It returns the rate which will be set if you ask clk_set_rate() to set that rate. It provides a way to query exactly what rate you'll get if you call clk_set_rate() with that same argument. So essentially, clk_round_rate() and clk_set_rate() are equivalent except the former does not modify the clock hardware in any way.
Signed-off-by: Dario Binacchi dariobin@libero.it Reviewed-by: Simon Glass sjg@chromium.org Reviewed-by: Sean Anderson seanga2@gmail.com
---
Changes in v4: - Update clk_round_rate description. - Add Sean Anderson review.
arch/sandbox/include/asm/clk.h | 9 +++++++++ drivers/clk/clk-uclass.c | 15 +++++++++++++++ drivers/clk/clk_sandbox.c | 17 +++++++++++++++++ drivers/clk/clk_sandbox_test.c | 10 ++++++++++ include/clk-uclass.h | 8 ++++++++ include/clk.h | 28 ++++++++++++++++++++++++++++ test/dm/clk.c | 22 ++++++++++++++++++++++ 7 files changed, 109 insertions(+)
diff --git a/arch/sandbox/include/asm/clk.h b/arch/sandbox/include/asm/clk.h index c184c4bffc..0294baee27 100644 --- a/arch/sandbox/include/asm/clk.h +++ b/arch/sandbox/include/asm/clk.h @@ -105,6 +105,15 @@ int sandbox_clk_test_get_bulk(struct udevice *dev); * @return: The rate of the clock. */ ulong sandbox_clk_test_get_rate(struct udevice *dev, int id); +/** + * sandbox_clk_test_round_rate - Ask the sandbox clock test device to round a + * clock's rate. + * + * @dev: The sandbox clock test (client) device. + * @id: The test device's clock ID to configure. + * @return: The rounded rate of the clock. + */ +ulong sandbox_clk_test_round_rate(struct udevice *dev, int id, ulong rate); /** * sandbox_clk_test_set_rate - Ask the sandbox clock test device to set a * clock's rate. diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c index 31c5997aea..c16a8b120c 100644 --- a/drivers/clk/clk-uclass.c +++ b/drivers/clk/clk-uclass.c @@ -524,6 +524,21 @@ long long clk_get_parent_rate(struct clk *clk) return pclk->rate; }
+ulong clk_round_rate(struct clk *clk, ulong rate) +{ + const struct clk_ops *ops; + + debug("%s(clk=%p, rate=%lu)\n", __func__, clk, rate); + if (!clk_valid(clk)) + return 0; + + ops = clk_dev_ops(clk->dev); + if (!ops->round_rate) + return -ENOSYS; + + return ops->round_rate(clk, rate); +} + ulong clk_set_rate(struct clk *clk, ulong rate) { const struct clk_ops *ops; diff --git a/drivers/clk/clk_sandbox.c b/drivers/clk/clk_sandbox.c index 768fbb7c52..8361b930df 100644 --- a/drivers/clk/clk_sandbox.c +++ b/drivers/clk/clk_sandbox.c @@ -30,6 +30,22 @@ static ulong sandbox_clk_get_rate(struct clk *clk) return priv->rate[clk->id]; }
+static ulong sandbox_clk_round_rate(struct clk *clk, ulong rate) +{ + struct sandbox_clk_priv *priv = dev_get_priv(clk->dev); + + if (!priv->probed) + return -ENODEV; + + if (clk->id >= SANDBOX_CLK_ID_COUNT) + return -EINVAL; + + if (!rate) + return -EINVAL; + + return rate; +} + static ulong sandbox_clk_set_rate(struct clk *clk, ulong rate) { struct sandbox_clk_priv *priv = dev_get_priv(clk->dev); @@ -103,6 +119,7 @@ static int sandbox_clk_free(struct clk *clk) }
static struct clk_ops sandbox_clk_ops = { + .round_rate = sandbox_clk_round_rate, .get_rate = sandbox_clk_get_rate, .set_rate = sandbox_clk_set_rate, .enable = sandbox_clk_enable, diff --git a/drivers/clk/clk_sandbox_test.c b/drivers/clk/clk_sandbox_test.c index 873383856f..f7b77aa674 100644 --- a/drivers/clk/clk_sandbox_test.c +++ b/drivers/clk/clk_sandbox_test.c @@ -86,6 +86,16 @@ ulong sandbox_clk_test_get_rate(struct udevice *dev, int id) return clk_get_rate(sbct->clkps[id]); }
