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linux/drivers/i2c/busses/i2c-designware-core.c

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/*
* Synopsys DesignWare I2C adapter driver (master only).
*
* Based on the TI DAVINCI I2C adapter driver.
*
* Copyright (C) 2006 Texas Instruments.
* Copyright (C) 2007 MontaVista Software Inc.
* Copyright (C) 2009 Provigent Ltd.
*
* ----------------------------------------------------------------------------
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* ----------------------------------------------------------------------------
*
*/
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/pm_runtime.h>
#include <linux/delay.h>
#include <linux/module.h>
#include "i2c-designware-core.h"
/*
* Registers offset
*/
#define DW_IC_CON 0x0
#define DW_IC_TAR 0x4
#define DW_IC_DATA_CMD 0x10
#define DW_IC_SS_SCL_HCNT 0x14
#define DW_IC_SS_SCL_LCNT 0x18
#define DW_IC_FS_SCL_HCNT 0x1c
#define DW_IC_FS_SCL_LCNT 0x20
#define DW_IC_INTR_STAT 0x2c
#define DW_IC_INTR_MASK 0x30
#define DW_IC_RAW_INTR_STAT 0x34
#define DW_IC_RX_TL 0x38
#define DW_IC_TX_TL 0x3c
#define DW_IC_CLR_INTR 0x40
#define DW_IC_CLR_RX_UNDER 0x44
#define DW_IC_CLR_RX_OVER 0x48
#define DW_IC_CLR_TX_OVER 0x4c
#define DW_IC_CLR_RD_REQ 0x50
#define DW_IC_CLR_TX_ABRT 0x54
#define DW_IC_CLR_RX_DONE 0x58
#define DW_IC_CLR_ACTIVITY 0x5c
#define DW_IC_CLR_STOP_DET 0x60
#define DW_IC_CLR_START_DET 0x64
#define DW_IC_CLR_GEN_CALL 0x68
#define DW_IC_ENABLE 0x6c
#define DW_IC_STATUS 0x70
#define DW_IC_TXFLR 0x74
#define DW_IC_RXFLR 0x78
#define DW_IC_SDA_HOLD 0x7c
#define DW_IC_TX_ABRT_SOURCE 0x80
#define DW_IC_ENABLE_STATUS 0x9c
#define DW_IC_COMP_PARAM_1 0xf4
#define DW_IC_COMP_VERSION 0xf8
#define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A
#define DW_IC_COMP_TYPE 0xfc
#define DW_IC_COMP_TYPE_VALUE 0x44570140
#define DW_IC_INTR_RX_UNDER 0x001
#define DW_IC_INTR_RX_OVER 0x002
#define DW_IC_INTR_RX_FULL 0x004
#define DW_IC_INTR_TX_OVER 0x008
#define DW_IC_INTR_TX_EMPTY 0x010
#define DW_IC_INTR_RD_REQ 0x020
#define DW_IC_INTR_TX_ABRT 0x040
#define DW_IC_INTR_RX_DONE 0x080
#define DW_IC_INTR_ACTIVITY 0x100
#define DW_IC_INTR_STOP_DET 0x200
#define DW_IC_INTR_START_DET 0x400
#define DW_IC_INTR_GEN_CALL 0x800
#define DW_IC_INTR_DEFAULT_MASK (DW_IC_INTR_RX_FULL | \
DW_IC_INTR_TX_EMPTY | \
DW_IC_INTR_TX_ABRT | \
DW_IC_INTR_STOP_DET)
#define DW_IC_STATUS_ACTIVITY 0x1
#define DW_IC_ERR_TX_ABRT 0x1
#define DW_IC_TAR_10BITADDR_MASTER BIT(12)
/*
* status codes
*/
#define STATUS_IDLE 0x0
#define STATUS_WRITE_IN_PROGRESS 0x1
#define STATUS_READ_IN_PROGRESS 0x2
#define TIMEOUT 20 /* ms */
/*
* hardware abort codes from the DW_IC_TX_ABRT_SOURCE register
*
* only expected abort codes are listed here
* refer to the datasheet for the full list
*/
#define ABRT_7B_ADDR_NOACK 0
#define ABRT_10ADDR1_NOACK 1
#define ABRT_10ADDR2_NOACK 2
