v4.19.13 snapshot.
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
new file mode 100644
index 0000000..a19fbff
--- /dev/null
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -0,0 +1,954 @@
+/*
+ * Aspeed 24XX/25XX I2C Controller.
+ *
+ * Copyright (C) 2012-2017 ASPEED Technology Inc.
+ * Copyright 2017 IBM Corporation
+ * Copyright 2017 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+/* I2C Register */
+#define ASPEED_I2C_FUN_CTRL_REG 0x00
+#define ASPEED_I2C_AC_TIMING_REG1 0x04
+#define ASPEED_I2C_AC_TIMING_REG2 0x08
+#define ASPEED_I2C_INTR_CTRL_REG 0x0c
+#define ASPEED_I2C_INTR_STS_REG 0x10
+#define ASPEED_I2C_CMD_REG 0x14
+#define ASPEED_I2C_DEV_ADDR_REG 0x18
+#define ASPEED_I2C_BYTE_BUF_REG 0x20
+
+/* Global Register Definition */
+/* 0x00 : I2C Interrupt Status Register */
+/* 0x08 : I2C Interrupt Target Assignment */
+
+/* Device Register Definition */
+/* 0x00 : I2CD Function Control Register */
+#define ASPEED_I2CD_MULTI_MASTER_DIS BIT(15)
+#define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8)
+#define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7)
+#define ASPEED_I2CD_M_HIGH_SPEED_EN BIT(6)
+#define ASPEED_I2CD_SLAVE_EN BIT(1)
+#define ASPEED_I2CD_MASTER_EN BIT(0)
+
+/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
+#define ASPEED_I2CD_TIME_TBUF_MASK GENMASK(31, 28)
+#define ASPEED_I2CD_TIME_THDSTA_MASK GENMASK(27, 24)
+#define ASPEED_I2CD_TIME_TACST_MASK GENMASK(23, 20)
+#define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT 16
+#define ASPEED_I2CD_TIME_SCL_HIGH_MASK GENMASK(19, 16)
+#define ASPEED_I2CD_TIME_SCL_LOW_SHIFT 12
+#define ASPEED_I2CD_TIME_SCL_LOW_MASK GENMASK(15, 12)
+#define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK GENMASK(3, 0)
+#define ASPEED_I2CD_TIME_SCL_REG_MAX GENMASK(3, 0)
+/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
+#define ASPEED_NO_TIMEOUT_CTRL 0
+
+/* 0x0c : I2CD Interrupt Control Register &
+ * 0x10 : I2CD Interrupt Status Register
+ *
+ * These share bit definitions, so use the same values for the enable &
+ * status bits.
+ */
+#define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT BIT(14)
+#define ASPEED_I2CD_INTR_BUS_RECOVER_DONE BIT(13)
+#define ASPEED_I2CD_INTR_SLAVE_MATCH BIT(7)
+#define ASPEED_I2CD_INTR_SCL_TIMEOUT BIT(6)
+#define ASPEED_I2CD_INTR_ABNORMAL BIT(5)
+#define ASPEED_I2CD_INTR_NORMAL_STOP BIT(4)
+#define ASPEED_I2CD_INTR_ARBIT_LOSS BIT(3)
+#define ASPEED_I2CD_INTR_RX_DONE BIT(2)
+#define ASPEED_I2CD_INTR_TX_NAK BIT(1)
+#define ASPEED_I2CD_INTR_TX_ACK BIT(0)
+#define ASPEED_I2CD_INTR_ALL \
+ (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \
+ ASPEED_I2CD_INTR_BUS_RECOVER_DONE | \
+ ASPEED_I2CD_INTR_SCL_TIMEOUT | \
+ ASPEED_I2CD_INTR_ABNORMAL | \
+ ASPEED_I2CD_INTR_NORMAL_STOP | \
+ ASPEED_I2CD_INTR_ARBIT_LOSS | \
+ ASPEED_I2CD_INTR_RX_DONE | \
+ ASPEED_I2CD_INTR_TX_NAK | \
+ ASPEED_I2CD_INTR_TX_ACK)
+
+/* 0x14 : I2CD Command/Status Register */
+#define ASPEED_I2CD_SCL_LINE_STS BIT(18)
+#define ASPEED_I2CD_SDA_LINE_STS BIT(17)
+#define ASPEED_I2CD_BUS_BUSY_STS BIT(16)
