On Wed, Jun 14, 2023 at 3:49 AM Kim Seer Paller <kimseer.paller@xxxxxxxxxx> wrote: > > The MAX14001 is configurable, isolated 10-bit ADCs for multi-range > binary inputs. Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> One question below. > Signed-off-by: Kim Seer Paller <kimseer.paller@xxxxxxxxxx> > --- > V5 -> V6: Replaced fixed length assignment with dynamic size > assignment in xfers struct initialization. Removed .channel > assignment in max14001_channels definition. > V4 -> V5: No changes. > V3 -> V4: Removed regmap setup, structures, and include. > > MAINTAINERS | 1 + > drivers/iio/adc/Kconfig | 10 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/max14001.c | 327 +++++++++++++++++++++++++++++++++++++ > 4 files changed, 339 insertions(+) > create mode 100644 drivers/iio/adc/max14001.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index dcea2c31f920..b527cf471d7a 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -12676,6 +12676,7 @@ L: linux-iio@xxxxxxxxxxxxxxx > S: Supported > W: https://ez.analog.com/linux-software-drivers > F: Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml > +F: drivers/iio/adc/max14001.c > > MAXBOTIX ULTRASONIC RANGER IIO DRIVER > M: Andreas Klinger <ak@xxxxxxxxxxxxx> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index eb2b09ef5d5b..e599d166e98d 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -706,6 +706,16 @@ config MAX11410 > To compile this driver as a module, choose M here: the module will be > called max11410. > > +config MAX14001 > + tristate "Analog Devices MAX14001 ADC driver" > + depends on SPI > + help > + Say yes here to build support for Analog Devices MAX14001 Configurable, > + Isolated 10-bit ADCs for Multi-Range Binary Inputs. > + > + To compile this driver as a module, choose M here: the module will be > + called max14001. > + > config MAX1241 > tristate "Maxim max1241 ADC driver" > depends on SPI_MASTER > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index e07e4a3e6237..9f8964258f03 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX11100) += max11100.o > obj-$(CONFIG_MAX1118) += max1118.o > obj-$(CONFIG_MAX11205) += max11205.o > obj-$(CONFIG_MAX11410) += max11410.o > +obj-$(CONFIG_MAX14001) += max14001.o > obj-$(CONFIG_MAX1241) += max1241.o > obj-$(CONFIG_MAX1363) += max1363.o > obj-$(CONFIG_MAX9611) += max9611.o > diff --git a/drivers/iio/adc/max14001.c b/drivers/iio/adc/max14001.c > new file mode 100644 > index 000000000000..b4d10539398b > --- /dev/null > +++ b/drivers/iio/adc/max14001.c > @@ -0,0 +1,327 @@ > +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) > +/* > + * Analog Devices MAX14001 ADC driver > + * > + * Copyright 2023 Analog Devices Inc. > + */ > + > +#include <linux/bitfield.h> > +#include <linux/bitrev.h> > +#include <linux/device.h> > +#include <linux/iio/iio.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/mod_devicetable.h> > +#include <linux/property.h> > +#include <linux/regulator/consumer.h> > +#include <linux/spi/spi.h> > +#include <linux/slab.h> > +#include <linux/types.h> > + > +#include <asm/unaligned.h> > + > +/* MAX14001 Registers Address */ > +#define MAX14001_ADC 0x00 > +#define MAX14001_FADC 0x01 > +#define MAX14001_FLAGS 0x02 > +#define MAX14001_FLTEN 0x03 > +#define MAX14001_THL 0x04 > +#define MAX14001_THU 0x05 > +#define MAX14001_INRR 0x06 > +#define MAX14001_INRT 0x07 > +#define MAX14001_INRP 0x08 > +#define MAX14001_CFG 0x09 > +#define MAX14001_ENBL 0x0A > +#define MAX14001_ACT 0x0B > +#define MAX14001_WEN 0x0C > + > +#define MAX14001_VERIFICATION_REG(x) ((x) + 0x10) > + > +#define MAX14001_CFG_EXRF BIT(5) > + > +#define MAX14001_ADDR_MASK GENMASK(15, 11) > +#define MAX14001_DATA_MASK GENMASK(9, 0) > +#define MAX14001_FILTER_MASK GENMASK(3, 2) > + > +#define MAX14001_SET_WRITE_BIT BIT(10) > +#define MAX14001_WRITE_WEN 0x294 > + > +struct max14001_state { > + struct spi_device *spi; > + /* > + * lock protect against multiple concurrent accesses, RMW sequence, and > + * SPI transfer > + */ > + struct mutex lock; > + int vref_mv; > + /* > + * DMA (thus cache coherency maintenance) requires the > + * transfer buffers to live in their own cache lines. > + */ > + __be16 spi_tx_buffer __aligned(IIO_DMA_MINALIGN); > + __be16 spi_rx_buffer; > +}; > + > +static int max14001_read(void *context, unsigned int reg_addr, unsigned int *data) > +{ > + struct max14001_state *st = context; > + int ret; > + > + struct spi_transfer xfers[] = { > + { > + .tx_buf = &st->spi_tx_buffer, > + .len = sizeof(st->spi_tx_buffer), > + .cs_change = 1, > + }, { > + .rx_buf = &st->spi_rx_buffer, > + .len = sizeof(st->spi_rx_buffer), > + }, > + }; > + > + st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK, > + reg_addr))); > + > + ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); > + if (ret) > + return ret; > + > + *data = bitrev16(be16_to_cpu(st->spi_rx_buffer)) & MAX14001_DATA_MASK; > + > + return 0; > +} > + > +static int max14001_write(void *context, unsigned int reg_addr, unsigned int data) > +{ > + struct max14001_state *st = context; > + > + st->spi_tx_buffer = bitrev16(cpu_to_be16( > + FIELD_PREP(MAX14001_ADDR_MASK, reg_addr) | > + FIELD_PREP(MAX14001_SET_WRITE_BIT, 1) | > + FIELD_PREP(MAX14001_DATA_MASK, data))); > + > + return spi_write(st->spi, &st->spi_tx_buffer, sizeof(st->spi_tx_buffer)); > +} > + > +static