linux/drivers/spi/spi-ppc4xx.c

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/*
* SPI_PPC4XX SPI controller driver.
*
* Copyright (C) 2007 Gary Jennejohn <garyj@denx.de>
* Copyright 2008 Stefan Roese <sr@denx.de>, DENX Software Engineering
* Copyright 2009 Harris Corporation, Steven A. Falco <sfalco@harris.com>
*
* Based in part on drivers/spi/spi_s3c24xx.c
*
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*/
/*
* The PPC4xx SPI controller has no FIFO so each sent/received byte will
* generate an interrupt to the CPU. This can cause high CPU utilization.
* This driver allows platforms to reduce the interrupt load on the CPU
* during SPI transfers by setting max_speed_hz via the device tree.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <asm/io.h>
#include <asm/dcr.h>
#include <asm/dcr-regs.h>
/* bits in mode register - bit 0 is MSb */
/*
* SPI_PPC4XX_MODE_SCP = 0 means "data latched on trailing edge of clock"
* SPI_PPC4XX_MODE_SCP = 1 means "data latched on leading edge of clock"
* Note: This is the inverse of CPHA.
*/
#define SPI_PPC4XX_MODE_SCP (0x80 >> 3)
/* SPI_PPC4XX_MODE_SPE = 1 means "port enabled" */
#define SPI_PPC4XX_MODE_SPE (0x80 >> 4)
/*
* SPI_PPC4XX_MODE_RD = 0 means "MSB first" - this is the normal mode
* SPI_PPC4XX_MODE_RD = 1 means "LSB first" - this is bit-reversed mode
* Note: This is identical to SPI_LSB_FIRST.
*/
#define SPI_PPC4XX_MODE_RD (0x80 >> 5)
/*
* SPI_PPC4XX_MODE_CI = 0 means "clock idles low"
* SPI_PPC4XX_MODE_CI = 1 means "clock idles high"
* Note: This is identical to CPOL.
*/
#define SPI_PPC4XX_MODE_CI (0x80 >> 6)
/*
* SPI_PPC4XX_MODE_IL = 0 means "loopback disable"
* SPI_PPC4XX_MODE_IL = 1 means "loopback enable"
*/
#define SPI_PPC4XX_MODE_IL (0x80 >> 7)
/* bits in control register */
/* starts a transfer when set */
#define SPI_PPC4XX_CR_STR (0x80 >> 7)
/* bits in status register */
/* port is busy with a transfer */
#define SPI_PPC4XX_SR_BSY (0x80 >> 6)
/* RxD ready */
#define SPI_PPC4XX_SR_RBR (0x80 >> 7)
/* clock settings (SCP and CI) for various SPI modes */
#define SPI_CLK_MODE0 (SPI_PPC4XX_MODE_SCP | 0)
#define SPI_CLK_MODE1 (0 | 0)
#define SPI_CLK_MODE2 (SPI_PPC4XX_MODE_SCP | SPI_PPC4XX_MODE_CI)
#define SPI_CLK_MODE3 (0 | SPI_PPC4XX_MODE_CI)
#define DRIVER_NAME "spi_ppc4xx_of"
struct spi_ppc4xx_regs {
u8 mode;
u8 rxd;
u8 txd;
u8 cr;
u8 sr;
u8 dummy;
/*
* Clock divisor modulus register
* This uses the following formula:
* SCPClkOut = OPBCLK/(4(CDM + 1))
* or
* CDM = (OPBCLK/4*SCPClkOut) - 1
* bit 0 is the MSb!