#define ABRT_TXDATA_NOACK 3
#define ABRT_GCALL_NOACK 4
#define ABRT_GCALL_READ 5
#define ABRT_SBYTE_ACKDET 7
#define ABRT_SBYTE_NORSTRT 9
#define ABRT_10B_RD_NORSTRT 10
#define ABRT_MASTER_DIS 11
#define ARB_LOST 12
#define DW_IC_TX_ABRT_7B_ADDR_NOACK (1UL << ABRT_7B_ADDR_NOACK)
#define DW_IC_TX_ABRT_10ADDR1_NOACK (1UL << ABRT_10ADDR1_NOACK)
#define DW_IC_TX_ABRT_10ADDR2_NOACK (1UL << ABRT_10ADDR2_NOACK)
#define DW_IC_TX_ABRT_TXDATA_NOACK (1UL << ABRT_TXDATA_NOACK)
#define DW_IC_TX_ABRT_GCALL_NOACK (1UL << ABRT_GCALL_NOACK)
#define DW_IC_TX_ABRT_GCALL_READ (1UL << ABRT_GCALL_READ)
#define DW_IC_TX_ABRT_SBYTE_ACKDET (1UL << ABRT_SBYTE_ACKDET)
#define DW_IC_TX_ABRT_SBYTE_NORSTRT (1UL << ABRT_SBYTE_NORSTRT)
#define DW_IC_TX_ABRT_10B_RD_NORSTRT (1UL << ABRT_10B_RD_NORSTRT)
#define DW_IC_TX_ABRT_MASTER_DIS (1UL << ABRT_MASTER_DIS)
#define DW_IC_TX_ARB_LOST (1UL << ARB_LOST)
#define DW_IC_TX_ABRT_NOACK (DW_IC_TX_ABRT_7B_ADDR_NOACK | \
DW_IC_TX_ABRT_10ADDR1_NOACK | \
DW_IC_TX_ABRT_10ADDR2_NOACK | \
DW_IC_TX_ABRT_TXDATA_NOACK | \
DW_IC_TX_ABRT_GCALL_NOACK)
static char *abort_sources[] = {
[ABRT_7B_ADDR_NOACK] =
"slave address not acknowledged (7bit mode)",
[ABRT_10ADDR1_NOACK] =
"first address byte not acknowledged (10bit mode)",
[ABRT_10ADDR2_NOACK] =
"second address byte not acknowledged (10bit mode)",
[ABRT_TXDATA_NOACK] =
"data not acknowledged",
[ABRT_GCALL_NOACK] =
"no acknowledgement for a general call",
[ABRT_GCALL_READ] =
"read after general call",
[ABRT_SBYTE_ACKDET] =
"start byte acknowledged",
[ABRT_SBYTE_NORSTRT] =
"trying to send start byte when restart is disabled",
[ABRT_10B_RD_NORSTRT] =
"trying to read when restart is disabled (10bit mode)",
[ABRT_MASTER_DIS] =
"trying to use disabled adapter",
[ARB_LOST] =
"lost arbitration",
};
u32 dw_readl(struct dw_i2c_dev *dev, int offset)
{
u32 value;
if (dev->accessor_flags & ACCESS_16BIT)
value = readw(dev->base + offset) |
(readw(dev->base + offset + 2) << 16);
else
value = readl(dev->base + offset);
if (dev->accessor_flags & ACCESS_SWAP)
return swab32(value);
else
return value;
}
void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
{
if (dev->accessor_flags & ACCESS_SWAP)
b = swab32(b);
if (dev->accessor_flags & ACCESS_16BIT) {
writew((u16)b, dev->base + offset);
writew((u16)(b >> 16), dev->base + offset + 2);
} else {
writel(b, dev->base + offset);
}
}
static u32
i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
{
/*
* DesignWare I2C core doesn't seem to have solid strategy to meet
* the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec
* will result in violation of the tHD;STA spec.
*/
if (cond)
/*
* Conditional expression:
*
* IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH
*
* This is based on the DW manuals, and represents an ideal
* configuration. The resulting I2C bus speed will be
* faster than any of the others.
