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apache / nuttx / ca5a9c711a7b9b70d84385a8523c54cf58a24e9e / . / arch / arm / src / am335x / am335x_i2c.c
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/****************************************************************************
* arch/arm/src/am335x/am335x_i2c.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/clock.h>
#include <nuttx/mutex.h>
#include <nuttx/semaphore.h>
#include <nuttx/i2c/i2c_master.h>
#include <arch/board/board.h>
#include "arm_internal.h"
#include "hardware/am335x_pinmux.h"
#include "hardware/am335x_prcm.h"
#include "hardware/am335x_i2c.h"
#include "am335x_i2c.h"
#include "am335x_gpio.h"
#include "am335x_pinmux.h"
/* At least one I2C peripheral must be enabled */
#if defined(CONFIG_AM335X_I2C0) || defined(CONFIG_AM335X_I2C1) || \
defined(CONFIG_AM335X_I2C2)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define AM335X_I2C_SCLK (48000000)
/* Configuration ************************************************************/
/* CONFIG_I2C_POLLED may be set so that I2C interrupts will not be used.
* Instead, CPU-intensive polling will be used.
*/
/* Interrupt wait timeout in seconds and milliseconds */
#if !defined(CONFIG_AM335X_I2CTIMEOSEC) && !defined(CONFIG_AM335X_I2CTIMEOMS)
# define CONFIG_AM335X_I2CTIMEOSEC 0
# define CONFIG_AM335X_I2CTIMEOMS 500 /* Default is 500 milliseconds */
#elif !defined(CONFIG_AM335X_I2CTIMEOSEC)
# define CONFIG_AM335X_I2CTIMEOSEC 0 /* User provided milliseconds */
#elif !defined(CONFIG_AM335X_I2CTIMEOMS)
# define CONFIG_AM335X_I2CTIMEOMS 0 /* User provided seconds */
#endif
/* Interrupt wait time timeout in system timer ticks */
#ifndef CONFIG_AM335X_I2CTIMEOTICKS
# define CONFIG_AM335X_I2CTIMEOTICKS \
(SEC2TICK(CONFIG_AM335X_I2CTIMEOSEC) + MSEC2TICK(CONFIG_AM335X_I2CTIMEOMS))
#endif
#ifndef CONFIG_AM335X_I2C_DYNTIMEO_STARTSTOP
# define CONFIG_AM335X_I2C_DYNTIMEO_STARTSTOP TICK2USEC(CONFIG_AM335X_I2CTIMEOTICKS)
#endif
/* Debug ********************************************************************/
/* I2C event trace logic. NOTE: trace uses the internal, non-standard,
* low-leveldebug interface syslog() but does not require that any other
* debug is enabled.
*/
#ifndef CONFIG_I2C_TRACE
# define am335x_i2c_tracereset(p)
# define am335x_i2c_tracenew(p,s)
# define am335x_i2c_traceevent(p,e,a)
# define am335x_i2c_tracedump(p)
#endif
#ifndef CONFIG_I2C_NTRACE
# define CONFIG_I2C_NTRACE 32
#endif
#ifdef CONFIG_I2C_SLAVE
# error I2C slave logic is not supported yet for AM335X
#endif
#define I2C_MASTER 1
#define I2C_SLAVE 2
#define MKI2C_OUTPUT(p) (am335x_periph_gpio(p) | PINMUX_SLEW_SLOW | \
PINMUX_PULL_UP_DISABLE | PINMUX_RX_ENABLE | \
GPIO_OUTPUT | GPIO_OUTPUT_ONE)
/****************************************************************************
* Private Types
****************************************************************************/
/* Interrupt state */
enum am335x_intstate_e
{
INTSTATE_IDLE = 0, /* No I2C activity */
INTSTATE_WAITING, /* Waiting for completion of interrupt activity */
INTSTATE_DONE, /* Interrupt activity complete */
};
/* Trace events */
enum am335x_trace_e
{
I2CEVENT_NONE = 0, /* No events have occurred with this status */
I2CEVENT_SENDADDR, /* Start/Master bit set and address sent, param = msgc */
I2CEVENT_SENDBYTE, /* Send byte, param = dcnt */
I2CEVENT_RCVBYTE, /* Read more dta, param = dcnt */
I2CEVENT_NOSTART, /* BTF on last byte with no restart, param = msgc */
I2CEVENT_STARTRESTART, /* Last byte sent, re-starting, param = msgc */
I2CEVENT_STOP, /* Last byte sten, send stop, param = 0 */
I2CEVENT_ERROR /* Error occurred, param = 0 */
};
/* Trace data */
struct am335x_trace_s
{
uint32_t status; /* I2C 32-bit SR2|SR1 status */
uint32_t count; /* Interrupt count when status change */
enum am335x_intstate_e event; /* Last event that occurred with this status */
uint32_t parm; /* Parameter associated with the event */
clock_t time; /* First of event or first status */
};
/* I2C Device hardware configuration */
struct am335x_i2c_config_s
{
uint32_t base; /* I2C base address */
gpio_pinset_t scl_pin; /* GPIO configuration for SCL as SCL */
gpio_pinset_t sda_pin; /* GPIO configuration for SDA as SDA */
uint8_t mode; /* Master or Slave mode */
#ifndef CONFIG_I2C_POLLED
uint32_t irq; /* Event IRQ */
#endif
};
/* I2C Device Private Data */
struct am335x_i2c_priv_s
{
