I2C driver cleanup (#21273)

* remove i2c_start and i2c_stop from i2c drivers

* remove static i2c_address variable from chibios i2c driver

4 files changed, 43 insertions, 37 deletions

diff --git a/platforms/avr/drivers/i2c_master.c b/platforms/avr/drivers/i2c_master.c
index 0183103707..64083d862a 100644
--- a/platforms/avr/drivers/i2c_master.c
+++ b/platforms/avr/drivers/i2c_master.c
@@ -24,6 +24,7 @@
 #include "timer.h"
 #include "wait.h"
 #include "util.h"
+#include "progmem.h"
 
 #ifndef F_SCL
 #    define F_SCL 400000UL // SCL frequency
@@ -38,7 +39,7 @@
 
 #define TWBR_val (((F_CPU / F_SCL) - 16) / 2)
 
-void i2c_init(void) {
+__attribute__((weak)) void i2c_init(void) {
     TWSR = 0; /* no prescaler */
     TWBR = (uint8_t)TWBR_val;
 
@@ -94,7 +95,7 @@ static i2c_status_t i2c_start_impl(uint8_t address, uint16_t timeout) {
     return I2C_STATUS_SUCCESS;
 }
 
-i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
+__attribute__((always_inline)) static inline i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
     // Retry i2c_start_impl a bunch times in case the remote side has interrupts disabled.
     uint16_t     timeout_timer = timer_read();
     uint16_t     time_slice    = MAX(1, (timeout == (I2C_TIMEOUT_INFINITE)) ? 5 : (timeout / (I2C_START_RETRY_COUNT))); // if it's infinite, wait 1ms between attempts, otherwise split up the entire timeout into the number of retries
@@ -105,6 +106,11 @@ i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
     return status;
 }
 
+__attribute__((always_inline)) static inline void i2c_stop(void) {
+    // transmit STOP condition
+    TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
+}
+
 i2c_status_t i2c_write(uint8_t data, uint16_t timeout) {
     // load data into data register
     TWDR = data;
@@ -167,6 +173,18 @@ i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length,
     return status;
 }
 
+i2c_status_t i2c_transmit_P(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout) {
+    i2c_status_t status = i2c_start(address | I2C_ACTION_WRITE, timeout);
+
+    for (uint16_t i = 0; i < length && status >= 0; i++) {
+        status = i2c_write(pgm_read_byte((const char*)data++), timeout);
+    }
+
+    i2c_stop();
+
+    return status;
+}
+
 i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
     i2c_status_t status = i2c_start(address | I2C_ACTION_READ, timeout);
 
@@ -293,7 +311,8 @@ error:
     return (status < 0) ? status : I2C_STATUS_SUCCESS;
 }
 
-void i2c_stop(void) {
-    // transmit STOP condition
-    TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
-}
+__attribute__((weak)) i2c_status_t i2c_ping_address(uint8_t address, uint16_t timeout) {
+    i2c_status_t status = i2c_start(address, timeout);
+    i2c_stop();
+    return status;
+}
\ No newline at end of file
diff --git a/platforms/avr/drivers/i2c_master.h b/platforms/avr/drivers/i2c_master.h
index 18587c4a57..b797997619 100644
--- a/platforms/avr/drivers/i2c_master.h
+++ b/platforms/avr/drivers/i2c_master.h
@@ -41,14 +41,11 @@ typedef int16_t i2c_status_t;
 #define I2C_TIMEOUT_INFINITE (0xFFFF)
 
 void         i2c_init(void);
-i2c_status_t i2c_start(uint8_t address, uint16_t timeout);
-i2c_status_t i2c_write(uint8_t data, uint16_t timeout);
-int16_t      i2c_read_ack(uint16_t timeout);
-int16_t      i2c_read_nack(uint16_t timeout);
 i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout);
+i2c_status_t i2c_transmit_P(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_write_register(uint8_t devaddr, uint8_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_write_register16(uint8_t devaddr, uint16_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_read_register(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_read_register16(uint8_t devaddr, uint16_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
-void         i2c_stop(void);
+i2c_status_t i2c_ping_address(uint8_t address, uint16_t timeout);
diff --git a/platforms/chibios/drivers/i2c_master.c b/platforms/chibios/drivers/i2c_master.c
index 5ee2738e6d..ad11d850dd 100644
--- a/platforms/chibios/drivers/i2c_master.c
+++ b/platforms/chibios/drivers/i2c_master.c
@@ -1,5 +1,6 @@
 /* Copyright 2018 Jack Humbert
  * Copyright 2018 Yiancar
+ * Copyright 2023 customMK
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -90,8 +91,6 @@
 #    endif
 #endif
 
-static uint8_t i2c_address;
-
 static const I2CConfig i2cconfig = {
 #if defined(USE_I2CV1_CONTRIB)
     I2C1_CLOCK_SPEED,
@@ -125,7 +124,7 @@ static i2c_status_t i2c_epilogue(const msg_t status) {
     // From ChibiOS HAL: "After a timeout the driver must be stopped and
     // restarted because the bus is in an uncertain state." We also issue that
     // hard stop in case of any error.
-    i2c_stop();
+    i2cStop(&I2C_DRIVER);
 
     return status == MSG_TIMEOUT ? I2C_STATUS_TIMEOUT : I2C_STATUS_ERROR;
 }
@@ -150,28 +149,19 @@ __attribute__((weak)) void i2c_init(void) {
     }
 }
 
