ASoC: SOF: acpi led support for switch controls

Currently sof doesn't support acpi leds with mute switches. So implement
acpi leds following quite shamelessly existing HDA implementation by
Takashi Iwai.

Mute leds can be enabled in topology by adding led and direction token
in switch control private data.
Signed-off-by: Jaska Uimonen <jaska.uimonen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191008164443.1358-10-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/uapi/sound/sof/tokens.h

@@ -113,4 +113,8 @@
 /* ESAI */
 #define SOF_TKN_IMX_ESAI_MCLK_ID		1100
 
+/* Led control for mute switches */
+#define SOF_TKN_MUTE_LED_USE			1300
+#define SOF_TKN_MUTE_LED_DIRECTION		1301
+
 #endif

sound/soc/sof/control.c

@@ -11,8 +11,37 @@
 /* Mixer Controls */
 
 #include <linux/pm_runtime.h>
+#include <linux/leds.h>
 #include "sof-priv.h"
 
+static void update_mute_led(struct snd_sof_control *scontrol,
+			    struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_value *ucontrol)
+{
+	unsigned int temp = 0;
+	unsigned int mask;
+	int i;
+
+	mask = 1U << snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
+
+	for (i = 0; i < scontrol->num_channels; i++) {
+		if (ucontrol->value.integer.value[i]) {
+			temp |= mask;
+			break;
+		}
+	}
+
+	if (temp == scontrol->led_ctl.led_value)
+		return;
+
+	scontrol->led_ctl.led_value = temp;
+
+	if (!scontrol->led_ctl.direction)
+		ledtrig_audio_set(LED_AUDIO_MUTE, temp ? LED_OFF : LED_ON);
+	else
+		ledtrig_audio_set(LED_AUDIO_MICMUTE, temp ? LED_OFF : LED_ON);
+}
+
 static inline u32 mixer_to_ipc(unsigned int value, u32 *volume_map, int size)
 {
 	if (value >= size)
@@ -112,6 +141,9 @@ int snd_sof_switch_put(struct snd_kcontrol *kcontrol,
 		cdata->chanv[i].channel = i;
 	}
 
+	if (scontrol->led_ctl.use_led)
+		update_mute_led(scontrol, kcontrol, ucontrol);
+
 	/* notify DSP of mixer updates */
 	if (pm_runtime_active(sdev->dev))
 		snd_sof_ipc_set_get_comp_data(sdev->ipc, scontrol,

sound/soc/sof/sof-priv.h

@@ -15,6 +15,7 @@
 
 #include <sound/hdaudio.h>
 #include <sound/soc.h>
+#include <sound/control.h>
 
 #include <sound/sof.h>
 #include <sound/sof/stream.h> /* needs to be included before control.h */
@@ -310,6 +311,12 @@ struct snd_sof_pcm {
 	bool prepared[2]; /* PCM_PARAMS set successfully */
 };
 
+struct snd_sof_led_control {
+	unsigned int use_led;
+	unsigned int direction;
+	unsigned int led_value;
+};
+
 /* ALSA SOF Kcontrol device */
 struct snd_sof_control {
 	struct snd_sof_dev *sdev;
@@ -324,6 +331,8 @@ struct snd_sof_control {
 	u32 *volume_table; /* volume table computed from tlv data*/
 
 	struct list_head list;	/* list in sdev control list */
+
+	struct snd_sof_led_control led_ctl;
 };
 
 /* ASoC SOF DAPM widget */

sound/soc/sof/topology.c

@@ -682,6 +682,14 @@ static const struct sof_topology_token dmic_pdm_tokens[] = {
 static const struct sof_topology_token hda_tokens[] = {
 };
 
+/* Leds */
+static const struct sof_topology_token led_tokens[] = {
+	{SOF_TKN_MUTE_LED_USE, SND_SOC_TPLG_TUPLE_TYPE_WORD, get_token_u32,
+	 offsetof(struct snd_sof_led_control, use_led), 0},
+	{SOF_TKN_MUTE_LED_DIRECTION, SND_SOC_TPLG_TUPLE_TYPE_WORD,
+	 get_token_u32, offsetof(struct snd_sof_led_control, direction), 0},
+};
+
 static void sof_parse_uuid_tokens(struct snd_soc_component *scomp,
 				  void *object,
 				  const struct sof_topology_token *tokens,
@@ -944,6 +952,11 @@ static int sof_control_load_volume(struct snd_soc_component *scomp,
 	}
 
 out:
+	/* set up possible led control from mixer private data */
+	ret = sof_parse_tokens(scomp, &scontrol->led_ctl, led_tokens,
+			       ARRAY_SIZE(led_tokens), mc->priv.array,
+			       le32_to_cpu(mc->priv.size));
+
 	dev_dbg(sdev->dev, "tplg: load kcontrol index %d chans %d\n",
 		scontrol->comp_id, scontrol->num_channels);