On Wed, 20 Mar 2024 11:04:05 +0100
Andrej Picej <andrej.picej@xxxxxxxxx> wrote:
> Make calibration properties:
> - AVGEN: allow averaging of calibration time,
Confused. How do you average time? Or is this enabling averaging of
ADC readings at calibration time?
> - NRSMPL: select the number of averaging samples during calibration and
Assuming I read AVGEN right, just have a value of 1 in here mean AVGEN is
disabled.
> - TSAMP: specifies the sample time of calibration conversions
Not sure what this means. Is it acquisition time? Is it time after a mux
changes? Anyhow, more info needed.
This is the only one I can see being possibly board related. But if it
is and is needed for calibration, why not for normal read out?
>
> configurable with device tree properties:
> - nxp,calib-avg-en,
> - nxp,calib-nr-samples and
> - nxp,calib-t-samples.
>
> Signed-off-by: Andrej Picej <andrej.picej@xxxxxxxxx>
> ---
> drivers/iio/adc/imx93_adc.c | 66 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 61 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/adc/imx93_adc.c b/drivers/iio/adc/imx93_adc.c
> index 4ccf4819f1f1..ad24105761ab 100644
> --- a/drivers/iio/adc/imx93_adc.c
> +++ b/drivers/iio/adc/imx93_adc.c
> @@ -18,6 +18,7 @@
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> #include <linux/regulator/consumer.h>
> +#include <linux/property.h>
>
> #define IMX93_ADC_DRIVER_NAME "imx93-adc"
>
> @@ -43,6 +44,9 @@
> #define IMX93_ADC_MCR_MODE_MASK BIT(29)
> #define IMX93_ADC_MCR_NSTART_MASK BIT(24)
> #define IMX93_ADC_MCR_CALSTART_MASK BIT(14)
> +#define IMX93_ADC_MCR_AVGEN_MASK BIT(13)
> +#define IMX93_ADC_MCR_NRSMPL_MASK GENMASK(12, 11)
> +#define IMX93_ADC_MCR_TSAMP_MASK GENMASK(10, 9)
> #define IMX93_ADC_MCR_ADCLKSE_MASK BIT(8)
> #define IMX93_ADC_MCR_PWDN_MASK BIT(0)
> #define IMX93_ADC_MSR_CALFAIL_MASK BIT(30)
> @@ -145,7 +149,7 @@ static void imx93_adc_config_ad_clk(struct imx93_adc *adc)
>
> static int imx93_adc_calibration(struct imx93_adc *adc)
> {
> - u32 mcr, msr;
> + u32 mcr, msr, value;
> int ret;
>
> /* make sure ADC in power down mode */
> @@ -156,12 +160,64 @@ static int imx93_adc_calibration(struct imx93_adc *adc)
> mcr &= ~FIELD_PREP(IMX93_ADC_MCR_ADCLKSE_MASK, 1);
> writel(mcr, adc->regs + IMX93_ADC_MCR);
>
> - imx93_adc_power_up(adc);
> -
> /*
> - * TODO: we use the default TSAMP/NRSMPL/AVGEN in MCR,
> - * can add the setting of these bit if need in future.
> + * Set calibration settings:
> + * - AVGEN: allow averaging of calibration time,
> + * - NRSMPL: select the number of averaging samples during calibration,
> + * - TSAMP: specifies the sample time of calibration conversions.
> */
> + if (!device_property_read_u32(adc->dev, "nxp,calib-avg-en", &value)) {
> + mcr &= ~IMX93_ADC_MCR_AVGEN_MASK;
> + mcr |= FIELD_PREP(IMX93_ADC_MCR_AVGEN_MASK, value);
> + }
> +
> + if (!device_property_read_u32(adc->dev, "nxp,calib-nr-samples", &value)) {
Handle error for not present different from a failure to read or similar.
Not present isn't an error, just a fall back to defaults.
For other error codes we should fail the probe.
> + switch (value) {
> + case 16:
> + value = 0x0;
Don't do this in place, meaning of value before this point different to what
you have in it going forwards. Use a different variable name to make that clear.
reg_val vs nr_samples perhaps?
> + break;
> + case 32:
> + value = 0x1;
> + break;
> + case 128:
> + value = 0x2;
> + break;
> + case 512:
> + value = 0x3;
> + break;
> + default:
> + dev_warn(adc->dev, "NRSMPL: wrong value, using default: 512\n");
Fail the probe rather than papering over a wrong value. I'd rather we got the DT fixed
quickly and if someone wanted another value, they really did want it.
We probably do want a default though for the property not being present (given it is new).
so take setting of this variable outside the if(!device_property_read_u32);
> + value = 0x3;
> + }
> + mcr &= ~IMX93_ADC_MCR_NRSMPL_MASK;
> + mcr |= FIELD_PREP(IMX93_ADC_MCR_NRSMPL_MASK, value);
> + }
> +
> + if (!device_property_read_u32(adc->dev, "nxp,calib-t-samples", &value)) {
> + switch (value) {
> + case 8:
> + value = 0x1;
> + break;
> + case 16:
> + value = 0x2;
> + break;
> + case 22:
> + value = 0x0;
> + break;
> + case 32:
> + value = 0x3;
> + break;
> + default:
> + dev_warn(adc->dev, "TSAMP: wrong value, using default: 22\n");
> + value = 0x0;
> + }
> + mcr &= ~IMX93_ADC_MCR_TSAMP_MASK;
> + mcr |= FIELD_PREP(IMX93_ADC_MCR_TSAMP_MASK, value);
> + }
> +
> + writel(mcr, adc->regs + IMX93_ADC_MCR);
> +
> + imx93_adc_power_up(adc);
>
> /* run calibration */
> mcr = readl(adc->regs + IMX93_ADC_MCR);
