[PATCH 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 | 61 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
index 7c12153..10a0fe8 100644
--- a/drivers/iio/light/max44000.c
+++ b/drivers/iio/light/max44000.c
@@ -41,6 +41,23 @@
 #define MAX44000_REG_TRIM_GAIN_GREEN   0x0f
 #define MAX44000_REG_TRIM_GAIN_IR      0x10
 
+/* REG_CFG bits */
+#define MAX44000_CFG_ALSINTE           0x01
+#define MAX44000_CFG_PRXINTE           0x02
+#define MAX44000_CFG_MASK              0x1c
+#define MAX44000_CFG_MODE_SHUTDOWN     0x00
+#define MAX44000_CFG_MODE_ALS_GIR      0x04
+#define MAX44000_CFG_MODE_ALS_G                0x08
+#define MAX44000_CFG_MODE_ALS_IR       0x0c
+#define MAX44000_CFG_MODE_ALS_PRX      0x10
+#define MAX44000_CFG_MODE_PRX          0x14
+#define MAX44000_CFG_TRIM              0x20
+
+/* 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
 
 #define MAX44000_REGMASK_READABLE      0x419fff
@@ -60,6 +77,12 @@ static const struct iio_chan_spec max44000_channels[] = {
        {
                .type = IIO_LIGHT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
+                                           BIT(IIO_CHAN_INFO_INT_TIME),
+       },
+       {
+               .type = IIO_PROXIMITY,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
        },
 };
@@ -90,11 +113,23 @@ static inline int max44000_read_alsval(struct 
max44000_data *data)
        return regval;
 }
 
+static inline 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) {
@@ -109,6 +144,15 @@ 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;
                }
@@ -244,6 +288,23 @@ static int max44000_probe(struct i2c_client *client,
                return ret;
        }
 
+       /* 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(&data->client->dev, "failed to write init config: 
%d\n", ret);
+               return ret;
+       }
+
+       /* By default set in 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(&data->client->dev, "failed to write init config: 
%d\n", ret);
+               return ret;
+       }
+
        return iio_device_register(indio_dev);
 }
 
-- 
2.8.0.rc3