+++ /dev/null
-/*
- * spi_butterfly.c - parport-to-butterfly adapter
- *
- * Copyright (C) 2005 David Brownell
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/delay.h>
-#include <linux/device.h>
-#include <linux/parport.h>
-
-#include <linux/sched.h>
-#include <linux/spi/spi.h>
-#include <linux/spi/spi_bitbang.h>
-
-
-
-/*
- * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
- * with a battery powered AVR microcontroller and lots of goodies. You
- * can use GCC to develop firmware for this.
- *
- * See Documentation/spi/butterfly for information about how to build
- * and use this custom parallel port cable.
- */
-
-/*
- * spi_device
- * todo:
- * - implement SPI mode 1,2,3 is yet missing
- * - prevent ugly handling of global butterfly structure
- * - use serial subsystem
- * - make stuff module configurable during runtime
- */
-
-/* DATA output bits (pins 2..9 == D0..D7) */
-#define butterfly_nreset (1 << 1) /* pin 3 */
-
-#define spi_sck_bit (1 << 0) /* pin 2 */
-#define spi_mosi_bit (1 << 7) /* pin 9 */
-
-#define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */
-
-/* STATUS input bits */
-#define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */
-
-/* CONTROL output bits */
-#define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
-
-
-
-static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
-{
- return spi->controller_data;
-}
-
-
-struct butterfly {
- /* REVISIT ... for now, this must be first */
- struct spi_bitbang bitbang;
-
- struct parport *port;
- struct pardevice *pd;
-
- u8 lastbyte;
-
- struct spi_message *msg;
- struct spi_device *butterfly;
- struct spi_board_info info[2];
-
-};
-
-/*----------------------------------------------------------------------*/
-
-static inline void
-setsck(struct spi_device *spi, int is_on)
-{
- struct butterfly *pp = spidev_to_pp(spi);
- u8 bit, byte = pp->lastbyte;
-
- bit = spi_sck_bit;
-
- if (is_on)
- byte |= bit;
- else
- byte &= ~bit;
- parport_write_data(pp->port, byte);
- pp->lastbyte = byte;
-}
-
-static inline void
-setmosi(struct spi_device *spi, int is_on)
-{
- struct butterfly *pp = spidev_to_pp(spi);
- u8 bit, byte = pp->lastbyte;
-
- bit = spi_mosi_bit;
-
- if (is_on)
- byte |= bit;
- else
- byte &= ~bit;
- parport_write_data(pp->port, byte);
- pp->lastbyte = byte;
-}
-
-static inline int getmiso(struct spi_device *spi)
-{
- struct butterfly *pp = spidev_to_pp(spi);
- int value;
- u8 bit;
-
- bit = spi_miso_bit;
-
- /* only STATUS_BUSY is NOT negated */
- value = !(parport_read_status(pp->port) & bit);
- return (bit == PARPORT_STATUS_BUSY) ? value : !value;
-}
-
-static void butterfly_chipselect(struct spi_device *spi, int value)
-{
- struct butterfly *pp = spidev_to_pp(spi);
-
- /* set default clock polarity */
- if (value != BITBANG_CS_INACTIVE)
- setsck(spi, spi->mode & SPI_CPOL);
-
- /* 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"
- */
- if (spi_cs_bit == PARPORT_CONTROL_INIT)
- value = !value;
-
- parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
-}
-
-
-/* we only needed to implement one mode here, and choose SPI_MODE_0 */
-
-#define spidelay(X) do{}while(0)
-//#define spidelay ndelay
-
-#define EXPAND_BITBANG_TXRX
-#include <linux/spi/spi_bitbang.h>
-
-static u32
-butterfly_txrx_word_mode0(struct spi_device *spi,
- unsigned nsecs,
- u32 word, u8 bits)
-{
- return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
-}
-
-/*----------------------------------------------------------------------*/
-
-/* REVISIT remove this ugly global and its "only one" limitation */
-static struct butterfly *butterfly;
-
-static void butterfly_attach(struct parport *p)
-{
- struct pardevice *pd;
- int status;
- struct butterfly *pp;
- struct spi_master *master;
- struct device *dev = p->physport->dev;
-
- if (butterfly || !dev)
- return;
-
- /* REVISIT: this just _assumes_ a butterfly is there ... no probe,
- * and no way to be selective about what it binds to.
- */
-
- master = spi_alloc_master(dev, sizeof *pp);
- if (!master) {
- status = -ENOMEM;
- goto done;
- }
- pp = spi_master_get_devdata(master);
-
- /*
- * SPI and bitbang hookup
- *
- * use default setup(), cleanup(), and transfer() methods; and
- * only bother implementing mode 0. Start it later.
- */
- master->bus_num = 42; // hard coded?!?
- master->num_chipselect = 2; // hard coded?!?
