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linux/drivers/spi/omap_uwire.c
David Brownell d1e44d9ce8 SPI driver runtime footprint shrinkage 
Shrink the runtime footprint of various SPI drivers:

  - Move the probe() routine into the init section where practical,
    using platform_driver_probe() to make that safe.  This often saves
    around 1KB.  Using platform_driver_probe() can also be a correctness
    fix, if the probe routine is already marked __init but the driver
    struct keeps a dangling pointer to it after init section removal.

  - Likewise move remove() routines into the exit sections.

These changes would be inappropriate iff the platform devices were
actually hotpluggable (e.g. they're found on optional addon cards,
or in an FPGA that's dynamically reprogrammed).  In these cases,
that's not the situation; it's an SOC controller and the only device
is initialized before these drivers.

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>
2007-10-16 09:43:09 -07:00

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/*
* omap_uwire.c -- MicroWire interface driver for OMAP
*
* Copyright 2003 MontaVista Software Inc. <source@mvista.com>
*
* Ported to 2.6 OMAP uwire interface.
* Copyright (C) 2004 Texas Instruments.
*
* Generalization patches by Juha Yrjola <juha.yrjola@nokia.com>
*
* Copyright (C) 2005 David Brownell (ported to 2.6 SPI interface)
* Copyright (C) 2006 Nokia
*
* Many updates by Imre Deak <imre.deak@nokia.com>
*
* 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 SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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/platform_device.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/mach-types.h>
#include <asm/arch/mux.h>
#include <asm/arch/omap730.h> /* OMAP730_IO_CONF registers */
/* FIXME address is now a platform device resource,
* and irqs should show there too...
*/
#define UWIRE_BASE_PHYS 0xFFFB3000
#define UWIRE_BASE ((void *__iomem)IO_ADDRESS(UWIRE_BASE_PHYS))
/* uWire Registers: */
#define UWIRE_IO_SIZE 0x20
#define UWIRE_TDR 0x00
#define UWIRE_RDR 0x00
#define UWIRE_CSR 0x01
#define UWIRE_SR1 0x02
#define UWIRE_SR2 0x03
#define UWIRE_SR3 0x04
#define UWIRE_SR4 0x05
#define UWIRE_SR5 0x06
/* CSR bits */
#define RDRB (1 << 15)
#define CSRB (1 << 14)
#define START (1 << 13)
#define CS_CMD (1 << 12)
/* SR1 or SR2 bits */
#define UWIRE_READ_FALLING_EDGE 0x0001
#define UWIRE_READ_RISING_EDGE 0x0000
#define UWIRE_WRITE_FALLING_EDGE 0x0000
#define UWIRE_WRITE_RISING_EDGE 0x0002
#define UWIRE_CS_ACTIVE_LOW 0x0000
#define UWIRE_CS_ACTIVE_HIGH 0x0004
#define UWIRE_FREQ_DIV_2 0x0000
#define UWIRE_FREQ_DIV_4 0x0008
#define UWIRE_FREQ_DIV_8 0x0010
#define UWIRE_CHK_READY 0x0020
#define UWIRE_CLK_INVERTED 0x0040
struct uwire_spi {
struct spi_bitbang bitbang;
struct clk *ck;
};
struct uwire_state {
unsigned bits_per_word;
unsigned div1_idx;
};
/* REVISIT compile time constant for idx_shift? */
static unsigned int uwire_idx_shift;
static inline void uwire_write_reg(int idx, u16 val)
{
__raw_writew(val, UWIRE_BASE + (idx << uwire_idx_shift));
}
static inline u16 uwire_read_reg(int idx)
{
return __raw_readw(UWIRE_BASE + (idx << uwire_idx_shift));
}
static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags)
{
u16 w, val = 0;
int shift, reg;
if (flags & UWIRE_CLK_INVERTED)
val ^= 0x03;
val = flags & 0x3f;
if (cs & 1)
shift = 6;
else
shift = 0;
if (cs <= 1)
reg = UWIRE_SR1;
else
reg = UWIRE_SR2;
w = uwire_read_reg(reg);
w &= ~(0x3f << shift);
w |= val << shift;
uwire_write_reg(reg, w);
}
static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch)
{
u16 w;
int c = 0;
unsigned long max_jiffies = jiffies + HZ;
for (;;) {
w = uwire_read_reg(UWIRE_CSR);
if ((w & mask) == val)
break;
if (time_after(jiffies, max_jiffies)) {
printk(KERN_ERR "%s: timeout. reg=%#06x "
"mask=%#06x val=%#06x\n",
__FUNCTION__, w, mask, val);
return -1;
}
c++;
if (might_not_catch && c > 64)
break;
}
return 0;
}
static void uwire_set_clk1_div(int div1_idx)
{
u16 w;
w = uwire_read_reg(UWIRE_SR3);
w &= ~(0x03 << 1);
