[PATCH 2/2] [RFC] clk: stm32mp1: Handle SoC speed grade configs

[Marek Vasut]

On 5/13/20 11:12 AM, Patrick DELAUNAY wrote:
> Dear Marek,
> 
>> From: Marek Vasut <marex at denx.de>
>> Sent: mardi 12 mai 2020 19:07
>>
>> There are two speed grades of the STM32MP1, the A/C and D/F, the former can
>> run up to 650 MHz, the later at up to 800 MHz. Allow specifying PLL config for
>> both in the DT, so that it is possible to cater for boards which can be populated
>> with either SoC.
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> Cc: Patrick Delaunay <patrick.delaunay at st.com>
>> Cc: Patrice Chotard <patrice.chotard at st.com>
>> ---
>>  drivers/clk/clk_stm32mp1.c | 30 ++++++++++++++++++++++++++----
>>  1 file changed, 26 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/clk/clk_stm32mp1.c b/drivers/clk/clk_stm32mp1.c index
>> 50df8425bf..cecc06638e 100644
>> --- a/drivers/clk/clk_stm32mp1.c
>> +++ b/drivers/clk/clk_stm32mp1.c
>> @@ -4,6 +4,7 @@
>>   */
>>
>>  #include <common.h>
>> +#include <asm/arch/sys_proto.h>
>>  #include <clk-uclass.h>
>>  #include <div64.h>
>>  #include <dm.h>
>> @@ -1464,6 +1465,12 @@ static void pll_csg(struct stm32mp1_clk_priv *priv, int
>> pll_id, u32 *csg)
>>  	setbits_le32(priv->base + pll[pll_id].pllxcr, RCC_PLLNCR_SSCG_CTRL);
>> }
>>
>> +static __maybe_unused int stm32mp1_is_df(void) {
>> +	/* ID bit 7 is set on 15x{D,F}xx and not on 15x{A,C}xx */
>> +	return get_cpu_type() & BIT(7);
>> +}
>> +
>>  static  __maybe_unused int pll_set_rate(struct udevice *dev,
>>  					int pll_id,
>>  					int div_id,
>> @@ -1491,8 +1498,13 @@ static  __maybe_unused int pll_set_rate(struct
>> udevice *dev,
>>
>>  	ret = ofnode_read_u32_array(plloff, "cfg",
>>  				    pllcfg, PLLCFG_NB);
>> -	if (ret < 0)
>> -		return -FDT_ERR_NOTFOUND;
>> +	if (ret < 0) {
>> +		ret = ofnode_read_u32_array(plloff,
>> +				stm32mp1_is_df() ? "cfg-df" : "cfg-ac",
>> +				pllcfg, PLLCFG_NB);
>> +		if (ret < 0)
>> +			return -FDT_ERR_NOTFOUND;
>> +	}
>>
>>  	fck_ref = pll_get_fref_ck(priv, pll_id);
>>
>> @@ -1687,8 +1699,13 @@ static int stm32mp1_clktree(struct udevice *dev)
>>  		ret = ofnode_read_u32_array(plloff[i], "cfg",
>>  					    pllcfg[i], PLLCFG_NB);
>>  		if (ret < 0) {
>> -			debug("field cfg invalid: error %d\n", ret);
>> -			return -FDT_ERR_NOTFOUND;
>> +			ret = ofnode_read_u32_array(plloff[i],
>> +					stm32mp1_is_df() ? "cfg-df" : "cfg-ac",
>> +					pllcfg[i], PLLCFG_NB);
>> +			if (ret < 0) {
>> +				debug("field cfg invalid: error %d\n", ret);
>> +				return -FDT_ERR_NOTFOUND;
>> +			}
>>  		}
>>  	}
>>
>> @@ -1783,6 +1800,11 @@ static int stm32mp1_clktree(struct udevice *dev)
>>  			continue;
>>
>>  		fracv = ofnode_read_u32_default(plloff[i], "frac", 0);
>> +		if (!fracv) {
>> +			fracv = ofnode_read_u32_default(plloff[i],
>> +					stm32mp1_is_df() ? "frac-df" : "frac-ac",
>> +					0);
>> +		}
>>  		pll_config(priv, i, pllcfg[i], fracv);
>>  		ret = ofnode_read_u32_array(plloff[i], "csg", csg, PLLCSG_NB);
>>  		if (!ret) {
>> --
>> 2.25.1
> 
> The 2 speed grade will be supported with OPP information and HW support,present in kernel device tree (upstream in progress) 
> 
> I port this patch in U-Boot with:
> http://patchwork.ozlabs.org/project/uboot/patch/20200421171123.2.Id3620aec4deb419f1c1a5876b865556e86d3aba1@changeid/
> 
> 
> Please check the full serie
> stm32mp1: use OPP information for PLL1 settings in SPL
> http://patchwork.ozlabs.org/project/uboot/list/?series=171767
> 
> PLL1 settings are now computed in SPL and no more read from DT.

That's even better, nice, thanks !

btw. does the D/F 800 MHz always set BIT(7) in the CPU ID , while the
A/C 650 MHz part never does ? Maybe you can use that to discern the
speed grades instead of listing all the parts ...

-- 
Best regards,
Marek Vasut