*/
u8 cdm;
};
/* SPI Controller driver's private data. */
struct ppc4xx_spi {
/* bitbang has to be first */
struct spi_bitbang bitbang;
struct completion done;
u64 mapbase;
u64 mapsize;
int irqnum;
/* need this to set the SPI clock */
unsigned int opb_freq;
/* for transfers */
int len;
int count;
/* data buffers */
const unsigned char *tx;
unsigned char *rx;
int *gpios;
struct spi_ppc4xx_regs __iomem *regs; /* pointer to the registers */
struct spi_master *master;
struct device *dev;
};
/* need this so we can set the clock in the chipselect routine */
struct spi_ppc4xx_cs {
u8 mode;
};
static int spi_ppc4xx_txrx(struct spi_device *spi, struct spi_transfer *t)
{
struct ppc4xx_spi *hw;
u8 data;
dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
t->tx_buf, t->rx_buf, t->len);
hw = spi_master_get_devdata(spi->master);
hw->tx = t->tx_buf;
hw->rx = t->rx_buf;
hw->len = t->len;
hw->count = 0;
/* send the first byte */
data = hw->tx ? hw->tx[0] : 0;
out_8(&hw->regs->txd, data);
out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
wait_for_completion(&hw->done);
return hw->count;
}
static int spi_ppc4xx_setupxfer(struct spi_device *spi, struct spi_transfer *t)
{
struct ppc4xx_spi *hw = spi_master_get_devdata(spi->master);
struct spi_ppc4xx_cs *cs = spi->controller_state;
int scr;
u8 cdm = 0;
u32 speed;
u8 bits_per_word;
/* Start with the generic configuration for this device. */
bits_per_word = spi->bits_per_word;
speed = spi->max_speed_hz;
/*
* Modify the configuration if the transfer overrides it. Do not allow
* the transfer to overwrite the generic configuration with zeros.
*/
if (t) {
if (t->bits_per_word)
bits_per_word = t->bits_per_word;
if (t->speed_hz)
speed = min(t->speed_hz, spi->max_speed_hz);
}
if (!speed || (speed > spi->max_speed_hz)) {
dev_err(&spi->dev, "invalid speed_hz (%d)\n", speed);
return -EINVAL;
}
/* Write new configuration */
out_8(&hw->regs->mode, cs->mode);
/* Set the clock */
/* opb_freq was already divided by 4 */
scr = (hw->opb_freq / speed) - 1;
if (scr > 0)
cdm = min(scr, 0xff);
dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", cdm, speed);
if (in_8(&hw->regs->cdm) != cdm)
out_8(&hw->regs->cdm, cdm);
spin_lock(&hw->bitbang.lock);
if (!hw->bitbang.busy) {
hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
/* Need to ndelay here? */
}
spin_unlock(&hw->bitbang.lock);
return 0;
}
static int spi_ppc4xx_setup(struct spi_device *spi)
{
struct spi_ppc4xx_cs *cs = spi->controller_state;
if (!spi->max_speed_hz) {
dev_err(&spi->dev, "invalid max_speed_hz (must be non-zero)\n");
return -EINVAL;
}
if (cs == NULL) {
cs = kzalloc(sizeof *cs, GFP_KERNEL);
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
}
/*
* We set all bits of the SPI0_MODE register, so,
* no need to read-modify-write
*/
cs->mode = SPI_PPC4XX_MODE_SPE;
switch (spi->mode & (SPI_CPHA | SPI_CPOL)) {
case SPI_MODE_0:
cs->mode |= SPI_CLK_MODE0;
break;
case SPI_MODE_1:
cs->mode |= SPI_CLK_MODE1;
break;
case SPI_MODE_2:
cs->mode |= SPI_CLK_MODE2;
break;
case SPI_MODE_3:
cs->mode |= SPI_CLK_MODE3;
break;
}
if (spi->mode & SPI_LSB_FIRST)
cs->mode |= SPI_PPC4XX_MODE_RD;
return 0;
}
static void spi_ppc4xx_chipsel(struct spi_device *spi, int value)
{
struct ppc4xx_spi *hw = spi_master_get_devdata(spi->master);
unsigned int cs = spi->chip_select;
unsigned int cspol;
/*
* If there are no chip selects at all, or if this is the special
* case of a non-existent (dummy) chip select, do nothing.
*/
if (!hw->master->num_chipselect || hw->gpios[cs] == -EEXIST)
return;
cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
if (value == BITBANG_CS_INACTIVE)
cspol = !cspol;
gpio_set_value(hw->gpios[cs], cspol);
}
static irqreturn_t spi_ppc4xx_int(int irq, void *dev_id)
{
struct ppc4xx_spi *hw;
u8 status;
u8 data;
unsigned int count;
hw = (struct ppc4xx_spi *)dev_id;
status = in_8(&hw->regs->sr);
if (!status)
return IRQ_NONE;
/*
* BSY de-asserts one cycle after the transfer is complete. The
* interrupt is asserted after the transfer is complete. The exact
* relationship is not documented, hence this code.
