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drivers: i2c: gpio: convert to using devicetree for instances
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Convert the GPIO bit banging I2C controller driver to use devicetree
bindings for configuring instances.

Signed-off-by: Henrik Brix Andersen <[email protected]>
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@henrikbrixandersen @galak
henrikbrixandersen authored and galak committed May 5, 2020
1 parent ea61a6e commit 911b6a0
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Showing 2 changed files with 68 additions and 173 deletions.
140 changes: 0 additions & 140 deletions drivers/i2c/Kconfig.gpio
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,143 +6,3 @@ config I2C_GPIO
select I2C_BITBANG
help
Enable software driven (bit banging) I2C support using GPIO pins

# ---------- Port 0 ----------

config I2C_GPIO_0
bool "Enable GPIO Bit Bang I2C device 0"
depends on I2C_GPIO
help
This tells the driver to configure the I2C device at boot, depending
on the additional configuration options below.

if I2C_GPIO_0

config I2C_GPIO_0_NAME
string "GPIO Bit Bang I2C device 0 device name"
default "I2C_0"
help
This is the device name for the I2C device, and is included in the
device struct.

config I2C_GPIO_0_GPIO
string "Bit Bang I2C device 0 GPIO name"
help
This is the name of the GPIO device that controls the I2C lines.

config I2C_GPIO_0_SCL_PIN
int "Bit Bang I2C device 0 GPIO pin number for SCL"
help
This is the GPIO pin number for the I2S SCL line

config I2C_GPIO_0_SDA_PIN
int "Bit Bang I2C device 0 GPIO pin number for SDA"
help
This is the GPIO pin number for the I2S SDA line

endif # I2C_GPIO_0

# ---------- Port 1 ----------

config I2C_GPIO_1
bool "Enable GPIO Bit Bang I2C device 1"
depends on I2C_GPIO
help
This tells the driver to configure the I2C device at boot, depending
on the additional configuration options below.

if I2C_GPIO_1

config I2C_GPIO_1_NAME
string "Bit Bang I2C device 1 device name"
default "I2C_1"
help
This is the device name for the I2C device, and is included in the
device struct.

config I2C_GPIO_1_GPIO
string "Bit Bang I2C device 1 GPIO name"
help
This is the name of the GPIO device that controls the I2C lines.

config I2C_GPIO_1_SCL_PIN
int "Bit Bang I2C device 1 GPIO pin number for SCL"
help
This is the GPIO pin number for the I2S SCL line

config I2C_GPIO_1_SDA_PIN
int "Bit Bang I2C device 1 GPIO pin number for SDA"
help
This is the GPIO pin number for the I2S SDA line

endif # I2C_GPIO_1

# ---------- Port 2 ----------

config I2C_GPIO_2
bool "Enable GPIO Bit Bang I2C device 2"
depends on I2C_GPIO
help
This tells the driver to configure the I2C device at boot, depending
on the additional configuration options below.

if I2C_GPIO_2

config I2C_GPIO_2_NAME
string "Bit Bang I2C device 2 device name"
default "I2C_2"
help
This is the device name for the I2C device, and is included in the
device struct.

config I2C_GPIO_2_GPIO
string "Bit Bang I2C device 2 GPIO name"
help
This is the name of the GPIO device that controls the I2C lines.

config I2C_GPIO_2_SCL_PIN
int "Bit Bang I2C device 2 GPIO pin number for SCL"
help
This is the GPIO pin number for the I2S SCL line

config I2C_GPIO_2_SDA_PIN
int "Bit Bang I2C device 2 GPIO pin number for SDA"
help
This is the GPIO pin number for the I2S SDA line

endif # I2C_GPIO_2

# ---------- Port 3 ----------

config I2C_GPIO_3
bool "Enable GPIO Bit Bang I2C device 3"
depends on I2C_GPIO
help
This tells the driver to configure the I2C device at boot, depending
on the additional configuration options below.

if I2C_GPIO_3

config I2C_GPIO_3_NAME
string "Bit Bang I2C device 3 device name"
default "I2C_3"
help
This is the device name for the I2C device, and is included in the
device struct.

