simple-mux.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2020 Bootlin SA
  4 * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
  5 */
  6
  7#include <linux/gpio/consumer.h>
  8#include <linux/module.h>
  9#include <linux/mux/driver.h>
 10#include <linux/regulator/consumer.h>
 11#include <sound/soc.h>
 12
 13#define MUX_TEXT_SIZE	2
 14#define MUX_WIDGET_SIZE	4
 15#define MUX_ROUTE_SIZE	3
 16struct simple_mux {
 17	struct gpio_desc *gpiod_mux;
 18	unsigned int mux;
 19	const char *mux_texts[MUX_TEXT_SIZE];
 20	unsigned int idle_state;
 21	struct soc_enum mux_enum;
 22	struct snd_kcontrol_new mux_mux;
 23	struct snd_soc_dapm_widget mux_widgets[MUX_WIDGET_SIZE];
 24	struct snd_soc_dapm_route mux_routes[MUX_ROUTE_SIZE];
 25	struct snd_soc_component_driver mux_driver;
 26};
 27
 28static const char * const simple_mux_texts[MUX_TEXT_SIZE] = {
 29	"Input 1", "Input 2"
 30};
 31
 32static SOC_ENUM_SINGLE_EXT_DECL(simple_mux_enum, simple_mux_texts);
 33
 34static int simple_mux_control_get(struct snd_kcontrol *kcontrol,
 35				  struct snd_ctl_elem_value *ucontrol)
 36{
 37	struct snd_soc_dapm_context *dapm = snd_soc_dapm_kcontrol_to_dapm(kcontrol);
 38	struct snd_soc_component *c = snd_soc_dapm_to_component(dapm);
 39	struct simple_mux *priv = snd_soc_component_get_drvdata(c);
 40
 41	ucontrol->value.enumerated.item[0] = priv->mux;
 42
 43	return 0;
 44}
 45
 46static int simple_mux_control_put(struct snd_kcontrol *kcontrol,
 47				  struct snd_ctl_elem_value *ucontrol)
 48{
 49	struct snd_soc_dapm_context *dapm = snd_soc_dapm_kcontrol_to_dapm(kcontrol);
 50	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
 51	struct snd_soc_component *c = snd_soc_dapm_to_component(dapm);
 52	struct simple_mux *priv = snd_soc_component_get_drvdata(c);
 53
 54	if (ucontrol->value.enumerated.item[0] > e->items)
 55		return -EINVAL;
 56
 57	if (priv->mux == ucontrol->value.enumerated.item[0])
 58		return 0;
 59
 60	priv->mux = ucontrol->value.enumerated.item[0];
 61
 62	if (priv->idle_state != MUX_IDLE_AS_IS &&
 63	    snd_soc_dapm_get_bias_level(dapm) < SND_SOC_BIAS_PREPARE)
 64		return 0;
 65
 66	gpiod_set_value_cansleep(priv->gpiod_mux, priv->mux);
 67
 68	return snd_soc_dapm_mux_update_power(dapm, kcontrol,
 69					     ucontrol->value.enumerated.item[0],
 70					     e, NULL);
 71}
 72
 73static unsigned int simple_mux_read(struct snd_soc_component *component,
 74				    unsigned int reg)
 75{
 76	struct simple_mux *priv = snd_soc_component_get_drvdata(component);
 77
 78	return priv->mux;
 79}
 80
 81static const struct snd_kcontrol_new simple_mux_mux =
 82	SOC_DAPM_ENUM_EXT("Muxer", simple_mux_enum, simple_mux_control_get, simple_mux_control_put);
 83
 84static int simple_mux_event(struct snd_soc_dapm_widget *w,
 85			    struct snd_kcontrol *kcontrol, int event)
 86{
 87	struct snd_soc_component *c = snd_soc_dapm_to_component(w->dapm);
 88	struct simple_mux *priv = snd_soc_component_get_drvdata(c);
 89
 90	if (priv->idle_state != MUX_IDLE_AS_IS) {
 91		switch (event) {
 92		case SND_SOC_DAPM_PRE_PMU:
 93			gpiod_set_value_cansleep(priv->gpiod_mux, priv->mux);
 94			break;
 95		case SND_SOC_DAPM_POST_PMD:
 96			gpiod_set_value_cansleep(priv->gpiod_mux, priv->idle_state);
 97			break;
 98		default:
 99			break;
100		}
101	}
102
103	return 0;
104}
105
