* [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb
@ 2017-03-04 16:29 Heiner Kallweit
2017-03-05 12:08 ` Jonathan Cameron
2017-03-18 14:04 ` Martin Blumenstingl
0 siblings, 2 replies; 5+ messages in thread
From: Heiner Kallweit @ 2017-03-04 16:29 UTC (permalink / raw)
To: Jonathan Cameron, Martin Blumenstingl; +Cc: linux-iio
The calibration on Meson GXBB is different from the one on GXM/GXL.
This patch only supports GXBB as I don't have other spec and test hw.
Points 25% vref and 75% vref are used for calibration.
Adding a calibration scale resulted in no improvement, therefore
only a simple calibration bias is supported.
Successfully tested on a Odroid C2. Calibbias is 8 on my system.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- added calibration scale
---
drivers/iio/adc/meson_saradc.c | 74 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 72 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 23710088..d5aa0d04 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -173,7 +173,9 @@
.channel = _chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
- .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_CALIBBIAS) | \
+ BIT(IIO_CHAN_INFO_CALIBSCALE), \
.datasheet_name = "SAR_ADC_CH"#_chan, \
}
@@ -233,6 +235,8 @@ struct meson_sar_adc_priv {
struct clk *adc_div_clk;
struct clk_divider clk_div;
struct completion done;
+ int calibbias;
+ int calibscale;
};
static const struct regmap_config meson_sar_adc_regmap_config = {
@@ -252,6 +256,16 @@ static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
}
+static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
+{
+ struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+ int tmp;
+
+ tmp = div_s64((s64)val * priv->calibscale, 1000000) + priv->calibbias;
+
+ return clamp(tmp, 0, (1 << priv->data->resolution) - 1);
+}
+
static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
@@ -303,7 +317,7 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK,
regval);
fifo_val &= GENMASK(priv->data->resolution - 1, 0);
- *val = fifo_val;
+ *val = meson_sar_adc_calib_val(indio_dev, fifo_val);
return 0;
}
@@ -529,6 +543,15 @@ static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev,
*val2 = priv->data->resolution;
return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_CALIBBIAS:
+ *val = priv->calibbias;
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_CALIBSCALE:
+ *val = priv->calibscale / 1000000;
+ *val2 = priv->calibscale % 1000000;
+ return IIO_VAL_INT_PLUS_MICRO;
+
default:
return -EINVAL;
}
@@ -754,6 +777,47 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data)
return IRQ_HANDLED;
}
+static int meson_sar_adc_calib(struct iio_dev *indio_dev)
+{
+ struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+ int ret, nominal0, nominal1, value0, value1;
+
+ /* use points 25% and 75% for calibration */
+ nominal0 = (1 << priv->data->resolution) / 4;
+ nominal1 = (1 << priv->data->resolution) * 3 / 4;
+
+ meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
+ usleep_range(10, 20);
+ ret = meson_sar_adc_get_sample(indio_dev,
+ &meson_sar_adc_iio_channels[7],
+ MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
+ if (ret < 0)
+ goto out;
+
+ meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
+ usleep_range(10, 20);
+ ret = meson_sar_adc_get_sample(indio_dev,
+ &meson_sar_adc_iio_channels[7],
+ MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
+ if (ret < 0)
+ goto out;
+
+ if (value1 <= value0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ priv->calibscale = div_s64((nominal1 - nominal0) * 1000000LL,
+ value1 - value0);
+ priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale,
+ 1000000);
+ ret = 0;
+out:
+ meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
+
+ return ret;
+}
+
static const struct iio_info meson_sar_adc_iio_info = {
.read_raw = meson_sar_adc_iio_info_read_raw,
.driver_module = THIS_MODULE,
@@ -893,6 +957,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
return PTR_ERR(priv->vref);
}
+ priv->calibscale = 1000000;
+
ret = meson_sar_adc_init(indio_dev);
if (ret)
goto err;
@@ -901,6 +967,10 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
if (ret)
goto err;
+ ret = meson_sar_adc_calib(indio_dev);
+ if (ret)
+ goto err_hw;
+
platform_set_drvdata(pdev, indio_dev);
ret = iio_device_register(indio_dev);
--
2.12.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb
2017-03-04 16:29 [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb Heiner Kallweit
@ 2017-03-05 12:08 ` Jonathan Cameron
2017-03-05 12:22 ` Heiner Kallweit
2017-03-18 14:04 ` Martin Blumenstingl
1 sibling, 1 reply; 5+ messages in thread
From: Jonathan Cameron @ 2017-03-05 12:08 UTC (permalink / raw)
To: Heiner Kallweit, Martin Blumenstingl; +Cc: linux-iio
On 04/03/17 16:29, Heiner Kallweit wrote:
> The calibration on Meson GXBB is different from the one on GXM/GXL.
