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linux/drivers/i2c/busses/i2c-aspeed.c
Eddie James 1a1d6db23d i2c: aspeed: Mask IRQ status to relevant bits 
Mask the IRQ status to only the bits that the driver checks. This
prevents excessive driver warnings when operating in slave mode
when additional bits are set that the driver doesn't handle.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-09-14 08:55:44 +02:00

1090 lines
32 KiB
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// 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/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_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);
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 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;
if (!slave)
return 0;
command = readl(bus->base + ASPEED_I2C_CMD_REG);
/* Slave was requested, restart state machine. */
if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
irq_handled |= 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_INACTIVE)
return irq_handled;
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;
}
/* Slave was asked to stop. */
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;
}
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;
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);
bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
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_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 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) {
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) {
/*
* If timed out and bus is still busy in a multi master
* environment, attempt recovery at here.
*/
if (bus->multi_master &&
(readl(bus->base + ASPEED_I2C_CMD_REG) &
ASPEED_I2CD_BUS_BUSY_STS))
aspeed_i2c_recover_bus(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. */
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_INACTIVE;
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;
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 = 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;
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");
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