Re: [PATCH 10/10] mfd: cros_ec: Add convenience struct to define autodetectable CrOS EC subdevices

[Gwendal Grignou]

On Tue, Jun 4, 2019 at 8:20 AM Enric Balletbo i Serra
<enric.balletbo@xxxxxxxxxxxxx> wrote:
>
> The CrOS EC is gaining lots of subdevices that are autodetectable by
> sending the EC_FEATURE_GET_CMD, it takes fair amount of boiler plate
> code to add those devices. So, add a struct that can be used to quickly
> add new subdevices without having to duplicate code.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> ---
>
>  drivers/mfd/cros_ec_dev.c | 132 +++++++++++++++++++++-----------------
>  1 file changed, 74 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 6fcfc8f17e03..49e4ab7ebb71 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -34,6 +34,18 @@ struct cros_feature_to_name {
>         const char *desc;
>  };
>
> +/**
> + * cros_feature_to_cells - CrOS feature id to mfd cells association.
> + * @id: The feature identifier.
> + * @mfd_cells: Pointer to the array of mfd cells that needs to be added.
> + * @num_cells: Number of mfd cells into the array.
> + */
> +struct cros_feature_to_cells {
> +       unsigned int id;
> +       const struct mfd_cell *mfd_cells;
> +       unsigned int num_cells;
> +};
> +
>  static const struct cros_feature_to_name cros_mcu_devices[] = {
>         {
>                 .id     = EC_FEATURE_FINGERPRINT,
> @@ -52,6 +64,48 @@ static const struct cros_feature_to_name cros_mcu_devices[] = {
>         },
>  };
>
> +static const struct mfd_cell cros_ec_cec_cells[] = {
> +       { .name = "cros-ec-cec", },
> +};
> +
> +static const struct mfd_cell cros_ec_rtc_cells[] = {
> +       { .name = "cros-ec-rtc", },
> +};
> +
> +static const struct mfd_cell cros_usbpd_charger_cells[] = {
> +       { .name = "cros-usbpd-charger", },
> +       { .name = "cros-usbpd-logger", },
> +};
> +
> +static const struct cros_feature_to_cells cros_subdevices[] = {
> +       {
> +               .id             = EC_FEATURE_CEC,
> +               .mfd_cells      = cros_ec_cec_cells,
> +               .num_cells      = ARRAY_SIZE(cros_ec_cec_cells),
> +       },
> +       {
> +               .id             = EC_FEATURE_RTC,
> +               .mfd_cells      = cros_ec_rtc_cells,
> +               .num_cells      = ARRAY_SIZE(cros_ec_rtc_cells),
> +       },
> +       {
> +               .id             = EC_FEATURE_USB_PD,
> +               .mfd_cells      = cros_usbpd_charger_cells,
> +               .num_cells      = ARRAY_SIZE(cros_usbpd_charger_cells),
> +       },
> +};
> +
> +static const struct mfd_cell cros_ec_platform_cells[] = {
> +       { .name = "cros-ec-chardev", },
> +       { .name = "cros-ec-debugfs", },
> +       { .name = "cros-ec-lightbar", },
> +       { .name = "cros-ec-sysfs", },
> +};
> +
> +static const struct mfd_cell cros_ec_vbc_cells[] = {
> +       { .name = "cros-ec-vbc", }
> +};
> +
>  static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
>  {
>         struct cros_ec_command *msg;
> @@ -211,30 +265,6 @@ static void cros_ec_sensors_register(struct cros_ec_dev *ec)
>         kfree(msg);
>  }
>
> -static const struct mfd_cell cros_ec_cec_cells[] = {
> -       { .name = "cros-ec-cec" }
> -};
> -
> -static const struct mfd_cell cros_ec_rtc_cells[] = {
> -       { .name = "cros-ec-rtc" }
> -};
> -
> -static const struct mfd_cell cros_usbpd_charger_cells[] = {
> -       { .name = "cros-usbpd-charger" },
> -       { .name = "cros-usbpd-logger" },
> -};
> -
> -static const struct mfd_cell cros_ec_platform_cells[] = {
> -       { .name = "cros-ec-chardev" },
> -       { .name = "cros-ec-debugfs" },
> -       { .name = "cros-ec-lightbar" },
> -       { .name = "cros-ec-sysfs" },
> -};
> -
> -static const struct mfd_cell cros_ec_vbc_cells[] = {
> -       { .name = "cros-ec-vbc" }
> -};
> -
>  static int ec_device_probe(struct platform_device *pdev)
>  {
>         int retval = -ENOMEM;
> @@ -292,42 +322,28 @@ static int ec_device_probe(struct platform_device *pdev)
>         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
>                 cros_ec_sensors_register(ec);
>
> -       /* Check whether this EC instance has CEC host command support */
> -       if (cros_ec_check_features(ec, EC_FEATURE_CEC)) {
> -               retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> -                                        cros_ec_cec_cells,
> -                                        ARRAY_SIZE(cros_ec_cec_cells),
> -                                        NULL, 0, NULL);
> -               if (retval)
> -                       dev_err(ec->dev,
> -                               "failed to add cros-ec-cec device: %d\n",
> -                               retval);
> -       }
> -
> -       /* Check whether this EC instance has RTC host command support */
> -       if (cros_ec_check_features(ec, EC_FEATURE_RTC)) {
> -               retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> -                                        cros_ec_rtc_cells,
> -                                        ARRAY_SIZE(cros_ec_rtc_cells),
> -                                        NULL, 0, NULL);
> -               if (retval)
> -                       dev_err(ec->dev,
> -                               "failed to add cros-ec-rtc device: %d\n",
> -                               retval);
> -       }
> -
> -       /* Check whether this EC instance has the PD charge manager */
> -       if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
> -               retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> -                                        cros_usbpd_charger_cells,
> -                                        ARRAY_SIZE(cros_usbpd_charger_cells),
> -                                        NULL, 0, NULL);
> -               if (retval)
> -                       dev_err(ec->dev,
> -                               "failed to add cros-usbpd-charger device: %d\n",
> -                               retval);
> +       /*
> +        * The following subdevices can be detected by sending the
> +        * EC_FEATURE_GET_CMD Embedded Controller device.
> +        */
> +       for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
> +               if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
> +                       retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> +                                                cros_subdevices[i].mfd_cells,
> +                                                cros_subdevices[i].num_cells,
> +                                                NULL, 0, NULL);
Nit: you can replace mfd_add_devices() call  by mfd_add_hotplug_devices().
> +                       if (retval)
> +                               dev_err(ec->dev,
> +                                       "failed to add %s subdevice: %d\n",
> +                                       cros_subdevices[i].mfd_cells->name,
> +                                       retval);
> +               }
>         }
>
> +       /*
> +        * The following subdevices cannot be detected by sending the
> +        * EC_FEATURE_GET_CMD to the Embedded Controller device.
> +        */
>         retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
>                                  cros_ec_platform_cells,
>                                  ARRAY_SIZE(cros_ec_platform_cells),
> --
> 2.20.1
>