+#define ASPEED_I2CD_BUS_RECOVER_CMD BIT(11)
+
+/* Command Bit */
+#define ASPEED_I2CD_M_STOP_CMD BIT(5)
+#define ASPEED_I2CD_M_S_RX_CMD_LAST BIT(4)
+#define ASPEED_I2CD_M_RX_CMD BIT(3)
+#define ASPEED_I2CD_S_TX_CMD BIT(2)
+#define ASPEED_I2CD_M_TX_CMD BIT(1)
+#define ASPEED_I2CD_M_START_CMD BIT(0)
+
+/* 0x18 : I2CD Slave Device Address Register */
+#define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0)
+
+enum aspeed_i2c_master_state {
+ ASPEED_I2C_MASTER_INACTIVE,
+ ASPEED_I2C_MASTER_START,
+ ASPEED_I2C_MASTER_TX_FIRST,
+ ASPEED_I2C_MASTER_TX,
+ ASPEED_I2C_MASTER_RX_FIRST,
+ ASPEED_I2C_MASTER_RX,
+ ASPEED_I2C_MASTER_STOP,
+};
+
+enum aspeed_i2c_slave_state {
+ ASPEED_I2C_SLAVE_STOP,
+ ASPEED_I2C_SLAVE_START,
+ ASPEED_I2C_SLAVE_READ_REQUESTED,
+ ASPEED_I2C_SLAVE_READ_PROCESSED,
+ ASPEED_I2C_SLAVE_WRITE_REQUESTED,
+ ASPEED_I2C_SLAVE_WRITE_RECEIVED,
+};
+
+struct aspeed_i2c_bus {
+ struct i2c_adapter adap;
+ struct device *dev;
+ void __iomem *base;
+ struct reset_control *rst;
+ /* Synchronizes I/O mem access to base. */
+ spinlock_t lock;
+ struct completion cmd_complete;
+ u32 (*get_clk_reg_val)(u32 divisor);
+ unsigned long parent_clk_frequency;
+ u32 bus_frequency;
+ /* Transaction state. */
+ enum aspeed_i2c_master_state master_state;
+ struct i2c_msg *msgs;
+ size_t buf_index;
+ size_t msgs_index;
+ size_t msgs_count;
+ bool send_stop;
+ int cmd_err;
+ /* Protected only by i2c_lock_bus */
+ int master_xfer_result;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ struct i2c_client *slave;
+ enum aspeed_i2c_slave_state slave_state;
+#endif /* CONFIG_I2C_SLAVE */
+};
+
+static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus);
+
+static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
+{
+ unsigned long time_left, flags;
+ int ret = 0;
+ u32 command;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ command = readl(bus->base + ASPEED_I2C_CMD_REG);
+
+ if (command & ASPEED_I2CD_SDA_LINE_STS) {
+ /* Bus is idle: no recovery needed. */
+ if (command & ASPEED_I2CD_SCL_LINE_STS)
+ goto out;
+ dev_dbg(bus->dev, "SCL hung (state %x), attempting recovery\n",
+ command);
+
+ reinit_completion(&bus->cmd_complete);
+ writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_timeout(
+ &bus->cmd_complete, bus->adap.timeout);
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (time_left == 0)
+ goto reset_out;
+ else if (bus->cmd_err)
+ goto reset_out;
+ /* Recovery failed. */
+ else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
+ ASPEED_I2CD_SCL_LINE_STS))
+ goto reset_out;
+ /* Bus error. */
+ } else {
+ dev_dbg(bus->dev, "SDA hung (state %x), attempting recovery\n",
+ command);
+
+ reinit_completion(&bus->cmd_complete);
+ /* Writes 1 to 8 SCL clock cycles until SDA is released. */
+ writel(ASPEED_I2CD_BUS_RECOVER_CMD,
+ bus->base + ASPEED_I2C_CMD_REG);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_timeout(
+ &bus->cmd_complete, bus->adap.timeout);
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (time_left == 0)
+ goto reset_out;
+ else if (bus->cmd_err)
+ goto reset_out;
