1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC |
4 | * |
5 | * Based on ltc2497.c which has |
6 | * 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.pdf |
11 | */ |
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 | |
22 | struct 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 the |
29 | * 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 | |
35 | static 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(spi: st->spi, xfers: &t, num_xfers: 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 | |
64 | static 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(parent: dev, sizeof_priv: sizeof(*st)); |
71 | if (!indio_dev) |
72 | return -ENOMEM; |
73 | |
74 | st = iio_priv(indio_dev); |
75 | spi_set_drvdata(spi, data: 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 | |
83 | static 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 | |
90 | static const struct ltc2497_chip_info ltc2496_info = { |
91 | .resolution = 16, |
92 | .name = NULL, |
93 | }; |
94 | |
95 | static const struct of_device_id ltc2496_of_match[] = { |
96 | { .compatible = "lltc,ltc2496" , .data = <c2496_info, }, |
97 | {}, |
98 | }; |
99 | MODULE_DEVICE_TABLE(of, ltc2496_of_match); |
100 | |
101 | static 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 | }; |
109 | module_spi_driver(ltc2496_driver); |
110 | |
111 | MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>" ); |
112 | MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver" ); |
113 | MODULE_LICENSE("GPL v2" ); |
114 | |