ASoC: tas2764: Export 'die_temp' to sysfs

Export a file for the readout of die temperature measurements.

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>

Author: povik

sound/soc/codecs/tas2764.c

@@ -16,6 +16,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/slab.h>
+#include <linux/sysfs.h>
 #include <sound/soc.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -567,6 +568,39 @@ static int tas2764_apply_unk_apple_quirk(struct snd_soc_component *component)
 	return 0;
 }
 
+static int tas2764_read_die_temp(struct tas2764_priv *tas2764, int *result)
+{
+	int ret;
+
+	ret = snd_soc_component_read(tas2764->component, TAS2764_TEMP);
+	if (ret < 0)
+		return ret;
+	*result = ret - 93;
+	return 0;
+}
+
+static ssize_t die_temp_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct tas2764_priv *tas2764 = i2c_get_clientdata(to_i2c_client(dev));
+	int ret, temp;
+
+	ret = tas2764_read_die_temp(tas2764, &temp);
+
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d C\n", temp);
+}
+
+static DEVICE_ATTR_RO(die_temp);
+
+static struct attribute *tas2764_sysfs_attrs[] = {
+	&dev_attr_die_temp.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(tas2764_sysfs);
+
 static int tas2764_codec_probe(struct snd_soc_component *component)
 {
 	struct tas2764_priv *tas2764 = snd_soc_component_get_drvdata(component);
@@ -657,9 +691,19 @@ static int tas2764_codec_probe(struct snd_soc_component *component)
 		}
 	}
 
+	ret = sysfs_create_groups(&component->dev->kobj, tas2764_sysfs_groups);
+
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
+static void tas2764_codec_remove(struct snd_soc_component *component)
+{
+	sysfs_remove_groups(&component->dev->kobj, tas2764_sysfs_groups);
+}
+
 static DECLARE_TLV_DB_SCALE(tas2764_digital_tlv, 1100, 50, 0);
 static DECLARE_TLV_DB_SCALE(tas2764_playback_volume, -10050, 50, 1);
 
@@ -691,6 +735,7 @@ static const struct snd_kcontrol_new tas2764_snd_controls[] = {
 
 static const struct snd_soc_component_driver soc_component_driver_tas2764 = {
 	.probe			= tas2764_codec_probe,
+	.remove			= tas2764_codec_remove,
 	.suspend		= tas2764_codec_suspend,
 	.resume			= tas2764_codec_resume,
 	.controls		= tas2764_snd_controls,

sound/soc/codecs/tas2764.h

@@ -117,6 +117,9 @@
 #define TAS2764_INT_LTCH3               TAS2764_REG(0x0, 0x50)
 #define TAS2764_INT_LTCH4               TAS2764_REG(0x0, 0x51)
 
+/* Readout Registers */
+#define TAS2764_TEMP                    TAS2764_REG(0x0, 0x56)
+
 /* Clock/IRQ Settings */
 #define TAS2764_INT_CLK_CFG             TAS2764_REG(0x0, 0x5c)
 #define TAS2764_INT_CLK_CFG_IRQZ_CLR    BIT(2)