+ /* Recovery failed. */
+ else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
+ ASPEED_I2CD_SDA_LINE_STS))
+ goto reset_out;
+ }
+
+out:
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ return ret;
+
+reset_out:
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ return aspeed_i2c_reset(bus);
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus)
+{
+ u32 command, irq_status, status_ack = 0;
+ struct i2c_client *slave = bus->slave;
+ bool irq_handled = true;
+ u8 value;
+
+ if (!slave) {
+ irq_handled = false;
+ goto out;
+ }
+
+ command = readl(bus->base + ASPEED_I2C_CMD_REG);
+ irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
+
+ /* Slave was requested, restart state machine. */
+ if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
+ status_ack |= ASPEED_I2CD_INTR_SLAVE_MATCH;
+ bus->slave_state = ASPEED_I2C_SLAVE_START;
+ }
+
+ /* Slave is not currently active, irq was for someone else. */
+ if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
+ irq_handled = false;
+ goto out;
+ }
+
+ dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
+ irq_status, command);
+
+ /* Slave was sent something. */
+ if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {
+ value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
+ /* Handle address frame. */
+ if (bus->slave_state == ASPEED_I2C_SLAVE_START) {
+ if (value & 0x1)
+ bus->slave_state =
+ ASPEED_I2C_SLAVE_READ_REQUESTED;
+ else
+ bus->slave_state =
+ ASPEED_I2C_SLAVE_WRITE_REQUESTED;
+ }
+ status_ack |= ASPEED_I2CD_INTR_RX_DONE;
+ }
+
+ /* Slave was asked to stop. */
+ if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
+ status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ }
+ if (irq_status & ASPEED_I2CD_INTR_TX_NAK) {
+ status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ }
+
+ switch (bus->slave_state) {
+ case ASPEED_I2C_SLAVE_READ_REQUESTED:
+ if (irq_status & ASPEED_I2CD_INTR_TX_ACK)
+ dev_err(bus->dev, "Unexpected ACK on read request.\n");
+ bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED;
+
+ i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
+ writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
+ writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
+ break;
+ case ASPEED_I2C_SLAVE_READ_PROCESSED:
+ status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+ if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK))
+ dev_err(bus->dev,
+ "Expected ACK after processed read.\n");
+ i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
+ writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
+ writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
+ break;
+ case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
+ bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+ break;
+ case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+ break;
+ case ASPEED_I2C_SLAVE_STOP:
+ i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
+ break;
+ default:
+ dev_err(bus->dev, "unhandled slave_state: %d\n",
+ bus->slave_state);
+ break;
+ }
+
+ if (status_ack != irq_status)
