Google Git
Sign in
android-kvm / linux / 54bbee190d42166209185d89070c58a343bf514b / . / drivers / i2c / busses / i2c-aspeed.c
blob: cc5a26637fd540d3781d11ab133a7e5908525855 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Aspeed 24XX/25XX I2C Controller.
*
* Copyright (C) 2012-2017 ASPEED Technology Inc.
* Copyright 2017 IBM Corporation
* Copyright 2017 Google, Inc.
*/
#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/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_RECV_MASK 0xf000ffff
#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_MASTER_ERRORS \
(ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \
ASPEED_I2CD_INTR_SCL_TIMEOUT | \
ASPEED_I2CD_INTR_ABNORMAL | \
ASPEED_I2CD_INTR_ARBIT_LOSS)
#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)
#define ASPEED_I2CD_MASTER_CMDS_MASK \
(ASPEED_I2CD_M_STOP_CMD | \
ASPEED_I2CD_M_S_RX_CMD_LAST | \
ASPEED_I2CD_M_RX_CMD | \
ASPEED_I2CD_M_TX_CMD | \
ASPEED_I2CD_M_START_CMD)
/* 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_PENDING,
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_INACTIVE,
ASPEED_I2C_SLAVE_START,
ASPEED_I2C_SLAVE_READ_REQUESTED,
ASPEED_I2C_SLAVE_READ_PROCESSED,
ASPEED_I2C_SLAVE_WRITE_REQUESTED,
ASPEED_I2C_SLAVE_WRITE_RECEIVED,
ASPEED_I2C_SLAVE_STOP,
};
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)(struct device *dev,
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;
/* Multi-master */
bool multi_master;
#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);
/* 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);
}
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);
aspeed_i2c_do_stop(bus);
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 u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
{
u32 command, irq_handled = 0;
struct i2c_client *slave = bus->slave;
u8 value;
int ret;
if (!slave)
return 0;
/*
* Handle stop conditions early, prior to SLAVE_MATCH. Some masters may drive
* transfers with low enough latency between the nak/stop phase of the current
* command and the start/address phase of the following command that the
* interrupts are coalesced by the time we process them.
*/
if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
/* Propagate any stop conditions to the slave implementation. */
if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
}
/*
* Now that we've dealt with any potentially coalesced stop conditions,
* address any start conditions.
*/
if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
bus->slave_state = ASPEED_I2C_SLAVE_START;
}
/*
* If the slave has been stopped and not started then slave interrupt
* handling is complete.
*/
if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
return irq_handled;
command = readl(bus->base + ASPEED_I2C_CMD_REG);
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;
}
irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
}
switch (bus->slave_state) {
case ASPEED_I2C_SLAVE_READ_REQUESTED:
if (unlikely(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:
if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
dev_err(bus->dev,
"Expected ACK after processed read.\n");
break;
}
irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
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;
ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
/*
* Slave ACK's on this address phase already but as the backend driver
* returns an errno, the bus driver should nack the next incoming byte.
*/
if (ret < 0)
writel(ASPEED_I2CD_M_S_RX_CMD_LAST, bus->base + ASPEED_I2C_CMD_REG);
break;
case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
break;
case ASPEED_I2C_SLAVE_STOP:
/* Stop event handling is done early. Unreachable. */
break;
case ASPEED_I2C_SLAVE_START:
/* Slave was just started. Waiting for the next event. */;
break;
default:
dev_err(bus->dev, "unknown slave_state: %d\n",
bus->slave_state);
bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
break;
}
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);
#if IS_ENABLED(CONFIG_I2C_SLAVE)
/*
* If it's requested in the middle of a slave session, set the master
* state to 'pending' then H/W will continue handling this master
* command when the bus comes back to the idle state.
*/
if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) {
bus->master_state = ASPEED_I2C_MASTER_PENDING;
return;
}
#endif /* CONFIG_I2C_SLAVE */
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_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 u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
{
u32 irq_handled = 0, command = 0;
struct i2c_msg *msg;
u8 recv_byte;
int ret;
if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
irq_handled |= 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) {
dev_dbg(bus->dev, "received error interrupt: 0x%08x\n",
irq_status);
irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
irq_handled = irq_status;
bus->cmd_err = ret;
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
goto out_complete;
}
}
/* Master is not currently active, irq was for someone else. */
if (bus->master_state == ASPEED_I2C_MASTER_INACTIVE ||
bus->master_state == ASPEED_I2C_MASTER_PENDING)
goto out_no_complete;
/* We are in an invalid state; reset bus to a known state. */
if (!bus->msgs) {
dev_err(bus->dev, "bus in unknown state. irq_status: 0x%x\n",
irq_status);
bus->cmd_err = -EIO;
if (bus->master_state != ASPEED_I2C_MASTER_STOP &&
bus->master_state != ASPEED_I2C_MASTER_INACTIVE)
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 IS_ENABLED(CONFIG_I2C_SLAVE)
/*
* If a peer master starts a xfer immediately after it queues a
* master command, clear the queued master command and change
* its state to 'pending'. To simplify handling of pending
* cases, it uses S/W solution instead of H/W command queue
* handling.