> This patch only supports GXBB as I don't have other spec and test hw.
> Points 25% vref and 75% vref are used for calibration.
>
> Adding a calibration scale resulted in no improvement, therefore
> only a simple calibration bias is supported.
You probably want to update this description ;)
>
> Successfully tested on a Odroid C2. Calibbias is 8 on my system.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
Looks good to me. Will want Martin's Ack on this, so I'll wait for that
before applying.
Jonathan
> v2:
> - added calibration scale
> ---
> drivers/iio/adc/meson_saradc.c | 74 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 72 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 23710088..d5aa0d04 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -173,7 +173,9 @@
> .channel = _chan, \
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_CALIBBIAS) | \
> + BIT(IIO_CHAN_INFO_CALIBSCALE), \
> .datasheet_name = "SAR_ADC_CH"#_chan, \
> }
>
> @@ -233,6 +235,8 @@ struct meson_sar_adc_priv {
> struct clk *adc_div_clk;
> struct clk_divider clk_div;
> struct completion done;
> + int calibbias;
> + int calibscale;
> };
>
> static const struct regmap_config meson_sar_adc_regmap_config = {
> @@ -252,6 +256,16 @@ static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
> return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
> }
>
> +static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
> +{
> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> + int tmp;
> +
> + tmp = div_s64((s64)val * priv->calibscale, 1000000) + priv->calibbias;
> +
> + return clamp(tmp, 0, (1 << priv->data->resolution) - 1);
> +}
> +
> static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
> {
> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> @@ -303,7 +317,7 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
> fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK,
> regval);
> fifo_val &= GENMASK(priv->data->resolution - 1, 0);
> - *val = fifo_val;
> + *val = meson_sar_adc_calib_val(indio_dev, fifo_val);
>
> return 0;
> }
> @@ -529,6 +543,15 @@ static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev,
> *val2 = priv->data->resolution;
> return IIO_VAL_FRACTIONAL_LOG2;
>
> + case IIO_CHAN_INFO_CALIBBIAS:
> + *val = priv->calibbias;
> + return IIO_VAL_INT;
> +
> + case IIO_CHAN_INFO_CALIBSCALE:
> + *val = priv->calibscale / 1000000;
> + *val2 = priv->calibscale % 1000000;
> + return IIO_VAL_INT_PLUS_MICRO;
> +
> default:
> return -EINVAL;
> }
> @@ -754,6 +777,47 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static int meson_sar_adc_calib(struct iio_dev *indio_dev)
> +{
> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> + int ret, nominal0, nominal1, value0, value1;
> +
> + /* use points 25% and 75% for calibration */
> + nominal0 = (1 << priv->data->resolution) / 4;
> + nominal1 = (1 << priv->data->resolution) * 3 / 4;
> +
> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
> + usleep_range(10, 20);
> + ret = meson_sar_adc_get_sample(indio_dev,
> + &meson_sar_adc_iio_channels[7],
> + MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
> + if (ret < 0)
> + goto out;
> +
> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
> + usleep_range(10, 20);
> + ret = meson_sar_adc_get_sample(indio_dev,
> + &meson_sar_adc_iio_channels[7],
> + MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
> + if (ret < 0)
> + goto out;
> +
> + if (value1 <= value0) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + priv->calibscale = div_s64((nominal1 - nominal0) * 1000000LL,
> + value1 - value0);
> + priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale,
> + 1000000);
> + ret = 0;
> +out:
> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
> +
> + return ret;
> +}
> +
> static const struct iio_info meson_sar_adc_iio_info = {
> .read_raw = meson_sar_adc_iio_info_read_raw,
> .driver_module = THIS_MODULE,
> @@ -893,6 +957,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
> return PTR_ERR(priv->vref);
> }
>
> + priv->calibscale = 1000000;
> +
> ret = meson_sar_adc_init(indio_dev);
> if (ret)
> goto err;
> @@ -901,6 +967,10 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
> if (ret)
> goto err;
>
> + ret = meson_sar_adc_calib(indio_dev);
> + if (ret)
> + goto err_hw;
> +
> platform_set_drvdata(pdev, indio_dev);
>
> ret = iio_device_register(indio_dev);
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb
2017-03-05 12:08 ` Jonathan Cameron
@ 2017-03-05 12:22 ` Heiner Kallweit
0 siblings, 0 replies; 5+ messages in thread
From: Heiner Kallweit @ 2017-03-05 12:22 UTC (permalink / raw)
To: Jonathan Cameron, Martin Blumenstingl; +Cc: linux-iio
Am 05.03.2017 um 13:08 schrieb Jonathan Cameron:
> On 04/03/17 16:29, Heiner Kallweit wrote:
>> The calibration on Meson GXBB is different from the one on GXM/GXL.
