source: rtems/c/src/lib/libbsp/arm/beagle/include/i2c.h @ 53dd6d61

/**
 * @file
 *
 * @ingroup arm_beagle
 *
 * @brief I2C support API.
 */

/*
 * Copyright (c) 2012 Claas Ziemke. All rights reserved.
 *
 *  Claas Ziemke
 *  Kernerstrasse 11
 *  70182 Stuttgart
 *  Germany
 *  <claas.ziemke@gmx.net>
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.com/license/LICENSE.
 */

#ifndef LIBBSP_ARM_BEAGLE_I2C_H
#define LIBBSP_ARM_BEAGLE_I2C_H

#include <rtems.h>

#include <bsp.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */


/* I2C Configuration Register (I2C_CON): */

#define I2C_CON_EN  (1 << 15)  /* I2C module enable */
#define I2C_CON_BE  (1 << 14)  /* Big endian mode */
#define I2C_CON_STB (1 << 11)  /* Start byte mode (master mode only) */
#define I2C_CON_MST (1 << 10)  /* Master/slave mode */
#define I2C_CON_TRX (1 << 9)   /* Transmitter/receiver mode */
           /* (master mode only) */
#define I2C_CON_XA  (1 << 8)   /* Expand address */
#define I2C_CON_STP (1 << 1)   /* Stop condition (master mode only) */
#define I2C_CON_STT (1 << 0)   /* Start condition (master mode only) */

/* I2C Status Register (I2C_STAT): */

#define I2C_STAT_SBD  (1 << 15) /* Single byte data */
#define I2C_STAT_BB (1 << 12) /* Bus busy */
#define I2C_STAT_ROVR (1 << 11) /* Receive overrun */
#define I2C_STAT_XUDF (1 << 10) /* Transmit underflow */
#define I2C_STAT_AAS  (1 << 9)  /* Address as slave */
#define I2C_STAT_GC (1 << 5)
#define I2C_STAT_XRDY (1 << 4)  /* Transmit data ready */
#define I2C_STAT_RRDY (1 << 3)  /* Receive data ready */
#define I2C_STAT_ARDY (1 << 2)  /* Register access ready */
#define I2C_STAT_NACK (1 << 1)  /* No acknowledgment interrupt enable */
#define I2C_STAT_AL (1 << 0)  /* Arbitration lost interrupt enable */

/* I2C Interrupt Enable Register (I2C_IE): */
#define I2C_IE_GC_IE  (1 << 5)
#define I2C_IE_XRDY_IE  (1 << 4) /* Transmit data ready interrupt enable */
#define I2C_IE_RRDY_IE  (1 << 3) /* Receive data ready interrupt enable */
#define I2C_IE_ARDY_IE  (1 << 2) /* Register access ready interrupt enable */
#define I2C_IE_NACK_IE  (1 << 1) /* No acknowledgment interrupt enable */
#define I2C_IE_AL_IE  (1 << 0) /* Arbitration lost interrupt enable */
/*
 * The equation for the low and high time is
 * tlow = scll + scll_trim = (sampling clock * tlow_duty) / speed
 * thigh = sclh + sclh_trim = (sampling clock * (1 - tlow_duty)) / speed
 *
 * If the duty cycle is 50%
 *
 * tlow = scll + scll_trim = sampling clock / (2 * speed)
 * thigh = sclh + sclh_trim = sampling clock / (2 * speed)
 *
 * In TRM
 * scll_trim = 7
 * sclh_trim = 5
 *
 * The linux 2.6.30 kernel uses
 * scll_trim = 6
 * sclh_trim = 6
 *
 * These are the trim values for standard and fast speed
 */
#ifndef I2C_FASTSPEED_SCLL_TRIM
#define I2C_FASTSPEED_SCLL_TRIM   6
#endif
#ifndef I2C_FASTSPEED_SCLH_TRIM
#define I2C_FASTSPEED_SCLH_TRIM   6
#endif

/* These are the trim values for high speed */
#ifndef I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM
#define I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM
#endif
#ifndef I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM
#define I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM
#endif
#ifndef I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM
#define I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM I2C_FASTSPEED_SCLL_TRIM
#endif
#ifndef I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM
#define I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM I2C_FASTSPEED_SCLH_TRIM
#endif

#define OMAP_I2C_STANDARD 100000
#define OMAP_I2C_FAST_MODE  400000
#define OMAP_I2C_HIGH_SPEED 3400000


/* Use the reference value of 96MHz if not explicitly set by the board */
#ifndef I2C_IP_CLK
#define I2C_IP_CLK    SYSTEM_CLOCK_96
#endif

/*
 * The reference minimum clock for high speed is 19.2MHz.
 * The linux 2.6.30 kernel uses this value.
 * The reference minimum clock for fast mode is 9.6MHz
 * The reference minimum clock for standard mode is 4MHz
 * In TRM, the value of 12MHz is used.
 */
#ifndef I2C_INTERNAL_SAMPLING_CLK
#define I2C_INTERNAL_SAMPLING_CLK 19200000
#endif

#define I2C_PSC_MAX   0x0f
#define I2C_PSC_MIN   0x00


#define DISP_LINE_LEN 128
#define I2C_TIMEOUT 1000

#define I2C_BUS_MAX 3

#define I2C_BASE1         (OMAP34XX_CORE_L4_IO_BASE + 0x070000)