/* Standard I2C operations */
const struct i2c_ops_s *ops;
/* Port configuration */
const struct am335x_i2c_config_s *config;
int refs; /* Reference count */
mutex_t lock; /* Mutual exclusion mutex */
#ifndef CONFIG_I2C_POLLED
sem_t sem_isr; /* Interrupt wait semaphore */
#endif
volatile uint8_t intstate; /* Interrupt handshake (see enum am335x_intstate_e) */
uint8_t msgc; /* Message count */
struct i2c_msg_s *msgv; /* Message list */
uint8_t *ptr; /* Current message buffer */
uint32_t frequency; /* Current I2C frequency */
int dcnt; /* Current message length */
uint16_t flags; /* Current message flags */
/* I2C trace support */
#ifdef CONFIG_I2C_TRACE
int tndx; /* Trace array index */
clock_t start_time; /* Time when the trace was started */
/* The actual trace data */
struct am335x_trace_s trace[CONFIG_I2C_NTRACE];
#endif
uint32_t status; /* End of transfer SR2|SR1 status */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static inline uint32_t am335x_i2c_getreg(struct am335x_i2c_priv_s *priv,
uint16_t offset);
static inline void am335x_i2c_putreg(struct am335x_i2c_priv_s *priv,
uint16_t offset, uint32_t value);
static inline void am335x_i2c_modifyreg(struct am335x_i2c_priv_s *priv,
uint16_t offset, uint32_t clearbits,
uint32_t setbits);
#ifdef CONFIG_AM335X_I2C_DYNTIMEO
static uint32_t am335x_i2c_toticks(int msgc, struct i2c_msg_s *msgs);
#endif /* CONFIG_AM335X_I2C_DYNTIMEO */
static inline int
am335x_i2c_sem_waitdone(struct am335x_i2c_priv_s *priv);
static inline bool
am335x_i2c_sem_waitstop(struct am335x_i2c_priv_s *priv);
#ifdef CONFIG_I2C_TRACE
static void am335x_i2c_tracereset(struct am335x_i2c_priv_s *priv);
static void am335x_i2c_tracenew(struct am335x_i2c_priv_s *priv,
uint32_t status);
static void am335x_i2c_traceevent(struct am335x_i2c_priv_s *priv,
enum am335x_trace_e event, uint32_t parm);
static void am335x_i2c_tracedump(struct am335x_i2c_priv_s *priv);
#endif /* CONFIG_I2C_TRACE */
static void am335x_i2c_setclock(struct am335x_i2c_priv_s *priv,
uint32_t frequency);
static inline void am335x_i2c_sendstart(struct am335x_i2c_priv_s *priv,
uint16_t address);
static inline void am335x_i2c_sendstop(struct am335x_i2c_priv_s *priv);
static inline uint32_t
am335x_i2c_getstatus(struct am335x_i2c_priv_s *priv);
static int am335x_i2c_isr_process(struct am335x_i2c_priv_s *priv);
#ifndef CONFIG_I2C_POLLED
static int am335x_i2c_isr(int irq, void *context, void *arg);
#endif /* !CONFIG_I2C_POLLED */
static int am335x_i2c_init(struct am335x_i2c_priv_s *priv);
static int am335x_i2c_deinit(struct am335x_i2c_priv_s *priv);
static int am335x_i2c_transfer(struct i2c_master_s *dev,
struct i2c_msg_s *msgs, int count);
#ifdef CONFIG_I2C_RESET
static int am335x_i2c_reset(struct i2c_master_s *dev);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/* Trace events strings */
#ifdef CONFIG_I2C_TRACE
static const char *g_trace_names[] =
{
"NONE ",
"SENDADDR ",
"SENDBYTE ",
"RCVBYTE ",
"NOSTART ",
"START/RESTART ",
"STOP ",
"ERROR "
};
#endif
/* I2C interface */
static const struct i2c_ops_s am335x_i2c_ops =
{
.transfer = am335x_i2c_transfer
#ifdef CONFIG_I2C_RESET
, .reset = am335x_i2c_reset
#endif
};
/* I2C device structures */
#ifdef CONFIG_AM335X_I2C0
static const struct am335x_i2c_config_s am335x_i2c0_config =
{
.base = AM335X_I2C0_VADDR,
.scl_pin = GPIO_I2C0_SCL,
.sda_pin = GPIO_I2C0_SDA,
#ifndef CONFIG_I2C_SLAVE
.mode = I2C_MASTER,
#else
.mode = I2C_SLAVE,
#endif
#ifndef CONFIG_I2C_POLLED
.irq = AM335X_IRQ_I2C0,
#endif
};
static struct am335x_i2c_priv_s am335x_i2c0_priv =
{
.ops = &am335x_i2c_ops,
.config = &am335x_i2c0_config,
.refs = 0,
.lock = NXMUTEX_INITIALIZER,
#ifndef CONFIG_I2C_POLLED
.sem_isr = SEM_INITIALIZER(0),
#endif
.intstate = INTSTATE_IDLE,
.msgc = 0,
.msgv = NULL,
.ptr = NULL,
.dcnt = 0,
.flags = 0,
.status = 0
};
#endif
#ifdef CONFIG_AM335X_I2C1
static const struct am335x_i2c_config_s am335x_i2c1_config =
{
.base = AM335X_I2C1_VADDR,
.scl_pin = GPIO_I2C1_SCL,
.sda_pin = GPIO_I2C1_SDA,
#ifndef CONFIG_I2C_SLAVE
.mode = I2C_MASTER,
#else
.mode = I2C_SLAVE,
#endif
#ifndef CONFIG_I2C_POLLED
.irq = AM335X_IRQ_I2C1,
#endif
};
static struct am335x_i2c_priv_s am335x_i2c1_priv =
{
.ops = &am335x_i2c_ops,
.config = &am335x_i2c1_config,
.refs = 0,
.lock = NXMUTEX_INITIALIZER,
#ifndef CONFIG_I2C_POLLED
.sem_isr = SEM_INITIALIZER(0),
#endif
.intstate = INTSTATE_IDLE,
.msgc = 0,
.msgv = NULL,
