staging: IIO: DAC: AD5446: Add power down support

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 153 insertions, 19 deletions

diff --git a/drivers/staging/iio/dac/ad5446.c b/drivers/staging/iio/dac/ad5446.c
index 4f1d8813272..861a7eacdaf 100644
--- a/drivers/staging/iio/dac/ad5446.c
+++ b/drivers/staging/iio/dac/ad5446.c
@@ -48,6 +48,20 @@ static void ad5660_store_sample(struct ad5446_state *st, unsigned val)
         st->data.d24[2] = val & 0xFF;
 }
 
+static void ad5620_store_pwr_down(struct ad5446_state *st, unsigned mode)
+{
+        st->data.d16 = cpu_to_be16(mode << 14);
+}
+
+static void ad5660_store_pwr_down(struct ad5446_state *st, unsigned mode)
+{
+        unsigned val = mode << 16;
+
+        st->data.d24[0] = (val >> 16) & 0xFF;
+        st->data.d24[1] = (val >> 8) & 0xFF;
+        st->data.d24[2] = val & 0xFF;
+}
+
 static ssize_t ad5446_write(struct device *dev,
                 struct device_attribute *attr,
                 const char *buf,
@@ -68,6 +82,7 @@ static ssize_t ad5446_write(struct device *dev,
         }
 
         mutex_lock(&dev_info->mlock);
+        st->cached_val = val;
         st->chip_info->store_sample(st, val);
         ret = spi_sync(st->spi, &st->msg);
         mutex_unlock(&dev_info->mlock);
@@ -102,15 +117,119 @@ static ssize_t ad5446_show_name(struct device *dev,
 }
 static IIO_DEVICE_ATTR(name, S_IRUGO, ad5446_show_name, NULL, 0);
 
+static ssize_t ad5446_write_powerdown_mode(struct device *dev,
+                                       struct device_attribute *attr,
+                                       const char *buf, size_t len)
+{
+        struct iio_dev *dev_info = dev_get_drvdata(dev);
+        struct ad5446_state *st = dev_info->dev_data;
+
+        if (sysfs_streq(buf, "1kohm_to_gnd"))
+                st->pwr_down_mode = MODE_PWRDWN_1k;
+        else if (sysfs_streq(buf, "100kohm_to_gnd"))
+                st->pwr_down_mode = MODE_PWRDWN_100k;
+        else if (sysfs_streq(buf, "three_state"))
+                st->pwr_down_mode = MODE_PWRDWN_TRISTATE;
+        else
+                return -EINVAL;
+
+        return len;
+}
+
+static ssize_t ad5446_read_powerdown_mode(struct device *dev,
+                                      struct device_attribute *attr, char *buf)
+{
+        struct iio_dev *dev_info = dev_get_drvdata(dev);
+        struct ad5446_state *st = dev_info->dev_data;
+
+        char mode[][15] = {"", "1kohm_to_gnd", "100kohm_to_gnd", "three_state"};
+
+        return sprintf(buf, "%s\n", mode[st->pwr_down_mode]);
+}
+
+static ssize_t ad5446_read_dac_powerdown(struct device *dev,
+                                           struct device_attribute *attr,
+                                           char *buf)
+{
+        struct iio_dev *dev_info = dev_get_drvdata(dev);
+        struct ad5446_state *st = dev_info->dev_data;
+
+        return sprintf(buf, "%d\n", st->pwr_down);
+}
+
+static ssize_t ad5446_write_dac_powerdown(struct device *dev,
+                                            struct device_attribute *attr,
+                                            const char *buf, size_t len)
+{
+        struct iio_dev *dev_info = dev_get_drvdata(dev);
+        struct ad5446_state *st = dev_info->dev_data;
+        unsigned long readin;
+        int ret;
+
+        ret = strict_strtol(buf, 10, &readin);
+        if (ret)
+                return ret;
+
+        if (readin > 1)
+                ret = -EINVAL;
+
+        mutex_lock(&dev_info->mlock);
+        st->pwr_down = readin;
+
+        if (st->pwr_down)
+                st->chip_info->store_pwr_down(st, st->pwr_down_mode);
+        else
+                st->chip_info->store_sample(st, st->cached_val);
+
+        ret = spi_sync(st->spi, &st->msg);
+        mutex_unlock(&dev_info->mlock);
+
+        return ret ? ret : len;
+}
+
+static IIO_DEVICE_ATTR(out_powerdown_mode, S_IRUGO | S_IWUSR,
+                        ad5446_read_powerdown_mode,
+                        ad5446_write_powerdown_mode, 0);
+
+static IIO_CONST_ATTR(out_powerdown_mode_available,
+                        "1kohm_to_gnd 100kohm_to_gnd three_state");
+
+static IIO_DEVICE_ATTR(out0_powerdown, S_IRUGO | S_IWUSR,
+                        ad5446_read_dac_powerdown,
+                        ad5446_write_dac_powerdown, 0);
+
 static struct attribute *ad5446_attributes[] = {
         &iio_dev_attr_out0_raw.dev_attr.attr,
         &iio_dev_attr_out_scale.dev_attr.attr,
+        &iio_dev_attr_out0_powerdown.dev_attr.attr,
+        &iio_dev_attr_out_powerdown_mode.dev_attr.attr,
+        &iio_const_attr_out_powerdown_mode_available.dev_attr.attr,
         &iio_dev_attr_name.dev_attr.attr,
         NULL,
 };
 
