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mpc52xx_spi: add gpio chipselect 

This one enables the mpc52xx_spi driver for usage of user defined gpio lines
as chipselect. This way we can control some more spi devices than only one

V2 Changes:
* preinitialize the gpio as output in probe function and call gpio_set_value in
  the chip select function instead of calling direction_output every time.
* initialize the gpio line with output high, since we don't support CS_HIGH
  in the driver currently any way. change gpio value setting to default active
  low in chip select call.
* free the gpio array while error or removing.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Luotao Fu 2009-11-13 10:41:17 +01:00 committed by Grant Likely
parent d65aea99bd
commit b8d4e2ce60
1 changed files with 60 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
drivers/spi/mpc52xx_spi.c
View File

@ -21,6 +21,7 @@
#include <linux/spi/mpc52xx_spi.h>
#include <linux/of_spi.h>
#include <linux/io.h>
#include <linux/of_gpio.h>
#include <asm/time.h>
#include <asm/mpc52xx.h>
@ -79,7 +80,6 @@ struct mpc52xx_spi {
spinlock_t lock;
struct work_struct work;
/* Details of current transfer (length, and buffer pointers) */
struct spi_message *message; /* current message */
struct spi_transfer *transfer; /* current transfer */
@ -89,6 +89,8 @@ struct mpc52xx_spi {
u8 *rx_buf;
const u8 *tx_buf;
int cs_change;
int gpio_cs_count;
unsigned int *gpio_cs;
};
/*
@ -96,7 +98,13 @@ struct mpc52xx_spi {
*/
static void mpc52xx_spi_chipsel(struct mpc52xx_spi *ms, int value)
{
out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
int cs;
if (ms->gpio_cs_count > 0) {
cs = ms->message->spi->chip_select;
gpio_set_value(ms->gpio_cs[cs], value ? 0 : 1);
} else
out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
}
/*
@ -390,8 +398,9 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
struct spi_master *master;
struct mpc52xx_spi *ms;
void __iomem *regs;
int rc;
u8 ctrl1;
int rc, i = 0;
int gpio_cs;
/* MMIO registers */
dev_dbg(&op->dev, "probing mpc5200 SPI device\n");
@ -426,8 +435,8 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
rc = -ENOMEM;
goto err_alloc;
}
master->bus_num = -1;
master->num_chipselect = 1;
master->setup = mpc52xx_spi_setup;
master->transfer = mpc52xx_spi_transfer;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
@ -441,6 +450,40 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
ms->irq1 = irq_of_parse_and_map(op->node, 1);
ms->state = mpc52xx_spi_fsmstate_idle;
ms->ipb_freq = mpc5xxx_get_bus_frequency(op->node);
ms->gpio_cs_count = of_gpio_count(op->node);
if (ms->gpio_cs_count > 0) {
master->num_chipselect = ms->gpio_cs_count;
ms->gpio_cs = kmalloc(ms->gpio_cs_count * sizeof(unsigned int),
GFP_KERNEL);
if (!ms->gpio_cs) {
rc = -ENOMEM;
goto err_alloc;
}
for (i = 0; i < ms->gpio_cs_count; i++) {
gpio_cs = of_get_gpio(op->node, i);
if (gpio_cs < 0) {
dev_err(&op->dev,
"could not parse the gpio field "
"in oftree\n");
rc = -ENODEV;
goto err_gpio;
}
rc = gpio_request(gpio_cs, dev_name(&op->dev));
if (rc) {
dev_err(&op->dev,
"can't request spi cs gpio #%d "
"on gpio line %d\n", i, gpio_cs);
goto err_gpio;
}
gpio_direction_output(gpio_cs, 1);
ms->gpio_cs[i] = gpio_cs;
}
} else
master->num_chipselect = 1;
spin_lock_init(&ms->lock);
INIT_LIST_HEAD(&ms->queue);
INIT_WORK(&ms->work, mpc52xx_spi_wq);
@ -477,6 +520,12 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
err_register:
dev_err(&ms->master->dev, "initialization failed\n");
spi_master_put(master);
err_gpio:
while (i-- > 0)
gpio_free(ms->gpio_cs[i]);
if (ms->gpio_cs != NULL)
kfree(ms->gpio_cs);
err_alloc:
err_init:
iounmap(regs);
@ -487,10 +536,17 @@ static int __devexit mpc52xx_spi_remove(struct of_device *op)
{
struct spi_master *master = dev_get_drvdata(&op->dev);
struct mpc52xx_spi *ms = spi_master_get_devdata(master);
int i;
free_irq(ms->irq0, ms);
free_irq(ms->irq1, ms);
for (i = 0; i < ms->gpio_cs_count; i++)
gpio_free(ms->gpio_cs[i]);
if (ms->gpio_cs != NULL)
kfree(ms->gpio_cs);
spi_unregister_master(master);
spi_master_put(master);
iounmap(ms->regs);