>> This patch only supports GXBB as I don't have other spec and test hw.
>> Points 25% vref and 75% vref are used for calibration.
>>
>> Adding a calibration scale resulted in no improvement, therefore
>> only a simple calibration bias is supported.
> You probably want to update this description ;)
Uups, yes .. Will wait for Martin's feedback and send a v3 with
at least a updated commit message.
>>
>> Successfully tested on a Odroid C2. Calibbias is 8 on my system.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>> ---
> Looks good to me. Will want Martin's Ack on this, so I'll wait for that
> before applying.
>
> Jonathan
>> v2:
>> - added calibration scale
>> ---
>> drivers/iio/adc/meson_saradc.c | 74 ++++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 72 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
>> index 23710088..d5aa0d04 100644
>> --- a/drivers/iio/adc/meson_saradc.c
>> +++ b/drivers/iio/adc/meson_saradc.c
>> @@ -173,7 +173,9 @@
>> .channel = _chan, \
>> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>> BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
>> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
>> + BIT(IIO_CHAN_INFO_CALIBBIAS) | \
>> + BIT(IIO_CHAN_INFO_CALIBSCALE), \
>> .datasheet_name = "SAR_ADC_CH"#_chan, \
>> }
>>
>> @@ -233,6 +235,8 @@ struct meson_sar_adc_priv {
>> struct clk *adc_div_clk;
>> struct clk_divider clk_div;
>> struct completion done;
>> + int calibbias;
>> + int calibscale;
>> };
>>
>> static const struct regmap_config meson_sar_adc_regmap_config = {
>> @@ -252,6 +256,16 @@ static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
>> return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
>> }
>>
>> +static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
>> +{
>> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>> + int tmp;
>> +
>> + tmp = div_s64((s64)val * priv->calibscale, 1000000) + priv->calibbias;
>> +
>> + return clamp(tmp, 0, (1 << priv->data->resolution) - 1);
>> +}
>> +
>> static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
>> {
>> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>> @@ -303,7 +317,7 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
>> fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK,
>> regval);
>> fifo_val &= GENMASK(priv->data->resolution - 1, 0);
>> - *val = fifo_val;
>> + *val = meson_sar_adc_calib_val(indio_dev, fifo_val);
>>
>> return 0;
>> }
>> @@ -529,6 +543,15 @@ static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev,
>> *val2 = priv->data->resolution;
>> return IIO_VAL_FRACTIONAL_LOG2;
>>
>> + case IIO_CHAN_INFO_CALIBBIAS:
>> + *val = priv->calibbias;
>> + return IIO_VAL_INT;
>> +
>> + case IIO_CHAN_INFO_CALIBSCALE:
>> + *val = priv->calibscale / 1000000;
>> + *val2 = priv->calibscale % 1000000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> default:
>> return -EINVAL;
>> }
>> @@ -754,6 +777,47 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data)
>> return IRQ_HANDLED;
>> }
>>
>> +static int meson_sar_adc_calib(struct iio_dev *indio_dev)
>> +{
>> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>> + int ret, nominal0, nominal1, value0, value1;
>> +
>> + /* use points 25% and 75% for calibration */
>> + nominal0 = (1 << priv->data->resolution) / 4;
>> + nominal1 = (1 << priv->data->resolution) * 3 / 4;
>> +
>> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
>> + usleep_range(10, 20);
>> + ret = meson_sar_adc_get_sample(indio_dev,
>> + &meson_sar_adc_iio_channels[7],
>> + MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
>> + if (ret < 0)
>> + goto out;
>> +
>> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
>> + usleep_range(10, 20);
>> + ret = meson_sar_adc_get_sample(indio_dev,
>> + &meson_sar_adc_iio_channels[7],
>> + MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
>> + if (ret < 0)
>> + goto out;
>> +
>> + if (value1 <= value0) {
>> + ret = -EINVAL;
>> + goto out;
>> + }
>> +
>> + priv->calibscale = div_s64((nominal1 - nominal0) * 1000000LL,
>> + value1 - value0);
>> + priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale,
>> + 1000000);
>> + ret = 0;
>> +out:
>> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
>> +
>> + return ret;
>> +}
>> +
>> static const struct iio_info meson_sar_adc_iio_info = {
>> .read_raw = meson_sar_adc_iio_info_read_raw,
>> .driver_module = THIS_MODULE,
>> @@ -893,6 +957,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
>> return PTR_ERR(priv->vref);
>> }
>>
>> + priv->calibscale = 1000000;
>> +
>> ret = meson_sar_adc_init(indio_dev);
>> if (ret)
>> goto err;
>> @@ -901,6 +967,10 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
>> if (ret)
>> goto err;
>>
>> + ret = meson_sar_adc_calib(indio_dev);
>> + if (ret)
>> + goto err_hw;
>> +
>> platform_set_drvdata(pdev, indio_dev);
>>
>> ret = iio_device_register(indio_dev);
>>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb
2017-03-04 16:29 [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb Heiner Kallweit
2017-03-05 12:08 ` Jonathan Cameron
@ 2017-03-18 14:04 ` Martin Blumenstingl
2017-03-18 18:30 ` Heiner Kallweit
1 sibling, 1 reply; 5+ messages in thread
From: Martin Blumenstingl @ 2017-03-18 14:04 UTC (permalink / raw)
To: Heiner Kallweit; +Cc: Jonathan Cameron, linux-iio
Hi Heiner,
sorry for the delay, I've been very busy in the last two weeks.
On Sat, Mar 4, 2017 at 5:29 PM, Heiner Kallweit <hkallweit1@gmail.com> wrote:
> The calibration on Meson GXBB is different from the one on GXM/GXL.
> This patch only supports GXBB as I don't have other spec and test hw.
> Points 25% vref and 75% vref are used for calibration.
>
> Adding a calibration scale resulted in no improvement, therefore
> only a simple calibration bias is supported.
>
> Successfully tested on a Odroid C2. Calibbias is 8 on my system.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - added calibration scale
your calibration code seems to work fine, I tested this on a Khadas VIM Pro.
background info:
on the Khadas VIM SAR_ADC_CH1 is wired to VCC through a resistor to
indicate the hardware version, according to the schematics [0] on page
4 the expected ADC value is 512.
512 is due to a bug in Amlogic's Linux saradc driver as it only reads
10bit (while the actual hardware supports 12bit). so actually the
expected ADC value is 2048 (512 << 2).
I confirmed this in the vendor u-boot by running "aradc_12bit open 1;
aradc_12bit read" which gives a value of approx. 2000 (u-boot's saradc
driver doesn't support calibration, so we're pretty close).
before your patch I got a value of somewhere around 2000, with your
patch I get values *very* close to 2048.
thus:
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
some minor comments inline below
> ---
> drivers/iio/adc/meson_saradc.c | 74 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 72 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 23710088..d5aa0d04 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -173,7 +173,9 @@
> .channel = _chan, \
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_CALIBBIAS) | \
> + BIT(IIO_CHAN_INFO_CALIBSCALE), \
> .datasheet_name = "SAR_ADC_CH"#_chan, \
> }
>
> @@ -233,6 +235,8 @@ struct meson_sar_adc_priv {
> struct clk *adc_div_clk;
> struct clk_divider clk_div;
> struct completion done;
> + int calibbias;
> + int calibscale;
> };
>
> static const struct regmap_config meson_sar_adc_regmap_config = {
> @@ -252,6 +256,16 @@ static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
> return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
> }
>
> +static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
> +{
> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> + int tmp;
> +
> + tmp = div_s64((s64)val * priv->calibscale, 1000000) + priv->calibbias;
> +
> + return clamp(tmp, 0, (1 << priv->data->resolution) - 1);
> +}
> +
this logic is slightly different than in Amlogic's driver (which
basically uses "val - actual_value_of(CHAN7_MUX_VDD_DIV2)" instead of
"val"), see [1]. this does NOT mean that you have to change your code,
although it would be nice if you could add a comment how this magic^W
math works!
