Re: [PATCH v2 7/9] iio: dac: ad3552r: extract common code (no changes in behavior intended)

From: Jonathan Cameron
Date: Sun Sep 08 2024 - 11:42:55 EST

On Thu, 05 Sep 2024 17:17:37 +0200
Angelo Dureghello <adureghello@xxxxxxxxxxxx> wrote:

> From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
>
> Extracting common code, to share common code to be used later
> by the AXI driver version (ad3552r-axi.c).
>
> Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>

Looks like a few arrays are now duplicated that probably shouldn't be.
Otherwise, just trivial comments inline.

Jonathan


> ---
> drivers/iio/dac/Makefile | 2 +-
> drivers/iio/dac/ad3552r-common.c | 163 +++++++++++++++++++++++
> drivers/iio/dac/ad3552r.c | 276 ++++-----------------------------------
> drivers/iio/dac/ad3552r.h | 199 ++++++++++++++++++++++++++++
> 4 files changed, 389 insertions(+), 251 deletions(-)
>
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index 2cf148f16306..56a125f56284 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -4,7 +4,7 @@
> #
>
> # When adding new entries keep the list in alphabetical order
> -obj-$(CONFIG_AD3552R) += ad3552r.o
> +obj-$(CONFIG_AD3552R) += ad3552r.o ad3552r-common.o
> obj-$(CONFIG_AD5360) += ad5360.o
> obj-$(CONFIG_AD5380) += ad5380.o
> obj-$(CONFIG_AD5421) += ad5421.o
> diff --git a/drivers/iio/dac/ad3552r-common.c b/drivers/iio/dac/ad3552r-common.c
> new file mode 100644
> index 000000000000..c8ccfbe2e95e
> --- /dev/null
> +++ b/drivers/iio/dac/ad3552r-common.c
> @@ -0,0 +1,163 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +//
> +// Copyright (c) 2010-2024 Analog Devices Inc.
> +// Copyright (c) 2024 Baylibre, SAS
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include "ad3552r.h"
> +
> +static const s32 ad3552r_ch_ranges[][2] = {
> + [AD3552R_CH_OUTPUT_RANGE_0__2P5V] = {0, 2500},

Please add spaces after { and before } given the code
is moving anyway and that's my preferred style (I'm getting fussier
about it over time :)


> + [AD3552R_CH_OUTPUT_RANGE_0__5V] = {0, 5000},
> + [AD3552R_CH_OUTPUT_RANGE_0__10V] = {0, 10000},
> + [AD3552R_CH_OUTPUT_RANGE_NEG_5__5V] = {-5000, 5000},
> + [AD3552R_CH_OUTPUT_RANGE_NEG_10__10V] = {-10000, 10000}
> +};
> +
> +static const s32 ad3542r_ch_ranges[][2] = {
> + [AD3542R_CH_OUTPUT_RANGE_0__2P5V] = {0, 2500},
> + [AD3542R_CH_OUTPUT_RANGE_0__3V] = {0, 3000},
> + [AD3542R_CH_OUTPUT_RANGE_0__5V] = {0, 5000},
> + [AD3542R_CH_OUTPUT_RANGE_0__10V] = {0, 10000},
> + [AD3542R_CH_OUTPUT_RANGE_NEG_2P5__7P5V] = {-2500, 7500},
> + [AD3542R_CH_OUTPUT_RANGE_NEG_5__5V] = {-5000, 5000}
> +};
> +
> +void ad3552r_calc_custom_gain(u8 p, u8 n, s16 goffs, u16 *reg)

return a u16 instead of passing it in as a pointer.
Fits better with how it is used I think.

> +{
> + *reg = FIELD_PREP(AD3552R_MASK_CH_RANGE_OVERRIDE, 1);
> + *reg |= FIELD_PREP(AD3552R_MASK_CH_GAIN_SCALING_P, p);
> + *reg |= FIELD_PREP(AD3552R_MASK_CH_GAIN_SCALING_N, n);
> + *reg |= FIELD_PREP(AD3552R_MASK_CH_OFFSET_BIT_8, abs((s32)goffs) >> 8);
> + *reg |= FIELD_PREP(AD3552R_MASK_CH_OFFSET_POLARITY, (s32)goffs < 0);
> +}
> +
> +int ad3552r_get_ref_voltage(struct device *dev, u32 *val)
> +{
> + int voltage, delta = 100000;

Trivial: Don't mix declarations with assignment and ones with out on same line.
It's slightly trickier to read. This driver currently does this
a lot but lets not introduce more cases.


> +
> + voltage = devm_regulator_get_enable_read_voltage(dev, "vref");
> + if (voltage < 0 && voltage != -ENODEV)
> + return dev_err_probe(dev, voltage,
> + "Error getting vref voltage\n");
> +
> + if (voltage == -ENODEV) {
> + if (device_property_read_bool(dev, "adi,vref-out-en"))
> + *val = AD3552R_INTERNAL_VREF_PIN_2P5V;
If val fits nicely into 31 bits and hence the positive values, I'd
return it as then these all become
return AD...

> + else
> + *val = AD3552R_INTERNAL_VREF_PIN_FLOATING;
> + } else {
and this else is then unnecessary.

> + if (voltage > 2500000 + delta || voltage < 2500000 - delta) {
> + dev_warn(dev, "vref-supply must be 2.5V");
> + return -EINVAL;
> + }
> + *val = AD3552R_EXTERNAL_VREF_PIN_INPUT;
> + }
> +
> + return 0;
> +}
> +
> +int ad3552r_get_drive_strength(struct device *dev, u32 *val)
> +{
> + int err;
> +
> + err = device_property_read_u32(dev, "adi,sdo-drive-strength", val);
> + if (!err && *val > 3) {
> + dev_err(dev,
> + "adi,sdo-drive-strength must be less than 4\n");
> + return -EINVAL;
if (err)
return err;

if (*val > 3) {
dev_err(dev,
"adi,sdo-drive-strength must be less than 4\n");
return -EINVAL;
}

return 0;

is a bit longer but keeps the error handling well separated from the
good path.

> + }
> +
> + return err;
> +}
> +

> +int ad3552r_get_output_range(struct device *dev, enum ad3552r_id chip_id,
> + struct fwnode_handle *child, u32 *val)
> +{
> + int ret;
> + s32 vals[2];
> +
> + if (!fwnode_property_present(child, "adi,output-range-microvolt"))
> + return -ENOENT;

Maybe add a comment that this property is optional, so we want to distinguish
this particular reason for failure. Took me a few mins to figure out why
we needed this check.


> +
> + ret = fwnode_property_read_u32_array(child,
> + "adi,output-range-microvolt",
> + vals, 2);
> + if (ret)
> + return dev_err_probe(dev, ret,
> + "invalid adi,output-range-microvolt\n");
> +
> + ret = ad3552r_find_range(chip_id, vals);
> + if (ret < 0)
> + return dev_err_probe(dev, ret,
> + "invalid adi,output-range-microvolt value\n");
> +
> + *val = ret;
> +
> + return 0;
> +}
> diff --git a/drivers/iio/dac/ad3552r.c b/drivers/iio/dac/ad3552r.c
> index d867de7c90d1..c149be9c8c7d 100644
> --- a/drivers/iio/dac/ad3552r.c
> +++ b/drivers/iio/dac/ad3552r.c
> @@ -11,153 +11,9 @@

> -enum ad3552r_ch_output_range {
> - /* Range from 0 V to 2.5 V. Requires Rfb1x connection */
> - AD3552R_CH_OUTPUT_RANGE_0__2P5V,
> - /* Range from 0 V to 5 V. Requires Rfb1x connection */
> - AD3552R_CH_OUTPUT_RANGE_0__5V,
> - /* Range from 0 V to 10 V. Requires Rfb2x connection */
> - AD3552R_CH_OUTPUT_RANGE_0__10V,
> - /* Range from -5 V to 5 V. Requires Rfb2x connection */
> - AD3552R_CH_OUTPUT_RANGE_NEG_5__5V,
> - /* Range from -10 V to 10 V. Requires Rfb4x connection */
> - AD3552R_CH_OUTPUT_RANGE_NEG_10__10V,
> -};
> +#include "ad3552r.h"
>
> static const s32 ad3552r_ch_ranges[][2] = {

This exists now in ad3552-common.c as well as here which seems unlikely to be
what you want.

