linux-kernel - Re: [PATCH v2] clk: meson-g12a: fix bit range for fixed sys and hifi pll

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Message-ID: <1jcy8j6bna.fsf@starbuckisacylon.baylibre.com>
Date: Mon, 25 Aug 2025 10:36:25 +0200
From: Jerome Brunet <jbrunet@...libre.com>
To: Da Xue <da@...re.computer>
Cc: Neil Armstrong <neil.armstrong@...aro.org>,  Michael Turquette
 <mturquette@...libre.com>,  Stephen Boyd <sboyd@...nel.org>,  Kevin Hilman
 <khilman@...libre.com>,  Martin Blumenstingl
 <martin.blumenstingl@...glemail.com>,  Jian Hu <jian.hu@...ogic.com>,
  linux-amlogic@...ts.infradead.org,  linux-clk@...r.kernel.org,
  linux-arm-kernel@...ts.infradead.org,  linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] clk: meson-g12a: fix bit range for fixed sys and
 hifi pll

On Thu 21 Aug 2025 at 20:22, Da Xue <da@...re.computer> wrote:

> The bit range 17:0 does not match the datasheet for A311D / S905D3.
> Change the bit range to 18:0 for FIX and HIFI PLLs to match datasheet.
>
> The frac field is missing for sys pll so add that as well.
>
> Patched:
>
> + sudo cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq \
> /sys/devices/system/cpu/cpufreq/policy2/cpuinfo_cur_freq
> 996999
> 500000
> + sudo cat /sys/kernel/debug/meson-clk-msr/measure_summary
> + grep -i '\(sys_\|hifi_\|fixed_\)pll'
>  hifi_pll                      0    +/-1562Hz
>  sys_pll_div16                 0    +/-1562Hz
>  sys_pll_cpub_div16            0    +/-1562Hz
> + sudo cat /sys/kernel/debug/clk/clk_summary
> + grep -i '\(sys_\|hifi_\|fixed_\)pll'
>     hifi_pll_dco                     0       0        0        0
>        hifi_pll                      0       0        0        0
>     sys_pll_dco                      1       1        0        3999999985
>        sys_pll                       0       0        0        499999999
>           sys_pll_div16_en           0       0        0        499999999
>              sys_pll_div16           0       0        0        31249999
>     fixed_pll_dco                    1       1        1        3987999985
>        fixed_pll                     3       3        1        1993999993
>
> Unpatch:
>
> + sudo cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq \
> /sys/devices/system/cpu/cpufreq/policy2/cpuinfo_cur_freq
> 1000000
> 500000
> + sudo cat /sys/kernel/debug/meson-clk-msr/measure_summary
> + grep -i '\(sys_\|hifi_\|fixed_\)pll'
>  hifi_pll                      0    +/-1562Hz
>  sys_pll_div16                 0    +/-1562Hz
>  sys_pll_cpub_div16            0    +/-1562Hz
> + sudo cat /sys/kernel/debug/clk/clk_summary
> + grep -i '\(sys_\|hifi_\|fixed_\)pll'
>     hifi_pll_dco                     0       0        0        0
>        hifi_pll                      0       0        0        0
>     sys_pll_dco                      1       1        0        4800000000
>        sys_pll                       0       0        0        1200000000
>           sys_pll_div16_en           0       0        0        1200000000
>              sys_pll_div16           0       0        0        75000000
>     fixed_pll_dco                    1       1        1        3999999939
>        fixed_pll                     3       3        1        1999999970
>
> Fixes: 085a4ea93d54 ("clk: meson: g12a: add peripheral clock controller")
> Signed-off-by: Da Xue <da@...re.computer>
> ---
>  drivers/clk/meson/g12a.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
> index 66f0e817e416..f78cca619ca5 100644
> --- a/drivers/clk/meson/g12a.c
> +++ b/drivers/clk/meson/g12a.c
> @@ -157,7 +157,7 @@ static struct clk_regmap g12a_fixed_pll_dco = {
>  		.frac = {
>  			.reg_off = HHI_FIX_PLL_CNTL1,
>  			.shift   = 0,
> -			.width   = 17,
> +			.width   = 19,
>  		},
>  		.l = {
>  			.reg_off = HHI_FIX_PLL_CNTL0,
> @@ -223,6 +223,11 @@ static struct clk_regmap g12a_sys_pll_dco = {
>  			.shift   = 10,
>  			.width   = 5,
>  		},
> +		.frac = {
> +			.reg_off = HHI_SYS_PLL_CNTL1,
> +			.shift   = 0,
> +			.width   = 19,
> +		},
>  		.l = {
>  			.reg_off = HHI_SYS_PLL_CNTL0,
>  			.shift   = 31,
> @@ -1901,7 +1906,7 @@ static struct clk_regmap g12a_hifi_pll_dco = {
>  		.frac = {
>  			.reg_off = HHI_HIFI_PLL_CNTL1,
>  			.shift   = 0,
> -			.width   = 17,
> +			.width   = 19,
>  		},
>  		.l = {
>  			.reg_off = HHI_HIFI_PLL_CNTL0,

Thanks for this.

While this is indeed the same topic, this is doing 2 things at once.
Could you please split this, fixup in one change, adding the missing
frac in another ?

It is much easier to handle in case something needs to be reverted.

-- 
Jerome