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Message-ID: <a6bee0f1-3b06-44d6-9592-ab7f04a3ffcd@baylibre.com>
Date: Fri, 18 Oct 2024 16:07:18 +0200
From: Guillaume Stols <gstols@...libre.com>
To: Uwe Kleine-König <ukleinek@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Michael Hennerich <Michael.Hennerich@...log.com>,
Jonathan Cameron <jic23@...nel.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
<conor+dt@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>, Jonathan Corbet <corbet@....net>
Cc: linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-fbdev@...r.kernel.org, linux-iio@...r.kernel.org,
devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
aardelean@...libre.com, dlechner@...libre.com, jstephan@...libre.com,
nuno.sa@...log.com, Jonathan Cameron <Jonathan.Cameron@...wei.com>
Subject: Re: [PATCH v5 7/8] iio: adc: ad7606: Add iio-backend support
On 10/15/24 15:56, Guillaume Stols wrote:
> - Basic support for iio backend.
> - Supports IIO_CHAN_INFO_SAMP_FREQ R/W.
> - Only hardware mode is available, and that IIO_CHAN_INFO_RAW is not
> supported if iio-backend mode is selected.
>
> Signed-off-by: Guillaume Stols <gstols@...libre.com>
> ---
> drivers/iio/adc/Kconfig | 2 +
> drivers/iio/adc/ad7606.c | 154 ++++++++++++++++++++++++++++++++++---------
> drivers/iio/adc/ad7606.h | 15 +++++
> drivers/iio/adc/ad7606_par.c | 92 +++++++++++++++++++++++++-
> 4 files changed, 231 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 91873f60322d..a57b5f0bc070 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -224,9 +224,11 @@ config AD7606_IFACE_PARALLEL
> tristate "Analog Devices AD7606 ADC driver with parallel interface support"
> depends on HAS_IOPORT
> select AD7606
> + select IIO_BACKEND
> help
> Say yes here to build parallel interface support for Analog Devices:
> ad7605-4, ad7606, ad7606-6, ad7606-4 analog to digital converters (ADC).
> + It also support iio_backended devices for AD7606B.
>
> To compile this driver as a module, choose M here: the
> module will be called ad7606_par.
> diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
> index 34d377e9ac79..7871552ce5ac 100644
> --- a/drivers/iio/adc/ad7606.c
> +++ b/drivers/iio/adc/ad7606.c
> @@ -21,6 +21,7 @@
> #include <linux/units.h>
> #include <linux/util_macros.h>
>
> +#include <linux/iio/backend.h>
> #include <linux/iio/buffer.h>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> @@ -191,6 +192,7 @@ EXPORT_SYMBOL_NS_GPL(ad7606_4_info, IIO_AD7606);
>
> const struct ad7606_chip_info ad7606b_info = {
> .channels = ad7606_channels_16bit,
> + .max_samplerate = 800 * KILO,
> .name = "ad7606b",
> .num_adc_channels = 8,
> .num_channels = 9,
> @@ -490,6 +492,17 @@ static int ad7606_pwm_set_low(struct ad7606_state *st)
> return ret;
> }
>
> +static int ad7606_pwm_set_swing(struct ad7606_state *st)
> +{
> + struct pwm_state cnvst_pwm_state;
> +
> + pwm_get_state(st->cnvst_pwm, &cnvst_pwm_state);
> + cnvst_pwm_state.enabled = true;
> + cnvst_pwm_state.duty_cycle = cnvst_pwm_state.period / 2;
> +
> + return pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state);
> +}
> +
> static bool ad7606_pwm_is_swinging(struct ad7606_state *st)
> {
> struct pwm_state cnvst_pwm_state;
> @@ -576,11 +589,22 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch,
> if (ret < 0)
> return ret;
> }
> - ret = wait_for_completion_timeout(&st->completion,
> - msecs_to_jiffies(1000));
> - if (!ret) {
> - ret = -ETIMEDOUT;
> - goto error_ret;
> +
> + /*
> + * If no backend, wait for the interruption on busy pin, otherwise just add
> + * a delay to leave time for the data to be available. For now, the latter
> + * will not happen because IIO_CHAN_INFO_RAW is not supported for the backend.
