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 __maybe_unused ad714x_spi_suspend(struct device *dev)
19{
20	return ad714x_disable(spi_get_drvdata(to_spi_device(dev)));
21}
22
23static int __maybe_unused ad714x_spi_resume(struct device *dev)
24{
25	return ad714x_enable(spi_get_drvdata(to_spi_device(dev)));
26}
27
28static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
29
30static int ad714x_spi_read(struct ad714x_chip *chip,
31			   unsigned short reg, unsigned short *data, size_t len)
32{
33	struct spi_device *spi = to_spi_device(chip->dev);
34	struct spi_message message;
35	struct spi_transfer xfer[2];
36	int i;
37	int error;
38
39	spi_message_init(&message);
40	memset(xfer, 0, sizeof(xfer));
41
42	chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
43					AD714x_SPI_READ | reg);
44	xfer[0].tx_buf = &chip->xfer_buf[0];
45	xfer[0].len = sizeof(chip->xfer_buf[0]);
46	spi_message_add_tail(&xfer[0], &message);
47
48	xfer[1].rx_buf = &chip->xfer_buf[1];
49	xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
50	spi_message_add_tail(&xfer[1], &message);
51
52	error = spi_sync(spi, &message);
53	if (unlikely(error)) {
54		dev_err(chip->dev, "SPI read error: %d\n", error);
55		return error;
56	}
57
58	for (i = 0; i < len; i++)
59		data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
60
61	return 0;
62}
63
64static int ad714x_spi_write(struct ad714x_chip *chip,
65			    unsigned short reg, unsigned short data)
66{
67	struct spi_device *spi = to_spi_device(chip->dev);
68	int error;
69
70	chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
71	chip->xfer_buf[1] = cpu_to_be16(data);
72
73	error = spi_write(spi, (u8 *)chip->xfer_buf,
74			  2 * sizeof(*chip->xfer_buf));
75	if (unlikely(error)) {
76		dev_err(chip->dev, "SPI write error: %d\n", error);
77		return error;
78	}
79
80	return 0;
81}
82
83static int ad714x_spi_probe(struct spi_device *spi)
84{
85	struct ad714x_chip *chip;
86	int err;
87
88	spi->bits_per_word = 8;
89	err = spi_setup(spi);
90	if (err < 0)
91		return err;
92
93	chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
94			    ad714x_spi_read, ad714x_spi_write);
95	if (IS_ERR(chip))
96		return PTR_ERR(chip);
97
98	spi_set_drvdata(spi, chip);
99
100	return 0;
101}
102
103static struct spi_driver ad714x_spi_driver = {
104	.driver = {
105		.name	= "ad714x_captouch",
106		.pm	= &ad714x_spi_pm,
107	},
108	.probe		= ad714x_spi_probe,
109};
110
111module_spi_driver(ad714x_spi_driver);
112
113MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
114MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
115MODULE_LICENSE("GPL");
116