-i2c_status_t i2c_start(uint8_t address) {
-    i2c_address = address;
-    i2cStart(&I2C_DRIVER, &i2cconfig);
-    return I2C_STATUS_SUCCESS;
-}
-
 i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout) {
-    i2c_address = address;
     i2cStart(&I2C_DRIVER, &i2cconfig);
-    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), data, length, 0, 0, TIME_MS2I(timeout));
+    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (address >> 1), data, length, 0, 0, TIME_MS2I(timeout));
     return i2c_epilogue(status);
 }
 
 i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
-    i2c_address = address;
     i2cStart(&I2C_DRIVER, &i2cconfig);
-    msg_t status = i2cMasterReceiveTimeout(&I2C_DRIVER, (i2c_address >> 1), data, length, TIME_MS2I(timeout));
+    msg_t status = i2cMasterReceiveTimeout(&I2C_DRIVER, (address >> 1), data, length, TIME_MS2I(timeout));
     return i2c_epilogue(status);
 }
 
 i2c_status_t i2c_write_register(uint8_t devaddr, uint8_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout) {
-    i2c_address = devaddr;
     i2cStart(&I2C_DRIVER, &i2cconfig);
 
     uint8_t complete_packet[length + 1];
@@ -180,12 +170,11 @@ i2c_status_t i2c_write_register(uint8_t devaddr, uint8_t regaddr, const uint8_t*
     }
     complete_packet[0] = regaddr;
 
-    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), complete_packet, length + 1, 0, 0, TIME_MS2I(timeout));
+    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (devaddr >> 1), complete_packet, length + 1, 0, 0, TIME_MS2I(timeout));
     return i2c_epilogue(status);
 }
 
 i2c_status_t i2c_write_register16(uint8_t devaddr, uint16_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout) {
-    i2c_address = devaddr;
     i2cStart(&I2C_DRIVER, &i2cconfig);
 
     uint8_t complete_packet[length + 2];
@@ -195,25 +184,27 @@ i2c_status_t i2c_write_register16(uint8_t devaddr, uint16_t regaddr, const uint8
     complete_packet[0] = regaddr >> 8;
     complete_packet[1] = regaddr & 0xFF;
 
-    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), complete_packet, length + 2, 0, 0, TIME_MS2I(timeout));
+    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (devaddr >> 1), complete_packet, length + 2, 0, 0, TIME_MS2I(timeout));
     return i2c_epilogue(status);
 }
 
 i2c_status_t i2c_read_register(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
-    i2c_address = devaddr;
     i2cStart(&I2C_DRIVER, &i2cconfig);
-    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), &regaddr, 1, data, length, TIME_MS2I(timeout));
+    msg_t status = i2cMasterTransmitTimeout(&I2C_DRIVER, (devaddr >> 1), &regaddr, 1, data, length, TIME_MS2I(timeout));
     return i2c_epilogue(status);
 }
 
 i2c_status_t i2c_read_register16(uint8_t devaddr, uint16_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
-    i2c_address = devaddr;
     i2cStart(&I2C_DRIVER, &i2cconfig);
     uint8_t register_packet[2] = {regaddr >> 8, regaddr & 0xFF};
-    msg_t   status             = i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), register_packet, 2, data, length, TIME_MS2I(timeout));
+    msg_t   status             = i2cMasterTransmitTimeout(&I2C_DRIVER, (devaddr >> 1), register_packet, 2, data, length, TIME_MS2I(timeout));
     return i2c_epilogue(status);
 }
 
-void i2c_stop(void) {
-    i2cStop(&I2C_DRIVER);
-}
+__attribute__((weak)) i2c_status_t i2c_ping_address(uint8_t address, uint16_t timeout) {
+    // ChibiOS does not provide low level enough control to check for an ack.
+    // Best effort instead tries reading register 0 which will either succeed or timeout.
+    // This approach may produce false negative results for I2C devices that do not respond to a register 0 read request.
+    uint8_t data = 0;
+    return i2c_readReg(address, 0, &data, sizeof(data), timeout);
+}
\ No newline at end of file
diff --git a/platforms/chibios/drivers/i2c_master.h b/platforms/chibios/drivers/i2c_master.h
index 5f16367831..132ffd14c0 100644
--- a/platforms/chibios/drivers/i2c_master.h
+++ b/platforms/chibios/drivers/i2c_master.h
@@ -40,11 +40,10 @@ typedef int16_t i2c_status_t;
 #define I2C_STATUS_TIMEOUT (-2)
 
 void         i2c_init(void);
-i2c_status_t i2c_start(uint8_t address);
 i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_write_register(uint8_t devaddr, uint8_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_write_register16(uint8_t devaddr, uint16_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_read_register(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_read_register16(uint8_t devaddr, uint16_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
-void         i2c_stop(void);
+i2c_status_t i2c_ping_address(uint8_t address, uint16_t timeout);