Subject: [PATCHv10 01/41] clk: add support for platform specific clock I/O wrapper functions

From: [email-masked] (Tero Kristo)
Date: Mon, 16 Dec 2013 10:06:01 +0200

On 12/15/2013 02:48 AM, Mike Turquette wrote:
> Quoting Tero Kristo (2013-11-26 00:05:42)
>> Current clock wrappers assume simple and direct mapped hardware register
>> access. Improve this support by adding functionality for registering
>> platform specific clock I/O wrappers, which can be used to support
>> various features needed like endianess conversions, indexed regmap support,
>> etc. Default I/O wrapper provided also which uses the existing direct
>> I/O mapped behavior.
>>
>> Signed-off-by: Tero Kristo <[email-masked]>
>
> There is a separate discussion on removing regmap for reading omap clk
> registers. I guess this patch is not needed in that case?

Actually, this is still needed, as I need to map the clocks according to 
their parent nodes.

-Tero

>
> Regards,
> Mike
>
>> ---
>>   drivers/clk/clk.c            |   68 ++++++++++++++++++++++++++++++++++++++++++
>>   include/linux/clk-provider.h |   15 +++++-----
>>   2 files changed, 75 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
>> index 2cf2ea6..c331386 100644
>> --- a/drivers/clk/clk.c
>> +++ b/drivers/clk/clk.c
>> @@ -34,6 +34,74 @@ 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)
>> +{
>> +       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)
>> +{
>> +       writel(val, reg);
>> +}
>> +
>> +struct clk_reg_ops clk_reg_ops_default = {
>> +       .clk_readl = clk_readl_default,
>> +       .clk_writel = clk_writel_default
>> +};
>> +
>> +static struct clk_reg_ops *clk_reg_ops = &clk_reg_ops_default;
>> +
>> +/**
>> + * clk_register_reg_ops - register access functions for clock registers
>> + * @ops: register level ops
>> + *
>> + * Registers platform or SoC specific operations for reading / writing
>> + * clock registers.
>> + */
>> +int clk_register_reg_ops(struct clk_reg_ops *ops)
>> +{
>> +       if (!ops)
>> +               return -EINVAL;
>> +       clk_reg_ops = ops;
>> +       return 0;
>> +}
>> +
>> +/**
>> + * clk_readl - read a clock register value from hardware
>> + * @reg: register to read
>> + *
>> + * Uses the registered clk_reg_ops to read a hardware clock register value.
>> + */
>> +u32 clk_readl(u32 __iomem *reg)
>> +{
>> +       return clk_reg_ops->clk_readl(reg);
>> +}
>> +
>> +/**
>> + * clk_writel - write a clock register value to hardware
>> + * @val: value to write
>> + * @reg: register to write
>> + *
>> + * Uses the registered clk_reg_ops to write a hardware clock register value.
>> + */
>> +void clk_writel(u32 val, u32 __iomem *reg)
>> +{
>> +       clk_reg_ops->clk_writel(val, reg);
>> +}
>> +
>>   /***           locking             ***/
>>   static void clk_prepare_lock(void)
>>   {
>> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
>> index 7e59253..16e4df2 100644
>> --- a/include/linux/clk-provider.h
>> +++ b/include/linux/clk-provider.h
>> @@ -512,15 +512,14 @@ static inline const char *of_clk_get_parent_name(struct device_node *np,
>>    * for improved portability across platforms
>>    */
>>
>> -static inline u32 clk_readl(u32 __iomem *reg)
>> -{
>> -       return readl(reg);
>> -}
>> +struct clk_reg_ops {
>> +       u32 (*clk_readl)(u32 __iomem *reg);
>> +       void (*clk_writel)(u32 val, u32 __iomem *reg);
>> +};
>>
>> -static inline void clk_writel(u32 val, u32 __iomem *reg)
>> -{
>> -       writel(val, reg);
>> -}
>> +u32 clk_readl(u32 __iomem *reg);
>> +void clk_writel(u32 val, u32 __iomem *reg);
>> +int clk_register_reg_ops(struct clk_reg_ops *ops);
>>
>>   #endif /* CONFIG_COMMON_CLK */
>>   #endif /* CLK_PROVIDER_H */
>> --
>> 1.7.9.5
>>