/**
* @file
*
* @ingroup arm_beagle
*
* @brief BeagleBoard I2C bus initialization and API Support.
*/
/*
* Copyright (c) 2016 Punit Vara <punitvara@gmail.com>
* Copyright (c) 2017 Sichen Zhao <zsc19940506@gmail.com>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
/*
* Modified on Punit Vara<punitvara@gmail.com> works, currently
* the i2c file is working on the Beaglebone Black board(AM335x)
*/
#include <stdio.h>
#include <bsp/i2c.h>
#include <libcpu/am335x.h>
#include <rtems/irq-extension.h>
#include <rtems/counter.h>
#include <bsp/bbb-gpio.h>
#include <rtems/score/assert.h>
static void am335x_i2c0_pinmux( bbb_i2c_bus *bus )
{
REG( bus->regs + AM335X_CONF_I2C0_SDA ) =
( BBB_RXACTIVE | BBB_SLEWCTRL | BBB_PU_EN );
REG( bus->regs + AM335X_CONF_I2C0_SCL ) =
( BBB_RXACTIVE | BBB_SLEWCTRL | BBB_PU_EN );
}
static void I2C0ModuleClkConfig( void )
{
/* Writing to MODULEMODE field of AM335X_CM_WKUP_I2C0_CLKCTRL register. */
REG( AM335X_SOC_CM_WKUP_REGS + AM335X_CM_WKUP_I2C0_CLKCTRL ) |=
AM335X_CM_WKUP_I2C0_CLKCTRL_MODULEMODE_ENABLE;
/* Waiting for MODULEMODE field to reflect the written value. */
while ( AM335X_CM_WKUP_I2C0_CLKCTRL_MODULEMODE_ENABLE !=
( REG( AM335X_SOC_CM_WKUP_REGS + AM335X_CM_WKUP_I2C0_CLKCTRL ) &
AM335X_CM_WKUP_I2C0_CLKCTRL_MODULEMODE ) ) ;
/*
* Waiting for IDLEST field in AM335X_CM_WKUP_CONTROL_CLKCTRL
* register to attain desired value.
*/
while ( ( AM335X_CM_WKUP_CONTROL_CLKCTRL_IDLEST_FUNC <<
AM335X_CM_WKUP_CONTROL_CLKCTRL_IDLEST_SHIFT ) !=
( REG( AM335X_SOC_CM_WKUP_REGS + AM335X_CM_WKUP_CONTROL_CLKCTRL ) &
AM335X_CM_WKUP_CONTROL_CLKCTRL_IDLEST ) ) ;
/*
* Waiting for CLKACTIVITY_I2C0_GFCLK field in AM335X_CM_WKUP_CLKSTCTRL
* register to attain desired value.
*/
while ( AM335X_CM_WKUP_CLKSTCTRL_CLKACTIVITY_I2C0_GFCLK !=
( REG( AM335X_SOC_CM_WKUP_REGS + AM335X_CM_WKUP_CLKSTCTRL ) &
AM335X_CM_WKUP_CLKSTCTRL_CLKACTIVITY_I2C0_GFCLK ) ) ;
/*
* Waiting for IDLEST field in AM335X_CM_WKUP_I2C0_CLKCTRL register to attain
* desired value.
*/
while ( ( AM335X_CM_WKUP_I2C0_CLKCTRL_IDLEST_FUNC <<
AM335X_CM_WKUP_I2C0_CLKCTRL_IDLEST_SHIFT ) !=
( REG( AM335X_SOC_CM_WKUP_REGS + AM335X_CM_WKUP_I2C0_CLKCTRL ) &
AM335X_CM_WKUP_I2C0_CLKCTRL_IDLEST ) ) ;
}
static void am335x_i2c_reset( bbb_i2c_bus *bus )
{
volatile bbb_i2c_regs *regs = bus->regs;
int timeout = I2C_TIMEOUT;
if ( REG( ®s->BBB_I2C_CON ) & BBB_I2C_CON_EN ) {
REG( ®s->BBB_I2C_CON ) = BBB_I2C_CON_CLR;
udelay( 50000 );
}
REG( ®s->BBB_I2C_SYSC ) = BBB_I2C_SYSC_SRST; /* for ES2 after soft reset */
udelay( 1000 );
REG( ®s->BBB_I2C_CON ) = BBB_I2C_CON_EN;
while ( !( REG( ®s->BBB_I2C_SYSS ) & BBB_I2C_SYSS_RDONE ) && timeout-- ) {
if ( timeout <= 0 ) {
puts( "ERROR: Timeout in soft-reset\n" );
return;
}
udelay( 1000 );
}
}
/*
* Possible values for msg->flag
* - @ref I2C_M_TEN,
* - @ref I2C_M_RD,
* - @ref I2C_M_STOP,
* - @ref I2C_M_NOSTART,
* - @ref I2C_M_REV_DIR_ADDR,
* - @ref I2C_M_IGNORE_NAK,
* - @ref I2C_M_NO_RD_ACK, and
* - @ref I2C_M_RECV_LEN.
