* [PATCH v2 2/3] i2c: ma35d1: Add Nuvoton MA35D1 I2C driver support
2026-03-16 6:37 [PATCH v2 0/3] i2c: ma35d1: Add support for MA35D1 I2C controller Zi-Yu Chen
2026-03-16 6:37 ` [PATCH v2 1/3] dt-bindings: i2c: nuvoton,ma35d1-i2c: Add " Zi-Yu Chen
@ 2026-03-16 6:37 ` Zi-Yu Chen
2026-03-16 6:37 ` [PATCH v2 3/3] arm64: dts: nuvoton: Add I2C nodes for MA35D1 SoC Zi-Yu Chen
2 siblings, 0 replies; 4+ messages in thread
From: Zi-Yu Chen @ 2026-03-16 6:37 UTC (permalink / raw)
To: andi.shyti, ychuang3
Cc: robh, krzk+dt, conor+dt, linux-i2c, devicetree, linux-arm-kernel,
zychennvt
Add I2C support for Nuvoton MA35D1 SoC.
The controller supports standard, fast and fast-plus modes,
and provides controller/target functionality.
Signed-off-by: Zi-Yu Chen <zychennvt@gmail.com>
---
drivers/i2c/busses/Kconfig | 13 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-ma35d1.c | 792 ++++++++++++++++++++++++++++++++
3 files changed, 806 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-ma35d1.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index e11d50750e63..b265b785d058 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1589,4 +1589,17 @@ config I2C_VIRTIO
This driver can also be built as a module. If so, the module
will be called i2c-virtio.
+config I2C_MA35D1
+ tristate "Nuvoton MA35D1 I2C driver"
+ depends on ARCH_MA35 || COMPILE_TEST
+ select I2C_SLAVE
+ help
+ If you say yes to this option, support will be included for the
+ I2C controller in the Nuvoton MA35D1 SoC. This driver
+ supports the standard I2C bus protocols, including master and
+ slave modes.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-ma35d1.
+
endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 547123ab351f..264f6f3f608d 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -130,6 +130,7 @@ obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
obj-$(CONFIG_I2C_XLP9XX) += i2c-xlp9xx.o
obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o
obj-$(CONFIG_I2C_GXP) += i2c-gxp.o
+obj-$(CONFIG_I2C_MA35D1) += i2c-ma35d1.o
# External I2C/SMBus adapter drivers
obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o
diff --git a/drivers/i2c/busses/i2c-ma35d1.c b/drivers/i2c/busses/i2c-ma35d1.c
new file mode 100644
index 000000000000..c643f406e000
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ma35d1.c
@@ -0,0 +1,792 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2026 Nuvoton technology corporation.
+ *
+ * Author: Zi-Yu Chen <zychennvt@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+/* MA35D1 I2C registers offset */
+#define MA35_CTL0 0x00
+#define MA35_ADDR0 0x04
+#define MA35_DAT 0x08
+#define MA35_STATUS0 0x0c
+#define MA35_CLKDIV 0x10
+#define MA35_TOCTL 0x14
+#define MA35_ADDR1 0x18
+#define MA35_ADDR2 0x1c
+#define MA35_ADDR3 0x20
+#define MA35_ADDRMSK0 0x24
+#define MA35_ADDRMSK1 0x28
+#define MA35_ADDRMSK2 0x2c
+#define MA35_ADDRMSK3 0x30
+#define MA35_WKCTL 0x3c
+#define MA35_WKSTS 0x40
+#define MA35_CTL1 0x44
+#define MA35_STATUS1 0x48
+#define MA35_TMCTL 0x4c
+#define MA35_BUSCTL 0x50
+#define MA35_BUSTCTL 0x54
+#define MA35_BUSSTS 0x58
+#define MA35_PKTSIZE 0x5c
+#define MA35_PKTCRC 0x60
+#define MA35_BUSTOUT 0x64
+#define MA35_CLKTOUT 0x68
+#define MA35_AUTOCNT 0x78
+
+/* MA35D1 I2C Status */
+/* Controller */
+#define MA35_M_START 0x08 /* Start */
+#define MA35_M_REPEAT_START 0x10 /* Controller Repeat Start */