int max14001_write_verification_reg(struct max14001_state *st, > + unsigned int reg_addr) > +{ > + unsigned int reg_data; > + int ret; > + > + ret = max14001_read(st, reg_addr, ®_data); > + if (ret) > + return ret; > + > + return max14001_write(st, MAX14001_VERIFICATION_REG(reg_addr), reg_data); > +} > + > +static int max14001_reg_update(struct max14001_state *st, > + unsigned int reg_addr, > + unsigned int mask, > + unsigned int val) > +{ > + int ret; > + unsigned int reg_data; > + > + /* Enable SPI Registers Write */ > + ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN); > + if (ret) > + return ret; > + > + ret = max14001_read(st, reg_addr, ®_data); > + if (ret) > + return ret; > + > + reg_data = FIELD_PREP(mask, val); > + > + ret = max14001_write(st, reg_addr, reg_data); > + if (ret) > + return ret; > + > + /* Write Verification Register */ > + ret = max14001_write_verification_reg(st, reg_addr); > + if (ret) > + return ret; > + > + /* Disable SPI Registers Write */ > + return max14001_write(st, MAX14001_WEN, 0); > +} > + > +static int max14001_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct max14001_state *st = iio_priv(indio_dev); > + unsigned int data; > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + mutex_lock(&st->lock); > + ret = max14001_read(st, MAX14001_ADC, &data); > + mutex_unlock(&st->lock); > + if (ret < 0) > + return ret; > + > + *val = data; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + *val = st->vref_mv; > + *val2 = 10; > + > + return IIO_VAL_FRACTIONAL_LOG2; > + > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info max14001_info = { > + .read_raw = max14001_read_raw, > +}; > + > +static const struct iio_chan_spec max14001_channels[] = { > + { > + .type = IIO_VOLTAGE, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > + BIT(IIO_CHAN_INFO_SCALE), > + } > +}; > + > +static void max14001_regulator_disable(void *data) > +{ > + struct regulator *reg = data; > + > + regulator_disable(reg); > +} > + > +static int max14001_init(struct max14001_state *st) > +{ > + int ret; > + > + /* Enable SPI Registers Write */ > + ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN); > + if (ret) > + return ret; > + > + /* > + * Reads all registers and writes the values back to their appropriate > + * verification registers to clear the Memory Validation fault. > + */ > + ret = max14001_write_verification_reg(st, MAX14001_FLTEN); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_THL); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_THU); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_INRR); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_INRT); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_INRP); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_CFG); > + if (ret) > + return ret; > + > + ret = max14001_write_verification_reg(st, MAX14001_ENBL); > + if (ret) > + return ret; > + > + /* Disable SPI Registers Write */ > + return max14001_write(st, MAX14001_WEN, 0); > +} > + > +static int max14001_probe(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev; > + struct max14001_state *st; > + struct regulator *vref; > + struct device *dev = &spi->dev; > + int ret; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + st = iio_priv(indio_dev); > + st->spi = spi; > + > + indio_dev->name = "max14001"; > + indio_dev->info = &max14001_info; > + indio_dev->channels = max14001_channels; > + indio_dev->num_channels = ARRAY_SIZE(max14001_channels); > + indio_dev->modes = INDIO_DIRECT_MODE; > + > + ret = max14001_init(st); > + if (ret) > + return ret; > + > + vref = devm_regulator_get_optional(dev, "vref"); > + if (IS_ERR(vref)) { > + if (PTR_ERR(vref) != -ENODEV) > + return dev_err_probe(dev, PTR_ERR(vref), > + "Failed to get vref regulator"); > + > + /* internal reference */ > + st->vref_mv = 1250; > + } else { > + ret = regulator_enable(vref); > + if (ret) > + return dev_err_probe(dev, ret, > + "Failed to enable vref regulators\n"); > + > + ret = devm_add_action_or_reset(dev, max14001_regulator_disable, > + vref); > + if (ret) > + return ret; > + /* select external voltage reference source for the ADC */ > + ret = max14001_reg_update(st, MAX14001_CFG, > + MAX14001_CFG_EXRF, 1); > + > + ret = regulator_get_voltage(vref); > + if (ret < 0) > + return dev_err_probe(dev, ret, > + "Failed to get vref\n"); Is it important to choose the external reference source _before_ getting the voltage of the regulator? If not, I would swap these calls, otherwise the comment is needed to explain why the sequence is important in the way it's written. > + st->vref_mv = ret / 1000; > + } > + > + mutex_init(&st->lock); > + > + return devm_iio_device_register(dev, indio_dev); > +} > + > +static const struct of_device_id max14001_of_match[] = { > + { .compatible = "adi,max14001" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, max14001_of_match); > + > +static struct spi_driver max14001_driver = { > + .driver = { > + .name = "max14001", > + .of_match_table = max14001_of_match, > + }, > + .probe = max14001_probe, > +}; > +module_spi_driver(max14001_driver); > + > +MODULE_AUTHOR("Kim Seer Paller"); > +MODULE_DESCRIPTION("MAX14001 ADC driver"); > +MODULE_LICENSE("GPL"); > -- > 2.34.1 > -- With Best Regards, Andy Shevchenko
