[PATCH linux dev-4.17] clk: aspeed: Support HPLL strapping on ast2400

[Cédric Le Goater]

On 06/21/2018 09:23 AM, Cédric Le Goater wrote:
> On 06/21/2018 08:57 AM, Joel Stanley wrote:
>> The HPLL can be configured through a register (SCU24), however most
>> some platforms chose to configure it through the strapping settings and
>> do not use the register. This was not noticed as the logic for bit 18 in
>> SCU24 was confused: set means programmed, but the driver read it as set
>> means strapped.
>>
>> This gives us the correct HPLL value on Palmetto systems, from which
>> most of the peripheral clocks are generated.
>>
>> Signed-off-by: Joel Stanley <joel at jms.id.au>
>> ---
>>  drivers/clk/clk-aspeed.c | 22 +++++++++++++++++++---
>>  1 file changed, 19 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
>> index c17032bc853a..c4770cbb6f32 100644
>> --- a/drivers/clk/clk-aspeed.c
>> +++ b/drivers/clk/clk-aspeed.c
>> @@ -24,7 +24,7 @@
>>  #define ASPEED_MPLL_PARAM	0x20
>>  #define ASPEED_HPLL_PARAM	0x24
>>  #define  AST2500_HPLL_BYPASS_EN	BIT(20)
>> -#define  AST2400_HPLL_STRAPPED	BIT(18)
>> +#define  AST2400_HPLL_PROGRAMMED BIT(18)
>>  #define  AST2400_HPLL_BYPASS_EN	BIT(17)
>>  #define ASPEED_MISC_CTRL	0x2c
>>  #define  UART_DIV13_EN		BIT(12)
>> @@ -586,8 +586,24 @@ static void __init aspeed_ast2400_cc(struct regmap *map)
>>  	 * and we assume that it is enabled
>>  	 */
>>  	regmap_read(map, ASPEED_HPLL_PARAM, &val);
>> -	WARN(val & AST2400_HPLL_STRAPPED, "hpll is strapped not configured");
>> -	aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2400_calc_pll("hpll", val);
>> +	if (val & AST2400_HPLL_PROGRAMMED) {
>> +		/* hpll is configured by the strap register */
>> +		aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2400_calc_pll("hpll", val);
>> +	} else {
>> +		/* hpll is configured by the strap register */
>> +		regmap_read(map, ASPEED_STRAP, &val);
>> +		val = (val >> 8) & 0x3;
>> +		if (val == 0x00)
>> +			freq = 384000000;
>> +		else if (val == 0x01)
>> +			freq = 360000000;
>> +		else if (val == 0x02)
>> +			freq = 336000000;
>> +		else if (val == 0x03)
>> +			freq = 408000000;
>> +		aspeed_clk_data->hws[ASPEED_CLK_HPLL] =
> 
> we should try to cover the clkin 25MHz case also. The frequencies are : 
> 
> 	400Mhz 375Mhz 350Mhz 425Mhz
> 
>> +			clk_hw_register_fixed_rate(NULL, "hpll", "clkin", 0, freq);
>> +	}
>>  
>>  	/*
>>  	 * Strap bits 11:10 define the CPU/AHB clock frequency ratio (aka HCLK)
>>
> 
> On a palmetto system :
> 
> 	SCU[70] 0x120CE416 /* 408 MHz */

oups. bit 9:8 are set to 0x0 so that's 384Mhz. All is fine.

Thanks,

C.