I2C sw driver with support of multiple buses, Slow, Fast, FastPlus, and user-defined speed selection

app/include/driver/i2c_master.h

@@ -1,74 +1,12 @@
 #ifndef __I2C_MASTER_H__
 #define __I2C_MASTER_H__
 
-#define I2C_MASTER_SDA_MUX (pin_mux[sda])
-#define I2C_MASTER_SCL_MUX (pin_mux[scl])
-#define I2C_MASTER_SDA_GPIO (pinSDA)
-#define I2C_MASTER_SCL_GPIO (pinSCL)
-#define I2C_MASTER_SDA_FUNC (pin_func[sda])
-#define I2C_MASTER_SCL_FUNC (pin_func[scl])
-
-// #define I2C_MASTER_SDA_MUX PERIPHS_IO_MUX_GPIO2_U
-// #define I2C_MASTER_SCL_MUX PERIPHS_IO_MUX_MTDO_U
-// #define I2C_MASTER_SDA_GPIO 2
-// #define I2C_MASTER_SCL_GPIO 15
-// #define I2C_MASTER_SDA_FUNC FUNC_GPIO2
-// #define I2C_MASTER_SCL_FUNC FUNC_GPIO15
-
-// #define I2C_MASTER_SDA_MUX PERIPHS_IO_MUX_GPIO2_U
-// #define I2C_MASTER_SCL_MUX PERIPHS_IO_MUX_MTMS_U
-// #define I2C_MASTER_SDA_GPIO 2
-// #define I2C_MASTER_SCL_GPIO 14
-// #define I2C_MASTER_SDA_FUNC FUNC_GPIO2
-// #define I2C_MASTER_SCL_FUNC FUNC_GPIO14
-
-//#define I2C_MASTER_SDA_MUX PERIPHS_IO_MUX_GPIO2_U
-//#define I2C_MASTER_SCL_MUX PERIPHS_IO_MUX_GPIO0_U
-//#define I2C_MASTER_SDA_GPIO 2
-//#define I2C_MASTER_SCL_GPIO 0
-//#define I2C_MASTER_SDA_FUNC FUNC_GPIO2
-//#define I2C_MASTER_SCL_FUNC FUNC_GPIO0
-
-#if 0
-#define I2C_MASTER_GPIO_SET(pin)  \
-    gpio_output_set(1<<pin,0,1<<pin,0)
-
-#define I2C_MASTER_GPIO_CLR(pin) \
-    gpio_output_set(0,1<<pin,1<<pin,0)
-
-#define I2C_MASTER_GPIO_OUT(pin,val) \
-    if(val) I2C_MASTER_GPIO_SET(pin);\
-    else I2C_MASTER_GPIO_CLR(pin)
-#endif
-
-#define I2C_MASTER_SDA_HIGH_SCL_HIGH()  \
-    gpio_output_set(1<<I2C_MASTER_SDA_GPIO | 1<<I2C_MASTER_SCL_GPIO, 0, 1<<I2C_MASTER_SDA_GPIO | 1<<I2C_MASTER_SCL_GPIO, 0)
-
-#define I2C_MASTER_SDA_HIGH_SCL_LOW()  \
-    gpio_output_set(1<<I2C_MASTER_SDA_GPIO, 1<<I2C_MASTER_SCL_GPIO, 1<<I2C_MASTER_SDA_GPIO | 1<<I2C_MASTER_SCL_GPIO, 0)
-
-#define I2C_MASTER_SDA_LOW_SCL_HIGH()  \
-    gpio_output_set(1<<I2C_MASTER_SCL_GPIO, 1<<I2C_MASTER_SDA_GPIO, 1<<I2C_MASTER_SDA_GPIO | 1<<I2C_MASTER_SCL_GPIO, 0)
-
-#define I2C_MASTER_SDA_LOW_SCL_LOW()  \
-    gpio_output_set(0, 1<<I2C_MASTER_SDA_GPIO | 1<<I2C_MASTER_SCL_GPIO, 1<<I2C_MASTER_SDA_GPIO | 1<<I2C_MASTER_SCL_GPIO, 0)
-
-void i2c_master_gpio_init(uint8 sda, uint8 scl);
-void i2c_master_init(void);
-
-#define i2c_master_wait    os_delay_us
-void i2c_master_stop(void);
-void i2c_master_start(void);
-void i2c_master_setAck(uint8 level);
-uint8 i2c_master_getAck(void);
-uint8 i2c_master_readByte(void);
-void i2c_master_writeByte(uint8 wrdata);
-
-bool i2c_master_checkAck(void);
-void i2c_master_send_ack(void);
-void i2c_master_send_nack(void);
-
-uint8 i2c_master_get_pinSDA();
-uint8 i2c_master_get_pinSCL();
-
-#endif
+uint32 i2c_master_setup(uint16 id, uint8 sda, uint8 scl, uint32 speed);
+void i2c_master_init(uint16 id);
+bool i2c_master_configured(uint16 id);
+void i2c_master_stop(uint16 id);
+void i2c_master_start(uint16 id);
+uint8 i2c_master_readByte(uint16 id, sint16 ack);
+uint8 i2c_master_writeByte(uint16 id, uint8 wrdata);
+
+#endif //__I2C_MASTER_H__