-
- pp->bitbang.master = spi_master_get(master);
- pp->bitbang.chipselect = butterfly_chipselect;
- pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;
-
- /*
- * parport hookup
- */
- pp->port = p;
- pd = parport_register_device(p, "spi_butterfly",
- NULL, NULL, NULL,
- 0 /* FLAGS */, pp);
- if (!pd) {
- status = -ENOMEM;
- goto clean0;
- }
- pp->pd = pd;
-
- status = parport_claim(pd);
- if (status < 0)
- goto clean1;
-
- /*
- * Butterfly reset, powerup, run firmware
- */
- pr_debug("%s: powerup/reset Butterfly\n", p->name);
-
- /* nCS for dataflash (this bit is inverted on output) */
- parport_frob_control(pp->port, spi_cs_bit, 0);
-
- /* stabilize power with chip in reset (nRESET), and
- * spi_sck_bit clear (CPOL=0)
- */
- pp->lastbyte |= vcc_bits;
- parport_write_data(pp->port, pp->lastbyte);
- msleep(5);
-
- /* take it out of reset; assume long reset delay */
- pp->lastbyte |= butterfly_nreset;
- parport_write_data(pp->port, pp->lastbyte);
- msleep(100);
-
-
- /*
- * Start SPI ... for now, hide that we're two physical busses.
- */
- status = spi_bitbang_start(&pp->bitbang);
- if (status < 0)
- goto clean2;
-
- /* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR
- * (firmware resets at45, acts as spi slave) or neither (we ignore
- * both, AVR uses AT45). Here we expect firmware for the first option.
- */
-
- pp->info[0].max_speed_hz = 15 * 1000 * 1000;
-
- strcpy(pp->info[0].modalias, "spi_tty"); // name length check ! < KOBJ_NAME_LEN
- pp->info[0].platform_data = NULL; // here we should add data structures for subsystem driver ???
- pp->info[0].chip_select = 1; // 0: .. 1:
- pp->info[0].controller_data = pp; /* save my structure for later use */
- pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[0]);
- if (pp->butterfly)
- pr_debug("%s: dataflash at %s\n", p->name,
- pp->butterfly->dev.bus_id);
-
- // dev_info(_what?_, ...)
- pr_info("%s: AVR Butterfly\n", p->name);
-
-
- /* get spi_bitbang_transfer either via global Symbol, or better
- * ask it from the driver structure
- */
- pp->msg = spi_message_alloc(1, GFP_KERNEL);
- if (master) { /* the same address is also saved in pp->bitbang.master or pp->butterfly->master */
- struct spi_message *spi_msg;
- spi_msg = pp->msg;
- if (spi_msg) {
- // spi_message_init(spi_msg);
- pr_info("Alloc SPI message buffer\n");
- spi_msg->spi = pp->butterfly;
- spi_msg->actual_length = 1;
-#if 0
- spi_msg->list_head ... Addresse der ersten SPI transfer struct
-
-
- spi_msg->tx_buf = ;
- spi_msg->len = 1;
- spi_msg->cs_change = 1;
- spi_msg->delay_usecs = 0;
-
- /* fill up message */
- master->transfer(pp->butterfly, spi_msg);
-#endif
- }
- }
- butterfly = pp;
- return;
-
-clean2:
- /* turn off VCC */
- parport_write_data(pp->port, 0);
-
- parport_release(pp->pd);
-clean1:
- parport_unregister_device(pd);
-clean0:
- (void) spi_master_put(pp->bitbang.master);
-done:
- pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
-}
-
-static void butterfly_detach(struct parport *p)
-{
- struct butterfly *pp;
- int status;
-
- /* FIXME this global is ugly ... but, how to quickly get from
- * the parport to the "struct butterfly" associated with it?
- * "old school" driver-internal device lists?
- */
- if (!butterfly || butterfly->port != p)
- return;
- pp = butterfly;
- if (pp->msg) {
- spi_message_free(pp->msg);
- pr_info("Dealloc SPI message buffer\n");
- }
- butterfly = NULL;
-
- /* stop() unregisters child devices too */
- status = spi_bitbang_stop(&pp->bitbang);
-
- /* turn off VCC */
- parport_write_data(pp->port, 0);
- msleep(10);
-
- parport_release(pp->pd);
- parport_unregister_device(pp->pd);
-
- (void) spi_master_put(pp->bitbang.master);
-}
-
-static struct parport_driver butterfly_driver = {
- .name = "spi_butterfly",
- .attach = butterfly_attach,
- .detach = butterfly_detach,
-};
-
-
-static int __init butterfly_init(void)
-{
- return parport_register_driver(&butterfly_driver);
-}
-device_initcall(butterfly_init);
-
-static void __exit butterfly_exit(void)
-{
- parport_unregister_driver(&butterfly_driver);
-}
-module_exit(butterfly_exit);
-
-MODULE_DESCRIPTION("Parport Adapter driver for SPI tty Butterfly");
-MODULE_LICENSE("GPL");
projects / pub / spi-gpio-pp.git / blobdiff