[PATCH v2] clk: clk_round_rate() should return 0, not negative numbers, upon error

[Paul Walmsley <pwalmsley@nvidia.com>]

Some clock sources can generate clock rates higher than (2^31)-1 Hz.
Currently, if these rates were returned from clk_round_rate(), they
would be considered errors according to the present function prototype
and return type.

This patch updates the documentation for clk_round_rate() to state
that it should return 0 rather than a negative error code when it
encounters an error.  The common clock framework already works this
way; however, other clock code does not yet align to this.

A future patch will modify the prototype to return unsigned values
from clk_round_rate().

This second version revises the patch description in response to
comments from Russell King.

Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
---
  include/linux/clk.h |    2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/clk.h b/include/linux/clk.h
index 9a6d04524b1a..ffbbb7b2de43 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -228,7 +228,7 @@ void devm_clk_put(struct device *dev, struct clk *clk);
   * @clk: clock source
   * @rate: desired clock rate in Hz
   *
- * Returns rounded clock rate in Hz, or negative errno.
+ * Returns rounded clock rate in Hz, or 0 upon error.
   */
  long clk_round_rate(struct clk *clk, unsigned long rate);