+#define MA35_M_TRAN_ADDR_ACK 0x18 /* Controller Transmit Address ACK */
+#define MA35_M_TRAN_ADDR_NACK 0x20 /* Controller Transmit Address NACK */
+#define MA35_M_TRAN_DATA_ACK 0x28 /* Controller Transmit Data ACK */
+#define MA35_M_TRAN_DATA_NACK 0x30 /* Controller Transmit Data NACK */
+#define MA35_M_ARB_LOST 0x38 /* Controller Arbitration Lost */
+#define MA35_M_RECE_ADDR_ACK 0x40 /* Controller Receive Address ACK */
+#define MA35_M_RECE_ADDR_NACK 0x48 /* Controller Receive Address NACK */
+#define MA35_M_RECE_DATA_ACK 0x50 /* Controller Receive Data ACK */
+#define MA35_M_RECE_DATA_NACK 0x58 /* Controller Receive Data NACK */
+#define MA35_BUS_ERROR 0x00 /* Bus error */
+
+/* Target */
+#define MA35_S_REPEAT_START_STOP 0xa0 /* Target Transmit Repeat Start or Stop */
+#define MA35_S_TRAN_ADDR_ACK 0xa8 /* Target Transmit Address ACK */
+#define MA35_S_TRAN_DATA_ACK 0xb8 /* Target Transmit Data ACK */
+#define MA35_S_TRAN_DATA_NACK 0xc0 /* Target Transmit Data NACK */
+#define MA35_S_TRAN_LAST_DATA_ACK 0xc8 /* Target Transmit Last Data ACK */
+#define MA35_S_RECE_ADDR_ACK 0x60 /* Target Receive Address ACK */
+#define MA35_S_RECE_ARB_LOST 0x68 /* Target Receive Arbitration Lost */
+#define MA35_S_RECE_DATA_ACK 0x80 /* Target Receive Data ACK */
+#define MA35_S_RECE_DATA_NACK 0x88 /* Target Receive Data NACK */
+
+/* GC Mode */
+#define MA35_GC_ADDR_ACK 0x70 /* GC mode Address ACK */
+#define MA35_GC_ARB_LOST 0x78 /* GC mode Arbitration Lost */
+#define MA35_GC_DATA_ACK 0x90 /* GC mode Data ACK */
+#define MA35_GC_DATA_NACK 0x98 /* GC mode Data NACK */
+
+/* Other */
+#define MA35_ADDR_TRAN_ARB_LOST 0xb0 /* Address Transmit Arbitration Lost */
+#define MA35_BUS_RELEASED 0xf8 /* Bus Released */
+
+/* I2C_CTL constant definitions. */
+#define MA35_CTL_AA BIT(2)
+#define MA35_CTL_SI BIT(3)
+#define MA35_CTL_STO BIT(4)
+#define MA35_CTL_STA BIT(5)
+#define MA35_CTL_I2CEN BIT(6)
+#define MA35_CTL_INTEN BIT(7)
+#define MA35_CTL_SI_AA (MA35_CTL_SI | MA35_CTL_AA)
+#define MA35_CTL_STO_SI (MA35_CTL_STO | MA35_CTL_SI)
+#define MA35_CTL_STA_SI (MA35_CTL_STA | MA35_CTL_SI)
+#define MA35_CTL_STA_SI_AA (MA35_CTL_STA | MA35_CTL_SI | MA35_CTL_AA)
+#define MA35_CTL_STO_SI_AA (MA35_CTL_STO | MA35_CTL_SI | MA35_CTL_AA)
+
+/* Constants */
+#define MA35_CLKDIV_MSK GENMASK(15, 0)
+#define MA35_I2C_ADDR_MASK (0x7f << 1)
+#define I2C_PM_TIMEOUT_MS 5000
+#define STOP_TIMEOUT_MS 50
+#define MA35_I2C_GC_EN 1
+#define MA35_I2C_GC_DIS 0
+
+struct ma35d1_i2c {
+ spinlock_t lock; /* Protects I2C register access and state */
+ wait_queue_head_t wait;
+ struct i2c_msg *msg;
+ unsigned int msg_num;
+ unsigned int msg_idx;
+ unsigned int msg_ptr;
+ unsigned int irq;
+ unsigned int arblost;
+ void __iomem *regs;
+ struct clk *clk;
+ struct device *dev;
+ struct i2c_adapter adap;
+ struct i2c_client *target;
+ struct reset_control *rst;
+};
+
+static inline bool ma35d1_is_controller_status(unsigned int status)
+{
+ return status >= MA35_M_START && status <= MA35_M_RECE_DATA_NACK;
+}
+
+/*
+ * ma35d1_i2c_write_CTL - Update the I2C control register
+ * @i2c: Pointer to the ma35d1 i2c instance
+ * @ctl: Control bits to set (e.g., MA35_CTL_STA, SI, AA)
+ *
+ * This helper reads CTL0, clears the sticky state-change bits (STA, STO, SI, AA),
+ * and then applies the new control bits provided by @ctl.
