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rt-thread/components/drivers/i2c/i2c-bit-ops.c

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/*
* File : i2c-bit-ops.c
* This file is part of RT-Thread RTOS
* COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Change Logs:
* Date Author Notes
* 2012-04-25 weety first version
*/
#include <rtdevice.h>
#ifdef RT_I2C_BIT_DEBUG
#define bit_dbg(fmt, ...) rt_kprintf(fmt, ##__VA_ARGS__)
#else
#define bit_dbg(fmt, ...)
#endif
#define SET_SDA(ops, val) ops->set_sda(ops->data, val)
#define SET_SCL(ops, val) ops->set_scl(ops->data, val)
#define GET_SDA(ops) ops->get_sda(ops->data)
#define GET_SCL(ops) ops->get_scl(ops->data)
rt_inline void i2c_delay(struct rt_i2c_bit_ops *ops)
{
ops->udelay((ops->delay_us + 1) >> 1);
}
rt_inline void i2c_delay2(struct rt_i2c_bit_ops *ops)
{
ops->udelay(ops->delay_us);
}
#define SDA_L(ops) SET_SDA(ops, 0)
#define SDA_H(ops) SET_SDA(ops, 1)
#define SCL_L(ops) SET_SCL(ops, 0)
/**
* release scl line, and wait scl line to high.
*/
static rt_err_t SCL_H(struct rt_i2c_bit_ops *ops)
{
rt_tick_t start;
SET_SCL(ops, 1);
if (!ops->get_scl)
goto done;
start = rt_tick_get();
while (!GET_SCL(ops))
{
if ((rt_tick_get() - start) > ops->timeout)
return -RT_ETIMEOUT;
rt_thread_delay((ops->timeout + 1) >> 1);
}
#ifdef RT_I2C_BIT_DEBUG
if (rt_tick_get() != start)
{
bit_dbg("wait %ld tick for SCL line to go high\n",
rt_tick_get() - start);
}
#endif
done:
i2c_delay(ops);
return RT_EOK;
}
static void i2c_start(struct rt_i2c_bit_ops *ops)
{
#ifdef RT_I2C_BIT_DEBUG
if (ops->get_scl && !GET_SCL(ops))
{
bit_dbg("I2C bus error, SCL line low\n");
}
if (ops->get_sda && !GET_SDA(ops))
{
bit_dbg("I2C bus error, SDA line low\n");
}
#endif
SDA_L(ops);
i2c_delay(ops);
SCL_L(ops);
}
static void i2c_restart(struct rt_i2c_bit_ops *ops)
{
SDA_H(ops);
SCL_H(ops);
i2c_delay(ops);
SDA_L(ops);
i2c_delay(ops);
SCL_L(ops);
}
static void i2c_stop(struct rt_i2c_bit_ops *ops)
{
SDA_L(ops);
i2c_delay(ops);
SCL_H(ops);
i2c_delay(ops);
SDA_H(ops);
i2c_delay2(ops);
}
rt_inline rt_bool_t i2c_waitack(struct rt_i2c_bit_ops *ops)
{
rt_bool_t ack;
SDA_H(ops);
i2c_delay(ops);
if (SCL_H(ops) < 0)
{
bit_dbg("wait ack timeout\n");
return -RT_ETIMEOUT;
}
ack = !GET_SDA(ops); /* ACK : SDA pin is pulled low */
bit_dbg("%s\n", ack ? "ACK" : "NACK");
SCL_L(ops);
return ack;
}
static rt_int32_t i2c_writeb(struct rt_i2c_bus_device *bus, rt_uint8_t data)
{
rt_int32_t i;
rt_uint8_t bit;
struct rt_i2c_bit_ops *ops = bus->priv;
for (i = 7; i >= 0; i--)
{
SCL_L(ops);
bit = (data >> i) & 1;
SET_SDA(ops, bit);
i2c_delay(ops);
if (SCL_H(ops) < 0)
{
bit_dbg("i2c_writeb: 0x%02x, "
"wait scl pin high timeout at bit %d\n",
data, i);
return -RT_ETIMEOUT;
}
}
SCL_L(ops);
i2c_delay(ops);
return i2c_waitack(ops);
}
static rt_int32_t i2c_readb(struct rt_i2c_bus_device *bus)
{
rt_uint8_t i;
rt_uint8_t data = 0;
struct rt_i2c_bit_ops *ops = bus->priv;
SDA_H(ops);
i2c_delay(ops);
for (i = 0; i < 8; i++)
{
data <<= 1;
if (SCL_H(ops) < 0)
{
bit_dbg("i2c_readb: wait scl pin high "
"timeout at bit %d\n", 7 - i);
return -RT_ETIMEOUT;
}
if (GET_SDA(ops))
data |= 1;
SCL_L(ops);
i2c_delay2(ops);
}
return data;
}
static rt_size_t i2c_send_bytes(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg *msg)
{
rt_int32_t ret;
rt_size_t bytes = 0;
const rt_uint8_t *ptr = msg->buf;
rt_int32_t count = msg->len;
rt_uint16_t ignore_nack = msg->flags & RT_I2C_IGNORE_NACK;
while (count > 0)
{
ret = i2c_writeb(bus, *ptr);
if ((ret > 0) || (ignore_nack && (ret == 0)))
{
count --;
ptr ++;
bytes ++;
}
else if (ret == 0)
{
i2c_dbg("send bytes: NACK.\n");
return 0;
}
else
{
i2c_dbg("send bytes: error %d\n", ret);
return ret;
}
}
return bytes;
}
static rt_err_t i2c_send_ack_or_nack(struct rt_i2c_bus_device *bus, int ack)
{
struct rt_i2c_bit_ops *ops = bus->priv;
if (ack)
SET_SDA(ops, 0);
i2c_delay(ops);
if (SCL_H(ops) < 0)
{
bit_dbg("ACK or NACK timeout\n");
return -RT_ETIMEOUT;
}
SCL_L(ops);
return RT_EOK;
}
static rt_size_t i2c_recv_bytes(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg *msg)
{
rt_int32_t val;
rt_int32_t bytes = 0; /* actual bytes */
rt_uint8_t *ptr = msg->buf;
rt_int32_t count = msg->len;
const rt_uint32_t flags = msg->flags;
while (count > 0)
{
val = i2c_readb(bus);
if (val >= 0)
{
*ptr = val;
bytes ++;
}
else
{
break;
}
ptr ++;
count --;
bit_dbg("recieve bytes: 0x%02x, %s\n",
val, (flags & RT_I2C_NO_READ_ACK) ?
