Re: [PATCH] platform/x86: int3472: Use actual clock frequency for DSM method

Bingbu Cao
2025-12-05T10:19:05Z

Hao,

Thanks for the patch.

On 12/5/25 5:51 PM, Hao Yao wrote:
> The third argument (args[2]) to the _DSM method was hardcoded to 1,
> which corresponds to 19.2MHz. However, this argument should reflect
> the actual clock frequency from the sensor's ACPI data.
>
> According to the DSM specification:
> - 1 = 19.2MHz
> - 3 = 24MHz
>

What are the value 0 and 2? I think there are other frequencies.

> Read the frequency from clk->frequency and set the DSM argument
> accordingly, with 19.2MHz as the default for unsupported frequencies.
>
> This ensures the sensor receives the correct clock frequency as
> specified in its ACPI configuration.
>
> Signed-off-by: Hao Yao <hao.yao@intel.com>
> ---
> .../x86/intel/int3472/clk_and_regulator.c | 21 ++++++++++++++++++-
> 1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
> index 9e052b164a1a..0502876284ee 100644
> --- a/drivers/platform/x86/intel/int3472/clk_and_regulator.c
> +++ b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
> @@ -19,23 +19,42 @@ static const guid_t img_clk_guid =
> GUID_INIT(0x82c0d13a, 0x78c5, 0x4244,
> 0x9b, 0xb1, 0xeb, 0x8b, 0x53, 0x9a, 0x8d, 0x11);
>
> +/*
> + * The PCH clock frequency argument to the _DSM method:
> + * PCH_CLK_FREQ_19M = 19.2MHz (default)
> + * PCH_CLK_FREQ_24M = 24MHz
> + */
> +#define PCH_CLK_FREQ_19M 1

I like 19P2MHZ.

> +#define PCH_CLK_FREQ_24M 3
> +
> static void skl_int3472_enable_clk(struct int3472_clock *clk, int enable)
> {
> struct int3472_discrete_device *int3472 = to_int3472_device(clk);
> union acpi_object args[3];
> union acpi_object argv4;
> + u32 dsm_freq_arg;
>
> if (clk->ena_gpio) {
> gpiod_set_value_cansleep(clk->ena_gpio, enable);
> return;
> }
>
> + switch (clk->frequency) {
> + case 24000000:
> + dsm_freq_arg = PCH_CLK_FREQ_24M;
> + break;
> + case 19200000:
> + default:
> + dsm_freq_arg = PCH_CLK_FREQ_19M;
> + break;
> + }
> +
> args[0].integer.type = ACPI_TYPE_INTEGER;
> args[0].integer.value = clk->imgclk_index;
> args[1].integer.type = ACPI_TYPE_INTEGER;
> args[1].integer.value = enable;
> args[2].integer.type = ACPI_TYPE_INTEGER;
> - args[2].integer.value = 1;
> + args[2].integer.value = dsm_freq_arg;
>
> argv4.type = ACPI_TYPE_PACKAGE;
> argv4.package.count = 3;
>

--
Best regards,
Bingbu Cao