*/
static void am335x_i2c_set_address_size(
const i2c_msg *msgs,
volatile bbb_i2c_regs *regs
)
{
/*
* Can be configured multiple modes here.
* Need to think about own address modes
*/
if ( ( msgs->flags & I2C_M_TEN ) == 0 ) {
/* 7-bit mode slave address mode */
REG( ®s->BBB_I2C_CON ) = AM335X_I2C_CFG_7BIT_SLAVE_ADDR;
} else {
/* 10-bit slave address mode */
REG( ®s->BBB_I2C_CON ) = AM335X_I2C_CFG_10BIT_SLAVE_ADDR;
}
}
static void am335x_i2c_next_byte( bbb_i2c_bus *bus )
{
i2c_msg *msg;
++bus->msgs;
--bus->msg_todo;
msg = &bus->msgs[ 0 ];
bus->current_msg_todo = msg->len;
bus->current_msg_byte = msg->buf;
}
static void am335x_i2c_masterint_enable(
volatile bbb_i2c_regs *regs,
unsigned int flag
)
{
REG( ®s->BBB_I2C_IRQENABLE_SET ) |= flag;
}
static void am335x_i2c_masterint_disable(
volatile bbb_i2c_regs *regs,
unsigned int flag
)
{
REG( ®s->BBB_I2C_IRQENABLE_CLR ) = flag;
}
static void am335x_int_clear(
volatile bbb_i2c_regs *regs,
unsigned int flag
)
{
REG( ®s->BBB_I2C_IRQSTATUS ) = flag;
}
static void am335x_clean_interrupts( volatile bbb_i2c_regs *regs )
{
am335x_i2c_masterint_enable( regs, BBB_I2C_ALL_FLAGS );
am335x_int_clear( regs, BBB_I2C_ALL_FLAGS );
am335x_i2c_masterint_disable( regs, BBB_I2C_ALL_FLAGS );
}
static void am335x_i2c_setup_read_transfer(
bbb_i2c_bus *bus,
volatile bbb_i2c_regs *regs,
const i2c_msg *msgs,
bool send_stop
)
{
REG( ®s->BBB_I2C_CNT ) = bus->current_msg_todo;
REG( ®s->BBB_I2C_CON ) = AM335X_I2C_CFG_MST_RX | AM335X_I2C_CON_I2C_EN;
if ( send_stop ) {
REG( ®s->BBB_I2C_CON ) |= AM335X_I2C_CON_START | AM335X_I2C_CON_STOP;
} else {
REG( ®s->BBB_I2C_CON ) |= AM335X_I2C_CON_START;
}
am335x_i2c_masterint_enable( regs, AM335X_I2C_INT_RECV_READY |
AM335X_I2C_IRQSTATUS_ARDY );
}
static void am335x_i2c_continue_read_transfer(
bbb_i2c_bus *bus,
volatile bbb_i2c_regs *regs
)
{
bus->current_msg_byte[ bus->already_transferred ] =
REG( ®s->BBB_I2C_DATA );
bus->already_transferred++;
REG( ®s->BBB_I2C_IRQSTATUS ) = AM335X_I2C_INT_RECV_READY;
if ( bus->already_transferred == bus->current_msg_todo - 1 ) {
REG( ®s->BBB_I2C_CON ) |= AM335X_I2C_CON_STOP;
}
}
static void am335x_i2c_continue_write(
bbb_i2c_bus *bus,
volatile bbb_i2c_regs *regs
)
{
if ( bus->already_transferred == bus->msg_todo ) {
REG( ®s->BBB_I2C_DATA ) =
bus->current_msg_byte[ bus->already_transferred ];
REG( ®s->BBB_I2C_IRQSTATUS ) = AM335X_I2C_IRQSTATUS_XRDY;
am335x_i2c_masterint_disable( regs, AM335X_I2C_IRQSTATUS_XRDY );
REG( ®s->BBB_I2C_CON ) |= AM335X_I2C_CON_STOP;
} else {
writeb( bus->current_msg_byte[ bus->already_transferred ],
®s->BBB_I2C_DATA );
REG( ®s->BBB_I2C_IRQSTATUS ) = AM335X_I2C_IRQSTATUS_XRDY;
bus->already_transferred++;
}
}
static void am335x_i2c_setup_write_transfer(