*/
if (unlikely(status & SPI_PPC4XX_SR_BSY)) {
u8 lstatus;
int cnt = 0;
dev_dbg(hw->dev, "got interrupt but spi still busy?\n");
do {
ndelay(10);
lstatus = in_8(&hw->regs->sr);
} while (++cnt < 100 && lstatus & SPI_PPC4XX_SR_BSY);
if (cnt >= 100) {
dev_err(hw->dev, "busywait: too many loops!\n");
complete(&hw->done);
return IRQ_HANDLED;
} else {
/* status is always 1 (RBR) here */
status = in_8(&hw->regs->sr);
dev_dbg(hw->dev, "loops %d status %x\n", cnt, status);
}
}
count = hw->count;
hw->count++;
/* RBR triggered this interrupt. Therefore, data must be ready. */
data = in_8(&hw->regs->rxd);
if (hw->rx)
hw->rx[count] = data;
count++;
if (count < hw->len) {
data = hw->tx ? hw->tx[count] : 0;
out_8(&hw->regs->txd, data);
out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
} else {
complete(&hw->done);
}
return IRQ_HANDLED;
}
static void spi_ppc4xx_cleanup(struct spi_device *spi)
{
kfree(spi->controller_state);
}
static void spi_ppc4xx_enable(struct ppc4xx_spi *hw)
{
/*
* On all 4xx PPC's the SPI bus is shared/multiplexed with
* the 2nd I2C bus. We need to enable the the SPI bus before
* using it.
*/
/* need to clear bit 14 to enable SPC */
dcri_clrset(SDR0, SDR0_PFC1, 0x80000000 >> 14, 0);
}
static void free_gpios(struct ppc4xx_spi *hw)
{
if (hw->master->num_chipselect) {
int i;
for (i = 0; i < hw->master->num_chipselect; i++)
if (gpio_is_valid(hw->gpios[i]))
gpio_free(hw->gpios[i]);
kfree(hw->gpios);
hw->gpios = NULL;
}
}
/*
* platform_device layer stuff...
*/
static int spi_ppc4xx_of_probe(struct platform_device *op)
{
struct ppc4xx_spi *hw;
struct spi_master *master;
struct spi_bitbang *bbp;
struct resource resource;
struct device_node *np = op->dev.of_node;
struct device *dev = &op->dev;
struct device_node *opbnp;
int ret;
int num_gpios;
const unsigned int *clk;
master = spi_alloc_master(dev, sizeof *hw);
if (master == NULL)
return -ENOMEM;
master->dev.of_node = np;
platform_set_drvdata(op, master);
hw = spi_master_get_devdata(master);
hw->master = spi_master_get(master);
hw->dev = dev;
init_completion(&hw->done);
/*
* A count of zero implies a single SPI device without any chip-select.
* Note that of_gpio_count counts all gpios assigned to this spi master.
* This includes both "null" gpio's and real ones.
