On Fri, 2020-03-20 at 07:06 +0000, Ardelean, Alexandru wrote: > [External] > > On Thu, 2020-03-19 at 18:29 +0200, Alexandru Lazar wrote: > > Add driver for the Maxim MAX1241 12-bit, single-channel ADC. The driver > > includes support for this device's low-power operation mode. > > > > Reviewed-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> before I forget; if you do a V4 [or above] you can add my Reviewed-by tag to this patch > > > Signed-off-by: Alexandru Lazar <alazar@xxxxxxxxxxxxx> > > --- > > drivers/iio/adc/Kconfig | 10 ++ > > drivers/iio/adc/Makefile | 1 + > > drivers/iio/adc/max1241.c | 206 ++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 217 insertions(+) > > create mode 100644 drivers/iio/adc/max1241.c > > > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > > index 5d8540b7b427..55f6462cd93f 100644 > > --- a/drivers/iio/adc/Kconfig > > +++ b/drivers/iio/adc/Kconfig > > @@ -566,6 +566,16 @@ config MAX1118 > > To compile this driver as a module, choose M here: the module will be > > called max1118. > > > > +config MAX1241 > > + tristate "Maxim max1241 ADC driver" > > + depends on SPI_MASTER > > + help > > + Say yes here to build support for Maxim max1241 12-bit, single-channel > > + ADC. > > + > > + To compile this driver as a module, choose M here: the module will be > > + called max1241. > > + > > config MAX1363 > > tristate "Maxim max1363 ADC driver" > > depends on I2C > > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > > index a1f1fbec0f87..37d6f17559dc 100644 > > --- a/drivers/iio/adc/Makefile > > +++ b/drivers/iio/adc/Makefile > > @@ -54,6 +54,7 @@ obj-$(CONFIG_LTC2497) += ltc2497.o > > obj-$(CONFIG_MAX1027) += max1027.o > > obj-$(CONFIG_MAX11100) += max11100.o > > obj-$(CONFIG_MAX1118) += max1118.o > > +obj-$(CONFIG_MAX1241) += max1241.o > > obj-$(CONFIG_MAX1363) += max1363.o > > obj-$(CONFIG_MAX9611) += max9611.o > > obj-$(CONFIG_MCP320X) += mcp320x.o > > diff --git a/drivers/iio/adc/max1241.c b/drivers/iio/adc/max1241.c > > new file mode 100644 > > index 000000000000..0278510ec346 > > --- /dev/null > > +++ b/drivers/iio/adc/max1241.c > > @@ -0,0 +1,206 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * MAX1241 low-power, 12-bit serial ADC > > + * > > + * Datasheet: > > https://datasheets.maximintegrated.com/en/ds/MAX1240-MAX1241.pdf > > + */ > > + > > +#include <linux/regulator/consumer.h> > > +#include <linux/delay.h> > > +#include <linux/gpio/consumer.h> > > +#include <linux/iio/iio.h> > > +#include <linux/module.h> > > +#include <linux/spi/spi.h> > > + > > +#define MAX1241_VAL_MASK 0xFFF > > +#define MAX1241_SHDN_DELAY_USEC 4 > > + > > +enum max1241_id { > > + max1241, > > +}; > > + > > +struct max1241 { > > + struct spi_device *spi; > > + struct mutex lock; > > + struct regulator *reg; > > + struct gpio_desc *shdn; > > + > > + __be16 data ____cacheline_aligned; > > +}; > > + > > +static const struct iio_chan_spec max1241_channels[] = { > > + { > > + .type = IIO_VOLTAGE, > > + .indexed = 1, > > + .channel = 0, > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > > + BIT(IIO_CHAN_INFO_SCALE), > > + .scan_index = 0, > > + .scan_type = { > > + .sign = 'u', > > + .realbits = 12, > > + .storagebits = 16, > > + }, > > + }, > > +}; > > + > > +static int max1241_read(struct max1241 *adc) > > +{ > > + struct spi_transfer xfers[] = { > > + /* > > + * Begin conversion by bringing /CS low for at least > > + * tconv us. > > + */ > > + { > > + .len = 0, > > + .delay.value = 8, > > + .delay.unit = SPI_DELAY_UNIT_USECS, > > + }, > > + /* > > + * Then read two bytes of data in our RX buffer. > > + */ > > + { > > + .rx_buf = &adc->data, > > + .len = 2, > > + }, > > + }; > > + > > + return