[PATCHv11 06/49] clk: add support for low level register ops

[Paul Walmsley]

On Thu, 19 Dec 2013, Tero Kristo wrote:

> Low level register ops are needed for providing SoC or IP block specific
> access routines to clock registers. Subsequent patches add support for
> the low level ops for the individual clock drivers.
> 
> Signed-off-by: Tero Kristo <t-kristo at ti.com>

...

> ---
>  drivers/clk/clk.c            |   28 ++++++++++++++++++++++++++++
>  include/linux/clk-provider.h |   13 +++++++++++++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 29281f6..23a742b 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -34,6 +34,34 @@ static HLIST_HEAD(clk_root_list);
>  static HLIST_HEAD(clk_orphan_list);
>  static LIST_HEAD(clk_notifier_list);
>  
> +/**
> + * clk_readl_default - default clock register read support function
> + * @reg: register to read
> + *
> + * Default implementation for reading a clock register.
> + */
> +static u32 clk_readl_default(u32 __iomem *reg)

Why u32 __iomem rather than void *?  Not that this will affect OMAP, but 
will this need to be changed later to support 64-bit addresses?  
__raw_writel() and __raw_readl() are defined with "void __iomem *" as 
their address argument, which will be 64 bits on arm64, correct?

> +{
> +	return readl(reg);
> +}
> +
> +/**
> + * clk_writel_default - default clock register write support function
> + * @val: value to write
> + * @reg: register to write to
> + *
> + * Default implementation for writing a clock register.
> + */
> +static void clk_writel_default(u32 val, u32 __iomem *reg)

Same question as the above.

> +{
> +	writel(val, reg);
> +}
> +
> +struct clk_ll_ops clk_ll_ops_default = {
> +	.clk_readl = clk_readl_default,
> +	.clk_writel = clk_writel_default
> +};
> +
>  /***           locking             ***/
>  static void clk_prepare_lock(void)
>  {
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 27a9765..cc5bee0 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -199,6 +199,24 @@ struct clk_hw {
>  	const struct clk_init_data *init;
>  };
>  
> +/**
> + * struct clk_ll_ops - low-level register access ops for a clock
> + *
> + * @clk_readl: pointer to register read function

Please remove the blank line above as mentioned before.

> + * @clk_writel: pointer to register write function
> + *
> + * Low-level register access ops are generally used by the basic clock types
> + * (clk-gate, clk-mux, clk-divider etc.) to provide support for various
> + * low-level hardware interfaces (direct MMIO, regmap etc.), but can also be
> + * used by other hardware-specific clock drivers if needed.
> + */
> +struct clk_ll_ops {
> +	u32	(*clk_readl)(u32 __iomem *reg);
> +	void	(*clk_writel)(u32 val, u32 __iomem *reg);
> +};
> +
> +extern struct clk_ll_ops clk_ll_ops_default;
> +
>  /*
>   * DOC: Basic clock implementations common to many platforms
>   *
> -- 
> 1.7.9.5
> 


- Paul