app/include/user_config.h

@@ -156,6 +156,22 @@
 #define ENDUSER_SETUP_AP_SSID "SetupGadget"
 
 
+// I2C software driver partially supports use of GPIO16 (D0) pin for SCL line.
+// GPIO16 does not support open-drain mode and works in push-pull mode,
+// so clock stretching will not be possible, because circuit in slave device that
+// supposed to drive SCL low during stretching will not be capable to hold SCL low.
+// Also I2C speed will be limited to no more than 400000 Hz (FAST mode).
+// This define is does not have an effect on an old driver (see I2C_MASTER_OLD_VERSION).
+
+//#define I2C_MASTER_GPIO16_ENABLE
+
+// For compatibility reasons you can switch to old version of I2C software driver.
+// It does not support changing speed, have only one bus id = 0, does not support GPIO16
+// and works only in Standard(slow) mode with clock speed around 50kHz.
+
+#define I2C_MASTER_OLD_VERSION
+
+
 // The following sections are only relevent for those developers who are
 // developing modules or core Lua changes and configure how extra diagnostics
 // are enabled in the firmware. These should only be configured if you are

app/modules/i2c.c

@@ -15,13 +15,16 @@ static int i2c_setup( lua_State *L )
   MOD_CHECK_ID( gpio, sda );
   MOD_CHECK_ID( gpio, scl );
 
-  if(scl==0 || sda==0)
-    return luaL_error( L, "no i2c for D0" );
+  if ( sda == 0 )
+    return luaL_error( L, "i2c SDA on D0 is not supported" );
 
   s32 speed = ( s32 )luaL_checkinteger( L, 4 );
-  if (speed <= 0)
+  if ( speed <= 0 )
     return luaL_error( L, "wrong arg range" );
-  lua_pushinteger( L, platform_i2c_setup( id, sda, scl, (u32)speed ) );
+  speed = platform_i2c_setup( id, sda, scl, (u32)speed );
+  if ( speed == 0 )
+    return luaL_error( L, "failed to initialize i2c %d", id );
+  lua_pushinteger( L, speed );
   return 1;
 }
 
@@ -31,7 +34,10 @@ static int i2c_start( lua_State *L )
   unsigned id = luaL_checkinteger( L, 1 );
 
   MOD_CHECK_ID( i2c, id );
-  platform_i2c_send_start( id );
+  if (platform_i2c_configured( id ) )
+      platform_i2c_send_start( id );
+  else
+      luaL_error( L, "i2c %d is not configured", id );
   return 0;
 }
 
@@ -147,7 +153,8 @@ static const LUA_REG_TYPE i2c_map[] = {
   { LSTRKEY( "address" ),     LFUNCVAL( i2c_address ) },
   { LSTRKEY( "write" ),       LFUNCVAL( i2c_write ) },
   { LSTRKEY( "read" ),        LFUNCVAL( i2c_read ) },
- //{ LSTRKEY( "FAST" ),       LNUMVAL( PLATFORM_I2C_SPEED_FAST ) },
+  { LSTRKEY( "FASTPLUS" ),    LNUMVAL( PLATFORM_I2C_SPEED_FASTPLUS ) },
+  { LSTRKEY( "FAST" ),        LNUMVAL( PLATFORM_I2C_SPEED_FAST ) },
   { LSTRKEY( "SLOW" ),        LNUMVAL( PLATFORM_I2C_SPEED_SLOW ) },
   { LSTRKEY( "TRANSMITTER" ), LNUMVAL( PLATFORM_I2C_DIRECTION_TRANSMITTER ) },
   { LSTRKEY( "RECEIVER" ),    LNUMVAL( PLATFORM_I2C_DIRECTION_RECEIVER ) },