> + * TODO: Add support for reading a single value when the backend is used.
> + */
> + if (!st->back) {
> + ret = wait_for_completion_timeout(&st->completion,
> + msecs_to_jiffies(1000));
> + if (!ret) {
> + ret = -ETIMEDOUT;
> + goto error_ret;
> + }
> + } else {
> + fsleep(1);
> }
>
> ret = ad7606_read_samples(st);
> @@ -620,6 +644,7 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
> int ret, ch = 0;
> struct ad7606_state *st = iio_priv(indio_dev);
> struct ad7606_chan_scale *cs;
> + struct pwm_state cnvst_pwm_state;
>
> switch (m) {
> case IIO_CHAN_INFO_RAW:
> @@ -640,6 +665,14 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
> case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> *val = st->oversampling;
> return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + /*
> + * TODO: return the real frequency intead of the requested one once
> + * pwm_get_state_hw comes upstream.
> + */
> + pwm_get_state(st->cnvst_pwm, &cnvst_pwm_state);
> + *val = DIV_ROUND_CLOSEST_ULL(NSEC_PER_SEC, cnvst_pwm_state.period);
> + return IIO_VAL_INT;
> }
> return -EINVAL;
> }
> @@ -732,6 +765,10 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
> return ret;
>
> return 0;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + if (val < 0 && val2 != 0)
> + return -EINVAL;
> + return ad7606_set_sampling_freq(st, val);
> default:
> return -EINVAL;
> }
> @@ -914,14 +951,50 @@ static int ad7606_read_avail(struct iio_dev *indio_dev,
> return -EINVAL;
> }
>
> +static int ad7606_backend_buffer_postenable(struct iio_dev *indio_dev)
> +{
> + struct ad7606_state *st = iio_priv(indio_dev);
> +
> + return ad7606_pwm_set_swing(st);
> +}
> +
> +static int ad7606_backend_buffer_predisable(struct iio_dev *indio_dev)
> +{
> + struct ad7606_state *st = iio_priv(indio_dev);
> +
> + return ad7606_pwm_set_low(st);
> +}
> +
> +static int ad7606_update_scan_mode(struct iio_dev *indio_dev,
> + const unsigned long *scan_mask)
> +{
> + struct ad7606_state *st = iio_priv(indio_dev);
> +
> + /*
> + * The update scan mode is only for iio backend compatible drivers.
> + * If the specific update_scan_mode is not defined in the bus ops,
> + * just do nothing and return 0.
> + */
> + if (!st->bops->update_scan_mode)
> + return 0;
> +
> + return st->bops->update_scan_mode(indio_dev, scan_mask);
> +}
> +
> static const struct iio_buffer_setup_ops ad7606_buffer_ops = {
> .postenable = &ad7606_buffer_postenable,
> .predisable = &ad7606_buffer_predisable,
> };
>
> +static const struct iio_buffer_setup_ops ad7606_backend_buffer_ops = {
> + .postenable = &ad7606_backend_buffer_postenable,
> + .predisable = &ad7606_backend_buffer_predisable,
> +};
> +
> static const struct iio_info ad7606_info_no_os_or_range = {
> .read_raw = &ad7606_read_raw,
> .validate_trigger = &ad7606_validate_trigger,
> + .update_scan_mode = &ad7606_update_scan_mode,
> };
>
> static const struct iio_info ad7606_info_os_and_range = {
> @@ -929,6 +1002,7 @@ static const struct iio_info ad7606_info_os_and_range = {
> .write_raw = &ad7606_write_raw,
> .attrs = &ad7606_attribute_group_os_and_range,
> .validate_trigger = &ad7606_validate_trigger,
> + .update_scan_mode = &ad7606_update_scan_mode,
> };
>
> static const struct iio_info ad7606_info_sw_mode = {
> @@ -937,6 +1011,7 @@ static const struct iio_info ad7606_info_sw_mode = {
> .read_avail = &ad7606_read_avail,
> .debugfs_reg_access = &ad7606_reg_access,
> .validate_trigger = &ad7606_validate_trigger,
> + .update_scan_mode = &ad7606_update_scan_mode,
> };
>
> static const struct iio_info ad7606_info_os = {
> @@ -944,6 +1019,7 @@ static const struct iio_info ad7606_info_os = {
> .write_raw = &ad7606_write_raw,
> .attrs = &ad7606_attribute_group_os,
> .validate_trigger = &ad7606_validate_trigger,
