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/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Temperature sensor module for Chrome EC */
#include "board.h"
#include "console.h"
#include "i2c.h"
#include "task.h"
#include "timer.h"
#include "registers.h"
#include "uart.h"
#include "util.h"
#define NUM_PORTS 6
static task_id_t task_waiting_on_port[NUM_PORTS];
static int wait_idle(int port)
{
int i;
int wait_msg;
i = LM4_I2C_MCS(port);
if (i & 0x01) {
/* Port is busy, so wait for the interrupt */
task_waiting_on_port[port] = task_get_current();
LM4_I2C_MIMR(port) = 0x03;
wait_msg = task_wait_msg(1000000);
LM4_I2C_MIMR(port) = 0x00;
task_waiting_on_port[port] = -1;
if (wait_msg == 1 << TASK_ID_TIMER)
return EC_ERROR_TIMEOUT;
i = LM4_I2C_MCS(port);
}
/* Check for errors */
if (i & 0x02)
return EC_ERROR_UNKNOWN;
return EC_SUCCESS;
}
int i2c_read16(int port, int slave_addr, int offset, int* data)
{
int rv;
int d;
*data = 0;
/* Transmit the offset address to the slave; leave the master in
* transmit state. */
LM4_I2C_MSA(port) = (slave_addr & 0xff) | 0x00;
LM4_I2C_MDR(port) = offset & 0xff;
LM4_I2C_MCS(port) = 0x03;
rv = wait_idle(port);
if (rv)
return rv;
/* Send repeated start followed by receive */
LM4_I2C_MSA(port) = (slave_addr & 0xff) | 0x01;
LM4_I2C_MCS(port) = 0x0b;
rv = wait_idle(port);
if (rv)
return rv;
/* Read the first byte */
d = LM4_I2C_MDR(port) & 0xff;
/* Issue another read and then a stop. */
LM4_I2C_MCS(port) = 0x05;
rv = wait_idle(port);
if (rv)
return rv;
/* Read the second byte */
if (slave_addr & I2C_FLAG_BIG_ENDIAN)
*data = (d << 8) | (LM4_I2C_MDR(port) & 0xff);
else
*data = ((LM4_I2C_MDR(port) & 0xff) << 8) | d;
return EC_SUCCESS;
}
int i2c_write16(int port, int slave_addr, int offset, int data)
{
int rv;
/* Transmit the offset address to the slave; leave the master in
* transmit state. */
LM4_I2C_MDR(port) = offset & 0xff;
LM4_I2C_MSA(port) = (slave_addr & 0xff) | 0x00;
LM4_I2C_MCS(port) = 0x03;
rv = wait_idle(port);
if (rv)
return rv;
/* Transmit the first byte */
if (slave_addr & I2C_FLAG_BIG_ENDIAN)
LM4_I2C_MDR(port) = (data >> 8) & 0xff;
else
LM4_I2C_MDR(port) = data & 0xff;
LM4_I2C_MCS(port) = 0x01;
rv = wait_idle(port);
if (rv)
return rv;
/* Transmit the second byte and then a stop */
if (slave_addr & I2C_FLAG_BIG_ENDIAN)
LM4_I2C_MDR(port) = data & 0xff;
else
LM4_I2C_MDR(port) = (data >> 8) & 0xff;
LM4_I2C_MCS(port) = 0x05;
return wait_idle(port);
}
/*****************************************************************************/
/* Interrupt handlers */
/* Handles an interrupt on the specified port. */
static void handle_interrupt(int port)
{
int id = task_waiting_on_port[port];
/* Clear the interrupt status*/
LM4_I2C_MICR(port) = LM4_I2C_MMIS(port);
/* Wake up the task which was waiting on the interrupt, if any */
/* TODO: send message based on I2C port number? */
if (id != TASK_ID_INVALID)
task_send_msg(id, id, 0);
}
static void i2c0_interrupt(void) { handle_interrupt(0); }