106static const struct snd_soc_dapm_widget simple_mux_dapm_widgets[MUX_WIDGET_SIZE] = {
107	SND_SOC_DAPM_INPUT("IN1"),
108	SND_SOC_DAPM_INPUT("IN2"),
109	SND_SOC_DAPM_MUX_E("MUX", SND_SOC_NOPM, 0, 0, &simple_mux_mux, // see simple_mux_probe()
110			   simple_mux_event, SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
111	SND_SOC_DAPM_OUTPUT("OUT"),
112};
113
114static const struct snd_soc_dapm_route simple_mux_dapm_routes[MUX_ROUTE_SIZE] = {
115	{ "OUT", NULL, "MUX" },
116	{ "MUX", "Input 1", "IN1" }, // see simple_mux_probe()
117	{ "MUX", "Input 2", "IN2" }, // see simple_mux_probe()
118};
119
120static int simple_mux_probe(struct platform_device *pdev)
121{
122	struct device *dev = &pdev->dev;
123	struct device_node *np = dev->of_node;
124	struct simple_mux *priv;
125	int ret;
126
127	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
128	if (!priv)
129		return -ENOMEM;
130
131	dev_set_drvdata(dev, priv);
132
133	priv->gpiod_mux = devm_gpiod_get(dev, "mux", GPIOD_OUT_LOW);
134	if (IS_ERR(priv->gpiod_mux))
135		return dev_err_probe(dev, PTR_ERR(priv->gpiod_mux),
136				     "Failed to get 'mux' gpio");
137
138	/* Copy default settings */
139	memcpy(&priv->mux_texts,	&simple_mux_texts,		sizeof(priv->mux_texts));
140	memcpy(&priv->mux_enum,		&simple_mux_enum,		sizeof(priv->mux_enum));
141	memcpy(&priv->mux_mux,		&simple_mux_mux,		sizeof(priv->mux_mux));
142	memcpy(&priv->mux_widgets,	&simple_mux_dapm_widgets,	sizeof(priv->mux_widgets));
143	memcpy(&priv->mux_routes,	&simple_mux_dapm_routes,	sizeof(priv->mux_routes));
144
145	priv->mux_driver.dapm_widgets		= priv->mux_widgets;
146	priv->mux_driver.num_dapm_widgets	= MUX_WIDGET_SIZE;
147	priv->mux_driver.dapm_routes		= priv->mux_routes;
148	priv->mux_driver.num_dapm_routes	= MUX_ROUTE_SIZE;
149	priv->mux_driver.read			= simple_mux_read;
150
151	/* Overwrite text ("Input 1", "Input 2") if property exists */
152	of_property_read_string_array(np, "state-labels", priv->mux_texts, MUX_TEXT_SIZE);
153
154	ret = of_property_read_u32(np, "idle-state", &priv->idle_state);
155	if (ret < 0) {
156		priv->idle_state = MUX_IDLE_AS_IS;
157	} else if (priv->idle_state != MUX_IDLE_AS_IS && priv->idle_state >= 2) {
158		dev_err(dev, "invalid idle-state %u\n", priv->idle_state);
159		return -EINVAL;
160	}
161
162	/* switch to use priv data instead of default */
163	priv->mux_enum.texts			= priv->mux_texts;
164	priv->mux_mux.private_value		= (unsigned long)&priv->mux_enum;
165	priv->mux_widgets[2].kcontrol_news	= &priv->mux_mux;
166	priv->mux_routes[1].control		= priv->mux_texts[0]; // "Input 1"
167	priv->mux_routes[2].control		= priv->mux_texts[1]; // "Input 2"
168
169	return devm_snd_soc_register_component(dev, &priv->mux_driver, NULL, 0);
170}
171
172#ifdef CONFIG_OF
173static const struct of_device_id simple_mux_ids[] = {
174	{ .compatible = "simple-audio-mux", },
175	{ }
176};
177MODULE_DEVICE_TABLE(of, simple_mux_ids);
178#endif
179
180static struct platform_driver simple_mux_driver = {
181	.driver = {
182		.name = "simple-mux",
183		.of_match_table = of_match_ptr(simple_mux_ids),
184	},
185	.probe = simple_mux_probe,
186};
187
188module_platform_driver(simple_mux_driver);
189
190MODULE_DESCRIPTION("ASoC Simple Audio Mux driver");
191MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
192MODULE_LICENSE("GPL");