On Wed, 28 Feb 2024 15:54:57 +0200
Dumitru Ceclan <mitrutzceclan@xxxxxxxxx> wrote:
> Add support for Analog Devices AD7172-2, AD7175-8, AD7177-2.
>
> Signed-off-by: Dumitru Ceclan <mitrutzceclan@xxxxxxxxx>
Hi Dumitru
Some of the changes in here make it clear more inter chip variability
should be specified directly in your device_info structures, and less
(preferably none) use made of the id field + if statements inline.
Those ID fields should just be for matching, not for direct use to adjust
code flow.
Jonathan
> ---
> drivers/iio/adc/ad7173.c | 82 ++++++++++++++++++++++++++++++++++++----
> 1 file changed, 74 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
> index b42fbe28a325..e60ecce20e08 100644
> --- a/drivers/iio/adc/ad7173.c
> +++ b/drivers/iio/adc/ad7173.c
> @@ -1,6 +1,11 @@
> // SPDX-License-Identifier: GPL-2.0+
> /*
> - * AD7172-2/AD7173-8/AD7175-2/AD7176-2 SPI ADC driver
> + * AD717x family SPI ADC driver
> + *
> + * Supported devices:
> + * AD7172-2/AD7172-4/AD7173-8/AD7175-2
> + * AD7175-8/AD7176-2/AD7177-2
> + *
> * Copyright (C) 2015, 2024 Analog Devices, Inc.
> */
>
> @@ -61,10 +66,13 @@
> #define AD7173_AIN_TEMP_POS 17
> #define AD7173_AIN_TEMP_NEG 18
>
> -#define AD7172_ID 0x00d0
> -#define AD7173_ID 0x30d0
> -#define AD7175_ID 0x0cd0
> +#define AD7172_2_ID 0x00d0
> #define AD7176_ID 0x0c90
> +#define AD7175_2_ID 0x0cd0
> +#define AD7172_4_ID 0x2050
> +#define AD7173_ID 0x30d0
> +#define AD7175_8_ID 0x3cd0
> +#define AD7177_ID 0x4fd0
> #define AD7173_ID_MASK GENMASK(15, 4)
>
> #define AD7173_ADC_MODE_REF_EN BIT(15)
> @@ -110,15 +118,19 @@
> #define AD7173_SETUP_REF_SEL_EXT_REF 0x0
> #define AD7173_VOLTAGE_INT_REF_uV 2500000
> #define AD7173_TEMP_SENSIIVITY_uV_per_C 477
> +#define AD7177_ODR_START_VALUE 0x07
>
> #define AD7173_FILTER_ODR0_MASK GENMASK(5, 0)
> #define AD7173_MAX_CONFIGS 8
>
...
>
> static const char *const ad7173_ref_sel_str[] = {
> @@ -656,7 +701,12 @@ static int ad7173_write_raw(struct iio_dev *indio_dev,
> switch (info) {
> case IIO_CHAN_INFO_SAMP_FREQ:
> freq = val * MILLI + val2 / MILLI;
> - for (i = 0; i < st->info->num_sinc5_data_rates - 1; i++)
> + /*
> + * AD7177-2 has the filter values [0-6] marked as reserved
> + * datasheet page 58
> + */
> + i = (st->info->id == AD7177_ID) ? AD7177_ODR_START_VALUE : 0;
Add an st->info->odr_start_value field. Can set it only for this part, but
if in future others turn up that needs similar it becomes very easy to support.
> + for (; i < st->info->num_sinc5_data_rates - 1; i++)
> if (freq >= st->info->sinc5_data_rates[i])
> break;
>
> @@ -908,8 +958,15 @@ static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
> else
> ref_sel = ret;
>
> + if (ref_sel == AD7173_SETUP_REF_SEL_INT_REF &&
> + st->info->id == AD7172_2_ID) {
As below. You may well end up adding more devices here. Make it data instead by
adding has_ref1 boolean to your st->info structure.
> + fwnode_handle_put(child);
> + return dev_err_probe(dev, -EINVAL,
> + "Internal reference is not available on ad7172-2\n");
> + }
> +
> if (ref_sel == AD7173_SETUP_REF_SEL_EXT_REF2 &&
> - st->info->id != AD7173_ID) {
> + st->info->id != AD7173_ID && st->info->id != AD7172_2_ID) {
This is one of those cases that clearly shows why ID matching doesn't generalize well.
Better to have a flag in info that directly says if there is an external reference 2
possible for each chip variant. Otherwise this list just keeps on growing!
!st->info->has_ref2
> fwnode_handle_put(child);
> return dev_err_probe(dev, -EINVAL,
> "External reference 2 is only available on ad7173-8\n");
