Re: [PATCH v2 02/13] ACPICA: Read LVR from the I2C resource descriptor

On Thu, Apr 9, 2026 at 12:59 PM Akhil R <[email protected]> wrote:
>
> ACPI 6.3 specifies byte 8 of I2C Serial Bus Connection descriptor to be
> used for Legacy Virtual Register (LVR) data as specified in the MIPI
> I3C Specification for an I2C device connected to an I3C Host Controller.
> LVR will be read by I3C host controller drivers and it provides details
> about the specific speed and 50ns spike filter capabilities of I2C
> devices.
>
> Update the rsconvert_info to include this field. For I2C devices on an
> I2C bus, this field is Reserved and unused.
>
> This commit is the result of squashing the following:
> ACPICA commit 70082dc8fc847673ac7f4bbb1541776730f0b63e
> ACPICA commit e62e74baf7e08cf059ec82049aeccd565b24d661
> ACPICA commit c404118235108012cad396c834b5aabe2dd1b51a
> ACPICA commit 7650d4a889ea7907060bfce89f4f780ce83e7b28
> ACPICA commit 014fa9f2dbcc6b1bd42a4a4a6f6705d9cf7d460b
>
> Link: https://github.com/acpica/acpica/commit/70082dc8
> Link: https://github.com/acpica/acpica/commit/b3c38dc9
> Signed-off-by: Akhil R <[email protected]>

Acked-by: Rafael J. Wysocki (Intel) <[email protected]> # ACPI

> ---
>  drivers/acpi/acpica/rsserial.c | 6 +++++-
>  include/acpi/acrestyp.h        | 1 +
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/acpica/rsserial.c b/drivers/acpi/acpica/rsserial.c
> index 279bfa27da94..c06e918ab889 100644
> --- a/drivers/acpi/acpica/rsserial.c
> +++ b/drivers/acpi/acpica/rsserial.c
> @@ -315,7 +315,7 @@ struct acpi_rsconvert_info acpi_rs_convert_csi2_serial_bus[14] = {
>   *
>   ******************************************************************************/
>
> -struct acpi_rsconvert_info acpi_rs_convert_i2c_serial_bus[17] = {
> +struct acpi_rsconvert_info acpi_rs_convert_i2c_serial_bus[18] = {
>         {ACPI_RSC_INITGET, ACPI_RESOURCE_TYPE_SERIAL_BUS,
>          ACPI_RS_SIZE(struct acpi_resource_i2c_serialbus),
>          ACPI_RSC_TABLE_SIZE(acpi_rs_convert_i2c_serial_bus)},
> @@ -391,6 +391,10 @@ struct acpi_rsconvert_info acpi_rs_convert_i2c_serial_bus[17] = {
>          AML_OFFSET(i2c_serial_bus.type_specific_flags),
>          0},
>
> +       {ACPI_RSC_MOVE8, ACPI_RS_OFFSET(data.i2c_serial_bus.lvr),
> +        AML_OFFSET(i2c_serial_bus.type_specific_flags) + 1,
> +        1},
> +
>         {ACPI_RSC_MOVE32, ACPI_RS_OFFSET(data.i2c_serial_bus.connection_speed),
>          AML_OFFSET(i2c_serial_bus.connection_speed),
>          1},
> diff --git a/include/acpi/acrestyp.h b/include/acpi/acrestyp.h
> index 842f932e2c2b..38a19b1d19ac 100644
> --- a/include/acpi/acrestyp.h
> +++ b/include/acpi/acrestyp.h
> @@ -423,6 +423,7 @@ struct acpi_resource_i2c_serialbus {
>         ACPI_RESOURCE_SERIAL_COMMON u8 access_mode;
>         u16 slave_address;
>         u32 connection_speed;
> +       u8 lvr;
>  };
>
>  /* Values for access_mode field above */
> --
> 2.50.1
>
>