Re: [PATCH v2 3/4] hw/adc: Add an ADC module for NPCM7XX

[Hao Wu]

Thanks for your comment! We'll incorporate them into our next patch version.

We plan to let the user use QOM get/set QMP commands to control ADC/PWM values, similar to hw/misc/tmp105.c. The user can set a voltage value as input using QOM-set, and the QEMU guest can read the converted value through this module. Similar for PWM, the user can read the duty-cycle and frequency using QOM-get. The user can also run a third-party simulator and alter these values during execution. Our test code also shows how to deal with these values.

If you have a better suggestion, please let us know.

On Sun, Dec 13, 2020 at 3:47 AM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:

On 12/11/20 11:22 PM, Hao Wu via wrote:
> The ADC is part of NPCM7XX Module. Its behavior is controled by the
> ADC_CON register. It converts one of the eight analog inputs into a
> digital input and stores it in the ADC_DATA register when enabled.
>
> Reviewed-by: Havard Skinnemoen <hskinnemoen@google.com>
> Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
> Signed-off-by: Hao Wu <wuhaotsh@google.com>
> ---
>  docs/system/arm/nuvoton.rst    |   2 +-
>  hw/adc/meson.build             |   1 +
>  hw/adc/npcm7xx_adc.c           | 318 ++++++++++++++++++++++++++
>  hw/arm/npcm7xx.c               |  24 +-
>  include/hw/adc/npcm7xx_adc.h   |  72 ++++++
>  include/hw/arm/npcm7xx.h       |   2 +
>  tests/qtest/meson.build        |   3 +-
>  tests/qtest/npcm7xx_adc-test.c | 400 +++++++++++++++++++++++++++++++++
>  8 files changed, 819 insertions(+), 3 deletions(-)
>  create mode 100644 hw/adc/npcm7xx_adc.c
>  create mode 100644 include/hw/adc/npcm7xx_adc.h
>  create mode 100644 tests/qtest/npcm7xx_adc-test.c
...

> +static void npcm7xx_adc_init(Object *obj)
> +{
> +    NPCM7xxADCState *s = NPCM7XX_ADC(obj);
> +    SysBusDevice *sbd = &s->parent;
> +    int i;
> +
> +    sysbus_init_irq(sbd, &s->irq);
> +
> +    timer_init_ns(&s->conv_timer, QEMU_CLOCK_VIRTUAL,
> +            npcm7xx_adc_convert_done, s);
> +    timer_init_ns(&s->reset_timer, QEMU_CLOCK_VIRTUAL,
> +            npcm7xx_adc_reset_done, s);
> +    memory_region_init_io(&s->iomem, obj, &npcm7xx_adc_ops, s,
> +                          TYPE_NPCM7XX_ADC, 4 * KiB);
> +    sysbus_init_mmio(sbd, &s->iomem);
> +    s->clock = qdev_init_clock_in(DEVICE(s), "clock", NULL, NULL);
> +
> +    for (i = 0; i < NPCM7XX_ADC_NUM_INPUTS; ++i) {
> +        object_property_add_uint32_ptr(obj, "adci[*]",
> +                &s->adci[i], OBJ_PROP_FLAG_WRITE);

How do you use this, any example?

FWIW I'm experimenting with other ADC to use the "audio/audio.h"
API (which is not voice/audio specific, but generic DSP), then
I can pass any QEMU source and consume it using AUD_read() to fill
the ADC buffer (device sram or in main ram).

But I'm doing that alone during my free time, so don't expect it
any time soon :(

> +    }
> +    object_property_add_uint32_ptr(obj, "vref",
> +            &s->vref, OBJ_PROP_FLAG_WRITE);
> +    npcm7xx_adc_calibrate(s);
> +}