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>

1 files changed, 60 insertions, 4 deletions

diff --git a/drivers/spi/mpc52xx_spi.c b/drivers/spi/mpc52xx_spi.c
index 64862cfda19e..97beba2895e7 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);