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(&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(&xfer[0], &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(&xfer[1], &message);
39
40	error = spi_sync(spi, &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, (u8 *)chip->xfer_buf,
62			  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(&spi->dev, BUS_SPI, spi->irq,
82			    ad714x_spi_read, ad714x_spi_write);
83	if (IS_ERR(chip))
84		return PTR_ERR(chip);
85
86	spi_set_drvdata(spi, 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