iio: adc: ti-ads8688: use read_avail for available attributes

Convert the in_voltage_scale_available and in_voltage_offset_available
attributes from legacy IIO_DEVICE_ATTR with custom show functions to the
IIO framework's read_avail callback. This uses the framework's built-in
support for _available attributes, removing the need for manual sysfs
formatting.

Precompute the available scale values at probe time since they depend on
the reference voltage which does not change after initialization.

Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Gabriel Rondon <grondon@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ti-ads8688.c b/drivers/iio/adc/ti-ads8688.c
index b0bf46cae0b69eb1fe8d7734c8a32ac642c5d0cd..ebd2826a7ff6a0d31b37861caddc2f40b070d9ce 100644 (file)
--- a/drivers/iio/adc/ti-ads8688.c
+++ b/drivers/iio/adc/ti-ads8688.c
@@ -6,7 +6,6 @@
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
-#include <linux/sysfs.h>
 #include <linux/spi/spi.h>
 #include <linux/regulator/consumer.h>
 #include <linux/err.h>
@@ -17,7 +16,6 @@
 #include <linux/iio/buffer.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
-#include <linux/iio/sysfs.h>
 
 #define ADS8688_CMD_REG(x)             (x << 8)
 #define ADS8688_CMD_REG_NOOP           0x00
@@ -66,6 +64,7 @@ struct ads8688_state {
        const struct ads8688_chip_info  *chip_info;
        struct spi_device               *spi;
        unsigned int                    vref_mv;
+       int                             scale_avail[3][2];
        enum ads8688_range              range[8];
        union {
                __be32 d32;
@@ -114,37 +113,9 @@ static const struct ads8688_ranges ads8688_range_def[5] = {
        }
 };
 
-static ssize_t ads8688_show_scales(struct device *dev,
-                                  struct device_attribute *attr, char *buf)
-{
-       struct ads8688_state *st = iio_priv(dev_to_iio_dev(dev));
-
-       return sprintf(buf, "0.%09u 0.%09u 0.%09u\n",
-                      ads8688_range_def[0].scale * st->vref_mv,
-                      ads8688_range_def[1].scale * st->vref_mv,
-                      ads8688_range_def[2].scale * st->vref_mv);
-}
-
-static ssize_t ads8688_show_offsets(struct device *dev,
-                                   struct device_attribute *attr, char *buf)
-{
-       return sprintf(buf, "%d %d\n", ads8688_range_def[0].offset,
-                      ads8688_range_def[3].offset);
-}
-
-static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
-                      ads8688_show_scales, NULL, 0);
-static IIO_DEVICE_ATTR(in_voltage_offset_available, S_IRUGO,
-                      ads8688_show_offsets, NULL, 0);
-
-static struct attribute *ads8688_attributes[] = {
-       &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
-       &iio_dev_attr_in_voltage_offset_available.dev_attr.attr,
-       NULL,
-};
-
-static const struct attribute_group ads8688_attribute_group = {
-       .attrs = ads8688_attributes,
+static const int ads8688_offset_avail[] = {
+       -(1 << (ADS8688_REALBITS - 1)),
+       0
 };
 
 #define ADS8688_CHAN(index)                                    \
@@ -155,6 +126,9 @@ static const struct attribute_group ads8688_attribute_group = {
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW)            \
                              | BIT(IIO_CHAN_INFO_SCALE)        \
                              | BIT(IIO_CHAN_INFO_OFFSET),      \
+       .info_mask_shared_by_type_available =                   \
+                             BIT(IIO_CHAN_INFO_SCALE)          \
+                             | BIT(IIO_CHAN_INFO_OFFSET),      \
        .scan_index = index,                                    \
        .scan_type = {                                          \
                .sign = 'u',                                    \
@@ -369,11 +343,34 @@ static int ads8688_write_raw_get_fmt(struct iio_dev *indio_dev,
        return -EINVAL;
 }
 
+static int ads8688_read_avail(struct iio_dev *indio_dev,
+                             struct iio_chan_spec const *chan,
+                             const int **vals, int *type, int *length,
+                             long mask)
+{
+       struct ads8688_state *st = iio_priv(indio_dev);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_SCALE:
+               *vals = (const int *)st->scale_avail;
+               *type = IIO_VAL_INT_PLUS_NANO;
+               *length = ARRAY_SIZE(st->scale_avail) * 2;
+               return IIO_AVAIL_LIST;
+       case IIO_CHAN_INFO_OFFSET:
+               *vals = ads8688_offset_avail;
+               *type = IIO_VAL_INT;
+               *length = ARRAY_SIZE(ads8688_offset_avail);
+               return IIO_AVAIL_LIST;
+       default:
+               return -EINVAL;
+       }
+}
+
 static const struct iio_info ads8688_info = {
        .read_raw = &ads8688_read_raw,
+       .read_avail = &ads8688_read_avail,
        .write_raw = &ads8688_write_raw,
        .write_raw_get_fmt = &ads8688_write_raw_get_fmt,
-       .attrs = &ads8688_attribute_group,
 };
 
 static irqreturn_t ads8688_trigger_handler(int irq, void *p)
@@ -426,6 +423,11 @@ static int ads8688_probe(struct spi_device *spi)
 
        st->vref_mv = ret == -ENODEV ? ADS8688_VREF_MV : ret / 1000;
 
+       for (unsigned int i = 0; i < ARRAY_SIZE(st->scale_avail); i++) {
+               st->scale_avail[i][0] = 0;
+               st->scale_avail[i][1] = ads8688_range_def[i].scale * st->vref_mv;
+       }
+
        st->chip_info = &ads8688_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 
        spi->mode = SPI_MODE_1;