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Move per-transition delays from generic bit-bashing layer to i2c layer

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(since SPI bit-bashing will require different delay semantics).
This commit is contained in:
Michael Brown
2006-06-14 00:20:35 +00:00
parent 714641ae6d
commit ab4f96e525
3 changed files with 15 additions and 10 deletions
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1
src/drivers/bitbash/bitbash.c
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@@ -38,7 +38,6 @@
void write_bit ( struct bit_basher *basher, unsigned int bit_id, void write_bit ( struct bit_basher *basher, unsigned int bit_id,
unsigned long data ) { unsigned long data ) {
basher->write ( basher, bit_id, ( data ? -1UL : 0 ) ); basher->write ( basher, bit_id, ( data ? -1UL : 0 ) );
udelay ( basher->udelay );
} }
/** /**

22
src/drivers/bitbash/i2c_bit.c
View File

@@ -31,15 +31,25 @@
* that provides two lines: SCL (clock) and SDA (data). * 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 * Set state of I2C SCL line
* *
* @v basher Bit-bashing interface * @v basher Bit-bashing interface
* @v state New state of SCL * @v state New state of SCL
*/ */
static inline __attribute__ (( always_inline )) void static void setscl ( struct bit_basher *basher, int state ) {
setscl ( struct bit_basher *basher, int state ) {
write_bit ( basher, I2C_BIT_SCL, 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 basher Bit-bashing interface
* @v state New state of SDA * @v state New state of SDA
*/ */
static inline __attribute__ (( always_inline )) void static void setsda ( struct bit_basher *basher, int state ) {
setsda ( struct bit_basher *basher, int state ) {
write_bit ( basher, I2C_BIT_SDA, 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 * @v basher Bit-bashing interface
* @ret state State of SDA * @ret state State of SDA
*/ */
static inline __attribute__ (( always_inline )) int static int getsda ( struct bit_basher *basher ) {
getsda ( struct bit_basher *basher ) {
return read_bit ( basher, I2C_BIT_SDA ); 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 ); assert ( basher->write != NULL );
i2cbit->i2c.read = i2c_bit_read; i2cbit->i2c.read = i2c_bit_read;
i2cbit->i2c.write = i2c_bit_write; i2cbit->i2c.write = i2c_bit_write;
basher->udelay = I2C_UDELAY;
i2c_stop ( basher ); i2c_stop ( basher );
} }

2
src/include/gpxe/bitbash.h
View File

@@ -33,8 +33,6 @@ struct bit_basher {
* @ret non-zero Input is a logic 1 * @ret non-zero Input is a logic 1
*/ */
int ( * read ) ( struct bit_basher *basher, unsigned int bit_id ); 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, extern void write_bit ( struct bit_basher *basher, unsigned int bit_id,