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Subject[PATCH 3/3] [V2] mpc52xx_spi: add gpio chipselect
Date
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>
---
drivers/spi/mpc52xx_spi.c | 64 ++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 60 insertions(+), 4 deletions(-)
diff --git a/drivers/spi/mpc52xx_spi.c b/drivers/spi/mpc52xx_spi.c
index 64862cf..97beba2 100644
--- a/drivers/spi/mpc52xx_spi.c
+++ b/drivers/spi/mpc52xx_spi.c
@@ -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);
--
1.6.5.2


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