+ dev_err(bus->dev,
+ "irq handled != irq. expected %x, but was %x\n",
+ irq_status, status_ack);
+ writel(status_ack, bus->base + ASPEED_I2C_INTR_STS_REG);
+
+out:
+ return irq_handled;
+}
+#endif /* CONFIG_I2C_SLAVE */
+
+/* precondition: bus.lock has been acquired. */
+static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
+{
+ u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
+ struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
+ u8 slave_addr = i2c_8bit_addr_from_msg(msg);
+
+ bus->master_state = ASPEED_I2C_MASTER_START;
+ bus->buf_index = 0;
+
+ if (msg->flags & I2C_M_RD) {
+ command |= ASPEED_I2CD_M_RX_CMD;
+ /* Need to let the hardware know to NACK after RX. */
+ if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ }
+
+ writel(slave_addr, bus->base + ASPEED_I2C_BYTE_BUF_REG);
+ writel(command, bus->base + ASPEED_I2C_CMD_REG);
+}
+
+/* precondition: bus.lock has been acquired. */
+static void aspeed_i2c_do_stop(struct aspeed_i2c_bus *bus)
+{
+ bus->master_state = ASPEED_I2C_MASTER_STOP;
+ writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
+}
+
+/* precondition: bus.lock has been acquired. */
+static void aspeed_i2c_next_msg_or_stop(struct aspeed_i2c_bus *bus)
+{
+ if (bus->msgs_index + 1 < bus->msgs_count) {
+ bus->msgs_index++;
+ aspeed_i2c_do_start(bus);
+ } else {
+ aspeed_i2c_do_stop(bus);
+ }
+}
+
+static int aspeed_i2c_is_irq_error(u32 irq_status)
+{
+ if (irq_status & ASPEED_I2CD_INTR_ARBIT_LOSS)
+ return -EAGAIN;
+ if (irq_status & (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |
+ ASPEED_I2CD_INTR_SCL_TIMEOUT))
+ return -EBUSY;
+ if (irq_status & (ASPEED_I2CD_INTR_ABNORMAL))
+ return -EPROTO;
+
+ return 0;
+}
+
+static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
+{
+ u32 irq_status, status_ack = 0, command = 0;
+ struct i2c_msg *msg;
+ u8 recv_byte;
+ int ret;
+
+ irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
+ /* Ack all interrupt bits. */
+ writel(irq_status, bus->base + ASPEED_I2C_INTR_STS_REG);
+
+ if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ status_ack |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
+ goto out_complete;
+ }
+
+ /*
+ * We encountered an interrupt that reports an error: the hardware
+ * should clear the command queue effectively taking us back to the
+ * INACTIVE state.
+ */
+ ret = aspeed_i2c_is_irq_error(irq_status);
+ if (ret < 0) {
+ dev_dbg(bus->dev, "received error interrupt: 0x%08x\n",
+ irq_status);
+ bus->cmd_err = ret;
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ goto out_complete;
+ }
+
+ /* We are in an invalid state; reset bus to a known state. */
+ if (!bus->msgs) {
+ dev_err(bus->dev, "bus in unknown state\n");
+ bus->cmd_err = -EIO;
+ if (bus->master_state != ASPEED_I2C_MASTER_STOP)
+ aspeed_i2c_do_stop(bus);
+ goto out_no_complete;
+ }
+ msg = &bus->msgs[bus->msgs_index];
+
+ /*
+ * START is a special case because we still have to handle a subsequent
+ * TX or RX immediately after we handle it, so we handle it here and
+ * then update the state and handle the new state below.
