linux-kernel - Re: [PATCH v2 02/10] clk: sunxi: Add support for multiple parents to gates

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Date:	Mon, 18 May 2015 11:11:34 +0200
From:	Jens Kuske <jenskuske@...il.com>
To:	Maxime Ripard <maxime.ripard@...e-electrons.com>
CC:	Emilio López <emilio@...pez.com.ar>,
	Mike Turquette <mturquette@...aro.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Rob Herring <robh+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
	Vishnu Patekar <vishnupatekar0510@...il.com>,
	Hans de Goede <hdegoede@...hat.com>,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v2 02/10] clk: sunxi: Add support for multiple parents
 to gates

Hi,

On 05/17/15 14:50, Maxime Ripard wrote:
> Hi Jens,
> 
> On Fri, May 15, 2015 at 06:38:52PM +0200, Jens Kuske wrote:
>> Some newer sunxi SoCs (A83T, H3) don't have individual registers for
>> AHB1, APB1 and APB2 gates anymore, but one big bus gates area where each
>> gate can have a different parent.
>>
>> The current clock driver sets the same parent for all gates in a group.
>> This commit adds a new parents field to the gates_data structure, which
>> allows us to specify an array of parent indices for every single gate.
>>
>> Signed-off-by: Jens Kuske <jenskuske@...il.com>
>> ---
>>  drivers/clk/sunxi/clk-sunxi.c | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
>> index 9a82f17..17cba4d 100644
>> --- a/drivers/clk/sunxi/clk-sunxi.c
>> +++ b/drivers/clk/sunxi/clk-sunxi.c
>> @@ -898,6 +898,8 @@ static void __init sunxi_divider_clk_setup(struct device_node *node,
>>  
>>  struct gates_data {
>>  	DECLARE_BITMAP(mask, SUNXI_GATES_MAX_SIZE);
>> +	/* If used, ARRAY_SIZE(parents) has to be >= bitmap_weight(mask) */
>> +	const u8 *parents;
>>  };
>>  
>>  static const struct gates_data sun4i_axi_gates_data __initconst = {
>> @@ -1000,16 +1002,21 @@ static void __init sunxi_gates_clk_setup(struct device_node *node,
>>  					 struct gates_data *data)
>>  {
>>  	struct clk_onecell_data *clk_data;
>> +	const char *parents[SUNXI_MAX_PARENTS];
>>  	const char *clk_parent;
>>  	const char *clk_name;
>>  	void __iomem *reg;
>> +	int npar = 0;
>>  	int qty;
>>  	int i = 0;
>>  	int j = 0;
>>  
>>  	reg = of_iomap(node, 0);
>>  
>> -	clk_parent = of_clk_get_parent_name(node, 0);
>> +	while (npar < SUNXI_MAX_PARENTS &&
>> +	       (parents[npar] = of_clk_get_parent_name(node, npar)) != NULL)
>> +		npar++;
>> +	clk_parent = parents[0];
>>  
>>  	/* Worst-case size approximation and memory allocation */
>>  	qty = find_last_bit(data->mask, SUNXI_GATES_MAX_SIZE);
>> @@ -1026,6 +1033,9 @@ static void __init sunxi_gates_clk_setup(struct device_node *node,
>>  		of_property_read_string_index(node, "clock-output-names",
>>  					      j, &clk_name);
>>  
>> +		if (data->parents && !WARN_ON(data->parents[j] >= npar))
>> +			clk_parent = parents[data->parents[j]];
>> +
> 
> I'm currently removing that code, so I was more expecting a new
> standalone driver for that clock.

How do you want to replace that code? To me this looks like a good way
to set up all the different gates sunxi has.

Jens
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