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([2600:8803:e7e4:1d00:1120:d1cf:c64a:ac7e]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-2dba061c18fsm156268fac.9.2025.05.08.10.08.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 May 2025 10:08:31 -0700 (PDT) Message-ID: <4fb74419-51bf-4294-82bf-545504ad0c3f@baylibre.com> Date: Thu, 8 May 2025 12:08:30 -0500 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/4] iio: adc: ad7405: add ad7405 driver To: Pop Ioan Daniel , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , =?UTF-8?Q?Nuno_S=C3=A1?= , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sergiu Cuciurean , Dragos Bogdan , Antoniu Miclaus , Olivier Moysan , Javier Carrasco , Matti Vaittinen , Tobias Sperling , Alisa-Dariana Roman , Marcelo Schmitt , Matteo Martelli , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250508123107.3797042-1-pop.ioan-daniel@analog.com> <20250508123107.3797042-5-pop.ioan-daniel@analog.com> From: David Lechner Content-Language: en-US In-Reply-To: <20250508123107.3797042-5-pop.ioan-daniel@analog.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/8/25 7:30 AM, Pop Ioan Daniel wrote: > Add support for the AD7405/ADUM770x, a high performance isolated ADC, > 1-channel, 16-bit with a second-order Σ-Δ modulator that converts an > analog input signal into a high speed, single-bit data stream. > > Signed-off-by: Pop Ioan Daniel > --- ... > diff --git a/drivers/iio/adc/ad7405.c b/drivers/iio/adc/ad7405.c > new file mode 100644 > index 000000000000..5fe36ce61819 > --- /dev/null > +++ b/drivers/iio/adc/ad7405.c > @@ -0,0 +1,264 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Analog Devices AD7405 driver > + * > + * Copyright 2025 Analog Devices Inc. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > + > +const unsigned int ad7405_dec_rates[] = { > + 4096, 2048, 1024, 512, 256, 128, 64, 32, > +}; > + > +struct ad7405_chip_info { > + const char *name; > + unsigned int max_rate; > + struct iio_chan_spec channel[]; Since there is only one channel, we can drop the [] here. > +}; > + > +struct ad7405_state { > + struct iio_backend *back; > + /* lock to protect multiple accesses to the device registers */ > + struct mutex lock; This lock isn't used and can be removed. > + const struct ad7405_chip_info *info; > + unsigned int sample_frequency_tbl[ARRAY_SIZE(ad7405_dec_rates)]; > + unsigned int sample_frequency; > + unsigned int ref_frequency; > +}; > + > +static void ad7405_fill_samp_freq_table(struct ad7405_state *st) > +{ > + unsigned int i; > + > + for (i = 0; i < ARRAY_SIZE(ad7405_dec_rates); i++) > + st->sample_frequency_tbl[i] = > + DIV_ROUND_CLOSEST_ULL(st->ref_frequency, ad7405_dec_rates[i]); > +} > + > +static int ad7405_set_sampling_rate(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + unsigned int samp_rate) > +{ > + struct ad7405_state *st = iio_priv(indio_dev); > + unsigned int dec_rate, idx; > + int ret; > + > + dec_rate = DIV_ROUND_CLOSEST_ULL(st->ref_frequency, samp_rate); > + > + idx = find_closest_descending(dec_rate, ad7405_dec_rates, > + ARRAY_SIZE(ad7405_dec_rates)); > + > + dec_rate = ad7405_dec_rates[idx]; > + > + ret = iio_backend_oversampling_ratio_set(st->back, 0, dec_rate); > + if (ret) > + return ret; > + > + st->sample_frequency = DIV_ROUND_CLOSEST_ULL(st->ref_frequency, dec_rate); > + > + return 0; > +} > + > +static int ad7405_read_raw(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, int *val, > + int *val2, long info) > +{ > + struct ad7405_state *st = iio_priv(indio_dev); > + > + switch (info) { This is missing an implementation for IIO_CHAN_INFO_SCALE and IIO_CHAN_INFO_OFFSET. > + case IIO_CHAN_INFO_SAMP_FREQ: > + *val = st->sample_frequency; > + return IIO_VAL_INT; > + default: > + return -EINVAL; > + } > +} > + > +static int ad7405_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, int val, > + int val2, long info) > +{ > + switch (info) { > + case IIO_CHAN_INFO_SAMP_FREQ: > + if (val < 1) > + return -EINVAL; > + return ad7405_set_sampling_rate(indio_dev, chan, val); > + default: > + return -EINVAL; > + } > +} > + > +static int ad7405_read_avail(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + const int **vals, int *type, int *length, > + long info) > +{ > + struct ad7405_state *st = iio_priv(indio_dev); > + > + switch (info) { > + case IIO_CHAN_INFO_SAMP_FREQ: > + *vals = st->sample_frequency_tbl; > + *length = ARRAY_SIZE(st->sample_frequency_tbl); > + *type = IIO_VAL_INT; > + return IIO_AVAIL_LIST; > + default: > + return -EINVAL; > + } > +} > + > +static void ad7405_clk_disable_unprepare(void *clk) > +{ > + clk_disable_unprepare(clk); > +} > + > +static const struct iio_info ad7405_iio_info = { > + .read_raw = &ad7405_read_raw, > + .write_raw = &ad7405_write_raw, > + .read_avail = &ad7405_read_avail, > +}; > + > +#define AD7405_IIO_CHANNEL { \ > + .type = IIO_VOLTAGE, \ > + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \ > + .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ), \ Would it make more sense to use IIO_CHAN_INFO_OVERSAMPLING_RATIO for controlling the decimation rate and have IIO_CHAN_INFO_SAMP_FREQ be read-only? Maybe also useful to have a read-only filter_type attribute to say that the backend is providing a sinc3 filter? > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ > + BIT(IIO_CHAN_INFO_OFFSET), \ > + .indexed = 1, \ > + .channel = 0, \ > + .channel2 = 1, \ > + .differential = 1, \ > + .scan_index = 0, \ > + .scan_type = { \ > + .sign = 'u', \ > + .realbits = 16, \ > + .storagebits = 16, \ > + }, \ > +} > + > +static const struct ad7405_chip_info ad7405_chip_info = { > + .name = "AD7405", > + .channel = { > + AD7405_IIO_CHANNEL, > + }, > +}; > + > +static const struct ad7405_chip_info adum7701_chip_info = { > + .name = "ADUM7701", > + .channel = { > + AD7405_IIO_CHANNEL, > + }, > +}; > + > +static const char * const ad7405_power_supplies[] = { > + "vdd1", "vdd2", > +}; > + > +static int ad7405_probe(struct platform_device *pdev) > +{ > + const struct ad7405_chip_info *chip_info; > + struct device *dev = &pdev->dev; > + struct iio_dev *indio_dev; > + struct ad7405_state *st; > + struct clk *clk; > + int ret; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + st = iio_priv(indio_dev); > + > + ret = devm_mutex_init(dev, &st->lock); > + if (ret) > + return ret; > + > + chip_info = device_get_match_data(dev); > + if (!chip_info) > + return dev_err_probe(dev, -EINVAL, "no chip info\n"); > + > + ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad7405_power_supplies), > + ad7405_power_supplies); > + > + if (ret) > + return dev_err_probe(dev, ret, "failed to get and enable supplies"); > + > + clk = devm_clk_get_enabled(dev, NULL); > + if (IS_ERR(clk)) > + return PTR_ERR(clk); > + > + ret = devm_add_action_or_reset(dev, ad7405_clk_disable_unprepare, clk); devm_clk_get_enabled() already make sure the clock is disabled when the dirver is removed, so this is not needed. > + if (ret) > + return ret; > + > + st->ref_frequency = clk_get_rate(clk); > + if (!(st->ref_frequency)) Inner () not needed. > + return -EINVAL; > + > + ad7405_fill_samp_freq_table(st); > + > + indio_dev->dev.parent = dev; > + indio_dev->name = chip_info->name; > + indio_dev->channels = chip_info->channel; > + indio_dev->num_channels = 1; > + indio_dev->info = &ad7405_iio_info; > + > + st->back = devm_iio_backend_get(dev, NULL); > + if (IS_ERR(st->back)) > + return dev_err_probe(dev, PTR_ERR(st->back), > + "failed to get IIO backend"); > + > + ret = iio_backend_chan_enable(st->back, 0); > + if (ret) > + return ret; > + > + 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; > + > + ret = ad7405_set_sampling_rate(indio_dev, &indio_dev->channels[0], > + chip_info->max_rate); max_rate is never set, so will always be 0. > + if (ret) > + return ret; > + > + return devm_iio_device_register(dev, indio_dev); > +} > + > +/* Match table for of_platform binding */ > +static const struct of_device_id ad7405_of_match[] = { > + { .compatible = "adi,ad7405", .data = &ad7405_chip_info, }, > + { .compatible = "adi,adum7701", .data = &adum7701_chip_info, }, > + { .compatible = "adi,adum7702", .data = &adum7701_chip_info, }, > + { .compatible = "adi,adum7703", .data = &adum7701_chip_info, }, > + { /* end of list */ }, { } We standardized on this style in the IIO subsystem. > +}; > +MODULE_DEVICE_TABLE(of, ad7405_of_match); > + > +static struct platform_driver ad7405_driver = { > + .driver = { > + .name = "ad7405", > + .owner = THIS_MODULE, > + .of_match_table = ad7405_of_match, > + }, > + .probe = ad7405_probe, > +}; > +module_platform_driver(ad7405_driver); > + > +MODULE_AUTHOR("Dragos Bogdan "); > +MODULE_AUTHOR("Pop Ioan Daniel "); > +MODULE_DESCRIPTION("Analog Devices AD7405 driver"); > +MODULE_LICENSE("GPL"); > +MODULE_IMPORT_NS("IIO_BACKEND");