[PATCH 11/27] ASoC: tas2770: Export 'die_temp' to sysfs

[James Calligeros <jcalligeros99@gmail.com>]

From: Martin Povišer <povik+lin@cutebit.org>

Export a file for the readout of die temperature measurements.
As per the datasheet, the temperature can be calculated by
dividing the register value by 16 and then subtracting 93.

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
---
 sound/soc/codecs/tas2770.c | 57 +++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/sound/soc/codecs/tas2770.c b/sound/soc/codecs/tas2770.c
index 35a4d5a4a3e0cf4f71f81fd59f44f075c59cdbc1..9f3588ec117bb8ed0a6f2bbe5d7dc422862f052b 100644
--- a/sound/soc/codecs/tas2770.c
+++ b/sound/soc/codecs/tas2770.c
@@ -20,6 +20,7 @@
 #include <linux/regmap.h>
 #include <linux/of.h>
 #include <linux/slab.h>
+#include <linux/sysfs.h>
 #include <sound/soc.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -491,6 +492,51 @@ static struct snd_soc_dai_driver tas2770_dai_driver[] = {
 	},
 };
 
+static int tas2770_read_die_temp(struct tas2770_priv *tas2770, int *result)
+{
+	int ret, reading;
+
+	ret = snd_soc_component_read(tas2770->component, TAS2770_TEMP_MSB);
+	if (ret < 0)
+		return ret;
+	reading = ret << 4;
+
+	ret = snd_soc_component_read(tas2770->component, TAS2770_TEMP_LSB);
+	if (ret < 0)
+		return ret;
+	reading |= ret >> 4;
+
+	/*
+	 * As per datasheet: divide register by 16 and subtract 93. We don't
+	 * want to divide just yet though.
+	 */
+	*result = reading - (93 * 16);
+	return 0;
+}
+
+static ssize_t die_temp_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct tas2770_priv *tas2770 = i2c_get_clientdata(to_i2c_client(dev));
+	int ret, temp;
+
+	ret = tas2770_read_die_temp(tas2770, &temp);
+
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d.%03d C\n", temp / 16,
+			  (temp * 1000 / 16) % 1000);
+}
+
+static DEVICE_ATTR_RO(die_temp);
+
+static struct attribute *tas2770_sysfs_attrs[] = {
+	&dev_attr_die_temp.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(tas2770_sysfs);
+
 static const struct regmap_config tas2770_i2c_regmap;
 
 static int tas2770_codec_probe(struct snd_soc_component *component)
@@ -517,9 +563,19 @@ static int tas2770_codec_probe(struct snd_soc_component *component)
 			return ret;
 	}
 
+	ret = sysfs_create_groups(&component->dev->kobj, tas2770_sysfs_groups);
+
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
+static void tas2770_codec_remove(struct snd_soc_component *component)
+{
+	sysfs_remove_groups(&component->dev->kobj, tas2770_sysfs_groups);
+}
+
 static DECLARE_TLV_DB_SCALE(tas2770_digital_tlv, 1100, 50, 0);
 static DECLARE_TLV_DB_SCALE(tas2770_playback_volume, -12750, 50, 0);
 
@@ -532,6 +588,7 @@ static const struct snd_kcontrol_new tas2770_snd_controls[] = {
 
 static const struct snd_soc_component_driver soc_component_driver_tas2770 = {
 	.probe			= tas2770_codec_probe,
+	.remove			= tas2770_codec_remove,
 	.suspend		= tas2770_codec_suspend,
 	.resume			= tas2770_codec_resume,
 	.controls		= tas2770_snd_controls,

-- 
2.48.1