static void i2c1_interrupt(void) { handle_interrupt(1); }
static void i2c2_interrupt(void) { handle_interrupt(2); }
static void i2c3_interrupt(void) { handle_interrupt(3); }
static void i2c4_interrupt(void) { handle_interrupt(4); }
static void i2c5_interrupt(void) { handle_interrupt(5); }
DECLARE_IRQ(8, i2c0_interrupt, 2);
DECLARE_IRQ(37, i2c1_interrupt, 2);
DECLARE_IRQ(68, i2c2_interrupt, 2);
DECLARE_IRQ(69, i2c3_interrupt, 2);
DECLARE_IRQ(109, i2c4_interrupt, 2);
DECLARE_IRQ(110, i2c5_interrupt, 2);
/*****************************************************************************/
/* Console commands */
static void scan_bus(int port, char *desc)
{
int rv;
int a;
uart_printf("Scanning %s I2C bus...\n", desc);
for (a = 0; a < 0x100; a += 2) {
uart_puts(".");
/* Do a single read */
LM4_I2C_MSA(port) = a | 0x01;
LM4_I2C_MCS(port) = 0x07;
rv = wait_idle(port);
if (rv == EC_SUCCESS)
uart_printf("\nFound device at 0x%02x\n", a);
}
uart_puts("\n");
}
static int command_scan(int argc, char **argv)
{
scan_bus(I2C_PORT_THERMAL, "thermal");
scan_bus(I2C_PORT_BATTERY, "battery");
scan_bus(I2C_PORT_CHARGER, "charger");
uart_puts("done.\n");
return EC_SUCCESS;
}
static const struct console_command console_commands[] = {
{"i2cscan", command_scan},
};
static const struct console_group command_group = {
"I2C", console_commands, ARRAY_SIZE(console_commands)
};
/*****************************************************************************/
/* Initialization */
/* Configures GPIOs for the module. */
static void configure_gpio(void)
{
volatile uint32_t scratch __attribute__((unused));
/* Enable GPIOG module and delay a few clocks */
LM4_SYSTEM_RCGCGPIO |= 0x0040;
scratch = LM4_SYSTEM_RCGCGPIO;
/* Use alternate function 3 for PG6:7 */
LM4_GPIO_AFSEL(LM4_GPIO_G) |= 0xc0;
LM4_GPIO_PCTL(LM4_GPIO_G) = (LM4_GPIO_PCTL(LM4_GPIO_G) & 0x00ffffff) |
0x33000000;
LM4_GPIO_DEN(LM4_GPIO_G) |= 0xc0;
/* Configure SDA as open-drain. SCL should not be open-drain,
* since it has an internal pull-up. */
LM4_GPIO_ODR(LM4_GPIO_G) |= 0x80;
}
int i2c_init(void)
{
volatile uint32_t scratch __attribute__((unused));
int i;
/* Enable I2C modules and delay a few clocks */
LM4_SYSTEM_RCGCI2C |= (1 << I2C_PORT_THERMAL) |
(1 << I2C_PORT_BATTERY) | (1 << I2C_PORT_CHARGER);
scratch = LM4_SYSTEM_RCGCI2C;
/* Configure GPIOs */
configure_gpio();
/* No tasks are waiting on ports */
for (i = 0; i < NUM_PORTS; i++)
task_waiting_on_port[i] = TASK_ID_INVALID;
/* Initialize ports as master, with interrupts enabled */
LM4_I2C_MCR(I2C_PORT_THERMAL) = 0x10;
LM4_I2C_MTPR(I2C_PORT_THERMAL) =
(CPU_CLOCK / (I2C_SPEED_THERMAL * 10 * 2)) - 1;
LM4_I2C_MCR(I2C_PORT_BATTERY) = 0x10;
LM4_I2C_MTPR(I2C_PORT_BATTERY) =
(CPU_CLOCK / (I2C_SPEED_BATTERY * 10 * 2)) - 1;
LM4_I2C_MCR(I2C_PORT_CHARGER) = 0x10;
LM4_I2C_MTPR(I2C_PORT_CHARGER) =
(CPU_CLOCK / (I2C_SPEED_CHARGER * 10 * 2)) - 1;
console_register_commands(&command_group);
return EC_SUCCESS;
}
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