[PATCH AUTOSEL 5.4 050/134] clk: clk-gpio: propagate rate change to parent

Sasha Levin
2019-12-11T16:05:59Z

From: Michael Hennerich <michael.hennerich@analog.com>

[ Upstream commit fc59462c5ce60da119568fac325c92fc6b7c6175 ]

For an external clock source, which is gated via a GPIO, the
rate change should typically be propagated to the parent clock.

The situation where we are requiring this propagation, is when an
external clock is connected to override an internal clock (which typically
has a fixed rate). The external clock can have a different rate than the
internal one, and may also be variable, thus requiring the rate
propagation.

This rate change wasn't propagated until now, and it's unclear about cases
where this shouldn't be propagated. Thus, it's unclear whether this is
fixing a bug, or extending the current driver behavior. Also, it's unsure
about whether this may break any existing setups; in the case that it does,
a device-tree property may be added to disable this flag.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lkml.kernel.org/r/20191108071718.17985-1-alexandru.ardelean@analog.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/clk/clk-gpio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
index 9d930edd65162..13304cf5f2a8f 100644
--- a/drivers/clk/clk-gpio.c
+++ b/drivers/clk/clk-gpio.c
@@ -280,7 +280,7 @@ static int gpio_clk_driver_probe(struct platform_device *pdev)
else
clk = clk_register_gpio_gate(&pdev->dev, node->name,
parent_names ? parent_names[0] : NULL, gpiod,
- 0);
+ CLK_SET_RATE_PARENT);
if (IS_ERR(clk))
return PTR_ERR(clk);

--
2.20.1