/* * MCF5206e MBUS module (I2C bus) driver * * Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia * Author: Victor V. Vengerov * * 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. */ #include "mcf5206/mcfmbus.h" #include "mcf5206/mcf5206e.h" #include "i2c.h" /* Events of I2C machine */ typedef enum i2c_event { EVENT_NONE, /* Spurious event */ EVENT_TRANSFER, /* Start new transfer */ EVENT_NEXTMSG, /* Start processing of next message in transfer */ EVENT_ACK, /* Sending finished with ACK */ EVENT_NACK, /* Sending finished with NACK */ EVENT_TIMEOUT, /* Timeout occured */ EVENT_DATA_RECV, /* Data received */ EVENT_ARB_LOST, /* Arbitration lost */ EVENT_SLAVE /* Addressed as a slave */ } i2c_event; static mcfmbus *mbus; /*** Auxillary primitives ***/ /* Change state of finite state machine */ #define next_state(bus,new_state) \ do { \ (bus)->state = (new_state); \ } while (0) /* Initiate start condition on the I2C bus */ #define mcfmbus_start(bus) \ do { \ *MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_MSTA; \ } while (0) /* Initiate stop condition on the I2C bus */ #define mcfmbus_stop(bus) \ do { \ *MCF5206E_MBCR((bus)->base) &= ~MCF5206E_MBCR_MSTA; \ } while (0) /* Initiate repeat start condition on the I2C bus */ #define mcfmbus_rstart(bus) \ do { \ *MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_RSTA; \ } while (0) /* Send byte to the bus */ #define mcfmbus_send(bus,byte) \ do { \ *MCF5206E_MBDR((bus)->base) = (byte); \ } while (0) /* Set transmit mode */ #define mcfmbus_tx_mode(bus) \ do { \ *MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_MTX; \ } while (0) /* Set receive mode */ #define mcfmbus_rx_mode(bus) \ do { \ *MCF5206E_MBCR((bus)->base) &= ~MCF5206E_MBCR_MTX; \ (void)*MCF5206E_MBDR((bus)->base); \ } while (0) /* Transmit acknowledge when byte received */ #define mcfmbus_send_ack(bus) \ do { \ *MCF5206E_MBCR((bus)->base) &= ~MCF5206E_MBCR_TXAK; \ } while (0) /* DO NOT transmit acknowledge when byte received */ #define mcfmbus_send_nack(bus) \ do { \ *MCF5206E_MBCR((bus)->base) |= MCF5206E_MBCR_TXAK; \ } while (0) #define mcfmbus_error(bus,err_status) \ do { \ do { \ (bus)->cmsg->status = (err_status); \ (bus)->cmsg++; \ } while (((bus)->cmsg - (bus)->msg < (bus)->nmsg) && \ ((bus)->cmsg->flags & I2C_MSG_ERRSKIP)); \ bus->cmsg--; \ } while (0) /* mcfmbus_get_event -- * Read MBUS module status register, determine interrupt reason and * return appropriate event. * * PARAMETERS: * bus - pointer to MBUS module descriptor structure * * RETURNS: * event code */ static i2c_event mcfmbus_get_event(mcfmbus *bus) { i2c_event event; uint8_t status, control; rtems_interrupt_level level; rtems_interrupt_disable(level); status = *MCF5206E_MBSR(bus->base); control = *MCF5206E_MBCR(bus->base); if (status & MCF5206E_MBSR_MIF) /* Interrupt occured */ { if (status & MCF5206E_MBSR_MAAS) { event = EVENT_SLAVE; *MCF5206E_MBCR(bus->base) = control; /* To clear Addressed As Slave condition */ } else if (status & MCF5206E_MBSR_MAL) /* Arbitration lost */ { *MCF5206E_MBSR(bus->base) = status & ~MCF5206E_MBSR_MAL; event = EVENT_ARB_LOST; } else if (control & MCF5206E_MBCR_MTX) /* Trasmit mode */ { if (status & MCF5206E_MBSR_RXAK) event = EVENT_NACK; else event = EVENT_ACK; } else /* Received */ { event = EVENT_DATA_RECV; } /* Clear interrupt condition */ *MCF5206E_MBSR(bus->base) &= ~MCF5206E_MBSR_MIF; } else { event = EVENT_NONE; } rtems_interrupt_enable(level); return event; } static void mcfmbus_machine_error(mcfmbus *bus, i2c_event event) { return; } /* mcfmbus_machine -- * finite state machine for I2C bus protocol * * PARAMETERS: * bus - pointer to ColdFire MBUS descriptor structure * event - I2C event * * RETURNS: * none */ static void mcfmbus_machine(mcfmbus *bus, i2c_event event) { uint8_t b; switch (bus->state) { case STATE_IDLE: switch (event) { case EVENT_NEXTMSG: /* Start new message processing */ bus->cmsg++; /* FALLTHRU */ case EVENT_TRANSFER: /* Initiate new transfer */ if (bus->cmsg - bus->msg >= bus->nmsg) { mcfmbus_stop(bus); next_state(bus, STATE_IDLE); bus->msg = bus->cmsg = NULL; bus->nmsg = bus->byte = 0; bus->done(bus->done_arg_ptr); break; } /* Initiate START or REPEATED START condition on the bus */ if (event == EVENT_TRANSFER) { mcfmbus_start(bus); } else /* (event == EVENT_NEXTMSG) */ { mcfmbus_rstart(bus); } bus->byte = 0; mcfmbus_tx_mode(bus); /* Initiate slave address sending */ if (bus->cmsg->flags & I2C_MSG_ADDR_10) { i2c_address a = bus->cmsg->addr; b = 0xf0 | (((a >> 8) & 0x03) << 1); if (bus->cmsg->flags & I2C_MSG_WR) { mcfmbus_send(bus, b); next_state(bus, STATE_ADDR_1_W); } else { mcfmbus_send(bus, b | 1); next_state(bus, STATE_ADDR_1_R); } } else { b = (bus->cmsg->addr & ~0x01); if (bus->cmsg->flags & I2C_MSG_WR) { next_state(bus, STATE_SENDING); } else { next_state(bus, STATE_ADDR_7); b |= 1; } mcfmbus_send(bus, b); } break; default: mcfmbus_machine_error(bus, event); break; } break; case STATE_ADDR_7: switch (event) { case EVENT_ACK: mcfmbus_rx_mode(bus); if (bus->cmsg->len <= 1) mcfmbus_send_nack(bus); else mcfmbus_send_ack(bus); next_state(bus, STATE_RECEIVING); break; case EVENT_NACK: mcfmbus_error(bus, I2C_NO_DEVICE); next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; case EVENT_ARB_LOST: mcfmbus_error(bus, I2C_ARBITRATION_LOST); next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; default: mcfmbus_machine_error(bus, event); break; } break; case STATE_ADDR_1_R: case STATE_ADDR_1_W: switch (event) { case EVENT_ACK: { uint8_t b = (bus->cmsg->addr & 0xff); mcfmbus_send(bus, b); if (bus->state == STATE_ADDR_1_W) { next_state(bus, STATE_SENDING); } else { i2c_address a; mcfmbus_rstart(bus); mcfmbus_tx_mode(bus); a = bus->cmsg->addr; b = 0xf0 | (((a >> 8) & 0x03) << 1) | 1; mcfmbus_send(bus, b); next_state(bus, STATE_ADDR_7); } break; } case EVENT_NACK: mcfmbus_error(bus, I2C_NO_DEVICE); next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; case EVENT_ARB_LOST: mcfmbus_error(bus, I2C_ARBITRATION_LOST); next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; default: mcfmbus_machine_error(bus, event); break; } break; case STATE_SENDING: switch (event) { case EVENT_ACK: if (bus->byte == bus->cmsg->len) { next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); } else { mcfmbus_send(bus, bus->cmsg->buf[bus->byte++]); next_state(bus, STATE_SENDING); } break; case EVENT_NACK: if (bus->byte == 0) { mcfmbus_error(bus, I2C_NO_DEVICE); } else { mcfmbus_error(bus, I2C_NO_ACKNOWLEDGE); } next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; case EVENT_ARB_LOST: mcfmbus_error(bus, I2C_ARBITRATION_LOST); next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; default: mcfmbus_machine_error(bus, event); break; } break; case STATE_RECEIVING: switch (event) { case EVENT_DATA_RECV: if (bus->cmsg->len - bus->byte <= 2) { mcfmbus_send_nack(bus); if (bus->cmsg->len - bus->byte <= 1) { if (bus->cmsg - bus->msg + 1 == bus->nmsg) mcfmbus_stop(bus); else mcfmbus_rstart(bus); } } else { mcfmbus_send_ack(bus); } bus->cmsg->buf[bus->byte++] = *MCF5206E_MBDR(bus->base); if (bus->cmsg->len == bus->byte) { next_state(bus,STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); } else { next_state(bus,STATE_RECEIVING); } break; case EVENT_ARB_LOST: mcfmbus_error(bus, I2C_ARBITRATION_LOST); next_state(bus, STATE_IDLE); mcfmbus_machine(bus, EVENT_NEXTMSG); break; default: mcfmbus_machine_error(bus, event); break; } break; } } /* mcfmbus_interrupt_handler -- * MBUS module interrupt handler routine * * PARAMETERS: * vector - interrupt vector number (not used) * * RETURNS: * none */ rtems_isr mcfmbus_interrupt_handler(rtems_vector_number vector) { i2c_event event; event = mcfmbus_get_event(mbus); mcfmbus_machine(mbus, event); } /* mcfmbus_poll -- * MBUS module poll routine; used to poll events when I2C driver * operates in poll-driven mode. * * PARAMETERS: * none * * RETURNS: * none */ void mcfmbus_poll(mcfmbus *bus) { i2c_event event; event = mcfmbus_get_event(bus); if (event != EVENT_NONE) mcfmbus_machine(bus, event); } /* mcfmbus_select_clock_divider -- * Select divider for system clock which is used for I2C bus clock * generation. Not each divider can be selected for I2C bus; this * function select nearest larger or equal divider. * * PARAMETERS: * i2c_bus - pointer to the bus descriptor structure * divider - system frequency divider for I2C serial clock. * RETURNS: * RTEMS_SUCCESSFUL, if operation performed successfully, or * RTEMS error code when failed. */ rtems_status_code mcfmbus_select_clock_divider(mcfmbus *i2c_bus, int divider) { int i; int mbc; struct { int divider; int mbc; } dividers[] ={ { 20, 0x20 }, { 22, 0x21 }, { 24, 0x22 }, { 26, 0x23 }, { 28, 0x00 }, { 30, 0x01 }, { 32, 0x25 }, { 34, 0x02 }, { 36, 0x26 }, { 40, 0x03 }, { 44, 0x04 }, { 48, 0x05 }, { 56, 0x06 }, { 64, 0x2a }, { 68, 0x07 }, { 72, 0x2B }, { 80, 0x08 }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A }, { 112, 0x2E }, { 128, 0x0B }, { 144, 0x0C }, { 160, 0x0D }, { 192, 0x0E }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 }, { 288, 0x10 }, { 320, 0x11 }, { 384, 0x12 }, { 448, 0x36 }, { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x15 }, { 768, 0x16 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B }, { 1152, 0x18 }, { 1280, 0x19 }, { 1536, 0x1A }, { 1792, 0x3E }, { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D }, { 3072, 0x1E }, { 3840, 0x1F } }; if (i2c_bus == NULL) return RTEMS_INVALID_ADDRESS; for (i = 0, mbc = -1; i < sizeof(dividers)/sizeof(dividers[0]); i++) { mbc = dividers[i].mbc; if (dividers[i].divider >= divider) { break; } } *MCF5206E_MFDR(i2c_bus->base) = mbc; return RTEMS_SUCCESSFUL; } /* mcfmbus_initialize -- * Initialize ColdFire MBUS I2C bus controller. * * PARAMETERS: * i2c_bus - pointer to the bus descriptor structure * base - ColdFire internal peripherial base address * * RETURNS: * RTEMS_SUCCESSFUL, or RTEMS error code when initialization failed. */ rtems_status_code mcfmbus_initialize(mcfmbus *i2c_bus, uint32_t base) { rtems_interrupt_level level; rtems_status_code sc; if (mbus != NULL) /* Check if already initialized */ return RTEMS_RESOURCE_IN_USE; if (i2c_bus == NULL) return RTEMS_INVALID_ADDRESS; i2c_bus->base = base; i2c_bus->state = STATE_IDLE; i2c_bus->msg = NULL; i2c_bus->cmsg = NULL; i2c_bus->nmsg = 0; i2c_bus->byte = 0; sc = rtems_interrupt_catch( mcfmbus_interrupt_handler, 24 + ((*MCF5206E_ICR(base, MCF5206E_INTR_MBUS) & MCF5206E_ICR_IL) >> MCF5206E_ICR_IL_S), &i2c_bus->oldisr ); if (sc != RTEMS_SUCCESSFUL) return sc; mbus = i2c_bus; rtems_interrupt_disable(level); *MCF5206E_IMR(base) &= ~MCF5206E_INTR_BIT(MCF5206E_INTR_MBUS); *MCF5206E_MBCR(base) = 0; *MCF5206E_MBSR(base) = 0; *MCF5206E_MBDR(base) = 0x1F; /* Maximum possible divider is 3840 */ *MCF5206E_MBCR(base) = MCF5206E_MBCR_MEN | MCF5206E_MBCR_MIEN; rtems_interrupt_enable(level); return RTEMS_SUCCESSFUL; } /* mcfmbus_i2c_transfer -- * Initiate multiple-messages transfer over I2C bus via ColdFire MBUS * controller. * * PARAMETERS: * bus - pointer to MBUS controller descriptor * nmsg - number of messages * msg - pointer to messages array * done - function which is called when transfer is finished * done_arg_ptr - arbitrary argument ptr passed to done funciton * * RETURNS: * RTEMS_SUCCESSFUL if transfer initiated successfully, or error * code when failed. */ rtems_status_code mcfmbus_i2c_transfer(mcfmbus *bus, int nmsg, i2c_message *msg, i2c_transfer_done done, void *done_arg_ptr) { if (bus != mbus) return RTEMS_NOT_CONFIGURED; bus->done = done; bus->done_arg_ptr = done_arg_ptr; bus->cmsg = bus->msg = msg; bus->nmsg = nmsg; bus->byte = 0; bus->state = STATE_IDLE; mcfmbus_machine(bus, EVENT_TRANSFER); return RTEMS_SUCCESSFUL; } /* mcfmbus_i2c_done -- * Close ColdFire MBUS I2C bus controller and release all resources. * * PARAMETERS: * bus - pointer to MBUS controller descriptor * * RETURNS: * RTEMS_SUCCESSFUL, if transfer initiated successfully, or error * code when failed. */ rtems_status_code mcfmbus_i2c_done(mcfmbus *i2c_bus) { rtems_status_code sc; uint32_t base; if (mbus == NULL) return RTEMS_NOT_CONFIGURED; if (mbus != i2c_bus) return RTEMS_INVALID_ADDRESS; base = i2c_bus->base; *MCF5206E_IMR(base) |= MCF5206E_INTR_BIT(MCF5206E_INTR_MBUS); *MCF5206E_MBCR(base) = 0; sc = rtems_interrupt_catch( i2c_bus->oldisr, 24 + ((*MCF5206E_ICR(base, MCF5206E_INTR_MBUS) & MCF5206E_ICR_IL) >> MCF5206E_ICR_IL_S), NULL ); return sc; }