+ */
+static void ma35d1_i2c_write_CTL(struct ma35d1_i2c *i2c, unsigned int ctl)
+{
+ unsigned int val;
+
+ val = readl(i2c->regs + MA35_CTL0);
+ val &= ~(MA35_CTL_STA_SI_AA | MA35_CTL_STO);
+ val |= ctl;
+ writel(val, i2c->regs + MA35_CTL0);
+}
+
+static void ma35d1_i2c_set_addr(struct ma35d1_i2c *i2c)
+{
+ unsigned int rw = i2c->msg->flags & I2C_M_RD;
+
+ writel(((i2c->msg->addr & 0x7f) << 1) | rw, i2c->regs + MA35_DAT);
+}
+
+static void ma35d1_i2c_controller_complete(struct ma35d1_i2c *i2c, int ret)
+{
+ dev_dbg(i2c->dev, "controller_complete %d\n", ret);
+
+ i2c->msg_ptr = 0;
+ i2c->msg = NULL;
+ i2c->msg_idx++;
+ i2c->msg_num = 0;
+ if (ret)
+ i2c->msg_idx = ret;
+
+ wake_up(&i2c->wait);
+}
+
+static void ma35d1_i2c_disable_irq(struct ma35d1_i2c *i2c)
+{
+ unsigned long tmp;
+
+ tmp = readl(i2c->regs + MA35_CTL0);
+ writel(tmp & ~MA35_CTL_INTEN, i2c->regs + MA35_CTL0);
+}
+
+static void ma35d1_i2c_enable_irq(struct ma35d1_i2c *i2c)
+{
+ unsigned long tmp;
+
+ tmp = readl(i2c->regs + MA35_CTL0);
+ writel(tmp | MA35_CTL_INTEN, i2c->regs + MA35_CTL0);
+}
+
+static void ma35d1_i2c_reset(struct ma35d1_i2c *i2c)
+{
+ unsigned int tmp;
+
+ tmp = readl(i2c->regs + MA35_CLKDIV);
+
+ reset_control_assert(i2c->rst);
+ usleep_range(10, 20);
+ reset_control_deassert(i2c->rst);
+
+ writel(tmp, (i2c->regs + MA35_CLKDIV));
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_I2CEN);
+
+ if (i2c->target)
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI_AA);
+}
+
+static void ma35d1_i2c_stop(struct ma35d1_i2c *i2c, int ret)
+{
+ unsigned int val;
+ int err;
+
+ /* Ensure AA is cleared to prevent the controller
+ * from re-claiming the bus unnecessarily
+ */
+ if (readl(i2c->regs + MA35_CTL0) & MA35_CTL_AA) {
+ val = readl(i2c->regs + MA35_CTL0);
+ val &= ~MA35_CTL_AA;
+ writel(val, (i2c->regs + MA35_CTL0));
+
+ err = readl_poll_timeout_atomic(i2c->regs + MA35_CTL0, val,
+ !(val & MA35_CTL_AA), 1, 1000);
+ if (err)
+ dev_warn(i2c->dev,
+ "AA bit could not be cleared in time\n");
+ }
+
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_STO_SI);
+
+ err = readl_poll_timeout_atomic(i2c->regs + MA35_CTL0, val,
+ !(val & MA35_CTL_STO), 1, 1 * 1000);
+ if (err)
+ dev_warn(i2c->dev, "I2C Stop Timeout\n");
+
+ if (i2c->target)
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI_AA);
+ else
+ ma35d1_i2c_disable_irq(i2c);
+
+ ma35d1_i2c_controller_complete(i2c, ret);
+}
+
+/* Check if this is the last message in the set */
+static inline bool is_last_msg(struct ma35d1_i2c *i2c)
+{
+ return i2c->msg_idx >= (i2c->msg_num - 1);
+}
+
+/* Check if this is the last byte in the current message */
+static inline bool is_last_byte(struct ma35d1_i2c *i2c)