> + .update_scan_mode = &ad7606_update_scan_mode,
> };
>
> static const struct iio_info ad7606_info_range = {
> @@ -951,6 +1027,7 @@ static const struct iio_info ad7606_info_range = {
> .write_raw = &ad7606_write_raw,
> .attrs = &ad7606_attribute_group_range,
> .validate_trigger = &ad7606_validate_trigger,
> + .update_scan_mode = &ad7606_update_scan_mode,
> };
>
> static const struct iio_trigger_ops ad7606_trigger_ops = {
> @@ -1070,8 +1147,6 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
> indio_dev->channels = st->chip_info->channels;
> indio_dev->num_channels = st->chip_info->num_channels;
>
> - init_completion(&st->completion);
> -
> ret = ad7606_reset(st);
> if (ret)
> dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
> @@ -1118,34 +1193,51 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
> if (ret)
> return ret;
> }
> - st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
> - indio_dev->name,
> - iio_device_id(indio_dev));
> - if (!st->trig)
> - return -ENOMEM;
>
> - st->trig->ops = &ad7606_trigger_ops;
> - iio_trigger_set_drvdata(st->trig, indio_dev);
> - ret = devm_iio_trigger_register(dev, st->trig);
> - if (ret)
> - return ret;
> + if (st->bops->iio_backend_config) {
> + /*
> + * If there is a backend, the PWM should not overpass the maximum sampling
> + * frequency the chip supports.
> + */
> + ret = ad7606_set_sampling_freq(st,
> + chip_info->max_samplerate ? : 2 * KILO);
> + if (ret)
> + return ret;
> +
> + ret = st->bops->iio_backend_config(dev, indio_dev);
> + if (ret)
> + return ret;
>
> - indio_dev->trig = iio_trigger_get(st->trig);
> + indio_dev->setup_ops = &ad7606_backend_buffer_ops;
> + } else {
> + init_completion(&st->completion);
> + st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
> + indio_dev->name,
> + iio_device_id(indio_dev));
> + if (!st->trig)
> + return -ENOMEM;
> +
> + st->trig->ops = &ad7606_trigger_ops;
> + iio_trigger_set_drvdata(st->trig, indio_dev);
> + ret = devm_iio_trigger_register(dev, st->trig);
> + if (ret)
> + return ret;
>
> - ret = devm_request_threaded_irq(dev, irq,
> - NULL,
> - &ad7606_interrupt,
> - IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> - chip_info->name, indio_dev);
> - if (ret)
> - return ret;
> + indio_dev->trig = iio_trigger_get(st->trig);
>
> - ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
> - &iio_pollfunc_store_time,
> - &ad7606_trigger_handler,
> - &ad7606_buffer_ops);
> - if (ret)
> - return ret;
> + ret = devm_request_threaded_irq(dev, irq, NULL, &ad7606_interrupt,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + chip_info->name, indio_dev);
> + if (ret)
> + return ret;
> +
> + ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
> + &iio_pollfunc_store_time,
> + &ad7606_trigger_handler,
> + &ad7606_buffer_ops);
> + if (ret)
> + return ret;
> + }
>
> return devm_iio_device_register(dev, indio_dev);
> }
> diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
> index b26a11b2eba1..2c629a15cc33 100644
> --- a/drivers/iio/adc/ad7606.h
> +++ b/drivers/iio/adc/ad7606.h
> @@ -61,6 +61,12 @@
>
> #define AD7616_CHANNEL(num) AD7606_SW_CHANNEL(num, 16)
>
> +#define AD7606_BI_CHANNEL(num) \
> + AD760X_CHANNEL(num, 0, \
> + BIT(IIO_CHAN_INFO_SCALE), \
> + BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), 16)
> +
> struct ad7606_state;
>
> typedef int (*ad7606_scale_setup_cb_t)(struct ad7606_state *st,
> @@ -69,6 +75,7 @@ typedef int (*ad7606_scale_setup_cb_t)(struct ad7606_state *st,
> /**
> * struct ad7606_chip_info - chip specific information
> * @channels: channel specification
> + * @max_samplerate: maximum supported samplerate
> * @name device name
> * @num_channels: number of channels
> * @num_adc_channels the number of channels the ADC actually inputs.