w |= div1_idx << 1;
uwire_write_reg(UWIRE_SR3, w);
}
static void uwire_chipselect(struct spi_device *spi, int value)
{
struct uwire_state *ust = spi->controller_state;
u16 w;
int old_cs;
BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0));
w = uwire_read_reg(UWIRE_CSR);
old_cs = (w >> 10) & 0x03;
if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) {
/* Deselect this CS, or the previous CS */
w &= ~CS_CMD;
uwire_write_reg(UWIRE_CSR, w);
}
/* activate specfied chipselect */
if (value == BITBANG_CS_ACTIVE) {
uwire_set_clk1_div(ust->div1_idx);
/* invert clock? */
if (spi->mode & SPI_CPOL)
uwire_write_reg(UWIRE_SR4, 1);
else
uwire_write_reg(UWIRE_SR4, 0);
w = spi->chip_select << 10;
w |= CS_CMD;
uwire_write_reg(UWIRE_CSR, w);
}
}
static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
{
struct uwire_state *ust = spi->controller_state;
unsigned len = t->len;
unsigned bits = ust->bits_per_word;
unsigned bytes;
u16 val, w;
int status = 0;;
if (!t->tx_buf && !t->rx_buf)
return 0;
/* Microwire doesn't read and write concurrently */
if (t->tx_buf && t->rx_buf)
return -EPERM;
w = spi->chip_select << 10;
w |= CS_CMD;
if (t->tx_buf) {
const u8 *buf = t->tx_buf;
/* NOTE: DMA could be used for TX transfers */
/* write one or two bytes at a time */
while (len >= 1) {
/* tx bit 15 is first sent; we byteswap multibyte words
* (msb-first) on the way out from memory.
*/
val = *buf++;
if (bits > 8) {
bytes = 2;
val |= *buf++ << 8;
} else
bytes = 1;
val <<= 16 - bits;
#ifdef VERBOSE
pr_debug("%s: write-%d =%04x\n",
spi->dev.bus_id, bits, val);
#endif
if (wait_uwire_csr_flag(CSRB, 0, 0))
goto eio;
uwire_write_reg(UWIRE_TDR, val);
/* start write */
val = START | w | (bits << 5);
uwire_write_reg(UWIRE_CSR, val);
len -= bytes;
/* Wait till write actually starts.
* This is needed with MPU clock 60+ MHz.
* REVISIT: we may not have time to catch it...
*/
if (wait_uwire_csr_flag(CSRB, CSRB, 1))
goto eio;
status += bytes;
}
/* REVISIT: save this for later to get more i/o overlap */
if (wait_uwire_csr_flag(CSRB, 0, 0))
goto eio;
} else if (t->rx_buf) {
u8 *buf = t->rx_buf;
/* read one or two bytes at a time */
while (len) {
if (bits > 8) {
bytes = 2;
} else
bytes = 1;
/* start read */
val = START | w | (bits << 0);
uwire_write_reg(UWIRE_CSR, val);
len -= bytes;
/* Wait till read actually starts */
(void) wait_uwire_csr_flag(CSRB, CSRB, 1);
if (wait_uwire_csr_flag(RDRB | CSRB,
RDRB, 0))
goto eio;
/* rx bit 0 is last received; multibyte words will
* be properly byteswapped on the way to memory.
*/
val = uwire_read_reg(UWIRE_RDR);
val &= (1 << bits) - 1;
*buf++ = (u8) val;
if (bytes == 2)
*buf++ = val >> 8;
status += bytes;
#ifdef VERBOSE
pr_debug("%s: read-%d =%04x\n",
spi->dev.bus_id, bits, val);
#endif
}
}
return status;
eio:
return -EIO;
}
static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct uwire_state *ust = spi->controller_state;
struct uwire_spi *uwire;
unsigned flags = 0;
unsigned bits;
unsigned hz;
unsigned long rate;
int div1_idx;
int div1;
int div2;
int status;
uwire = spi_master_get_devdata(spi->master);
if (spi->chip_select > 3) {
pr_debug("%s: cs%d?\n", spi->dev.bus_id, spi->chip_select);
status = -ENODEV;
goto done;
}
bits = spi->bits_per_word;
if (t != NULL && t->bits_per_word)
bits = t->bits_per_word;
if (!bits)
bits = 8;
if (bits > 16) {
pr_debug("%s: wordsize %d?\n", spi->dev.bus_id, bits);
status = -ENODEV;
goto done;
}
ust->bits_per_word = bits;
/* mode 0..3, clock inverted separately;
* standard nCS signaling;
* don't treat DI=high as "not ready"
*/
if (spi->mode & SPI_CS_HIGH)
flags |= UWIRE_CS_ACTIVE_HIGH;
if (spi->mode & SPI_CPOL)
flags |= UWIRE_CLK_INVERTED;
switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
case SPI_MODE_0:
case SPI_MODE_3:
flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE;
break;
case SPI_MODE_1:
case SPI_MODE_2:
flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE;
break;
}
/* assume it's already enabled */
rate = clk_get_rate(uwire->ck);
hz = spi->max_speed_hz;
if (t != NULL && t->speed_hz)
hz = t->speed_hz;