+{
+ return i2c->msg_ptr == i2c->msg->len - 1;
+}
+
+/* Check if reached the end of the current message */
+static inline bool is_msgend(struct ma35d1_i2c *i2c)
+{
+ return i2c->msg_ptr >= i2c->msg->len;
+}
+
+/*
+ * i2c_ma35d1_irq_target_trx - I2C Target state machine handler
+ * @i2c: ma35d1 i2c instance
+ * @i2c_status: hardware status code from MA35_STATUS0
+ */
+static void i2c_ma35d1_irq_target_trx(struct ma35d1_i2c *i2c,
+ unsigned long i2c_status)
+{
+ unsigned char byte;
+
+ switch (i2c_status) {
+ case MA35_S_RECE_ADDR_ACK:
+ /* Own SLA+W has been receive; ACK has been return */
+ i2c_slave_event(i2c->target, I2C_SLAVE_WRITE_REQUESTED, &byte);
+ break;
+ case MA35_S_TRAN_DATA_NACK:
+ /* Data byte or last data in I2CDAT has been transmitted.
+ * Not ACK has been received
+ */
+ case MA35_S_RECE_DATA_NACK:
+ /* Previously addressed with own SLA address;
+ * NOT ACK has been returned
+ */
+ break;
+
+ case MA35_S_RECE_DATA_ACK:
+ /* Previously address with own SLA address Data has been received;
+ * ACK has been returned
+ */
+ byte = readb(i2c->regs + MA35_DAT);
+ i2c_slave_event(i2c->target, I2C_SLAVE_WRITE_RECEIVED, &byte);
+ break;
+
+ case MA35_S_TRAN_ADDR_ACK:
+ /* Own SLA+R has been receive; ACK has been return */
+ i2c_slave_event(i2c->target, I2C_SLAVE_READ_REQUESTED, &byte);
+
+ writel(byte, i2c->regs + MA35_DAT);
+ break;
+
+ case MA35_S_TRAN_DATA_ACK:
+ i2c_slave_event(i2c->target, I2C_SLAVE_READ_PROCESSED, &byte);
+ writel(byte, i2c->regs + MA35_DAT);
+ break;
+
+ case MA35_S_REPEAT_START_STOP:
+ /* A STOP or repeated START has been received
+ * while still addressed as Target/Receiver
+ */
+ i2c_slave_event(i2c->target, I2C_SLAVE_STOP, &byte);
+ break;
+
+ default:
+ dev_err(i2c->dev, "Status 0x%02lx is NOT processed\n",
+ i2c_status);
+ break;
+ }
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI_AA);
+}
+
+/*
+ * i2c_ma35d1_irq_controller_trx - I2C Controller state machine handler
+ * @i2c: ma35d1 i2c instance
+ * @i2c_status: hardware status code from MA35_STATUS0
+ */
+static void i2c_ma35d1_irq_controller_trx(struct ma35d1_i2c *i2c,
+ unsigned long i2c_status)
+{
+ unsigned char byte;
+
+ switch (i2c_status) {
+ case MA35_M_START:
+ case MA35_M_REPEAT_START:
+ ma35d1_i2c_set_addr(i2c);
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI);
+ break;
+
+ case MA35_M_TRAN_ADDR_ACK:
+ case MA35_M_TRAN_DATA_ACK:
+ /* SLA+W has been transmitted and ACK has been received */
+ if (i2c_status == MA35_M_TRAN_ADDR_ACK) {
+ if (is_last_msg(i2c) && i2c->msg->len == 0) {
+ ma35d1_i2c_stop(i2c, 0);
+ return;
+ }
+ }
+
+ if (!is_msgend(i2c)) {
+ byte = i2c->msg->buf[i2c->msg_ptr++];