.ptr = NULL,
.dcnt = 0,
.flags = 0,
.status = 0
};
#endif
#ifdef CONFIG_AM335X_I2C2
static const struct am335x_i2c_config_s am335x_i2c2_config =
{
.base = AM335X_I2C2_VADDR,
.scl_pin = GPIO_I2C2_SCL,
.sda_pin = GPIO_I2C2_SDA,
#ifndef CONFIG_I2C_SLAVE
.mode = I2C_MASTER,
#else
.mode = I2C_SLAVE,
#endif
#ifndef CONFIG_I2C_POLLED
.irq = AM335X_IRQ_I2C2,
#endif
};
static struct am335x_i2c_priv_s am335x_i2c2_priv =
{
.ops = &am335x_i2c_ops,
.config = &am335x_i2c2_config,
.refs = 0,
.lock = NXMUTEX_INITIALIZER,
#ifndef CONFIG_I2C_POLLED
.sem_isr = SEM_INITIALIZER(0),
#endif
.intstate = INTSTATE_IDLE,
.msgc = 0,
.msgv = NULL,
.ptr = NULL,
.dcnt = 0,
.flags = 0,
.status = 0
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: am335x_i2c_getreg
*
* Description:
* Get a 32-bit register value by offset
*
****************************************************************************/
static inline uint32_t am335x_i2c_getreg(struct am335x_i2c_priv_s *priv,
uint16_t offset)
{
return getreg32(priv->config->base + offset);
}
/****************************************************************************
* Name: am335x_i2c_putreg
*
* Description:
* Put a 32-bit register value by offset
*
****************************************************************************/
static inline void am335x_i2c_putreg(struct am335x_i2c_priv_s *priv,
uint16_t offset, uint32_t value)
{
putreg32(value, priv->config->base + offset);
}
/****************************************************************************
* Name: am335x_i2c_modifyreg
*
* Description:
* Modify a 32-bit register value by offset
*
****************************************************************************/
static inline void am335x_i2c_modifyreg(struct am335x_i2c_priv_s *priv,
uint16_t offset, uint32_t clearbits,
uint32_t setbits)
{
modifyreg32(priv->config->base + offset, clearbits, setbits);
}
/****************************************************************************
* Name: am335x_i2c_toticks
*
* Description:
* Return a micro-second delay based on the number of bytes left to be
* processed.
*
****************************************************************************/
#ifdef CONFIG_AM335X_I2C_DYNTIMEO
static uint32_t am335x_i2c_toticks(int msgc, struct i2c_msg_s *msgs)
{
size_t bytecount = 0;
int i;
/* Count the number of bytes left to process */
for (i = 0; i < msgc; i++)
{
bytecount += msgs[i].length;
}
/* Then return a number of microseconds based on a user provided scaling
* factor.
*/
return USEC2TICK(CONFIG_AM335X_I2C_DYNTIMEO_USECPERBYTE * bytecount);
}
#endif
/****************************************************************************
* Name: am335x_i2c_sem_waitdone
*
* Description:
* Wait for a transfer to complete
*
****************************************************************************/
#ifndef CONFIG_I2C_POLLED
static inline int am335x_i2c_sem_waitdone(struct am335x_i2c_priv_s *priv)
{
irqstate_t flags;
uint32_t regval;
int ret;
flags = enter_critical_section();
/* Enable Interrupts when master mode */
if (priv->config->mode == I2C_MASTER)
{
if ((priv->flags & I2C_M_READ) != 0)
{
regval = I2C_IRQ_AL | I2C_IRQ_NACK | I2C_IRQ_RRDY
| I2C_IRQ_XRDY | I2C_IRQ_AERR | I2C_IRQ_BF;
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_SET_OFFSET, regval);
}
else
{
regval = I2C_IRQ_AL | I2C_IRQ_NACK | I2C_IRQ_XRDY
| I2C_IRQ_AERR | I2C_IRQ_BF;
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_SET_OFFSET, regval);
}
/* Force generate bus free interrupt to start transmission */
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_STAT_RAW_OFFSET, I2C_IRQ_BF);
}
/* Enable Interrupts when slave mode */
else
{
#warning Missing logic for I2C Slave mode
}
/* Signal the interrupt handler that we are waiting. NOTE: Interrupts
* are currently disabled but will be temporarily re-enabled below when
* nxsem_tickwait() sleeps.
*/
priv->intstate = INTSTATE_WAITING;
do
{
/* Wait until either the transfer is complete or the timeout expires */
#ifdef CONFIG_AM335X_I2C_DYNTIMEO
ret = nxsem_tickwait(&priv->sem_isr,
am335x_i2c_toticks(priv->msgc, priv->msgv));
#else
ret = nxsem_tickwait(&priv->sem_isr,
CONFIG_AM335X_I2CTIMEOTICKS);
#endif
if (ret < 0 && ret != -EINTR)
{
/* Break out of the loop on irrecoverable errors. This would
* include timeouts and mystery errors reported by nxsem_tickwait.
* NOTE that we try again if we are awakened by a signal (EINTR).
