iio: adc: ad7606: Move oversampling options in chip info and rework *_avail attributes

Available oversampling ratios and scales can be shown by calling a
common ad7606_show_avail function which takes as parameters the array
which stores the values, together with the size of the array.

Oversampling options are now defined in chip info
structure and they are loaded at probe.

Has_Oversampling attribute was removed because oversampling_num was added
and it is not needed anymore.

The purpose of this patch is to deal with the scale_avail and
oversampling_avail arrays in a generic way. This makes it easier to add
support for new devices which will work with different scales and
oversampling ratios. It is also an intermediate step for adding support
for ad7616 which has different oversampling sampling ratios available.
Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7606.c

@@ -31,7 +31,7 @@
  * Scales are computed as 5000/32768 and 10000/32768 respectively,
  * so that when applied to the raw values they provide mV values
  */
-static const unsigned int scale_avail[2] = {
+static const unsigned int ad7606_scale_avail[2] = {
 	152588, 305176
 };
 
@@ -154,7 +154,7 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 0;
-		*val2 = scale_avail[st->range];
+		*val2 = st->scale_avail[st->range];
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 		*val = st->oversampling;
@@ -163,21 +163,31 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
-static ssize_t in_voltage_scale_available_show(struct device *dev,
-					       struct device_attribute *attr,
-					       char *buf)
+static ssize_t ad7606_show_avail(char *buf, const unsigned int *vals,
+				 unsigned int n, bool micros)
 {
-	int i, len = 0;
-
-	for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
-		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06u ",
-				 scale_avail[i]);
+	size_t len = 0;
+	int i;
 
+	for (i = 0; i < n; i++) {
+		len += scnprintf(buf + len, PAGE_SIZE - len,
+			micros ? "0.%06u " : "%u ", vals[i]);
+	}
 	buf[len - 1] = '\n';
 
 	return len;
 }
 
+static ssize_t in_voltage_scale_available_show(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	return ad7606_show_avail(buf, st->scale_avail, st->num_scales, true);
+}
+
 static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
 
 static int ad7606_write_raw(struct iio_dev *indio_dev,
@@ -193,7 +203,7 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
 		mutex_lock(&st->lock);
-		i = find_closest(val2, scale_avail, ARRAY_SIZE(scale_avail));
+		i = find_closest(val2, st->scale_avail, st->num_scales);
 		gpiod_set_value(st->gpio_range, i);
 		st->range = i;
 		mutex_unlock(&st->lock);
@@ -202,15 +212,15 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 		if (val2)
 			return -EINVAL;
-		i = find_closest(val, ad7606_oversampling_avail,
-				 ARRAY_SIZE(ad7606_oversampling_avail));
+		i = find_closest(val, st->oversampling_avail,
+				 st->num_os_ratios);
 
 		values[0] = i;
 
 		mutex_lock(&st->lock);
 		gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,
 				      st->gpio_os->info, values);
-		st->oversampling = ad7606_oversampling_avail[i];
+		st->oversampling = st->oversampling_avail[i];
 		mutex_unlock(&st->lock);
 
 		return 0;
@@ -219,11 +229,23 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
-static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");
+static ssize_t ad7606_oversampling_ratio_avail(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	return ad7606_show_avail(buf, st->oversampling_avail,
+				 st->num_os_ratios, false);
+}
+
+static IIO_DEVICE_ATTR(oversampling_ratio_available, 0444,
+		       ad7606_oversampling_ratio_avail, NULL, 0);
 
 static struct attribute *ad7606_attributes_os_and_range[] = {
 	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
-	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
+	&iio_dev_attr_oversampling_ratio_available.dev_attr.attr,
 	NULL,
 };
 
@@ -232,7 +254,7 @@ static const struct attribute_group ad7606_attribute_group_os_and_range = {
 };
 
 static struct attribute *ad7606_attributes_os[] = {
-	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
+	&iio_dev_attr_oversampling_ratio_available.dev_attr.attr,
 	NULL,
 };
 
