gpio: fix probe() error return in gpio driver probes

A number of drivers in drivers/gpio return -ENODEV when confronted with
missing setup parameters such as the platform data.  However, returning
-ENODEV causes the driver layer to silently ignore the driver as it
assumes the probe did not find anything and was only speculative.

To make life easier to discern why a driver is not being attached, change
to returning -EINVAL, which is a better description of the fact that the
driver data was not valid.

Also add a set of dev_dbg() statements to the error paths to provide an
better explanation of the error as there may be more that one point in the
driver.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/gpio/max7301.c b/drivers/gpio/max7301.c
index 8b24d78..3e7f4e0 100644 (file)
--- a/drivers/gpio/max7301.c
+++ b/drivers/gpio/max7301.c
@@ -217,8 +217,10 @@ static int __devinit max7301_probe(struct spi_device *spi)
        int i, ret;
 
        pdata = spi->dev.platform_data;
-       if (!pdata || !pdata->base)
-               return -ENODEV;
+       if (!pdata || !pdata->base) {
+               dev_dbg(&spi->dev, "incorrect or missing platform data\n");
+               return -EINVAL;
+       }
 
        /*
         * bits_per_word cannot be configured in platform data

diff --git a/drivers/gpio/max732x.c b/drivers/gpio/max732x.c
index 55ae9a4..f786824 100644 (file)
--- a/drivers/gpio/max732x.c
+++ b/drivers/gpio/max732x.c
@@ -267,8 +267,10 @@ static int __devinit max732x_probe(struct i2c_client *client,
        int ret, nr_port;
 
        pdata = client->dev.platform_data;
-       if (pdata == NULL)
-               return -ENODEV;
+       if (pdata == NULL) {
+               dev_dbg(&client->dev, "no platform data\n");
+               return -EINVAL;
+       }
 
        chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
        if (chip == NULL)

diff --git a/drivers/gpio/mcp23s08.c b/drivers/gpio/mcp23s08.c
index 89c1d22..f6fae0e 100644 (file)
--- a/drivers/gpio/mcp23s08.c
+++ b/drivers/gpio/mcp23s08.c
@@ -310,8 +310,10 @@ static int mcp23s08_probe(struct spi_device *spi)
        unsigned                        base;
 
        pdata = spi->dev.platform_data;
-       if (!pdata || !gpio_is_valid(pdata->base))
-               return -ENODEV;
+       if (!pdata || !gpio_is_valid(pdata->base)) {
+               dev_dbg(&spi->dev, "invalid or missing platform data\n");
+               return -EINVAL;
+       }
 
        for (addr = 0; addr < 4; addr++) {
                if (!pdata->chip[addr].is_present)

diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index 37f3538..8dc0164 100644 (file)
--- a/drivers/gpio/pca953x.c
+++ b/drivers/gpio/pca953x.c
@@ -202,8 +202,10 @@ static int __devinit pca953x_probe(struct i2c_client *client,
        int ret;
 
        pdata = client->dev.platform_data;
-       if (pdata == NULL)
-               return -ENODEV;
+       if (pdata == NULL) {
+               dev_dbg(&client->dev, "no platform data\n");
+               return -EINVAL;
+       }
 
        chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
        if (chip == NULL)

diff --git a/drivers/gpio/pcf857x.c b/drivers/gpio/pcf857x.c
index 4bc2070..9525724 100644 (file)
--- a/drivers/gpio/pcf857x.c
+++ b/drivers/gpio/pcf857x.c
@@ -188,8 +188,10 @@ static int pcf857x_probe(struct i2c_client *client,
        int                             status;
 
        pdata = client->dev.platform_data;
-       if (!pdata)
-               return -ENODEV;
+       if (!pdata) {
+               dev_dbg(&client->dev, "no platform data\n");
+               return -EINVAL;
+       }
 
        /* Allocate, initialize, and register this gpio_chip. */
        gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
@@ -248,8 +250,10 @@ static int pcf857x_probe(struct i2c_client *client,
                else
                        status = i2c_read_le16(client);
 
-       } else
-               status = -ENODEV;
+       } else {
+               dev_dbg(&client->dev, "unsupported number of gpios\n");
+               status = -EINVAL;
+       }
 
        if (status < 0)
                goto fail;