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: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/spi/spi_butterfly.c b/drivers/spi/spi_butterfly.c
index 574d0fae4c590e3388913000d535633d181d3280..0ee2b2090252999f7df59f8704ff5e2bcea2ce9a 100644 (file)
--- a/drivers/spi/spi_butterfly.c
+++ b/drivers/spi/spi_butterfly.c
@@ -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 */
@@ -97,23 +80,13 @@ 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;
+       bit = spi_sck_bit;
 
        if (is_on)
                byte |= bit;
@@ -129,10 +102,7 @@ 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;
+       bit = spi_mosi_bit;
 
        if (is_on)
                byte |= bit;
@@ -148,10 +118,7 @@ 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;
+       bit = spi_miso_bit;
 
        /* only STATUS_BUSY is NOT negated */
        value = !(parport_read_status(pp->port) & bit);
@@ -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;