> +#if IS_ENABLED(CONFIG_SCSI_MAC_ESP) || IS_ENABLED(CONFIG_SCSI_ZORRO_ESP)

Please add a new CONFIG_SCSI_ESP_PIO symbol that is selected by
the mac and zorro drivers instead.

> +	pr_err("FIFO is empty (sreg %02x)\n", esp_read8(ESP_STATUS));

This should probably use dev_err (at least with my series).