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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC4 *5 * Based on ltc2497.c which has6 * Copyright (C) 2017 Analog Devices Inc.7 *8 * Licensed under the GPL-2.9 *10 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf11 */12 13#include <linux/spi/spi.h>14#include <linux/iio/iio.h>15#include <linux/iio/driver.h>16#include <linux/module.h>17#include <linux/mod_devicetable.h>18#include <linux/property.h>19 20#include "ltc2497.h"21 22struct ltc2496_driverdata {23 /* this must be the first member */24 struct ltc2497core_driverdata common_ddata;25 struct spi_device *spi;26 27 /*28 * DMA (thus cache coherency maintenance) may require the29 * transfer buffers to live in their own cache lines.30 */31 unsigned char rxbuf[3] __aligned(IIO_DMA_MINALIGN);32 unsigned char txbuf[3];33};34 35static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata,36 u8 address, int *val)37{38 struct ltc2496_driverdata *st =39 container_of(ddata, struct ltc2496_driverdata, common_ddata);40 struct spi_transfer t = {41 .tx_buf = st->txbuf,42 .rx_buf = st->rxbuf,43 .len = sizeof(st->txbuf),44 };45 int ret;46 47 st->txbuf[0] = LTC2497_ENABLE | address;48 49 ret = spi_sync_transfer(st->spi, &t, 1);50 if (ret < 0) {51 dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n",52 ERR_PTR(ret));53 return ret;54 }55 56 if (val)57 *val = ((st->rxbuf[0] & 0x3f) << 12 |58 st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) -59 (1 << 17);60 61 return 0;62}63 64static int ltc2496_probe(struct spi_device *spi)65{66 struct iio_dev *indio_dev;67 struct ltc2496_driverdata *st;68 struct device *dev = &spi->dev;69 70 indio_dev = devm_iio_device_alloc(dev, sizeof(*st));71 if (!indio_dev)72 return -ENOMEM;73 74 st = iio_priv(indio_dev);75 spi_set_drvdata(spi, indio_dev);76 st->spi = spi;77 st->common_ddata.result_and_measure = ltc2496_result_and_measure;78 st->common_ddata.chip_info = device_get_match_data(dev);79 80 return ltc2497core_probe(dev, indio_dev);81}82 83static void ltc2496_remove(struct spi_device *spi)84{85 struct iio_dev *indio_dev = spi_get_drvdata(spi);86 87 ltc2497core_remove(indio_dev);88}89 90static const struct ltc2497_chip_info ltc2496_info = {91 .resolution = 16,92 .name = NULL,93};94 95static const struct of_device_id ltc2496_of_match[] = {96 { .compatible = "lltc,ltc2496", .data = <c2496_info, },97 { }98};99MODULE_DEVICE_TABLE(of, ltc2496_of_match);100 101static struct spi_driver ltc2496_driver = {102 .driver = {103 .name = "ltc2496",104 .of_match_table = ltc2496_of_match,105 },106 .probe = ltc2496_probe,107 .remove = ltc2496_remove,108};109module_spi_driver(ltc2496_driver);110 111MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>");112MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver");113MODULE_LICENSE("GPL v2");114