@@ -301,17 +323,20 @@ static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
 	[ID_AD7606_8] = {
 		.channels = ad7606_channels,
 		.num_channels = 9,
-		.has_oversampling = true,
+		.oversampling_avail = ad7606_oversampling_avail,
+		.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	},
 	[ID_AD7606_6] = {
 		.channels = ad7606_channels,
 		.num_channels = 7,
-		.has_oversampling = true,
+		.oversampling_avail = ad7606_oversampling_avail,
+		.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	},
 	[ID_AD7606_4] = {
 		.channels = ad7606_channels,
 		.num_channels = 5,
-		.has_oversampling = true,
+		.oversampling_avail = ad7606_oversampling_avail,
+		.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	},
 };
 
@@ -343,7 +368,7 @@ static int ad7606_request_gpios(struct ad7606_state *st)
 	if (IS_ERR(st->gpio_frstdata))
 		return PTR_ERR(st->gpio_frstdata);
 
-	if (!st->chip_info->has_oversampling)
+	if (!st->chip_info->oversampling_num)
 		return 0;
 
 	st->gpio_os = devm_gpiod_get_array_optional(dev,
@@ -467,6 +492,8 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 	/* tied to logic low, analog input range is +/- 5V */
 	st->range = 0;
 	st->oversampling = 1;
+	st->scale_avail = ad7606_scale_avail;
+	st->num_scales = ARRAY_SIZE(ad7606_scale_avail);
 
 	st->reg = devm_regulator_get(dev, "avcc");
 	if (IS_ERR(st->reg))
@@ -484,6 +511,11 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 
 	st->chip_info = &ad7606_chip_info_tbl[id];
 
+	if (st->chip_info->oversampling_num) {
+		st->oversampling_avail = st->chip_info->oversampling_avail;
+		st->num_os_ratios = st->chip_info->oversampling_num;
+	}
+
 	ret = ad7606_request_gpios(st);
 	if (ret)
 		return ret;

drivers/iio/adc/ad7606.h

@@ -12,12 +12,15 @@
  * struct ad7606_chip_info - chip specific information
  * @channels:		channel specification
  * @num_channels:	number of channels
- * @has_oversampling:   whether the device has oversampling support
+ * @oversampling_avail	pointer to the array which stores the available
+ *			oversampling ratios.
+ * @oversampling_num	number of elements stored in oversampling_avail array
  */
 struct ad7606_chip_info {
 	const struct iio_chan_spec	*channels;
 	unsigned int			num_channels;
-	bool				has_oversampling;
+	const unsigned int		*oversampling_avail;
+	unsigned int			oversampling_num;
 };
 
 /**
@@ -29,6 +32,11 @@ struct ad7606_chip_info {
  * @range		voltage range selection, selects which scale to apply
  * @oversampling	oversampling selection
  * @base_address	address from where to read data in parallel operation
+ * @scale_avail		pointer to the array which stores the available scales
+ * @num_scales		number of elements stored in the scale_avail array
+ * @oversampling_avail	pointer to the array which stores the available
+ *			oversampling ratios.
+ * @num_os_ratios	number of elements stored in oversampling_avail array
  * @lock		protect sensor state from concurrent accesses to GPIOs
  * @gpio_convst	GPIO descriptor for conversion start signal (CONVST)
  * @gpio_reset		GPIO descriptor for device hard-reset
@@ -50,6 +58,10 @@ struct ad7606_state {
 	unsigned int			range;
 	unsigned int			oversampling;
 	void __iomem			*base_address;
+	const unsigned int		*scale_avail;
+	unsigned int			num_scales;
+	const unsigned int		*oversampling_avail;
+	unsigned int			num_os_ratios;
 
 	struct mutex			lock; /* protect sensor state */
 	struct gpio_desc		*gpio_convst;