Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

[linux-2.6-omap-h63xx.git] / drivers / spi / spi.c

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index c3219b29b5ac70b87190c36b195c4a6139dc385b..e84d21597943d85d1752270526f43232221f1e7c 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -23,6 +23,7 @@
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/cache.h>
+#include <linux/mutex.h>
 #include <linux/spi/spi.h>
 
 
@@ -185,7 +186,7 @@ struct boardinfo {
 };
 
 static LIST_HEAD(board_list);
-static DECLARE_MUTEX(board_lock);
+static DEFINE_MUTEX(board_lock);
 
 
 /**
@@ -199,6 +200,8 @@ static DECLARE_MUTEX(board_lock);
  * platforms may not be able to use spi_register_board_info though, and
  * this is exported so that for example a USB or parport based adapter
  * driver could add devices (which it would learn about out-of-band).
+ *
+ * Returns the new device, or NULL.
  */
 struct spi_device *spi_new_device(struct spi_master *master,
                                  struct spi_board_info *chip)
@@ -207,7 +210,20 @@ struct spi_device *spi_new_device(struct spi_master *master,
        struct device           *dev = master->cdev.dev;
        int                     status;
 
-       /* NOTE:  caller did any chip->bus_num checks necessary */
+       /* NOTE:  caller did any chip->bus_num checks necessary.
+        *
+        * Also, unless we change the return value convention to use
+        * error-or-pointer (not NULL-or-pointer), troubleshootability
+        * suggests syslogged diagnostics are best here (ugh).
+        */
+
+       /* Chipselects are numbered 0..max; validate. */
+       if (chip->chip_select >= master->num_chipselect) {
+               dev_err(dev, "cs%d > max %d\n",
+                       chip->chip_select,
+                       master->num_chipselect);
+               return NULL;
+       }
 
        if (!spi_master_get(master))
                return NULL;
@@ -235,10 +251,10 @@ struct spi_device *spi_new_device(struct spi_master *master,
        proxy->controller_state = NULL;
        proxy->dev.release = spidev_release;
 
-       /* drivers may modify this default i/o setup */
+       /* drivers may modify this initial i/o setup */
        status = master->setup(proxy);
        if (status < 0) {
-               dev_dbg(dev, "can't %s %s, status %d\n",
+               dev_err(dev, "can't %s %s, status %d\n",
                                "setup", proxy->dev.bus_id, status);
                goto fail;
        }
@@ -248,7 +264,7 @@ struct spi_device *spi_new_device(struct spi_master *master,
         */
        status = device_register(&proxy->dev);
        if (status < 0) {
-               dev_dbg(dev, "can't %s %s, status %d\n",
+               dev_err(dev, "can't %s %s, status %d\n",
                                "add", proxy->dev.bus_id, status);
                goto fail;
        }
@@ -292,9 +308,9 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n)
        bi->n_board_info = n;
        memcpy(bi->board_info, info, n * sizeof *info);
 
-       down(&board_lock);
+       mutex_lock(&board_lock);
        list_add_tail(&bi->list, &board_list);
-       up(&board_lock);
+       mutex_unlock(&board_lock);
        return 0;
 }
 
@@ -302,13 +318,11 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n)
  * creates board info from kernel command lines
  */
 
-static void __init_or_module
-scan_boardinfo(struct spi_master *master)
+static void scan_boardinfo(struct spi_master *master)
 {
        struct boardinfo        *bi;
-       struct device           *dev = master->cdev.dev;
 
-       down(&board_lock);
+       mutex_lock(&board_lock);
        list_for_each_entry(bi, &board_list, list) {
                struct spi_board_info   *chip = bi->board_info;
                unsigned                n;
@@ -316,21 +330,13 @@ scan_boardinfo(struct spi_master *master)
                for (n = bi->n_board_info; n > 0; n--, chip++) {
                        if (chip->bus_num != master->bus_num)
                                continue;
-                       /* some controllers only have one chip, so they
-                        * might not use chipselects.  otherwise, the
-                        * chipselects are numbered 0..max.
+                       /* NOTE: this relies on spi_new_device to
+                        * issue diagnostics when given bogus inputs
                         */
-                       if (chip->chip_select >= master->num_chipselect
-                                       && master->num_chipselect) {
-                               dev_dbg(dev, "cs%d > max %d\n",
-                                       chip->chip_select,
-                                       master->num_chipselect);
-                               continue;
-                       }
                        (void) spi_new_device(master, chip);
                }
        }
-       up(&board_lock);
+       mutex_unlock(&board_lock);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -411,7 +417,7 @@ EXPORT_SYMBOL_GPL(spi_alloc_master);
  */
 int spi_register_master(struct spi_master *master)
 {
-       static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<16) - 1);
+       static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
        struct device           *dev = master->cdev.dev;
        int                     status = -ENODEV;
        int                     dynamic = 0;
@@ -419,8 +425,17 @@ int spi_register_master(struct spi_master *master)
        if (!dev)
                return -ENODEV;
 
+       /* even if it's just one always-selected device, there must
+        * be at least one chipselect
+        */
+       if (master->num_chipselect == 0)
+               return -EINVAL;
+
        /* convention:  dynamically assigned bus IDs count down from the max */
        if (master->bus_num < 0) {
+               /* FIXME switch to an IDR based scheme, something like
+                * I2C now uses, so we can't run out of "dynamic" IDs
+                */
                master->bus_num = atomic_dec_return(&dyn_bus_id);
                dynamic = 1;
        }