iio: light: us5182d: Add property for choosing default power mode

This chip supports two power modes.
1. "one-shot" mode - the chip activates and executes one complete
conversion loop and then shuts itself down. This is the default mode
chosen for raw reads.
2. "continuous" mode - the chip takes continuous measurements.

Continuous mode is more expensive power-wise but may be more reliable.
Add a property so that if preferred, the default power mode for raw
reads can be set to continuous.
Separate one-shot enabling in a separate function that will be used
depending on the chosen power mode. Also create a function for
powering the chip on and off.

Signed-off-by: Adriana Reus <adriana.reus@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 78 insertions, 12 deletions

diff --git a/drivers/iio/light/us5182d.c b/drivers/iio/light/us5182d.c
index 49dab3cb3e23..855f183ba216 100644
--- a/drivers/iio/light/us5182d.c
+++ b/drivers/iio/light/us5182d.c
@@ -99,6 +99,11 @@ enum mode {
         US5182D_PX_ONLY
 };
 
+enum pmode {
+        US5182D_CONTINUOUS,
+        US5182D_ONESHOT
+};
+
 struct us5182d_data {
         struct i2c_client *client;
         struct mutex lock;
@@ -112,6 +117,9 @@ struct us5182d_data {
         u16 *us5182d_dark_ths;
 
         u8 opmode;
+        u8 power_mode;
+
+        bool default_continuous;
 };
 
 static IIO_CONST_ATTR(in_illuminance_scale_available,
@@ -130,13 +138,11 @@ static const struct {
         u8 reg;
         u8 val;
 } us5182d_regvals[] = {
-        {US5182D_REG_CFG0, (US5182D_CFG0_SHUTDOWN_EN |
-                            US5182D_CFG0_WORD_ENABLE)},
+        {US5182D_REG_CFG0, US5182D_CFG0_WORD_ENABLE},
         {US5182D_REG_CFG1, US5182D_CFG1_ALS_RES16},
         {US5182D_REG_CFG2, (US5182D_CFG2_PX_RES16 |
                             US5182D_CFG2_PXGAIN_DEFAULT)},
         {US5182D_REG_CFG3, US5182D_CFG3_LED_CURRENT100},
-        {US5182D_REG_MODE_STORE, US5182D_STORE_MODE},
         {US5182D_REG_CFG4, 0x00},
 };
 
@@ -169,7 +175,7 @@ static int us5182d_get_als(struct us5182d_data *data)
         return result;
 }
 
-static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
+static int us5182d_oneshot_en(struct us5182d_data *data)
 {
         int ret;
 
@@ -183,6 +189,20 @@ static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
          */
         ret = ret | US5182D_CFG0_ONESHOT_EN;
 
+        return i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG0, ret);
+}
+
+static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
+{
+        int ret;
+
+        if (mode == data->opmode)
+                return 0;
+
+        ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CFG0);
+        if (ret < 0)
+                return ret;
+
         /* update mode */
         ret = ret & ~US5182D_OPMODE_MASK;
         ret = ret | (mode << US5182D_OPMODE_SHIFT);
@@ -196,9 +216,6 @@ static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
         if (ret < 0)
                 return ret;
 
-        if (mode == data->opmode)
-                return 0;
-
         ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_MODE_STORE,
                                         US5182D_STORE_MODE);
         if (ret < 0)
@@ -210,6 +227,23 @@ static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
         return 0;
 }
 
+static int us5182d_shutdown_en(struct us5182d_data *data, u8 state)
+{
+        int ret;
+
+        if (data->power_mode == US5182D_ONESHOT)
+                return 0;
+
+        ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CFG0);
+        if (ret < 0)
+                return ret;
+
+        ret = ret & ~US5182D_CFG0_SHUTDOWN_EN;
+        ret = ret | state;
+
+        return i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG0, ret);
+}
+
 static int us5182d_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan, int *val,
                             int *val2, long mask)
@@ -222,6 +256,11 @@ static int us5182d_read_raw(struct iio_dev *indio_dev,
                 switch (chan->type) {
                 case IIO_LIGHT:
                         mutex_lock(&data->lock);
+                        if (data->power_mode == US5182D_ONESHOT) {
+                                ret = us5182d_oneshot_en(data);
+                                if (ret < 0)
+                                        goto out_err;
+                        }
                         ret = us5182d_set_opmode(data, US5182D_OPMODE_ALS);
                         if (ret < 0)
                                 goto out_err;
@@ -234,6 +273,11 @@ static int us5182d_read_raw(struct iio_dev *indio_dev,
                         return IIO_VAL_INT;
                 case IIO_PROXIMITY:
                         mutex_lock(&data->lock);
+                        if (data->power_mode == US5182D_ONESHOT) {
+                                ret = us5182d_oneshot_en(data);
+                                if (ret < 0)
+                                        goto out_err;
+                        }
                         ret = us5182d_set_opmode(data, US5182D_OPMODE_PX);
                         if (ret < 0)
                                 goto out_err;
@@ -368,6 +412,7 @@ static int us5182d_init(struct iio_dev *indio_dev)
                 return ret;
 
         data->opmode = 0;
+        data->power_mode = US5182D_CONTINUOUS;
         for (i = 0; i < ARRAY_SIZE(us5182d_regvals); i++) {
                 ret = i2c_smbus_write_byte_data(data->client,
                                                 us5182d_regvals[i].reg,
@@ -376,7 +421,15 @@ static int us5182d_init(struct iio_dev *indio_dev)
                         return ret;
         }
 
-        return 0;
+        if (!data->default_continuous) {
+                ret = us5182d_shutdown_en(data, US5182D_CFG0_SHUTDOWN_EN);
+                if (ret < 0)
+                        return ret;
+                data->power_mode = US5182D_ONESHOT;
+        }
+
+
+        return ret;
 }
 
 static void us5182d_get_platform_data(struct iio_dev *indio_dev)
@@ -399,6 +452,8 @@ static void us5182d_get_platform_data(struct iio_dev *indio_dev)
                                     "upisemi,lower-dark-gain",
                                     &data->lower_dark_gain))
                 data->lower_dark_gain = US5182D_REG_AUTO_LDARK_GAIN_DEFAULT;
+        data->default_continuous = device_property_read_bool(&data->client->dev,
+                                                             "upisemi,continuous");
 }
 
 static int  us5182d_dark_gain_config(struct iio_dev *indio_dev)
@@ -464,16 +519,27 @@ static int us5182d_probe(struct i2c_client *client,
 
         ret = us5182d_dark_gain_config(indio_dev);
         if (ret < 0)
-                return ret;
+                goto out_err;
+
+        ret = iio_device_register(indio_dev);
+        if (ret < 0)
+                goto out_err;
+
+        return 0;
+
+out_err:
+        us5182d_shutdown_en(data, US5182D_CFG0_SHUTDOWN_EN);
+        return ret;
 
-        return iio_device_register(indio_dev);
 }
 
 static int us5182d_remove(struct i2c_client *client)
 {
+        struct us5182d_data *data = iio_priv(i2c_get_clientdata(client));
+
         iio_device_unregister(i2c_get_clientdata(client));
-        return i2c_smbus_write_byte_data(client, US5182D_REG_CFG0,
-                                         US5182D_CFG0_SHUTDOWN_EN);
+
+        return us5182d_shutdown_en(data, US5182D_CFG0_SHUTDOWN_EN);
 }
 
 static const struct acpi_device_id us5182d_acpi_match[] = {