[U-Boot,v4,04/13] clk: Extend struct clk to provideinformation regarding clock rate

This commit extends the struct clk to provide information regarding the
clock rate.
As a result the clock tree traversal is performed at most once, and further
reads are using the cached value.

Signed-off-by: Lukasz Majewski <lukma@denx.de>

---

Changes in v4:
- None

Changes in v3: None

 include/clk.h | 2 ++
 1 file changed, 2 insertions(+)

On 5/17/19 12:10 AM, Lukasz Majewski wrote:
> This commit extends the struct clk to provide information regarding the
> clock rate.
> As a result the clock tree traversal is performed at most once, and further
> reads are using the cached value.
> 
> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> 
> ---
> 
> Changes in v4:
> - None
> 
> Changes in v3: None
> 
>  include/clk.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/clk.h b/include/clk.h
> index a909b71f1a..1f2fd15bb5 100644
> --- a/include/clk.h
> +++ b/include/clk.h
> @@ -40,6 +40,7 @@ struct udevice;
>   * other clock APIs to identify which clock signal to operate upon.
>   *
>   * @dev: The device which implements the clock signal.
> + * @rate: The clock rate (in HZ).
>   * @id: The clock signal ID within the provider.
>   * @data: An optional data field for scenarios where a single integer ID is not
>   *	  sufficient. If used, it can be populated through an .of_xlate op and
> @@ -55,6 +56,7 @@ struct udevice;
>   */
>  struct clk {
>  	struct udevice *dev;
> +	unsigned long rate;	/* in HZ */

Can this be unsigned long long ? Think of 3 GHz PLL on arm32 in IDT
Versaclock line of clock synthesisers ; this would overflow right here.

Hi Marek,

> On 5/17/19 12:10 AM, Lukasz Majewski wrote:
> > This commit extends the struct clk to provide information regarding
> > the clock rate.
> > As a result the clock tree traversal is performed at most once, and
> > further reads are using the cached value.
> > 
> > Signed-off-by: Lukasz Majewski <lukma@denx.de>
> > 
> > ---
> > 
> > Changes in v4:
> > - None
> > 
> > Changes in v3: None
> > 
> >  include/clk.h | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/include/clk.h b/include/clk.h
> > index a909b71f1a..1f2fd15bb5 100644
> > --- a/include/clk.h
> > +++ b/include/clk.h
> > @@ -40,6 +40,7 @@ struct udevice;
> >   * other clock APIs to identify which clock signal to operate upon.
> >   *
> >   * @dev: The device which implements the clock signal.
> > + * @rate: The clock rate (in HZ).
> >   * @id: The clock signal ID within the provider.
> >   * @data: An optional data field for scenarios where a single
> > integer ID is not
> >   *	  sufficient. If used, it can be populated through
> > an .of_xlate op and @@ -55,6 +56,7 @@ struct udevice;
> >   */
> >  struct clk {
> >  	struct udevice *dev;
> > +	unsigned long rate;	/* in HZ */  
> 
> Can this be unsigned long long ? Think of 3 GHz PLL on arm32 in IDT
> Versaclock line of clock synthesisers ; this would overflow right
> here.
> 

Thanks for spotting this - I will use unsigned long long instead.


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

On 17/05/19 00:10, Lukasz Majewski wrote:
> This commit extends the struct clk to provide information regarding the
> clock rate.
> As a result the clock tree traversal is performed at most once, and further
> reads are using the cached value.
> 
> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> 
> ---
> 
> Changes in v4:
> - None
> 
> Changes in v3: None
> 
>  include/clk.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/clk.h b/include/clk.h
> index a909b71f1a..1f2fd15bb5 100644
> --- a/include/clk.h
> +++ b/include/clk.h
> @@ -40,6 +40,7 @@ struct udevice;
>   * other clock APIs to identify which clock signal to operate upon.
>   *
>   * @dev: The device which implements the clock signal.
> + * @rate: The clock rate (in HZ).
>   * @id: The clock signal ID within the provider.
>   * @data: An optional data field for scenarios where a single integer ID is not
>   *	  sufficient. If used, it can be populated through an .of_xlate op and
> @@ -55,6 +56,7 @@ struct udevice;
>   */
>  struct clk {
>  	struct udevice *dev;
> +	unsigned long rate;	/* in HZ */
>  	/*
>  	 * Written by of_xlate. In the future, we might add more fields here.
>  	 */
> 


Reviewed-by: Stefano Babic <sbabic@denx.de>

Best regards,
Stefano Babic

> This commit extends the struct clk to provide information regarding the
> clock rate.
> As a result the clock tree traversal is performed at most once, and further
> reads are using the cached value.
> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> Reviewed-by: Stefano Babic <sbabic@denx.de>

Applied to u-boot-imx, master, thanks !

Best regards,
Stefano Babic