*/
break;
}
}
/* Loop until the interrupt level transfer is complete. */
while (priv->intstate != INTSTATE_DONE);
/* Set the interrupt state back to IDLE */
priv->intstate = INTSTATE_IDLE;
/* Disable I2C interrupts */
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_CLR_OFFSET, I2C_ICR_CLEARMASK);
leave_critical_section(flags);
return ret;
}
#else
static inline int am335x_i2c_sem_waitdone(struct am335x_i2c_priv_s *priv)
{
clock_t timeout;
clock_t start;
clock_t elapsed;
int ret;
/* Get the timeout value */
#ifdef CONFIG_AM335X_I2C_DYNTIMEO
timeout = am335x_i2c_toticks(priv->msgc, priv->msgv);
#else
timeout = CONFIG_AM335X_I2CTIMEOTICKS;
#endif
priv->intstate = INTSTATE_WAITING;
start = clock_systime_ticks();
do
{
/* Calculate the elapsed time */
elapsed = clock_systime_ticks() - start;
/* Poll by simply calling the timer interrupt handler until it
* reports that it is done.
*/
am335x_i2c_isr_process(priv);
}
/* Loop until the transfer is complete. */
while (priv->intstate != INTSTATE_DONE && elapsed < timeout);
i2cinfo("intstate: %d elapsed: %ld threshold: %ld status: %08x\n",
priv->intstate, (long)elapsed, (long)timeout, priv->status);
/* Set the interrupt state back to IDLE */
ret = priv->intstate == INTSTATE_DONE ? OK : -ETIMEDOUT;
priv->intstate = INTSTATE_IDLE;
return ret;
}
#endif
/****************************************************************************
* Name: am335x_i2c_sem_waitstop
*
* Description:
* Wait for a STOP to complete
*
****************************************************************************/
static inline bool
am335x_i2c_sem_waitstop(struct am335x_i2c_priv_s *priv)
{
clock_t start;
clock_t elapsed;
clock_t timeout;
uint32_t regval;
/* Select a timeout */
#ifdef CONFIG_AM335X_I2C_DYNTIMEO
timeout = USEC2TICK(CONFIG_AM335X_I2C_DYNTIMEO_STARTSTOP);
#else
timeout = CONFIG_AM335X_I2CTIMEOTICKS;
#endif
/* Wait as stop might still be in progress; but stop might also
* be set because of a timeout error: "The [STOP] bit is set and
* cleared by software, cleared by hardware when a Stop condition is
* detected, set by hardware when a timeout error is detected."
*/
start = clock_systime_ticks();
do
{
/* Calculate the elapsed time */
elapsed = clock_systime_ticks() - start;
/* Check for Bus Free condition */
regval = am335x_i2c_getreg(priv, AM335X_I2C_IRQ_STAT_RAW_OFFSET);
if ((regval & I2C_IRQ_BB) == 0)
{
return true;
}
}
/* Loop until the stop is complete or a timeout occurs. */
while (elapsed < timeout);
/* If we get here then a timeout occurred with the STOP condition
* still pending.
*/
i2cinfo("Timeout with Status Register: %x\n", regval);
return false;
}
/****************************************************************************
* Name: am335x_i2c_trace*
*
* Description:
* I2C trace instrumentation
*
****************************************************************************/
#ifdef CONFIG_I2C_TRACE
static void am335x_i2c_traceclear(struct am335x_i2c_priv_s *priv)
{
struct am335x_trace_s *trace = &priv->trace[priv->tndx];
trace->status = 0; /* I2C 32-bit SR2|SR1 status */
trace->count = 0; /* Interrupt count when status change */
trace->event = I2CEVENT_NONE; /* Last event that occurred with this status */
trace->parm = 0; /* Parameter associated with the event */
trace->time = 0; /* Time of first status or event */
}
static void am335x_i2c_tracereset(struct am335x_i2c_priv_s *priv)
{
/* Reset the trace info for a new data collection */
priv->tndx = 0;
priv->start_time = clock_systime_ticks();
am335x_i2c_traceclear(priv);
}
static void am335x_i2c_tracenew(struct am335x_i2c_priv_s *priv,
uint32_t status)
{
struct am335x_trace_s *trace = &priv->trace[priv->tndx];
/* Is the current entry uninitialized? Has the status changed? */
if (trace->count == 0 || status != trace->status)
{
/* Yes.. Was it the status changed? */
if (trace->count != 0)
{
/* Yes.. bump up the trace index (unless out of trace entries) */
if (priv->tndx >= (CONFIG_I2C_NTRACE - 1))
{
i2cerr("ERROR: Trace table overflow\n");
return;
}
priv->tndx++;
trace = &priv->trace[priv->tndx];
}
/* Initialize the new trace entry */
am335x_i2c_traceclear(priv);
trace->status = status;
trace->count = 1;
trace->time = clock_systime_ticks();
}
else
{
/* Just increment the count of times that we have seen this status */
trace->count++;
}
}
static void am335x_i2c_traceevent(struct am335x_i2c_priv_s *priv,
enum am335x_trace_e event, uint32_t parm)
{
struct am335x_trace_s *trace;
if (event != I2CEVENT_NONE)
{
trace = &priv->trace[priv->tndx];
/* Initialize the new trace entry */
trace->event = event;
trace->parm = parm;
/* Bump up the trace index (unless we are out of trace entries) */
if (priv->tndx >= (CONFIG_I2C_NTRACE - 1))
{
i2cerr("ERROR: Trace table overflow\n");
return;
}
priv->tndx++;
am335x_i2c_traceclear(priv);
}
}
static void am335x_i2c_tracedump(struct am335x_i2c_priv_s *priv)
{
struct am335x_trace_s *trace;
int i;
syslog(LOG_DEBUG, "Elapsed time: %ld\n",
(long)(clock_systime_ticks() - priv->start_time));
for (i = 0; i < priv->tndx; i++)
{
trace = &priv->trace[i];
syslog(LOG_DEBUG,
"%2d. STATUS: %08x COUNT: %3d EVENT: %s(%2d) PARM: %08x "
"TIME: %d\n",
i + 1, trace->status, trace->count,
g_trace_names[trace->event],
trace->event, trace->parm, trace->time - priv->start_time);
}
}
#endif /* CONFIG_I2C_TRACE */
/****************************************************************************
* Name: am335x_i2c_setclock
*
* Description:
* Set the I2C clock
*
****************************************************************************/
static void am335x_i2c_setclock(struct am335x_i2c_priv_s *priv,
uint32_t frequency)
{
uint32_t src_freq = AM335X_I2C_SCLK;
uint32_t men;
uint32_t prescale = 0;
uint32_t scl = 0;
uint32_t scl_low = 0;
uint32_t scl_hi = 0;
uint32_t best_prescale = 0;
uint32_t best_scl_low = 0;
uint32_t best_scl_hi = 0;
uint32_t abs_error = 0;
uint32_t best_error = 0xffffffff;
uint32_t computed_rate;
/* Has the I2C bus frequency changed? */
if (priv->config->mode == I2C_MASTER)
{
if (frequency != priv->frequency)
{
/* Disable the selected I2C peripheral to configure the new
* clock if it is enabled.
