On 17/03/16 16:43, Gregor Boirie wrote:
> This will be used together with an external trigger (e.g hrtimer based
> software trigger).
>
> Signed-off-by: Gregor Boirie <gregor.boirie@xxxxxxxxxx>
Applied.
I had a slight argument with myself over the data resolution. Its actually
only 13bits, but they pad the rest of the register out to 16 bits. Hence
whilst technically misleading userspace will have an easier time of it if
we claim it was 16bits in the first place (no need to sign extend)
So have left it as is.
Jonathan
> ---
> drivers/iio/magnetometer/Kconfig | 2 +
> drivers/iio/magnetometer/ak8975.c | 135 +++++++++++++++++++++++++++++++-------
> 2 files changed, 112 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> index 021dc53..d9834ed 100644
> --- a/drivers/iio/magnetometer/Kconfig
> +++ b/drivers/iio/magnetometer/Kconfig
> @@ -9,6 +9,8 @@ config AK8975
> tristate "Asahi Kasei AK 3-Axis Magnetometer"
> depends on I2C
> depends on GPIOLIB || COMPILE_TEST
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> help
> Say yes here to build support for Asahi Kasei AK8975, AK8963,
> AK09911 or AK09912 3-Axis Magnetometer.
> diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
> index 3814a6a..de1663d 100644
> --- a/drivers/iio/magnetometer/ak8975.c
> +++ b/drivers/iio/magnetometer/ak8975.c
> @@ -36,6 +36,12 @@
>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/regulator/consumer.h>
> +
> /*
> * Register definitions, as well as various shifts and masks to get at the
> * individual fields of the registers.
> @@ -634,22 +640,15 @@ static int wait_conversion_complete_interrupt(struct ak8975_data *data)
> return ret > 0 ? 0 : -ETIME;
> }
>
> -/*
> - * Emits the raw flux value for the x, y, or z axis.
> - */
> -static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
> +static int ak8975_start_read_axis(struct ak8975_data *data,
> + const struct i2c_client *client)
> {
> - struct ak8975_data *data = iio_priv(indio_dev);
> - struct i2c_client *client = data->client;
> - int ret;
> -
> - mutex_lock(&data->lock);
> -
> /* Set up the device for taking a sample. */
> - ret = ak8975_set_mode(data, MODE_ONCE);
> + int ret = ak8975_set_mode(data, MODE_ONCE);
> +
> if (ret < 0) {
> dev_err(&client->dev, "Error in setting operating mode\n");
> - goto exit;
> + return ret;
> }
>
> /* Wait for the conversion to complete. */
> @@ -660,7 +659,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
> else
> ret = wait_conversion_complete_polled(data);
> if (ret < 0)
> - goto exit;
> + return ret;
>
> /* This will be executed only for non-interrupt based waiting case */
> if (ret & data->def->ctrl_masks[ST1_DRDY]) {
> @@ -668,32 +667,45 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
> data->def->ctrl_regs[ST2]);
> if (ret < 0) {
> dev_err(&client->dev, "Error in reading ST2\n");
> - goto exit;
> + return ret;
> }
> if (ret & (data->def->ctrl_masks[ST2_DERR] |
> data->def->ctrl_masks[ST2_HOFL])) {
> dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
> - ret = -EINVAL;
> - goto exit;
> + return -EINVAL;
> }
> }
>
> - /* Read the flux value from the appropriate register
> - (the register is specified in the iio device attributes). */
> - ret = i2c_smbus_read_word_data(client, data->def->data_regs[index]);
> - if (ret < 0) {
> - dev_err(&client->dev, "Read axis data fails\n");
> + return 0;
> +}
> +
> +/* Retrieve raw flux value for one of the x, y, or z axis. */
> +static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
> +{
> + struct ak8975_data *data = iio_priv(indio_dev);
> + const struct i2c_client *client = data->client;
> + const struct ak_def *def = data->def;
> + int ret;
> +
> + mutex_lock(&data->lock);
> +
> + ret = ak8975_start_read_axis(data, client);
> + if (ret)
> + goto exit;
> +
> + ret = i2c_smbus_read_word_data(client, def->data_regs[index]);
> + if (ret < 0)
> goto exit;
> - }
>
> mutex_unlock(&data->lock);
>
> /* Clamp to valid range. */
> - *val = clamp_t(s16, ret, -data->def->range, data->def->range);
> + *val = clamp_t(s16, ret, -def->range, def->range);
> return IIO_VAL_INT;
>
> exit:
> mutex_unlock(&data->lock);
> + dev_err(&client->dev, "Error in reading axis\n");
> return ret;
> }
>
> @@ -745,12 +757,22 @@ static const struct attribute_group ak8975_attrs_group = {
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> BIT(IIO_CHAN_INFO_SCALE), \
> .address = index, \
> + .scan_index = index, \
> + .scan_type = { \
> + .sign = 's', \
> + .realbits = 16, \
Data sheet says 13bit. Why are we claiming 16? Obviously doesn't have
much practical effect if the top 3 bits are simply the sign bit (seems to
be the case). Anyhow, lets leave this be as it will save userspace doing
the sign extend and it is clearly documented that the top 3 bits will be
correct.
