mirror of
https://github.com/apache/nuttx.git
synced 2026-05-22 05:42:05 +08:00
drivers/i2c: add ioexpander-based lower-half implementation for I2C bit-bang
This commit adds a new lower-half driver implementation for I2C bit-bang
that uses IO expander pins as the GPIO backend, enabling I2C bit-bang
functionality on systems where direct GPIO access is not available or
when I2C needs to be implemented using IO expander pins.
Background:
The existing I2C bit-bang driver (i2c_bitbang.c) provides a generic
upper-half implementation that requires a platform-specific lower-half
to control the SDA and SCL GPIO lines. Previously, each platform had to
implement its own lower-half using direct GPIO access.
Usage Example:
FAR struct ioexpander_dev_s *ioe = /* get IO expander */;
FAR struct i2c_master_s *i2c;
/* Initialize I2C bit-bang using IO expander pins 10 (SCL) and 11 (SDA) */
i2c = i2c_bitbang_ioexpander_initialize(ioe, 10, 11, 0);
if (i2c)
{
/* Use i2c master device normally */
}
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
This commit is contained in:
dongjiuzhu1
Xiang Xiao
@@ -29,6 +29,11 @@ if(CONFIG_I2C)
|
||||
|
||||
if(CONFIG_I2C_BITBANG)
|
||||
list(APPEND SRCS i2c_bitbang.c)
|
||||
|
||||
if(CONFIG_I2C_BITBANG_IOEXPANDER)
|
||||
list(APPEND SRCS i2c_bitbang_ioexpander.c)
|
||||
endif()
|
||||
|
||||
endif()
|
||||
|
||||
if(CONFIG_I2C_SLAVE_DRIVER)
|
||||
|
||||
@@ -112,6 +112,13 @@ config I2C_BITBANG_CLOCK_STRETCHING
|
||||
the pin into open-collector mode (master sets SCL high and waits until
|
||||
slave stops holding it low).
|
||||
|
||||
config I2C_BITBANG_IOEXPANDER
|
||||
bool "Support the ioexpander lower half of i2c bitbang"
|
||||
default n
|
||||
depends on IOEXPANDER
|
||||
---help---
|
||||
Using ioexpander to control gpio to implement i2c bitbang function.
|
||||
|
||||
endif # I2C_BITBANG
|
||||
|
||||
config I2C_DRIVER
|
||||
|
||||
@@ -32,6 +32,11 @@ endif
|
||||
|
||||
ifeq ($(CONFIG_I2C_BITBANG),y)
|
||||
CSRCS += i2c_bitbang.c
|
||||
|
||||
ifeq ($(CONFIG_I2C_BITBANG_IOEXPANDER),y)
|
||||
CSRCS += i2c_bitbang_ioexpander.c
|
||||
endif
|
||||
|
||||
endif
|
||||
|
||||
ifeq ($(CONFIG_I2C_SLAVE_DRIVER),y)
|
||||
|
||||
@@ -0,0 +1,276 @@
|
||||
/****************************************************************************
|
||||
* drivers/i2c/i2c_bitbang_ioexpander.c
|
||||
*
|
||||
* Licensed to the Apache Software Foundation (ASF) under one or more
|
||||
* contributor license agreements. See the NOTICE file distributed with
|
||||
* this work for additional information regarding copyright ownership. The
|
||||
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
||||
* "License"); you may not use this file except in compliance with the
|
||||
* License. You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing, software
|
||||
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||
* License for the specific language governing permissions and limitations
|
||||
* under the License.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Included Files
|
||||
****************************************************************************/
|
||||
|
||||
#include <assert.h>
|
||||
#include <debug.h>
|
||||
#include <stdbool.h>
|
||||
|
||||
#include <nuttx/kmalloc.h>
|
||||
#include <nuttx/i2c/i2c_bitbang.h>
|
||||
#include <nuttx/i2c/i2c_bitbang_ioexpander.h>
|
||||
|
||||
/****************************************************************************
|
||||
* Private Types
|
||||
****************************************************************************/
|
||||
|
||||
struct i2c_bb_ioe_s
|
||||
{
|
||||
struct i2c_bitbang_lower_dev_s lower;
|
||||
FAR struct ioexpander_dev_s *ioe;
|
||||
int sda_pin;
|
||||
int scl_pin;
|
||||
};
|
||||
|
||||
/****************************************************************************
|
||||
* Private Function Prototypes
|
||||
****************************************************************************/
|
||||
|
||||
static void i2c_bb_ioe_init(FAR struct i2c_bitbang_lower_dev_s *lower);
|
||||
static void i2c_bb_ioe_set_scl(FAR struct i2c_bitbang_lower_dev_s *lower,
|
||||
bool value);
|
||||
static void i2c_bb_ioe_set_sda(FAR struct i2c_bitbang_lower_dev_s *lower,
|
||||
bool value);
|
||||
static bool i2c_bb_ioe_get_scl(FAR struct i2c_bitbang_lower_dev_s *lower);
|
||||
static bool i2c_bb_ioe_get_sda(FAR struct i2c_bitbang_lower_dev_s *lower);
|
||||
|
||||
/****************************************************************************
|
||||
* Private Data
|
||||
****************************************************************************/
|
||||
|
||||
/* Lower-half I2C bitbang data */
|
||||
|
||||
const static struct i2c_bitbang_lower_ops_s g_i2c_bitbang_ops =
|
||||
{
|
||||
.initialize = i2c_bb_ioe_init,
|
||||
.set_scl = i2c_bb_ioe_set_scl,
|
||||
.set_sda = i2c_bb_ioe_set_sda,
|
||||
.get_scl = i2c_bb_ioe_get_scl,
|
||||
.get_sda = i2c_bb_ioe_get_sda
|
||||
};
|
||||
|
||||
/****************************************************************************
|
||||
* Private Functions
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bb_ioe_init
|
||||
*
|
||||
* Description:
|
||||
* Initialize the I2C bit-bang driver
|
||||
*
|
||||
* Input Parameters:
|
||||
* lower - A pointer the publicly visible representation of
|
||||
* the "lower-half" driver state structure.