> static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
> {
> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> @@ -303,7 +317,7 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
> fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK,
> regval);
> fifo_val &= GENMASK(priv->data->resolution - 1, 0);
> - *val = fifo_val;
> + *val = meson_sar_adc_calib_val(indio_dev, fifo_val);
>
> return 0;
> }
> @@ -529,6 +543,15 @@ static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev,
> *val2 = priv->data->resolution;
> return IIO_VAL_FRACTIONAL_LOG2;
>
> + case IIO_CHAN_INFO_CALIBBIAS:
> + *val = priv->calibbias;
> + return IIO_VAL_INT;
> +
> + case IIO_CHAN_INFO_CALIBSCALE:
> + *val = priv->calibscale / 1000000;
> + *val2 = priv->calibscale % 1000000;
can we add a #define for 1000000? it's used very often in the driver
which makes it a bit hard to read.
> + return IIO_VAL_INT_PLUS_MICRO;
> +
> default:
> return -EINVAL;
> }
> @@ -754,6 +777,47 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static int meson_sar_adc_calib(struct iio_dev *indio_dev)
> +{
> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> + int ret, nominal0, nominal1, value0, value1;
> +
> + /* use points 25% and 75% for calibration */
> + nominal0 = (1 << priv->data->resolution) / 4;
> + nominal1 = (1 << priv->data->resolution) * 3 / 4;
> +
> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
> + usleep_range(10, 20);
> + ret = meson_sar_adc_get_sample(indio_dev,
> + &meson_sar_adc_iio_channels[7],
> + MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
> + if (ret < 0)
> + goto out;
> +
> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
> + usleep_range(10, 20);
> + ret = meson_sar_adc_get_sample(indio_dev,
> + &meson_sar_adc_iio_channels[7],
> + MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
> + if (ret < 0)
> + goto out;
> +
> + if (value1 <= value0) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + priv->calibscale = div_s64((nominal1 - nominal0) * 1000000LL,
> + value1 - value0);
> + priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale,
> + 1000000);
> + ret = 0;
> +out:
> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
> +
> + return ret;
> +}
> +
> static const struct iio_info meson_sar_adc_iio_info = {
> .read_raw = meson_sar_adc_iio_info_read_raw,
> .driver_module = THIS_MODULE,
> @@ -893,6 +957,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
> return PTR_ERR(priv->vref);
> }
>
> + priv->calibscale = 1000000;
> +
> ret = meson_sar_adc_init(indio_dev);
> if (ret)
> goto err;
> @@ -901,6 +967,10 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
> if (ret)
> goto err;
>
> + ret = meson_sar_adc_calib(indio_dev);
> + if (ret)
> + goto err_hw;
> +
should we fail here if calibration did not work? we could use the
non-calibrated value as fallback (I think all that would have to be
done is changing this to not error out, as you're initializing
calibscale above already, and calibbias will be 0 by default)
> platform_set_drvdata(pdev, indio_dev);
>
> ret = iio_device_register(indio_dev);
> --
> 2.12.0
>
>
if anyone is interested in before and after statistics:
values before your patch:
/sys/bus/iio/devices/iio:device0/in_voltage0_mean_raw:3993
/sys/bus/iio/devices/iio:device0/in_voltage0_raw:4009
/sys/bus/iio/devices/iio:device0/in_voltage1_mean_raw:2001
/sys/bus/iio/devices/iio:device0/in_voltage1_raw:1992
/sys/bus/iio/devices/iio:device0/in_voltage2_mean_raw:487
/sys/bus/iio/devices/iio:device0/in_voltage2_raw:408
/sys/bus/iio/devices/iio:device0/in_voltage3_mean_raw:386
/sys/bus/iio/devices/iio:device0/in_voltage3_raw:356
/sys/bus/iio/devices/iio:device0/in_voltage4_mean_raw:466