*/
if (unlikely(irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH)) {
writel(readl(bus->base + ASPEED_I2C_CMD_REG) &
~ASPEED_I2CD_MASTER_CMDS_MASK,
bus->base + ASPEED_I2C_CMD_REG);
bus->master_state = ASPEED_I2C_MASTER_PENDING;
dev_dbg(bus->dev,
"master goes pending due to a slave start\n");
goto out_no_complete;
}
#endif /* CONFIG_I2C_SLAVE */
if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_NAK))) {
bus->cmd_err = -ENXIO;
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
goto out_complete;
}
pr_devel("no slave present at %02x\n", msg->addr);
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
bus->cmd_err = -ENXIO;
aspeed_i2c_do_stop(bus);
goto out_no_complete;
}
irq_handled |= 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");
irq_handled |= 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;
}
irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
fallthrough;
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;
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;
}
irq_handled |= 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. irq_status:0x%x\n",
irq_status);
bus->cmd_err = -EIO;
/* Do not STOP as we have already tried. */
} else {
irq_handled |= 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:
return irq_handled;
}
static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
{
struct aspeed_i2c_bus *bus = dev_id;
u32 irq_received, irq_remaining, irq_handled;
spin_lock(&bus->lock);
irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
/* Ack all interrupts except for Rx done */
writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
bus->base + ASPEED_I2C_INTR_STS_REG);
readl(bus->base + ASPEED_I2C_INTR_STS_REG);
irq_received &= ASPEED_I2CD_INTR_RECV_MASK;
irq_remaining = irq_received;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
/*
* In most cases, interrupt bits will be set one by one, although
* multiple interrupt bits could be set at the same time. It's also
* possible that master interrupt bits could be set along with slave
* interrupt bits. Each case needs to be handled using corresponding
* handlers depending on the current state.
*/
if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE &&
bus->master_state != ASPEED_I2C_MASTER_PENDING) {
irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
irq_remaining &= ~irq_handled;
if (irq_remaining)
irq_handled |= aspeed_i2c_slave_irq(bus, irq_remaining);
} else {
irq_handled = aspeed_i2c_slave_irq(bus, irq_remaining);
irq_remaining &= ~irq_handled;
if (irq_remaining)
irq_handled |= aspeed_i2c_master_irq(bus,
irq_remaining);
}
/*
* Start a pending master command at here if a slave operation is
* completed.
*/
if (bus->master_state == ASPEED_I2C_MASTER_PENDING &&
bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
aspeed_i2c_do_start(bus);
#else
irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
#endif /* CONFIG_I2C_SLAVE */
irq_remaining &= ~irq_handled;
if (irq_remaining)
dev_err(bus->dev,
"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
irq_received, irq_handled);
/* Ack Rx done */
if (irq_received & ASPEED_I2CD_INTR_RX_DONE) {
writel(ASPEED_I2CD_INTR_RX_DONE,
bus->base + ASPEED_I2C_INTR_STS_REG);
readl(bus->base + ASPEED_I2C_INTR_STS_REG);
}
spin_unlock(&bus->lock);
return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
}
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;
spin_lock_irqsave(&bus->lock, flags);
bus->cmd_err = 0;
/* If bus is busy in a single master environment, attempt recovery. */
if (!bus->multi_master &&
(readl(bus->base + ASPEED_I2C_CMD_REG) &
ASPEED_I2CD_BUS_BUSY_STS)) {
int ret;
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) {
/*
* In a multi-master setup, if a timeout occurs, attempt
* recovery. But if the bus is idle, we still need to reset the
* i2c controller to clear the remaining interrupts.
*/
if (bus->multi_master &&
(readl(bus->base + ASPEED_I2C_CMD_REG) &
ASPEED_I2CD_BUS_BUSY_STS))
aspeed_i2c_recover_bus(bus);
else
aspeed_i2c_reset(bus);
/*
* If timed out and the state is still pending, drop the pending
* master command.
*/
spin_lock_irqsave(&bus->lock, flags);
if (bus->master_state == ASPEED_I2C_MASTER_PENDING)
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
spin_unlock_irqrestore(&bus->lock, flags);
return -ETIMEDOUT;
}
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. Reserved bits can all safely be written with zeros
* on all of ast2[456]00, so zero everything else to ensure we only
* enable a single slave address (ast2500 has two, ast2600 has three,
* the enable bits for which are also in this register) so that we don't
* end up with additional phantom devices responding on the bus.
*/
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);
bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
}
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;
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(struct device *dev,
u32 clk_high_low_mask,
u32 divisor)
{
u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp;
/*
* SCL_high and SCL_low represent a value 1 greater than what is stored
* since a zero divider is meaningless. Thus, the max value each can
* store is every bit set + 1. Since SCL_high and SCL_low are added
* together (see below), the max value of both is the max value of one
* them times two.
*/
clk_high_low_max = (clk_high_low_mask + 1) * 2;
/*
* 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_divisor
* 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_divisor) * (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 = divisor > clk_high_low_max ?
ilog2((divisor - 1) / clk_high_low_max) + 1 : 0;
if (base_clk_divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) {
base_clk_divisor = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK;
clk_low = clk_high_low_mask;
clk_high = clk_high_low_mask;
dev_err(dev,
"clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n",
divisor, (1 << base_clk_divisor) * clk_high_low_max);
} else {
tmp = (divisor + (1 << base_clk_divisor) - 1)
>> base_clk_divisor;
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_divisor
& ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
}
static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, 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(dev, GENMASK(2, 0), divisor);
}
static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, 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(dev, GENMASK(3, 0), 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(bus->dev, 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"))
bus->multi_master = true;
else
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,
},
{
.compatible = "aspeed,ast2600-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;
int irq, ret;
bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
if (!bus)
return -ENOMEM;
bus->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
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 = I2C_MAX_STANDARD_MODE_FREQ;
}
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 (*)(struct device *, 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.algo = &aspeed_i2c_algo;
bus->adap.dev.parent = &pdev->dev;
bus->adap.dev.of_node = pdev->dev.of_node;
strscpy(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 void 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);
}
static struct platform_driver aspeed_i2c_bus_driver = {
.probe = aspeed_i2c_probe_bus,
.remove_new = 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");