[PATCH 1/5] iio: light: us5182d: Add property for choosing default power mode

Adriana Reus
2015-11-24T10:59:48Z

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>
---
drivers/iio/light/us5182d.c | 90 +++++++++++++++++++++++++++++++++++++++------
1 file changed, 78 insertions(+), 12 deletions(-)

diff --git a/drivers/iio/light/us5182d.c b/drivers/iio/light/us5182d.c
index 49dab3c..7993014 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;

@@ -182,6 +188,20 @@ static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
* required measurement.
*/
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;
@@ -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[] = {
--
1.9.1