Re: [PATCH v3 08/14] hw/i2c/pmbus: Add idle state to return 0xff's

[Titus Rwantare]

On Wed, 29 Jun 2022 at 21:52, Peter Delevoryas <me@pjd.dev> wrote:
>
> From: Peter Delevoryas <pdel@fb.com>
>
> Signed-off-by: Peter Delevoryas <pdel@fb.com>
> ---
>  hw/i2c/pmbus_device.c         | 9 +++++++++
>  include/hw/i2c/pmbus_device.h | 7 +++++++
>  2 files changed, 16 insertions(+)
>
> diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
> index 62885fa6a1..f89fea65f3 100644
> --- a/hw/i2c/pmbus_device.c
> +++ b/hw/i2c/pmbus_device.c
> @@ -261,6 +261,11 @@ void pmbus_check_limits(PMBusDevice *pmdev)
>      }
>  }
>
> +void pmbus_idle(PMBusDevice *pmdev)
> +{
> +    pmdev->code = PMBUS_IDLE_STATE;
> +}
> +
>  /* assert the status_cml error upon receipt of malformed command */
>  static void pmbus_cml_error(PMBusDevice *pmdev)
>  {
> @@ -984,6 +989,10 @@ static uint8_t pmbus_receive_byte(SMBusDevice *smd)
>          }
>          break;
>
> +    case PMBUS_IDLE_STATE:
> +        pmbus_send8(pmdev, PMBUS_ERR_BYTE);
> +        break;
> +
>      case PMBUS_CLEAR_FAULTS:              /* Send Byte */
>      case PMBUS_PAGE_PLUS_WRITE:           /* Block Write-only */
>      case PMBUS_STORE_DEFAULT_ALL:         /* Send Byte */
> diff --git a/include/hw/i2c/pmbus_device.h b/include/hw/i2c/pmbus_device.h
> index 0f4d6b3fad..93f5d57c9d 100644
> --- a/include/hw/i2c/pmbus_device.h
> +++ b/include/hw/i2c/pmbus_device.h
> @@ -155,6 +155,7 @@ enum pmbus_registers {
>      PMBUS_MFR_MAX_TEMP_1            = 0xC0, /* R/W word */
>      PMBUS_MFR_MAX_TEMP_2            = 0xC1, /* R/W word */
>      PMBUS_MFR_MAX_TEMP_3            = 0xC2, /* R/W word */
> +    PMBUS_IDLE_STATE                = 0xFF,
>  };
>
>  /* STATUS_WORD */
> @@ -527,6 +528,12 @@ int pmbus_page_config(PMBusDevice *pmdev, uint8_t 
> page_index, uint64_t flags);
>   */
>  void pmbus_check_limits(PMBusDevice *pmdev);
>
> +/**
> + * Enter an idle state where only the PMBUS_ERR_BYTE will be returned
> + * indefinitely until a new command is issued.
> + */
> +void pmbus_idle(PMBusDevice *pmdev);
> +
>  extern const VMStateDescription vmstate_pmbus_device;
>
>  #define VMSTATE_PMBUS_DEVICE(_field, _state) {                       \
> --
> 2.37.0
>

Reviewed-by: Titus Rwantare <titusr@google.com>