[PATCH v3 2/5] max44000: Initial support for proximity reading

[Crestez Dan Leonard]

The proximity sensor relies on sending pulses to an external IR led and
it is disabled by default on powerup. The driver will enable it with a
default power setting.

Signed-off-by: Crestez Dan Leonard <leonard.cres...@intel.com>
---
 drivers/iio/light/max44000.c | 45 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
index 5ed7934..dc63de2 100644
--- a/drivers/iio/light/max44000.c
+++ b/drivers/iio/light/max44000.c
@@ -59,6 +59,11 @@
  */
 #define MAX44000_REG_CFG_RX_DEFAULT 0xf0
 
+/* REG_TX bits */
+#define MAX44000_LED_CURRENT_MASK      0xf
+#define MAX44000_LED_CURRENT_MAX       11
+#define MAX44000_LED_CURRENT_DEFAULT   6
+
 #define MAX44000_ALSDATA_OVERFLOW      0x4000
 
 struct max44000_data {
@@ -75,6 +80,11 @@ 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_PROXIMITY,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+       },
 };
 
 static int max44000_read_alsval(struct max44000_data *data)
@@ -104,11 +114,23 @@ static int max44000_read_alsval(struct max44000_data 
*data)
        return regval;
 }
 
+static int max44000_write_led_current_raw(struct max44000_data *data, int val)
+{
+       /* Maybe we should clamp the value instead? */
+       if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
+               return -ERANGE;
+       if (val >= 8)
+               val += 4;
+       return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
+                                MAX44000_LED_CURRENT_MASK, val);
+}
+
 static int max44000_read_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);
+       unsigned int regval;
        int ret;
 
        switch (mask) {
@@ -123,6 +145,15 @@ static int max44000_read_raw(struct iio_dev *indio_dev,
                        *val = ret;
                        return IIO_VAL_INT;
 
+               case IIO_PROXIMITY:
+                       mutex_lock(&data->lock);
+                       ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, 
&regval);
+                       mutex_unlock(&data->lock);
+                       if (ret < 0)
+                               return ret;
+                       *val = regval;
+                       return IIO_VAL_INT;
+
                default:
                        return -EINVAL;
                }
@@ -266,8 +297,18 @@ static int max44000_probe(struct i2c_client *client,
                return ret;
        }
 
-       /* Reset CFG bits to ALS-only mode and no interrupts */
-       reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_GIR;
+       /*
+        * By default the LED pulse used for the proximity sensor is disabled.
+        * Set a middle value so that we get some sort of valid data by default.
+        */
+       ret = max44000_write_led_current_raw(data, 
MAX44000_LED_CURRENT_DEFAULT);
+       if (ret < 0) {
+               dev_err(&client->dev, "failed to write init config: %d\n", ret);
+               return ret;
+       }
+
+       /* Reset CFG bits to ALS_PRX mode which allows easy reading of both 
values. */
+       reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX;
        ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
        if (ret < 0) {
                dev_err(&client->dev, "failed to write init config: %d\n", ret);
-- 
2.5.5