diff options
Diffstat (limited to 'drivers/iio/adc/ltc2496.c')
| -rw-r--r-- | drivers/iio/adc/ltc2496.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/drivers/iio/adc/ltc2496.c b/drivers/iio/adc/ltc2496.c new file mode 100644 index 000000000..2593fa432 --- /dev/null +++ b/drivers/iio/adc/ltc2496.c @@ -0,0 +1,113 @@ +// 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/mod_devicetable.h> +#include <linux/property.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) may require the + * transfer buffers to live in their own cache lines. + */ + unsigned char rxbuf[3] __aligned(IIO_DMA_MINALIGN); + unsigned char txbuf[3]; +}; + +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; + st->common_ddata.chip_info = device_get_match_data(dev); + + return ltc2497core_probe(dev, indio_dev); +} + +static void ltc2496_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + + ltc2497core_remove(indio_dev); +} + +static const struct ltc2497_chip_info ltc2496_info = { + .resolution = 16, + .name = NULL, +}; + +static const struct of_device_id ltc2496_of_match[] = { + { .compatible = "lltc,ltc2496", .data = <c2496_info, }, + {}, +}; +MODULE_DEVICE_TABLE(of, ltc2496_of_match); + +static struct spi_driver ltc2496_driver = { + .driver = { + .name = "ltc2496", + .of_match_table = ltc2496_of_match, + }, + .probe = ltc2496_probe, + .remove = ltc2496_remove, +}; +module_spi_driver(ltc2496_driver); + +MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>"); +MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver"); +MODULE_LICENSE("GPL v2"); |