/sys/bus/iio/devices/iio:device0/in_voltage4_raw:476
/sys/bus/iio/devices/iio:device0/in_voltage5_mean_raw:470
/sys/bus/iio/devices/iio:device0/in_voltage5_raw:469
/sys/bus/iio/devices/iio:device0/in_voltage6_mean_raw:2199
/sys/bus/iio/devices/iio:device0/in_voltage6_raw:2197
/sys/bus/iio/devices/iio:device0/in_voltage7_mean_raw:829
/sys/bus/iio/devices/iio:device0/in_voltage7_raw:492
/sys/bus/iio/devices/iio:device0/in_voltage_scale:0.439453125
/sys/bus/iio/devices/iio:device0/name:meson-gxl-saradc
values after your patch:
/sys/bus/iio/devices/iio:device0/in_voltage0_mean_raw:4095
/sys/bus/iio/devices/iio:device0/in_voltage0_raw:4095
/sys/bus/iio/devices/iio:device0/in_voltage1_mean_raw:2044
/sys/bus/iio/devices/iio:device0/in_voltage1_raw:2044
/sys/bus/iio/devices/iio:device0/in_voltage2_mean_raw:487
/sys/bus/iio/devices/iio:device0/in_voltage2_raw:404
/sys/bus/iio/devices/iio:device0/in_voltage3_mean_raw:383
/sys/bus/iio/devices/iio:device0/in_voltage3_raw:373
/sys/bus/iio/devices/iio:device0/in_voltage4_mean_raw:466
/sys/bus/iio/devices/iio:device0/in_voltage4_raw:478
/sys/bus/iio/devices/iio:device0/in_voltage5_mean_raw:470
/sys/bus/iio/devices/iio:device0/in_voltage5_raw:472
/sys/bus/iio/devices/iio:device0/in_voltage6_mean_raw:2269
/sys/bus/iio/devices/iio:device0/in_voltage6_raw:2257
/sys/bus/iio/devices/iio:device0/in_voltage7_mean_raw:837
/sys/bus/iio/devices/iio:device0/in_voltage7_raw:488
/sys/bus/iio/devices/iio:device0/in_voltage_calibbias:-12
/sys/bus/iio/devices/iio:device0/in_voltage_calibscale:1.026566
/sys/bus/iio/devices/iio:device0/in_voltage_scale:0.439453125
/sys/bus/iio/devices/iio:device0/name:meson-gxl-saradc
many thanks again for this contribution Heiner!
Regards,
Martin
[0] https://github.com/khadas/documents/blob/master/Vim_V12_Sch.pdf
[1] https://github.com/khadas/linux/blob/9ff62f1c4e333feb64bc419191215cec2c7c7c73/drivers/amlogic/input/saradc/saradc.c#L174
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb
2017-03-18 14:04 ` Martin Blumenstingl
@ 2017-03-18 18:30 ` Heiner Kallweit
0 siblings, 0 replies; 5+ messages in thread
From: Heiner Kallweit @ 2017-03-18 18:30 UTC (permalink / raw)
To: Martin Blumenstingl; +Cc: Jonathan Cameron, linux-iio
Am 18.03.2017 um 15:04 schrieb Martin Blumenstingl:
> Hi Heiner,
>
> sorry for the delay, I've been very busy in the last two weeks.
>
> On Sat, Mar 4, 2017 at 5:29 PM, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>> The calibration on Meson GXBB is different from the one on GXM/GXL.
>> This patch only supports GXBB as I don't have other spec and test hw.
>> Points 25% vref and 75% vref are used for calibration.
>>
>> Adding a calibration scale resulted in no improvement, therefore
>> only a simple calibration bias is supported.
>>
>> Successfully tested on a Odroid C2. Calibbias is 8 on my system.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>> ---
>> v2:
>> - added calibration scale
> your calibration code seems to work fine, I tested this on a Khadas VIM Pro.
>
> background info:
> on the Khadas VIM SAR_ADC_CH1 is wired to VCC through a resistor to
> indicate the hardware version, according to the schematics [0] on page
> 4 the expected ADC value is 512.
> 512 is due to a bug in Amlogic's Linux saradc driver as it only reads
> 10bit (while the actual hardware supports 12bit). so actually the
> expected ADC value is 2048 (512 << 2).
> I confirmed this in the vendor u-boot by running "aradc_12bit open 1;
> aradc_12bit read" which gives a value of approx. 2000 (u-boot's saradc
> driver doesn't support calibration, so we're pretty close).
>
> before your patch I got a value of somewhere around 2000, with your
> patch I get values *very* close to 2048.
