From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@ppc970.osdl.org>
Date: Sat, 16 Apr 2005 15:20:36 -0700
Subject: Linux-2.6.12-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!
---
 arch/mips/lasat/at93c.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 arch/mips/lasat/at93c.c

(limited to 'arch/mips/lasat/at93c.c')

diff --git a/arch/mips/lasat/at93c.c b/arch/mips/lasat/at93c.c
new file mode 100644
index 00000000000..f6add041ebe
--- /dev/null
+++ b/arch/mips/lasat/at93c.c
@@ -0,0 +1,148 @@
+/* 
+ * Atmel AT93C46 serial eeprom driver
+ *
+ * Brian Murphy <brian.murphy@eicon.com> 
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <asm/lasat/lasat.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include "at93c.h"
+
+#define AT93C_ADDR_SHIFT	7
+#define AT93C_ADDR_MAX		((1 << AT93C_ADDR_SHIFT) - 1)
+#define AT93C_RCMD		(0x6 << AT93C_ADDR_SHIFT)
+#define AT93C_WCMD		(0x5 << AT93C_ADDR_SHIFT)
+#define AT93C_WENCMD		0x260
+#define AT93C_WDSCMD		0x200
+
+struct at93c_defs *at93c;
+
+static void at93c_reg_write(u32 val) 
+{
+	*at93c->reg = val;
+}
+
+static u32 at93c_reg_read(void) 
+{
+	u32 tmp = *at93c->reg;
+	return tmp;
+}
+
+static u32 at93c_datareg_read(void)
+{
+	u32 tmp = *at93c->rdata_reg;
+	return tmp;
+}
+
+static void at93c_cycle_clk(u32 data)
+{
+	at93c_reg_write(data | at93c->clk);
+	lasat_ndelay(250);
+	at93c_reg_write(data & ~at93c->clk);
+	lasat_ndelay(250);
+}
+
+static void at93c_write_databit(u8 bit)
+{
+	u32 data = at93c_reg_read();
+	if (bit)
+		data |= 1 << at93c->wdata_shift;
+	else
+		data &= ~(1 << at93c->wdata_shift);
+
+	at93c_reg_write(data);
+	lasat_ndelay(100);
+	at93c_cycle_clk(data);
+}
+
+static unsigned int at93c_read_databit(void)
+{
+	u32 data;
+
+	at93c_cycle_clk(at93c_reg_read());
+	data = (at93c_datareg_read() >> at93c->rdata_shift) & 1;
+	return data;
+}
+
+static u8 at93c_read_byte(void)
+{
+	int i;
+	u8 data = 0;
+
+	for (i = 0; i<=7; i++) {
+		data <<= 1;
+		data |= at93c_read_databit();
+	}
+	return data;
+}
+
+static void at93c_write_bits(u32 data, int size)
+{               
+	int i;
+	int shift = size - 1;
+	u32 mask = (1 << shift);
+
+	for (i = 0; i < size; i++) {
+		at93c_write_databit((data & mask) >> shift);
+		data <<= 1;
+	}
+}       
+
+static void at93c_init_op(void)
+{
+	at93c_reg_write((at93c_reg_read() | at93c->cs) & ~at93c->clk & ~(1 << at93c->rdata_shift));
+	lasat_ndelay(50);
+}
+
+static void at93c_end_op(void)
+{
+	at93c_reg_write(at93c_reg_read() & ~at93c->cs);
+	lasat_ndelay(250);
+}
+
+static void at93c_wait(void) 
+{ 
+	at93c_init_op();
+	while (!at93c_read_databit())
+		;
+	at93c_end_op();
+};
+
+static void at93c_disable_wp(void)
+{
+	at93c_init_op();
+	at93c_write_bits(AT93C_WENCMD, 10);
+	at93c_end_op();
+}
+
+static void at93c_enable_wp(void)
+{
+	at93c_init_op();
+	at93c_write_bits(AT93C_WDSCMD, 10);
+	at93c_end_op();
+}
+
+u8 at93c_read(u8 addr)
+{
+	u8 byte;
+	at93c_init_op();
+	at93c_write_bits((addr & AT93C_ADDR_MAX)|AT93C_RCMD, 10);
+	byte = at93c_read_byte();
+	at93c_end_op();
+	return byte;
+}
+
+void at93c_write(u8 addr, u8 data)
+{
+	at93c_disable_wp();
+	at93c_init_op();
+	at93c_write_bits((addr & AT93C_ADDR_MAX)|AT93C_WCMD, 10);
+	at93c_write_bits(data, 8);
+	at93c_end_op();
+	at93c_wait();
+	at93c_enable_wp();
+}
-- 
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