> + .storagebits = 16, \
> + .endianness = IIO_CPU \
> + } \
> }
>
> static const struct iio_chan_spec ak8975_channels[] = {
> AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
> + IIO_CHAN_SOFT_TIMESTAMP(3),
> };
>
> +static const unsigned long ak8975_scan_masks[] = { 0x7, 0 };
> +
> static const struct iio_info ak8975_info = {
> .read_raw = &ak8975_read_raw,
> .driver_module = THIS_MODULE,
> @@ -785,6 +807,56 @@ static const char *ak8975_match_acpi_device(struct device *dev,
> return dev_name(dev);
> }
>
> +static void ak8975_fill_buffer(struct iio_dev *indio_dev)
> +{
> + struct ak8975_data *data = iio_priv(indio_dev);
> + const struct i2c_client *client = data->client;
> + const struct ak_def *def = data->def;
> + int ret;
> + s16 buff[8]; /* 3 x 16 bits axis values + 1 aligned 64 bits timestamp */
> +
> + mutex_lock(&data->lock);
> +
> + ret = ak8975_start_read_axis(data, client);
> + if (ret)
> + goto unlock;
> +
> + /*
> + * For each axis, read the flux value from the appropriate register
> + * (the register is specified in the iio device attributes).
> + */
> + ret = i2c_smbus_read_i2c_block_data_or_emulated(client,
> + def->data_regs[0],
> + 3 * sizeof(buff[0]),
> + (u8 *)buff);
> + if (ret < 0)
> + goto unlock;
> +
> + mutex_unlock(&data->lock);
> +
> + /* Clamp to valid range. */
> + buff[0] = clamp_t(s16, le16_to_cpu(buff[0]), -def->range, def->range);
> + buff[1] = clamp_t(s16, le16_to_cpu(buff[1]), -def->range, def->range);
> + buff[2] = clamp_t(s16, le16_to_cpu(buff[2]), -def->range, def->range);
> +
> + iio_push_to_buffers_with_timestamp(indio_dev, buff, iio_get_time_ns());
> + return;
> +
> +unlock:
> + mutex_unlock(&data->lock);
> + dev_err(&client->dev, "Error in reading axes block\n");
> +}
> +
> +static irqreturn_t ak8975_handle_trigger(int irq, void *p)
> +{
> + const struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> +
> + ak8975_fill_buffer(indio_dev);
> + iio_trigger_notify_done(indio_dev->trig);
> + return IRQ_HANDLED;
> +}
> +
> static int ak8975_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -889,15 +961,27 @@ static int ak8975_probe(struct i2c_client *client,
> indio_dev->dev.parent = &client->dev;
> indio_dev->channels = ak8975_channels;
> indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
> + indio_dev->available_scan_masks = ak8975_scan_masks;
> indio_dev->modes = INDIO_DIRECT_MODE;
> indio_dev->name = name;
>
> - err = iio_device_register(indio_dev);
> - if (err)
> + err = iio_triggered_buffer_setup(indio_dev, NULL, ak8975_handle_trigger,
> + NULL);
> + if (err) {
> + dev_err(&client->dev, "triggered buffer setup failed\n");
> goto power_off;
> + }
> +
> + err = iio_device_register(indio_dev);
> + if (err) {
> + dev_err(&client->dev, "device register failed\n");
> + goto cleanup_buffer;
> + }
>
> return 0;
>
> +cleanup_buffer:
> + iio_triggered_buffer_cleanup(indio_dev);
> power_off:
> ak8975_power_off(client);
> return err;
> @@ -908,6 +992,7 @@ static int ak8975_remove(struct i2c_client *client)
> struct iio_dev *indio_dev = i2c_get_clientdata(client);
>
> iio_device_unregister(indio_dev);
> + iio_triggered_buffer_cleanup(indio_dev);
> ak8975_power_off(client);
>
> return 0;
>
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