * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit.
+        */
+       timeout = cnt * 9 * USEC_PER_SEC / i2c->clock_freq;
+
+       i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 10) / i2c->msg_num;
+}
+
+static int spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg *msgs, int num)
+{
+       struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt);
+       int ret;
+
+       i2c->msgs = msgs;
+       i2c->msg_num = num;
+
+       spacemit_i2c_calc_timeout(i2c);
+
+       spacemit_i2c_init(i2c);
+
+       spacemit_i2c_enable(i2c);
+
+       ret = spacemit_i2c_wait_bus_idle(i2c);
+       if (!ret)
+               spacemit_i2c_xfer_msg(i2c);
+       else if (ret < 0)
+               dev_dbg(i2c->dev, "i2c transfer error: %d\n", ret);
+       else
+               spacemit_i2c_check_bus_release(i2c);
+
+       spacemit_i2c_disable(i2c);
+
+       if (ret == -ETIMEDOUT || ret == -EAGAIN)
+               dev_err(i2c->dev, "i2c transfer failed, ret %d err 0x%lx\n",
+                         ret, i2c->status & SPACEMIT_SR_ERR);
+
+       return ret < 0 ? ret : num;
+}
+
+static u32 spacemit_i2c_func(struct i2c_adapter *adap)
+{
+       return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static const struct i2c_algorithm spacemit_i2c_algo = {
+       .xfer = spacemit_i2c_xfer,
+       .functionality = spacemit_i2c_func,
+};
+
+static int spacemit_i2c_probe(struct platform_device *pdev)
+{
+       struct clk *clk;
+       struct device *dev = &pdev->dev;
+       struct device_node *of_node = pdev->dev.of_node;
+       struct spacemit_i2c_dev *i2c;
+       int ret;
+
+       i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+       if (!i2c)
+               return -ENOMEM;
+
+       of_property_read_u32(of_node, "clock-frequency", &i2c->clock_freq);
+       if (ret && ret != -EINVAL)
+               dev_warn(dev, "failed to read clock-frequency property: %d\n", ret);
+
+       /* For now, this driver doesn't support high-speed. */
+       if (!i2c->clock_freq || i2c->clock_freq > SPACEMIT_I2C_MAX_FAST_MODE_FREQ) {
+               dev_warn(dev, "unsupported clock frequency %u; using %u\n",
+                        i2c->clock_freq, SPACEMIT_I2C_MAX_FAST_MODE_FREQ);
+               i2c->clock_freq = SPACEMIT_I2C_MAX_FAST_MODE_FREQ;
+       } else if (i2c->clock_freq < SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ) {
+               dev_warn(dev, "unsupported clock frequency %u; using %u\n",
+                        i2c->clock_freq,  SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ);
+               i2c->clock_freq = SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ;
+       }
+
+       i2c->dev = &pdev->dev;
+
+       i2c->base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(i2c->base))
+               return dev_err_probe(dev, PTR_ERR(i2c->base), "failed to do ioremap");
+
+       i2c->irq = platform_get_irq(pdev, 0);
+       if (i2c->irq < 0)
+               return dev_err_probe(dev, i2c->irq, "failed to get irq resource");
+
+       ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
+                              IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
+       if (ret)
+               return dev_err_probe(dev, ret, "failed to request irq");
+
+       clk = devm_clk_get_enabled(dev, "func");
+       if (IS_ERR(clk))
+               return dev_err_probe(dev, PTR_ERR(clk), "failed to enable func clock");
+
+       clk = devm_clk_get_enabled(dev, "bus");
+       if (IS_ERR(clk))
+               return dev_err_probe(dev, PTR_ERR(clk), "failed to enable bus clock");
+
+       spacemit_i2c_reset(i2c);
+
+       i2c_set_adapdata(&i2c->adapt, i2c);
+       i2c->adapt.owner = THIS_MODULE;
+       i2c->adapt.algo = &spacemit_i2c_algo;
+       i2c->adapt.dev.parent = i2c->dev;
+       i2c->adapt.nr = pdev->id;
+
+       i2c->adapt.dev.of_node = of_node;
+
+       strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
+
+       init_completion(&i2c->complete);
+
+       platform_set_drvdata(pdev, i2c);
+
+       ret = i2c_add_numbered_adapter(&i2c->adapt);
+       if (ret)
+               return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
+
+       return 0;
+}
+
+static void spacemit_i2c_remove(struct platform_device *pdev)
+{
+       struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
+
+       i2c_del_adapter(&i2c->adapt);
+}
+
+static const struct of_device_id spacemit_i2c_of_match[] = {
+       { .compatible = "spacemit,k1-i2c", },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
+
+static struct platform_driver spacemit_i2c_driver = {
+       .probe = spacemit_i2c_probe,
+       .remove = spacemit_i2c_remove,
+       .driver = {
+               .name = "i2c-k1",
+               .of_match_table = spacemit_i2c_of_match,
+       },
+};
+module_platform_driver(spacemit_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");