*/
num_gpios = of_gpio_count(np);
if (num_gpios > 0) {
int i;
hw->gpios = kzalloc(sizeof(int) * num_gpios, GFP_KERNEL);
if (!hw->gpios) {
ret = -ENOMEM;
goto free_master;
}
for (i = 0; i < num_gpios; i++) {
int gpio;
enum of_gpio_flags flags;
gpio = of_get_gpio_flags(np, i, &flags);
hw->gpios[i] = gpio;
if (gpio_is_valid(gpio)) {
/* Real CS - set the initial state. */
ret = gpio_request(gpio, np->name);
if (ret < 0) {
dev_err(dev, "can't request gpio "
"#%d: %d\n", i, ret);
goto free_gpios;
}
gpio_direction_output(gpio,
!!(flags & OF_GPIO_ACTIVE_LOW));
} else if (gpio == -EEXIST) {
; /* No CS, but that's OK. */
} else {
dev_err(dev, "invalid gpio #%d: %d\n", i, gpio);
ret = -EINVAL;
goto free_gpios;
}
}
}
/* Setup the state for the bitbang driver */
bbp = &hw->bitbang;
bbp->master = hw->master;
bbp->setup_transfer = spi_ppc4xx_setupxfer;
bbp->chipselect = spi_ppc4xx_chipsel;
bbp->txrx_bufs = spi_ppc4xx_txrx;
bbp->use_dma = 0;
bbp->master->setup = spi_ppc4xx_setup;
bbp->master->cleanup = spi_ppc4xx_cleanup;
bbp->master->bits_per_word_mask = SPI_BPW_MASK(8);
/* the spi->mode bits understood by this driver: */
bbp->master->mode_bits =
SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST;
/* this many pins in all GPIO controllers */
bbp->master->num_chipselect = num_gpios > 0 ? num_gpios : 0;
/* Get the clock for the OPB */
opbnp = of_find_compatible_node(NULL, NULL, "ibm,opb");
if (opbnp == NULL) {
dev_err(dev, "OPB: cannot find node\n");
ret = -ENODEV;
goto free_gpios;
}
/* Get the clock (Hz) for the OPB */
clk = of_get_property(opbnp, "clock-frequency", NULL);
if (clk == NULL) {
dev_err(dev, "OPB: no clock-frequency property set\n");
of_node_put(opbnp);
ret = -ENODEV;
goto free_gpios;
}
hw->opb_freq = *clk;
hw->opb_freq >>= 2;
of_node_put(opbnp);
ret = of_address_to_resource(np, 0, &resource);
if (ret) {
dev_err(dev, "error while parsing device node resource\n");
goto free_gpios;
}
hw->mapbase = resource.start;
hw->mapsize = resource_size(&resource);
/* Sanity check */
if (hw->mapsize < sizeof(struct spi_ppc4xx_regs)) {
dev_err(dev, "too small to map registers\n");
ret = -EINVAL;
goto free_gpios;
}
/* Request IRQ */
hw->irqnum = irq_of_parse_and_map(np, 0);
ret = request_irq(hw->irqnum, spi_ppc4xx_int,
0, "spi_ppc4xx_of", (void *)hw);
if (ret) {
dev_err(dev, "unable to allocate interrupt\n");
goto free_gpios;
}
if (!request_mem_region(hw->mapbase, hw->mapsize, DRIVER_NAME)) {
dev_err(dev, "resource unavailable\n");
ret = -EBUSY;
goto request_mem_error;
}
hw->regs = ioremap(hw->mapbase, sizeof(struct spi_ppc4xx_regs));
if (!hw->regs) {
dev_err(dev, "unable to memory map registers\n");
ret = -ENXIO;
goto map_io_error;
}
spi_ppc4xx_enable(hw);
/* Finally register our spi controller */
dev->dma_mask = 0;
ret = spi_bitbang_start(bbp);
if (ret) {
dev_err(dev, "failed to register SPI master\n");
goto unmap_regs;
}
dev_info(dev, "driver initialized\n");
return 0;
unmap_regs:
iounmap(hw->regs);
map_io_error:
release_mem_region(hw->mapbase, hw->mapsize);
request_mem_error:
free_irq(hw->irqnum, hw);
free_gpios:
free_gpios(hw);
free_master:
spi_master_put(master);
dev_err(dev, "initialization failed\n");
return ret;
}
static int spi_ppc4xx_of_remove(struct platform_device *op)
{
struct spi_master *master = platform_get_drvdata(op);
struct ppc4xx_spi *hw = spi_master_get_devdata(master);
spi_bitbang_stop(&hw->bitbang);
release_mem_region(hw->mapbase, hw->mapsize);
free_irq(hw->irqnum, hw);
iounmap(hw->regs);
free_gpios(hw);
return 0;
}
static const struct of_device_id spi_ppc4xx_of_match[] = {
{ .compatible = "ibm,ppc4xx-spi", },
{},
};
MODULE_DEVICE_TABLE(of, spi_ppc4xx_of_match);
static struct platform_driver spi_ppc4xx_of_driver = {
.probe = spi_ppc4xx_of_probe,
.remove = spi_ppc4xx_of_remove,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = spi_ppc4xx_of_match,
},
};
module_platform_driver(spi_ppc4xx_of_driver);
MODULE_AUTHOR("Gary Jennejohn & Stefan Roese");
MODULE_DESCRIPTION("Simple PPC4xx SPI Driver");
MODULE_LICENSE("GPL");