iio/adc: (max1363) Add support for external reference voltage

Implement external reference voltage as regulator named "vref". Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio/adc: (max1363) Add support for external reference voltage
Implement external reference voltage as regulator named "vref". Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Guenter Roeck · Jonathan Cameron
1 parent 7c3e8675f3
Showing 1 changed file with 39 additions and 13 deletions Side-by-side Diff
drivers/iio/adc/max1363.c
@@ -163,6 +163,8 @@
  * @mask_low:		bitmask for enabled low thresholds
  * @thresh_high:	high threshold values
  * @thresh_low:		low threshold values
+ * @vref:		Reference voltage regulator
+ * @vref_uv:		Actual (external or internal) reference voltage
  */
 struct max1363_state {
 	struct i2c_client		*client;
@@ -182,6 +184,8 @@
 	/* 4x unipolar first then the fours bipolar ones */
 	s16				thresh_high[8];
 	s16				thresh_low[8];
+	struct regulator		*vref;
+	u32				vref_uv;
 };
  
 #define MAX1363_MODE_SINGLE(_num, _mask) {				\
@@ -393,6 +397,8 @@
 {
 	struct max1363_state *st = iio_priv(indio_dev);
 	int ret;
+	unsigned long scale_uv;
+
 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		ret = max1363_read_single_chan(indio_dev, chan, val, m);
@@ -400,16 +406,10 @@
 			return ret;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
-		if ((1 << (st->chip_info->bits + 1)) >
-		    st->chip_info->int_vref_mv) {
-			*val = 0;
-			*val2 = 500000;
-			return IIO_VAL_INT_PLUS_MICRO;
-		} else {
-			*val = (st->chip_info->int_vref_mv)
-				>> st->chip_info->bits;
-			return IIO_VAL_INT;
-		}
+		scale_uv = st->vref_uv >> st->chip_info->bits;
+		*val = scale_uv / 1000;
+		*val2 = (scale_uv % 1000) * 1000;
+		return IIO_VAL_INT_PLUS_MICRO;
 	default:
 		return -EINVAL;
 	}
  
@@ -1390,12 +1390,16 @@
  
 static int max1363_initial_setup(struct max1363_state *st)
 {
-	st->setupbyte = MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_VDD
-		| MAX1363_SETUP_POWER_UP_INT_REF
-		| MAX1363_SETUP_INT_CLOCK
+	st->setupbyte = MAX1363_SETUP_INT_CLOCK
 		| MAX1363_SETUP_UNIPOLAR
 		| MAX1363_SETUP_NORESET;
  
+	if (st->vref)
+		st->setupbyte |= MAX1363_SETUP_AIN3_IS_REF_EXT_TO_REF;
+	else
+		st->setupbyte |= MAX1363_SETUP_POWER_UP_INT_REF
+		  | MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_INT;
+
 	/* Set scan mode writes the config anyway so wait until then */
 	st->setupbyte = MAX1363_SETUP_BYTE(st->setupbyte);
 	st->current_mode = &max1363_mode_table[st->chip_info->default_mode];
@@ -1491,6 +1495,7 @@
 	int ret;
 	struct max1363_state *st;
 	struct iio_dev *indio_dev;
+	struct regulator *vref;
  
 	indio_dev = iio_device_alloc(sizeof(struct max1363_state));
 	if (indio_dev == NULL) {
@@ -1521,6 +1526,23 @@
 	st->chip_info = &max1363_chip_info_tbl[id->driver_data];
 	st->client = client;
  
+	st->vref_uv = st->chip_info->int_vref_mv * 1000;
+	vref = devm_regulator_get(&client->dev, "vref");
+	if (!IS_ERR(vref)) {
+		int vref_uv;
+
+		ret = regulator_enable(vref);
+		if (ret)
+			goto error_disable_reg;
+		st->vref = vref;
+		vref_uv = regulator_get_voltage(vref);
+		if (vref_uv <= 0) {
+			ret = -EINVAL;
+			goto error_disable_reg;
+		}
+		st->vref_uv = vref_uv;
+	}
+
 	ret = max1363_alloc_scan_masks(indio_dev);
 	if (ret)
 		goto error_disable_reg;
@@ -1562,6 +1584,8 @@
 error_uninit_buffer:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_disable_reg:
+	if (st->vref)
+		regulator_disable(st->vref);
 	regulator_disable(st->reg);
 error_unregister_map:
 	iio_map_array_unregister(indio_dev);
@@ -1578,6 +1602,8 @@
  
