dm: core: Add a few more specific child-finding functions

Add two functions which can find a child device by uclass or by name.
The first is useful with Multi-Function-Devices (MFDs) to find one of a
particular type. The second is useful when only the name is known.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/core/device.c b/drivers/core/device.c
index 47a697f3e5c3fa0329816db779bcf67129742431..836bcadced508ddc0864827c0f0a5e8d1ca41bd3 100644 (file)
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -699,6 +699,40 @@ int device_find_first_inactive_child(struct udevice *parent,
        return -ENODEV;
 }
 
+int device_find_first_child_by_uclass(struct udevice *parent,
+                                     enum uclass_id uclass_id,
+                                     struct udevice **devp)
+{
+       struct udevice *dev;
+
+       *devp = NULL;
+       list_for_each_entry(dev, &parent->child_head, sibling_node) {
+               if (device_get_uclass_id(dev) == uclass_id) {
+                       *devp = dev;
+                       return 0;
+               }
+       }
+
+       return -ENODEV;
+}
+
+int device_find_child_by_name(struct udevice *parent, const char *name,
+                             struct udevice **devp)
+{
+       struct udevice *dev;
+
+       *devp = NULL;
+
+       list_for_each_entry(dev, &parent->child_head, sibling_node) {
+               if (!strcmp(dev->name, name)) {
+                       *devp = dev;
+                       return 0;
+               }
+       }
+
+       return -ENODEV;
+}
+
 struct udevice *dev_get_parent(const struct udevice *child)
 {
        return child->parent;

diff --git a/include/dm/device.h b/include/dm/device.h
index 847934425bbc0a03fbbb84226687f51a25fb85e4..27a6d7b9fdb0da75049a285bb14fb562fca710c3 100644 (file)
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -525,6 +525,8 @@ int device_find_next_child(struct udevice **devp);
  * This is used to locate an existing child of a device which is of a given
  * uclass.
  *
+ * The device is NOT probed
+ *
  * @parent:    Parent device to search
  * @uclass_id: Uclass to look for
  * @devp:      Returns device found, if any
@@ -534,6 +536,29 @@ int device_find_first_inactive_child(struct udevice *parent,
                                     enum uclass_id uclass_id,
                                     struct udevice **devp);
 
+/**
+ * device_find_first_child_by_uclass() - Find the first child of a device in uc
+ *
+ * @parent: Parent device to search
+ * @uclass_id: Uclass to look for
+ * @devp: Returns first child device in that uclass, if any
+ * @return 0 if found, else -ENODEV
+ */
+int device_find_first_child_by_uclass(struct udevice *parent,
+                                     enum uclass_id uclass_id,
+                                     struct udevice **devp);
+
+/**
+ * device_find_child_by_name() - Find a child by device name
+ *
+ * @parent:    Parent device to search
+ * @name:      Name to look for
+ * @devp:      Returns device found, if any
+ * @return 0 if found, else -ENODEV
+ */
+int device_find_child_by_name(struct udevice *parent, const char *name,
+                             struct udevice **devp);
+
 /**
  * device_has_children() - check if a device has any children
  *

diff --git a/test/dm/test-fdt.c b/test/dm/test-fdt.c
index b70e3fa18ac3b7d4a8aee240d196cc42f8921275..0fbd9be765a19d6e9e349db6d2e94b07260bf248 100644 (file)
--- a/test/dm/test-fdt.c
+++ b/test/dm/test-fdt.c
@@ -631,3 +631,30 @@ static int dm_test_fdt_phandle(struct unit_test_state *uts)
        return 0;
 }
 DM_TEST(dm_test_fdt_phandle, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test device_find_first_child_by_uclass() */
+static int dm_test_first_child(struct unit_test_state *uts)
+{
+       struct udevice *i2c, *dev, *dev2;
+
+       ut_assertok(uclass_first_device_err(UCLASS_I2C, &i2c));
+       ut_assertok(device_find_first_child_by_uclass(i2c, UCLASS_RTC, &dev));
+       ut_asserteq_str("rtc@43", dev->name);
+       ut_assertok(device_find_child_by_name(i2c, "rtc@43", &dev2));
+       ut_asserteq_ptr(dev, dev2);
+       ut_assertok(device_find_child_by_name(i2c, "rtc@61", &dev2));
+       ut_asserteq_str("rtc@61", dev2->name);
+
+       ut_assertok(device_find_first_child_by_uclass(i2c, UCLASS_I2C_EEPROM,
+                                                     &dev));
+       ut_asserteq_str("eeprom@2c", dev->name);
+       ut_assertok(device_find_child_by_name(i2c, "eeprom@2c", &dev2));
+       ut_asserteq_ptr(dev, dev2);
+
+       ut_asserteq(-ENODEV, device_find_first_child_by_uclass(i2c,
+                                                       UCLASS_VIDEO, &dev));
+       ut_asserteq(-ENODEV, device_find_child_by_name(i2c, "missing", &dev));
+
+       return 0;
+}
+DM_TEST(dm_test_first_child, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);