+ writel(byte, i2c->regs + MA35_DAT);
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI);
+ } else if (!is_last_msg(i2c)) {
+ dev_dbg(i2c->dev, "WRITE: Next Message\n");
+
+ i2c->msg_ptr = 0;
+ i2c->msg_idx++;
+ i2c->msg++;
+
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_STA | MA35_CTL_SI);
+ } else {
+ ma35d1_i2c_stop(i2c, 0);
+ }
+ break;
+
+ case MA35_M_TRAN_DATA_NACK:
+ ma35d1_i2c_stop(i2c, 0);
+ break;
+
+ case MA35_M_TRAN_ADDR_NACK:
+ case MA35_M_RECE_ADDR_NACK:
+ /* Controller Transmit Address NACK */
+ /* 0x20: SLA+W has been transmitted and NACK has been received */
+ /* 0x48: SLA+R has been transmitted and NACK has been received */
+ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
+ dev_dbg(i2c->dev, "\n i2c: ack was not received\n");
+ ma35d1_i2c_stop(i2c, -ENXIO);
+ }
+ break;
+
+ case MA35_M_RECE_ADDR_ACK:
+ if (is_last_msg(i2c) && i2c->msg->len == 0)
+ ma35d1_i2c_stop(i2c, 0);
+ else if (is_last_msg(i2c) && (i2c->msg->len == 1))
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI);
+ else
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI_AA);
+ break;
+
+ case MA35_M_RECE_DATA_ACK:
+ case MA35_M_RECE_DATA_NACK:
+ /* DATA has been transmitted and ACK has been received */
+ byte = readb(i2c->regs + MA35_DAT);
+ i2c->msg->buf[i2c->msg_ptr++] = byte;
+
+ if (is_last_byte(i2c)) {
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI);
+ } else if (is_msgend(i2c)) {
+ if (is_last_msg(i2c)) {
+ dev_dbg(i2c->dev, "READ: Send Stop\n");
+
+ ma35d1_i2c_stop(i2c, 0);
+ } else {
+ dev_dbg(i2c->dev, "READ: Next Transfer\n");
+
+ i2c->msg_ptr = 0;
+ i2c->msg_idx++;
+ i2c->msg++;
+
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_STA_SI);
+ }
+ } else {
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI_AA);
+ }
+ break;
+
+ default:
+ dev_err(i2c->dev, "Status 0x%02lx is NOT processed\n",
+ i2c_status);
+ ma35d1_i2c_disable_irq(i2c);
+ ma35d1_i2c_stop(i2c, 0);
+ break;
+ }
+}
+
+static irqreturn_t ma35d1_i2c_irq(int irqno, void *dev_id)
+{
+ struct ma35d1_i2c *i2c = dev_id;
+ unsigned long status, flags;
+
+ status = readl(i2c->regs + MA35_STATUS0);
+
+ spin_lock_irqsave(&i2c->lock, flags);
+
+ if (status == MA35_M_ARB_LOST) {
+ dev_err(i2c->dev, "Arbitration lost\n");
+ i2c->arblost = 1;
+ ma35d1_i2c_disable_irq(i2c);
+ ma35d1_i2c_stop(i2c, -EAGAIN);
+ goto out;
+ }
+
+ else if (status == MA35_BUS_ERROR) {
+ dev_err(i2c->dev, "Bus error during transfer\n");
+ ma35d1_i2c_disable_irq(i2c);
+ ma35d1_i2c_stop(i2c, 0);
+ goto out;
+ }
+
+ if (ma35d1_is_controller_status(status))
+ i2c_ma35d1_irq_controller_trx(i2c, status);
+ else
+ i2c_ma35d1_irq_target_trx(i2c, status);
+
+out:
+ spin_unlock_irqrestore(&i2c->lock, flags);
