Add generic i2c interface

Signed-off-by: Florian Heilmann <Florian.Heilmann@gmx.net>

src/Kconfig

@@ -47,6 +47,9 @@ config HAVE_GPIO_ADC
 config HAVE_GPIO_SPI
     bool
     default n
+config HAVE_GPIO_I2C
+    bool
+    default n
 config HAVE_GPIO_HARD_PWM
     bool
     default n

src/Makefile

@@ -4,6 +4,7 @@ src-y += sched.c command.c basecmd.c debugcmds.c
 src-$(CONFIG_HAVE_GPIO) += gpiocmds.c stepper.c endstop.c
 src-$(CONFIG_HAVE_GPIO_ADC) += adccmds.c
 src-$(CONFIG_HAVE_GPIO_SPI) += spicmds.c thermocouple.c
+src-$(CONFIG_HAVE_GPIO_I2C) += i2ccmds.c
 src-$(CONFIG_HAVE_GPIO_HARD_PWM) += pwmcmds.c
 src-$(CONFIG_HAVE_GPIO_BITBANGING) += lcd_st7920.c lcd_hd44780.c buttons.c \
     tmcuart.c

src/i2ccmds.c

@@ -0,0 +1,76 @@
+// Commands for sending messages on an I2C bus
+//
+// Copyright (C) 2018  Florian Heilmann <Florian.Heilmann@gmx.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "basecmd.h" //oid_alloc
+#include "command.h"  //sendf
+#include "sched.h" //DECL_COMMAND
+#include "board/gpio.h" //i2c_write/read/setup
+
+struct i2cdev_s {
+    struct i2c_config i2c_config;
+};
+
+void
+command_config_i2c(uint32_t *args)
+{
+    struct i2cdev_s *i2c = oid_alloc(args[0], command_config_i2c
+                                     , sizeof(*i2c));
+    i2c->i2c_config = i2c_setup(args[1], args[2], args[3]);
+}
+DECL_COMMAND(command_config_i2c,
+             "config_i2c oid=%c bus=%u rate=%u addr=%u");
+void
+command_i2c_write(uint32_t *args)
+{
+    uint8_t oid = args[0];
+    struct i2cdev_s *i2c = oid_lookup(oid, command_config_i2c);
+    uint8_t data_len = args[1];
+    uint8_t *data = (void*)(size_t)args[2];
+    i2c_write(i2c->i2c_config, data_len, data);
+}
+DECL_COMMAND(command_i2c_write, "i2c_write oid=%c data=%*s");
+
+void
+command_i2c_read(uint32_t * args)
+{
+    uint8_t oid = args[0];
+    struct i2cdev_s *i2c = oid_lookup(oid, command_config_i2c);
+    uint8_t reg_len = args[1];
+    uint8_t *reg = (void*)(size_t)args[2];
+    uint32_t data_len = args[3];
+    uint8_t receive_array[data_len];
+    uint8_t *data = (void*)(size_t)receive_array;
+    i2c_read(i2c->i2c_config, reg_len, reg, data_len, data);
+    sendf("i2c_read_response oid=%c response=%*s", oid, data_len, data);
+}
+DECL_COMMAND(command_i2c_read, "i2c_read oid=%c reg=%*s read_len=%u");
+
+void
+command_i2c_modify_bits(uint32_t *args)
+{
+    uint8_t oid = args[0];
+    struct i2cdev_s *i2c = oid_lookup(oid, command_config_i2c);
+    uint8_t reg_len = args[1];
+    uint8_t *reg = (void*)(size_t)args[2];
+    uint32_t clear_set_len = args[3];
+    if (clear_set_len % 2 != 0) {
+        shutdown("i2c_modify_bits: Odd number of bits!");
+    }
+    uint8_t data_len = clear_set_len/2;
+    uint8_t *clear_set = (void*)(size_t)args[4];
+    uint8_t receive_array[reg_len + data_len];
+    uint8_t *receive_data = (void*)(size_t)receive_array;
+    for (int i = 0; i < reg_len; i++) {
+        *(receive_data + i) = *(reg + i);
+    }
+    i2c_read(i2c->i2c_config, reg_len, reg, data_len, receive_data + reg_len);
+    for (int i = 0; i < data_len; i++) {
+        *(receive_data + reg_len + i) &= ~(*(clear_set + i));
+        *(receive_data + reg_len + i) |= *(clear_set + clear_set_len/2 + i);
+    }
+    i2c_write(i2c->i2c_config, reg_len + data_len, receive_array);
+}
+DECL_COMMAND(command_i2c_modify_bits, "i2c_modify_bits oid=%c reg=%*s clear_set_bits=%*s");