Subject: [PATCH] clk: socfpga: Map the clk manager base address in the clock driver

From: [email-masked] (Dinh Nguyen)
Date: Mon, 09 Dec 2013 17:04:41 -0600

On 12/9/13 3:31 PM, Arnd Bergmann wrote:
> On Monday 09 December 2013, dinguyen at altera.com wrote:
>> From: Dinh Nguyen <[email-masked]>
>>
>> The clk manager's base address was being mapped in SOCFPGA's arch code and
>> being extern'ed out to the clock driver. This method is not correct, and the
>> arch code was not really doing anything with that clk manager anyways.
>>
>> This patch moves the mapping of the clk manager's base address in the clock
>> driver itself.
>>
>> Signed-off-by: Dinh Nguyen <[email-masked]>
> Ok, thanks for doing this cleanup. A few comments for further simplification:
>
>> -extern void __iomem *clk_mgr_base_addr;
>> -
>>  struct socfpga_clk {
>>  	struct clk_gate hw;
>>  	char *parent_name;
>>  	char *clk_name;
>> +	void __iomem *clk_mgr_base_addr;
>>  	u32 fixed_div;
>>  	void __iomem *div_reg;
>>  	u32 width;	/* only valid if div_reg != 0 */
>
> I think there is no need to make this a per-clock field, it's fine to
> have a 'static' variable in the place of the 'extern' declaration you have now.
Ok.
>
>> @@ -129,7 +130,11 @@ static __init struct clk *socfpga_clk_init(struct device_node *node,
>>  	if (WARN_ON(!socfpga_clk))
>>  		return NULL;
>>  
>> -	socfpga_clk->hw.reg = clk_mgr_base_addr + reg;
>> +	/* Map the clk manager register */
>> +	clk_mgr_np = of_find_compatible_node(NULL, NULL, "altr,clk-mgr");
>> +	socfpga_clk->hw.reg = of_iomap(clk_mgr_np, 0);
>> +	BUG_ON(!socfpga_clk->hw.reg);
>> +	socfpga_clk->hw.reg += reg;
>>  
>>  	rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
>>  	if (rc)
> Instead of mapping it every time, I suggest something along the lines of
> this patch:
>
> diff --git a/drivers/clk/socfpga/clk.c b/drivers/clk/socfpga/clk.c
> index 81dd31a..1a14742 100644
> --- a/drivers/clk/socfpga/clk.c
> +++ b/drivers/clk/socfpga/clk.c
> @@ -55,7 +55,7 @@
>  #define div_mask(width)	((1 << (width)) - 1)
>  #define streq(a, b) (strcmp((a), (b)) == 0)
>  
> -extern void __iomem *clk_mgr_base_addr;
> +static void __iomem *clk_mgr_base_addr;
>  
>  struct socfpga_clk {
>  	struct clk_gate hw;
> @@ -322,19 +322,30 @@ static void __init socfpga_pll_init(struct device_node *node)
>  {
>  	socfpga_clk_init(node, &clk_pll_ops);
>  }
> -CLK_OF_DECLARE(socfpga_pll, "altr,socfpga-pll-clock", socfpga_pll_init);
>  
>  static void __init socfpga_periph_init(struct device_node *node)
>  {
>  	socfpga_clk_init(node, &periclk_ops);
>  }
> -CLK_OF_DECLARE(socfpga_periph, "altr,socfpga-perip-clk", socfpga_periph_init);
>  
>  static void __init socfpga_gate_init(struct device_node *node)
>  {
>  	socfpga_gate_clk_init(node, &gateclk_ops);
>  }
> -CLK_OF_DECLARE(socfpga_gate, "altr,socfpga-gate-clk", socfpga_gate_init);
> +
> +static struct of_device_id socfpga_child_clocks[] = {
> +	{ "altr,socfpga-pll-clock", socfpga_pll_init },
> +	{ "altr,socfpga-perip-clk", socfpga_periph_init },
> +	{ "altr,socfpga-gate-clk", socfpga_gate_init },
> +	{},
> +};
> +
> +static void __init socfpga_pll_init(struct device_node *node)
> +{
> +	clk_mgr_base_addr = of_iomap(node, 0);
> +	of_clk_init(socfpga_child_clocks);
> +}
> +CLK_OF_DECLARE(socfpga_mgr, "altr,clk-mgr", socfpga_clkmgr_init);
>  
>  void __init socfpga_init_clocks(void)
>  {
>
>
> On a related note, I'd also like to see socfpga_init_clocks() disappear. It should
> be trivial to just add the "mpuclk" into the DT as a separate
> compatible = "fixed-factor-clock" node.
Please see:

http://lists.infradead.org/pipermail/linux-arm-kernel/2013-December/216664.html

Thanks for the review.

Dinh
> 	Arnd