mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Axel Lin](/assets/img/avatar_default.png)
spi_bitbang_stop() never fails, so make it return void. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Mark Brown <broonie@linaro.org>
355 lines
8.4 KiB
C
355 lines
8.4 KiB
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/module.h>
|
|
#include <linux/device.h>
|
|
#include <linux/parport.h>
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/spi/spi.h>
|
|
#include <linux/spi/spi_bitbang.h>
|
|
#include <linux/spi/flash.h>
|
|
|
|
#include <linux/mtd/partitions.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.
|
|
*/
|
|
|
|
|
|
/* 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_device *dataflash;
|
|
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 */
|
|
|
|
#include "spi-bitbang-txrx.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, 0, word, bits);
|
|
}
|
|
|
|
/*----------------------------------------------------------------------*/
|
|
|
|
/* override default partitioning with cmdlinepart */
|
|
static struct mtd_partition partitions[] = { {
|
|
/* JFFS2 wants partitions of 4*N blocks for this device,
|
|
* so sectors 0 and 1 can't be partitions by themselves.
|
|
*/
|
|
|
|
/* sector 0 = 8 pages * 264 bytes/page (1 block)
|
|
* sector 1 = 248 pages * 264 bytes/page
|
|
*/
|
|
.name = "bookkeeping", /* 66 KB */
|
|
.offset = 0,
|
|
.size = (8 + 248) * 264,
|
|
/* .mask_flags = MTD_WRITEABLE, */
|
|
}, {
|
|
/* sector 2 = 256 pages * 264 bytes/page
|
|
* sectors 3-5 = 512 pages * 264 bytes/page
|
|
*/
|
|
.name = "filesystem", /* 462 KB */
|
|
.offset = MTDPART_OFS_APPEND,
|
|
.size = MTDPART_SIZ_FULL,
|
|
} };
|
|
|
|
static struct flash_platform_data flash = {
|
|
.name = "butterflash",
|
|
.parts = partitions,
|
|
.nr_parts = ARRAY_SIZE(partitions),
|
|
};
|
|
|
|
|
|
/* 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;
|
|
master->num_chipselect = 2;
|
|
|
|
pp->bitbang.master = 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, "mtd_dataflash");
|
|
pp->info[0].platform_data = &flash;
|
|
pp->info[0].chip_select = 1;
|
|
pp->info[0].controller_data = pp;
|
|
pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
|
|
if (pp->dataflash)
|
|
pr_debug("%s: dataflash at %s\n", p->name,
|
|
dev_name(&pp->dataflash->dev));
|
|
|
|
pr_info("%s: AVR Butterfly\n", p->name);
|
|
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;
|
|
|
|
/* 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;
|
|
butterfly = NULL;
|
|
|
|
/* stop() unregisters child devices too */
|
|
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 AVR Butterfly");
|
|
MODULE_LICENSE("GPL");
|