> thus:
> Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
>
> some minor comments inline below
>
>> ---
>> drivers/iio/adc/meson_saradc.c | 74 ++++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 72 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
>> index 23710088..d5aa0d04 100644
>> --- a/drivers/iio/adc/meson_saradc.c
>> +++ b/drivers/iio/adc/meson_saradc.c
>> @@ -173,7 +173,9 @@
>> .channel = _chan, \
>> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>> BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
>> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
>> + BIT(IIO_CHAN_INFO_CALIBBIAS) | \
>> + BIT(IIO_CHAN_INFO_CALIBSCALE), \
>> .datasheet_name = "SAR_ADC_CH"#_chan, \
>> }
>>
>> @@ -233,6 +235,8 @@ struct meson_sar_adc_priv {
>> struct clk *adc_div_clk;
>> struct clk_divider clk_div;
>> struct completion done;
>> + int calibbias;
>> + int calibscale;
>> };
>>
>> static const struct regmap_config meson_sar_adc_regmap_config = {
>> @@ -252,6 +256,16 @@ static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
>> return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
>> }
>>
>> +static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
>> +{
>> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>> + int tmp;
>> +
>> + tmp = div_s64((s64)val * priv->calibscale, 1000000) + priv->calibbias;
>> +
>> + return clamp(tmp, 0, (1 << priv->data->resolution) - 1);
>> +}
>> +
> this logic is slightly different than in Amlogic's driver (which
> basically uses "val - actual_value_of(CHAN7_MUX_VDD_DIV2)" instead of
> "val"), see [1]. this does NOT mean that you have to change your code,
> although it would be nice if you could add a comment how this magic^W
> math works!
>
The logic here is basically determined by the parameters CALIBSCALE and
CALIBBIAS in the core code.
The calibration function is: SCALE * val + BIAS
I'll add a comment to the calculation.
>> static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
>> {
>> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>> @@ -303,7 +317,7 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
>> fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK,
>> regval);
>> fifo_val &= GENMASK(priv->data->resolution - 1, 0);
>> - *val = fifo_val;
>> + *val = meson_sar_adc_calib_val(indio_dev, fifo_val);
>>
>> return 0;
>> }
>> @@ -529,6 +543,15 @@ static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev,
>> *val2 = priv->data->resolution;
>> return IIO_VAL_FRACTIONAL_LOG2;
>>
>> + case IIO_CHAN_INFO_CALIBBIAS:
>> + *val = priv->calibbias;
>> + return IIO_VAL_INT;
>> +
>> + case IIO_CHAN_INFO_CALIBSCALE:
>> + *val = priv->calibscale / 1000000;
>> + *val2 = priv->calibscale % 1000000;
> can we add a #define for 1000000? it's used very often in the driver
> which makes it a bit hard to read.
>
I'll call the define MILLION to make clear it's not a factor that
can be simply changed. This would brake calculation of val2 for
IIO_CHAN_INFO_CALIBSCALE.
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> default:
>> return -EINVAL;
>> }
>> @@ -754,6 +777,47 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data)
>> return IRQ_HANDLED;
>> }
>>
>> +static int meson_sar_adc_calib(struct iio_dev *indio_dev)
>> +{
>> + struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
>> + int ret, nominal0, nominal1, value0, value1;
>> +
>> + /* use points 25% and 75% for calibration */
>> + nominal0 = (1 << priv->data->resolution) / 4;
>> + nominal1 = (1 << priv->data->resolution) * 3 / 4;
>> +
>> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
>> + usleep_range(10, 20);
>> + ret = meson_sar_adc_get_sample(indio_dev,
>> + &meson_sar_adc_iio_channels[7],
>> + MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
>> + if (ret < 0)
>> + goto out;
>> +
>> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
>> + usleep_range(10, 20);
>> + ret = meson_sar_adc_get_sample(indio_dev,
>> + &meson_sar_adc_iio_channels[7],
>> + MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
>> + if (ret < 0)
>> + goto out;
>> +
>> + if (value1 <= value0) {
>> + ret = -EINVAL;
>> + goto out;
>> + }
>> +
>> + priv->calibscale = div_s64((nominal1 - nominal0) * 1000000LL,
>> + value1 - value0);
>> + priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale,
>> + 1000000);
>> + ret = 0;
>> +out:
>> + meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
>> +
>> + return ret;
>> +}
>> +
>> static const struct iio_info meson_sar_adc_iio_info = {
>> .read_raw = meson_sar_adc_iio_info_read_raw,
>> .driver_module = THIS_MODULE,
>> @@ -893,6 +957,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
>> return PTR_ERR(priv->vref);
>> }
>>
>> + priv->calibscale = 1000000;
>> +
>> ret = meson_sar_adc_init(indio_dev);
>> if (ret)
>> goto err;
>> @@ -901,6 +967,10 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
>> if (ret)
>> goto err;
>>
>> + ret = meson_sar_adc_calib(indio_dev);
>> + if (ret)
>> + goto err_hw;
>> +
> should we fail here if calibration did not work? we could use the
> non-calibrated value as fallback (I think all that would have to be
> done is changing this to not error out, as you're initializing
> calibscale above already, and calibbias will be 0 by default)
>
Technically, if the calibration fails something is terribly wrong
and most likely all other further samplings will fail too.