"(No ACK/NACK)" : (count ? "ACK" : "NACK"));
if (!(flags & RT_I2C_NO_READ_ACK))
{
val = i2c_send_ack_or_nack(bus, count);
if (val < 0)
return val;
}
}
return bytes;
}
static rt_int32_t i2c_send_address(struct rt_i2c_bus_device *bus,
rt_uint8_t addr,
rt_int32_t retries)
{
struct rt_i2c_bit_ops *ops = bus->priv;
rt_int32_t i;
rt_err_t ret = 0;
for (i = 0; i <= retries; i++)
{
ret = i2c_writeb(bus, addr);
if (ret == 1 || i == retries)
break;
bit_dbg("send stop condition\n");
i2c_stop(ops);
i2c_delay2(ops);
bit_dbg("send start condition\n");
i2c_start(ops);
}
return ret;
}
static rt_err_t i2c_bit_send_address(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg *msg)
{
rt_uint16_t flags = msg->flags;
rt_uint16_t ignore_nack = msg->flags & RT_I2C_IGNORE_NACK;
struct rt_i2c_bit_ops *ops = bus->priv;
rt_uint8_t addr1, addr2;
rt_int32_t retries;
rt_err_t ret;
retries = ignore_nack ? 0 : bus->retries;
if (flags & RT_I2C_ADDR_10BIT)
{
addr1 = 0xf0 | ((msg->addr >> 7) & 0x06);
addr2 = msg->addr & 0xff;
bit_dbg("addr1: %d, addr2: %d\n", addr1, addr2);
ret = i2c_send_address(bus, addr1, retries);
if ((ret != 1) && !ignore_nack)
{
bit_dbg("NACK: sending first addr\n");
return -RT_EIO;
}
ret = i2c_writeb(bus, addr2);
if ((ret != 1) && !ignore_nack)
{
bit_dbg("NACK: sending second addr\n");
return -RT_EIO;
}
if (flags & RT_I2C_RD)
{
bit_dbg("send repeated start condition\n");
i2c_restart(ops);
addr1 |= 0x01;
ret = i2c_send_address(bus, addr1, retries);
if ((ret != 1) && !ignore_nack)
{
bit_dbg("NACK: sending repeated addr\n");
return -RT_EIO;
}
}
}
else
{
/* 7-bit addr */
addr1 = msg->addr << 1;
if (flags & RT_I2C_RD)
addr1 |= 1;
ret = i2c_send_address(bus, addr1, retries);
if ((ret != 1) && !ignore_nack)
return -RT_EIO;
}
return RT_EOK;
}
static rt_size_t i2c_bit_xfer(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num)
{
struct rt_i2c_msg *msg;
struct rt_i2c_bit_ops *ops = bus->priv;
rt_int32_t i, ret;
rt_uint16_t ignore_nack;
bit_dbg("send start condition\n");
i2c_start(ops);
for (i = 0; i < num; i++)
{
msg = &msgs[i];
ignore_nack = msg->flags & RT_I2C_IGNORE_NACK;
if (!(msg->flags & RT_I2C_NO_START))
{
if (i)
{
i2c_restart(ops);
}
ret = i2c_bit_send_address(bus, msg);
if ((ret != RT_EOK) && !ignore_nack)
{
bit_dbg("receive NACK from device addr 0x%02x msg %d\n",
msgs[i].addr, i);
goto out;
}
}
if (msg->flags & RT_I2C_RD)
{
ret = i2c_recv_bytes(bus, msg);
if (ret >= 1)
bit_dbg("read %d byte%s\n", ret, ret == 1 ? "" : "s");
if (ret < msg->len)
{
if (ret >= 0)
ret = -RT_EIO;
goto out;
}
}
else
{
ret = i2c_send_bytes(bus, msg);
if (ret >= 1)
bit_dbg("write %d byte%s\n", ret, ret == 1 ? "" : "s");
if (ret < msg->len)
{
if (ret >= 0)
ret = -RT_ERROR;
goto out;
}
}
}
ret = i;
out:
bit_dbg("send stop condition\n");
i2c_stop(ops);
return ret;
}
static const struct rt_i2c_bus_device_ops i2c_bit_bus_ops =
{
i2c_bit_xfer,
RT_NULL,
RT_NULL
};
rt_err_t rt_i2c_bit_add_bus(struct rt_i2c_bus_device *bus,
const char *bus_name)
{
bus->ops = &i2c_bit_bus_ops;
return rt_i2c_bus_device_register(bus, bus_name);
}
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