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[dev/gpio_i2c] add optional pullups

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If GPIO_I2C_PULLUPS == 1, enables pullups when not actively
driving I2C lines low.
This commit is contained in:
Girts Folkmanis
2016-09-30 10:07:16 -07:00
committed by Travis Geiselbrecht
parent 5e7df94fdd
commit a74d56b9a2
2 changed files with 31 additions and 13 deletions
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32
dev/gpio_i2c/gpio_i2c.c
View File

@@ -35,6 +35,12 @@
#error ERROR: Must define GPIO_I2C_BUS_COUNT
#endif
#if GPIO_I2C_PULLUPS
#define GPIO_I2C_INPUT (GPIO_INPUT | GPIO_PULLUP)
#else
#define GPIO_I2C_INPUT (GPIO_INPUT)
#endif // GPIO_I2C_PULLUPS
typedef struct gpio_i2c_state {
mutex_t lock;
const gpio_i2c_info_t *info;
@@ -58,14 +64,14 @@ static inline void send_start(const gpio_i2c_info_t *i)
static inline void send_stop(const gpio_i2c_info_t *i)
{
gpio_config(i->sda, GPIO_OUTPUT);
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->qcd);
gpio_config(i->sda, GPIO_INPUT);
gpio_config(i->sda, GPIO_I2C_INPUT);
}
static inline void send_restart(const gpio_i2c_info_t *i)
{
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->qcd);
send_start(i);
}
@@ -73,10 +79,10 @@ static inline void send_restart(const gpio_i2c_info_t *i)
static inline void send_nack(const gpio_i2c_info_t *i)
{
spin_cycles(i->hcd);
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->hcd);
gpio_config(i->scl, GPIO_OUTPUT);
gpio_config(i->sda, GPIO_INPUT);
gpio_config(i->sda, GPIO_I2C_INPUT);
}
static inline void send_ack(const gpio_i2c_info_t *i)
@@ -91,7 +97,7 @@ static inline bool send_byte(const gpio_i2c_info_t *i, uint32_t b)
for (size_t j = 0; j < 8; ++j) {
if (b & 0x80)
gpio_config(i->sda, GPIO_INPUT);
gpio_config(i->sda, GPIO_I2C_INPUT);
else
gpio_config(i->sda, GPIO_OUTPUT);
b <<= 1;
@@ -102,14 +108,14 @@ static inline bool send_byte(const gpio_i2c_info_t *i, uint32_t b)
* right here.
*/
spin_cycles(i->hcd);
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->hcd);
gpio_config(i->scl, GPIO_OUTPUT);
}
gpio_config(i->sda, GPIO_INPUT);
gpio_config(i->sda, GPIO_I2C_INPUT);
spin_cycles(i->hcd);
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->hcd);
ret = (0 == gpio_get(i->sda));
gpio_config(i->scl, GPIO_OUTPUT);
@@ -123,7 +129,7 @@ static inline void recv_byte(const gpio_i2c_info_t *i, uint8_t *b)
uint32_t tmp = 0;
for (size_t j = 0; j < 7; ++j) {
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->hcd);
if (gpio_get(i->sda))
tmp |= 1;
@@ -132,7 +138,7 @@ static inline void recv_byte(const gpio_i2c_info_t *i, uint8_t *b)
spin_cycles(i->hcd);
}
gpio_config(i->scl, GPIO_INPUT);
gpio_config(i->scl, GPIO_I2C_INPUT);
spin_cycles(i->hcd);
if (gpio_get(i->sda))
tmp |= 1;
@@ -222,8 +228,8 @@ void gpio_i2c_add_bus(uint32_t bus_id, const gpio_i2c_info_t *info)
DEBUG_ASSERT(bus_id < GPIO_I2C_BUS_COUNT);
DEBUG_ASSERT(!s->info);
gpio_config(info->scl, GPIO_INPUT);
gpio_config(info->sda, GPIO_INPUT);
gpio_config(info->scl, GPIO_I2C_INPUT);
gpio_config(info->sda, GPIO_I2C_INPUT);
gpio_set(info->scl, 0);
gpio_set(info->sda, 0);

12
dev/gpio_i2c/rules.mk
View File

@@ -1,3 +1,10 @@
# I2C bit-banging using GPIO lines.
#
# Before including the module, define:
#
# GPIO_I2C_BUS_COUNT: number of SDA/SCL pairs to be used.
# GPIO_I2C_PULLUPS (optional): if 1, enables pullups.
LOCAL_DIR := $(GET_LOCAL_DIR)
MODULE := $(LOCAL_DIR)
@@ -8,4 +15,9 @@ MODULE_SRCS := \
MODULE_DEFINES += \
GPIO_I2C_BUS_COUNT=$(GPIO_I2C_BUS_COUNT)
ifneq ($(GPIO_I2C_PULLUPS),)
MODULE_DEFINES += \
GPIO_I2C_PULLUPS=$(GPIO_I2C_PULLUPS)
endif
include make/module.mk