From baf9dd6a8275160fdf5a4ff63efa2678f16b1cc3 Mon Sep 17 00:00:00 2001
From: Marti Bolivar <mbolivar@leaflabs.com>
Date: Thu, 21 Jun 2012 15:04:39 -0400
Subject: I2C: Add i2c_config_gpios(), i2c_master_release_bus().

These are necessary to pull out some calls to gpio_set_mode().

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
---
 libmaple/i2c.c                  |  8 ++------
 libmaple/include/libmaple/i2c.h | 25 +++++++++++++++++++++++++
 libmaple/stm32f1/i2c.c          | 16 ++++++++++++++++
 3 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/libmaple/i2c.c b/libmaple/i2c.c
index 1618586..f54be47 100644
--- a/libmaple/i2c.c
+++ b/libmaple/i2c.c
@@ -299,10 +299,7 @@ void _i2c_irq_error_handler(i2c_dev *dev) {
  */
 void i2c_bus_reset(const i2c_dev *dev) {
     /* Release both lines */
-    gpio_write_bit(dev->gpio_port, dev->scl_pin, 1);
-    gpio_write_bit(dev->gpio_port, dev->sda_pin, 1);
-    gpio_set_mode(dev->gpio_port, dev->scl_pin, GPIO_OUTPUT_OD);
-    gpio_set_mode(dev->gpio_port, dev->sda_pin, GPIO_OUTPUT_OD);
+    i2c_master_release_bus(dev);
 
     /*
      * Make sure the bus is free by clocking it until any slaves release the
@@ -376,8 +373,7 @@ void i2c_master_enable(i2c_dev *dev, uint32 flags) {
 
     /* Turn on clock and set GPIO modes */
     i2c_init(dev);
-    gpio_set_mode(dev->gpio_port, dev->sda_pin, GPIO_AF_OUTPUT_OD);
-    gpio_set_mode(dev->gpio_port, dev->scl_pin, GPIO_AF_OUTPUT_OD);
+    i2c_config_gpios(dev);
 
     /* I2C1 and I2C2 are fed from APB1, clocked at 36MHz */
     i2c_set_input_clk(dev, I2C_CLK);
diff --git a/libmaple/include/libmaple/i2c.h b/libmaple/include/libmaple/i2c.h
index 9f65f13..8ce6674 100644
--- a/libmaple/include/libmaple/i2c.h
+++ b/libmaple/include/libmaple/i2c.h
@@ -288,6 +288,31 @@ static inline void i2c_disable_ack(i2c_dev *dev) {
     dev->regs->CR1 &= ~I2C_CR1_ACK;
 }
 
+/* GPIO control */
+
+/**
+ * @brief Configure device GPIOs.
+ *
+ * Configure GPIO bits dev->sda_pin and dev->scl_pin on GPIO device
+ * dev->gpio_port for use with I2C device dev.
+ *
+ * @param dev I2C Device
+ * @see i2c_release_gpios()
+ */
+extern void i2c_config_gpios(const i2c_dev *dev);
+
+/**
+ * @brief Release GPIOs controlling an I2C bus
+ *
+ * Releases the I2C bus controlled by dev as master, and disconnects
+ * GPIO bits dev->sda_pin and dev->scl_pin on GPIO device
+ * dev->gpio_port from I2C device dev.
+ *
+ * @param dev I2C device
+ * @see i2c_config_gpios()
+ */
+extern void i2c_master_release_bus(const i2c_dev *dev);
+
 /* Miscellaneous low-level routines */
 
 void i2c_init(i2c_dev *dev);
diff --git a/libmaple/stm32f1/i2c.c b/libmaple/stm32f1/i2c.c
index 9ebcb40..ed0ca97 100644
--- a/libmaple/stm32f1/i2c.c
+++ b/libmaple/stm32f1/i2c.c
@@ -39,6 +39,22 @@ i2c_dev* const I2C1 = &i2c1;
 /** STM32F1 I2C device 2 */
 i2c_dev* const I2C2 = &i2c2;
 
+/*
+ * Routines
+ */
+
+void i2c_config_gpios(const i2c_dev *dev) {
+    gpio_set_mode(dev->gpio_port, dev->sda_pin, GPIO_AF_OUTPUT_OD);
+    gpio_set_mode(dev->gpio_port, dev->scl_pin, GPIO_AF_OUTPUT_OD);
+}
+
+void i2c_master_release_bus(const i2c_dev *dev) {
+    gpio_write_bit(dev->gpio_port, dev->scl_pin, 1);
+    gpio_write_bit(dev->gpio_port, dev->sda_pin, 1);
+    gpio_set_mode(dev->gpio_port, dev->scl_pin, GPIO_OUTPUT_OD);
+    gpio_set_mode(dev->gpio_port, dev->sda_pin, GPIO_OUTPUT_OD);
+}
+
 /*
  * IRQ handlers
  */
-- 
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