|
||||
*
|
||||
* Returned Value:
|
||||
* None
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
static void i2c_bb_ioe_init(FAR struct i2c_bitbang_lower_dev_s *lower)
|
||||
{
|
||||
FAR struct i2c_bb_ioe_s *dev = lower->priv;
|
||||
|
||||
IOEXP_WRITEPIN(dev->ioe, dev->scl_pin, 1);
|
||||
IOEXP_WRITEPIN(dev->ioe, dev->sda_pin, 1);
|
||||
|
||||
IOEXP_SETDIRECTION(dev->ioe, dev->scl_pin,
|
||||
IOEXPANDER_DIRECTION_OUT_OPENDRAIN);
|
||||
IOEXP_SETDIRECTION(dev->ioe, dev->sda_pin,
|
||||
IOEXPANDER_DIRECTION_OUT_OPENDRAIN);
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bb_ioe_set_scl
|
||||
*
|
||||
* Description:
|
||||
* Set SCL line value
|
||||
*
|
||||
* Input Parameters:
|
||||
* lower - A pointer the publicly visible representation of
|
||||
* the "lower-half" driver state structure.
|
||||
* value - The value to be written (0 or 1).
|
||||
*
|
||||
* Returned Value:
|
||||
* None
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
static void i2c_bb_ioe_set_scl(FAR struct i2c_bitbang_lower_dev_s *lower,
|
||||
bool value)
|
||||
{
|
||||
FAR struct i2c_bb_ioe_s *dev = lower->priv;
|
||||
|
||||
IOEXP_WRITEPIN(dev->ioe, dev->scl_pin, value);
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bb_ioe_set_sda
|
||||
*
|
||||
* Description:
|
||||
* Set SDA line value
|
||||
*
|
||||
* Input Parameters:
|
||||
* lower - A pointer the publicly visible representation of
|
||||
* the "lower-half" driver state structure.
|
||||
* value - The value to be written (0 or 1).
|
||||
*
|
||||
* Returned Value:
|
||||
* None
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
static void i2c_bb_ioe_set_sda(FAR struct i2c_bitbang_lower_dev_s *lower,
|
||||
bool value)
|
||||
{
|
||||
FAR struct i2c_bb_ioe_s *dev = lower->priv;
|
||||
|
||||
IOEXP_WRITEPIN(dev->ioe, dev->sda_pin, value);
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bb_ioe_get_scl
|
||||
*
|
||||
* Description:
|
||||
* Get value from SCL line
|
||||
*
|
||||
* Input Parameters:
|
||||
* lower - A pointer the publicly visible representation of
|
||||
* the "lower-half" driver state structure.
|
||||
*
|
||||
* Returned Value:
|
||||
* The boolean representation of the SCL line value (true/false).
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
static bool i2c_bb_ioe_get_scl(FAR struct i2c_bitbang_lower_dev_s *lower)
|
||||
{
|
||||
FAR struct i2c_bb_ioe_s *dev = lower->priv;
|
||||
bool value = true;
|
||||
int ret;
|
||||
|
||||
ret = IOEXP_READPIN(dev->ioe, dev->scl_pin, &value);
|
||||
if (ret < 0)
|
||||
{
|
||||
i2cerr("read scl pin:%d, error res:%d\n", dev->scl_pin, ret);
|
||||
}
|
||||
|
||||
return value;
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bb_ioe_get_sda
|
||||
*
|
||||
* Description:
|
||||
* Get value from SDA line
|
||||
*
|
||||
* Input Parameters:
|
||||
* lower - A pointer the publicly visible representation of
|
||||
* the "lower-half" driver state structure.
|
||||
*
|
||||
* Returned Value:
|
||||
* The boolean representation of the SDA line value (true/false).