> @@ -82,6 +89,7 @@ typedef int (*ad7606_scale_setup_cb_t)(struct ad7606_state *st,
> */
> struct ad7606_chip_info {
> const struct iio_chan_spec *channels;
> + unsigned int max_samplerate;
> const char *name;
> unsigned int num_adc_channels;
> unsigned int num_channels;
> @@ -152,6 +160,7 @@ struct ad7606_state {
> bool sw_mode_en;
> const unsigned int *oversampling_avail;
> unsigned int num_os_ratios;
> + struct iio_backend *back;
> int (*write_scale)(struct iio_dev *indio_dev, int ch, int val);
> int (*write_os)(struct iio_dev *indio_dev, int val);
>
> @@ -180,16 +189,21 @@ struct ad7606_state {
>
> /**
> * struct ad7606_bus_ops - driver bus operations
> + * @iio_backend_config function pointer for configuring the iio_backend for
> + * the compatibles that use it
> * @read_block function pointer for reading blocks of data
> * @sw_mode_config: pointer to a function which configured the device
> * for software mode
> * @reg_read function pointer for reading spi register
> * @reg_write function pointer for writing spi register
> * @write_mask function pointer for write spi register with mask
> + * @update_scan_mode function pointer for handling the calls to iio_info's update_scan
> + * mode when enabling/disabling channels.
> * @rd_wr_cmd pointer to the function which calculates the spi address
> */
> struct ad7606_bus_ops {
> /* more methods added in future? */
> + int (*iio_backend_config)(struct device *dev, struct iio_dev *indio_dev);
> int (*read_block)(struct device *dev, int num, void *data);
> int (*sw_mode_config)(struct iio_dev *indio_dev);
> int (*reg_read)(struct ad7606_state *st, unsigned int addr);
> @@ -200,6 +214,7 @@ struct ad7606_bus_ops {
> unsigned int addr,
> unsigned long mask,
> unsigned int val);
> + int (*update_scan_mode)(struct iio_dev *indio_dev, const unsigned long *scan_mask);
> u16 (*rd_wr_cmd)(int addr, char isWriteOp);
> };
>
> diff --git a/drivers/iio/adc/ad7606_par.c b/drivers/iio/adc/ad7606_par.c
> index b87be2f1ca04..6946ff00e4cb 100644
> --- a/drivers/iio/adc/ad7606_par.c
> +++ b/drivers/iio/adc/ad7606_par.c
> @@ -2,7 +2,8 @@
> /*
> * AD7606 Parallel Interface ADC driver
> *
> - * Copyright 2011 Analog Devices Inc.
> + * Copyright 2011 - 2024 Analog Devices Inc.
> + * Copyright 2024 BayLibre SAS.
