+
+/* Sysfs conventions report temperatures in millidegrees Celsius.
+ * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
+ * accuracy scheme without calibration data. For now we won't try either;
+ * userspace sees raw sensor values, and must scale/calibrate appropriately.
+ */
+static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
+{
+ return v;
+}
+
+SHOW(temp0, temp0, null_adjust) /* temp1_input */
+SHOW(temp1, temp1, null_adjust) /* temp2_input */
+
+
+/* sysfs conventions report voltages in millivolts. We can convert voltages
+ * if we know vREF. userspace may need to scale vAUX to match the board's
+ * external resistors; we assume that vBATT only uses the internal ones.
+ */
+static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
+{
+ unsigned retval = v;
+
+ /* external resistors may scale vAUX into 0..vREF */
+ retval *= ts->vref_mv;
+ retval = retval >> 12;
+ return retval;
+}
+
+static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
+{
+ unsigned retval = vaux_adjust(ts, v);
+
+ /* ads7846 has a resistor ladder to scale this signal down */
+ if (ts->model == 7846)
+ retval *= 4;
+ return retval;
+}
+
+SHOW(in0_input, vaux, vaux_adjust)
+SHOW(in1_input, vbatt, vbatt_adjust)
+
+
+static struct attribute *ads7846_attributes[] = {
+ &dev_attr_temp0.attr,
+ &dev_attr_temp1.attr,
+ &dev_attr_in0_input.attr,
+ &dev_attr_in1_input.attr,
+ NULL,
+};
+
+static struct attribute_group ads7846_attr_group = {
+ .attrs = ads7846_attributes,
+};
+
+static struct attribute *ads7843_attributes[] = {
+ &dev_attr_in0_input.attr,
+ &dev_attr_in1_input.attr,
+ NULL,
+};
+
+static struct attribute_group ads7843_attr_group = {
+ .attrs = ads7843_attributes,
+};
+
+static struct attribute *ads7845_attributes[] = {
+ &dev_attr_in0_input.attr,
+ NULL,
+};
+
+static struct attribute_group ads7845_attr_group = {
+ .attrs = ads7845_attributes,
+};
+
+static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
+{
+ struct device *hwmon;
+ int err;
+
+ /* hwmon sensors need a reference voltage */
+ switch (ts->model) {
+ case 7846:
+ if (!ts->vref_mv) {
+ dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
+ ts->vref_mv = 2500;
+ }
+ break;
+ case 7845:
+ case 7843:
+ if (!ts->vref_mv) {
+ dev_warn(&spi->dev,
+ "external vREF for ADS%d not specified\n",
+ ts->model);
+ return 0;
+ }
+ break;
+ }
+
+ /* different chips have different sensor groups */
+ switch (ts->model) {
+ case 7846:
+ ts->attr_group = &ads7846_attr_group;
+ break;
+ case 7845:
+ ts->attr_group = &ads7845_attr_group;
+ break;
+ case 7843:
+ ts->attr_group = &ads7843_attr_group;
+ break;
+ default:
+ dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
+ return 0;
+ }
+
+ err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
+ if (err)
+ return err;
+
+ hwmon = hwmon_device_register(&spi->dev);
+ if (IS_ERR(hwmon)) {
+ sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
+ return PTR_ERR(hwmon);
+ }
+
+ ts->hwmon = hwmon;
+ return 0;
+}
+
+static void ads784x_hwmon_unregister(struct spi_device *spi,
+ struct ads7846 *ts)
+{
+ if (ts->hwmon) {
+ sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
+ hwmon_device_unregister(ts->hwmon);
+ }
+}
+
+#else
+static inline int ads784x_hwmon_register(struct spi_device *spi,
+ struct ads7846 *ts)
+{
+ return 0;
+}
+
+static inline void ads784x_hwmon_unregister(struct spi_device *spi,
+ struct ads7846 *ts)
+{
+}
+#endif