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Date: Sat, 13 Aug 2022 01:03:54 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Eddie James <eajames@...ux.ibm.com>
Cc: linux-iio <linux-iio@...r.kernel.org>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Joel Stanley <joel@....id.au>
Subject: Re: [PATCH v4 1/2] iio: pressure: dps310: Refactor startup procedure
On Wed, Aug 10, 2022 at 12:12 AM Eddie James <eajames@...ux.ibm.com> wrote:
>
> Move the startup procedure into a function, and correct a missing
> check on the return code for writing the PRS_CFG register.
Code looks good, one remark below.
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: Eddie James <eajames@...ux.ibm.com>
> Reviewed-by: Joel Stanley <joel@....id.au>
> ---
> drivers/iio/pressure/dps310.c | 188 ++++++++++++++++++----------------
> 1 file changed, 99 insertions(+), 89 deletions(-)
>
> diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
> index 36fb7ae0d0a9..c706a8b423b5 100644
> --- a/drivers/iio/pressure/dps310.c
> +++ b/drivers/iio/pressure/dps310.c
> @@ -159,6 +159,102 @@ static int dps310_get_coefs(struct dps310_data *data)
> return 0;
> }
>
> +/*
> + * Some versions of the chip will read temperatures in the ~60C range when
> + * it's actually ~20C. This is the manufacturer recommended workaround
> + * to correct the issue. The registers used below are undocumented.
> + */
> +static int dps310_temp_workaround(struct dps310_data *data)
> +{
> + int rc;
> + int reg;
> +
> + rc = regmap_read(data->regmap, 0x32, ®);
> + if (rc)
> + return rc;
> +
> + /*
> + * If bit 1 is set then the device is okay, and the workaround does not
> + * need to be applied
> + */
> + if (reg & BIT(1))
> + return 0;
> +
> + rc = regmap_write(data->regmap, 0x0e, 0xA5);
> + if (rc)
> + return rc;
> +
> + rc = regmap_write(data->regmap, 0x0f, 0x96);
> + if (rc)
> + return rc;
This code already exists, but still want to ask, is it really
byte-registers here and not be16/le16 one? In such a case perhaps bulk
write can be used to reflect it better?
> + rc = regmap_write(data->regmap, 0x62, 0x02);
> + if (rc)
> + return rc;
> +
> + rc = regmap_write(data->regmap, 0x0e, 0x00);
> + if (rc)
> + return rc;
> +
> + return regmap_write(data->regmap, 0x0f, 0x00);
Ditto.
> +}
> +
> +static int dps310_startup(struct dps310_data *data)
> +{
> + int rc;
> + int ready;
> +
> + /*
> + * Set up pressure sensor in single sample, one measurement per second
> + * mode
> + */
> + rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0);
> + if (rc)
> + return rc;
> +
> + /*
> + * Set up external (MEMS) temperature sensor in single sample, one
> + * measurement per second mode
> + */
> + rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT);
> + if (rc)
> + return rc;
> +
> + /* Temp and pressure shifts are disabled when PRC <= 8 */
> + rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
> + DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0);
> + if (rc)
> + return rc;
> +
> + /* MEAS_CFG doesn't update correctly unless first written with 0 */
> + rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
> + DPS310_MEAS_CTRL_BITS, 0);
> + if (rc)
> + return rc;
> +
> + /* Turn on temperature and pressure measurement in the background */
> + rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
> + DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN |
> + DPS310_TEMP_EN | DPS310_BACKGROUND);
> + if (rc)
> + return rc;
> +
> + /*
> + * Calibration coefficients required for reporting temperature.
> + * They are available 40ms after the device has started
> + */
> + rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
> + ready & DPS310_COEF_RDY, 10000, 40000);
> + if (rc)
> + return rc;
> +
> + rc = dps310_get_coefs(data);
> + if (rc)
> + return rc;
> +
> + return dps310_temp_workaround(data);
> +}
> +
> static int dps310_get_pres_precision(struct dps310_data *data)
> {
> int rc;
> @@ -677,52 +773,12 @@ static const struct iio_info dps310_info = {
> .write_raw = dps310_write_raw,
> };
>
> -/*
> - * Some verions of chip will read temperatures in the ~60C range when
> - * its actually ~20C. This is the manufacturer recommended workaround
> - * to correct the issue. The registers used below are undocumented.
> - */
> -static int dps310_temp_workaround(struct dps310_data *data)
> -{
> - int rc;
> - int reg;
> -
> - rc = regmap_read(data->regmap, 0x32, ®);
> - if (rc < 0)
> - return rc;
> -
> - /*
> - * If bit 1 is set then the device is okay, and the workaround does not
> - * need to be applied
> - */
> - if (reg & BIT(1))
> - return 0;
> -
> - rc = regmap_write(data->regmap, 0x0e, 0xA5);
> - if (rc < 0)
> - return rc;
> -
> - rc = regmap_write(data->regmap, 0x0f, 0x96);
> - if (rc < 0)
> - return rc;
> -
> - rc = regmap_write(data->regmap, 0x62, 0x02);
> - if (rc < 0)
> - return rc;
> -
> - rc = regmap_write(data->regmap, 0x0e, 0x00);
> - if (rc < 0)
> - return rc;
> -
> - return regmap_write(data->regmap, 0x0f, 0x00);
> -}
> -
> static int dps310_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> struct dps310_data *data;
> struct iio_dev *iio;
> - int rc, ready;
> + int rc;
>
> iio = devm_iio_device_alloc(&client->dev, sizeof(*data));
> if (!iio)
> @@ -747,54 +803,8 @@ static int dps310_probe(struct i2c_client *client,
> if (rc)
> return rc;
>
> - /*
> - * Set up pressure sensor in single sample, one measurement per second
> - * mode
> - */
> - rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0);
> -
> - /*
> - * Set up external (MEMS) temperature sensor in single sample, one
> - * measurement per second mode
> - */
> - rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT);
> - if (rc < 0)
> - return rc;
> -
> - /* Temp and pressure shifts are disabled when PRC <= 8 */
> - rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
> - DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0);
> - if (rc < 0)
> - return rc;
> -
> - /* MEAS_CFG doesn't update correctly unless first written with 0 */
> - rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
> - DPS310_MEAS_CTRL_BITS, 0);
> - if (rc < 0)
> - return rc;
> -
> - /* Turn on temperature and pressure measurement in the background */
> - rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
> - DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN |
> - DPS310_TEMP_EN | DPS310_BACKGROUND);
> - if (rc < 0)
> - return rc;
> -
> - /*
> - * Calibration coefficients required for reporting temperature.
> - * They are available 40ms after the device has started
> - */
> - rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
> - ready & DPS310_COEF_RDY, 10000, 40000);
> - if (rc < 0)
> - return rc;
> -
> - rc = dps310_get_coefs(data);
> - if (rc < 0)
> - return rc;
> -
> - rc = dps310_temp_workaround(data);
> - if (rc < 0)
> + rc = dps310_startup(data);
> + if (rc)
> return rc;
>
> rc = devm_iio_device_register(&client->dev, iio);
> --
> 2.31.1
>
--
With Best Regards,
Andy Shevchenko
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