linux/drivers/i2c/busses/i2c-designware.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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* ----------------------------------------------------------------------------
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.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_COMP_PARAM_1 0xf4
#define DW_IC_TX_ABRT_SOURCE 0x80
#define DW_IC_CON_MASTER 0x1
#define DW_IC_CON_SPEED_STD 0x2
#define DW_IC_CON_SPEED_FAST 0x4
#define DW_IC_CON_10BITADDR_MASTER 0x10
#define DW_IC_CON_RESTART_EN 0x20
#define DW_IC_CON_SLAVE_DISABLE 0x40
#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
/*
* 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",
};
/**
* struct dw_i2c_dev - private i2c-designware data
* @dev: driver model device node
* @base: IO registers pointer
* @cmd_complete: tx completion indicator
* @lock: protect this struct and IO registers
* @clk: input reference clock
* @cmd_err: run time hadware error code
* @msgs: points to an array of messages currently being transferred
* @msgs_num: the number of elements in msgs
* @msg_write_idx: the element index of the current tx message in the msgs
* array
* @tx_buf_len: the length of the current tx buffer
* @tx_buf: the current tx buffer
* @msg_read_idx: the element index of the current rx message in the msgs
* array
* @rx_buf_len: the length of the current rx buffer
* @rx_buf: the current rx buffer
* @msg_err: error status of the current transfer
* @status: i2c master status, one of STATUS_*
* @abort_source: copy of the TX_ABRT_SOURCE register
* @irq: interrupt number for the i2c master
* @adapter: i2c subsystem adapter node
* @tx_fifo_depth: depth of the hardware tx fifo
* @rx_fifo_depth: depth of the hardware rx fifo
*/
struct dw_i2c_dev {
struct device *dev;
void __iomem *base;
struct completion cmd_complete;
struct mutex lock;
struct clk *clk;
int cmd_err;
struct i2c_msg *msgs;
int msgs_num;
int msg_write_idx;
u32 tx_buf_len;
u8 *tx_buf;
int msg_read_idx;
u32 rx_buf_len;
u8 *rx_buf;
int msg_err;
unsigned int status;
u32 abort_source;
int irq;
struct i2c_adapter adapter;
unsigned int tx_fifo_depth;
unsigned int rx_fifo_depth;
};
i2c-designware: Improved _HCNT/_LCNT calculation * Calculate with accurate conditional expressions from DW manuals. * Round ic_clk by adding 0.5 as it's important at high ic_clk rate. * Take into account "tHD;STA" issue for _HCNT calculation. * Take into account "tf" for _LCNT calculation. * Add "cond" and "offset" fot further correction requirements. For _HCNT calculation, there's one issue needs to be carefully considered; DesignWare I2C core doesn't seem to have solid strategy to meet the tHD;STA timing spec. If you configure _HCNT based on the tHIGH timing spec, it easily results in violation of the tHD;STA spec. After many trials, we came to the conclusion that the tHD;STA period is proportional to (_HCNT + 3). For the safety's sake, this should be selected by default. As for _LCNT calculation, DW I2C core has one characteristic behavior; he starts counting the SCL CNTs for the LOW period of the SCL clock (tLOW) as soon as it pulls the SCL line. At that time, he doesn't take into account the fall time of SCL signal (tf), IOW, he starts counting CNTs without confirming the SCL input voltage has dropped to below VIL. This characteristics becomes a problem on some platforms where tf is considerably long, and results in violation of the tLOW timing spec. To make the driver configurable as much as possible for various cases, we'd have separated arguments "tf" and "offset", and for safety default values should be 0.3 us and 0, respectively. Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com> Acked-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-11-06 12:47:01 +00:00
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 + 5000) / 10000 - 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) + 5000) / 10000 - 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) + 5000) / 10000) - 1 + offset;
}
/**
* 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.
