iio: dac: ad5686: add control_sync() for single-channel devices

Create ad5310_control_sync() and ad5683_control_sync() functions that
properly consume the mask definitions with FIELD_PREP(). This allows to
reuse a function that updates the control register with cached values,
without relying on confusing logic that depends on st->use_internal_vref,
which is initialized earlier in ad5686_probe() because it is also
applicable to the AD5686_REGMAP case, removing the need for the
has_external_vref. Powerdown masks initialization is simplified as
*_control_sync() masks outs any unused bits for the single-channel case.
The change cleans up ad5686_write_dac_powerdown() and ad5686_probe(),
organizing the code for feature extension, e.g. gain control support for
single-channel devices.

Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
index 3409b551dbf74701b2abc9258de256c565a26675..86bc944a1acd9b8c8507cd9b562617b6e09e4174 100644 (file)
--- a/drivers/iio/dac/ad5686.c
+++ b/drivers/iio/dac/ad5686.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/array_size.h>
+#include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/errno.h>
 #include <linux/export.h>
@@ -13,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/sysfs.h>
+#include <linux/wordpart.h>
 
 #include <linux/iio/iio.h>
 
@@ -24,6 +26,24 @@ static const char * const ad5686_powerdown_modes[] = {
        "three_state"
 };
 
+static int ad5310_control_sync(struct ad5686_state *st)
+{
+       unsigned int pd_val = st->pwr_down_mask & st->pwr_down_mode;
+
+       return st->write(st, AD5686_CMD_CONTROL_REG, 0,
+                        FIELD_PREP(AD5310_PD_MSK, pd_val & AD5686_PD_MSK) |
+                        FIELD_PREP(AD5310_REF_BIT_MSK, st->use_internal_vref ? 0 : 1));
+}
+
+static int ad5683_control_sync(struct ad5686_state *st)
+{
+       unsigned int pd_val = st->pwr_down_mask & st->pwr_down_mode;
+
+       return st->write(st, AD5686_CMD_CONTROL_REG, 0,
+                        FIELD_PREP(AD5683_PD_MSK, pd_val & AD5686_PD_MSK) |
+                        FIELD_PREP(AD5683_REF_BIT_MSK, st->use_internal_vref ? 0 : 1));
+}
+
 static inline unsigned int ad5686_pd_mask_shift(const struct iio_chan_spec *chan)
 {
        if (chan->channel == chan->address)
@@ -98,8 +118,8 @@ static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
        bool readin;
        int ret;
        struct ad5686_state *st = iio_priv(indio_dev);
-       unsigned int val, ref_bit_msk;
-       u8 shift, address = 0;
+       unsigned int val;
+       u8 address;
 
        ret = kstrtobool(buf, &readin);
        if (ret)
@@ -114,32 +134,34 @@ static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
 
        switch (st->chip_info->regmap_type) {
        case AD5310_REGMAP:
-               shift = 9;
-               ref_bit_msk = AD5310_REF_BIT_MSK;
+               ret = ad5310_control_sync(st);
+               if (ret)
+                       return ret;
                break;
        case AD5683_REGMAP:
-               shift = 13;
-               ref_bit_msk = AD5683_REF_BIT_MSK;
+               ret = ad5683_control_sync(st);
+               if (ret)
+                       return ret;
                break;
        case AD5686_REGMAP:
-               shift = 0;
-               ref_bit_msk = 0;
                /* AD5674R/AD5679R have 16 channels and 2 powerdown registers */
-               if (chan->channel > 0x7)
+               val = st->pwr_down_mask & st->pwr_down_mode;
+               if (chan->channel > 0x7) {
                        address = 0x8;
+                       val = upper_16_bits(val);
+               } else {
+                       address = 0x0;
+                       val = lower_16_bits(val);
+               }
+               ret = st->write(st, AD5686_CMD_POWERDOWN_DAC, address, val);
+               if (ret)
+                       return ret;
                break;
        default:
                return -EINVAL;
        }
 
