[PATCH 3/5] max44000: Support controlling LED current output

[Crestez Dan Leonard]

This is exposed as an output channel with "led" as an extend_name.

Other sensors also have support for controlling an external LED. It's
not clear that simply exposing an undecorated output channel is the
correct approach.

Signed-off-by: Crestez Dan Leonard <leonard.cres...@intel.com>
---
 drivers/iio/light/max44000.c | 53 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
index 10a0fe8..1dc10b9 100644
--- a/drivers/iio/light/max44000.c
+++ b/drivers/iio/light/max44000.c
@@ -85,6 +85,13 @@ static const struct iio_chan_spec max44000_channels[] = {
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
        },
+       {
+               .type = IIO_CURRENT,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                                     BIT(IIO_CHAN_INFO_SCALE),
+               .extend_name = "led",
+               .output = 1,
+       },
 };
 
 static inline int max44000_read_alsval(struct max44000_data *data)
@@ -124,6 +131,20 @@ static inline int max44000_write_led_current_raw(struct 
max44000_data *data, int
                                 MAX44000_LED_CURRENT_MASK, val);
 }
 
+static inline int max44000_read_led_current_raw(struct max44000_data *data)
+{
+       unsigned int regval;
+       int ret;
+
+       ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, &regval);
+       if (ret < 0)
+               return ret;
+       regval &= MAX44000_LED_CURRENT_MASK;
+       if (regval >= 8)
+               regval -= 4;
+       return regval;
+}
+
 static int max44000_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int *val, int *val2, long mask)
@@ -153,12 +174,26 @@ static int max44000_read_raw(struct iio_dev *indio_dev,
                        *val = regval;
                        return IIO_VAL_INT;
 
+               case IIO_CURRENT:
+                       mutex_lock(&data->lock);
+                       ret = max44000_read_led_current_raw(data);
+                       mutex_unlock(&data->lock);
+                       if (ret < 0)
+                               return ret;
+                       *val = ret;
+                       return IIO_VAL_INT;
+
                default:
                        return -EINVAL;
                }
 
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
+               case IIO_CURRENT:
+                       /* Output register is in 10s of miliamps */
+                       *val = 10;
+                       return IIO_VAL_INT;
+
                case IIO_LIGHT:
                        *val = 1;
                        *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2;
@@ -173,9 +208,27 @@ static int max44000_read_raw(struct iio_dev *indio_dev,
        }
 }
 
+static int max44000_write_raw(struct iio_dev *indio_dev,
+                             struct iio_chan_spec const *chan,
+                             int val, int val2, long mask)
+{
+       struct max44000_data *data = iio_priv(indio_dev);
+       int ret;
+
+       if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) {
+               mutex_lock(&data->lock);
+               ret = max44000_write_led_current_raw(data, val);
+               mutex_unlock(&data->lock);
+               return ret;
+       }
+
+       return -EINVAL;
+}
+
 static const struct iio_info max44000_info = {
        .driver_module          = THIS_MODULE,
        .read_raw               = max44000_read_raw,
+       .write_raw              = max44000_write_raw,
 };
 
 static bool max44000_readable_reg(struct device *dev, unsigned int reg)
-- 
2.8.0.rc3