1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * AD714X CapTouch Programmable Controller driver (SPI bus)
4 *
5 * Copyright 2009-2011 Analog Devices Inc.
6 */
7
8#include <linux/input.h> /* BUS_SPI */
9#include <linux/module.h>
10#include <linux/spi/spi.h>
11#include <linux/pm.h>
12#include <linux/types.h>
13#include "ad714x.h"
14
15#define AD714x_SPI_CMD_PREFIX 0xE000 /* bits 15:11 */
16#define AD714x_SPI_READ BIT(10)
17
18static int ad714x_spi_read(struct ad714x_chip *chip,
19 unsigned short reg, unsigned short *data, size_t len)
20{
21 struct spi_device *spi = to_spi_device(chip->dev);
22 struct spi_message message;
23 struct spi_transfer xfer[2];
24 int i;
25 int error;
26
27 spi_message_init(m: &message);
28 memset(xfer, 0, sizeof(xfer));
29
30 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
31 AD714x_SPI_READ | reg);
32 xfer[0].tx_buf = &chip->xfer_buf[0];
33 xfer[0].len = sizeof(chip->xfer_buf[0]);
34 spi_message_add_tail(t: &xfer[0], m: &message);
35
36 xfer[1].rx_buf = &chip->xfer_buf[1];
37 xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
38 spi_message_add_tail(t: &xfer[1], m: &message);
39
40 error = spi_sync(spi, message: &message);
41 if (unlikely(error)) {
42 dev_err(chip->dev, "SPI read error: %d\n", error);
43 return error;
44 }
45
46 for (i = 0; i < len; i++)
47 data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
48
49 return 0;
50}
51
52static int ad714x_spi_write(struct ad714x_chip *chip,
53 unsigned short reg, unsigned short data)
54{
55 struct spi_device *spi = to_spi_device(chip->dev);
56 int error;
57
58 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
59 chip->xfer_buf[1] = cpu_to_be16(data);
60
61 error = spi_write(spi, buf: (u8 *)chip->xfer_buf,
62 len: 2 * sizeof(*chip->xfer_buf));
63 if (unlikely(error)) {
64 dev_err(chip->dev, "SPI write error: %d\n", error);
65 return error;
66 }
67
68 return 0;
69}
70
71static int ad714x_spi_probe(struct spi_device *spi)
72{
73 struct ad714x_chip *chip;
74 int err;
75
76 spi->bits_per_word = 8;
77 err = spi_setup(spi);
78 if (err < 0)
79 return err;
80
81 chip = ad714x_probe(dev: &spi->dev, BUS_SPI, irq: spi->irq,
82 read: ad714x_spi_read, write: ad714x_spi_write);
83 if (IS_ERR(ptr: chip))
84 return PTR_ERR(ptr: chip);
85
86 spi_set_drvdata(spi, data: chip);
87
88 return 0;
89}
90
91static struct spi_driver ad714x_spi_driver = {
92 .driver = {
93 .name = "ad714x_captouch",
94 .pm = pm_sleep_ptr(&ad714x_pm),
95 },
96 .probe = ad714x_spi_probe,
97};
98
99module_spi_driver(ad714x_spi_driver);
100
101MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
102MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
103MODULE_LICENSE("GPL");
104

source code of linux/drivers/input/misc/ad714x-spi.c