+ return IRQ_HANDLED;
+}
+
+static int ma35d1_i2c_doxfer(struct ma35d1_i2c *i2c, struct i2c_msg *msgs,
+ int num)
+{
+ unsigned long timeout;
+ unsigned int val;
+ int ret, err;
+
+ spin_lock_irq(&i2c->lock);
+
+ ma35d1_i2c_enable_irq(i2c);
+
+ i2c->msg = msgs;
+ i2c->msg_num = num;
+ i2c->msg_ptr = 0;
+ i2c->msg_idx = 0;
+
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI | MA35_CTL_STA);
+ spin_unlock_irq(&i2c->lock);
+
+ timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
+ ret = i2c->msg_idx;
+
+ if (timeout == 0)
+ dev_dbg(i2c->dev, "timeout\n");
+ else if (ret != num)
+ dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
+
+ err = readl_poll_timeout(i2c->regs + MA35_CTL0, val,
+ !(val & MA35_CTL_STO), 100,
+ STOP_TIMEOUT_MS * 1000);
+
+ if (err) {
+ dev_err(i2c->dev, "Bus stuck! Resetting controller...\n");
+ ma35d1_i2c_reset(i2c);
+ }
+
+ if (i2c->arblost) {
+ dev_dbg(i2c->dev, "arb lost, stop\n");
+ i2c->arblost = 0;
+ }
+
+ return ret;
+}
+
+static int ma35d1_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct ma35d1_i2c *i2c = i2c_get_adapdata(adap);
+ int retry, ret;
+
+ ret = pm_runtime_resume_and_get(i2c->dev);
+ if (ret)
+ return ret;
+
+ for (retry = 0; retry < adap->retries; retry++) {
+ ret = ma35d1_i2c_doxfer(i2c, msgs, num);
+
+ if (ret != -EAGAIN)
+ break;
+
+ dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
+ fsleep(100);
+ }
+
+ if (ret == -EAGAIN)
+ ret = -EREMOTEIO;
+
+ pm_runtime_put_autosuspend(i2c->dev);
+
+ return ret;
+}
+
+static int ma35d1_reg_target(struct i2c_client *target)
+{
+ struct ma35d1_i2c *i2c = i2c_get_adapdata(target->adapter);
+ unsigned int val, slvaddr;
+ int ret;
+
+ if (i2c->target)
+ return -EBUSY;
+
+ if (target->flags & I2C_CLIENT_TEN)
+ return -EAFNOSUPPORT;
+
+ ma35d1_i2c_enable_irq(i2c);
+
+ ret = pm_runtime_resume_and_get(i2c->dev);
+ if (ret) {
+ dev_err(i2c->dev, "failed to resume i2c controller\n");
+ return ret;
+ }
+
+ i2c->target = target;
+
+ val = readl(i2c->regs + MA35_CTL0);
+ val |= MA35_CTL_I2CEN;
+ writel(val, i2c->regs + MA35_CTL0);
+ slvaddr = target->addr << 1;
+ writel(slvaddr, i2c->regs + MA35_ADDR0);
+
+ /* I2C enter SLV mode */
+ ma35d1_i2c_write_CTL(i2c, MA35_CTL_SI_AA);
+
+ return 0;
+}
+
+static int ma35d1_unreg_target(struct i2c_client *target)
+{
+ struct ma35d1_i2c *i2c = i2c_get_adapdata(target->adapter);
+ unsigned int val;
+ int ret;
+
+ /* Disable I2C */
+ val = readl(i2c->regs + MA35_CTL0);
+ val &= ~MA35_CTL_I2CEN;
+ writel(val, i2c->regs + MA35_CTL0);
+
+ /* Disable I2C interrupt */
+ ma35d1_i2c_disable_irq(i2c);
+
+ i2c->target = NULL;
+
+ ret = pm_runtime_put_sync(i2c->dev);
+ if (ret)