*/
static void i2c_dw_init(struct dw_i2c_dev *dev)
{
u32 input_clock_khz = clk_get_rate(dev->clk) / 1000;
i2c-designware: Improved _HCNT/_LCNT calculation * Calculate with accurate conditional expressions from DW manuals. * Round ic_clk by adding 0.5 as it's important at high ic_clk rate. * Take into account "tHD;STA" issue for _HCNT calculation. * Take into account "tf" for _LCNT calculation. * Add "cond" and "offset" fot further correction requirements. For _HCNT calculation, there's one issue needs to be carefully considered; DesignWare I2C core doesn't seem to have solid strategy to meet the tHD;STA timing spec. If you configure _HCNT based on the tHIGH timing spec, it easily results in violation of the tHD;STA spec. After many trials, we came to the conclusion that the tHD;STA period is proportional to (_HCNT + 3). For the safety's sake, this should be selected by default. As for _LCNT calculation, DW I2C core has one characteristic behavior; he starts counting the SCL CNTs for the LOW period of the SCL clock (tLOW) as soon as it pulls the SCL line. At that time, he doesn't take into account the fall time of SCL signal (tf), IOW, he starts counting CNTs without confirming the SCL input voltage has dropped to below VIL. This characteristics becomes a problem on some platforms where tf is considerably long, and results in violation of the tLOW timing spec. To make the driver configurable as much as possible for various cases, we'd have separated arguments "tf" and "offset", and for safety default values should be 0.3 us and 0, respectively. Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com> Acked-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-11-06 12:47:01 +00:00
u32 ic_con, hcnt, lcnt;
/* Disable the adapter */
writel(0, dev->base + DW_IC_ENABLE);
/* set standard and fast speed deviders for high/low periods */
i2c-designware: Improved _HCNT/_LCNT calculation * Calculate with accurate conditional expressions from DW manuals. * Round ic_clk by adding 0.5 as it's important at high ic_clk rate. * Take into account "tHD;STA" issue for _HCNT calculation. * Take into account "tf" for _LCNT calculation. * Add "cond" and "offset" fot further correction requirements. For _HCNT calculation, there's one issue needs to be carefully considered; DesignWare I2C core doesn't seem to have solid strategy to meet the tHD;STA timing spec. If you configure _HCNT based on the tHIGH timing spec, it easily results in violation of the tHD;STA spec. After many trials, we came to the conclusion that the tHD;STA period is proportional to (_HCNT + 3). For the safety's sake, this should be selected by default. As for _LCNT calculation, DW I2C core has one characteristic behavior; he starts counting the SCL CNTs for the LOW period of the SCL clock (tLOW) as soon as it pulls the SCL line. At that time, he doesn't take into account the fall time of SCL signal (tf), IOW, he starts counting CNTs without confirming the SCL input voltage has dropped to below VIL. This characteristics becomes a problem on some platforms where tf is considerably long, and results in violation of the tLOW timing spec. To make the driver configurable as much as possible for various cases, we'd have separated arguments "tf" and "offset", and for safety default values should be 0.3 us and 0, respectively. Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com> Acked-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-11-06 12:47:01 +00:00
/* Standard-mode */
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
40, /* tHD;STA = tHIGH = 4.0 us */
3, /* tf = 0.3 us */
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
47, /* tLOW = 4.7 us */
3, /* tf = 0.3 us */
0); /* No offset */
writel(hcnt, dev->base + DW_IC_SS_SCL_HCNT);
writel(lcnt, dev->base + 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,
6, /* tHD;STA = tHIGH = 0.6 us */
3, /* tf = 0.3 us */
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
13, /* tLOW = 1.3 us */
3, /* tf = 0.3 us */
0); /* No offset */
writel(hcnt, dev->base + DW_IC_FS_SCL_HCNT);
writel(lcnt, dev->base + DW_IC_FS_SCL_LCNT);
dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
/* Configure Tx/Rx FIFO threshold levels */
writel(dev->tx_fifo_depth - 1, dev->base + DW_IC_TX_TL);
writel(0, dev->base + DW_IC_RX_TL);
/* configure the i2c master */
ic_con = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
writel(ic_con, dev->base + DW_IC_CON);
}
/*
* Waiting for bus not busy
*/
static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
{
int timeout = TIMEOUT;
while (readl(dev->base + DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
if (timeout <= 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return -ETIMEDOUT;
}
timeout--;
mdelay(1);
}
return 0;
}
static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
{
struct i2c_msg *msgs = dev->msgs;
u32 ic_con;
/* Disable the adapter */
writel(0, dev->base + DW_IC_ENABLE);
/* set the slave (target) address */
writel(msgs[dev->msg_write_idx].addr, dev->base + DW_IC_TAR);
/* if the slave address is ten bit address, enable 10BITADDR */
ic_con = readl(dev->base + DW_IC_CON);
if (msgs[dev->msg_write_idx].flags & I2C_M_TEN)
ic_con |= DW_IC_CON_10BITADDR_MASTER;
else
ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
writel(ic_con, dev->base + DW_IC_CON);
/* Enable the adapter */
writel(1, dev->base + DW_IC_ENABLE);
/* Enable interrupts */
writel(DW_IC_INTR_DEFAULT_MASK, dev->base + 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;;
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;
}
tx_limit = dev->tx_fifo_depth - readl(dev->base + DW_IC_TXFLR);
rx_limit = dev->rx_fifo_depth - readl(dev->base + DW_IC_RXFLR);
while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
writel(0x100, dev->base + DW_IC_DATA_CMD);
rx_limit--;
} else
writel(*buf++, dev->base + 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;
writel(intr_mask, dev->base + 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 = readl(dev->base + DW_IC_RXFLR);
for (; len > 0 && rx_valid > 0; len--, rx_valid--)
*buf++ = readl(dev->base + DW_IC_DATA_CMD);
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);
mutex_lock(&dev->lock);
INIT_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;
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_interruptible_timeout(&dev->cmd_complete, HZ);
if (ret == 0) {
dev_err(dev->dev, "controller timed out\n");
i2c_dw_init(dev);
ret = -ETIMEDOUT;
goto done;
} else if (ret < 0)
goto done;
if (dev->msg_err) {
ret = dev->msg_err;
goto done;
}
/* no error */
if (likely(!dev->cmd_err)) {
/* Disable the adapter */
writel(0, dev->base + DW_IC_ENABLE);
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:
mutex_unlock(&dev->lock);
return ret;
}
static u32 i2c_dw_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C |
I2C_FUNC_10BIT_ADDR |
I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_I2C_BLOCK;
}
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 = readl(IC_INTR_STAT);
* equals to,
* stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK);
*
* The raw version might be useful for debugging purposes.
*/
stat = readl(dev->base + 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
* readl(IC_INTR_STAT) to readl(IC_CLR_INTR).
*
* Instead, use the separately-prepared IC_CLR_* registers.
*/
if (stat & DW_IC_INTR_RX_UNDER)
readl(dev->base + DW_IC_CLR_RX_UNDER);
if (stat & DW_IC_INTR_RX_OVER)
readl(dev->base + DW_IC_CLR_RX_OVER);
if (stat & DW_IC_INTR_TX_OVER)
readl(dev->base + DW_IC_CLR_TX_OVER);
if (stat & DW_IC_INTR_RD_REQ)
readl(dev->base + 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 = readl(dev->base + DW_IC_TX_ABRT_SOURCE);
readl(dev->base + DW_IC_CLR_TX_ABRT);
}
if (stat & DW_IC_INTR_RX_DONE)
readl(dev->base + DW_IC_CLR_RX_DONE);
if (stat & DW_IC_INTR_ACTIVITY)
readl(dev->base + DW_IC_CLR_ACTIVITY);
if (stat & DW_IC_INTR_STOP_DET)
readl(dev->base + DW_IC_CLR_STOP_DET);
if (stat & DW_IC_INTR_START_DET)
readl(dev->base + DW_IC_CLR_START_DET);
if (stat & DW_IC_INTR_GEN_CALL)
readl(dev->base + 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;
stat = i2c_dw_read_clear_intrbits(dev);
dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
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.