*
* If your hardware is free from tHD;STA issue, try this one.
*/
return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset;
else
/*
* Conditional expression:
*
* IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf)
*
* This is just experimental rule; the tHD;STA period turned
* out to be proportinal to (_HCNT + 3). With this setting,
* we could meet both tHIGH and tHD;STA timing specs.
*
* If unsure, you'd better to take this alternative.
*
* The reason why we need to take into account "tf" here,
* is the same as described in i2c_dw_scl_lcnt().
*/
return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000
- 3 + offset;
}
static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
{
/*
* Conditional expression:
*
* IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf)
*
* DW I2C core starts counting the SCL CNTs for the LOW period
* of the SCL clock (tLOW) as soon as it pulls the SCL line.
* In order to meet the tLOW timing spec, we need to take into
* account the fall time of SCL signal (tf). Default tf value
* should be 0.3 us, for safety.
*/
return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset;
}
static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
{
int timeout = 100;
do {
dw_writel(dev, enable, DW_IC_ENABLE);
if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable)
return;
/*
* Wait 10 times the signaling period of the highest I2C
* transfer supported by the driver (for 400KHz this is
* 25us) as described in the DesignWare I2C databook.
*/
usleep_range(25, 250);
} while (timeout--);
dev_warn(dev->dev, "timeout in %sabling adapter\n",
enable ? "en" : "dis");
}
/**
* i2c_dw_init() - initialize the designware i2c master hardware
* @dev: device private data
*
* This functions configures and enables the I2C master.
* This function is called during I2C init function, and in case of timeout at
* run time.
*/
int i2c_dw_init(struct dw_i2c_dev *dev)
{
u32 input_clock_khz;
u32 hcnt, lcnt;
u32 reg;
u32 sda_falling_time, scl_falling_time;
input_clock_khz = dev->get_clk_rate_khz(dev);
reg = dw_readl(dev, DW_IC_COMP_TYPE);
if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
/* Configure register endianess access */
dev->accessor_flags |= ACCESS_SWAP;
} else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
/* Configure register access mode 16bit */
dev->accessor_flags |= ACCESS_16BIT;
} else if (reg != DW_IC_COMP_TYPE_VALUE) {
dev_err(dev->dev, "Unknown Synopsys component type: "
"0x%08x\n", reg);
return -ENODEV;
}
/* Disable the adapter */
__i2c_dw_enable(dev, false);
/* set standard and fast speed deviders for high/low periods */
sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
scl_falling_time = dev->scl_falling_time ?: 300; /* ns */
/* Standard-mode */
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
4000, /* tHD;STA = tHIGH = 4.0 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
4700, /* tLOW = 4.7 us */
scl_falling_time,
0); /* No offset */
/* Allow platforms to specify the ideal HCNT and LCNT values */
if (dev->ss_hcnt && dev->ss_lcnt) {
hcnt = dev->ss_hcnt;
lcnt = dev->ss_lcnt;
}
dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
/* Fast-mode */
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
600, /* tHD;STA = tHIGH = 0.6 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
1300, /* tLOW = 1.3 us */
scl_falling_time,
0); /* No offset */
if (dev->fs_hcnt && dev->fs_lcnt) {
hcnt = dev->fs_hcnt;
lcnt = dev->fs_lcnt;
}
dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
/* Configure SDA Hold Time if required */
if (dev->sda_hold_time) {
reg = dw_readl(dev, DW_IC_COMP_VERSION);
if (reg >= DW_IC_SDA_HOLD_MIN_VERS)
dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
else
dev_warn(dev->dev,
"Hardware too old to adjust SDA hold time.");
}
/* Configure Tx/Rx FIFO threshold levels */
dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
dw_writel(dev, 0, DW_IC_RX_TL);
/* configure the i2c master */
dw_writel(dev, dev->master_cfg , DW_IC_CON);
return 0;
}
EXPORT_SYMBOL_GPL(i2c_dw_init);
/*
* Waiting for bus not busy
*/
static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
{
int timeout = TIMEOUT;
while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
if (timeout <= 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return -ETIMEDOUT;
}
timeout--;
usleep_range(1000, 1100);
}
return 0;
}
static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
{
struct i2c_msg *msgs = dev->msgs;
u32 ic_con, ic_tar = 0;
/* Disable the adapter */
__i2c_dw_enable(dev, false);
/* if the slave address is ten bit address, enable 10BITADDR */
ic_con = dw_readl(dev, DW_IC_CON);
if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
ic_con |= DW_IC_CON_10BITADDR_MASTER;
/*
* If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing
* mode has to be enabled via bit 12 of IC_TAR register.
