Query: clk: Defining new struct clk_foo types

Query: clk: Defining new struct clk_foo types

[Viresh Kumar]

Hi Mike,

I am doing SPEAr SoCs clock port with common clock framework.

Currently there are following type of clk_foo implementations present:
- clk_gate
- clk_divider
- clk_fixed_rate
- clk_mux

I have few more in my SoC:
clk with:
- gate + divider
- gate + fixed_rate
- gate + mux
...

How should i go ahead in my implementation for these?
Should i create SPEAr specific structures or enhance drivers/clk for this?

-- 
viresh

Query: clk: Defining new struct clk_foo types

[Sascha Hauer]

On Thu, Apr 05, 2012 at 12:35:34PM +0530, Viresh Kumar wrote:
> Hi Mike,
> 
> I am doing SPEAr SoCs clock port with common clock framework.
> 
> Currently there are following type of clk_foo implementations present:
> - clk_gate
> - clk_divider
> - clk_fixed_rate
> - clk_mux
> 
> I have few more in my SoC:
> clk with:
> - gate + divider
> - gate + fixed_rate
> - gate + mux
> ...
> 
> How should i go ahead in my implementation for these?
> Should i create SPEAr specific structures or enhance drivers/clk for this?

If you have a gate and a divider then register a gate and a divider.
We don't need clk providers for combination of these, the clock
framework will handle it just fine.

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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Query: clk: Defining new struct clk_foo types

[Viresh Kumar]

On 4/5/2012 3:28 PM, Sascha Hauer wrote:
> If you have a gate and a divider then register a gate and a divider.
> We don't need clk providers for combination of these, the clock
> framework will handle it just fine.

Thanks Sashca, but i didn't get your reply completely.
Lets see if i can understand it with help of an example:

I have uart's clock that can be gated and its rate derived as a divider.
So to define static clock structures, i do following:

DEFINE_CLK_GATE(uart_gate_clk, "uart_parent", &uart_parent_clk,	0,
	0xd0000000, 5, 0, NULL);
DEFINE_CLK_DIVIDER(uart_divider_clk, "uart_parent", &uart_parent_clk,
	0, 0xd0000080, 4, 2, 0, NULL);

You are suggesting this?

If yes, I don't know how it will work. How will clk get work
with dev_id: "uart0". Which one will it pick?

Confused. :(

-- 
viresh

Query: clk: Defining new struct clk_foo types

[Sascha Hauer]

On Thu, Apr 05, 2012 at 03:43:49PM +0530, Viresh Kumar wrote:
> On 4/5/2012 3:28 PM, Sascha Hauer wrote:
> > If you have a gate and a divider then register a gate and a divider.
> > We don't need clk providers for combination of these, the clock
> > framework will handle it just fine.
> 
> Thanks Sashca, but i didn't get your reply completely.
> Lets see if i can understand it with help of an example:
> 
> I have uart's clock that can be gated and its rate derived as a divider.
> So to define static clock structures, i do following:
> 
> DEFINE_CLK_GATE(uart_gate_clk, "uart_parent", &uart_parent_clk,	0,
> 	0xd0000000, 5, 0, NULL);
> DEFINE_CLK_DIVIDER(uart_divider_clk, "uart_parent", &uart_parent_clk,
> 	0, 0xd0000080, 4, 2, 0, NULL);
> 
> You are suggesting this?

No, more like this:

DEFINE_CLK_DIVIDER(uart_divider_clk, "uart_parent", &uart_parent_clk,
       0, 0xd0000080, 4, 2, 0, NULL);
DEFINE_CLK_GATE(uart_gate_clk, "uart_divider_clk", &uart_divider_clk,
	CLK_SET_RATE_PARENT, 0xd0000000, 5, 0, NULL);

So the divider is the parent of the gate and a set_rate call to the gate
will propagate up to the divider.
You could make the gate the parent of the divider if that's how your
hardware really is built, but for the software it makes no difference in
this case.

Besides, I don't  recommend using the DEFINE_CLK_* macros. You should
really consider using clk_register_* instead.

Grmpf. These DEFINE_CLK_* macros are so omnipresent and huge in
clk-private.h that people *must* think they are the way to go.

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Query: clk: Defining new struct clk_foo types

[Viresh Kumar]

On 4/5/2012 4:00 PM, Sascha Hauer wrote:
> Besides, I don't  recommend using the DEFINE_CLK_* macros. You should
> really consider using clk_register_* instead.

Can you point me to some users of this clock framework, with such
runtime stuff? That would be really helpful.

-- 
viresh

Query: clk: Defining new struct clk_foo types

[Sascha Hauer]

On Thu, Apr 05, 2012 at 04:10:40PM +0530, Viresh Kumar wrote:
> On 4/5/2012 4:00 PM, Sascha Hauer wrote:
> > Besides, I don't  recommend using the DEFINE_CLK_* macros. You should
> > really consider using clk_register_* instead.
> 
> Can you point me to some users of this clock framework, with such
> runtime stuff? That would be really helpful.

See this branch:

git://git.pengutronix.de/git/imx/linux-2.6.git work/v3.4-rc1-imx-clk

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |