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Commit 41c4221c authored by hartleys's avatar hartleys Committed by Grant Likely
Browse files

spi: move bitbang txrx utility functions to private header 



A number of files in drivers/spi fail checkincludes.pl due to the double
include of <linux/spi/spi_bitbang.h>.

The first include is needed to get the struct spi_bitbang definition and
the spi_bitbang_* function prototypes.

The second include happens after defining EXPAND_BITBANG_TXRX to get the
inlined bitbang_txrx_* utility functions.

The <linux/spi/spi_bitbang.h> header is also included by a number of other
spi drivers, as well as some arch/ code, in order to use struct spi_bitbang
and the associated functions.

To fix the double include, and remove any potential confusion about it, move
the inlined bitbang_txrx_* functions to a new private header in drivers/spi
and also remove the need to define EXPAND_BITBANG_TXRX.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 6e27388f

drivers/spi/spi_bitbang_txrx.h

0 → 100644
+93 −0
Original line number Diff line number Diff line 
/*

 * Mix this utility code with some glue code to get one of several types of

 * simple SPI master driver.  Two do polled word-at-a-time I/O:

 *

 *   -	GPIO/parport bitbangers.  Provide chipselect() and txrx_word[](),

 *	expanding the per-word routines from the inline templates below.

 *

 *   -	Drivers for controllers resembling bare shift registers.  Provide

 *	chipselect() and txrx_word[](), with custom setup()/cleanup() methods

 *	that use your controller's clock and chipselect registers.

 *

 * Some hardware works well with requests at spi_transfer scope:

 *

 *   -	Drivers leveraging smarter hardware, with fifos or DMA; or for half

 *	duplex (MicroWire) controllers.  Provide chipselect() and txrx_bufs(),

 *	and custom setup()/cleanup() methods.

 */



/*

 * The code that knows what GPIO pins do what should have declared four

 * functions, ideally as inlines, before including this header:

 *

 *  void setsck(struct spi_device *, int is_on);

 *  void setmosi(struct spi_device *, int is_on);

 *  int getmiso(struct spi_device *);

 *  void spidelay(unsigned);

 *

 * setsck()'s is_on parameter is a zero/nonzero boolean.

 *

 * setmosi()'s is_on parameter is a zero/nonzero boolean.

 *

 * getmiso() is required to return 0 or 1 only. Any other value is invalid

 * and will result in improper operation.

 *

 * A non-inlined routine would call bitbang_txrx_*() routines.  The

 * main loop could easily compile down to a handful of instructions,

 * especially if the delay is a NOP (to run at peak speed).

 *

 * Since this is software, the timings may not be exactly what your board's

 * chips need ... there may be several reasons you'd need to tweak timings

 * in these routines, not just make to make it faster or slower to match a

 * particular CPU clock rate.

 */



static inline u32

bitbang_txrx_be_cpha0(struct spi_device *spi,

		unsigned nsecs, unsigned cpol,

		u32 word, u8 bits)

{

	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */



	/* clock starts at inactive polarity */

	for (word <<= (32 - bits); likely(bits); bits--) {



		/* setup MSB (to slave) on trailing edge */

		setmosi(spi, word & (1 << 31));

		spidelay(nsecs);	/* T(setup) */



		setsck(spi, !cpol);

		spidelay(nsecs);



		/* sample MSB (from slave) on leading edge */

		word <<= 1;

		word |= getmiso(spi);

		setsck(spi, cpol);

	}

	return word;

}



static inline u32

bitbang_txrx_be_cpha1(struct spi_device *spi,

		unsigned nsecs, unsigned cpol,

		u32 word, u8 bits)

{

	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */



	/* clock starts at inactive polarity */

	for (word <<= (32 - bits); likely(bits); bits--) {



		/* setup MSB (to slave) on leading edge */

		setsck(spi, !cpol);

		setmosi(spi, word & (1 << 31));

		spidelay(nsecs); /* T(setup) */



		setsck(spi, cpol);

		spidelay(nsecs);



		/* sample MSB (from slave) on trailing edge */

		word <<= 1;

		word |= getmiso(spi);

	}

	return word;

}

drivers/spi/spi_butterfly.c

+1 −2
Original line number Diff line number Diff line
@@ -149,8 +149,7 @@ static void butterfly_chipselect(struct spi_device *spi, int value) 
#define	spidelay(X)	do{}while(0)

//#define	spidelay	ndelay



#define	EXPAND_BITBANG_TXRX

#include <linux/spi/spi_bitbang.h>

#include "spi_bitbang_txrx.h"



static u32

butterfly_txrx_word_mode0(struct spi_device *spi,

drivers/spi/spi_gpio.c

+1 −2
Original line number Diff line number Diff line
@@ -127,8 +127,7 @@ static inline int getmiso(const struct spi_device *spi) 
 */

#define spidelay(nsecs)	do {} while (0)



#define	EXPAND_BITBANG_TXRX

#include <linux/spi/spi_bitbang.h>

#include "spi_bitbang_txrx.h"



/*

 * These functions can leverage inline expansion of GPIO calls to shrink

drivers/spi/spi_lm70llp.c

+1 −2
Original line number Diff line number Diff line
@@ -174,8 +174,7 @@ static inline int getmiso(struct spi_device *s) 
}

/*--------------------------------------------------------------------*/



#define EXPAND_BITBANG_TXRX 1

#include <linux/spi/spi_bitbang.h>

#include "spi_bitbang_txrx.h"



static void lm70_chipselect(struct spi_device *spi, int value)

{

drivers/spi/spi_s3c24xx_gpio.c

+1 −2
Original line number Diff line number Diff line
@@ -58,8 +58,7 @@ static inline u32 getmiso(struct spi_device *dev) 


#define spidelay(x) ndelay(x)



#define	EXPAND_BITBANG_TXRX

#include <linux/spi/spi_bitbang.h>

#include "spi_bitbang_txrx.h"





static u32 s3c2410_spigpio_txrx_mode0(struct spi_device *spi,