spi_sync_transfer(adc->spi, xfers, ARRAY_SIZE(xfers)); > > +} > > + > > +static int max1241_read_raw(struct iio_dev *indio_dev, > > + struct iio_chan_spec const *chan, > > + int *val, int *val2, long mask) > > +{ > > + int ret, vref_uV; > > + struct max1241 *adc = iio_priv(indio_dev); > > + > > + switch (mask) { > > + case IIO_CHAN_INFO_RAW: > > + mutex_lock(&adc->lock); > > + > > + if (adc->shdn) { > > + gpiod_set_value(adc->shdn, 0); > > + udelay(MAX1241_SHDN_DELAY_USEC); > > + } > > + > > + ret = max1241_read(adc); > > + > > + if (adc->shdn) > > + gpiod_set_value(adc->shdn, 1); > > + > > + if (ret) { > > + mutex_unlock(&adc->lock); > > + return ret; > > + } > > + > > + *val = (be16_to_cpu(adc->data) >> 3) & MAX1241_VAL_MASK; > > + > > + mutex_unlock(&adc->lock); > > + return IIO_VAL_INT; > > + case IIO_CHAN_INFO_SCALE: > > + vref_uV = regulator_get_voltage(adc->reg); > > + > > + if (vref_uV < 0) > > + return vref_uV; > > + > > + *val = vref_uV / 1000; > > + *val2 = 12; > > + > > + return IIO_VAL_FRACTIONAL_LOG2; > > + default: > > + return -EINVAL; > > + } > > +} > > + > > +static const struct iio_info max1241_info = { > > + .read_raw = max1241_read_raw, > > +}; > > + > > +static void max1241_disable_reg_action(void *data) > > +{ > > + struct max1241 *adc = data; > > + int err; > > + > > + err = regulator_disable(adc->reg); > > + if (err) > > + dev_err(&adc->spi->dev, "could not disable reference > > regulator.\n"); > > +} > > + > > +static int max1241_probe(struct spi_device *spi) > > +{ > > + struct iio_dev *indio_dev; > > + struct max1241 *adc; > > + int ret = 0; > > + > > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); > > + if (!indio_dev) > > + return -ENOMEM; > > + > > + adc = iio_priv(indio_dev); > > + adc->spi = spi; > > + mutex_init(&adc->lock); > > + > > + spi_set_drvdata(spi, indio_dev); > > + > > + adc->reg = devm_regulator_get(&spi->dev, "vref"); > > + if (IS_ERR(adc->reg)) { > > + dev_err(&spi->dev, "failed to get vref regulator\n"); > > + return PTR_ERR(adc->reg); > > + } > > + > > + ret = regulator_enable(adc->reg); > > + if (ret) > > + return ret; > > + > > + ret = devm_add_action_or_reset(&spi->dev, max1241_disable_reg_action, > > + adc); > > + if (ret) { > > + dev_err(&spi->dev, "could not set up regulator cleanup > > action!\n"); > > + return ret; > > + } > > + > > + adc->shdn = devm_gpiod_get_optional(&spi->dev, "shdn", GPIOD_OUT_HIGH); > > + > > + if (IS_ERR(adc->shdn)) > > + return PTR_ERR(adc->shdn); > > + > > + if (!adc->shdn) > > + dev_dbg(&spi->dev, "no shdn pin passed, low-power mode > > disabled"); > > + else > > + dev_dbg(&spi->dev, "shdn pin passed, low-power mode enabled"); > > + > > + indio_dev->name = spi_get_device_id(spi)->name; > > + indio_dev->dev.parent = &spi->dev; > > + indio_dev->info = &max1241_info; > > + indio_dev->modes = INDIO_DIRECT_MODE; > > + indio_dev->channels = max1241_channels; > > + indio_dev->num_channels = ARRAY_SIZE(max1241_channels); > > + > > + return devm_iio_device_register(&spi->dev, indio_dev); > > +} > > + > > +static const struct spi_device_id max1241_id[] = { > > + { "max1241", max1241 }, > > + {}, > > +}; > > + > > +static const struct of_device_id max1241_dt_ids[] = { > > + { .compatible = "maxim,max1241" }, > > + {}, > > +}; > > +MODULE_DEVICE_TABLE(of, max1241_dt_ids); > > + > > +static struct spi_driver max1241_spi_driver = { > > + .driver = { > > + .name = "max1241", > > + .of_match_table = max1241_dt_ids, > > + }, > > + .probe = max1241_probe, > > + .id_table = max1241_id, > > +}; > > +module_spi_driver(max1241_spi_driver); > > + > > +MODULE_AUTHOR("Alexandru Lazar <alazar@xxxxxxxxxxxxx>"); > > +MODULE_DESCRIPTION("MAX1241 ADC driver"); > > +MODULE_LICENSE("GPL v2");