if (!hz) {
pr_debug("%s: zero speed?\n", spi->dev.bus_id);
status = -EINVAL;
goto done;
}
/* F_INT = mpu_xor_clk / DIV1 */
for (div1_idx = 0; div1_idx < 4; div1_idx++) {
switch (div1_idx) {
case 0:
div1 = 2;
break;
case 1:
div1 = 4;
break;
case 2:
div1 = 7;
break;
default:
case 3:
div1 = 10;
break;
}
div2 = (rate / div1 + hz - 1) / hz;
if (div2 <= 8)
break;
}
if (div1_idx == 4) {
pr_debug("%s: lowest clock %ld, need %d\n",
spi->dev.bus_id, rate / 10 / 8, hz);
status = -EDOM;
goto done;
}
/* we have to cache this and reset in uwire_chipselect as this is a
* global parameter and another uwire device can change it under
* us */
ust->div1_idx = div1_idx;
uwire_set_clk1_div(div1_idx);
rate /= div1;
switch (div2) {
case 0:
case 1:
case 2:
flags |= UWIRE_FREQ_DIV_2;
rate /= 2;
break;
case 3:
case 4:
flags |= UWIRE_FREQ_DIV_4;
rate /= 4;
break;
case 5:
case 6:
case 7:
case 8:
flags |= UWIRE_FREQ_DIV_8;
rate /= 8;
break;
}
omap_uwire_configure_mode(spi->chip_select, flags);
pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n",
__FUNCTION__, flags,
clk_get_rate(uwire->ck) / 1000,
rate / 1000);
status = 0;
done:
return status;
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
static int uwire_setup(struct spi_device *spi)
{
struct uwire_state *ust = spi->controller_state;
if (spi->mode & ~MODEBITS) {
dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return -EINVAL;
}
if (ust == NULL) {
ust = kzalloc(sizeof(*ust), GFP_KERNEL);
if (ust == NULL)
return -ENOMEM;
spi->controller_state = ust;
}
return uwire_setup_transfer(spi, NULL);
}
static void uwire_cleanup(struct spi_device *spi)
{
kfree(spi->controller_state);
}
static void uwire_off(struct uwire_spi *uwire)
{
uwire_write_reg(UWIRE_SR3, 0);
clk_disable(uwire->ck);
clk_put(uwire->ck);
spi_master_put(uwire->bitbang.master);
}
static int __init uwire_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct uwire_spi *uwire;
int status;
master = spi_alloc_master(&pdev->dev, sizeof *uwire);
if (!master)
return -ENODEV;
uwire = spi_master_get_devdata(master);
dev_set_drvdata(&pdev->dev, uwire);
uwire->ck = clk_get(&pdev->dev, "armxor_ck");
if (!uwire->ck || IS_ERR(uwire->ck)) {
dev_dbg(&pdev->dev, "no mpu_xor_clk ?\n");
spi_master_put(master);
return -ENODEV;
}
clk_enable(uwire->ck);
if (cpu_is_omap730())
uwire_idx_shift = 1;
else
uwire_idx_shift = 2;
uwire_write_reg(UWIRE_SR3, 1);
master->bus_num = 2; /* "official" */
master->num_chipselect = 4;
master->setup = uwire_setup;
master->cleanup = uwire_cleanup;
uwire->bitbang.master = master;
uwire->bitbang.chipselect = uwire_chipselect;
uwire->bitbang.setup_transfer = uwire_setup_transfer;
uwire->bitbang.txrx_bufs = uwire_txrx;
status = spi_bitbang_start(&uwire->bitbang);
if (status < 0)
uwire_off(uwire);
return status;
}
static int __exit uwire_remove(struct platform_device *pdev)
{
struct uwire_spi *uwire = dev_get_drvdata(&pdev->dev);
int status;
// FIXME remove all child devices, somewhere ...
status = spi_bitbang_stop(&uwire->bitbang);
uwire_off(uwire);
return status;
}
static struct platform_driver uwire_driver = {
.driver = {
.name = "omap_uwire",
.bus = &platform_bus_type,
.owner = THIS_MODULE,
},
.remove = __exit_p(uwire_remove),
// suspend ... unuse ck
// resume ... use ck
};
static int __init omap_uwire_init(void)
{
/* FIXME move these into the relevant board init code. also, include
* H3 support; it uses tsc2101 like H2 (on a different chipselect).
*/
if (machine_is_omap_h2()) {
/* defaults: W21 SDO, U18 SDI, V19 SCL */
omap_cfg_reg(N14_1610_UWIRE_CS0);
omap_cfg_reg(N15_1610_UWIRE_CS1);
}
if (machine_is_omap_perseus2()) {
/* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */
int val = omap_readl(OMAP730_IO_CONF_9) & ~0x00EEE000;
omap_writel(val | 0x00AAA000, OMAP730_IO_CONF_9);
}
return platform_driver_probe(&uwire_driver, uwire_probe);
}
static void __exit omap_uwire_exit(void)
{
platform_driver_unregister(&uwire_driver);
}
subsys_initcall(omap_uwire_init);
module_exit(omap_uwire_exit);
MODULE_LICENSE("GPL");
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