From ab4f96e525fe082b0750867cc50d03becf018048 Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@etherboot.org>
Date: Wed, 14 Jun 2006 00:20:35 +0000
Subject: [PATCH] Move per-transition delays from generic bit-bashing layer to
 i2c layer (since SPI bit-bashing will require different delay semantics).

---
 src/drivers/bitbash/bitbash.c |  1 -
 src/drivers/bitbash/i2c_bit.c | 22 +++++++++++++++-------
 src/include/gpxe/bitbash.h    |  2 --
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/drivers/bitbash/bitbash.c b/src/drivers/bitbash/bitbash.c
index 92abe1a7..19add4ce 100644
--- a/src/drivers/bitbash/bitbash.c
+++ b/src/drivers/bitbash/bitbash.c
@@ -38,7 +38,6 @@
 void write_bit ( struct bit_basher *basher, unsigned int bit_id,
 		 unsigned long data ) {
 	basher->write ( basher, bit_id, ( data ? -1UL : 0 ) );
-	udelay ( basher->udelay );
 }
 
 /**
diff --git a/src/drivers/bitbash/i2c_bit.c b/src/drivers/bitbash/i2c_bit.c
index cc73968b..2551bb4f 100644
--- a/src/drivers/bitbash/i2c_bit.c
+++ b/src/drivers/bitbash/i2c_bit.c
@@ -31,15 +31,25 @@
  * that provides two lines: SCL (clock) and SDA (data).
  */
 
+/**
+ * Delay between output state changes
+ *
+ * Max rated i2c speed (for the basic i2c protocol) is 100kbps,
+ * i.e. 200k clock transitions per second.
+ */
+static void i2c_delay ( void ) {
+	udelay ( I2C_UDELAY );
+}
+
 /**
  * Set state of I2C SCL line
  *
  * @v basher		Bit-bashing interface
  * @v state		New state of SCL
  */
-static inline __attribute__ (( always_inline )) void
-setscl ( struct bit_basher *basher, int state ) {
+static void setscl ( struct bit_basher *basher, int state ) {
 	write_bit ( basher, I2C_BIT_SCL, state );
+	i2c_delay();
 }
 
 /**
@@ -48,9 +58,9 @@ setscl ( struct bit_basher *basher, int state ) {
  * @v basher		Bit-bashing interface
  * @v state		New state of SDA
  */
-static inline __attribute__ (( always_inline )) void
-setsda ( struct bit_basher *basher, int state ) {
+static void setsda ( struct bit_basher *basher, int state ) {
 	write_bit ( basher, I2C_BIT_SDA, state );
+	i2c_delay();
 }
 
 /**
@@ -59,8 +69,7 @@ setsda ( struct bit_basher *basher, int state ) {
  * @v basher		Bit-bashing interface
  * @ret state		State of SDA
  */
-static inline __attribute__ (( always_inline )) int
-getsda ( struct bit_basher *basher ) {
+static int getsda ( struct bit_basher *basher ) {
 	return read_bit ( basher, I2C_BIT_SDA );
 }
 
@@ -308,6 +317,5 @@ void init_i2c_bit_basher ( struct i2c_bit_basher *i2cbit ) {
 	assert ( basher->write != NULL );
 	i2cbit->i2c.read = i2c_bit_read;
 	i2cbit->i2c.write = i2c_bit_write;
-	basher->udelay = I2C_UDELAY;
 	i2c_stop ( basher );
 }
diff --git a/src/include/gpxe/bitbash.h b/src/include/gpxe/bitbash.h
index 9bee3913..f479b5ad 100644
--- a/src/include/gpxe/bitbash.h
+++ b/src/include/gpxe/bitbash.h
@@ -33,8 +33,6 @@ struct bit_basher {
 	 * @ret non-zero	Input is a logic 1
 	 */
 	int ( * read ) ( struct bit_basher *basher, unsigned int bit_id );
-	/** Delay between subsequent calls to write(), in microseconds */
-	unsigned int udelay;
 };
 
 extern void write_bit ( struct bit_basher *basher, unsigned int bit_id,