[PATCH] clk: bail out early when rate is already desired one

[PATCH] clk: bail out early when rate is already desired one

[Sascha Hauer]

Return successfully from clk_set_rate() when the rate is already the
desired one. This prevents a failure in clk_set_rate() when the current
clock doesn't have a set_rate hook.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/clk/clk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8b90f30486..ba726c342c 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -169,6 +169,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);
 
+	if (clk_get_rate(clk) == clk_round_rate(clk, rate))
+		return 0;
+
 	if (!clk->ops->set_rate)
 		return -ENOSYS;
 
-- 
2.29.2


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Re: [PATCH] clk: bail out early when rate is already desired one

[Ahmad Fatoum]

On 07.06.21 16:12, Sascha Hauer wrote:
> Return successfully from clk_set_rate() when the rate is already the
> desired one. This prevents a failure in clk_set_rate() when the current
> clock doesn't have a set_rate hook.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/clk/clk.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 8b90f30486..ba726c342c 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -169,6 +169,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
>  	if (IS_ERR(clk))
>  		return PTR_ERR(clk);
>  
> +	if (clk_get_rate(clk) == clk_round_rate(clk, rate))
> +		return 0;
> +
>  	if (!clk->ops->set_rate)
>  		return -ENOSYS;


This means we can drop 459bf1fd31da ("ARM: clk: rk3188: don't set same
clk rate twice"), right?


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Re: [PATCH] clk: bail out early when rate is already desired one

[Sascha Hauer]

On Mon, Jun 07, 2021 at 05:46:12PM +0200, Ahmad Fatoum wrote:
> 
> 
> On 07.06.21 16:12, Sascha Hauer wrote:
> > Return successfully from clk_set_rate() when the rate is already the
> > desired one. This prevents a failure in clk_set_rate() when the current
> > clock doesn't have a set_rate hook.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > ---
> >  drivers/clk/clk.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index 8b90f30486..ba726c342c 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -169,6 +169,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
> >  	if (IS_ERR(clk))
> >  		return PTR_ERR(clk);
> >  
> > +	if (clk_get_rate(clk) == clk_round_rate(clk, rate))
> > +		return 0;
> > +
> >  	if (!clk->ops->set_rate)
> >  		return -ENOSYS;
> 
> 
> This means we can drop 459bf1fd31da ("ARM: clk: rk3188: don't set same
> clk rate twice"), right?

Indeed, yes. This part was lost with "clk: rockchip: Update to current
Linux" anyway, so nothing to do here.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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