app/platform/cpu_esp8266.h

@@ -15,7 +15,13 @@
 #define NUM_PWM               GPIO_PIN_NUM
 #define NUM_ADC               1
 #define NUM_CAN               0
+
+#ifndef I2C_MASTER_OLD_VERSION
+#define NUM_I2C               10
+#else
 #define NUM_I2C               1
+#endif //I2C_MASTER_OLD_VERSION
+
 #define NUM_OW                GPIO_PIN_NUM
 #define NUM_TMR               7
 

app/platform/platform.c

@@ -735,16 +735,19 @@ uint32_t platform_i2c_setup( unsigned id, uint8_t sda, uint8_t scl, uint32_t spe
   platform_gpio_mode(sda, PLATFORM_GPIO_INPUT, PLATFORM_GPIO_PULLUP);   // inside this func call platform_pwm_close
   platform_gpio_mode(scl, PLATFORM_GPIO_INPUT, PLATFORM_GPIO_PULLUP);    // disable gpio interrupt first
 
-  i2c_master_gpio_init(sda, scl);
-  return PLATFORM_I2C_SPEED_SLOW;
+  return i2c_master_setup(id, sda, scl, speed);
+}
+
+bool platform_i2c_configured( unsigned id ){
+  return i2c_master_configured(id);
 }
 
 void platform_i2c_send_start( unsigned id ){
-  i2c_master_start();
+  i2c_master_start(id);
 }
 
 void platform_i2c_send_stop( unsigned id ){
-  i2c_master_stop();
+  i2c_master_stop(id);
 }
 
 int platform_i2c_send_address( unsigned id, uint16_t address, int direction ){
@@ -754,22 +757,17 @@ int platform_i2c_send_address( unsigned id, uint16_t address, int direction ){
            PLATFORM_I2C_DIRECTION_RECEIVER == 1 ) ) {
     direction = ( direction == PLATFORM_I2C_DIRECTION_TRANSMITTER ) ? 0 : 1;
   }
-
-  i2c_master_writeByte( (uint8_t) ((address << 1) | direction ));
-  // Low-level returns nack (0=acked); we return ack (1=acked).
-  return ! i2c_master_getAck();
+  return i2c_master_writeByte(id,
+    (uint8_t) ((address << 1) + (direction == PLATFORM_I2C_DIRECTION_TRANSMITTER ? 0 : 1))
+  );
 }
 
-int platform_i2c_send_byte( unsigned id, uint8_t data ){
-  i2c_master_writeByte(data);
-  // Low-level returns nack (0=acked); we return ack (1=acked).
-  return ! i2c_master_getAck();
+int platform_i2c_send_byte(unsigned id, uint8_t data ){
+  return i2c_master_writeByte(id, data);
 }
 
 int platform_i2c_recv_byte( unsigned id, int ack ){
-  uint8_t r = i2c_master_readByte();
-  i2c_master_setAck( !ack );
-  return r;
+  return i2c_master_readByte(id, ack);
 }
 
 // *****************************************************************************

app/platform/platform.h

@@ -235,7 +235,8 @@ void platform_sigma_delta_set_target( uint8_t target );
 enum
 {
   PLATFORM_I2C_SPEED_SLOW = 100000,
-  PLATFORM_I2C_SPEED_FAST = 400000
+  PLATFORM_I2C_SPEED_FAST = 400000,
+  PLATFORM_I2C_SPEED_FASTPLUS = 1000000
 };
 
 // I2C direction
@@ -251,6 +252,7 @@ static inline int platform_i2c_exists( unsigned id ) { return id < NUM_I2C; }
 static inline int platform_i2c_exists( unsigned id ) { return 0; }
 #endif
 uint32_t platform_i2c_setup( unsigned id, uint8_t sda, uint8_t scl, uint32_t speed );
+bool platform_i2c_configured( unsigned id );
 void platform_i2c_send_start( unsigned id );
 void platform_i2c_send_stop( unsigned id );
 int platform_i2c_send_address( unsigned id, uint16_t address, int direction );