Subject: [PATCH v2 1/7] clk: sunxi: Add support for AXI, AHB, APB0 and APB1 gates

From: [email-masked] (Gregory CLEMENT)
Date: Thu, 04 Apr 2013 22:45:24 +0200

On 04/04/2013 04:46 AM, Mike Turquette wrote:
> Quoting Emilio L??pez (2013-04-03 18:19:22)
>> Hi Mike,
>>
>> El 03/04/13 18:48, Mike Turquette escribi??:
>>> Quoting Emilio L??pez (2013-03-27 14:20:37)
>>>> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
>>>> index d528a24..244de90 100644
>>>> --- a/drivers/clk/sunxi/clk-sunxi.c
>>>> +++ b/drivers/clk/sunxi/clk-sunxi.c
>>>> @@ -302,6 +302,82 @@ static void __init sunxi_divider_clk_setup(struct device_node *node,
>>>>  }
>>>>  
>>>>  
>>>> +
>>>
>>> A lot of white space between these functions.
>>
>> All of the function blocks are separated with three spaces on the file;
>> I thought it looked more readable that way, but I don't have any strong
>> opinion on separation. Is there any standard for this used on the kernel?
>>
>> In any case, and to keep consistency, can we handle this on a follow-up
>> patch?
>>
> 
> If it's consistent throughout the file then go ahead and keep it.
> 
>>>> +/**
>>>> + * sunxi_gates_clk_setup() - Setup function for leaf gates on clocks
>>>> + */
>>>> +
>>>> +#define SUNXI_GATES_MAX_SIZE   64
>>>> +
>>>> +struct gates_data {
>>>> +       DECLARE_BITMAP(mask, SUNXI_GATES_MAX_SIZE);
>>>> +};
>>>> +
>>>> +static const __initconst struct gates_data axi_gates_data = {
>>>> +       .mask = {1},
>>>> +};
>>>> +
>>>> +static const __initconst struct gates_data ahb_gates_data = {
>>>> +       .mask = {0x7F77FFF, 0x14FB3F},
>>>> +};
>>>> +
>>>> +static const __initconst struct gates_data apb0_gates_data = {
>>>> +       .mask = {0x4EF},
>>>> +};
>>>> +
>>>> +static const __initconst struct gates_data apb1_gates_data = {
>>>> +       .mask = {0xFF00F7},
>>>> +};
>>>> +
>>>> +static void __init sunxi_gates_clk_setup(struct device_node *node,
>>>> +                                        struct gates_data *data)
>>>> +{
>>>> +       struct clk_onecell_data *clk_data;
>>>> +       const char *clk_parent;
>>>> +       const char *clk_name;
>>>> +       void *reg;
>>>> +       int qty;
>>>> +       int i = 0;
>>>> +       int j = 0;
>>>> +       int ignore;
>>>> +
>>>> +       reg = of_iomap(node, 0);
>>>> +
>>>> +       clk_parent = of_clk_get_parent_name(node, 0);
>>>> +
>>>> +       /* Worst-case size approximation and memory allocation */
>>>> +       qty = find_last_bit(data->mask, SUNXI_GATES_MAX_SIZE);
>>>> +       clk_data = kmalloc(sizeof(struct clk_onecell_data), GFP_KERNEL);
>>>> +       if (!clk_data)
>>>> +               return;
>>>> +       clk_data->clks = kzalloc((qty+1) * sizeof(struct clk *), GFP_KERNEL);
>>>> +       if (!clk_data->clks) {
>>>> +               kfree(clk_data);
>>>> +               return;
>>>> +       }
>>>> +
>>>> +       for_each_set_bit(i, data->mask, SUNXI_GATES_MAX_SIZE) {
>>>> +               of_property_read_string_index(node, "clock-output-names",
>>>> +                                             j, &clk_name);
>>>> +
>>>> +               /* No driver claims this clock, but it should remain gated */
>>>
>>> Should the comment read, "ungated" instead of "gated"?
>>
>> Indeed, good catch. Do you want me to resend the series, or can you
>> amend this when picking the patches?
>>
> 
> I can amend it, but I don't like to get into the habit of doing that too
> often.
> 
> I'll wait on Gregory's response on the of_clk_init stuff before I do so.
> 
> Regards,
> Mike
> 