*/
men = am335x_i2c_getreg(priv, AM335X_I2C_CON_OFFSET) & I2C_CON_EN;
if (men)
{
am335x_i2c_modifyreg(priv, AM335X_I2C_CON_OFFSET,
I2C_CON_EN, 0);
}
/* I2C bus clock is:
* Source Clock (Hz) / ((psc + 1) * (scll + 7 + sclh + 5))
*/
for (scl = 14; scl < 522; scl += 2)
{
for (prescale = 3; prescale < 256; prescale++)
{
scl_low = (scl / 2) - 7;
scl_hi = (scl / 2) - 5;
computed_rate = src_freq / (prescale + 1);
computed_rate /= scl_low + 7 + scl_hi + 5;
if (frequency > computed_rate)
{
abs_error = frequency - computed_rate;
}
else
{
abs_error = computed_rate - frequency;
}
if (abs_error < best_error)
{
best_prescale = prescale;
best_scl_low = scl_low;
best_scl_hi = scl_hi;
best_error = abs_error;
if (abs_error == 0)
{
scl = 522;
break;
}
}
}
}
am335x_i2c_putreg(priv, AM335X_I2C_PSC_OFFSET, best_prescale);
am335x_i2c_putreg(priv, AM335X_I2C_SCLL_OFFSET, best_scl_low);
am335x_i2c_putreg(priv, AM335X_I2C_SCLH_OFFSET, best_scl_hi);
/* Re-enable I2C if it was enabled previously */
if (men)
{
am335x_i2c_modifyreg(priv, AM335X_I2C_CON_OFFSET,
0, I2C_CON_EN);
}
/* Save the new I2C frequency */
priv->frequency = frequency;
}
}
}
/****************************************************************************
* Name: am335x_i2c_sendstart
*
* Description:
* Send the START conditions/force Master mode
*
****************************************************************************/
static inline void am335x_i2c_sendstart(struct am335x_i2c_priv_s *priv,
uint16_t address)
{
uint32_t regval;
/* Generate START condition and send the address */
regval = am335x_i2c_getreg(priv, AM335X_I2C_CON_OFFSET) | I2C_CON_STT |
I2C_CON_MST;
if ((priv->flags & I2C_M_READ) != 0)
{
regval &= ~I2C_CON_TRX;
}
else
{
regval |= I2C_CON_TRX;
}
if ((priv->flags & I2C_M_TEN) != 0)
{
regval |= I2C_CON_XSA;
}
else
{
regval &= ~I2C_CON_XSA;
}
am335x_i2c_putreg(priv, AM335X_I2C_SA_OFFSET, address);
am335x_i2c_putreg(priv, AM335X_I2C_CON_OFFSET, regval);
}
/****************************************************************************
* Name: am335x_i2c_sendstop
*
* Description:
* Send the STOP conditions
*
****************************************************************************/
static inline void am335x_i2c_sendstop(struct am335x_i2c_priv_s *priv)
{
am335x_i2c_modifyreg(priv, AM335X_I2C_CON_OFFSET, 0, I2C_CON_STP);
}
/****************************************************************************
* Name: am335x_i2c_getstatus
*
* Description:
* Get 32-bit status
*
****************************************************************************/
static inline uint32_t
am335x_i2c_getstatus(struct am335x_i2c_priv_s *priv)
{
#ifndef CONFIG_I2C_POLLED
return am335x_i2c_getreg(priv, AM335X_I2C_IRQ_STAT_OFFSET);
#else
return am335x_i2c_getreg(priv, AM335X_I2C_IRQ_STAT_RAW_OFFSET);
#endif
}
/****************************************************************************
* Name: am335x_i2c_isr_process
*
* Description:
* Common Interrupt Service Routine
*
****************************************************************************/
static int am335x_i2c_isr_process(struct am335x_i2c_priv_s *priv)
{
uint32_t status = am335x_i2c_getstatus(priv);
/* Check for new trace setup */
am335x_i2c_tracenew(priv, status);
/* Continue with either sending or reading data */
/* Check if there is more bytes to send */
if (((priv->flags & I2C_M_READ) == 0) && (status & I2C_IRQ_XRDY) != 0)
{
if (priv->dcnt > 0)
{
am335x_i2c_traceevent(priv, I2CEVENT_SENDBYTE, priv->dcnt);
/* No interrupts or context switches should occur in the following
* sequence. Otherwise, additional bytes may be sent by the device.