+ dev_err(i2c->dev, "failed to suspend i2c controller");
+
+ return 0;
+}
+
+/* Declare Our I2C Functionality */
+static u32 ma35d1_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_SMBUS_EMUL;
+}
+
+/* I2C Bus Registration Info */
+static const struct i2c_algorithm ma35d1_i2c_algorithm = {
+ .xfer = ma35d1_i2c_xfer,
+ .functionality = ma35d1_i2c_func,
+ .reg_target = ma35d1_reg_target,
+ .unreg_target = ma35d1_unreg_target,
+};
+
+static int ma35d1_i2c_probe(struct platform_device *pdev)
+{
+ struct ma35d1_i2c *i2c;
+ struct resource *res;
+ int ret, clkdiv;
+ unsigned int busfreq;
+ struct device *dev = &pdev->dev;
+
+ i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ spin_lock_init(&i2c->lock);
+ init_waitqueue_head(&i2c->wait);
+
+ i2c->dev = dev;
+
+ i2c->clk = devm_clk_get_prepared(dev, NULL);
+ if (IS_ERR(i2c->clk))
+ return dev_err_probe(dev, PTR_ERR(i2c->clk),
+ "failed to get core clk\n");
+
+ i2c->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(i2c->regs))
+ return PTR_ERR(i2c->regs);
+
+ i2c->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(i2c->rst))
+ return dev_err_probe(dev, PTR_ERR(i2c->rst),
+ "failed to get reset control\n");
+
+ /* Setup info block for the I2C core */
+ strscpy(i2c->adap.name, "ma35d1-i2c", sizeof(i2c->adap.name));
+ i2c->adap.owner = THIS_MODULE;
+ i2c->adap.algo = &ma35d1_i2c_algorithm;
+ i2c->adap.retries = 2;
+ i2c->adap.algo_data = i2c;
+ i2c->adap.dev.parent = &pdev->dev;
+ i2c->adap.dev.of_node = pdev->dev.of_node;
+ i2c_set_adapdata(&i2c->adap, i2c);
+
+ /* Default to 100kHz if not specified in DT */
+ busfreq = 100000;
+ device_property_read_u32(dev, "clock-frequency", &busfreq);
+
+ /* Calculate divider based on the current peripheral clock rate */
+ clkdiv = DIV_ROUND_CLOSEST(clk_get_rate(i2c->clk), busfreq * 4) - 1;
+ if (clkdiv < 0 || clkdiv > 0xffff)
+ return dev_err_probe(dev, -EINVAL, "invalid clkdiv value: %d\n",
+ clkdiv);
+
+ i2c->irq = platform_get_irq(pdev, 0);
+ if (i2c->irq < 0)
+ return dev_err_probe(dev, i2c->irq, "failed to get irq\n");
+
+ platform_set_drvdata(pdev, i2c);
+
+ pm_runtime_set_autosuspend_delay(dev, I2C_PM_TIMEOUT_MS);
+ pm_runtime_use_autosuspend(dev);
+ devm_pm_runtime_enable(dev);
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to resume device\n");
+
+ writel(FIELD_PREP(MA35_CLKDIV_MSK, clkdiv), i2c->regs + MA35_CLKDIV);
+
+ ret = devm_request_irq(dev, i2c->irq, ma35d1_i2c_irq, IRQF_SHARED,
+ dev_name(dev), i2c);
+ if (ret) {
+ dev_err_probe(dev, ret, "cannot claim IRQ %d\n", i2c->irq);
+ goto rpm_put;
+ }
+
+ ret = devm_i2c_add_adapter(dev, &i2c->adap);
+ if (ret) {
+ dev_err_probe(dev, ret, "failed to add bus to i2c core\n");
+ goto rpm_put;
