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/*
* Synopsys DesignWare I2C adapter driver.
*
* 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/delay.h>
#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/module.h>
#include <linux/pm_runtime.h>
#include "i2c-designware-core.h"
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->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->flags & ACCESS_SWAP)
return swab32(value);
else
return value;
}
void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
{
if (dev->flags & ACCESS_SWAP)
b = swab32(b);
if (dev->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);
}
}
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;
}
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;
}
void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
{
dw_writel(dev, enable, DW_IC_ENABLE);
}
void __i2c_dw_enable_and_wait(struct dw_i2c_dev *dev, bool enable)
{
int timeout = 100;
do {
__i2c_dw_enable(dev, 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");
}
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);
}
int i2c_dw_acquire_lock(struct dw_i2c_dev *dev)
{
int ret;
if (!dev->acquire_lock)
return 0;
ret = dev->acquire_lock(dev);
if (!ret)
return 0;
dev_err(dev->dev, "couldn't acquire bus ownership\n");
return ret;
}
void i2c_dw_release_lock(struct dw_i2c_dev *dev)
{
if (dev->release_lock)
dev->release_lock(dev);
}
/*
* Waiting for bus not busy
*/
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;
}
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;
}
u32 i2c_dw_func(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
return dev->functionality;
}
void i2c_dw_disable(struct dw_i2c_dev *dev)
{
/* Disable controller */
__i2c_dw_enable_and_wait(dev, false);
/* Disable all interupts */
dw_writel(dev, 0, DW_IC_INTR_MASK);
dw_readl(dev, DW_IC_CLR_INTR);
}
void i2c_dw_disable_int(struct dw_i2c_dev *dev)
{
dw_writel(dev, 0, DW_IC_INTR_MASK);
}
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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