*/
#ifdef CONFIG_I2C_POLLED
irqstate_t flags = enter_critical_section();
#endif
/* Transmit a byte */
am335x_i2c_putreg(priv, AM335X_I2C_DATA_OFFSET, *priv->ptr++);
priv->dcnt--;
#ifdef CONFIG_I2C_POLLED
leave_critical_section(flags);
#endif
if ((priv->dcnt == 0) && ((priv->flags & I2C_M_NOSTOP) == 0))
{
am335x_i2c_sendstop(priv);
}
}
}
/* Check if there is more bytes to read */
else if (((priv->flags & I2C_M_READ) != 0) && (status & I2C_IRQ_RRDY) != 0)
{
/* Read a byte, if dcnt goes < 0, then read dummy bytes to ack ISRs */
if (priv->dcnt > 0)
{
am335x_i2c_traceevent(priv, I2CEVENT_RCVBYTE, priv->dcnt);
/* No interrupts or context switches should occur in the following
* sequence. Otherwise, additional bytes may be received by the
* device.
*/
#ifdef CONFIG_I2C_POLLED
irqstate_t flags = enter_critical_section();
#endif
/* Receive a byte */
*priv->ptr++ = am335x_i2c_getreg(priv, AM335X_I2C_DATA_OFFSET) &
I2C_DATA_MASK;
priv->dcnt--;
#ifdef CONFIG_I2C_POLLED
leave_critical_section(flags);
#endif
if ((priv->msgc <= 0) && (priv->dcnt == 0))
{
am335x_i2c_sendstop(priv);
}
}
else
{
am335x_i2c_getreg(priv, AM335X_I2C_DATA_OFFSET);
}
}
if (priv->dcnt <= 0)
{
if (priv->msgc > 0 && priv->msgv != NULL)
{
priv->ptr = priv->msgv->buffer;
priv->dcnt = priv->msgv->length;
priv->flags = priv->msgv->flags;
if ((priv->flags & I2C_M_NOSTART) == 0)
{
am335x_i2c_traceevent(priv, I2CEVENT_STARTRESTART, priv->msgc);
am335x_i2c_sendstart(priv, priv->msgv->addr);
}
else
{
am335x_i2c_traceevent(priv, I2CEVENT_NOSTART, priv->msgc);
}
priv->msgv++;
priv->msgc--;
if ((priv->flags & I2C_M_READ) != 0)
{
#ifndef CONFIG_I2C_POLLED
/* Stop TX interrupt */
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_CLR_OFFSET,
I2C_IRQ_XRDY);
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_SET_OFFSET,
I2C_IRQ_RRDY);
#endif
/* Set I2C in read mode */
am335x_i2c_modifyreg(priv, AM335X_I2C_CON_OFFSET,
I2C_CON_TRX, 0);
am335x_i2c_putreg(priv, AM335X_I2C_CNT_OFFSET, priv->dcnt);
}
else
{
/* Send the first byte from tx buffer */
am335x_i2c_traceevent(priv, I2CEVENT_SENDBYTE, priv->dcnt);
am335x_i2c_modifyreg(priv, AM335X_I2C_CON_OFFSET,
0, I2C_CON_TRX);
/* No interrupts or context switches should occur in the
* following sequence. Otherwise, additional bytes may be sent
* by the device.
*/
#ifdef CONFIG_I2C_POLLED
irqstate_t flags = enter_critical_section();
#endif
/* Transmit a byte */
am335x_i2c_putreg(priv, AM335X_I2C_DATA_OFFSET, *priv->ptr++);
priv->dcnt--;
#ifdef CONFIG_I2C_POLLED
leave_critical_section(flags);
#endif
if ((priv->dcnt == 0) && ((priv->flags & I2C_M_NOSTOP) == 0))
{
am335x_i2c_sendstop(priv);
}
}
}
else if (priv->msgv && ((status & I2C_IRQ_BF) != 0))
{
am335x_i2c_traceevent(priv, I2CEVENT_STOP, 0);
/* Check is there thread waiting for this event (there should be) */
#ifndef CONFIG_I2C_POLLED
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_CLR_OFFSET,
I2C_ICR_CLEARMASK);
if (priv->intstate == INTSTATE_WAITING)
{
/* inform the thread that transfer is complete
* and wake it up
*/
nxsem_post(&priv->sem_isr);
priv->intstate = INTSTATE_DONE;
}
#else
priv->intstate = INTSTATE_DONE;
#endif
/* Mark that this transaction stopped */
priv->msgv = NULL;
}
#ifndef CONFIG_I2C_POLLED
else
{
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_CLR_OFFSET,
I2C_IRQ_XRDY | I2C_IRQ_RRDY);
}
#endif
}
/* Check for errors */
if ((status & I2C_IRQ_ERRORMASK) != 0)
{
am335x_i2c_traceevent(priv, I2CEVENT_ERROR, 0);
#ifndef CONFIG_I2C_POLLED
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_CLR_OFFSET,
I2C_ICR_CLEARMASK);
if (priv->intstate == INTSTATE_WAITING)
{
/* inform the thread that transfer is complete
* and wake it up
*/
nxsem_post(&priv->sem_isr);
priv->intstate = INTSTATE_DONE;
}
#else
priv->intstate = INTSTATE_DONE;
#endif
}
/* Clear interrupt status */
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_STAT_OFFSET, status);
priv->status = status;
return OK;
}
/****************************************************************************
* Name: am335x_i2c_isr
*
* Description:
* Common I2C interrupt service routine
*
****************************************************************************/
#ifndef CONFIG_I2C_POLLED
static int am335x_i2c_isr(int irq, void *context, void *arg)
{
struct am335x_i2c_priv_s *priv = (struct am335x_i2c_priv_s *)arg;
DEBUGASSERT(priv != NULL);
return am335x_i2c_isr_process(priv);
}
#endif
/****************************************************************************
* Name: am335x_i2c_init
*
* Description:
* Setup the I2C hardware, ready for operation with defaults
*
