Re: [PATCH v4 1/7] spmi: Implement spmi_subdevice_alloc_and_add() and devm variant

From: Uwe Kleine-König
Date: Tue Sep 16 2025 - 09:26:04 EST


Hello AngeloGioacchino,

On Tue, Sep 16, 2025 at 10:44:39AM +0200, AngeloGioacchino Del Regno wrote:
> +/**
> + * spmi_subdevice_alloc_and_add(): Allocate and add a new SPMI sub-device
> + * @sparent: SPMI parent device with previously registered SPMI controller
> + *
> + * Returns:
> + * Pointer to newly allocated SPMI sub-device for success or negative ERR_PTR.
> + */
> +struct spmi_subdevice *spmi_subdevice_alloc_and_add(struct spmi_device *sparent)
> +{
> + struct spmi_subdevice *sub_sdev;
> + struct spmi_device *sdev;
> + int ret;
> +
> + sub_sdev = kzalloc(sizeof(*sub_sdev), GFP_KERNEL);
> + if (!sub_sdev)
> + return ERR_PTR(-ENOMEM);
> +
> + ret = ida_alloc(&spmi_subdevice_ida, GFP_KERNEL);
> + if (ret < 0) {
> + kfree(sub_sdev);
> + return ERR_PTR(ret);
> + }
> +
> + sdev = &sub_sdev->sdev;
> + sdev->ctrl = sparent->ctrl;
> + device_initialize(&sdev->dev);
> + sdev->dev.parent = &sparent->dev;
> + sdev->dev.bus = &spmi_bus_type;
> + sdev->dev.type = &spmi_subdev_type;
> +
> + sub_sdev->devid = ret;
> + sdev->usid = sparent->usid;
> +
> + ret = dev_set_name(&sdev->dev, "%d-%02x.%d.auto",
> + sdev->ctrl->nr, sdev->usid, sub_sdev->devid);

If I understand correctly sub_sdev->devid is globally unique. I wonder
if a namespace that is specific to the parent spmi device would be more
sensible?!

> + if (ret)
> + goto err_put_dev;
> +
> + ret = device_add(&sdev->dev);
> + if (ret) {
> + dev_err(&sdev->dev, "Can't add %s, status %d\n",

I'd use %pe instead of %d here.

> + dev_name(&sdev->dev), ret);
> + goto err_put_dev;
> + }
> +
> + return sub_sdev;
> +
> +err_put_dev:
> + put_device(&sdev->dev);
> + return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_NS_GPL(spmi_subdevice_alloc_and_add, "SPMI");
> +

Best regards
Uwe

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