ASoC: ac97: add gpio chip

The AC97 specification provides a guide for 16 GPIOs in the codecs. If
the gpiolib is compiled in the kernel, declare a gpio chip.

This was tested with a pxa27x board (mioa701) and a wm9713 codec.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

include/sound/ac97_codec.h

@@ -417,11 +417,13 @@
 #define AC97_RATES_MIC_ADC	4
 #define AC97_RATES_SPDIF	5
 
+#define AC97_NUM_GPIOS		16
 /*
  *
  */
 
 struct snd_ac97;
+struct snd_ac97_gpio_priv;
 struct snd_pcm_chmap;
 
 struct snd_ac97_build_ops {
@@ -529,6 +531,7 @@ struct snd_ac97 {
 	struct delayed_work power_work;
 #endif
 	struct device dev;
+	struct snd_ac97_gpio_priv *gpio_priv;
 
 	struct snd_pcm_chmap *chmaps[2]; /* channel-maps (optional) */
 };

sound/soc/soc-ac97.c

@@ -20,6 +20,7 @@
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/init.h>
 #include <linux/of_gpio.h>
 #include <linux/of.h>
@@ -38,6 +39,14 @@ struct snd_ac97_reset_cfg {
 	int gpio_reset;
 };
 
+struct snd_ac97_gpio_priv {
+#ifdef CONFIG_GPIOLIB
+	struct gpio_chip gpio_chip;
+#endif
+	unsigned int gpios_set;
+	struct snd_soc_codec *codec;
+};
+
 static struct snd_ac97_bus soc_ac97_bus = {
 	.ops = NULL, /* Gets initialized in snd_soc_set_ac97_ops() */
 };
@@ -47,6 +56,117 @@ static void soc_ac97_device_release(struct device *dev)
 	kfree(to_ac97_t(dev));
 }
 
+#ifdef CONFIG_GPIOLIB
+static inline struct snd_soc_codec *gpio_to_codec(struct gpio_chip *chip)
+{
+	struct snd_ac97_gpio_priv *gpio_priv =
+		container_of(chip, struct snd_ac97_gpio_priv, gpio_chip);
+
+	return gpio_priv->codec;
+}
+
+static int snd_soc_ac97_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	if (offset >= AC97_NUM_GPIOS)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int snd_soc_ac97_gpio_direction_in(struct gpio_chip *chip,
+					  unsigned offset)
+{
+	struct snd_soc_codec *codec = gpio_to_codec(chip);
+
+	dev_dbg(codec->dev, "set gpio %d to output\n", offset);
+	return snd_soc_update_bits(codec, AC97_GPIO_CFG,
+				   1 << offset, 1 << offset);
+}
+
+static int snd_soc_ac97_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct snd_soc_codec *codec = gpio_to_codec(chip);
+	int ret;
+
+	ret = snd_soc_read(codec, AC97_GPIO_STATUS);
+	dev_dbg(codec->dev, "get gpio %d : %d\n", offset,
+		ret < 0 ? ret : ret & (1 << offset));
+
+	return ret < 0 ? ret : ret & (1 << offset);
+}
+
+static void snd_soc_ac97_gpio_set(struct gpio_chip *chip, unsigned offset,
+				  int value)
+{
+	struct snd_ac97_gpio_priv *gpio_priv =
+		container_of(chip, struct snd_ac97_gpio_priv, gpio_chip);
+	struct snd_soc_codec *codec = gpio_to_codec(chip);
+
+	gpio_priv->gpios_set &= ~(1 << offset);
+	gpio_priv->gpios_set |= (!!value) << offset;
+	snd_soc_write(codec, AC97_GPIO_STATUS, gpio_priv->gpios_set);
+	dev_dbg(codec->dev, "set gpio %d to %d\n", offset, !!value);
+}
+
+static int snd_soc_ac97_gpio_direction_out(struct gpio_chip *chip,
+				     unsigned offset, int value)
+{
+	struct snd_soc_codec *codec = gpio_to_codec(chip);
+
+	dev_dbg(codec->dev, "set gpio %d to output\n", offset);
+	snd_soc_ac97_gpio_set(chip, offset, value);
+	return snd_soc_update_bits(codec, AC97_GPIO_CFG, 1 << offset, 0);
+}
+
+static struct gpio_chip snd_soc_ac97_gpio_chip = {
+	.label			= "snd_soc_ac97",
+	.owner			= THIS_MODULE,
+	.request		= snd_soc_ac97_gpio_request,
+	.direction_input	= snd_soc_ac97_gpio_direction_in,
+	.get			= snd_soc_ac97_gpio_get,
+	.direction_output	= snd_soc_ac97_gpio_direction_out,
+	.set			= snd_soc_ac97_gpio_set,
+	.can_sleep		= 1,
+};
+
+static int snd_soc_ac97_init_gpio(struct snd_ac97 *ac97,
+				  struct snd_soc_codec *codec)
+{
+	struct snd_ac97_gpio_priv *gpio_priv;
+	int ret;
+
+	gpio_priv = devm_kzalloc(codec->dev, sizeof(*gpio_priv), GFP_KERNEL);
+	if (!gpio_priv)
+		return -ENOMEM;
+	ac97->gpio_priv = gpio_priv;
+	gpio_priv->codec = codec;
+	gpio_priv->gpio_chip = snd_soc_ac97_gpio_chip;
+	gpio_priv->gpio_chip.ngpio = AC97_NUM_GPIOS;
+	gpio_priv->gpio_chip.dev = codec->dev;
+	gpio_priv->gpio_chip.base = -1;
+
+	ret = gpiochip_add(&gpio_priv->gpio_chip);
+	if (ret != 0)
+		dev_err(codec->dev, "Failed to add GPIOs: %d\n", ret);
+	return ret;
+}
+
+static void snd_soc_ac97_free_gpio(struct snd_ac97 *ac97)
+{
+	gpiochip_remove(&ac97->gpio_priv->gpio_chip);
+}
+#else
+static int snd_soc_ac97_init_gpio(struct snd_ac97 *ac97,
+				  struct snd_soc_codec *codec)
+{
+	return 0;
+}
+
+static void snd_soc_ac97_free_gpio(struct snd_ac97 *ac97)
+{
+}
+#endif
+
 /**
  * snd_soc_alloc_ac97_codec() - Allocate new a AC'97 device
  * @codec: The CODEC for which to create the AC'97 device
@@ -119,6 +239,10 @@ struct snd_ac97 *snd_soc_new_ac97_codec(struct snd_soc_codec *codec,
 	if (ret)
 		goto err_put_device;
 
+	ret = snd_soc_ac97_init_gpio(ac97, codec);
+	if (ret)
+		goto err_put_device;
+
 	return ac97;
 
 err_put_device:
@@ -135,6 +259,7 @@ EXPORT_SYMBOL_GPL(snd_soc_new_ac97_codec);
  */
 void snd_soc_free_ac97_codec(struct snd_ac97 *ac97)
 {
+	snd_soc_ac97_free_gpio(ac97);
 	device_del(&ac97->dev);
 	ac97->bus = NULL;
 	put_device(&ac97->dev);