This chip is similar to the LTC2497 ADC, it just uses SPI instead of I2C and so has a slightly different protocol. Only the actual hardware access is different. The spi protocol is different enough to not be able to map the differences via a regmap. Also generalize the entry in MAINTAINER to cover the newly introduced file. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> --- MAINTAINERS | 2 +- drivers/iio/adc/Kconfig | 10 ++++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ltc2496.c | 108 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 120 insertions(+), 1 deletion(-) create mode 100644 drivers/iio/adc/ltc2496.c diff --git a/MAINTAINERS b/MAINTAINERS index eb19fad370d7..8b1211038617 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1029,7 +1029,7 @@ S: Supported F: Documentation/ABI/testing/sysfs-bus-iio-frequency-ad9523 F: Documentation/ABI/testing/sysfs-bus-iio-frequency-adf4350 F: drivers/iio/*/ad* -F: drivers/iio/adc/ltc2497* +F: drivers/iio/adc/ltc249* X: drivers/iio/*/adjd* F: drivers/staging/iio/*/ad* 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 + 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 tristate "Linear Technology LTC2497 ADC driver" depends on I2C diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index ee0c8dcfb501..c3dc2a12766a 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-$(CONFIG_LTC2496) += ltc2496.o ltc2497-core.o obj-$(CONFIG_LTC2497) += ltc2497.o ltc2497-core.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..a7659c8f9cc9 --- /dev/null +++ b/drivers/iio/adc/ltc2496.c @@ -0,0 +1,108 @@ +// 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/spi/spi.h> +#include <linux/iio/iio.h> +#include <linux/iio/driver.h> +#include <linux/module.h> +#include <linux/of.h> + +#include "ltc2497.h" + +struct ltc2496_driverdata { + /* this must be the first member */ + struct ltc2497core_driverdata common_ddata; + struct spi_device *spi; + + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + unsigned char rxbuf[3] ____cacheline_aligned; + unsigned char txbuf[3] ____cacheline_aligned; +}; + +static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata, + u8 address, int *val) +{ + struct ltc2496_driverdata *st = + container_of(ddata, struct ltc2496_driverdata, common_ddata); + struct spi_transfer t = { + .tx_buf = st->txbuf, + .rx_buf = st->rxbuf, + .len = sizeof(st->txbuf), + }; + int ret; + + st->txbuf[0] = LTC2497_ENABLE | address; + + ret = spi_sync_transfer(st->spi, &t, 1); + if (ret < 0) { + dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n", + ERR_PTR(ret)); + return ret; + } + + if (val) + *val = ((st->rxbuf[0] & 0x3f) << 12 | + st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) - + (1 << 17); + + return 0; +} + +static int ltc2496_probe(struct spi_device *spi) +{ + struct iio_dev *indio_dev; + struct ltc2496_driverdata *st; + struct device *dev = &spi->dev; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + spi_set_drvdata(spi, indio_dev); + st->spi = spi; + st->common_ddata.result_and_measure = ltc2496_result_and_measure; + + return ltc2497core_probe(dev, indio_dev); +} + +static int ltc2496_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + + ltc2497core_remove(indio_dev); + + 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"); -- 2.24.0
