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linux/drivers/i2c/busses/i2c-designware-core.c
Zhuo-hao Lee 664d58bf4d i2c: designware: save the preset value of DW_IC_SDA_HOLD 
There are several ways to set the SDA hold time for i2c controller,
including: Device Tree, built-in device properties and ACPI. However,
if the SDA hold time is not specified by above method, we should
read the value, where it is preset by firmware, and save it to
sda_hold_time. This is needed because when i2c controller enters
runtime suspend, the DW_IC_SDA_HOLD value will be reset to chipset
default value. And during runtime resume, i2c_dw_init will be called
to reconfigure i2c controller. If sda_hold_time is zero, the chipset
default hold time will be used, that will be too short for some
platforms. Therefore, to have a better tolerance, the DW_IC_SDA_HOLD
value should be kept by sda_hold_time.

Signed-off-by: Zhuo-hao Lee <zhuo-hao.lee@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-09-08 22:14:36 +02:00

906 lines
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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",
};
static u32 dw_readl(struct dw_i2c_dev *dev, int offset)
{
u32 value;
if (dev->accessor_flags & ACCESS_16BIT)
value = readw_relaxed(dev->base + offset) |
(readw_relaxed(dev->base + offset + 2) << 16);
else
value = readl_relaxed(dev->base + offset);
if (dev->accessor_flags & ACCESS_SWAP)
return swab32(value);
else
return value;
}
static 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_relaxed((u16)b, dev->base + offset);
writew_relaxed((u16)(b >> 16), dev->base + offset + 2);
} else {
writel_relaxed(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");
}
static unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
{
/*
* Clock is not necessary if we got LCNT/HCNT values directly from
* the platform code.
*/
if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
return 0;
return dev->get_clk_rate_khz(dev);
}
/**
* 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 hcnt, lcnt;
u32 reg;
u32 sda_falling_time, scl_falling_time;
int ret;
if (dev->acquire_lock) {
ret = dev->acquire_lock(dev);
if (ret) {
dev_err(dev->dev, "couldn't acquire bus ownership\n");
return ret;
}
}
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);
if (dev->release_lock)
dev->release_lock(dev);
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 */
/* Set SCL timing parameters for standard-mode */
if (dev->ss_hcnt && dev->ss_lcnt) {
hcnt = dev->ss_hcnt;
lcnt = dev->ss_lcnt;
} else {
hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
4000, /* tHD;STA = tHIGH = 4.0 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
4700, /* tLOW = 4.7 us */
scl_falling_time,
0); /* No offset */
}
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);
/* Set SCL timing parameters for fast-mode */
if (dev->fs_hcnt && dev->fs_lcnt) {
hcnt = dev->fs_hcnt;
lcnt = dev->fs_lcnt;
} else {
hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
600, /* tHD;STA = tHIGH = 0.6 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
1300, /* tLOW = 1.3 us */
scl_falling_time,
0); /* No offset */
}
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 */
reg = dw_readl(dev, DW_IC_COMP_VERSION);
if (reg >= DW_IC_SDA_HOLD_MIN_VERS) {
if (dev->sda_hold_time) {
dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
} else {
/* Keep previous hold time setting if no one set it */
dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD);
}
} else {
dev_warn(dev->dev,
"Hardware too old to adjust SDA hold time.\n");
}
/* 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);
if (dev->release_lock)
dev->release_lock(dev);
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 */
dw_readl(dev, DW_IC_CLR_INTR);
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
*/
static 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);
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;
if (dev->acquire_lock) {
ret = dev->acquire_lock(dev);
if (ret) {
dev_err(dev->dev, "couldn't acquire bus ownership\n");
goto done_nolock;
}
}
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 */
if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
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 returning and signaling the end
* of the current transfer. 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:
if (dev->release_lock)
dev->release_lock(dev);
done_nolock:
pm_runtime_mark_last_busy(dev->dev);
pm_runtime_put_autosuspend(dev->dev);
return ret;
}
static u32 i2c_dw_func(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
return dev->functionality;
}
static struct i2c_algorithm i2c_dw_algo = {
.master_xfer = i2c_dw_xfer,
.functionality = 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.
*/
static 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: enabled=%#x stat=%#x\n", __func__, 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);
else if (unlikely(dev->accessor_flags & ACCESS_INTR_MASK)) {
/* workaround to trigger pending interrupt */
stat = dw_readl(dev, DW_IC_INTR_MASK);
i2c_dw_disable_int(dev);
dw_writel(dev, stat, DW_IC_INTR_MASK);
}
return IRQ_HANDLED;
}
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_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);
int i2c_dw_probe(struct dw_i2c_dev *dev)
{
struct i2c_adapter *adap = &dev->adapter;
int r;
init_completion(&dev->cmd_complete);
r = i2c_dw_init(dev);
if (r)
return r;
snprintf(adap->name, sizeof(adap->name),
"Synopsys DesignWare I2C adapter");
adap->retries = 3;
adap->algo = &i2c_dw_algo;
adap->dev.parent = dev->dev;
i2c_set_adapdata(adap, dev);
i2c_dw_disable_int(dev);
r = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr,
IRQF_SHARED | IRQF_COND_SUSPEND,
dev_name(dev->dev), dev);
if (r) {
dev_err(dev->dev, "failure requesting irq %i: %d\n",
dev->irq, r);
return r;
}
/*
* Increment PM usage count during adapter registration in order to
* avoid possible spurious runtime suspend when adapter device is
* registered to the device core and immediate resume in case bus has
* registered I2C slaves that do I2C transfers in their probe.
*/
pm_runtime_get_noresume(dev->dev);
r = i2c_add_numbered_adapter(adap);
if (r)
dev_err(dev->dev, "failure adding adapter: %d\n", r);
pm_runtime_put_noidle(dev->dev);
return r;
}
EXPORT_SYMBOL_GPL(i2c_dw_probe);
MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core");
MODULE_LICENSE("GPL");
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