config I2C_GPIO_3_GPIO
string "Bit Bang I2C device 3 GPIO name"
help
This is the name of the GPIO device that controls the I2C lines.

config I2C_GPIO_3_SCL_PIN
int "Bit Bang I2C device 3 GPIO pin number for SCL"
help
This is the GPIO pin number for the I2C SCL line

config I2C_GPIO_3_SDA_PIN
int "Bit Bang I2C device 3 GPIO pin number for SDA"
help
This is the GPIO pin number for the I2C SDA line

endif # I2C_GPIO_3
101 changes: 68 additions & 33 deletions drivers/i2c/i2c_gpio.c
View file
Original file line number Diff line number Diff line change
@@ -1,16 +1,19 @@
/*
* Copyright (c) 2020 Vestas Wind Systems A/S
* Copyright (c) 2017 Linaro Ltd.
*
* SPDX-License-Identifier: Apache-2.0
*/

#define DT_DRV_COMPAT gpio_i2c

/**
* @file
* @brief Driver for software driven I2C using GPIO lines
*
* This driver implements an I2C interface by driving two GPIO lines under
* software control. The GPIO pins used must be preconfigured to to a suitable
* state, i.e. the SDA pin as open-colector/open-drain with a pull-up resistor
* software control. The GPIO pins used must be configured (through devicetree and pinmux) with suitable
* flags, i.e. the SDA pin as open-colector/open-drain with a pull-up resistor
* (possibly as an external component attached to the pin). When the SDA pin
* is read it must return the state of the physical hardware line, not just the
* last state written to it for output.
Expand All @@ -24,41 +27,51 @@
#include <errno.h>
#include <drivers/gpio.h>
#include <drivers/i2c.h>

#include <logging/log.h>
LOG_MODULE_REGISTER(i2c_gpio);

#include "i2c-priv.h"
#include "i2c_bitbang.h"

/* Driver config */
struct i2c_gpio_config {
char *gpio_name;
u8_t scl_pin;
u8_t sda_pin;
const char *scl_gpio_name;
const char *sda_gpio_name;
gpio_pin_t scl_pin;
gpio_pin_t sda_pin;
gpio_dt_flags_t scl_flags;
gpio_dt_flags_t sda_flags;
u32_t bitrate;
};

/* Driver instance data */
struct i2c_gpio_context {
struct i2c_bitbang bitbang; /* Bit-bang library data */
struct device *gpio; /* GPIO used for I2C lines */
u8_t scl_pin; /* Pin on gpio used for SCL line */
u8_t sda_pin; /* Pin on gpio used for SDA line */
struct device *scl_gpio; /* GPIO used for I2C SCL line */
struct device *sda_gpio; /* GPIO used for I2C SDA line */
gpio_pin_t scl_pin; /* Pin on gpio used for SCL line */
gpio_pin_t sda_pin; /* Pin on gpio used for SDA line */
};

static void i2c_gpio_set_scl(void *io_context, int state)
{
struct i2c_gpio_context *context = io_context;

gpio_pin_set(context->gpio, context->scl_pin, state);
gpio_pin_set(context->scl_gpio, context->scl_pin, state);
}

static void i2c_gpio_set_sda(void *io_context, int state)
{
struct i2c_gpio_context *context = io_context;

gpio_pin_set(context->gpio, context->sda_pin, state);
gpio_pin_set(context->sda_gpio, context->sda_pin, state);
}

static int i2c_gpio_get_sda(void *io_context)
{
struct i2c_gpio_context *context = io_context;
int rc = gpio_pin_get(context->gpio, context->sda_pin);
int rc = gpio_pin_get(context->sda_gpio, context->sda_pin);

