/* 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
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
/** BusVoodoo I²C mode (code)
 *  @file busvoodoo_i2c.c
 *  @author King Kévin <kingkevin@cuvoodoo.info>
 *  @date 2018
 *  @note peripherals used: I2C @ref busvoodoo_i2c
 */
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // standard utilities
#include <string.h> // string utilities

/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/i2c.h> // I2C library

/* own libraries */
#include "global.h" // board definitions
#include "print.h" // printing utilities
#include "menu.h" // menu definitions
#include "i2c_master.h" // I2C utilities
#include "busvoodoo_global.h" // BusVoodoo definitions
#include "busvoodoo_oled.h" // OLED utilities
#include "busvoodoo_i2c.h" // own definitions

/** @defgroup busvoodoo_i2c I2C peripheral to communicate with I2C devices
 *  @{
 */
#define BUSVOODOO_I2C I2C2 /**< I2C peripheral */
/** @} */

/** mode setup stage */
static enum busvoodoo_i2c_setting_t {
	BUSVOODOO_I2C_SETTING_NONE,
	BUSVOODOO_I2C_SETTING_SPEED,
	BUSVOODOO_I2C_SETTING_ADDRESSBITS,
	BUSVOODOO_I2C_SETTING_PULLUP,
	BUSVOODOO_I2C_SETTING_DONE,
} busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE;
/** I2C speed (in kHz) */
uint16_t busvoodoo_i2c_speed = 100;
/** I2C address bits (7 or 10) */
uint8_t busvoodoo_i2c_addressbits = 7;
/** if embedded or external pull-up resistors are use */
bool busvoodoo_i2c_embedded_pullup = true;

/** setup I2C mode
 *  @param[out] prefix terminal prompt prefix
 *  @param[in] line terminal prompt line to configure mode
 *  @return if setup is complete
 */
static bool busvoodoo_i2c_setup(char** prefix, const char* line)
{
	bool complete = false; // is the setup complete
	if (NULL==line) { // first call
		busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; // re-start configuration
	}
	switch (busvoodoo_i2c_setting) {
		case BUSVOODOO_I2C_SETTING_NONE:
			snprintf(busvoodoo_global_string, LENGTH(busvoodoo_global_string), "speed in kHz (1-400) [%u]", busvoodoo_i2c_speed);
			*prefix = busvoodoo_global_string; // ask for speed
			busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_SPEED;
			break;
		case BUSVOODOO_I2C_SETTING_SPEED:
			if (NULL==line || 0==strlen(line)) { // use default setting
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_ADDRESSBITS; // go to next setting
			} else { // setting provided
				uint32_t speed = atoi(line); // parse setting
				if (speed>0 && speed<=400) { // check setting
					busvoodoo_i2c_speed = speed; // remember setting
					busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_ADDRESSBITS; // go to next setting
				}
			}
			if (BUSVOODOO_I2C_SETTING_ADDRESSBITS==busvoodoo_i2c_setting) { // if next setting
				snprintf(busvoodoo_global_string, LENGTH(busvoodoo_global_string), "address size in bits (7,10) [%u]", busvoodoo_i2c_addressbits); // prepare next setting
				*prefix = busvoodoo_global_string; // display next setting
			}
			break;
		case BUSVOODOO_I2C_SETTING_ADDRESSBITS:
			if (NULL==line || 0==strlen(line)) { // use default setting
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_PULLUP; // go to next setting
			} else { // setting provided
				uint8_t addressbits = atoi(line); // parse setting
				if (7==addressbits || 10==addressbits) { // check setting
					busvoodoo_i2c_addressbits = addressbits; // remember setting
					busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_PULLUP; // go to next setting
				}
			}
			if (BUSVOODOO_I2C_SETTING_PULLUP==busvoodoo_i2c_setting) { // if next setting
				printf("1) open-drain, with embedded pull-up resistors (2kO)\n");
				printf("2) open-drain, with external pull-up resistors\n");
				snprintf(busvoodoo_global_string, LENGTH(busvoodoo_global_string), "drive mode (1,2) [%c]", busvoodoo_i2c_embedded_pullup ? '1' : '2'); // show drive mode
				*prefix = busvoodoo_global_string; // display next setting
			}
			break;
		case BUSVOODOO_I2C_SETTING_PULLUP:
			if (NULL==line || 0==strlen(line)) { // use default setting
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_DONE; // go to next setting
			} else if (1==strlen(line)) { // setting provided
				uint8_t drive = atoi(line); // parse setting
				if (1==drive || 2==drive) { // check setting
					busvoodoo_i2c_embedded_pullup = (1==drive); // remember setting
					busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_DONE; // go to next setting
				}
			}
			if (BUSVOODOO_I2C_SETTING_DONE==busvoodoo_i2c_setting) { // we have all settings, configure I2C
				i2c_master_setup(BUSVOODOO_I2C, false); // setup I2C
				if (busvoodoo_i2c_embedded_pullup) {
					busvoodoo_embedded_pullup(true); // set pull-up
					printf("use LV to set voltage\n");
				}
				led_off(); // disable LED because there is no activity
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; // restart settings next time
				*prefix = "I2C"; // display mode
				busvoodoo_oled_text_left(*prefix); // set mode title on OLED display
				const char* pinout_io[10] = {"GND", "5V", "3V3", "LV", "SDA", "SCL", NULL, NULL}; // HiZ mode pinout
				for (uint8_t i=0; i<LENGTH(pinout_io) && i<LENGTH(busvoodoo_global_pinout_io); i++) {
					busvoodoo_global_pinout_io[i] = pinout_io[i]; // set pin names
				}
				busvoodoo_oled_text_pinout(pinout_io, true); // set pinout on display
				busvoodoo_oled_update(); // update display to show text and pinout
				complete = true; // configuration is complete
			}
			break;
		case BUSVOODOO_I2C_SETTING_DONE: // this case is already handled before
		default: // unknown case
			busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; // restart settings next time
			complete = false; // restart setting
			break;
	}
	return complete;
}

