On Wed, Jun 18, 2014 at 6:04 PM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Jun 17, 2014 at 10:52:46PM +0800, Chen-Yu Tsai wrote:
>> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
>> ---
>> Documentation/devicetree/bindings/clock/sunxi.txt | 1 +
>> drivers/clk/sunxi/clk-sunxi.c | 44 +++++++++++++++++++++++
>> 2 files changed, 45 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
>> index b9ec668..7b2ba41 100644
>> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
>> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
>> @@ -40,6 +40,7 @@ Required properties:
>> "allwinner,sun6i-a31-apb2-div-clk" - for the APB2 gates on A31
>> "allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31
>> "allwinner,sun4i-a10-mod0-clk" - for the module 0 family of clocks
>> + "allwinner,sun6i-a31-mbus-clk" - for the MBUS clocks on A31 / A23
>> "allwinner,sun7i-a20-out-clk" - for the external output clocks
>> "allwinner,sun7i-a20-gmac-clk" - for the GMAC clock module on A20/A31
>> "allwinner,sun4i-a10-usb-clk" - for usb gates + resets on A10 / A20
>> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
>> index eca3c6e..a086b5b 100644
>> --- a/drivers/clk/sunxi/clk-sunxi.c
>> +++ b/drivers/clk/sunxi/clk-sunxi.c
>> @@ -307,6 +307,37 @@ static void sun4i_get_mod0_factors(u32 *freq, u32 parent_rate,
>>
>>
>> /**
>> + * sun6i_a31_get_mbus_factors() - calculates m factor for MBUS clocks
>> + * MBUS rate is calculated as follows
>> + * rate = parent_rate / (m + 1);
>> + */
>> +
>> +static void sun6i_a31_get_mbus_factors(u32 *freq, u32 parent_rate,
>> + u8 *n, u8 *k, u8 *m, u8 *p)
>> +{
>> + u8 div;
>> +
>> + /* These clocks can only divide, so we will never be able to achieve
>> + * frequencies higher than the parent frequency */
>> + if (*freq > parent_rate)
>> + *freq = parent_rate;
>> +
>> + div = DIV_ROUND_UP(parent_rate, *freq);
>> +
>> + if (div > 8)
>> + div = 8;
>> +
>> + *freq = parent_rate / div;
>> +
>> + /* we were called to round the frequency, we can now return */
>> + if (n == NULL)
>
> s/n/m/ ?
The factors clk driver passes all or none pointers.
But I will change this to avoid the confusion.
>> + return;
>> +
>> + *m = div - 1;
>> +}
>> +
>> +
>> +/**
>> * sun7i_a20_get_out_factors() - calculates m, p factors for CLK_OUT_A/B
>> * CLK_OUT rate is calculated as follows
>> * rate = (parent_rate >> p) / (m + 1);
>> @@ -447,6 +478,11 @@ static struct clk_factors_config sun4i_mod0_config = {
>> .pwidth = 2,
>> };
>>
>> +static struct clk_factors_config sun6i_a31_mbus_config = {
>> + .mshift = 0,
>> + .mwidth = 3,
>
> Actually, the A31 has an extra N factor.
>
> So this mbus clock looks like it's only about the A23, and not the A31
> at all.
I checked original sun6i code and sun6i code found in the A23 SDK.
The original code uses the module 0 clock driver for mbus, so yes
there's an extra N factor. The new code in the A23 SDK does not.
Unfortunately I haven't been able to get my Hummingbird A31 up yet,
so I can't poke around to check it.
ChenYu
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