+ }
+
+ pm_runtime_put_autosuspend(dev);
+
+ return 0;
+
+rpm_put:
+ pm_runtime_put_noidle(dev);
+ return ret;
+}
+
+static int ma35d1_i2c_suspend(struct device *dev)
+{
+ struct ma35d1_i2c *i2c = dev_get_drvdata(dev);
+ unsigned int val;
+
+ spin_lock_irq(&i2c->lock);
+
+ /* Prepare for wake-up from I2C events if target mode is active */
+ if (i2c->target) {
+ val = readl(i2c->regs + MA35_CTL0);
+ val |= (MA35_CTL_SI | MA35_CTL_AA);
+ writel(val, i2c->regs + MA35_CTL0);
+ ma35d1_i2c_enable_irq(i2c);
+ }
+
+ spin_unlock_irq(&i2c->lock);
+
+ /* Setup wake-up control */
+ writel(0x1, i2c->regs + MA35_WKCTL);
+
+ /* Clear pending wake-up flags */
+ val = readl(i2c->regs + MA35_WKSTS);
+ writel(val, i2c->regs + MA35_WKSTS);
+
+ enable_irq_wake(i2c->irq);
+
+ return 0;
+}
+
+static int ma35d1_i2c_resume(struct device *dev)
+{
+ struct ma35d1_i2c *i2c = dev_get_drvdata(dev);
+ unsigned int val;
+
+ /* Disable wake-up */
+ writel(0x0, i2c->regs + MA35_WKCTL);
+
+ /* Clear pending wake-up flags */
+ val = readl(i2c->regs + MA35_WKSTS);
+ writel(val, i2c->regs + MA35_WKSTS);
+
+ disable_irq_wake(i2c->irq);
+
+ return 0;
+}
+
+static int ma35d1_i2c_runtime_suspend(struct device *dev)
+{
+ struct ma35d1_i2c *i2c = dev_get_drvdata(dev);
+ unsigned int val;
+
+ /* Disable I2C controller */
+ val = readl(i2c->regs + MA35_CTL0);
+ val &= ~MA35_CTL_I2CEN;
+ writel(val, i2c->regs + MA35_CTL0);
+
+ clk_disable(i2c->clk);
+
+ return 0;
+}
+
+static int ma35d1_i2c_runtime_resume(struct device *dev)
+{
+ struct ma35d1_i2c *i2c = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret;
+
+ ret = clk_enable(i2c->clk);
+ if (ret) {
+ dev_err(dev, "failed to enable clock in resume\n");
+ return ret;
+ }
+
+ /* Enable I2C controller */
+ val = readl(i2c->regs + MA35_CTL0);
+ val |= MA35_CTL_I2CEN;
+ writel(val, i2c->regs + MA35_CTL0);
+
+ return 0;
+}
+
+static const struct dev_pm_ops ma35d1_i2c_pmops = {
+ SYSTEM_SLEEP_PM_OPS(ma35d1_i2c_suspend, ma35d1_i2c_resume)
+ RUNTIME_PM_OPS(ma35d1_i2c_runtime_suspend,
+ ma35d1_i2c_runtime_resume, NULL)
+};
+
+static const struct of_device_id ma35d1_i2c_of_match[] = {
+ { .compatible = "nuvoton,ma35d1-i2c" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ma35d1_i2c_of_match);
+
+static struct platform_driver ma35d1_i2c_driver = {
+ .probe = ma35d1_i2c_probe,
+ .driver = {
+ .name = "ma35d1-i2c",
+ .of_match_table = ma35d1_i2c_of_match,
+ .pm = pm_ptr(&ma35d1_i2c_pmops),
+ },
+};
+module_platform_driver(ma35d1_i2c_driver);
+
+MODULE_AUTHOR("Zi-Yu Chen <zychennvt@gmail.com>");
+MODULE_DESCRIPTION("MA35D1 I2C Bus Driver");
+MODULE_LICENSE("GPL");
--
2.34.1
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