/** exit I2C mode
 */
static void busvoodoo_i2c_exit(void)
{
	i2c_master_release(BUSVOODOO_I2C); // release I2C peripheral
	busvoodoo_embedded_pullup(false); // disable embedded pull-ups
}

// command handlers

/** command to scan for slave devices
 *  @param[in] argument no argument required
 */
static void busvoodoo_i2c_command_scan(void* argument)
{
	(void)argument; // we won't use the argument
	if (!i2c_master_check_signals(BUSVOODOO_I2C)) { // ensure SCL and SDA are high
		printf("SCL or SDA is/are low. The signals need to be pulled up\n");
		if (busvoodoo_i2c_embedded_pullup) {
			printf("set pull-up voltage with LV\n");
		}
		led_blink(0.5, 0.5); // show error on LEDs
		return; // stop here
	} else {
		led_off(); // switch LEDs off
	}
	printf("scanning for I2C slaves\n");
	uint16_t i2c_slaves = 0; // number of slaves found
	// check for I2C slaves by going through the address space
	for (uint16_t address=0; address < (1<<busvoodoo_i2c_addressbits); address++) {
		if (!i2c_master_start(BUSVOODOO_I2C)) { // send start condition
			i2c_master_stop(BUSVOODOO_I2C); // send stop condition
			printf("start condition failed\n"); // show error to user
			led_blink(0.5, 0.5); // show error on LEDs
			break; // stop scanning
		} else {
			busvoodoo_led_blue(100); // pulse blue LED to show transmission
		}
		if (i2c_master_select_slave(BUSVOODOO_I2C, address, false)) { // try to select slave
			busvoodoo_led_red(100); // pulse red LED to show we found a slave
			printf((busvoodoo_i2c_addressbits>7) ? "0x%03x " : "0x%02x ", address); // display address
			i2c_slaves++; // increase slave count
		}
		i2c_master_stop(BUSVOODOO_I2C); // send stop condition
	}
	if (i2c_slaves>0) {
		printf("\n");
	}
	printf("%u slave(s) found\n", i2c_slaves); // show summary
}

static const struct menu_command_t busvoodoo_i2c_commands[] = {
	{
		's',
		"scan",
		"scan for slave devices",
		MENU_ARGUMENT_NONE,
		NULL,
		&busvoodoo_i2c_command_scan,
	},
};

struct busvoodoo_mode_t busvoodoo_i2c_mode = {
	"i2c",
	"Inter-Integrated Circuit",
	&busvoodoo_i2c_setup,
	busvoodoo_i2c_commands,
	LENGTH(busvoodoo_i2c_commands),
	&busvoodoo_i2c_exit,
};