gpio: Make of_count_named_gpios() use new of_count_phandle_with_args()

This patch replaces the horribly coded of_count_named_gpios() with a
call to of_count_phandle_with_args() which is far more efficient. This
also changes the return value of of_gpio_count() & of_gpio_named_count()
from 'unsigned int' to 'int' so that it can return an error code. All
the users of that function are fixed up to correctly handle a negative
return value.

v2: Split GPIO portion into a separate patch

Tested-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>

4 files changed, 10 insertions, 11 deletions

diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index 1a7f6359d998..086a9eef2e05 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -947,12 +947,12 @@ static int of_fsl_spi_get_chipselects(struct device *dev)
         struct device_node *np = dev->of_node;
         struct fsl_spi_platform_data *pdata = dev->platform_data;
         struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
-        unsigned int ngpios;
+        int ngpios;
         int i = 0;
         int ret;
 
         ngpios = of_gpio_count(np);
-        if (!ngpios) {
+        if (ngpios <= 0) {
                 /*
                  * SPI w/o chip-select line. One SPI device is still permitted
                  * though.
diff --git a/drivers/spi/spi-oc-tiny.c b/drivers/spi/spi-oc-tiny.c
index 432e66ec3088..cb2e284bd814 100644
--- a/drivers/spi/spi-oc-tiny.c
+++ b/drivers/spi/spi-oc-tiny.c
@@ -54,7 +54,7 @@ struct tiny_spi {
         unsigned int txc, rxc;
         const u8 *txp;
         u8 *rxp;
-        unsigned int gpio_cs_count;
+        int gpio_cs_count;
         int *gpio_cs;
 };
 
@@ -74,7 +74,7 @@ static void tiny_spi_chipselect(struct spi_device *spi, int is_active)
 {
         struct tiny_spi *hw = tiny_spi_to_hw(spi);
 
-        if (hw->gpio_cs_count) {
+        if (hw->gpio_cs_count > 0) {
                 gpio_set_value(hw->gpio_cs[spi->chip_select],
                         (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
         }
@@ -254,7 +254,7 @@ static int tiny_spi_of_probe(struct platform_device *pdev)
         if (!np)
                 return 0;
         hw->gpio_cs_count = of_gpio_count(np);
-        if (hw->gpio_cs_count) {
+        if (hw->gpio_cs_count > 0) {
                 hw->gpio_cs = devm_kzalloc(&pdev->dev,
                                 hw->gpio_cs_count * sizeof(unsigned int),
                                 GFP_KERNEL);
@@ -352,7 +352,7 @@ static int tiny_spi_probe(struct platform_device *pdev)
                         goto exit_gpio;
                 gpio_direction_output(hw->gpio_cs[i], 1);
         }
-        hw->bitbang.master->num_chipselect = max(1U, hw->gpio_cs_count);
+        hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count);
 
         /* register our spi controller */
         err = spi_bitbang_start(&hw->bitbang);
diff --git a/drivers/spi/spi-ppc4xx.c b/drivers/spi/spi-ppc4xx.c
index 7a85f22b6474..af3e6e756dc9 100644
--- a/drivers/spi/spi-ppc4xx.c
+++ b/drivers/spi/spi-ppc4xx.c
@@ -419,7 +419,7 @@ static int __init spi_ppc4xx_of_probe(struct platform_device *op)
          * This includes both "null" gpio's and real ones.
          */
         num_gpios = of_gpio_count(np);
-        if (num_gpios) {
+        if (num_gpios > 0) {
                 int i;
 
                 hw->gpios = kzalloc(sizeof(int) * num_gpios, GFP_KERNEL);
@@ -471,7 +471,7 @@ static int __init spi_ppc4xx_of_probe(struct platform_device *op)
                 SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST;
 
         /* this many pins in all GPIO controllers */
-        bbp->master->num_chipselect = num_gpios;
+        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");
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 19ee901577da..21c47482d9fd 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1059,15 +1059,14 @@ EXPORT_SYMBOL_GPL(spi_alloc_master);
 #ifdef CONFIG_OF
 static int of_spi_register_master(struct spi_master *master)
 {
-        u16 nb;
-        int i, *cs;
+        int nb, i, *cs;
         struct device_node *np = master->dev.of_node;
 
         if (!np)
                 return 0;
 
         nb = of_gpio_named_count(np, "cs-gpios");
-        master->num_chipselect = max(nb, master->num_chipselect);
+        master->num_chipselect = max(nb, (int)master->num_chipselect);
 
         if (nb < 1)
                 return 0;