* We set it always as I2C_DYNAMIC_TAR_UPDATE can't be
* detected from registers.
*/
ic_tar = DW_IC_TAR_10BITADDR_MASTER;
} else {
ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
}
dw_writel(dev, ic_con, DW_IC_CON);
/*
* Set the slave (target) address and enable 10-bit addressing mode
* if applicable.
*/
dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR);
/* enforce disabled interrupts (due to HW issues) */
i2c_dw_disable_int(dev);
/* Enable the adapter */
__i2c_dw_enable(dev, true);
/* Clear and enable interrupts */
i2c_dw_clear_int(dev);
dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
}
/*
* Initiate (and continue) low level master read/write transaction.
* This function is only called from i2c_dw_isr, and pumping i2c_msg
* messages into the tx buffer. Even if the size of i2c_msg data is
* longer than the size of the tx buffer, it handles everything.
*/
static void
i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
{
struct i2c_msg *msgs = dev->msgs;
u32 intr_mask;
int tx_limit, rx_limit;
u32 addr = msgs[dev->msg_write_idx].addr;
u32 buf_len = dev->tx_buf_len;
u8 *buf = dev->tx_buf;
bool need_restart = false;
intr_mask = DW_IC_INTR_DEFAULT_MASK;
for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
/*
* if target address has changed, we need to
* reprogram the target address in the i2c
* adapter when we are done with this transfer
*/
if (msgs[dev->msg_write_idx].addr != addr) {
dev_err(dev->dev,
"%s: invalid target address\n", __func__);
dev->msg_err = -EINVAL;
break;
}
if (msgs[dev->msg_write_idx].len == 0) {
dev_err(dev->dev,
"%s: invalid message length\n", __func__);
dev->msg_err = -EINVAL;
break;
}
if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
/* new i2c_msg */
buf = msgs[dev->msg_write_idx].buf;
buf_len = msgs[dev->msg_write_idx].len;
/* If both IC_EMPTYFIFO_HOLD_MASTER_EN and
* IC_RESTART_EN are set, we must manually
* set restart bit between messages.
*/
if ((dev->master_cfg & DW_IC_CON_RESTART_EN) &&
(dev->msg_write_idx > 0))
need_restart = true;
}
tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);
while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
u32 cmd = 0;
/*
* If IC_EMPTYFIFO_HOLD_MASTER_EN is set we must
* manually set the stop bit. However, it cannot be
* detected from the registers so we set it always
* when writing/reading the last byte.
*/
if (dev->msg_write_idx == dev->msgs_num - 1 &&
buf_len == 1)
cmd |= BIT(9);
if (need_restart) {
cmd |= BIT(10);
need_restart = false;
}
if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
/* avoid rx buffer overrun */
if (rx_limit - dev->rx_outstanding <= 0)
break;
dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD);
rx_limit--;
dev->rx_outstanding++;
} else
dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD);
tx_limit--; buf_len--;
}
dev->tx_buf = buf;
dev->tx_buf_len = buf_len;
if (buf_len > 0) {
/* more bytes to be written */
dev->status |= STATUS_WRITE_IN_PROGRESS;
break;
} else
dev->status &= ~STATUS_WRITE_IN_PROGRESS;
}
/*
* If i2c_msg index search is completed, we don't need TX_EMPTY
* interrupt any more.