+ulong sandbox_clk_test_round_rate(struct udevice *dev, int id, ulong rate) +{ + struct sandbox_clk_test *sbct = dev_get_priv(dev); + + if (id < 0 || id >= SANDBOX_CLK_TEST_ID_COUNT) + return -EINVAL; + + return clk_round_rate(sbct->clkps[id], rate); +} + ulong sandbox_clk_test_set_rate(struct udevice *dev, int id, ulong rate) { struct sandbox_clk_test *sbct = dev_get_priv(dev); diff --git a/include/clk-uclass.h b/include/clk-uclass.h index dac42dab36..50e8681b55 100644 --- a/include/clk-uclass.h +++ b/include/clk-uclass.h @@ -61,6 +61,14 @@ struct clk_ops { * @return 0 if OK, or a negative error code. */ int (*rfree)(struct clk *clock); + /** + * round_rate() - Adjust a rate to the exact rate a clock can provide. + * + * @clk: The clock to manipulate. + * @rate: Desidered clock rate in Hz. + * @return rounded rate in Hz, or -ve error code. + */ + ulong (*round_rate)(struct clk *clk, ulong rate); /** * get_rate() - Get current clock rate. * diff --git a/include/clk.h b/include/clk.h index a62e2efa2c..ca6b85fa6f 100644 --- a/include/clk.h +++ b/include/clk.h @@ -366,6 +366,29 @@ struct clk *clk_get_parent(struct clk *clk); */ long long clk_get_parent_rate(struct clk *clk);
+/** + * clk_round_rate() - Adjust a rate to the exact rate a clock can provide + * + * This answers the question "if I were to pass @rate to clk_set_rate(), + * what clock rate would I end up with?" without changing the hardware + * in any way. In other words: + * + * rate = clk_round_rate(clk, r); + * + * and: + * + * rate = clk_set_rate(clk, r); + * + * are equivalent except the former does not modify the clock hardware + * in any way. + * + * @clk: A clock struct that was previously successfully requested by + * clk_request/get_by_*(). + * @rate: desired clock rate in Hz. + * @return rounded rate in Hz, or -ve error code. + */ +ulong clk_round_rate(struct clk *clk, ulong rate); + /** * clk_set_rate() - Set current clock rate. * @@ -482,6 +505,11 @@ static inline long long clk_get_parent_rate(struct clk *clk) return -ENOSYS; }
+static inline ulong clk_round_rate(struct clk *clk, ulong rate) +{ + return -ENOSYS; +} + static inline ulong clk_set_rate(struct clk *clk, ulong rate) { return -ENOSYS; diff --git a/test/dm/clk.c b/test/dm/clk.c index edca3b49f6..21997ed892 100644 --- a/test/dm/clk.c +++ b/test/dm/clk.c @@ -112,6 +112,28 @@ static int dm_test_clk(struct unit_test_state *uts) rate = sandbox_clk_test_set_rate(dev_test, SANDBOX_CLK_TEST_ID_I2C, 0); ut_assert(IS_ERR_VALUE(rate));
+ ut_asserteq(10000, sandbox_clk_test_get_rate(dev_test, + SANDBOX_CLK_TEST_ID_SPI)); + ut_asserteq(20000, sandbox_clk_test_get_rate(dev_test, + SANDBOX_CLK_TEST_ID_I2C)); + + ut_asserteq(5000, sandbox_clk_test_round_rate(dev_test, + SANDBOX_CLK_TEST_ID_SPI, + 5000)); + ut_asserteq(7000, sandbox_clk_test_round_rate(dev_test, + SANDBOX_CLK_TEST_ID_I2C, + 7000)); + + ut_asserteq(10000, sandbox_clk_test_get_rate(dev_test, + SANDBOX_CLK_TEST_ID_SPI)); + ut_asserteq(20000, sandbox_clk_test_get_rate(dev_test, + SANDBOX_CLK_TEST_ID_I2C)); + + rate = sandbox_clk_test_round_rate(dev_test, SANDBOX_CLK_TEST_ID_SPI, 0); + ut_assert(IS_ERR_VALUE(rate)); + rate = sandbox_clk_test_round_rate(dev_test, SANDBOX_CLK_TEST_ID_I2C, 0); + ut_assert(IS_ERR_VALUE(rate)); + ut_asserteq(10000, sandbox_clk_test_get_rate(dev_test, SANDBOX_CLK_TEST_ID_SPI)); ut_asserteq(20000, sandbox_clk_test_get_rate(dev_test,