+ */
+ if (bus->master_state == ASPEED_I2C_MASTER_START) {
+ if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
+ pr_devel("no slave present at %02x\n", msg->addr);
+ status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+ bus->cmd_err = -ENXIO;
+ aspeed_i2c_do_stop(bus);
+ goto out_no_complete;
+ }
+ status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+ if (msg->len == 0) { /* SMBUS_QUICK */
+ aspeed_i2c_do_stop(bus);
+ goto out_no_complete;
+ }
+ if (msg->flags & I2C_M_RD)
+ bus->master_state = ASPEED_I2C_MASTER_RX_FIRST;
+ else
+ bus->master_state = ASPEED_I2C_MASTER_TX_FIRST;
+ }
+
+ switch (bus->master_state) {
+ case ASPEED_I2C_MASTER_TX:
+ if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
+ dev_dbg(bus->dev, "slave NACKed TX\n");
+ status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+ goto error_and_stop;
+ } else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
+ dev_err(bus->dev, "slave failed to ACK TX\n");
+ goto error_and_stop;
+ }
+ status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+ /* fallthrough intended */
+ case ASPEED_I2C_MASTER_TX_FIRST:
+ if (bus->buf_index < msg->len) {
+ bus->master_state = ASPEED_I2C_MASTER_TX;
+ writel(msg->buf[bus->buf_index++],
+ bus->base + ASPEED_I2C_BYTE_BUF_REG);
+ writel(ASPEED_I2CD_M_TX_CMD,
+ bus->base + ASPEED_I2C_CMD_REG);
+ } else {
+ aspeed_i2c_next_msg_or_stop(bus);
+ }
+ goto out_no_complete;
+ case ASPEED_I2C_MASTER_RX_FIRST:
+ /* RX may not have completed yet (only address cycle) */
+ if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE))
+ goto out_no_complete;
+ /* fallthrough intended */
+ case ASPEED_I2C_MASTER_RX:
+ if (unlikely(!(irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
+ dev_err(bus->dev, "master failed to RX\n");
+ goto error_and_stop;
+ }
+ status_ack |= ASPEED_I2CD_INTR_RX_DONE;
+
+ recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
+ msg->buf[bus->buf_index++] = recv_byte;
+
+ if (msg->flags & I2C_M_RECV_LEN) {
+ if (unlikely(recv_byte > I2C_SMBUS_BLOCK_MAX)) {
+ bus->cmd_err = -EPROTO;
+ aspeed_i2c_do_stop(bus);
+ goto out_no_complete;
+ }
+ msg->len = recv_byte +
+ ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
+ msg->flags &= ~I2C_M_RECV_LEN;
+ }
+
+ if (bus->buf_index < msg->len) {
+ bus->master_state = ASPEED_I2C_MASTER_RX;
+ command = ASPEED_I2CD_M_RX_CMD;
+ if (bus->buf_index + 1 == msg->len)
+ command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
+ writel(command, bus->base + ASPEED_I2C_CMD_REG);
+ } else {
+ aspeed_i2c_next_msg_or_stop(bus);
+ }
+ goto out_no_complete;
+ case ASPEED_I2C_MASTER_STOP:
+ if (unlikely(!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP))) {
+ dev_err(bus->dev, "master failed to STOP\n");
+ bus->cmd_err = -EIO;
+ /* Do not STOP as we have already tried. */
+ } else {
+ status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
+ }
+
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ goto out_complete;
+ case ASPEED_I2C_MASTER_INACTIVE:
+ dev_err(bus->dev,
+ "master received interrupt 0x%08x, but is inactive\n",
+ irq_status);
+ bus->cmd_err = -EIO;
+ /* Do not STOP as we should be inactive. */
+ goto out_complete;
+ default:
+ WARN(1, "unknown master state\n");
+ bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+ bus->cmd_err = -EINVAL;
+ goto out_complete;
+ }
+error_and_stop:
+ bus->cmd_err = -EIO;
+ aspeed_i2c_do_stop(bus);
+ goto out_no_complete;
+out_complete:
+ bus->msgs = NULL;
+ if (bus->cmd_err)
+ bus->master_xfer_result = bus->cmd_err;
+ else
+ bus->master_xfer_result = bus->msgs_index + 1;
+ complete(&bus->cmd_complete);
+out_no_complete:
+ if (irq_status != status_ack)
+ dev_err(bus->dev,
+ "irq handled != irq. expected 0x%08x, but was 0x%08x\n",
+ irq_status, status_ack);
+ return !!irq_status;
+}
+
+static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
+{
+ struct aspeed_i2c_bus *bus = dev_id;
+ bool ret;
+
+ spin_lock(&bus->lock);
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (IS_ENABLED(CONFIG_I2C_SLAVE) && aspeed_i2c_slave_irq(bus)) {
+ dev_dbg(bus->dev, "irq handled by slave.\n");
+ ret = true;
+ goto out;
+ }
+#endif /* CONFIG_I2C_SLAVE */
+
+ ret = aspeed_i2c_master_irq(bus);
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+out:
+#endif
+ spin_unlock(&bus->lock);
+ return ret ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);
+ unsigned long time_left, flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ bus->cmd_err = 0;
+
+ /* If bus is busy, attempt recovery. We assume a single master
+ * environment.