>>>> +               ignore = !strcmp("ahb_sdram", clk_name) ? CLK_IGNORE_UNUSED : 0;
>>>> +
>>>> +               clk_data->clks[i] = clk_register_gate(NULL, clk_name,
>>>> +                                                     clk_parent, ignore,
>>>> +                                                     reg + 4 * (i/32), i % 32,
>>>> +                                                     0, &clk_lock);
>>>> +               WARN_ON(IS_ERR(clk_data->clks[i]));
>>>> +
>>>> +               j++;
>>>> +       }
>>>> +
>>>> +       /* Adjust to the real max */
>>>> +       clk_data->clk_num = i;
>>>> +
>>>> +       of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
>>>> +}
>>>> +
>>>>  /* Matches for of_clk_init */
>>>>  static const __initconst struct of_device_id clk_match[] = {
>>>>         {.compatible = "fixed-clock", .data = of_fixed_clk_setup,},
>>>> @@ -331,6 +407,15 @@ static const __initconst struct of_device_id clk_mux_match[] = {
>>>>         {}
>>>>  };
>>>>  
>>>> +/* Matches for gate clocks */
>>>> +static const __initconst struct of_device_id clk_gates_match[] = {
>>>> +       {.compatible = "allwinner,sun4i-axi-gates-clk", .data = &axi_gates_data,},
>>>> +       {.compatible = "allwinner,sun4i-ahb-gates-clk", .data = &ahb_gates_data,},
>>>> +       {.compatible = "allwinner,sun4i-apb0-gates-clk", .data = &apb0_gates_data,},
>>>> +       {.compatible = "allwinner,sun4i-apb1-gates-clk", .data = &apb1_gates_data,},
>>>> +       {}
>>>> +};
>>>> +
>>>>  static void __init of_sunxi_table_clock_setup(const struct of_device_id *clk_match,
>>>>                                               void *function)
>>>>  {
>>>> @@ -359,4 +444,7 @@ void __init sunxi_init_clocks(void)
>>>>  
>>>>         /* Register mux clocks */
>>>>         of_sunxi_table_clock_setup(clk_mux_match, sunxi_mux_clk_setup);
>>>> +
>>>> +       /* Register gate clocks */
>>>> +       of_sunxi_table_clock_setup(clk_gates_match, sunxi_gates_clk_setup);
>>>
>>> I'm still a device tree noob, so this may be a dumb question.  Can the
>>> above be converted to of_clk_init?
>>
>> As far as I know, you can't, because of_clk_init doesn't allow for
>> custom data to be passed to the functions. If we were to use of_clk_init
>> we would need one function per clock, and it would be mostly duplicated
>> code / wrappers. I've added Gregory on Cc, please correct me if this is
>> not the case.

I confirm that the current implementation of of_clk_init only take setup
functions. That was also the reason why we didn't use it in mvebu/clk-core.c
for example.

Maybe it should be a good improvement to allow of_clk_init to receive
a function _and_ data for a given node. Something like that;

typedef void (*of_clk_init_cb_t)(struct device_node *, void *data);
struct clk_of_setup {
of_clk_init_cb_t clk_init_cb;
void* data;
}

void __init of_clk_init(const struct of_device_id *matches)
{
	struct device_node *np;

	if (!matches)
		matches = __clk_of_table;

	for_each_matching_node(np, matches) {
		const struct of_device_id *match = of_match_node(matches, np);
		match->clk_init_cb(np, match->data);
	}
}

I have just writen this code in this email I didn't even try to compile this code.
This was just a rough idea which could be use as a base for future patch for 3.11.
With a good coccinelle script it should be not too complicated.

But about this current patch, I am fine with it, and you can add my
Reviewed-by: Gregory CLEMENT <[email-masked]>

>> Thanks for the review,
>> Emilio

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com