****************************************************************************/
static int am335x_i2c_init(struct am335x_i2c_priv_s *priv)
{
/* Power-up and configure GPIOs */
/* Configure pins */
am335x_gpio_config(priv->config->scl_pin);
am335x_gpio_config(priv->config->sda_pin);
/* Disable I2C module */
am335x_i2c_putreg(priv, AM335X_I2C_CON_OFFSET, 0);
/* Apply soft reset */
am335x_i2c_putreg(priv, AM335X_I2C_SYSC_OFFSET, I2C_SYSC_SRST);
/* Disable auto-idle mode */
am335x_i2c_modifyreg(priv, AM335X_I2C_SYSC_OFFSET, I2C_SYSC_AUTOIDLE, 0);
/* Force a frequency update */
priv->frequency = 0;
am335x_i2c_setclock(priv, 100000);
#ifndef CONFIG_I2C_POLLED
/* Attach ISRs */
irq_attach(priv->config->irq, am335x_i2c_isr, priv);
up_enable_irq(priv->config->irq);
#endif
/* Enable I2C module */
am335x_i2c_modifyreg(priv, AM335X_I2C_CON_OFFSET, 0, I2C_CON_EN);
/* Select free running mode */
am335x_i2c_modifyreg(priv, AM335X_I2C_SYSTEST_OFFSET, 0, I2C_SYSTEST_FREE);
/* Wait for I2C module comes out of reset */
while (!(am335x_i2c_getreg(priv, AM335X_I2C_SYSS_OFFSET) &
I2C_SYSS_RST_DONE))
{
}
return OK;
}
/****************************************************************************
* Name: am335x_i2c_deinit
*
* Description:
* Shutdown the I2C hardware
*
****************************************************************************/
static int am335x_i2c_deinit(struct am335x_i2c_priv_s *priv)
{
/* Disable I2C module */
am335x_i2c_putreg(priv, AM335X_I2C_CON_OFFSET, 0);
/* Apply soft reset */
am335x_i2c_putreg(priv, AM335X_I2C_SYSC_OFFSET, I2C_SYSC_SRST);
/* Disable and detach interrupts */
#ifndef CONFIG_I2C_POLLED
up_disable_irq(priv->config->irq);
irq_detach(priv->config->irq);
#endif
return OK;
}
/****************************************************************************
* Device Driver Operations
****************************************************************************/
/****************************************************************************
* Name: am335x_i2c_transfer
*
* Description:
* Generic I2C transfer function
*
****************************************************************************/
static int am335x_i2c_transfer(struct i2c_master_s *dev,
struct i2c_msg_s *msgs, int count)
{
struct am335x_i2c_priv_s *priv = (struct am335x_i2c_priv_s *)dev;
int ret;
DEBUGASSERT(count > 0);
/* Ensure that address or flags don't change meanwhile */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
return ret;
}
/* Wait for any STOP in progress */
ret = -EBUSY;
if (am335x_i2c_sem_waitstop(priv))
{
/* Clear any pending error interrupts */
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_STAT_OFFSET,
I2C_STS_CLEARMASK);
am335x_i2c_putreg(priv, AM335X_I2C_IRQ_EN_CLR_OFFSET,
I2C_ICR_CLEARMASK);
/* Old transfers are done */
/* Reset ptr and dcnt to ensure an unexpected data interrupt doesn't
* overwrite stale data.
*/
priv->dcnt = 0;
priv->ptr = NULL;
priv->msgv = msgs;
priv->msgc = count;
priv->flags = msgs->flags;
i2cinfo("Flags %x, len %d\n", msgs->flags, msgs->length);
/* Reset I2C trace logic */
am335x_i2c_tracereset(priv);
/* Set I2C clock frequency */
am335x_i2c_setclock(priv, msgs->frequency);
priv->status = 0;
/* Wait for an ISR, if there was a timeout, fetch latest status to get
* the BUSY flag.
*/
if (am335x_i2c_sem_waitdone(priv) < 0)
{
ret = -ETIMEDOUT;
i2cerr("ERROR: Timed out: IRQ_RAW: status: 0x%x\n", priv->status);
}
/* Check for error status conditions */
else if ((priv->status & I2C_IRQ_ERRORMASK) != 0)
{
/* I2C_IRQ_ERRORMASK is the OR of the following individual bits: */
if (priv->status & I2C_IRQ_AL)
{
/* Arbitration Lost (master mode) */
i2cerr("Arbitration lost\n");
ret = -EAGAIN;
}
else if (priv->status & I2C_IRQ_NACK)
{
/* Acknowledge Failure */
i2cerr("Ack failure\n");
ret = -ENXIO;
}
else if (priv->status & (I2C_IRQ_XUDF | I2C_IRQ_ROVR))
{
/* Overrun/Underrun */
i2cerr("Overrun/Underrun status\n");
ret = -EIO;
}
else if (priv->status & I2C_IRQ_AERR)
{
/* Access Error in reception or transmission */
i2cerr("Access Error\n");
ret = -EPROTO;
}
else if (priv->status & I2C_IRQ_BB)
{
/* Bus busy Error */
i2cerr("Bus busy error\n");
ret = -EIO;
}
else
{
i2cerr("Unspecified error\n");
ret = -EINTR;
}
}
else
{
ret = OK;
}
/* Dump the trace result */
am335x_i2c_tracedump(priv);
/* Ensure ISR happening after we finish can't overwrite any user data */
priv->dcnt = 0;
priv->ptr = NULL;
}
nxmutex_unlock(&priv->lock);
return ret;
}
/****************************************************************************
* Name: am335x_i2c_reset
*
* Description:
* Perform an I2C bus reset in an attempt to break loose stuck I2C devices.
