clk: add clk_valid()

Add clk_valid() to check for optional clocks are valid.
Call clk_valid() in test/dm/clk.c and add relevant test routine to
sandbox clk tests.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/sandbox/include/asm/clk.h

@@ -138,5 +138,13 @@ int sandbox_clk_test_free(struct udevice *dev);
  * @return:	0 if OK, or a negative error code.
  */
 int sandbox_clk_test_release_bulk(struct udevice *dev);
+/**
+ * sandbox_clk_test_valid - Ask the sandbox clock test device to check its
+ * clocks are valid.
+ *
+ * @dev:	The sandbox clock test (client) devivce.
+ * @return:	0 if OK, or a negative error code.
+ */
+int sandbox_clk_test_valid(struct udevice *dev);
 
 #endif

drivers/clk/clk_sandbox_test.c

@@ -116,6 +116,19 @@ int sandbox_clk_test_release_bulk(struct udevice *dev)
 	return clk_release_bulk(&sbct->bulk);
 }
 
+int sandbox_clk_test_valid(struct udevice *dev)
+{
+	struct sandbox_clk_test *sbct = dev_get_priv(dev);
+	int i;
+
+	for (i = 0; i < SANDBOX_CLK_TEST_ID_COUNT; i++) {
+		if (!clk_valid(&sbct->clks[i]))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
 static const struct udevice_id sandbox_clk_test_ids[] = {
 	{ .compatible = "sandbox,clk-test" },
 	{ }

include/clk.h

@@ -294,4 +294,14 @@ int clk_disable_bulk(struct clk_bulk *bulk);
 
 int soc_clk_dump(void);
 
+/**
+ * clk_valid() - check if clk is valid
+ *
+ * @clk:	the clock to check
+ * @return true if valid, or false
+ */
+static inline bool clk_valid(struct clk *clk)
+{
+	return !!clk->dev;
+}
 #endif

test/dm/clk.c

@@ -28,6 +28,7 @@ static int dm_test_clk(struct unit_test_state *uts)
 	ut_assertok(uclass_get_device_by_name(UCLASS_MISC, "clk-test",
 					      &dev_test));
 	ut_assertok(sandbox_clk_test_get(dev_test));
+	ut_assertok(sandbox_clk_test_valid(dev_test));
 
 	ut_asserteq(1234,
 		    sandbox_clk_test_get_rate(dev_test,