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
static bool i2c_bb_ioe_get_sda(FAR struct i2c_bitbang_lower_dev_s *lower)
|
||||
{
|
||||
FAR struct i2c_bb_ioe_s *dev = lower->priv;
|
||||
bool value = true;
|
||||
int ret;
|
||||
|
||||
ret = IOEXP_READPIN(dev->ioe, dev->sda_pin, &value);
|
||||
if (ret < 0)
|
||||
{
|
||||
i2cerr("read sda pin:%d, error res:%d\n", dev->sda_pin, ret);
|
||||
}
|
||||
|
||||
return value;
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Public Functions
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bitbang_ioexpander_initialize
|
||||
*
|
||||
* Description:
|
||||
* Initialize i2c bitbang ioexapnder lower half driver.
|
||||
*
|
||||
* Input Parameters:
|
||||
* ioe - An instance of the ioexpander device to use for bitbanging
|
||||
* scl_pin - The pin number to use for SCL
|
||||
* sda_pin - The pin number to use for SDA
|
||||
* busnum - The I2C bus number to register
|
||||
*
|
||||
* Returned Value:
|
||||
* On success, a pointer to the initialized I2C driver for the specified.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
FAR struct i2c_master_s *
|
||||
i2c_bitbang_ioexpander_initialize(FAR struct ioexpander_dev_s *ioe,
|
||||
int scl_pin, int sda_pin, int busnum)
|
||||
{
|
||||
FAR struct i2c_master_s *master = NULL;
|
||||
FAR struct i2c_bb_ioe_s *priv;
|
||||
|
||||
priv = kmm_zalloc(sizeof(struct i2c_bb_ioe_s));
|
||||
if (priv == NULL)
|
||||
{
|
||||
i2cerr("i2c-bitbang%d kmm_zalloc failed\n", busnum);
|
||||
return master;
|
||||
}
|
||||
|
||||
priv->lower.priv = priv;
|
||||
priv->lower.ops = &g_i2c_bitbang_ops;
|
||||
priv->scl_pin = scl_pin;
|
||||
priv->sda_pin = sda_pin;
|
||||
priv->ioe = ioe;
|
||||
|
||||
master = i2c_bitbang_initialize(&priv->lower);
|
||||
if (master == NULL)
|
||||
{
|
||||
kmm_free(priv);
|
||||
i2cerr("I2c bitbang:%d initialize failed\n", busnum);
|
||||
return master;
|
||||
}
|
||||
|
||||
if (busnum >= 0)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = i2c_register(master, busnum);
|
||||
if (ret < 0)
|
||||
{
|
||||
kmm_free(priv);
|
||||
kmm_free(master);
|
||||
master = NULL;
|
||||
i2cerr("I2c bitbang:%d register failed:%d\n", busnum, ret);
|
||||
}
|
||||
}
|
||||
|
||||
return master;
|
||||
}
|
||||
@@ -0,0 +1,60 @@
|
||||
/****************************************************************************
|
||||
* include/nuttx/i2c/i2c_bitbang_ioexpander.h
|
||||
*
|
||||
* Licensed to the Apache Software Foundation (ASF) under one or more
|
||||
* contributor license agreements. See the NOTICE file distributed with
|
||||
* this work for additional information regarding copyright ownership. The
|
||||
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
||||
* "License"); you may not use this file except in compliance with the
|
||||
* License. You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing, software
|
||||
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||
* License for the specific language governing permissions and limitations
|
||||
* under the License.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
#ifndef __INCLUDE_NUTTX_I2C_I2C_BITBANG_IOEXPANDER_H
|
||||
#define __INCLUDE_NUTTX_I2C_I2C_BITBANG_IOEXPANDER_H
|
||||
|
||||
/****************************************************************************
|
||||
* Included Files
|
||||
****************************************************************************/
|
||||
|
||||
#include <nuttx/i2c/i2c_master.h>
|
||||
#include <nuttx/ioexpander/ioexpander.h>
|
||||
|
||||
/****************************************************************************
|
||||
* Public Type Definitions
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Pre-processor Definitions
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Name: i2c_bitbang_ioexpander_initialize
|
||||
*
|
||||
* Description:
|
||||
* Initialize i2c bitbang ioexapnder lower half driver.
|
||||
*
|
||||
* Input Parameters:
|
||||
* ioe - An instance of the ioexpander device to use for bitbanging
|
||||
* scl_pin - The pin number to use for SCL
|
||||
* sda_pin - The pin number to use for SDA
|
||||
* busnum - The I2C bus number to register
|
||||
*
|
||||
* Returned Value:
|
||||
* On success, a pointer to the initialized I2C driver for the specified.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
FAR struct i2c_master_s *
|
||||
i2c_bitbang_ioexpander_initialize(FAR struct ioexpander_dev_s *ioe,
|
||||
int scl_pin, int sda_pin, int busnum);
|
||||
|
||||
#endif /* __INCLUDE_NUTTX_I2C_I2C_BITBANG_IOEXPANDER_H */
|
||||
Reference in New Issue
Block a user