+ */
+ if (readl(bus->base + ASPEED_I2C_CMD_REG) & ASPEED_I2CD_BUS_BUSY_STS) {
+ spin_unlock_irqrestore(&bus->lock, flags);
+ ret = aspeed_i2c_recover_bus(bus);
+ if (ret)
+ return ret;
+ spin_lock_irqsave(&bus->lock, flags);
+ }
+
+ bus->cmd_err = 0;
+ bus->msgs = msgs;
+ bus->msgs_index = 0;
+ bus->msgs_count = num;
+
+ reinit_completion(&bus->cmd_complete);
+ aspeed_i2c_do_start(bus);
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ time_left = wait_for_completion_timeout(&bus->cmd_complete,
+ bus->adap.timeout);
+
+ if (time_left == 0)
+ return -ETIMEDOUT;
+ else
+ return bus->master_xfer_result;
+}
+
+static u32 aspeed_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+/* precondition: bus.lock has been acquired. */
+static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr)
+{
+ u32 addr_reg_val, func_ctrl_reg_val;
+
+ /* Set slave addr. */
+ addr_reg_val = readl(bus->base + ASPEED_I2C_DEV_ADDR_REG);
+ addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR_MASK;
+ addr_reg_val |= slave_addr & ASPEED_I2CD_DEV_ADDR_MASK;
+ writel(addr_reg_val, bus->base + ASPEED_I2C_DEV_ADDR_REG);
+
+ /* Turn on slave mode. */
+ func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
+ func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
+ writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+}
+
+static int aspeed_i2c_reg_slave(struct i2c_client *client)
+{
+ struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (bus->slave) {
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return -EINVAL;
+ }
+
+ __aspeed_i2c_reg_slave(bus, client->addr);
+
+ bus->slave = client;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ return 0;
+}
+
+static int aspeed_i2c_unreg_slave(struct i2c_client *client)
+{
+ struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
+ u32 func_ctrl_reg_val;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bus->lock, flags);
+ if (!bus->slave) {
+ spin_unlock_irqrestore(&bus->lock, flags);
+ return -EINVAL;
+ }
+
+ /* Turn off slave mode. */
+ func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
+ func_ctrl_reg_val &= ~ASPEED_I2CD_SLAVE_EN;
+ writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+
+ bus->slave = NULL;
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ return 0;
+}
+#endif /* CONFIG_I2C_SLAVE */
+
+static const struct i2c_algorithm aspeed_i2c_algo = {
+ .master_xfer = aspeed_i2c_master_xfer,
+ .functionality = aspeed_i2c_functionality,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ .reg_slave = aspeed_i2c_reg_slave,
+ .unreg_slave = aspeed_i2c_unreg_slave,
+#endif /* CONFIG_I2C_SLAVE */
+};
+
+static u32 aspeed_i2c_get_clk_reg_val(u32 clk_high_low_max, u32 divisor)
+{
+ u32 base_clk, clk_high, clk_low, tmp;
+
+ /*
+ * The actual clock frequency of SCL is:
+ * SCL_freq = APB_freq / (base_freq * (SCL_high + SCL_low))
+ * = APB_freq / divisor
+ * where base_freq is a programmable clock divider; its value is
+ * base_freq = 1 << base_clk
+ * SCL_high is the number of base_freq clock cycles that SCL stays high
+ * and SCL_low is the number of base_freq clock cycles that SCL stays
+ * low for a period of SCL.
+ * The actual register has a minimum SCL_high and SCL_low minimum of 1;
+ * thus, they start counting at zero. So
+ * SCL_high = clk_high + 1
+ * SCL_low = clk_low + 1
+ * Thus,
+ * SCL_freq = APB_freq /
+ * ((1 << base_clk) * (clk_high + 1 + clk_low + 1))
+ * The documentation recommends clk_high >= clk_high_max / 2 and
+ * clk_low >= clk_low_max / 2 - 1 when possible; this last constraint
+ * gives us the following solution:
+ */
+ base_clk = divisor > clk_high_low_max ?