 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
+	if (st->vref)
+		regulator_disable(st->vref);
 	regulator_disable(st->reg);
 	iio_map_array_unregister(indio_dev);
 	iio_device_free(indio_dev);
...	...	@@ -163,6 +163,8 @@
163	163	* @mask_low: bitmask for enabled low thresholds
164	164	* @thresh_high: high threshold values
165	165	* @thresh_low: low threshold values
	166	+ * @vref: Reference voltage regulator
	167	+ * @vref_uv: Actual (external or internal) reference voltage
166	168	*/
167	169	struct max1363_state {
168	170	struct i2c_client *client;
...	...	@@ -182,6 +184,8 @@
182	184	/* 4x unipolar first then the fours bipolar ones */
183	185	s16 thresh_high[8];
184	186	s16 thresh_low[8];
	187	+ struct regulator *vref;
	188	+ u32 vref_uv;
185	189	};
186	190
187	191	#define MAX1363_MODE_SINGLE(_num, _mask) { \
...	...	@@ -393,6 +397,8 @@
393	397	{
394	398	struct max1363_state *st = iio_priv(indio_dev);
395	399	int ret;
	400	+ unsigned long scale_uv;
	401	+
396	402	switch (m) {
397	403	case IIO_CHAN_INFO_RAW:
398	404	ret = max1363_read_single_chan(indio_dev, chan, val, m);
...	...	@@ -400,16 +406,10 @@
400	406	return ret;
401	407	return IIO_VAL_INT;
402	408	case IIO_CHAN_INFO_SCALE:
403		- if ((1 << (st->chip_info->bits + 1)) >
404		- st->chip_info->int_vref_mv) {
405		- *val = 0;
406		- *val2 = 500000;
407		- return IIO_VAL_INT_PLUS_MICRO;
408		- } else {
409		- *val = (st->chip_info->int_vref_mv)
410		- >> st->chip_info->bits;
411		- return IIO_VAL_INT;
412		- }
	409	+ scale_uv = st->vref_uv >> st->chip_info->bits;
	410	+ *val = scale_uv / 1000;
	411	+ val2 = (scale_uv % 1000) 1000;
	412	+ return IIO_VAL_INT_PLUS_MICRO;
413	413	default:
414	414	return -EINVAL;
415	415	}
416	416
...	...	@@ -1390,12 +1390,16 @@
1390	1390
1391	1391	static int max1363_initial_setup(struct max1363_state *st)
1392	1392	{
1393		- st->setupbyte = MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_VDD
1394		- \| MAX1363_SETUP_POWER_UP_INT_REF
1395		- \| MAX1363_SETUP_INT_CLOCK
	1393	+ st->setupbyte = MAX1363_SETUP_INT_CLOCK
1396	1394	\| MAX1363_SETUP_UNIPOLAR
1397	1395	\| MAX1363_SETUP_NORESET;
1398	1396
	1397	+ if (st->vref)
	1398	+ st->setupbyte \|= MAX1363_SETUP_AIN3_IS_REF_EXT_TO_REF;
	1399	+ else
	1400	+ st->setupbyte \|= MAX1363_SETUP_POWER_UP_INT_REF
	1401	+ \| MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_INT;
	1402	+
1399	1403	/* Set scan mode writes the config anyway so wait until then */
1400	1404	st->setupbyte = MAX1363_SETUP_BYTE(st->setupbyte);
1401	1405	st->current_mode = &max1363_mode_table[st->chip_info->default_mode];
...	...	@@ -1491,6 +1495,7 @@
1491	1495	int ret;
1492	1496	struct max1363_state *st;
1493	1497	struct iio_dev *indio_dev;
	1498	+ struct regulator *vref;
1494	1499
1495	1500	indio_dev = iio_device_alloc(sizeof(struct max1363_state));
1496	1501	if (indio_dev == NULL) {
...	...	@@ -1521,6 +1526,23 @@
1521	1526	st->chip_info = &max1363_chip_info_tbl[id->driver_data];
1522	1527	st->client = client;
1523	1528
	1529	+ st->vref_uv = st->chip_info->int_vref_mv * 1000;
	1530	+ vref = devm_regulator_get(&client->dev, "vref");
	1531	+ if (!IS_ERR(vref)) {
	1532	+ int vref_uv;
	1533	+
	1534	+ ret = regulator_enable(vref);
	1535	+ if (ret)
	1536	+ goto error_disable_reg;
	1537	+ st->vref = vref;
	1538	+ vref_uv = regulator_get_voltage(vref);
	1539	+ if (vref_uv <= 0) {
	1540	+ ret = -EINVAL;
	1541	+ goto error_disable_reg;
	1542	+ }
	1543	+ st->vref_uv = vref_uv;
	1544	+ }
	1545	+
1524	1546	ret = max1363_alloc_scan_masks(indio_dev);
1525	1547	if (ret)
1526	1548	goto error_disable_reg;
...	...	@@ -1562,6 +1584,8 @@
1562	1584	error_uninit_buffer:
1563	1585	iio_triggered_buffer_cleanup(indio_dev);
1564	1586	error_disable_reg:
	1587	+ if (st->vref)
	1588	+ regulator_disable(st->vref);
1565	1589	regulator_disable(st->reg);
1566	1590	error_unregister_map:
1567	1591	iio_map_array_unregister(indio_dev);
...	...	@@ -1578,6 +1602,8 @@
1578	1602
1579	1603	iio_device_unregister(indio_dev);
1580	1604	iio_triggered_buffer_cleanup(indio_dev);
	1605	+ if (st->vref)
	1606	+ regulator_disable(st->vref);
1581	1607	regulator_disable(st->reg);
1582	1608	iio_map_array_unregister(indio_dev);
1583	1609	iio_device_free(indio_dev);