> */
>
> #include <linux/err.h>
> @@ -14,9 +15,82 @@
> #include <linux/property.h>
> #include <linux/types.h>
>
> +#include <linux/iio/backend.h>
> #include <linux/iio/iio.h>
> +
> #include "ad7606.h"
>
> +static const struct iio_chan_spec ad7606b_bi_channels[] = {
> + AD7606_BI_CHANNEL(0),
> + AD7606_BI_CHANNEL(1),
> + AD7606_BI_CHANNEL(2),
> + AD7606_BI_CHANNEL(3),
> + AD7606_BI_CHANNEL(4),
> + AD7606_BI_CHANNEL(5),
> + AD7606_BI_CHANNEL(6),
> + AD7606_BI_CHANNEL(7),
> +};
> +
> +static int ad7606_bi_update_scan_mode(struct iio_dev *indio_dev, const unsigned long *scan_mask)
> +{
> + struct ad7606_state *st = iio_priv(indio_dev);
> + unsigned int c, ret;
> +
> + for (c = 0; c < indio_dev->num_channels; c++) {
> + if (test_bit(c, scan_mask))
> + ret = iio_backend_chan_enable(st->back, c);
> + else
> + ret = iio_backend_chan_disable(st->back, c);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int ad7606_bi_setup_iio_backend(struct device *dev, struct iio_dev *indio_dev)
> +{
> + struct ad7606_state *st = iio_priv(indio_dev);
> + unsigned int ret, c;
> + struct iio_backend_data_fmt data = {
> + .sign_extend = true,
> + .enable = true,
> + };
> +
> + st->back = devm_iio_backend_get(dev, NULL);
> + if (IS_ERR(st->back))
> + return PTR_ERR(st->back);
> +
> + /* If the device is iio_backend powered the PWM is mandatory */
> + if (!st->cnvst_pwm)
> + return dev_err_probe(st->dev, -EINVAL,
> + "A PWM is mandatory when using backend.\n");
> +
> + ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
> + if (ret)
> + return ret;
> +
> + ret = devm_iio_backend_enable(dev, st->back);
> + if (ret)
> + return ret;
> +
> + for (c = 0; c < indio_dev->num_channels; c++) {
> + ret = iio_backend_data_format_set(st->back, c, &data);
> + if (ret)
> + return ret;
> + }
> +
> + indio_dev->channels = ad7606b_bi_channels;
> + indio_dev->num_channels = 8;
> +
> + return 0;
> +}
> +
> +static const struct ad7606_bus_ops ad7606_bi_bops = {
> + .iio_backend_config = ad7606_bi_setup_iio_backend,
> + .update_scan_mode = ad7606_bi_update_scan_mode,
> +};
> +
> static int ad7606_par16_read_block(struct device *dev,
> int count, void *buf)
> {
> @@ -96,9 +170,22 @@ static int ad7606_par_probe(struct platform_device *pdev)
> void __iomem *addr;
> resource_size_t remap_size;
> int irq;
> + struct iio_backend *back;
Just spotted that I forgot to remove the declaration. Shall I send
another series with this correction ?
>
> + /*
> + * If a firmware node is available (ACPI or DT), platform_device_id is null
> + * and we must use get_match_data.
> + */
> if (dev_fwnode(&pdev->dev)) {
> chip_info = device_get_match_data(&pdev->dev);
> + if (device_property_present(&pdev->dev, "io-backends"))
> + /*
> + * If a backend is available ,call the core probe with backend
> + * bops, otherwise use the former bops.
> + */
> + return ad7606_probe(&pdev->dev, 0, NULL,
> + chip_info,
> + &ad7606_bi_bops);
> } else {
> id = platform_get_device_id(pdev);
> chip_info = (const struct ad7606_chip_info *)id->driver_data;
> @@ -124,6 +211,7 @@ static const struct platform_device_id ad7606_driver_ids[] = {
> { .name = "ad7606-4", .driver_data = (kernel_ulong_t)&ad7606_4_info, },
> { .name = "ad7606-6", .driver_data = (kernel_ulong_t)&ad7606_6_info, },
> { .name = "ad7606-8", .driver_data = (kernel_ulong_t)&ad7606_8_info, },
> + { .name = "ad7606b", .driver_data = (kernel_ulong_t)&ad7606b_info, },
> { }
> };
> MODULE_DEVICE_TABLE(platform, ad7606_driver_ids);
> @@ -133,6 +221,7 @@ static const struct of_device_id ad7606_of_match[] = {
> { .compatible = "adi,ad7606-4", .data = &ad7606_4_info },
> { .compatible = "adi,ad7606-6", .data = &ad7606_6_info },
> { .compatible = "adi,ad7606-8", .data = &ad7606_8_info },
> + { .compatible = "adi,ad7606b", .data = &ad7606b_info },
> { }
> };
> MODULE_DEVICE_TABLE(of, ad7606_of_match);
> @@ -152,3 +241,4 @@ MODULE_AUTHOR("Michael Hennerich <michael.hennerich@...log.com>");
> MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
> MODULE_LICENSE("GPL v2");
> MODULE_IMPORT_NS(IIO_AD7606);
> +MODULE_IMPORT_NS(IIO_BACKEND);
>
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