*/
if (dev->msg_write_idx == dev->msgs_num)
intr_mask &= ~DW_IC_INTR_TX_EMPTY;
if (dev->msg_err)
intr_mask = 0;
dw_writel(dev, intr_mask, DW_IC_INTR_MASK);
}
static void
i2c_dw_read(struct dw_i2c_dev *dev)
{
struct i2c_msg *msgs = dev->msgs;
int rx_valid;
for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
u32 len;
u8 *buf;
if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
continue;
if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
len = msgs[dev->msg_read_idx].len;
buf = msgs[dev->msg_read_idx].buf;
} else {
len = dev->rx_buf_len;
buf = dev->rx_buf;
}
rx_valid = dw_readl(dev, DW_IC_RXFLR);
for (; len > 0 && rx_valid > 0; len--, rx_valid--) {
*buf++ = dw_readl(dev, DW_IC_DATA_CMD);
dev->rx_outstanding--;
}
if (len > 0) {
dev->status |= STATUS_READ_IN_PROGRESS;
dev->rx_buf_len = len;
dev->rx_buf = buf;
return;
} else
dev->status &= ~STATUS_READ_IN_PROGRESS;
}
}
static int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
{
unsigned long abort_source = dev->abort_source;
int i;
if (abort_source & DW_IC_TX_ABRT_NOACK) {
for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
dev_dbg(dev->dev,
"%s: %s\n", __func__, abort_sources[i]);
return -EREMOTEIO;
}
for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
if (abort_source & DW_IC_TX_ARB_LOST)
return -EAGAIN;
else if (abort_source & DW_IC_TX_ABRT_GCALL_READ)
return -EINVAL; /* wrong msgs[] data */
else
return -EIO;
}
/*
* Prepare controller for a transaction and call i2c_dw_xfer_msg
*/
int
i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
int ret;
dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
mutex_lock(&dev->lock);
pm_runtime_get_sync(dev->dev);
reinit_completion(&dev->cmd_complete);
dev->msgs = msgs;
dev->msgs_num = num;
dev->cmd_err = 0;
dev->msg_write_idx = 0;
dev->msg_read_idx = 0;
dev->msg_err = 0;
dev->status = STATUS_IDLE;
dev->abort_source = 0;
dev->rx_outstanding = 0;
ret = i2c_dw_wait_bus_not_busy(dev);
if (ret < 0)
goto done;
/* start the transfers */
i2c_dw_xfer_init(dev);
/* wait for tx to complete */
ret = wait_for_completion_timeout(&dev->cmd_complete, HZ);
if (ret == 0) {
dev_err(dev->dev, "controller timed out\n");
/* i2c_dw_init implicitly disables the adapter */
i2c_dw_init(dev);
ret = -ETIMEDOUT;
goto done;
}
/*
* We must disable the adapter before unlocking the &dev->lock mutex
* below. Otherwise the hardware might continue generating interrupts
* which in turn causes a race condition with the following transfer.
* Needs some more investigation if the additional interrupts are
* a hardware bug or this driver doesn't handle them correctly yet.
*/
__i2c_dw_enable(dev, false);
if (dev->msg_err) {
ret = dev->msg_err;
goto done;
}
/* no error */
if (likely(!dev->cmd_err)) {
ret = num;
goto done;
}
/* We have an error */
if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
ret = i2c_dw_handle_tx_abort(dev);
goto done;
}
ret = -EIO;
done:
pm_runtime_mark_last_busy(dev->dev);
pm_runtime_put_autosuspend(dev->dev);
mutex_unlock(&dev->lock);
return ret;
}
EXPORT_SYMBOL_GPL(i2c_dw_xfer);
u32 i2c_dw_func(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
return dev->functionality;
}
EXPORT_SYMBOL_GPL(i2c_dw_func);
static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
{
u32 stat;
/*
* The IC_INTR_STAT register just indicates "enabled" interrupts.
* Ths unmasked raw version of interrupt status bits are available
* in the IC_RAW_INTR_STAT register.
*
* That is,
* stat = dw_readl(IC_INTR_STAT);
* equals to,
* stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
*
* The raw version might be useful for debugging purposes.
*/
stat = dw_readl(dev, DW_IC_INTR_STAT);
/*
* Do not use the IC_CLR_INTR register to clear interrupts, or
* you'll miss some interrupts, triggered during the period from
* dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
*
* Instead, use the separately-prepared IC_CLR_* registers.
