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>
This commit is contained in:
David Brownell
Linus Torvalds
Родитель
fef92c30d4
Коммит
735ce95e6b
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@ -40,8 +40,6 @@
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* and use this custom parallel port cable.
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*/
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#undef HAVE_USI /* nyet */
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/* DATA output bits (pins 2..9 == D0..D7) */
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#define butterfly_nreset (1 << 1) /* pin 3 */
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@ -49,19 +47,13 @@
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#define spi_sck_bit (1 << 0) /* pin 2 */
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#define spi_mosi_bit (1 << 7) /* pin 9 */
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#define usi_sck_bit (1 << 3) /* pin 5 */
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#define usi_mosi_bit (1 << 4) /* pin 6 */
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#define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */
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/* STATUS input bits */
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#define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */
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#define usi_miso_bit PARPORT_STATUS_PAPEROUT /* pin 12 */
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/* CONTROL output bits */
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#define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
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/* USI uses no chipselect */
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@ -70,15 +62,6 @@ static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
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return spi->controller_data;
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}
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static inline int is_usidev(struct spi_device *spi)
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{
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#ifdef HAVE_USI
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return spi->chip_select != 1;
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#else
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return 0;
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#endif
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}
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struct butterfly {
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/* REVISIT ... for now, this must be first */
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@ -97,23 +80,13 @@ struct butterfly {
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/*----------------------------------------------------------------------*/
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/*
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* these routines may be slower than necessary because they're hiding
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* the fact that there are two different SPI busses on this cable: one
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* to the DataFlash chip (or AVR SPI controller), the other to the
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* AVR USI controller.
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*/
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static inline void
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setsck(struct spi_device *spi, int is_on)
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{
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struct butterfly *pp = spidev_to_pp(spi);
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u8 bit, byte = pp->lastbyte;
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if (is_usidev(spi))
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bit = usi_sck_bit;
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else
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bit = spi_sck_bit;
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bit = spi_sck_bit;
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if (is_on)
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byte |= bit;
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@ -129,10 +102,7 @@ setmosi(struct spi_device *spi, int is_on)
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struct butterfly *pp = spidev_to_pp(spi);
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u8 bit, byte = pp->lastbyte;
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if (is_usidev(spi))
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bit = usi_mosi_bit;
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else
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bit = spi_mosi_bit;
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bit = spi_mosi_bit;
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if (is_on)
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byte |= bit;
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@ -148,10 +118,7 @@ static inline int getmiso(struct spi_device *spi)
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int value;
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u8 bit;
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if (is_usidev(spi))
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bit = usi_miso_bit;
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else
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bit = spi_miso_bit;
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bit = spi_miso_bit;
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/* only STATUS_BUSY is NOT negated */
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value = !(parport_read_status(pp->port) & bit);
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@ -166,10 +133,6 @@ static void butterfly_chipselect(struct spi_device *spi, int value)
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if (value != BITBANG_CS_INACTIVE)
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setsck(spi, spi->mode & SPI_CPOL);
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/* no chipselect on this USI link config */
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if (is_usidev(spi))
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return;
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/* here, value == "activate or not";
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* most PARPORT_CONTROL_* bits are negated, so we must
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* morph it to value == "bit value to write in control register"
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@ -292,7 +255,7 @@ static void butterfly_attach(struct parport *p)
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parport_frob_control(pp->port, spi_cs_bit, 0);
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/* stabilize power with chip in reset (nRESET), and
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* both spi_sck_bit and usi_sck_bit clear (CPOL=0)
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* spi_sck_bit clear (CPOL=0)
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*/
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pp->lastbyte |= vcc_bits;
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parport_write_data(pp->port, pp->lastbyte);
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@ -326,23 +289,6 @@ static void butterfly_attach(struct parport *p)
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pr_debug("%s: dataflash at %s\n", p->name,
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pp->dataflash->dev.bus_id);
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#ifdef HAVE_USI
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/* Bus 2 is only for talking to the AVR, and it can work no
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* matter who masters bus 1; needs appropriate AVR firmware.
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*/
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pp->info[1].max_speed_hz = 10 /* ?? */ * 1000 * 1000;
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strcpy(pp->info[1].modalias, "butterfly");
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// pp->info[1].platform_data = ... TBD ... ;
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pp->info[1].chip_select = 2,
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pp->info[1].controller_data = pp;
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pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[1]);
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if (pp->butterfly)
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pr_debug("%s: butterfly at %s\n", p->name,
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pp->butterfly->dev.bus_id);
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/* FIXME setup ACK for the IRQ line ... */
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#endif
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// dev_info(_what?_, ...)
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pr_info("%s: AVR Butterfly\n", p->name);
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butterfly = pp;
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