#define I2C_DEFAULT_BASE      I2C_BASE1

#define I2C_SYSS_RDONE            (1 << 0)  /* Internel reset monitoring */

#define CONFIG_SYS_I2C_SPEED    100000
#define CONFIG_SYS_I2C_SLAVE    1

struct i2c {
  unsigned short rev;   /* 0x00 */
  unsigned short res1;
  unsigned short ie;    /* 0x04 */
  unsigned short res2;
  unsigned short stat;  /* 0x08 */
  unsigned short res3;
  unsigned short iv;    /* 0x0C */
  unsigned short res4;
  unsigned short syss;  /* 0x10 */
  unsigned short res4a;
  unsigned short buf;   /* 0x14 */
  unsigned short res5;
  unsigned short cnt;   /* 0x18 */
  unsigned short res6;
  unsigned short data;  /* 0x1C */
  unsigned short res7;
  unsigned short sysc;  /* 0x20 */
  unsigned short res8;
  unsigned short con;   /* 0x24 */
  unsigned short res9;
  unsigned short oa;    /* 0x28 */
  unsigned short res10;
  unsigned short sa;    /* 0x2C */
  unsigned short res11;
  unsigned short psc;   /* 0x30 */
  unsigned short res12;
  unsigned short scll;  /* 0x34 */
  unsigned short res13;
  unsigned short sclh;  /* 0x38 */
  unsigned short res14;
  unsigned short systest; /* 0x3c */
  unsigned short res15;
};

static unsigned short wait_for_pin( void );

static void wait_for_bb( void );

static void flush_fifo( void );

void i2c_init( int speed, int slaveadd );

static int i2c_read_byte(
  unsigned char devaddr,
  unsigned char regoffset,
  unsigned char *value
);

int i2c_write(
  unsigned char chip,
  unsigned int addr,
  int alen,
  unsigned char *buffer,
  int len
);

int i2c_read(
  unsigned char chip,
  uint addr,
  int alen,
  unsigned char *buffer,
  int len
);

static int imw ( unsigned char  chip, unsigned long addr, unsigned char byte );

static int imd( unsigned char chip, unsigned int addr, unsigned int length );

/**
 * @brief Initializes the I2C module @a i2c.
 *
 * Valid @a clock_in_hz values are 100000 and 400000.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_INVALID_ID Invalid @a i2c value.
 * @retval RTEMS_INVALID_CLOCK Invalid @a clock_in_hz value.
 */
rtems_status_code beagle_i2c_init(
  volatile beagle_i2c *i2c,
  unsigned clock_in_hz
);

/**
 * @brief Resets the I2C module @a i2c.
 */
void beagle_i2c_reset(volatile beagle_i2c *i2c);

/**
 * @brief Sets the I2C module @a i2c clock.
 *
 * Valid @a clock_in_hz values are 100000 and 400000.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_INVALID_CLOCK Invalid @a clock_in_hz value.
 */
rtems_status_code beagle_i2c_clock(
  volatile beagle_i2c *i2c,
  unsigned clock_in_hz
);

/**
 * @brief Starts a write transaction on the I2C module @a i2c.
 *
 * The address parameter @a addr must not contain the read/write bit.
 *
 * The error status may be delayed to the next
 * beagle_i2c_write_with_optional_stop() due to controller flaws.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 */
rtems_status_code beagle_i2c_write_start(
  volatile beagle_i2c *i2c,
  unsigned addr
);

/**
 * @brief Writes data via the I2C module @a i2c with optional stop.
 *
 * The error status may be delayed to the next
 * beagle_i2c_write_with_optional_stop() due to controller flaws.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 */
rtems_status_code beagle_i2c_write_with_optional_stop(
  volatile beagle_i2c *i2c,
  const uint8_t *out,
  size_t n,
  bool stop
);

/**
 * @brief Starts a read transaction on the I2C module @a i2c.
 *
 * The address parameter @a addr must not contain the read/write bit.
 *
 * The error status may be delayed to the next
 * beagle_i2c_read_with_optional_stop() due to controller flaws.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 */
rtems_status_code beagle_i2c_read_start(
  volatile beagle_i2c *i2c,
  unsigned addr
);

/**
 * @brief Reads data via the I2C module @a i2c with optional stop.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 * @retval RTEMS_NOT_IMPLEMENTED Stop is @a false.
 */
rtems_status_code beagle_i2c_read_with_optional_stop(
  volatile beagle_i2c *i2c,
  uint8_t *in,
  size_t n,
  bool stop
);

/**
 * @brief Writes and reads data via the I2C module @a i2c.
 *
 * This will be one bus transaction.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 */
rtems_status_code beagle_i2c_write_and_read(
  volatile beagle_i2c *i2c,
  unsigned addr,
  const uint8_t *out,
  size_t out_size,
  uint8_t *in,
  size_t in_size
);

/**
 * @brief Writes data via the I2C module @a i2c.
 *
 * This will be one bus transaction.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 */
static inline rtems_status_code beagle_i2c_write(
  volatile beagle_i2c *i2c,
  unsigned addr,
  const uint8_t *out,
  size_t out_size
)
{
  return beagle_i2c_write_and_read(i2c, addr, out, out_size, NULL, 0);
}

/**
 * @brief Reads data via the I2C module @a i2c.
 *
 * This will be one bus transaction.
 *
 * @retval RTEMS_SUCCESSFUL Successful operation.
 * @retval RTEMS_IO_ERROR Received a NACK from the slave.
 */
static inline rtems_status_code beagle_i2c_read(
  volatile beagle_i2c *i2c,
  unsigned addr,
  uint8_t *in,
  size_t in_size
)
{
  return beagle_i2c_write_and_read(i2c, addr, NULL, 0, in, in_size);
}

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* LIBBSP_ARM_BEAGLE_I2C_H */