#include <linux/gpio.h>
#include "../iio.h"
-#include "magnet.h"
/*
* Register definitions, as well as various shifts and masks to get at the
struct mutex lock;
u8 asa[3];
long raw_to_gauss[3];
- unsigned long mode;
+ bool mode;
u8 reg_cache[AK8975_MAX_REGS];
int eoc_gpio;
int eoc_irq;
};
+static const int ak8975_index_to_reg[] = {
+ AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL,
+};
+
/*
* Helper function to write to the I2C device's registers.
*/
static int ak8975_write_data(struct i2c_client *client,
u8 reg, u8 val, u8 mask, u8 shift)
{
- u8 regval;
- struct i2c_msg msg;
- u8 w_data[2];
- int ret = 0;
-
struct ak8975_data *data = i2c_get_clientdata(client);
+ u8 regval;
+ int ret;
- regval = data->reg_cache[reg];
- regval &= ~mask;
- regval |= val << shift;
-
- w_data[0] = reg;
- w_data[1] = regval;
-
- msg.addr = client->addr;
- msg.flags = 0;
- msg.len = 2;
- msg.buf = w_data;
-
- ret = i2c_transfer(client->adapter, &msg, 1);
+ regval = (data->reg_cache[reg] & ~mask) | (val << shift);
+ ret = i2c_smbus_write_byte_data(client, reg, regval);
if (ret < 0) {
dev_err(&client->dev, "Write to device fails status %x\n", ret);
return ret;
static int ak8975_read_data(struct i2c_client *client,
u8 reg, u8 length, u8 *buffer)
{
- struct i2c_msg msg[2];
- u8 w_data[2];
int ret;
-
- w_data[0] = reg;
-
- msg[0].addr = client->addr;
- msg[0].flags = I2C_M_NOSTART; /* set repeated start and write */
- msg[0].len = 1;
- msg[0].buf = w_data;
-
- msg[1].addr = client->addr;
- msg[1].flags = I2C_M_RD;
- msg[1].len = length;
- msg[1].buf = buffer;
+ struct i2c_msg msg[2] = {
+ {
+ .addr = client->addr,
+ .flags = I2C_M_NOSTART,
+ .len = 1,
+ .buf = ®,
+ }, {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = length,
+ .buf = buffer,
+ }
+ };
ret = i2c_transfer(client->adapter, msg, 2);
if (ret < 0) {
return ret;
}
- /* Precalculate scale factor for each axis and
- store in the device data. */
+/*
+ * Precalculate scale factor (in Gauss units) for each axis and
+ * store in the device data.
+ *
+ * This scale factor is axis-dependent, and is derived from 3 calibration
+ * factors ASA(x), ASA(y), and ASA(z).
+ *
+ * These ASA values are read from the sensor device at start of day, and
+ * cached in the device context struct.
+ *
+ * Adjusting the flux value with the sensitivity adjustment value should be
+ * done via the following formula:
+ *
+ * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
+ *
+ * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
+ * is the resultant adjusted value.
+ *
+ * We reduce the formula to:
+ *
+ * Hadj = H * (ASA + 128) / 256
+ *
+ * H is in the range of -4096 to 4095. The magnetometer has a range of
+ * +-1229uT. To go from the raw value to uT is:
+ *
+ * HuT = H * 1229/4096, or roughly, 3/10.
+ *
+ * Since 1uT = 100 gauss, our final scale factor becomes:
+ *
+ * Hadj = H * ((ASA + 128) / 256) * 3/10 * 100
+ * Hadj = H * ((ASA + 128) * 30 / 256
+ *
+ * Since ASA doesn't change, we cache the resultant scale factor into the
+ * device context in ak8975_setup().
+ */
data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8;
data->raw_to_gauss[1] = ((data->asa[1] + 128) * 30) >> 8;
data->raw_to_gauss[2] = ((data->asa[2] + 128) * 30) >> 8;
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct ak8975_data *data = iio_priv(indio_dev);
- return sprintf(buf, "%lu\n", data->mode);
+ return sprintf(buf, "%u\n", data->mode);
}
/*
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct ak8975_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
- unsigned long oval;
+ bool value;
int ret;
/* Convert mode string and do some basic sanity checking on it.
only 0 or 1 are valid. */
- if (strict_strtoul(buf, 10, &oval))
- return -EINVAL;
-
- if (oval > 1) {
- dev_err(dev, "mode value is not supported\n");
- return -EINVAL;
- }
+ ret = strtobool(buf, &value);
+ if (ret < 0)
+ return ret;
mutex_lock(&data->lock);
/* Write the mode to the device. */
- if (data->mode != oval) {
+ if (data->mode != value) {
ret = ak8975_write_data(client,
AK8975_REG_CNTL,
- (u8)oval,
+ (u8)value,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
mutex_unlock(&data->lock);
return ret;
}
- data->mode = oval;
+ data->mode = value;
}
mutex_unlock(&data->lock);
return count;
}
-/*
- * Emits the scale factor to bring the raw value into Gauss units.
