[PATCH] clk: qcom: gcc-qcs404: fix initial rate of GPLL3

[PATCH] clk: qcom: gcc-qcs404: fix initial rate of GPLL3

[Gabor Juhos]

The comment before the config of the GPLL3 PLL says that the
PLL should run at 930 MHz. In contrary to this, calculating
the frequency from the current configuration values by using
19.2 MHz as input frequency defined in 'qcs404.dtsi', it gives
921.6 MHz:

  $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x0
  $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
  921600000.00000000000000000000

Set 'alpha_hi' in the configuration to a value used in downstream
kernels [1][2] in order to get the correct output rate:

  $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x70
  $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
  930000000.00000000000000000000

The change is based on static code analysis, compile tested only.

[1] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/kernel.lnx.5.4.r56-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L335
[2} https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/blob/kernel.lnx.5.15.r49-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L127

Cc: stable@vger.kernel.org
Fixes: 652f1813c113 ("clk: qcom: gcc: Add global clock controller driver for QCS404")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
---
Note: due to a bug in the clk_alpha_pll_configure() function, the following
patch is also needed in order for this fix to take effect:

https://lore.kernel.org/all/20241019-qcs615-mm-clockcontroller-v1-1-4cfb96d779ae@quicinc.com/
---
 drivers/clk/qcom/gcc-qcs404.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/qcom/gcc-qcs404.c b/drivers/clk/qcom/gcc-qcs404.c
index c3cfd572e7c1e0a987519be2cb2050c9bc7992c7..5ca003c9bfba89bee2e626b3c35936452cc02765 100644
--- a/drivers/clk/qcom/gcc-qcs404.c
+++ b/drivers/clk/qcom/gcc-qcs404.c
@@ -131,6 +131,7 @@ static struct clk_alpha_pll gpll1_out_main = {
 /* 930MHz configuration */
 static const struct alpha_pll_config gpll3_config = {
 	.l = 48,
+	.alpha_hi = 0x70,
 	.alpha = 0x0,
 	.alpha_en_mask = BIT(24),
 	.post_div_mask = 0xf << 8,

---
base-commit: 03dc72319cee7d0dfefee9ae7041b67732f6b8cd
change-id: 20241021-fix-gcc-qcs404-gpll3-f314335c8ecf

Best regards,
-- 
Gabor Juhos <j4g8y7@gmail.com>

Re: [PATCH] clk: qcom: gcc-qcs404: fix initial rate of GPLL3

[Bryan O'Donoghue]

On 22/10/2024 10:45, Gabor Juhos wrote:
> The comment before the config of the GPLL3 PLL says that the
> PLL should run at 930 MHz. In contrary to this, calculating
> the frequency from the current configuration values by using
> 19.2 MHz as input frequency defined in 'qcs404.dtsi', it gives
> 921.6 MHz:
> 
>    $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x0
>    $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
>    921600000.00000000000000000000
> 
> Set 'alpha_hi' in the configuration to a value used in downstream
> kernels [1][2] in order to get the correct output rate:
> 
>    $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x70
>    $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
>    930000000.00000000000000000000
> 
> The change is based on static code analysis, compile tested only.
> 
> [1] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/kernel.lnx.5.4.r56-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L335
> [2} https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/blob/kernel.lnx.5.15.r49-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L127
> 
> Cc: stable@vger.kernel.org
> Fixes: 652f1813c113 ("clk: qcom: gcc: Add global clock controller driver for QCS404")
> Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
It should be possible to test / verify this change with debugcc on qcs404

https://github.com/linux-msm/debugcc/blob/master/qcs404.c

---
bod

Re: [PATCH] clk: qcom: gcc-qcs404: fix initial rate of GPLL3

[Gabor Juhos]

Hi Bryan,

2024. 10. 22. 11:53 keltezéssel, Bryan O'Donoghue írta:
> On 22/10/2024 10:45, Gabor Juhos wrote:
>> The comment before the config of the GPLL3 PLL says that the
>> PLL should run at 930 MHz. In contrary to this, calculating
>> the frequency from the current configuration values by using
>> 19.2 MHz as input frequency defined in 'qcs404.dtsi', it gives
>> 921.6 MHz:
>>
>>    $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x0
>>    $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
>>    921600000.00000000000000000000
>>
>> Set 'alpha_hi' in the configuration to a value used in downstream
>> kernels [1][2] in order to get the correct output rate:
>>
>>    $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x70
>>    $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
>>    930000000.00000000000000000000
>>
>> The change is based on static code analysis, compile tested only.
>>
>> [1] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/
>> kernel.lnx.5.4.r56-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L335
>> [2} https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/blob/
>> kernel.lnx.5.15.r49-rel/drivers/clk/qcom/gcc-qcs404.c?ref_type=heads#L127
>>
>> Cc: stable@vger.kernel.org
>> Fixes: 652f1813c113 ("clk: qcom: gcc: Add global clock controller driver for
>> QCS404")
>> Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
> It should be possible to test / verify this change with debugcc on qcs404
> 
> https://github.com/linux-msm/debugcc/blob/master/qcs404.c

Thank you for the suggestion. Unfortunately, I have no suitable hardware to test
that.

-Gabor

Re: [PATCH] clk: qcom: gcc-qcs404: fix initial rate of GPLL3

[Bjorn Andersson]

On Tue, 22 Oct 2024 11:45:56 +0200, Gabor Juhos wrote:
> The comment before the config of the GPLL3 PLL says that the
> PLL should run at 930 MHz. In contrary to this, calculating
> the frequency from the current configuration values by using
> 19.2 MHz as input frequency defined in 'qcs404.dtsi', it gives
> 921.6 MHz:
> 
>   $ xo=19200000; l=48; alpha=0x0; alpha_hi=0x0
>   $ echo "$xo * ($((l)) + $(((alpha_hi << 32 | alpha) >> 8)) / 2^32)" | bc -l
>   921600000.00000000000000000000
> 
> [...]

Applied, thanks!

[1/1] clk: qcom: gcc-qcs404: fix initial rate of GPLL3
      commit: 36d202241d234fa4ac50743510d098ad52bd193a

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>