> [AD3552R_CH_OUTPUT_RANGE_0__2P5V] = {0, 2500},
> @@ -167,21 +23,6 @@ static const s32 ad3552r_ch_ranges[][2] = {
> [AD3552R_CH_OUTPUT_RANGE_NEG_10__10V] = {-10000, 10000}
> };
>
> -enum ad3542r_ch_output_range {
> - /* Range from 0 V to 2.5 V. Requires Rfb1x connection */
> - AD3542R_CH_OUTPUT_RANGE_0__2P5V,
> - /* Range from 0 V to 3 V. Requires Rfb1x connection */
> - AD3542R_CH_OUTPUT_RANGE_0__3V,
> - /* Range from 0 V to 5 V. Requires Rfb1x connection */
> - AD3542R_CH_OUTPUT_RANGE_0__5V,
> - /* Range from 0 V to 10 V. Requires Rfb2x connection */
> - AD3542R_CH_OUTPUT_RANGE_0__10V,
> - /* Range from -2.5 V to 7.5 V. Requires Rfb2x connection */
> - AD3542R_CH_OUTPUT_RANGE_NEG_2P5__7P5V,
> - /* Range from -5 V to 5 V. Requires Rfb2x connection */
> - AD3542R_CH_OUTPUT_RANGE_NEG_5__5V,
> -};
> -
> static const s32 ad3542r_ch_ranges[][2] = {

Isn't this in the new location above?

> [AD3542R_CH_OUTPUT_RANGE_0__2P5V] = {0, 2500},
> [AD3542R_CH_OUTPUT_RANGE_0__3V] = {0, 3000},
> @@ -733,72 +574,32 @@ static void ad3552r_calc_gain_and_offset(struct ad3552r_desc *dac, s32 ch)
> dac->ch_data[ch].offset_dec = div_s64(tmp, span);
> }
>

> static int ad3552r_configure_custom_gain(struct ad3552r_desc *dac,
> struct fwnode_handle *child,
> u32 ch)
> {
> struct device *dev = &dac->spi->dev;
> - u32 val;
> int err;
> u8 addr;
> - u16 reg = 0, offset;
> -
> - struct fwnode_handle *gain_child __free(fwnode_handle)
> - = fwnode_get_named_child_node(child,
> - "custom-output-range-config");
> - if (!gain_child)
> - return dev_err_probe(dev, -EINVAL,
> - "mandatory custom-output-range-config property missing\n");
> -
> - dac->ch_data[ch].range_override = 1;
> - reg |= FIELD_PREP(AD3552R_MASK_CH_RANGE_OVERRIDE, 1);
> -
> - err = fwnode_property_read_u32(gain_child, "adi,gain-scaling-p", &val);
> - if (err)
> - return dev_err_probe(dev, err,
> - "mandatory adi,gain-scaling-p property missing\n");
> - reg |= FIELD_PREP(AD3552R_MASK_CH_GAIN_SCALING_P, val);
> - dac->ch_data[ch].p = val;
> + u16 reg = 0;
>
> - err = fwnode_property_read_u32(gain_child, "adi,gain-scaling-n", &val);
> + err = ad3552r_get_custom_gain(dev, child,
> + &dac->ch_data[ch].p,
> + &dac->ch_data[ch].n,
> + &dac->ch_data[ch].rfb,
> + &dac->ch_data[ch].gain_offset);
> if (err)
> - return dev_err_probe(dev, err,
> - "mandatory adi,gain-scaling-n property missing\n");
> - reg |= FIELD_PREP(AD3552R_MASK_CH_GAIN_SCALING_N, val);
> - dac->ch_data[ch].n = val;
> -
> - err = fwnode_property_read_u32(gain_child, "adi,rfb-ohms", &val);
> - if (err)
> - return dev_err_probe(dev, err,
> - "mandatory adi,rfb-ohms property missing\n");
> - dac->ch_data[ch].rfb = val;
> + return err;
>
> - err = fwnode_property_read_u32(gain_child, "adi,gain-offset", &val);
> - if (err)
> - return dev_err_probe(dev, err,
> - "mandatory adi,gain-offset property missing\n");
> - dac->ch_data[ch].gain_offset = val;
> + dac->ch_data[ch].range_override = 1;
>
> - offset = abs((s32)val);
> - reg |= FIELD_PREP(AD3552R_MASK_CH_OFFSET_BIT_8, (offset >> 8));
> + ad3552r_calc_custom_gain(dac->ch_data[ch].p, dac->ch_data[ch].n,
> + dac->ch_data[ch].gain_offset, &reg);
>
> - reg |= FIELD_PREP(AD3552R_MASK_CH_OFFSET_POLARITY, (s32)val < 0);
> addr = AD3552R_REG_ADDR_CH_GAIN(ch);
> err = ad3552r_write_reg(dac, addr,

