diff options
Diffstat (limited to 'arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c')
| -rw-r--r-- | arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c b/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c new file mode 100644 index 00000000000..b067988614c --- /dev/null +++ b/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c @@ -0,0 +1,171 @@ +/* + * arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c + * + * Copyright (C) 2003 PMC-Sierra Inc. + * Author: Manish Lachwani (lachwani@pmc-sierra.com) + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/* + * Description: + * + * This code reads the ATMEL 24CXX EEPROM. The PMC-Sierra Yosemite board uses the ATMEL + * 24C32/24C64 which uses two byte addressing as compared to 24C16. Note that this program + * uses the serial port like /dev/ttyS0, to communicate with the EEPROM. Hence, you are + * expected to have a connectivity from the EEPROM to the serial port. This program does + * __not__ communicate using the I2C protocol + */ + +#include "atmel_read_eeprom.h" + +static void delay(int delay) +{ + while (delay--); +} + +static void send_bit(unsigned char bit) +{ + scl_lo; + delay(TXX); + if (bit) + sda_hi; + else + sda_lo; + + delay(TXX); + scl_hi; + delay(TXX); +} + +static void send_ack(void) +{ + send_bit(0); +} + +static void send_byte(unsigned char byte) +{ + int i = 0; + + for (i = 7; i >= 0; i--) + send_bit((byte >> i) & 0x01); +} + +static void send_start(void) +{ + sda_hi; + delay(TXX); + scl_hi; + delay(TXX); + sda_lo; + delay(TXX); +} + +static void send_stop(void) +{ + sda_lo; + delay(TXX); + scl_hi; + delay(TXX); + sda_hi; + delay(TXX); +} + +static void do_idle(void) +{ + sda_hi; + scl_hi; + vcc_off; +} + +static int recv_bit(void) +{ + int status; + + scl_lo; + delay(TXX); + sda_hi; + delay(TXX); + scl_hi; + delay(TXX); + + return 1; +} + +static unsigned char recv_byte(void) { + int i; + unsigned char byte=0; + + for (i=7;i>=0;i--) + byte |= (recv_bit() << i); + + return byte; +} + +static int recv_ack(void) +{ + unsigned int ack; + + ack = (unsigned int)recv_bit(); + scl_lo; + + if (ack) { + do_idle(); + printk(KERN_ERR "Error reading the Atmel 24C32/24C64 EEPROM \n"); + return -1; + } + + return ack; +} + +/* + * This function does the actual read of the EEPROM. It needs the buffer into which the + * read data is copied, the size of the EEPROM being read and the buffer size + */ +int read_eeprom(char *buffer, int eeprom_size, int size) +{ + int i = 0, err; + + send_start(); + send_byte(W_HEADER); + recv_ack(); + + /* EEPROM with size of more then 2K need two byte addressing */ + if (eeprom_size > 2048) { + send_byte(0x00); + recv_ack(); + } + + send_start(); + send_byte(R_HEADER); + err = recv_ack(); + if (err == -1) + return err; + + for (i = 0; i < size; i++) { + *buffer++ = recv_byte(); + send_ack(); + } + + /* Note : We should do some check if the buffer contains correct information */ + + send_stop(); +} |