-       val = ((st->pwr_down_mask & st->pwr_down_mode) << shift);
-       if (!st->use_internal_vref)
-               val |= ref_bit_msk;
-
-       ret = st->write(st, AD5686_CMD_POWERDOWN_DAC,
-                       address, val >> (address * 2));
-
-       return ret ? ret : len;
+       return len;
 }
 
 static int ad5686_read_raw(struct iio_dev *indio_dev,
@@ -453,9 +475,6 @@ int ad5686_probe(struct device *dev,
 {
        struct ad5686_state *st;
        struct iio_dev *indio_dev;
-       unsigned int val, ref_bit_msk, shift;
-       bool has_external_vref;
-       u8 cmd;
        int ret, i;
 
        indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
@@ -473,13 +492,12 @@ int ad5686_probe(struct device *dev,
        if (ret < 0 && ret != -ENODEV)
                return ret;
 
-       has_external_vref = ret != -ENODEV;
-       st->vref_mv = has_external_vref ? ret / 1000 : st->chip_info->int_vref_mv;
+       st->use_internal_vref = ret == -ENODEV;
+       st->vref_mv = st->use_internal_vref ? st->chip_info->int_vref_mv : ret / 1000;
 
-       /* Initialize masks to all ones provided the max shift (last channel) */
-       shift = ad5686_pd_mask_shift(&st->chip_info->channels[st->chip_info->num_channels - 1]);
-       st->pwr_down_mask = GENMASK(shift + 1, 0);
-       st->pwr_down_mode = GENMASK(shift + 1, 0);
+       /* Initialize masks to all ones */
+       st->pwr_down_mask = ~0;
+       st->pwr_down_mode = ~0;
 
        /* Set all the power down mode for all channels to 1K pulldown */
        for (i = 0; i < st->chip_info->num_channels; i++) {
@@ -501,29 +519,25 @@ int ad5686_probe(struct device *dev,
 
        switch (st->chip_info->regmap_type) {
        case AD5310_REGMAP:
-               cmd = AD5686_CMD_CONTROL_REG;
-               ref_bit_msk = AD5310_REF_BIT_MSK;
-               st->use_internal_vref = !has_external_vref;
+               ret = ad5310_control_sync(st);
+               if (ret)
+                       return ret;
                break;
        case AD5683_REGMAP:
-               cmd = AD5686_CMD_CONTROL_REG;
-               ref_bit_msk = AD5683_REF_BIT_MSK;
-               st->use_internal_vref = !has_external_vref;
+               ret = ad5683_control_sync(st);
+               if (ret)
+                       return ret;
                break;
        case AD5686_REGMAP:
-               cmd = AD5686_CMD_INTERNAL_REFER_SETUP;
-               ref_bit_msk = AD5686_REF_BIT_MSK;
+               ret = st->write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
+                               st->use_internal_vref ? 0 : AD5686_REF_BIT_MSK);
+               if (ret)
+                       return ret;
                break;
        default:
                return -EINVAL;
        }
 
-       val = has_external_vref ? ref_bit_msk : 0;
-
-       ret = st->write(st, cmd, 0, val);
-       if (ret)
-               return ret;
-
        return devm_iio_device_register(dev, indio_dev);
 }
 EXPORT_SYMBOL_NS_GPL(ad5686_probe, "IIO_AD5686");

diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h
index 176d41966985bae75c3a2da696f9559025b21ea4..17980c54839c6aae1adadb588009dbd770cc5a26 100644 (file)
--- a/drivers/iio/dac/ad5686.h
+++ b/drivers/iio/dac/ad5686.h
@@ -39,9 +39,12 @@
 #define AD5686_CMD_READBACK_ENABLE_V2          0x5
 
 #define AD5310_REF_BIT_MSK                     BIT(8)
+#define AD5310_PD_MSK                          GENMASK(10, 9)
+
 #define AD5683_REF_BIT_MSK                     BIT(12)
-#define AD5686_REF_BIT_MSK                     BIT(0)
+#define AD5683_PD_MSK                          GENMASK(14, 13)
 
+#define AD5686_REF_BIT_MSK                     BIT(0)
 #define AD5686_PD_MSK                          GENMASK(1, 0)
 
 #define AD5686_PD_MODE_1K_TO_GND               0x1