bbb_i2c_bus *bus,
volatile bbb_i2c_regs *regs,
const i2c_msg *msgs
)
{
volatile unsigned int no_bytes;
REG( ®s->BBB_I2C_CNT ) = bus->current_msg_todo;
no_bytes = REG( ®s->BBB_I2C_CNT );
(void) no_bytes; /* indicate we know that no_bytes is not referenced again */
REG( ®s->BBB_I2C_SA ) = msgs->addr;
REG( ®s->BBB_I2C_CON ) = AM335X_I2C_CFG_MST_TX | AM335X_I2C_CON_I2C_EN;
am335x_clean_interrupts( regs );
am335x_i2c_masterint_enable( regs, AM335X_I2C_IRQSTATUS_XRDY );
REG( ®s->BBB_I2C_CON ) |= AM335X_I2C_CON_START | AM335X_I2C_CON_STOP;
}
static void am335x_i2c_setup_transfer(
bbb_i2c_bus *bus,
volatile bbb_i2c_regs *regs
)
{
const i2c_msg *msgs = bus->msgs;
uint32_t msg_todo = bus->msg_todo;
bool send_stop = false;
uint32_t i;
bus->current_todo = msgs[ 0 ].len;
for ( i = 1; i < msg_todo && ( msgs[ i ].flags & I2C_M_NOSTART ) != 0;
++i ) {
bus->current_todo += msgs[ i ].len;
}
regs = bus->regs;
REG( &bus->regs->BBB_I2C_BUF ) |= AM335X_I2C_BUF_TXFIFO_CLR;
REG( &bus->regs->BBB_I2C_BUF ) |= AM335X_I2C_BUF_RXFIFO_CLR;
am335x_i2c_set_address_size( msgs, regs );
bus->read = ( msgs->flags & I2C_M_RD ) != 0;
bus->already_transferred = ( bus->read == true ) ? 0 : 1;
if ( bus->read ) {
if ( bus->current_msg_todo == 1 ) {
send_stop = true;
}
am335x_i2c_setup_read_transfer( bus, regs, msgs, send_stop );
} else {
am335x_i2c_setup_write_transfer( bus, regs, msgs );
}
}
static void am335x_i2c_interrupt( void *arg )
{
bbb_i2c_bus *bus = arg;
volatile bbb_i2c_regs *regs = bus->regs;
/* Get status of enabled interrupts */
uint32_t irqstatus = REG( ®s->BBB_I2C_IRQSTATUS );
bool done = false;
/*
* Clear all enabled interrupt except receive ready
* and transmit ready interrupt in status register
*/
REG( ®s->BBB_I2C_IRQSTATUS ) =
( irqstatus & ~( AM335X_I2C_IRQSTATUS_RRDY |
AM335X_I2C_IRQSTATUS_XRDY ) );
if ( irqstatus & AM335X_I2C_INT_RECV_READY ) {
am335x_i2c_continue_read_transfer( bus, regs );
}
if ( irqstatus & AM335X_I2C_IRQSTATUS_XRDY ) {
am335x_i2c_continue_write( bus, regs );
}
if ( irqstatus & AM335X_I2C_IRQSTATUS_NACK ) {
done = true;
am335x_i2c_masterint_disable( regs, AM335X_I2C_IRQSTATUS_NACK );
}
if ( irqstatus & AM335X_I2C_IRQSTATUS_ARDY ) {
done = true;
REG( ®s->BBB_I2C_IRQSTATUS ) = BBB_I2C_STAT_ARDY;
}
if ( irqstatus & AM335X_I2C_IRQSTATUS_BF ) {
REG( ®s->BBB_I2C_IRQSTATUS ) = AM335X_I2C_IRQSTATUS_BF;
}
if ( done ) {
uint32_t err = irqstatus & BBB_I2C_IRQ_ERROR;
am335x_i2c_next_byte( bus );
if ( bus->msg_todo == 0 ) {
rtems_status_code sc;
am335x_i2c_masterint_disable( regs, ( AM335X_I2C_IRQSTATUS_RRDY |
AM335X_I2C_IRQSTATUS_XRDY |
AM335X_I2C_IRQSTATUS_BF ) );
REG( ®s->BBB_I2C_IRQSTATUS ) = err;
sc = rtems_event_transient_send( bus->task_id );
_Assert( sc == RTEMS_SUCCESSFUL );
