Re: [RFC PATCH v1 3/6] clk: rockchip: rk3399: add ddrc clock support

[hl <hl@rock-chips.com>]

Hi Heiko,

On 2016年06月03日 20:56, Heiko Stübner wrote:
> Am Freitag, 3. Juni 2016, 17:55:16 schrieb Lin Huang:
>> add ddrc clock setting, so we can do ddr frequency
>> scaling on rk3399 platform in future.
>>
>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>> ---
>> Changes in v1:
>> - remove ddrc source CLK_IGNORE_UNUSED flag, Suggestion by Doug
>> - move clk_ddrc and clk_ddrc_dpll_src to critical, Suggestion by Doug
>>
>>   drivers/clk/rockchip/clk-rk3399.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/drivers/clk/rockchip/clk-rk3399.c
>> b/drivers/clk/rockchip/clk-rk3399.c index f1d8e44..29afb88 100644
>> --- a/drivers/clk/rockchip/clk-rk3399.c
>> +++ b/drivers/clk/rockchip/clk-rk3399.c
> [...]
>
>> @@ -1377,6 +1381,18 @@ static struct rockchip_clk_branch
>> rk3399_clk_branches[] __initdata = { COMPOSITE_NOMUX(0, "clk_test",
>> "clk_test_pre", CLK_IGNORE_UNUSED, RK3368_CLKSEL_CON(58), 0, 5, DFLAGS,
>>   			RK3368_CLKGATE_CON(13), 11, GFLAGS),
>> +
>> +	/* ddrc */
>> +	GATE(0, "clk_ddrc_lpll_src", "lpll", 0, RK3399_CLKGATE_CON(3),
>> +	     0, GFLAGS),
>> +	GATE(0, "clk_ddrc_bpll_src", "bpll", 0, RK3399_CLKGATE_CON(3),
>> +	     1, GFLAGS),
>> +	GATE(0, "clk_ddrc_dpll_src", "dpll", 0, RK3399_CLKGATE_CON(3),
>> +	     2, GFLAGS),
>> +	GATE(0, "clk_ddrc_gpll_src", "gpll", 0, RK3399_CLKGATE_CON(3),
>> +	     3, GFLAGS),
>> +	COMPOSITE_DDRC(SCLK_DDRCLK, "clk_ddrc", mux_ddrclk_p, 0,
>> +		       RK3399_CLKSEL_CON(6), 4, 2, MFLAGS, 0, 3, DFLAGS),
>>   };
> as said in the other patch, just make this a regular COMPOSITE_NOGATE with
> CLK_DIVIDER_READ_ONLY | CLK_MUX_READ_ONLY until that interface to the ATF
> exists and is approved.
>
> That way you can still read back the clock rate without anything changing the
> clock-rate, but we don't need to add duplicate code for it.
>
>
>>   static struct rockchip_clk_branch rk3399_clk_pmu_branches[] __initdata = {
>> @@ -1487,6 +1503,10 @@ static const char *const rk3399_cru_critical_clocks[]
>> __initconst = { "gpll_hclk_perilp1_src",
>>   	"gpll_aclk_perilp0_src",
>>   	"gpll_aclk_perihp_src",
>> +
>> +	/* ddrc */
>> +	"clk_ddrc_dpll_src",
> Why does your clk_ddrc_dpll_src need a separate critical entry. Any code
> changing the clk_ddrc parent should make sure the new parent is enabled. (The
> clock-framework of course does this already).
     Okay, thank you.
>
>> +	"clk_ddrc",
>>   };
>>
>>   static const char *const rk3399_pmucru_critical_clocks[] __initconst = {
>
> Heiko
>
>
>
>

-- 
Lin Huang