*/
if (stat & DW_IC_INTR_RX_UNDER)
dw_readl(dev, DW_IC_CLR_RX_UNDER);
if (stat & DW_IC_INTR_RX_OVER)
dw_readl(dev, DW_IC_CLR_RX_OVER);
if (stat & DW_IC_INTR_TX_OVER)
dw_readl(dev, DW_IC_CLR_TX_OVER);
if (stat & DW_IC_INTR_RD_REQ)
dw_readl(dev, DW_IC_CLR_RD_REQ);
if (stat & DW_IC_INTR_TX_ABRT) {
/*
* The IC_TX_ABRT_SOURCE register is cleared whenever
* the IC_CLR_TX_ABRT is read. Preserve it beforehand.
*/
dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
dw_readl(dev, DW_IC_CLR_TX_ABRT);
}
if (stat & DW_IC_INTR_RX_DONE)
dw_readl(dev, DW_IC_CLR_RX_DONE);
if (stat & DW_IC_INTR_ACTIVITY)
dw_readl(dev, DW_IC_CLR_ACTIVITY);
if (stat & DW_IC_INTR_STOP_DET)
dw_readl(dev, DW_IC_CLR_STOP_DET);
if (stat & DW_IC_INTR_START_DET)
dw_readl(dev, DW_IC_CLR_START_DET);
if (stat & DW_IC_INTR_GEN_CALL)
dw_readl(dev, DW_IC_CLR_GEN_CALL);
return stat;
}
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
* occurs.
*/
irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
{
struct dw_i2c_dev *dev = dev_id;
u32 stat, enabled;
enabled = dw_readl(dev, DW_IC_ENABLE);
stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
dev_dbg(dev->dev, "%s: %s enabled= 0x%x stat=0x%x\n", __func__,
dev->adapter.name, enabled, stat);
if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
return IRQ_NONE;
stat = i2c_dw_read_clear_intrbits(dev);
if (stat & DW_IC_INTR_TX_ABRT) {
dev->cmd_err |= DW_IC_ERR_TX_ABRT;
dev->status = STATUS_IDLE;
/*
* Anytime TX_ABRT is set, the contents of the tx/rx
* buffers are flushed. Make sure to skip them.
*/
dw_writel(dev, 0, DW_IC_INTR_MASK);
goto tx_aborted;
}
if (stat & DW_IC_INTR_RX_FULL)
i2c_dw_read(dev);
if (stat & DW_IC_INTR_TX_EMPTY)
i2c_dw_xfer_msg(dev);
/*
* No need to modify or disable the interrupt mask here.
* i2c_dw_xfer_msg() will take care of it according to
* the current transmit status.
*/
tx_aborted:
if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
complete(&dev->cmd_complete);
return IRQ_HANDLED;
}
EXPORT_SYMBOL_GPL(i2c_dw_isr);
void i2c_dw_enable(struct dw_i2c_dev *dev)
{
/* Enable the adapter */
__i2c_dw_enable(dev, true);
}
EXPORT_SYMBOL_GPL(i2c_dw_enable);
u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev)
{
return dw_readl(dev, DW_IC_ENABLE);
}
EXPORT_SYMBOL_GPL(i2c_dw_is_enabled);
void i2c_dw_disable(struct dw_i2c_dev *dev)
{
/* Disable controller */
__i2c_dw_enable(dev, false);
/* Disable all interupts */
dw_writel(dev, 0, DW_IC_INTR_MASK);
dw_readl(dev, DW_IC_CLR_INTR);
}
EXPORT_SYMBOL_GPL(i2c_dw_disable);
void i2c_dw_clear_int(struct dw_i2c_dev *dev)
{
dw_readl(dev, DW_IC_CLR_INTR);
}
EXPORT_SYMBOL_GPL(i2c_dw_clear_int);
void i2c_dw_disable_int(struct dw_i2c_dev *dev)
{
dw_writel(dev, 0, DW_IC_INTR_MASK);
}
EXPORT_SYMBOL_GPL(i2c_dw_disable_int);
u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev)
{
return dw_readl(dev, DW_IC_COMP_PARAM_1);
}
EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param);
MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core");
MODULE_LICENSE("GPL");
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