- *
- * This scale factor is axis-dependent, and is derived from 3 calibration
- * factors ASA(x), ASA(y), and ASA(z).
- *
- * These ASA values are read from the sensor device at start of day, and
- * cached in the device context struct.
- *
- * Adjusting the flux value with the sensitivity adjustment value should be
- * done via the following formula:
- *
- * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
- *
- * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
- * is the resultant adjusted value.
- *
- * We reduce the formula to:
- *
- * Hadj = H * (ASA + 128) / 256
- *
- * H is in the range of -4096 to 4095. The magnetometer has a range of
- * +-1229uT. To go from the raw value to uT is:
- *
- * HuT = H * 1229/4096, or roughly, 3/10.
- *
- * Since 1uT = 100 gauss, our final scale factor becomes:
- *
- * Hadj = H * ((ASA + 128) / 256) * 3/10 * 100
- * Hadj = H * ((ASA + 128) * 30 / 256
- *
- * Since ASA doesn't change, we cache the resultant scale factor into the
- * device context in ak8975_setup().
- */
-static ssize_t show_scale(struct device *dev, struct device_attribute *devattr,
- char *buf)
-{
- struct iio_dev *indio_dev = dev_get_drvdata(dev);
- struct ak8975_data *data = iio_priv(indio_dev);
- struct iio_dev_attr *this_attr = to_iio_dev_attr(devattr);
-
- return sprintf(buf, "%ld\n", data->raw_to_gauss[this_attr->address]);
-}
-
static int wait_conversion_complete_gpio(struct ak8975_data *data)
{
struct i2c_client *client = data->client;
/*
* Emits the raw flux value for the x, y, or z axis.
*/
-static ssize_t show_raw(struct device *dev, struct device_attribute *devattr,
- char *buf)
+static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
{
- struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct ak8975_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
- struct iio_dev_attr *this_attr = to_iio_dev_attr(devattr);
u16 meas_reg;
s16 raw;
u8 read_status;
/* Read the flux value from the appropriate register
(the register is specified in the iio device attributes). */
- ret = ak8975_read_data(client, this_attr->address, 2, (u8 *)&meas_reg);
+ ret = ak8975_read_data(client, ak8975_index_to_reg[index],
+ 2, (u8 *)&meas_reg);
if (ret < 0) {
dev_err(&client->dev, "Read axis data fails\n");
goto exit;
/* Clamp to valid range. */
raw = clamp_t(s16, raw, -4096, 4095);
-
- return sprintf(buf, "%d\n", raw);
+ *val = raw;
+ return IIO_VAL_INT;
exit:
mutex_unlock(&data->lock);
return ret;
}
+static int ak8975_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2,
+ long mask)
+{
+ struct ak8975_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case 0:
+ return ak8975_read_axis(indio_dev, chan->address, val);
+ case (1 << IIO_CHAN_INFO_SCALE_SEPARATE):
+ *val = data->raw_to_gauss[chan->address];
+ return IIO_VAL_INT;
+ }
+ return -EINVAL;
+}
+
+#define AK8975_CHANNEL(axis, index) \
+ { \
+ .type = IIO_MAGN, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_##axis, \
+ .info_mask = (1 << IIO_CHAN_INFO_SCALE_SEPARATE), \
+ .address = index, \
+ }
+
+static const struct iio_chan_spec ak8975_channels[] = {
+ AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
+};
+
static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, show_mode, store_mode, 0);
-static IIO_DEV_ATTR_MAGN_X_SCALE(S_IRUGO, show_scale, NULL, 0);
-static IIO_DEV_ATTR_MAGN_Y_SCALE(S_IRUGO, show_scale, NULL, 1);
-static IIO_DEV_ATTR_MAGN_Z_SCALE(S_IRUGO, show_scale, NULL, 2);
-static IIO_DEV_ATTR_MAGN_X(show_raw, AK8975_REG_HXL);
-static IIO_DEV_ATTR_MAGN_Y(show_raw, AK8975_REG_HYL);
-static IIO_DEV_ATTR_MAGN_Z(show_raw, AK8975_REG_HZL);
static struct attribute *ak8975_attr[] = {
&iio_dev_attr_mode.dev_attr.attr,
- &iio_dev_attr_magn_x_scale.dev_attr.attr,
- &iio_dev_attr_magn_y_scale.dev_attr.attr,
- &iio_dev_attr_magn_z_scale.dev_attr.attr,
- &iio_dev_attr_magn_x_raw.dev_attr.attr,
- &iio_dev_attr_magn_y_raw.dev_attr.attr,
- &iio_dev_attr_magn_z_raw.dev_attr.attr,
NULL
};
static const struct iio_info ak8975_info = {
.attrs = &ak8975_attr_group,
+ .read_raw = &ak8975_read_raw,
.driver_module = THIS_MODULE,
};
data->eoc_irq = client->irq;
data->eoc_gpio = eoc_gpio;
indio_dev->dev.parent = &client->dev;
+ indio_dev->channels = ak8975_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
indio_dev->info = &ak8975_info;
indio_dev->modes = INDIO_DIRECT_MODE;
projects / mv-sheeva.git / commitdiff