source: GPL/trunk/alsa-kernel/pci/hda/thinkpad_helper.c

// SPDX-License-Identifier: GPL-2.0
/* Helper functions for Thinkpad LED control;
 * to be included from codec driver
 */

#if IS_ENABLED(CONFIG_THINKPAD_ACPI)

#include <linux/acpi.h>
#include <linux/leds.h>

static bool is_thinkpad(struct hda_codec *codec)
{
        return (codec->core.subsystem_id >> 16 == 0x17aa) &&
               (acpi_dev_found("LEN0068") || acpi_dev_found("LEN0268") ||
                acpi_dev_found("IBM0068"));
}

static void hda_fixup_thinkpad_acpi(struct hda_codec *codec,
                                    const struct hda_fixup *fix, int action)
{
        if (action == HDA_FIXUP_ACT_PRE_PROBE) {
                if (!is_thinkpad(codec))
                        return;
                snd_hda_gen_add_mute_led_cdev(codec, NULL);
                snd_hda_gen_add_micmute_led_cdev(codec, NULL);
        }
}

#else /* CONFIG_THINKPAD_ACPI */

static void hda_fixup_thinkpad_acpi(struct hda_codec *codec,
                                    const struct hda_fixup *fix, int action)
{
}

#endif /* CONFIG_THINKPAD_ACPI */