On Mon, 7 May 2018 12:08:35 +0800
Richard Tresidder <rtresidd@xxxxxxxxxxxxxxxxx> wrote:
> Adds the ability to run the Mag3110 in continuous mode to speed up the sampling rate.
> Depending on the sampling rate requested the device can be put in or out of continuous mode automatically.
> Shifting out of continuous mode requires a potential 1 / ODR wait which is also implemented
> Modified the sleep method when data is not ready to allow for sampling > 50sps to work.
>
> Signed-off-by: Richard Tresidder <rtresidd@xxxxxxxxxxxxxxxxx>
Hi Richard, much better on the formatting (though the html emails weren't
great before this ;)
Anyhow, one comment I made in v1 review that you missed.
Jonathan
> ---
> diff --git a/drivers/iio/magnetometer/mag3110.c b/drivers/iio/magnetometer/mag3110.c
> index b34ace7..a8ad598 100644
> --- a/drivers/iio/magnetometer/mag3110.c
> +++ b/drivers/iio/magnetometer/mag3110.c
> @@ -26,6 +26,7 @@
> #define MAG3110_OUT_Y 0x03
> #define MAG3110_OUT_Z 0x05
> #define MAG3110_WHO_AM_I 0x07
> +#define MAG3110_SYSMOD 0x08
> #define MAG3110_OFF_X 0x09 /* MSB first */
> #define MAG3110_OFF_Y 0x0b
> #define MAG3110_OFF_Z 0x0d
> @@ -39,6 +40,8 @@
> #define MAG3110_CTRL_DR_SHIFT 5
> #define MAG3110_CTRL_DR_DEFAULT 0
>
> +#define MAG3110_SYSMOD_MODE_MASK (BIT(1) | BIT(0))
I commented on this in V1. Please fix. This would be fine
if it were two one bit fields, it's not so use GENMASK to
remove the false semantic meaning.
> +
> #define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
> #define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
>
> @@ -52,17 +55,20 @@ struct mag3110_data {
> struct i2c_client *client;
> struct mutex lock;
> u8 ctrl_reg1;
> + int sleep_val;
> };
>
> static int mag3110_request(struct mag3110_data *data)
> {
> int ret, tries = 150;
>
> - /* trigger measurement */
> - ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
> - data->ctrl_reg1 | MAG3110_CTRL_TM);
> - if (ret < 0)
> - return ret;
> + if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
> + /* trigger measurement */
> + ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
> + data->ctrl_reg1 | MAG3110_CTRL_TM);
> + if (ret < 0)
> + return ret;
> + }
>
> while (tries-- > 0) {
> ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
> @@ -71,7 +77,11 @@ static int mag3110_request(struct mag3110_data *data)
> /* wait for data ready */
> if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
> break;
> - msleep(20);
> +
> + if (data->sleep_val <= 20)
> + usleep_range(data->sleep_val * 250, data->sleep_val * 500);
> + else
> + msleep(20);
> }
>
> if (tries < 0) {
> @@ -144,6 +154,112 @@ static int mag3110_get_samp_freq_index(struct mag3110_data *data,
> val2);
> }
>
> +static int mag3110_calculate_sleep(struct mag3110_data *data)
> +{
> + int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
> +
> + if(mag3110_samp_freq[i][0] > 0)
> + ret = 1000 / mag3110_samp_freq[i][0];
> + else
> + ret = 1000;
> +
> + return ret == 0 ? 1 : ret;
> +}
> +
> +static int mag3110_standby(struct mag3110_data *data)
> +{
> + return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
> + data->ctrl_reg1 & ~MAG3110_CTRL_AC);
> +}
> +
> +static int mag3110_wait_standby(struct mag3110_data *data)
> +{
> + int ret, tries = 30;
> +
> + /* Takes up to 1/ODR to come out of active mode into stby
> + Longest expected period is 12.5seconds. We'll sleep for 500ms between checks*/
> + while (tries-- > 0) {
> + ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
> + if (ret < 0) {
> + dev_err(&data->client->dev, "i2c error\n");
> + return ret;
> + }
> + /* wait for standby */
> + if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
> + break;
> +
> + msleep_interruptible(500);
> + }
> +
> + if (tries < 0) {
> + dev_err(&data->client->dev, "device not entering standby mode\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int mag3110_active(struct mag3110_data *data)
> +{
> + return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
> + data->ctrl_reg1);
> +}
> +
> +/* returns >0 if active, 0 if in standby and <0 on error */
> +static int mag3110_is_active(struct mag3110_data *data)
> +{
> + int reg;
> +
> + reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
> + if (reg < 0)
> + return reg;
> +
> + return reg & MAG3110_CTRL_AC;
> +}
> +
> +static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
> +{
> + int ret;
> + int is_active;
> +
> + mutex_lock(&data->lock);
> +
> + is_active = mag3110_is_active(data);
> + if (is_active < 0) {
> + ret = is_active;
> + goto fail;
> + }
> +
> + /* config can only be changed when in standby */
> + if (is_active > 0) {
> + ret = mag3110_standby(data);
> + if (ret < 0)
> + goto fail;
> + }
> +
> + /* After coming out of active we must wait for the part to transition to STBY
> + This can take up to 1 /ODR to occur */
> + ret = mag3110_wait_standby(data);
> + if (ret < 0)
> + goto fail;
> +
> + ret = i2c_smbus_write_byte_data(data->client, reg, val);
> + if (ret < 0)
> + goto fail;
> +
> + if (is_active > 0) {
> + ret = mag3110_active(data);
> + if (ret < 0)
> + goto fail;
> + }
> +
> + ret = 0;
> +fail:
> + mutex_unlock(&data->lock);
> +
> + return ret;
> +}
> +
> static int mag3110_read_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> int *val, int *val2, long mask)
> @@ -235,11 +351,13 @@ static int mag3110_write_raw(struct iio_dev *indio_dev,
> ret = -EINVAL;
> break;
> }
> -
> - data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
> + data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK & ~MAG3110_CTRL_AC;
> data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
> - ret = i2c_smbus_write_byte_data(data->client,
> - MAG3110_CTRL_REG1, data->ctrl_reg1);
> + data->sleep_val = mag3110_calculate_sleep(data);
> + if (data->sleep_val < 40)
> + data->ctrl_reg1 |= MAG3110_CTRL_AC;
> +
> + ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
> break;
> case IIO_CHAN_INFO_CALIBBIAS:
> if (val < -10000 || val > 10000) {
> @@ -337,12 +455,6 @@ static irqreturn_t mag3110_trigger_handler(int irq, void *p)
>
> static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
>
> -static int mag3110_standby(struct mag3110_data *data)
> -{
> - return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
> - data->ctrl_reg1 & ~MAG3110_CTRL_AC);
> -}
> -
> static int mag3110_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -374,8 +486,11 @@ static int mag3110_probe(struct i2c_client *client,
> indio_dev->available_scan_masks = mag3110_scan_masks;
>
> data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
> - ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
> - data->ctrl_reg1);
> + data->sleep_val = mag3110_calculate_sleep(data);
> + if (data->sleep_val < 40)
> + data->ctrl_reg1 |= MAG3110_CTRL_AC;
> +
> + ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
> if (ret < 0)
> return ret;
>
>
> --
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