| Message ID | 20220903050252.2711950-2-o.rempel@pengutronix.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v5,1/3] dt-bindings: iio: adc: ti,tsc2046: add vref-supply property | expand |
On Sat, Sep 3, 2022 at 8:03 AM Oleksij Rempel <o.rempel@pengutronix.de> wrote: > > If VREF pin is attached, we should use external VREF source instead of > the internal. Otherwise we will get wrong measurements on some of the channel > types. FWIW, Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> > --- > changes v5: > - add "the" before channel > - refactor error handling on regulator registration > - use MILLI instead of 1000 > changes v4: > - use vref_reg pointer instead of bool use_internal_vref > - move regulator registration to a separate function > - rework error handling > - add devm_add_action_or_reset > --- > drivers/iio/adc/ti-tsc2046.c | 57 ++++++++++++++++++++++++++++++++++-- > 1 file changed, 55 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c > index 0d9436a69cbfb..c7601b29b3bef 100644 > --- a/drivers/iio/adc/ti-tsc2046.c > +++ b/drivers/iio/adc/ti-tsc2046.c > @@ -8,7 +8,9 @@ > #include <linux/bitfield.h> > #include <linux/delay.h> > #include <linux/module.h> > +#include <linux/regulator/consumer.h> > #include <linux/spi/spi.h> > +#include <linux/units.h> > > #include <asm/unaligned.h> > > @@ -175,6 +177,8 @@ struct tsc2046_adc_priv { > u32 time_per_bit_ns; > > struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN]; > + unsigned int vref_mv; > + struct regulator *vref_reg; I would put pointer first since it will make sizeof(priv) 4 bytes less on some architectures due to padding elimination. > }; > > #define TI_TSC2046_V_CHAN(index, bits, name) \ > @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx, > case TI_TSC2046_ADDR_AUX: > case TI_TSC2046_ADDR_VBAT: > case TI_TSC2046_ADDR_TEMP0: > - pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON; > + pd |= TI_TSC2046_SER; > + if (!priv->vref_reg) > + pd |= TI_TSC2046_PD1_VREF_ON; > } > > return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd; > @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev, > * So, it is better to use external voltage-divider driver > * instead, which is calculating complete chain. > */ > - *val = TI_TSC2046_INT_VREF; > + *val = priv->vref_mv; > *val2 = chan->scan_type.realbits; > return IIO_VAL_FRACTIONAL_LOG2; > } > @@ -740,6 +746,49 @@ static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv) > } > } > > +static void tsc2046_adc_regulator_disable(void *data) > +{ > + struct tsc2046_adc_priv *priv = data; > + > + regulator_disable(priv->vref_reg); > +} > + > +static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv) > +{ > + struct device *dev = &priv->spi->dev; > + int ret; > + > + priv->vref_reg = devm_regulator_get_optional(dev, "vref"); > + if (IS_ERR(priv->vref_reg)) { > + /* If regulator exists but can't be get, return an error */ > + if (PTR_ERR(priv->vref_reg) != -ENODEV) > + return PTR_ERR(priv->vref_reg); > + priv->vref_reg = NULL; > + } > + if (!priv->vref_reg) { > + /* Use internal reference */ > + priv->vref_mv = TI_TSC2046_INT_VREF; > + return 0; > + } > + > + ret = regulator_enable(priv->vref_reg); > + if (ret) > + return ret; > + > + ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable, > + priv); > + if (ret) > + return ret; > + > + ret = regulator_get_voltage(priv->vref_reg); > + if (ret < 0) > + return ret; > + > + priv->vref_mv = ret / MILLI; > + > + return 0; > +} > + > static int tsc2046_adc_probe(struct spi_device *spi) > { > const struct tsc2046_adc_dcfg *dcfg; > @@ -781,6 +830,10 @@ static int tsc2046_adc_probe(struct spi_device *spi) > indio_dev->num_channels = dcfg->num_channels; > indio_dev->info = &tsc2046_adc_info; > > + ret = tsc2046_adc_configure_regulator(priv); > + if (ret) > + return ret; > + > tsc2046_adc_parse_fwnode(priv); > > ret = tsc2046_adc_setup_spi_msg(priv); > -- > 2.30.2 >
diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c index 0d9436a69cbfb..c7601b29b3bef 100644 --- a/drivers/iio/adc/ti-tsc2046.c +++ b/drivers/iio/adc/ti-tsc2046.c @@ -8,7 +8,9 @@ #include <linux/bitfield.h> #include <linux/delay.h> #include <linux/module.h> +#include <linux/regulator/consumer.h> #include <linux/spi/spi.h> +#include <linux/units.h> #include <asm/unaligned.h> @@ -175,6 +177,8 @@ struct tsc2046_adc_priv { u32 time_per_bit_ns; struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN]; + unsigned int vref_mv; + struct regulator *vref_reg; }; #define TI_TSC2046_V_CHAN(index, bits, name) \ @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx, case TI_TSC2046_ADDR_AUX: case TI_TSC2046_ADDR_VBAT: case TI_TSC2046_ADDR_TEMP0: - pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON; + pd |= TI_TSC2046_SER; + if (!priv->vref_reg) + pd |= TI_TSC2046_PD1_VREF_ON; } return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd; @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev, * So, it is better to use external voltage-divider driver * instead, which is calculating complete chain. */ - *val = TI_TSC2046_INT_VREF; + *val = priv->vref_mv; *val2 = chan->scan_type.realbits; return IIO_VAL_FRACTIONAL_LOG2; } @@ -740,6 +746,49 @@ static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv) } } +static void tsc2046_adc_regulator_disable(void *data) +{ + struct tsc2046_adc_priv *priv = data; + + regulator_disable(priv->vref_reg); +} + +static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv) +{ + struct device *dev = &priv->spi->dev; + int ret; + + priv->vref_reg = devm_regulator_get_optional(dev, "vref"); + if (IS_ERR(priv->vref_reg)) { + /* If regulator exists but can't be get, return an error */ + if (PTR_ERR(priv->vref_reg) != -ENODEV) + return PTR_ERR(priv->vref_reg); + priv->vref_reg = NULL; + } + if (!priv->vref_reg) { + /* Use internal reference */ + priv->vref_mv = TI_TSC2046_INT_VREF; + return 0; + } + + ret = regulator_enable(priv->vref_reg); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable, + priv); + if (ret) + return ret; + + ret = regulator_get_voltage(priv->vref_reg); + if (ret < 0) + return ret; + + priv->vref_mv = ret / MILLI; + + return 0; +} + static int tsc2046_adc_probe(struct spi_device *spi) { const struct tsc2046_adc_dcfg *dcfg; @@ -781,6 +830,10 @@ static int tsc2046_adc_probe(struct spi_device *spi) indio_dev->num_channels = dcfg->num_channels; indio_dev->info = &tsc2046_adc_info; + ret = tsc2046_adc_configure_regulator(priv); + if (ret) + return ret; + tsc2046_adc_parse_fwnode(priv); ret = tsc2046_adc_setup_spi_msg(priv);
If VREF pin is attached, we should use external VREF source instead of the internal. Otherwise we will get wrong measurements on some of the channel types. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- changes v5: - add "the" before channel - refactor error handling on regulator registration - use MILLI instead of 1000 changes v4: - use vref_reg pointer instead of bool use_internal_vref - move regulator registration to a separate function - rework error handling - add devm_add_action_or_reset --- drivers/iio/adc/ti-tsc2046.c | 57 ++++++++++++++++++++++++++++++++++-- 1 file changed, 55 insertions(+), 2 deletions(-)