dm: spi: Check cs number before accessing slaves

Add chip select number check in spi_find_chip_select().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # SoPine

diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
index 0ca108e..5ced890 100644 (file)
--- a/drivers/spi/spi-uclass.c
+++ b/drivers/spi/spi-uclass.c
@@ -224,7 +224,32 @@ int spi_chip_select(struct udevice *dev)
 
 int spi_find_chip_select(struct udevice *bus, int cs, struct udevice **devp)
 {
+       struct dm_spi_ops *ops;
+       struct spi_cs_info info;
        struct udevice *dev;
+       int ret;
+
+       /*
+        * Ask the driver. For the moment we don't have CS info.
+        * When we do we could provide the driver with a helper function
+        * to figure out what chip selects are valid, or just handle the
+        * request.
+        */
+       ops = spi_get_ops(bus);
+       if (ops->cs_info) {
+               ret = ops->cs_info(bus, cs, &info);
+       } else {
+               /*
+                * We could assume there is at least one valid chip select.
+                * The driver didn't care enough to tell us.
+                */
+               ret = 0;
+       }
+
+       if (ret) {
+               printf("Invalid cs %d (err=%d)\n", cs, ret);
+               return ret;
+       }
 
        for (device_find_first_child(bus, &dev); dev;
             device_find_next_child(&dev)) {
@@ -259,7 +284,6 @@ int spi_cs_is_valid(unsigned int busnum, unsigned int cs)
 int spi_cs_info(struct udevice *bus, uint cs, struct spi_cs_info *info)
 {
        struct spi_cs_info local_info;
-       struct dm_spi_ops *ops;
        int ret;
 
        if (!info)
@@ -268,24 +292,7 @@ int spi_cs_info(struct udevice *bus, uint cs, struct spi_cs_info *info)
        /* If there is a device attached, return it */
        info->dev = NULL;
        ret = spi_find_chip_select(bus, cs, &info->dev);
-       if (!ret)
-               return 0;
-
-       /*
-        * Otherwise ask the driver. For the moment we don't have CS info.
-        * When we do we could provide the driver with a helper function
-        * to figure out what chip selects are valid, or just handle the
-        * request.
-        */
-       ops = spi_get_ops(bus);
-       if (ops->cs_info)
-               return ops->cs_info(bus, cs, info);
-
-       /*
-        * We could assume there is at least one valid chip select.
-        * The driver didn't care enough to tell us.
-        */
-       return 0;
+       return ret == -ENODEV ? 0 : ret;
 }
 
 int spi_find_bus_and_cs(int busnum, int cs, struct udevice **busp,

diff --git a/include/spi.h b/include/spi.h
index ba2c840..18a0312 100644 (file)
--- a/include/spi.h
+++ b/include/spi.h
@@ -561,7 +561,8 @@ int spi_chip_select(struct udevice *slave);
  * @bus:       SPI bus to search
  * @cs:                Chip select to look for
  * @devp:      Returns the slave device if found
- * @return 0 if found, -ENODEV on error
+ * @return 0 if found, -EINVAL if cs is invalid, -ENODEV if no device attached,
+ *        other -ve value on error
  */
 int spi_find_chip_select(struct udevice *bus, int cs, struct udevice **devp);