patch-2.4.25 linux-2.4.25/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c

• Lines: 172
• Date: 2004-02-18 05:36:30.000000000 -0800
• Orig file: linux-2.4.24/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c linux-2.4.25/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();
+}