On Mon, 2019-11-11 at 22:40 +0100, Uwe Kleine-König wrote: > This chip is similar to the LTC2497 ADC, it just uses SPI instead of I2C > and so has a slightly different protocol. The channel definitions are > shared between the two drivers. Much of this code is duplicated from the i2c/base ltc2497.o driver. I would leave most of this code in the base/common driver and export the i2c/spi read hooks. You can check [as an example] the ad7606 driver. That one passes some bus_ops struct from the SPI & Parallel drivers to the common probe. I agree that regmap isn't usable here, but a bus_ops struct [that is defined in ltc2497.h] should be doable. Thanks Alex > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > --- > drivers/iio/adc/Kconfig | 10 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/ltc2496.c | 208 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 219 insertions(+) > create mode 100644 drivers/iio/adc/ltc2496.c > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index f0af3a42f53c..deb86f6039b3 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -492,6 +492,16 @@ config LTC2485 > To compile this driver as a module, choose M here: the module > will be > called ltc2485. > > +config LTC2496 > + tristate "Linear Technology LTC2496 ADC driver" > + depends on SPI Regarding [patch2-note1], this Kconfig symbols would be LTC2497_SPI > + help > + Say yes here to build support for Linear Technology LTC2496 > + 16-Bit 8-/16-Channel Delta Sigma ADC. > + > + To compile this driver as a module, choose M here: the module > will be > + called ltc2496. > + > config LTC2497 Regarding [patch2-note1], this Kconfig symbols would become LTC2497_I2C. And a new config LTC2497 could be added, but without any title, so that it cannot be selected in menuconfig. > tristate "Linear Technology LTC2497 ADC driver" > depends on I2C > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index 660242c2cca7..afe2b6db4a5e 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -47,6 +47,7 @@ obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o > obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o > obj-$(CONFIG_LTC2471) += ltc2471.o > obj-$(CONFIG_LTC2485) += ltc2485.o > +obj-$(CONFIG_LTC2496) += ltc2496.o ltc249x.o > obj-$(CONFIG_LTC2497) += ltc2497.o ltc249x.o > obj-$(CONFIG_MAX1027) += max1027.o > obj-$(CONFIG_MAX11100) += max11100.o > diff --git a/drivers/iio/adc/ltc2496.c b/drivers/iio/adc/ltc2496.c > new file mode 100644 > index 000000000000..0b0a7aa8987f > --- /dev/null > +++ b/drivers/iio/adc/ltc2496.c > @@ -0,0 +1,208 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC > + * > + * Based on ltc2497.c which has > + * Copyright (C) 2017 Analog Devices Inc. > + * > + * Licensed under the GPL-2. > + * > + * Datasheet: > https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf > + */ > + > +#include <linux/delay.h> > +#include <linux/spi/spi.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/driver.h> > +#include <linux/iio/sysfs.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/regulator/consumer.h> > + > +#include "ltc249x.h" > + > +struct ltc2496_st { > + struct spi_device *spi; > + struct regulator *ref; > + ktime_t time_prev; > + u8 addr_prev; > +}; > + > +static int ltc2496_wait_conv(struct ltc2496_st *st) > +{ > + s64 time_elapsed; > + > + time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev); > + > + if (time_elapsed < LTC249X_CONVERSION_TIME_MS) { > + /* delay if conversion time not passed > + * since last read or write > + */ > + if (msleep_interruptible( > + LTC249X_CONVERSION_TIME_MS - time_elapsed)) > + return -ERESTARTSYS; > + > + return 0; > + } > + > + if (time_elapsed - LTC249X_CONVERSION_TIME_MS <= 0) { > + /* We're in automatic mode - > + * so the last reading is still not outdated > + */ > + return 0; > + } > + > + return 1; > +} > + > +static int ltc2496_read(struct ltc2496_st *st, u8 address, int *val) > +{ > + struct spi_device *spi = st->spi; > + int ret; > + unsigned char txbuf[3] = { LTC249X_ENABLE | address, }; > + unsigned char rxbuf[3]; > + struct spi_transfer t = { > + .tx_buf = txbuf, > + .rx_buf = rxbuf, > + .len = sizeof(txbuf), > + }; > + > + ret = ltc2496_wait_conv(st); > + if (ret < 0) > + return ret; > + > + if (ret || st->addr_prev != address) { > + ret = spi_sync_transfer(spi, &t, 1); > + if (ret < 0) > + return ret; > + st->addr_prev = address; > + if (msleep_interruptible(LTC249X_CONVERSION_TIME_MS)) > + return -ERESTARTSYS; > + } > + > + ret = spi_sync_transfer(spi, &t, 1); > + if (ret < 0) { > + dev_err(&spi->dev, "spi_sync_transfer failed\n"); > + return ret; > + } > + st->time_prev = ktime_get(); > + > + /* convert and shift the result, > + * and finally convert from offset binary to signed integer > + */ > + *val = ((rxbuf[0] & 0x3f) << 12 | rxbuf[1] << 4 | rxbuf[2] >> 4) > + - (1 << 17); > + > + return ret; > +} > + int *val, int *val2, long mask) > +{ > + struct ltc2496_st *st = iio_priv(indio_dev); > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + mutex_lock(&indio_dev->mlock); > + ret = ltc2496_read(st, chan->address, val); > + mutex_unlock(&indio_dev->mlock); > + if (ret < 0) > + return ret; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + ret = regulator_get_voltage(st->ref); > + if (ret < 0) > + return ret; > + > + *val = ret / 1000; > + *val2 = 17; > + > + return IIO_VAL_FRACTIONAL_LOG2; > + > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info ltc2496_info = { > + .read_raw = ltc2496_read_raw, > +}; > + > +static int ltc2496_probe(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev; > + struct ltc2496_st *st; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + st = iio_priv(indio_dev); > + spi_set_drvdata(spi, indio_dev); > + st->spi = spi; > + > + indio_dev->dev.parent = &spi->dev; > + indio_dev->name = "ltc2496"; > + indio_dev->info = <c2496_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = ltc249x_channel; > + indio_dev->num_channels = ltc249x_num_channels; > + > + st->ref = devm_regulator_get(&spi->dev, "vref"); > + if (IS_ERR(st->ref)) > + return PTR_ERR(st->ref); > + > + ret = regulator_enable(st->ref); > + if (ret < 0) > + return ret; > + > + st->addr_prev = 0; > + st->time_prev = ktime_get(); > + > + ret = iio_device_register(indio_dev); > + if (ret < 0) > + goto err_regulator_disable; > + > + return 0; > + > +err_regulator_disable: > + regulator_disable(st->ref); > + > + return ret; > +} > + > +static int ltc2496_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + struct ltc2496_st *st = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + regulator_disable(st->ref); > + > + return 0; > +} > + > +static const struct of_device_id ltc2496_of_match[] = { > + { .compatible = "lltc,ltc2496", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, ltc2496_of_match); > + > +static struct spi_driver ltc2496_driver = { > + .driver = { > + .name = "ltc2496", > + .of_match_table = of_match_ptr(ltc2496_of_match), > + }, > + .probe = ltc2496_probe, > + .remove = ltc2496_remove, > +}; > +module_spi_driver(ltc2496_driver); > + > +MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@xxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver"); > +MODULE_LICENSE("GPL v2");
