This commit adds the clk_get_parent_rate() function, which is responsible
for getting the rate of parent clock.
Unfortunately, u-boot's DM support for getting parent is different
(the parent relationship is in udevice) than the one in common clock
framework (CCF) in Linux.
To alleviate this problem - the clk_get_parent_rate() function has been
introduced to clk-uclass.c.
As written in the in-code comment - some clocks do not set clk->id (and
require it to be set to 0) and hence the standard ckl_{request|get_rate|
free} API is used.
Signed-off-by: Lukasz Majewski <lu...@denx.de>
---
Changes in v2: None
drivers/clk/clk-uclass.c | 41 +++++++++++++++++++++++++++++++++++++++++
include/clk.h | 9 +++++++++
2 files changed, 50 insertions(+)
diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 6d7a514006..f1640dda67 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -340,6 +340,47 @@ ulong clk_get_rate(struct clk *clk)
return ops->get_rate(clk);
}
+ulong clk_get_parent_rate(struct clk *clk)
+{
+ const struct clk_ops *ops;
+ struct udevice *pdev;
+ struct clk pclk;
+ ulong rate;
+ int ret;
+
+ debug("%s(clk=%p)\n", __func__, clk);
+
+ pdev = clk->dev->parent;
+ if (!pdev)
+ return -ENODEV;
+
+ ops = clk_dev_ops(pdev);
+ if (!ops->get_rate)
+ return -ENOSYS;
+
+ /*
+ * We do use memset, clk_{request|get_rate|free}
+ * as there are clocks - like the "fixed" ones, which
+ * doesn't posses the clk wrapper struct (just added to
+ * UCLASS_CLK) and explicitly check if clk->id = 0.
+ *
+ * In fact the "clock" resources (like ops, description)
+ * are accessed via udevice structure (pdev - parent's one)
+ */
+
+ memset(&pclk, 0, sizeof(pclk));
+ ret = clk_request(pdev, &pclk);
+ if (ret) {
+ printf("%s: pclk: %s request failed!\n", __func__, pdev->name);
+ return ret;
+ }
+
+ rate = clk_get_rate(&pclk);
+ clk_free(&pclk);
+
+ return rate;
+}
+
ulong clk_set_rate(struct clk *clk, ulong rate)
{
const struct clk_ops *ops = clk_dev_ops(clk->dev);
diff --git a/include/clk.h b/include/clk.h
index f6fbcc6634..8224295ec3 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -238,6 +238,15 @@ int clk_free(struct clk *clk);
ulong clk_get_rate(struct clk *clk);
/**
+ * clk_get_parent_rate() - Get parent of current clock rate.
+ *
+ * @clk: A clock struct that was previously successfully requested by
+ * clk_request/get_by_*().
+ * @return clock rate in Hz, or -ve error code.
+ */
+ulong clk_get_parent_rate(struct clk *clk);
+
+/**
* clk_set_rate() - Set current clock rate.
*
* @clk: A clock struct that was previously successfully requested by
--
2.11.0
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