1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Based on ltc2497.c which has
6*4882a593Smuzhiyun * Copyright (C) 2017 Analog Devices Inc.
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * Licensed under the GPL-2.
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #include <linux/spi/spi.h>
14*4882a593Smuzhiyun #include <linux/iio/iio.h>
15*4882a593Smuzhiyun #include <linux/iio/driver.h>
16*4882a593Smuzhiyun #include <linux/module.h>
17*4882a593Smuzhiyun #include <linux/mod_devicetable.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #include "ltc2497.h"
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun struct ltc2496_driverdata {
22*4882a593Smuzhiyun /* this must be the first member */
23*4882a593Smuzhiyun struct ltc2497core_driverdata common_ddata;
24*4882a593Smuzhiyun struct spi_device *spi;
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun /*
27*4882a593Smuzhiyun * DMA (thus cache coherency maintenance) requires the
28*4882a593Smuzhiyun * transfer buffers to live in their own cache lines.
29*4882a593Smuzhiyun */
30*4882a593Smuzhiyun unsigned char rxbuf[3] ____cacheline_aligned;
31*4882a593Smuzhiyun unsigned char txbuf[3];
32*4882a593Smuzhiyun };
33*4882a593Smuzhiyun
ltc2496_result_and_measure(struct ltc2497core_driverdata * ddata,u8 address,int * val)34*4882a593Smuzhiyun static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata,
35*4882a593Smuzhiyun u8 address, int *val)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun struct ltc2496_driverdata *st =
38*4882a593Smuzhiyun container_of(ddata, struct ltc2496_driverdata, common_ddata);
39*4882a593Smuzhiyun struct spi_transfer t = {
40*4882a593Smuzhiyun .tx_buf = st->txbuf,
41*4882a593Smuzhiyun .rx_buf = st->rxbuf,
42*4882a593Smuzhiyun .len = sizeof(st->txbuf),
43*4882a593Smuzhiyun };
44*4882a593Smuzhiyun int ret;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun st->txbuf[0] = LTC2497_ENABLE | address;
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun ret = spi_sync_transfer(st->spi, &t, 1);
49*4882a593Smuzhiyun if (ret < 0) {
50*4882a593Smuzhiyun dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n",
51*4882a593Smuzhiyun ERR_PTR(ret));
52*4882a593Smuzhiyun return ret;
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun if (val)
56*4882a593Smuzhiyun *val = ((st->rxbuf[0] & 0x3f) << 12 |
57*4882a593Smuzhiyun st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) -
58*4882a593Smuzhiyun (1 << 17);
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun return 0;
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun
ltc2496_probe(struct spi_device * spi)63*4882a593Smuzhiyun static int ltc2496_probe(struct spi_device *spi)
64*4882a593Smuzhiyun {
65*4882a593Smuzhiyun struct iio_dev *indio_dev;
66*4882a593Smuzhiyun struct ltc2496_driverdata *st;
67*4882a593Smuzhiyun struct device *dev = &spi->dev;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
70*4882a593Smuzhiyun if (!indio_dev)
71*4882a593Smuzhiyun return -ENOMEM;
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun st = iio_priv(indio_dev);
74*4882a593Smuzhiyun spi_set_drvdata(spi, indio_dev);
75*4882a593Smuzhiyun st->spi = spi;
76*4882a593Smuzhiyun st->common_ddata.result_and_measure = ltc2496_result_and_measure;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun return ltc2497core_probe(dev, indio_dev);
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
ltc2496_remove(struct spi_device * spi)81*4882a593Smuzhiyun static int ltc2496_remove(struct spi_device *spi)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun struct iio_dev *indio_dev = spi_get_drvdata(spi);
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun ltc2497core_remove(indio_dev);
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun return 0;
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun static const struct of_device_id ltc2496_of_match[] = {
91*4882a593Smuzhiyun { .compatible = "lltc,ltc2496", },
92*4882a593Smuzhiyun {},
93*4882a593Smuzhiyun };
94*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, ltc2496_of_match);
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun static struct spi_driver ltc2496_driver = {
97*4882a593Smuzhiyun .driver = {
98*4882a593Smuzhiyun .name = "ltc2496",
99*4882a593Smuzhiyun .of_match_table = ltc2496_of_match,
100*4882a593Smuzhiyun },
101*4882a593Smuzhiyun .probe = ltc2496_probe,
102*4882a593Smuzhiyun .remove = ltc2496_remove,
103*4882a593Smuzhiyun };
104*4882a593Smuzhiyun module_spi_driver(ltc2496_driver);
105*4882a593Smuzhiyun
106*4882a593Smuzhiyun MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>");
107*4882a593Smuzhiyun MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver");
108*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
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