*/
writel(0, dev->base + 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;
}
static struct i2c_algorithm i2c_dw_algo = {
.master_xfer = i2c_dw_xfer,
.functionality = i2c_dw_func,
};
static int __devinit dw_i2c_probe(struct platform_device *pdev)
{
struct dw_i2c_dev *dev;
struct i2c_adapter *adap;
struct resource *mem, *ioarea;
int irq, r;
/* NOTE: driver uses the static register mapping */
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem) {
dev_err(&pdev->dev, "no mem resource?\n");
return -EINVAL;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "no irq resource?\n");
return irq; /* -ENXIO */
}
ioarea = request_mem_region(mem->start, resource_size(mem),
pdev->name);
if (!ioarea) {
dev_err(&pdev->dev, "I2C region already claimed\n");
return -EBUSY;
}
dev = kzalloc(sizeof(struct dw_i2c_dev), GFP_KERNEL);
if (!dev) {
r = -ENOMEM;
goto err_release_region;
}
init_completion(&dev->cmd_complete);
mutex_init(&dev->lock);
dev->dev = get_device(&pdev->dev);
dev->irq = irq;
platform_set_drvdata(pdev, dev);
dev->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk)) {
r = -ENODEV;
goto err_free_mem;
}
clk_enable(dev->clk);
dev->base = ioremap(mem->start, resource_size(mem));
if (dev->base == NULL) {
dev_err(&pdev->dev, "failure mapping io resources\n");
r = -EBUSY;
goto err_unuse_clocks;
}
{
u32 param1 = readl(dev->base + DW_IC_COMP_PARAM_1);
dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
}
i2c_dw_init(dev);
writel(0, dev->base + DW_IC_INTR_MASK); /* disable IRQ */
r = request_irq(dev->irq, i2c_dw_isr, IRQF_DISABLED, pdev->name, dev);
if (r) {
dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
goto err_iounmap;
}
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_HWMON;
strlcpy(adap->name, "Synopsys DesignWare I2C adapter",
sizeof(adap->name));
adap->algo = &i2c_dw_algo;
adap->dev.parent = &pdev->dev;
adap->nr = pdev->id;
r = i2c_add_numbered_adapter(adap);
if (r) {
dev_err(&pdev->dev, "failure adding adapter\n");
goto err_free_irq;
}
return 0;
err_free_irq:
free_irq(dev->irq, dev);
err_iounmap:
iounmap(dev->base);
err_unuse_clocks:
clk_disable(dev->clk);
clk_put(dev->clk);
dev->clk = NULL;
err_free_mem:
platform_set_drvdata(pdev, NULL);
put_device(&pdev->dev);
kfree(dev);
err_release_region:
release_mem_region(mem->start, resource_size(mem));
return r;
}
static int __devexit dw_i2c_remove(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
struct resource *mem;
platform_set_drvdata(pdev, NULL);
i2c_del_adapter(&dev->adapter);
put_device(&pdev->dev);
clk_disable(dev->clk);
clk_put(dev->clk);
dev->clk = NULL;
writel(0, dev->base + DW_IC_ENABLE);
free_irq(dev->irq, dev);
kfree(dev);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(mem->start, resource_size(mem));
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_designware");
static struct platform_driver dw_i2c_driver = {
.remove = __devexit_p(dw_i2c_remove),
.driver = {
.name = "i2c_designware",
.owner = THIS_MODULE,
},
};
static int __init dw_i2c_init_driver(void)
{
return platform_driver_probe(&dw_i2c_driver, dw_i2c_probe);
}
module_init(dw_i2c_init_driver);
static void __exit dw_i2c_exit_driver(void)
{
platform_driver_unregister(&dw_i2c_driver);
}
module_exit(dw_i2c_exit_driver);
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
MODULE_LICENSE("GPL");