/* Default high as that would be a NACK */
return rc != 0;
Expand All @@ -83,7 +96,7 @@ static int i2c_gpio_transfer(struct device *dev, struct i2c_msg *msgs,
struct i2c_gpio_context *context = dev->driver_data;

return i2c_bitbang_transfer(&context->bitbang, msgs, num_msgs,
slave_address);
slave_address);
}

static struct i2c_driver_api api = {
Expand All @@ -95,16 +108,48 @@ static int i2c_gpio_init(struct device *dev)
{
struct i2c_gpio_context *context = dev->driver_data;
const struct i2c_gpio_config *config = dev->config->config_info;
u32_t bitrate_cfg;
int err;

context->scl_gpio = device_get_binding(config->scl_gpio_name);
if (!context->scl_gpio) {
LOG_ERR("failed to get SCL GPIO device");
return -EINVAL;
}

err = gpio_config(context->scl_gpio, config->scl_pin,
config->scl_flags | GPIO_OUTPUT_HIGH);
if (err) {
LOG_ERR("failed to configure SCL GPIO pin (err %d)", err);
return err;
}

context->gpio = device_get_binding(config->gpio_name);
if (!context->gpio) {
context->sda_gpio = device_get_binding(config->sda_gpio_name);
if (!context->sda_gpio) {
LOG_ERR("failed to get SCL GPIO device");
return -EINVAL;
}

err = gpio_config(context->sda_gpio, config->sda_pin,
config->sda_flags | GPIO_OUTPUT_HIGH);
if (err) {
LOG_ERR("failed to configure SDA GPIO pin (err %d)", err);
return err;
}

context->sda_pin = config->sda_pin;
context->scl_pin = config->scl_pin;

i2c_bitbang_init(&context->bitbang, &io_fns, context);

bitrate_cfg = i2c_map_dt_bitrate(config->bitrate);
err = i2c_bitbang_configure(&context->bitbang,
I2C_MODE_MASTER | bitrate_cfg);
if (err) {
LOG_ERR("failed to configure I2C bitbang (err %d)", err);
return err;
}

return 0;
}

Expand All @@ -113,29 +158,19 @@ static int i2c_gpio_init(struct device *dev)
static struct i2c_gpio_context i2c_gpio_dev_data_##_num; \
\
static const struct i2c_gpio_config i2c_gpio_dev_cfg_##_num = { \
.gpio_name = CONFIG_I2C_GPIO_##_num##_GPIO, \
.scl_pin = CONFIG_I2C_GPIO_##_num##_SCL_PIN, \
.sda_pin = CONFIG_I2C_GPIO_##_num##_SDA_PIN, \
.scl_gpio_name = DT_INST_GPIO_LABEL(_num, scl_gpios), \
.sda_gpio_name = DT_INST_GPIO_LABEL(_num, sda_gpios), \
.scl_pin = DT_INST_GPIO_PIN(_num, scl_gpios), \
.sda_pin = DT_INST_GPIO_PIN(_num, sda_gpios), \
.scl_flags = DT_INST_GPIO_FLAGS(_num, scl_gpios), \
.sda_flags = DT_INST_GPIO_FLAGS(_num, sda_gpios), \
.bitrate = DT_INST_PROP(_num, clock_frequency), \
}; \
\
DEVICE_AND_API_INIT(i2c_gpio_##_num, CONFIG_I2C_GPIO_##_num##_NAME, \
DEVICE_AND_API_INIT(i2c_gpio_##_num, DT_INST_LABEL(_num), \
i2c_gpio_init, \
&i2c_gpio_dev_data_##_num, \
&i2c_gpio_dev_cfg_##_num, \
PRE_KERNEL_2, CONFIG_I2C_INIT_PRIORITY, &api)

#ifdef CONFIG_I2C_GPIO_0
DEFINE_I2C_GPIO(0);
#endif

#ifdef CONFIG_I2C_GPIO_1
DEFINE_I2C_GPIO(1);
#endif

#ifdef CONFIG_I2C_GPIO_2
DEFINE_I2C_GPIO(2);
#endif

#ifdef CONFIG_I2C_GPIO_3
DEFINE_I2C_GPIO(3);
#endif
DT_INST_FOREACH(DEFINE_I2C_GPIO)

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