+ ilog2((divisor - 1) / clk_high_low_max) + 1 : 0;
+ tmp = (divisor + (1 << base_clk) - 1) >> base_clk;
+ clk_low = tmp / 2;
+ clk_high = tmp - clk_low;
+
+ if (clk_high)
+ clk_high--;
+
+ if (clk_low)
+ clk_low--;
+
+
+ return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
+ & ASPEED_I2CD_TIME_SCL_HIGH_MASK)
+ | ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT)
+ & ASPEED_I2CD_TIME_SCL_LOW_MASK)
+ | (base_clk & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
+}
+
+static u32 aspeed_i2c_24xx_get_clk_reg_val(u32 divisor)
+{
+ /*
+ * clk_high and clk_low are each 3 bits wide, so each can hold a max
+ * value of 8 giving a clk_high_low_max of 16.
+ */
+ return aspeed_i2c_get_clk_reg_val(16, divisor);
+}
+
+static u32 aspeed_i2c_25xx_get_clk_reg_val(u32 divisor)
+{
+ /*
+ * clk_high and clk_low are each 4 bits wide, so each can hold a max
+ * value of 16 giving a clk_high_low_max of 32.
+ */
+ return aspeed_i2c_get_clk_reg_val(32, divisor);
+}
+
+/* precondition: bus.lock has been acquired. */
+static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus)
+{
+ u32 divisor, clk_reg_val;
+
+ divisor = DIV_ROUND_UP(bus->parent_clk_frequency, bus->bus_frequency);
+ clk_reg_val = readl(bus->base + ASPEED_I2C_AC_TIMING_REG1);
+ clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK |
+ ASPEED_I2CD_TIME_THDSTA_MASK |
+ ASPEED_I2CD_TIME_TACST_MASK);
+ clk_reg_val |= bus->get_clk_reg_val(divisor);
+ writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1);
+ writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2);
+
+ return 0;
+}
+
+/* precondition: bus.lock has been acquired. */
+static int aspeed_i2c_init(struct aspeed_i2c_bus *bus,
+ struct platform_device *pdev)
+{
+ u32 fun_ctrl_reg = ASPEED_I2CD_MASTER_EN;
+ int ret;
+
+ /* Disable everything. */
+ writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+
+ ret = aspeed_i2c_init_clk(bus);
+ if (ret < 0)
+ return ret;
+
+ if (!of_property_read_bool(pdev->dev.of_node, "multi-master"))
+ fun_ctrl_reg |= ASPEED_I2CD_MULTI_MASTER_DIS;
+
+ /* Enable Master Mode */
+ writel(readl(bus->base + ASPEED_I2C_FUN_CTRL_REG) | fun_ctrl_reg,
+ bus->base + ASPEED_I2C_FUN_CTRL_REG);
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ /* If slave has already been registered, re-enable it. */
+ if (bus->slave)
+ __aspeed_i2c_reg_slave(bus, bus->slave->addr);
+#endif /* CONFIG_I2C_SLAVE */
+
+ /* Set interrupt generation of I2C controller */
+ writel(ASPEED_I2CD_INTR_ALL, bus->base + ASPEED_I2C_INTR_CTRL_REG);
+
+ return 0;
+}
+
+static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus)
+{
+ struct platform_device *pdev = to_platform_device(bus->dev);
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&bus->lock, flags);
+
+ /* Disable and ack all interrupts. */
+ writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
+ writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
+
+ ret = aspeed_i2c_init(bus, pdev);
+
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ return ret;
+}
+
+static const struct of_device_id aspeed_i2c_bus_of_table[] = {
+ {
+ .compatible = "aspeed,ast2400-i2c-bus",
+ .data = aspeed_i2c_24xx_get_clk_reg_val,
+ },
+ {
+ .compatible = "aspeed,ast2500-i2c-bus",
+ .data = aspeed_i2c_25xx_get_clk_reg_val,
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table);
+