*
* Input Parameters:
* dev - Device-specific state data
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
#ifdef CONFIG_I2C_RESET
static int am335x_i2c_reset(struct i2c_master_s *dev)
{
struct am335x_i2c_priv_s *priv = (struct am335x_i2c_priv_s *)dev;
unsigned int clock_count;
unsigned int stretch_count;
gpio_pinset_t scl_gpio;
gpio_pinset_t sda_gpio;
uint32_t frequency;
int ret;
DEBUGASSERT(dev);
/* Our caller must own a ref */
DEBUGASSERT(priv->refs > 0);
/* Lock out other clients */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
return ret;
}
ret = -EIO;
/* Save the current frequency */
frequency = priv->frequency;
/* De-init the port */
am335x_i2c_deinit(priv);
/* Use GPIO configuration to un-wedge the bus */
scl_gpio = MKI2C_OUTPUT(priv->config->scl_pin);
sda_gpio = MKI2C_OUTPUT(priv->config->sda_pin);
am335x_gpio_config(scl_gpio);
am335x_gpio_config(sda_gpio);
/* Let SDA go high */
am335x_gpio_write(sda_gpio, 1);
/* Clock the bus until any slaves currently driving it let it go. */
clock_count = 0;
while (!am335x_gpio_read(sda_gpio))
{
/* Give up if we have tried too hard */
if (clock_count++ > 10)
{
goto out;
}
/* Sniff to make sure that clock stretching has finished.
*
* If the bus never relaxes, the reset has failed.
*/
stretch_count = 0;
while (!am335x_gpio_read(scl_gpio))
{
/* Give up if we have tried too hard */
if (stretch_count++ > 10)
{
goto out;
}
up_udelay(10);
}
/* Drive SCL low */
am335x_gpio_write(scl_gpio, 0);
up_udelay(10);
/* Drive SCL high again */
am335x_gpio_write(scl_gpio, 1);
up_udelay(10);
}
/* Generate a start followed by a stop to reset slave
* state machines.
*/
am335x_gpio_write(sda_gpio, 0);
up_udelay(10);
am335x_gpio_write(scl_gpio, 0);
up_udelay(10);
am335x_gpio_write(scl_gpio, 1);
up_udelay(10);
am335x_gpio_write(sda_gpio, 1);
up_udelay(10);
/* Re-init the port */
am335x_i2c_init(priv);
/* Restore the frequency */
am335x_i2c_setclock(priv, frequency);
ret = OK;
out:
/* Release the port for re-use by other clients */
nxmutex_unlock(&priv->lock);
return ret;
}
#endif /* CONFIG_I2C_RESET */
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: am335x_i2cbus_initialize
*
* Description:
* Initialize one I2C bus
*
****************************************************************************/
struct i2c_master_s *am335x_i2cbus_initialize(int port)
{
struct am335x_i2c_priv_s *priv = NULL;
/* Get I2C private structure */
switch (port)
{
#ifdef CONFIG_AM335X_I2C0
case 0:
priv = (struct am335x_i2c_priv_s *)&am335x_i2c0_priv;
break;
#endif
#ifdef CONFIG_AM335X_I2C1
case 1:
priv = (struct am335x_i2c_priv_s *)&am335x_i2c1_priv;
break;
#endif
#ifdef CONFIG_AM335X_I2C2
case 2:
priv = (struct am335x_i2c_priv_s *)&am335x_i2c2_priv;
break;
#endif
default:
return NULL;
}
/* Initialize private data for the first time, increment reference count,
* power-up hardware and configure GPIOs.
*/
nxmutex_lock(&priv->lock);
if (priv->refs++ == 0)
{
am335x_i2c_init(priv);
}
nxmutex_unlock(&priv->lock);
return (struct i2c_master_s *)priv;
}
/****************************************************************************
* Name: am335x_i2cbus_uninitialize
*
* Description:
* Uninitialize an I2C bus
*
****************************************************************************/
int am335x_i2cbus_uninitialize(struct i2c_master_s *dev)
{
struct am335x_i2c_priv_s *priv = (struct am335x_i2c_priv_s *)dev;
DEBUGASSERT(dev);
/* Decrement reference count and check for underflow */
if (priv->refs == 0)
{
return ERROR;
}
nxmutex_lock(&priv->lock);
if (--priv->refs > 0)
{
nxmutex_unlock(&priv->lock);
return OK;
}
/* Disable power and other HW resource (GPIO's) */
am335x_i2c_deinit(priv);
nxmutex_unlock(&priv->lock);
return OK;
}
#endif /* CONFIG_AM335X_I2C0 || CONFIG_AM335X_I2C1 || \
* CONFIG_AM335X_I2C2 */