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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c
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Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c')
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diff --git a/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c b/arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c
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+++ 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();
+}