+static mode_t ad5446_attr_is_visible(struct kobject *kobj,
+                                     struct attribute *attr, int n)
+{
+        struct device *dev = container_of(kobj, struct device, kobj);
+        struct iio_dev *dev_info = dev_get_drvdata(dev);
+        struct ad5446_state *st = iio_dev_get_devdata(dev_info);
+
+        mode_t mode = attr->mode;
+
+        if (!st->chip_info->store_pwr_down &&
+                (attr == &iio_dev_attr_out0_powerdown.dev_attr.attr ||
+                attr == &iio_dev_attr_out_powerdown_mode.dev_attr.attr ||
+                attr ==
+                &iio_const_attr_out_powerdown_mode_available.dev_attr.attr))
+                mode = 0;
+
+        return mode;
+}
+
 static const struct attribute_group ad5446_attribute_group = {
         .attrs = ad5446_attributes,
+        .is_visible = ad5446_attr_is_visible,
 };
 
 static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
@@ -156,6 +275,7 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
                 .left_shift = 2,
                 .int_vref_mv = 2500,
                 .store_sample = ad5620_store_sample,
+                .store_pwr_down = ad5620_store_pwr_down,
         },
         [ID_AD5620_1250] = {
                 .bits = 12,
@@ -163,6 +283,7 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
                 .left_shift = 2,
                 .int_vref_mv = 1250,
                 .store_sample = ad5620_store_sample,
+                .store_pwr_down = ad5620_store_pwr_down,
         },
         [ID_AD5640_2500] = {
                 .bits = 14,
@@ -170,6 +291,7 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
                 .left_shift = 0,
                 .int_vref_mv = 2500,
                 .store_sample = ad5620_store_sample,
+                .store_pwr_down = ad5620_store_pwr_down,
         },
         [ID_AD5640_1250] = {
                 .bits = 14,
@@ -177,6 +299,7 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
                 .left_shift = 0,
                 .int_vref_mv = 1250,
                 .store_sample = ad5620_store_sample,
+                .store_pwr_down = ad5620_store_pwr_down,
         },
         [ID_AD5660_2500] = {
                 .bits = 16,
@@ -184,6 +307,7 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
                 .left_shift = 0,
                 .int_vref_mv = 2500,
                 .store_sample = ad5660_store_sample,
+                .store_pwr_down = ad5660_store_pwr_down,
         },
         [ID_AD5660_1250] = {
                 .bits = 16,
@@ -191,6 +315,7 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
                 .left_shift = 0,
                 .int_vref_mv = 1250,
                 .store_sample = ad5660_store_sample,
+                .store_pwr_down = ad5660_store_pwr_down,
         },
 };
 
@@ -243,20 +368,20 @@ static int __devinit ad5446_probe(struct spi_device *spi)
         spi_message_add_tail(&st->xfer, &st->msg);
 
         switch (spi_get_device_id(spi)->driver_data) {
-                case ID_AD5620_2500:
-                case ID_AD5620_1250:
-                case ID_AD5640_2500:
-                case ID_AD5640_1250:
-                case ID_AD5660_2500:
-                case ID_AD5660_1250:
-                        st->vref_mv = st->chip_info->int_vref_mv;
-                        break;
-                default:
-                        if (voltage_uv)
-                                st->vref_mv = voltage_uv / 1000;
-                        else
-                                dev_warn(&spi->dev,
-                                         "reference voltage unspecified\n");
+        case ID_AD5620_2500:
+        case ID_AD5620_1250:
+        case ID_AD5640_2500:
+        case ID_AD5640_1250:
+        case ID_AD5660_2500:
+        case ID_AD5660_1250:
+                st->vref_mv = st->chip_info->int_vref_mv;
+                break;
+        default:
+                if (voltage_uv)
+                        st->vref_mv = voltage_uv / 1000;
+                else
+                        dev_warn(&spi->dev,
+                                 "reference voltage unspecified\n");
         }
 
         ret = iio_device_register(st->indio_dev);
diff --git a/drivers/staging/iio/dac/ad5446.h b/drivers/staging/iio/dac/ad5446.h
index 0cb9c14279e..e9397a6783c 100644
--- a/drivers/staging/iio/dac/ad5446.h
+++ b/drivers/staging/iio/dac/ad5446.h
@@ -27,6 +27,10 @@
 
 #define RES_MASK(bits)  ((1 << (bits)) - 1)
 
+#define MODE_PWRDWN_1k          0x1
+#define MODE_PWRDWN_100k        0x2
+#define MODE_PWRDWN_TRISTATE    0x3
+
 /**
  * struct ad5446_state - driver instance specific data
  * @indio_dev:          the industrial I/O device
@@ -47,6 +51,9 @@ struct ad5446_state {
         struct regulator                *reg;
         struct work_struct              poll_work;
         unsigned short                  vref_mv;
+        unsigned                        cached_val;
+        unsigned                        pwr_down_mode;
+        unsigned                        pwr_down;
         struct spi_transfer             xfer;
         struct spi_message              msg;
         union {
@@ -62,14 +69,16 @@ struct ad5446_state {
  * @left_shift:         number of bits the datum must be shifted
  * @int_vref_mv:        AD5620/40/60: the internal reference voltage
  * @store_sample:       chip specific helper function to store the datum
+ * @store_sample:       chip specific helper function to store the powerpown cmd
  */
 
 struct ad5446_chip_info {
-        u8                              bits;
-        u8                              storagebits;
-        u8                              left_shift;
-        u16                             int_vref_mv;
-        void (*store_sample)            (struct ad5446_state *st, unsigned val);
+        u8                      bits;
+        u8                      storagebits;
+        u8                      left_shift;
+        u16                     int_vref_mv;
+        void (*store_sample)    (struct ad5446_state *st, unsigned val);
+        void (*store_pwr_down)  (struct ad5446_state *st, unsigned mode);
 };
 
 /**