But in general you're right, we have a fallback and there's no
urgent need to bail out. So I will change this to just print
a warning that the calibration failed.
>> platform_set_drvdata(pdev, indio_dev);
>>
>> ret = iio_device_register(indio_dev);
>> --
>> 2.12.0
>>
>>
>
> if anyone is interested in before and after statistics:
>
> values before your patch:
> /sys/bus/iio/devices/iio:device0/in_voltage0_mean_raw:3993
> /sys/bus/iio/devices/iio:device0/in_voltage0_raw:4009
> /sys/bus/iio/devices/iio:device0/in_voltage1_mean_raw:2001
> /sys/bus/iio/devices/iio:device0/in_voltage1_raw:1992
> /sys/bus/iio/devices/iio:device0/in_voltage2_mean_raw:487
> /sys/bus/iio/devices/iio:device0/in_voltage2_raw:408
> /sys/bus/iio/devices/iio:device0/in_voltage3_mean_raw:386
> /sys/bus/iio/devices/iio:device0/in_voltage3_raw:356
> /sys/bus/iio/devices/iio:device0/in_voltage4_mean_raw:466
> /sys/bus/iio/devices/iio:device0/in_voltage4_raw:476
> /sys/bus/iio/devices/iio:device0/in_voltage5_mean_raw:470
> /sys/bus/iio/devices/iio:device0/in_voltage5_raw:469
> /sys/bus/iio/devices/iio:device0/in_voltage6_mean_raw:2199
> /sys/bus/iio/devices/iio:device0/in_voltage6_raw:2197
> /sys/bus/iio/devices/iio:device0/in_voltage7_mean_raw:829
> /sys/bus/iio/devices/iio:device0/in_voltage7_raw:492
> /sys/bus/iio/devices/iio:device0/in_voltage_scale:0.439453125
> /sys/bus/iio/devices/iio:device0/name:meson-gxl-saradc
>
> values after your patch:
> /sys/bus/iio/devices/iio:device0/in_voltage0_mean_raw:4095
> /sys/bus/iio/devices/iio:device0/in_voltage0_raw:4095
> /sys/bus/iio/devices/iio:device0/in_voltage1_mean_raw:2044
> /sys/bus/iio/devices/iio:device0/in_voltage1_raw:2044
> /sys/bus/iio/devices/iio:device0/in_voltage2_mean_raw:487
> /sys/bus/iio/devices/iio:device0/in_voltage2_raw:404
> /sys/bus/iio/devices/iio:device0/in_voltage3_mean_raw:383
> /sys/bus/iio/devices/iio:device0/in_voltage3_raw:373
> /sys/bus/iio/devices/iio:device0/in_voltage4_mean_raw:466
> /sys/bus/iio/devices/iio:device0/in_voltage4_raw:478
> /sys/bus/iio/devices/iio:device0/in_voltage5_mean_raw:470
> /sys/bus/iio/devices/iio:device0/in_voltage5_raw:472
> /sys/bus/iio/devices/iio:device0/in_voltage6_mean_raw:2269
> /sys/bus/iio/devices/iio:device0/in_voltage6_raw:2257
> /sys/bus/iio/devices/iio:device0/in_voltage7_mean_raw:837
> /sys/bus/iio/devices/iio:device0/in_voltage7_raw:488
> /sys/bus/iio/devices/iio:device0/in_voltage_calibbias:-12
> /sys/bus/iio/devices/iio:device0/in_voltage_calibscale:1.026566
> /sys/bus/iio/devices/iio:device0/in_voltage_scale:0.439453125
> /sys/bus/iio/devices/iio:device0/name:meson-gxl-saradc
>
> many thanks again for this contribution Heiner!
>
>
> Regards,
> Martin
>
>
> [0] https://github.com/khadas/documents/blob/master/Vim_V12_Sch.pdf
> [1] https://github.com/khadas/linux/blob/9ff62f1c4e333feb64bc419191215cec2c7c7c73/drivers/amlogic/input/saradc/saradc.c#L174
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-03-18 18:30 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-04 16:29 [PATCH v2] iio: adc: meson-saradc: add calibration for meson gxbb Heiner Kallweit
2017-03-05 12:08 ` Jonathan Cameron
2017-03-05 12:22 ` Heiner Kallweit
2017-03-18 14:04 ` Martin Blumenstingl
2017-03-18 18:30 ` Heiner Kallweit
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