Given you now have the calculation of reg nice and compact, I'd move that after
this call. It's odd to calculate a value first then not use it whilst
doing some other stuff.

> - offset & AD3552R_MASK_CH_OFFSET_BITS_0_7);
> + abs((s32)dac->ch_data[ch].gain_offset) &
> + AD3552R_MASK_CH_OFFSET_BITS_0_7);
> if (err)
> return dev_err_probe(dev, err, "Error writing register\n");
>
> @@ -812,30 +613,17 @@ static int ad3552r_configure_custom_gain(struct ad3552r_desc *dac,
> static int ad3552r_configure_device(struct ad3552r_desc *dac)
> {
> struct device *dev = &dac->spi->dev;
> - int err, cnt = 0, voltage, delta = 100000;
> - u32 vals[2], val, ch;
> + int err, cnt = 0;
> + u32 val, ch;
>
> dac->gpio_ldac = devm_gpiod_get_optional(dev, "ldac", GPIOD_OUT_HIGH);
> if (IS_ERR(dac->gpio_ldac))
> return dev_err_probe(dev, PTR_ERR(dac->gpio_ldac),
> "Error getting gpio ldac");
>
> - voltage = devm_regulator_get_enable_read_voltage(dev, "vref");
> - if (voltage < 0 && voltage != -ENODEV)
> - return dev_err_probe(dev, voltage, "Error getting vref voltage\n");
> -
> - if (voltage == -ENODEV) {
> - if (device_property_read_bool(dev, "adi,vref-out-en"))
> - val = AD3552R_INTERNAL_VREF_PIN_2P5V;
> - else
> - val = AD3552R_INTERNAL_VREF_PIN_FLOATING;
> - } else {
> - if (voltage > 2500000 + delta || voltage < 2500000 - delta) {
> - dev_warn(dev, "vref-supply must be 2.5V");
> - return -EINVAL;
> - }
> - val = AD3552R_EXTERNAL_VREF_PIN_INPUT;
> - }
> + err = ad3552r_get_ref_voltage(dev, &val);
> + if (err)
> + return err;
With suggestion above,
err = ad3552_get_ref_voltage(dev);
if (err)
return err;

val = err;

>
> err = ad3552r_update_reg_field(dac,
> AD3552R_REG_ADDR_SH_REFERENCE_CONFIG,
...

> diff --git a/drivers/iio/dac/ad3552r.h b/drivers/iio/dac/ad3552r.h
> new file mode 100644
> index 000000000000..cada1f12f000
> --- /dev/null
> +++ b/drivers/iio/dac/ad3552r.h
> @@ -0,0 +1,199 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * AD3552R Digital <-> Analog converters common header
> + *
> + * Copyright 2024 Analog Devices Inc.
> + * Author: Angelo Dureghello <adureghello@xxxxxxxxxxxx>

It's all code lifted from elsewhere, so keep the original
2021 date as well. 2021-2024 would be fine.

> + */
...