+static int aspeed_i2c_probe_bus(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ struct aspeed_i2c_bus *bus;
+ struct clk *parent_clk;
+ struct resource *res;
+ int irq, ret;
+
+ bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+ if (!bus)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ bus->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(bus->base))
+ return PTR_ERR(bus->base);
+
+ parent_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(parent_clk))
+ return PTR_ERR(parent_clk);
+ bus->parent_clk_frequency = clk_get_rate(parent_clk);
+ /* We just need the clock rate, we don't actually use the clk object. */
+ devm_clk_put(&pdev->dev, parent_clk);
+
+ bus->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
+ if (IS_ERR(bus->rst)) {
+ dev_err(&pdev->dev,
+ "missing or invalid reset controller device tree entry\n");
+ return PTR_ERR(bus->rst);
+ }
+ reset_control_deassert(bus->rst);
+
+ ret = of_property_read_u32(pdev->dev.of_node,
+ "bus-frequency", &bus->bus_frequency);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Could not read bus-frequency property\n");
+ bus->bus_frequency = 100000;
+ }
+
+ match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node);
+ if (!match)
+ bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val;
+ else
+ bus->get_clk_reg_val = (u32 (*)(u32))match->data;
+
+ /* Initialize the I2C adapter */
+ spin_lock_init(&bus->lock);
+ init_completion(&bus->cmd_complete);
+ bus->adap.owner = THIS_MODULE;
+ bus->adap.retries = 0;
+ bus->adap.timeout = 5 * HZ;
+ bus->adap.algo = &aspeed_i2c_algo;
+ bus->adap.dev.parent = &pdev->dev;
+ bus->adap.dev.of_node = pdev->dev.of_node;
+ strlcpy(bus->adap.name, pdev->name, sizeof(bus->adap.name));
+ i2c_set_adapdata(&bus->adap, bus);
+
+ bus->dev = &pdev->dev;
+
+ /* Clean up any left over interrupt state. */
+ writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
+ writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
+ /*
+ * bus.lock does not need to be held because the interrupt handler has
+ * not been enabled yet.
+ */
+ ret = aspeed_i2c_init(bus, pdev);
+ if (ret < 0)
+ return ret;
+
+ irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+ ret = devm_request_irq(&pdev->dev, irq, aspeed_i2c_bus_irq,
+ 0, dev_name(&pdev->dev), bus);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_add_adapter(&bus->adap);
+ if (ret < 0)
+ return ret;
+
+ platform_set_drvdata(pdev, bus);
+
+ dev_info(bus->dev, "i2c bus %d registered, irq %d\n",
+ bus->adap.nr, irq);
+
+ return 0;
+}
+
+static int aspeed_i2c_remove_bus(struct platform_device *pdev)
+{
+ struct aspeed_i2c_bus *bus = platform_get_drvdata(pdev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bus->lock, flags);
+
+ /* Disable everything. */
+ writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+ writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
+
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ reset_control_assert(bus->rst);
+
+ i2c_del_adapter(&bus->adap);
+
+ return 0;
+}
+
+static struct platform_driver aspeed_i2c_bus_driver = {
+ .probe = aspeed_i2c_probe_bus,
+ .remove = aspeed_i2c_remove_bus,
+ .driver = {
+ .name = "aspeed-i2c-bus",
+ .of_match_table = aspeed_i2c_bus_of_table,
+ },
+};
+module_platform_driver(aspeed_i2c_bus_driver);
+
+MODULE_AUTHOR("Brendan Higgins <brendanhiggins@google.com>");
+MODULE_DESCRIPTION("Aspeed I2C Bus Driver");
+MODULE_LICENSE("GPL v2");