(void) sc;
} else {
am335x_i2c_setup_transfer( bus, regs );
}
}
}
static int am335x_i2c_transfer(
i2c_bus *base,
i2c_msg *msgs,
uint32_t msg_count
)
{
rtems_status_code sc;
bbb_i2c_bus *bus = (bbb_i2c_bus *) base;
volatile bbb_i2c_regs *regs;
uint32_t i;
rtems_task_wake_after( 1 );
if ( msg_count < 1 ) {
return 1;
}
for ( i = 0; i < msg_count; ++i ) {
if ( ( msgs[ i ].flags & I2C_M_RECV_LEN ) != 0 ) {
return -EINVAL;
}
}
bus->msgs = &msgs[ 0 ];
bus->msg_todo = msg_count;
bus->current_msg_todo = msgs[ 0 ].len;
bus->current_msg_byte = msgs[ 0 ].buf;
bus->task_id = rtems_task_self();
regs = bus->regs;
am335x_i2c_setup_transfer( bus, regs );
REG( ®s->BBB_I2C_IRQENABLE_SET ) = BBB_I2C_IRQ_USED;
sc = rtems_event_transient_receive( RTEMS_WAIT, bus->base.timeout );
if ( sc != RTEMS_SUCCESSFUL ) {
am335x_i2c_reset( bus );
rtems_event_transient_clear();
return -ETIMEDOUT;
}
return 0;
}
static int am335x_i2c_set_clock(
i2c_bus *base,
unsigned long clock
)
{
bbb_i2c_bus *bus = (bbb_i2c_bus *) base;
uint32_t prescaler, divider;
prescaler = ( BBB_I2C_SYSCLK / BBB_I2C_INTERNAL_CLK ) - 1;
REG( &bus->regs->BBB_I2C_PSC ) = prescaler;
divider = BBB_I2C_INTERNAL_CLK / ( 2 * clock );
REG( &bus->regs->BBB_I2C_SCLL ) = ( divider - 7 );
REG( &bus->regs->BBB_I2C_SCLH ) = ( divider - 5 );
return 0;
}
static void am335x_i2c_destroy( i2c_bus *base )
{
bbb_i2c_bus *bus = (bbb_i2c_bus *) base;
rtems_status_code sc;
sc = rtems_interrupt_handler_remove( bus->irq, am335x_i2c_interrupt, bus );
_Assert( sc == RTEMS_SUCCESSFUL );
(void) sc;
i2c_bus_destroy_and_free( &bus->base );
}
int am335x_i2c_bus_register(
const char *bus_path,
uintptr_t register_base,
uint32_t input_clock,
rtems_vector_number irq
)
{
bbb_i2c_bus *bus;
rtems_status_code sc;
int err;
/* Check bus number is >0 & <MAX */
bus = (bbb_i2c_bus *) i2c_bus_alloc_and_init( sizeof( *bus ) );
if ( bus == NULL ) {
return -1;
}
bus->regs = (volatile bbb_i2c_regs *) register_base;
I2C0ModuleClkConfig();
am335x_i2c0_pinmux( bus );
am335x_i2c_reset( bus );
bus->input_clock = input_clock;
err = am335x_i2c_set_clock( &bus->base, I2C_BUS_CLOCK_DEFAULT );
if ( err != 0 ) {
( *bus->base.destroy )( &bus->base );
rtems_set_errno_and_return_minus_one( -err );
}
bus->irq = irq;
REG( &bus->regs->BBB_I2C_IRQSTATUS ) = BBB_I2C_ALL_IRQ_FLAGS;
sc = rtems_interrupt_handler_install(
irq,
"BBB_I2C",
RTEMS_INTERRUPT_UNIQUE,
(rtems_interrupt_handler) am335x_i2c_interrupt,
bus
);
if ( sc != RTEMS_SUCCESSFUL ) {
( *bus->base.destroy )( &bus->base );
rtems_set_errno_and_return_minus_one( EIO );
}
bus->base.transfer = am335x_i2c_transfer;
bus->base.set_clock = am335x_i2c_set_clock;
bus->base.destroy = am335x_i2c_destroy;
return i2c_bus_register( &bus->base, bus_path );
}