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Commit 735ce95e authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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minor spi_butterfly cleanup 



Simplify the spi_butterfly driver by removing incomplete/unused support for
the second SPI bus, implemented by the USI controller.  This should make
this a clearer example of how to write a parport bitbang driver.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fef92c30

drivers/spi/spi_butterfly.c

+4 −58
Original line number Diff line number Diff line
@@ -40,8 +40,6 @@ 
 * and use this custom parallel port cable.

 */



#undef	HAVE_USI	/* nyet */





/* DATA output bits (pins 2..9 == D0..D7) */

#define	butterfly_nreset (1 << 1)		/* pin 3 */
@@ -49,19 +47,13 @@ 
#define	spi_sck_bit	(1 << 0)		/* pin 2 */

#define	spi_mosi_bit	(1 << 7)		/* pin 9 */



#define	usi_sck_bit	(1 << 3)		/* pin 5 */

#define	usi_mosi_bit	(1 << 4)		/* pin 6 */



#define	vcc_bits	((1 << 6) | (1 << 5))	/* pins 7, 8 */



/* STATUS input bits */

#define	spi_miso_bit	PARPORT_STATUS_BUSY	/* pin 11 */



#define	usi_miso_bit	PARPORT_STATUS_PAPEROUT	/* pin 12 */



/* CONTROL output bits */

#define	spi_cs_bit	PARPORT_CONTROL_SELECT	/* pin 17 */

/* USI uses no chipselect */
@@ -70,15 +62,6 @@ static inline struct butterfly *spidev_to_pp(struct spi_device *spi) 
	return spi->controller_data;

}



static inline int is_usidev(struct spi_device *spi)

{

#ifdef	HAVE_USI

	return spi->chip_select != 1;

#else

	return 0;

#endif

}





struct butterfly {

	/* REVISIT ... for now, this must be first */
@@ -97,22 +80,12 @@ struct butterfly { 


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



/*

 * these routines may be slower than necessary because they're hiding

 * the fact that there are two different SPI busses on this cable: one

 * to the DataFlash chip (or AVR SPI controller), the other to the

 * AVR USI controller.

 */



static inline void

setsck(struct spi_device *spi, int is_on)

{

	struct butterfly	*pp = spidev_to_pp(spi);

	u8			bit, byte = pp->lastbyte;



	if (is_usidev(spi))

		bit = usi_sck_bit;

	else

	bit = spi_sck_bit;



	if (is_on)
@@ -129,9 +102,6 @@ setmosi(struct spi_device *spi, int is_on) 
	struct butterfly	*pp = spidev_to_pp(spi);

	u8			bit, byte = pp->lastbyte;



	if (is_usidev(spi))

		bit = usi_mosi_bit;

	else

	bit = spi_mosi_bit;



	if (is_on)
@@ -148,9 +118,6 @@ static inline int getmiso(struct spi_device *spi) 
	int			value;

	u8			bit;



	if (is_usidev(spi))

		bit = usi_miso_bit;

	else

	bit = spi_miso_bit;



	/* only STATUS_BUSY is NOT negated */
@@ -166,10 +133,6 @@ static void butterfly_chipselect(struct spi_device *spi, int value) 
	if (value != BITBANG_CS_INACTIVE)

		setsck(spi, spi->mode & SPI_CPOL);



	/* no chipselect on this USI link config */

	if (is_usidev(spi))

		return;



	/* here, value == "activate or not";

	 * most PARPORT_CONTROL_* bits are negated, so we must

	 * morph it to value == "bit value to write in control register"
@@ -292,7 +255,7 @@ static void butterfly_attach(struct parport *p) 
	parport_frob_control(pp->port, spi_cs_bit, 0);



	/* stabilize power with chip in reset (nRESET), and

	 * both spi_sck_bit and usi_sck_bit clear (CPOL=0)

	 * spi_sck_bit clear (CPOL=0)

	 */

	pp->lastbyte |= vcc_bits;

	parport_write_data(pp->port, pp->lastbyte);
@@ -326,23 +289,6 @@ static void butterfly_attach(struct parport *p) 
		pr_debug("%s: dataflash at %s\n", p->name,

				pp->dataflash->dev.bus_id);



#ifdef	HAVE_USI

	/* Bus 2 is only for talking to the AVR, and it can work no

	 * matter who masters bus 1; needs appropriate AVR firmware.

	 */

	pp->info[1].max_speed_hz = 10 /* ?? */ * 1000 * 1000;

	strcpy(pp->info[1].modalias, "butterfly");

	// pp->info[1].platform_data = ... TBD ... ;

	pp->info[1].chip_select = 2,

	pp->info[1].controller_data = pp;

	pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[1]);

	if (pp->butterfly)

		pr_debug("%s: butterfly at %s\n", p->name,

				pp->butterfly->dev.bus_id);



	/* FIXME setup ACK for the IRQ line ...  */

#endif



	// dev_info(_what?_, ...)

	pr_info("%s: AVR Butterfly\n", p->name);

	butterfly = pp;